text stringlengths 454 608k | url stringlengths 17 896 | dump stringclasses 91 values | source stringclasses 1 value | word_count int64 101 114k | flesch_reading_ease float64 50 104 |
|---|---|---|---|---|---|
One.
While++; }
switch statements are useful when you want to have your program do many different things according to the value of a particular test variable.
An example usage of
switch statement is like this:
int a = 1; switch (a) { case 1: puts("a is 1"); break; case 2: puts("a is 2"); break; default: puts("a is neither 1 nor 2"); break; }
This example is equivalent to
int a = 1; if (a == 1) { puts("a is 1"); } else if (a == 2) { puts("a is 2"); } else { puts("a is neither 1 nor 2"); }
If the value of
a is 1 when the
switch statement is used,
a is 1 will be printed. If the value of
a is 2 then,
a is 2 will be printed. Otherwise,
a is neither 1 nor 2 will be printed.
case n: is used to describe where the execution flow will jump in when the value passed to
switch statement is n. n must be compile-time constant and the same n can exist at most once in one
switch statement.
default: is used to describe that when the value didn't match any of the choices for
case n:. It is a good practice to include a
default case in every switch statement to catch unexpected behavior.
A
break; statement is required to jump out of the
switch block.
Note: If you accidentally forget to add a
break after the end of a
case, the compiler will assume that you intend to "fall through" and all the subsequent case statements, if any, will be executed (unless a break statement is found in any of the subsequent cases), regardless of whether the subsequent case statement(s) match or not. This particular property is used to implement Duff's Device. This behavior is often considered a flaw in the C language specification.
Below is an example that shows effects of the absence of
break;:
int a = 1; switch (a) { case 1: case 2: puts("a is 1 or 2"); case 3: puts("a is 1, 2 or 3"); break; default: puts("a is neither 1, 2 nor 3"); break; }
When the value of
a is 1 or 2,
a is 1 or 2 and
a is 1, 2 or 3 will both be printed.
When
a is 3, only
a is 1, 2 or 3 will be printed. Otherwise,
a is neither 1, 2 nor 3 will be printed.
Note that the
default case is not necessary, especially when the set of values you get in the
switch is finished and known at compile time.
The best example is using a
switch on an
enum.
enum msg_type { ACK, PING, ERROR }; void f(enum msg_type t) { switch (t) { case ACK: // do nothing break; case PING: // do something break; case ERROR: // do something else break; } }
There are multiple advantages of doing this:
defaultcase were present)
enum, you will be notified of all the places where you forgot to handle the new value (with a
defaultcase, you would need to manually explore your code searching for such cases)
default:", whether there other
enumvalues or whether it is a protection for "just in case". And if there are other
enumvalues, did the coder intentionally use the
defaultcase for them or is there a bug that was introduced when he added the value?
enumvalue makes the code self explanatory as you can't hide behind a wild card, you must explicitly handle each of them.
Nevertheless, you can't prevent someone to write evil code like:
enum msg_type t = (enum msg_type)666; // I'm evil
Thus you may add an extra check before your switch to detect it, if you really need it.
void f(enum msg_type t) { if (!is_msg_type_valid(t)) { // Handle this unlikely error } switch(t) { // Same code than before } }
While the
if ()... else statement allows to define only one (default) behaviour which occurs when the condition within the
if () is not met, chaining two or more
if () ... else statements allow to define a couple more behaviours before going to the last
else branch acting as a "default", if any.
Example:
int a = ... /* initialise to some value. */ if (a >= 1) { printf("a is greater than or equals 1.\n"); } else if (a == 0) //we already know that a is smaller than 1 { printf("a equals 0.\n"); } else /* a is smaller than 1 and not equals 0, hence: */ { printf("a is negative.\n"); }
Nested
if()...else statements take more execution time (they are slower) in comparison to an
if()...else ladder because the nested
if()...else statements check all the inner conditional statements once the outer conditional
if() statement is satisfied, whereas the
if()..else ladder will stop condition testing once any of the
if() or the
else if() conditional statements are true.
An
if()...else ladder:
#include <stdio.h> int main(int argc, char *argv[]) { int a, b, c; printf("\nEnter Three numbers = "); scanf("%d%d%d", &a, &b, &c); if ((a < b) && (a < c)) { printf("\na = %d is the smallest.", a); } else if ((b < a) && (b < c)) { printf("\nb = %d is the smallest.", b); } else if ((c < a) && (c < b)) { printf("\nc = %d is the smallest.", c); } else { printf("\nImprove your coding logic"); } return 0; }
Is, in the general case, considered to be better than the equivalent nested
if()...else:
#include <stdio.h> int main(int argc, char *argv[]) { int a, b, c; printf("\nEnter Three numbers = "); scanf("%d%d%d", &a, &b, &c); if (a < b) { if (a < c) { printf("\na = %d is the smallest.", a); } else { printf("\nc = %d is the smallest.", c); } } else { if(b < c) { printf("\nb = %d is the smallest.", b); } else { printf("\nc = %d is the smallest.", c); } } return 0; } | https://sodocumentation.net/c/topic/3073/selection-statements | CC-MAIN-2021-21 | refinedweb | 950 | 68.6 |
Hi,
Can you file a JIRA for this at with details on the version
you used and a short test case we can reproduce this with (or if not a
test case, even a few detailed steps to running into this would help)?
On Tue, Jan 31, 2012 at 7:19 AM, ey-chih chow <eychih@hotmail.com> wrote:
> Hi,
>
> We got an issue with avro serialization/de-serialization when running a
> map-reduce job against avro data. The input schema of the job is union of
> two schemas. One of them is generated with Sqoop. When avro calls to
> resolveUnion(Schema union, Object datum) in GenericData.java, it compares
> the names of component schemas of the union with that of the schema of
> datum. However, the comparison alway fails because one of the name prepends
> with the corresponding namespace and the other not. We have a workaround
> for this. But we think this is a bug. Can somebody verify this and fix it?
> Thanks.
--
Harsh J
Customer Ops. Engineer, Cloudera | http://mail-archives.apache.org/mod_mbox/avro-user/201201.mbox/%3CCAOcnVr2Bw9a2krd5uO0613kVs-1rnryEzavqukb-jETZrX38nQ@mail.gmail.com%3E | CC-MAIN-2017-51 | refinedweb | 171 | 74.69 |
Odoo Help
Odoo is the world's easiest all-in-one management software. It includes hundreds of business apps:
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Conditionally apply Domain on a field
Is it posssible to apply a domain only when some condition is true otherwise the domain should not be applied in V7
For eg. in a many2one field to hr.employee, the manager should be able to see only the employee under him but someone from the hr department should be able to view all the employees in the view.
I solved the problem I couldn't find a regular way to do what i wanted. I feel this is a bit hackish way to achieve what i wanted; what i did was override the fields-view_get method and implemented what i wanted in that. here's a sample code of what i did, maybe it'll help other looking to implement similar functionality
def fields_view_get(self, cr, user, view_id=None, view_type='form', context=None, toolbar=False, submenu=False):
""" Overrides orm field_view_get. @return: Dictionary of Fields, arch and toolbar. """ res = {} res = super(employee_exit, self).fields_view_get(cr, user, view_id, view_type, context, toolbar=toolbar, submenu=submenu) hr_employee = self.pool.get('hr.employee') emp = hr_employee.search(cr, user, [('user_id', '=', user)])[0] logged_employee = hr_employee.browse(cr, user, emp) from lxml import etree doc=etree.XML(res['arch']) for node in doc.xpath("//field[@name='target_employee_id']"): if not logged_employee.department_id.name == "Human Resources": node.set('domain', "['&','|',('parent_id.user_id', '=', uid),('department_id.manager_id.user_id','=',uid),('user_id','!=',uid)]") elif logged_employee.department_id.manager_id.user_id.id==user: node.set('domain', "[('user_id','!=',uid)]") else: node.set('domain', "['&','&',('user_id','!=',uid),('user_id','!=',"+str(logged_employee.department_id.manager_id.user_id.id)+\ "),('user_id','!=',"+str(logged_employee.parent_id.user_id.id)+")]") res['arch']=etree.tostring(doc) return res
EDIT: I can't mark this as the answer as i don't have sufficient points. if somebody finds it useful and doesn't know of any better method please mark this as the answer so it may be visible to others in need at the top
Funny enough, the question and the example provided can have two different answers:
Is it possible to have a a "conditional" domain?
Yes, by building the domain in a smart way, using OR (
|) operators.
For example, on a particular Model having a
company_id field, you could use:
['|',('company_id','child_of',[user.company_id.id]),('company_id','=',False)]
Here the "child of" condition will only be enforced if the record's "company_id" has a value.
The manager should see only his employees, but hr department should see all
To easiest way to achieve this is to have two user Groups. The Managers group has a record rule to view only his employees and the HR manager group has a record rule to see all employees. You can find a similar example in the CRM app: there is a "Sales / See Own Leads" group and a "Sales / See All Leads" group.
Record rules apply to current record based on User attributes. You would need to know the Department to use for the current User, but AFAIK that info is not available in the User model. You would somehow need to have a
department_id in the User and then could create a record rule (or many2one domain) similar to:
['|',('department_id','child_of',[user.department_id.id]),(False,'=',user.department_id)]
Thanks, that was educational but i have a many2one field to hr.employee which is being displayed in the view obviously as a dropdown, now what i want is if the logged in user has department the HR then when he uses the drop down he should be able to see all the employees of the other departments and all the employees below him in HR Department, but if the logged in user is a not of the HR Department and uses the dropdown he should be able to see only the employees he the parent of. Also please explain in the above example which company_id do you mean the user.company_id or 'company_id'
Expanded the answer. The feature you need would ge a great addition to lp:openerp-hrms.
So in short its not posssible to get exactly what i need with exisiting functionality?
res.user doesnt have any field like department_id.... how is it possible to use this?....i have got error.....
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No one know how to do it? is it even possible? | https://www.odoo.com/forum/help-1/question/conditionally-apply-domain-on-a-field-25468 | CC-MAIN-2017-43 | refinedweb | 752 | 55.74 |
Can someone tell me what I'm doing wrong / missing?
import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner Scanner = new Scanner(System.in); double pi = 3.14; //your code goes here int r; r = Scanner.nextInt(); double perimeter = 2*pi*r; System.out.print(+ perimeter); } }
3/6/2021 12:54:39 AMGabriella Martinez
10 AnswersNew Answer
It's probably a naming collision. Your Scanner variable name is also Scanner. Try changing it to something else or at least change the first letter so that it is a lower case s instead of S.
Gabriella Martinez Here your solution
You have a misplaced "+" in your System.out.print()
Apollo-Roboto The + here is just a unary operator signifying that the number is positive (or * 1 rather) and makes no difference in the functionality of the program. Gabriella Martinez What is your issue with the expected output? The output is mostly correct, with the exception of the least significant bits. This part can be solved using formatting or rounding to cut those parts off. This has to do with the use of floating point numbers. If you want more accuracy in your result of the circumference then you should use the PI constant found in the Math class. double circumference = Math.PI * 2 * r; System.out.println(String.format("%.2f", circumference));
Your code in the post works fine for me when I copied it into the playground.
Wow that small of a change fixed it lol. I feel super dumb now. Thank you so much!
put scanner instead of Scanner so that: Scanner scanner... and r = scanner.nextInt();
i kept getting an error message stating, “Exception in thread “main,” and i wasnt sure what it meant. Im trying to use radius to find perimeter
This is what it's telling me: It also won’t accept it for the test cases. Weird! Thanks for the help.
Remember this for next time you ask a question. If you had included the error information in your post you would have gotten your answer much faster. Lol I just thought it was a typo, and that you were trying to run the code in the playground (which it works there just fine, shouldn't, but does), so I didn't pay it any mind and thought you were wondering about why the fractional part of the output was that way. | https://www.sololearn.com/Discuss/2715534/can-someone-tell-me-what-i-m-doing-wrong-missing/ | CC-MAIN-2021-17 | refinedweb | 401 | 75.4 |
Bugs item #1124861, was opened at 2005-02-17 17:23 Message generated for change (Comment added) made by astrand You can respond by visiting: Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Windows Group: Python 2.4 Status: Open Resolution: None Priority: 7 Private: No Submitted By: davids (davidschein) Assigned to: Nobody/Anonymous (nobody) Summary: subprocess fails on GetStdHandle in interactive GUI Initial Comment: Using the suprocess module from with IDLE or PyWindows, it appears that calls GetStdHandle (STD_<???>_HANDLE) returns None, which causes an error. (All appears fine on Linux, the standard Python command-line, and ipython.) For example: >>> import subprocess >>> p = subprocess.Popen("dir", stdout=subprocess.PIPE) Traceback (most recent call last): File "<pyshell#49>", line 1, in -toplevel- p = subprocess.Popen("dir", stdout=subprocess.PIPE) File "C:\Python24\lib\subprocess.py", line 545, in __init__ (p2cread, p2cwrite, File "C:\Python24\lib\subprocess.py", line 605, in _get_handles p2cread = self._make_inheritable(p2cread) File "C:\Python24\lib\subprocess.py", line 646, in _make_inheritable DUPLICATE_SAME_ACCESS) TypeError: an integer is required The error originates in the mswindows implementation of _get_handles. You need to set one of stdin, stdout, or strerr because the first line in the method is: if stdin == None and stdout == None and stderr == None: ...return (None, None, None, None, None, None) I added "if not handle: return GetCurrentProcess()" to _make_inheritable() as below and it worked. Of course, I really do not know what is going on, so I am letting go now... def _make_inheritable(self, handle): ..."""Return a duplicate of handle, which is inheritable""" ...if not handle: return GetCurrentProcess() ...return DuplicateHandle(GetCurrentProcess(), handle, ....................................GetCurrentProcess(), 0, 1, ....................................DUPLICATE_SAME_ACCESS) ---------------------------------------------------------------------- >Comment By: Peter Åstrand (astrand) Date: 2007-01-30 21:05 Message: Logged In: YES user_id=344921 Originator: NO Please review 1124861.3.patch. ---------------------------------------------------------------------- Comment By: Peter Åstrand (astrand) Date: 2007-01-30 21:04 Message: Logged In: YES user_id=344921 Originator: NO File Added: 1124861.3.patch ---------------------------------------------------------------------- Comment By: Peter Åstrand (astrand) Date: 2007-01-29 22:42 Message: Logged In: YES user_id=344921 Originator: NO Some ideas of possible solutions for this bug: 1) As Roger Upole suggests, throw an readable error when GetStdHandle fails. This would not really change much, besides of subprocess being a little less confusing. 2) Automatically create PIPEs for those handles that fails. The PIPE could either be left open or closed. A WriteFile in the child would get ERROR_BROKEN_PIPE, if the parent has closed it. Not as good as ERROR_INVALID_HANDLE, but pretty close. (Or should I say pretty closed? :-) 3) Try to attach the handles to a NUL device, as 1238747 suggests. 4) Hope for the best and actually pass invalid handles in startupinfo.hStdInput, startupinfo.hStdOutput, or startupinfo.hStdError. It would be nice if this was possible: If GetStdHandle fails in the current process, it makes sense that GetStdHandle will fail in the child as well. But, as far as I understand, it's not possible or safe to pass invalid handles in the startupinfo structure. Currently, I'm leaning towards solution 2), with closing the parents PIPE ends. ---------------------------------------------------------------------- Comment By: Peter Åstrand (astrand) Date: 2007-01-22 20:36 Message: Logged In: YES user_id=344921 Originator: NO The following bugs have been marked as duplicate of this bug: 1358527 1603907 1126208 1238747 ---------------------------------------------------------------------- Comment By: craig (codecraig) Date: 2006-10-13 17:54 Message: Logged In: YES user_id=1258995 On windows, this seems to work from subprocess import * p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE) ....in some cases (depending on what command you are executing, a command prompt window may appear). Do not show a window use this... import win32con p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, creationflags=win32con.CREATE_NO_WINDOW) ...google for Microsoft Process Creation Flags for more info ---------------------------------------------------------------------- Comment By: Steven Bethard (bediviere) Date: 2005-09-26 16:53 Message: Logged In: YES user_id=945502 This issue was discussed on comp.lang.python[1] and Roger Upole suggested: """ Basically, gui apps like VS don't have a console, so GetStdHandle returns 0. _subprocess.GetStdHandle returns None if the handle is 0, which gives the original error. Pywin32 just returns the 0, so the process gets one step further but still hits the above error. Subprocess.py should probably check the result of GetStdHandle for None (or 0) and throw a readable error that says something like "No standard handle available, you must specify one" """ [1] ---------------------------------------------------------------------- Comment By: Steven Bethard (bediviere) Date: 2005-08-13 22:37 Message: Logged In: YES user_id=945502 I ran into a similar problem in Ellogon () which interfaces with Python through tclpython (). My current workaround is to always set all of stdin, stdout, and stderr to subprocess.PIPE. I never use the stderr pipe, but at least this keeps the broken GetStdHandle calls from happening. Looking at the code, I kinda think the fix should be:: if handle is None: return handle return DuplicateHandle(GetCurrentProcess(), ... where if handle is None, it stays None. But I'm also probably in over my head here. ---------------------------------------------------------------------- You can respond by visiting: | https://mail.python.org/pipermail/python-bugs-list/2007-January/036988.html | CC-MAIN-2014-15 | refinedweb | 856 | 55.84 |
I’m attempting to compile a hello world program on the new Apple Silicon.
I’m in Visual Studio Code running under emulation with Rosetta 2.
This is my code:
#include <iostream> int main() { std::cout << "Hello World!"; return 0; }
I get the error:[Running] cd "/Users/jacob/Documents/VS Code/" && g++ helloWorld.cpp -o helloWorld && "/Users/jacob/Documents/VS Code/"helloWorld
helloWorld.cpp:1:17: warning: extra tokens at end of #include directive [-Wextra-tokens] #include ;
^
//
helloWorld.cpp:1:10: fatal error: ‘stdio’ file not found
#include ;
^~~~~~~
1 warning and 1 error generated. [Done] exited with code=1 in 0.072 seconds
I think the key here is that g++ is the underlying compiler and that stdio cannot be found. Maybe the answer here is to determine if g++ is functional, or how to make g++ functional, but any help is much appreciated!
Source: Windows Questions C++ | https://windowsquestions.com/2020/11/30/cannot-find-stdio-h-on-m1-mac-apple-silicon/ | CC-MAIN-2021-39 | refinedweb | 148 | 51.34 |
is there an easy way to get the main windows handle(it only uses one), by just knowing the programs filename?
This is a discussion on Easiest what to get a windows handle with just the filename? within the Windows Programming forums, part of the Platform Specific Boards category; is there an easy way to get the main windows handle(it only uses one), by just knowing the programs filename?...
is there an easy way to get the main windows handle(it only uses one), by just knowing the programs filename?
ADVISORY: This users posts are rated CP-MA, for Mature Audiences only.
Weird request...!!!
I had a few tries at this, and it appears there would be more than 1 way to do this.....
GetWindowModuleFileName() looked like a winner, but for some reason I couldnt get it to do what I wanted.....Also I realised my old version of the SDK is starting to become a pain in the arse......but that's another story....
Anyway...not perfect by a long shot, but it seems to produce something....
This uses the PSAPI.dll which is an addon to WINNT (oh...you need NT at least for this prog as it deals with processes and stuff - there's a shock!This uses the PSAPI.dll which is an addon to WINNT (oh...you need NT at least for this prog as it deals with processes and stuff - there's a shock!Code:#include <windows.h> #include <iostream> #include <cstring> using namespace std; typedef DWORD (WINAPI *GMFNE)(HANDLE,HMODULE,LPSTR,DWORD); /*My PSAPI lib seems to be faulty......so I had to link to GetModuleFileNameEx at runtime*/ char exefile[] = "C:\\WINNT\\System32\\calc.exe"; //The exe of your choice.... BOOL CALLBACK EnumWindowsProc(HWND hwnd,LPARAM lParam){ GMFNE lpGMFNE = (GMFNE)lParam; /*Entry point to the GetModuleFileNameEx func*/ DWORD dwPID,//Process ID dwBytes;//Bytes returned HANDLE hProc;//Process Handle HMODULE hMod;//Module Handle char buff[MAX_PATH];//Buffer hMod = (HMODULE)GetWindowLong(hwnd,GWL_HINSTANCE); //Get the module for the window GetWindowThreadProcessId(hwnd,&dwPID); //Also the Process ID hProc = OpenProcess(PROCESS_ALL_ACCESS,FALSE,dwPID); //Now use that ID to get Process handle if(hProc && hMod){ dwBytes = lpGMFNE(hProc,hMod,buff,MAX_PATH); //GetModuleFileNameEx if(dwBytes){ buff[dwBytes] = NULL; if(!strcmp(exefile,buff))//Is it from calc.exe? cout << "Found HWND - " << hwnd << endl; } CloseHandle(hProc);//Close } return TRUE; } int main(void){ HMODULE hMod; GMFNE lpGMFNE; hMod = LoadLibrary("PSAPI.dll"); if(!hMod){ cout << "PSAPI.dll not present"; return 1; } lpGMFNE = (GMFNE)GetProcAddress(hMod,"GetModuleFileNameExA"); if(!lpGMFNE){ cout << "Could not locate procedure"; FreeLibrary(hMod); return 1; } EnumWindows((WNDENUMPROC)EnumWindowsProc,(LPARAM)lpGMFNE); FreeLibrary(hMod); return 0; }
)...this dll is usually in the system32 dir as loads of apps ship it & install it.....)...this dll is usually in the system32 dir as loads of apps ship it & install it.....
The code is messy, and there is probably a better way, but it might do with some tidying up.
Hmmm... how does the program know its own filename?
Did you know that any windows process has a handle to itself? It's easy enough to get that:
You don't even need to know the filename.You don't even need to know the filename.Code:char szFileName[MAX_PATH]; HINSTANCE hInstance = GetModuleHandle(NULL); GetModuleFileName(hInstance, szFileName, MAX_PATH); MessageBox(hwnd, szFileName, "This program is:", MB_OK | MB_ICONINFORMATION);
This code here actually finds the program pathway too but it does it by first getting the handle, i.e.
HINSTANCE hInstance = GetModuleHandle(NULL);
Tell me how that goes.
thanks fordy, looks good.
i'll try it soon.
the only real change think would help
is using strstr() to find the filename without the path since that can change. | http://cboard.cprogramming.com/windows-programming/20485-easiest-what-get-windows-handle-just-filename.html | CC-MAIN-2015-32 | refinedweb | 610 | 57.16 |
ASP.NET - Quick Guide
What is ASP.Net?
ASP.Net is a web development platform, which provides a programming model, a comprehensive software infrastructure and various services required to build up robust web application for PC, as well as mobile devices.
ASP.Net is a part of Microsoft .Net platform. ASP.Net applications could be written in either of the following languages:
C#
Visual Basic .Net
Jscript
J#.
ASP.Net Environment Setup:
The key development tool for building ASP.Net applications and front ends is Visual Studio.
Visual Studio is an integrated development environment for writing, compiling and debugging the code. It provides a complete set of development tools for building ASP.Net web applications, web services, desktop applications and mobile applications. form's works.
A typical ASP.Net application consists of many items: the web content files (.aspx), source files (e.g., the .cs files), assemblies (e.g., the .dll files and .exe files), data source files (e.g., .mdb files), references, icons, user controls and miscellaneous other files and folders. All these files that make up the website are contained in a Solution.
Typically a project contains the following content files:
Page file (.aspx)
User control (.ascx)
Web service (.asmx)
Master page (.master)
Website configuration file (.config)
The application is run by selecting either Start or Start Without Debugging from the Debug menu, or by pressing F5 or Ctrl-F5. The program is built i.e.: When user makes a request for accessing application resource, a page. Browser sends this request to the web server and it request passes through several stages before server response gets back.
Page Life Cycle:.
ASP.Net Example:
An ASP.Net page is also a server side file saved with the .aspx extension. It is modular in nature and can be divided into the following core sections:
Page directives
Code Section
Page Layout
Page directives:
The page directives set up the environments for the page to run. The @Page directive defines page-specific attributes used by the ASP.Net page parser and compiler. Page directives specify how the page should be processed, and which assumptions are to be taken about the page.
It allows importing namespaces, loading assemblies and registering new controls with custom tag names and namespace prefixes. We will discuss all of these concepts in due time.
Code Section:
The code section provides the handlers for the page and control events along with other functions required. We mentioned that, ASP.Net follows an object model. Now, these objects raises events when something happens on the user interface, like a user clicks a button or moves the cursor. How these events should be handled? That code is provided in the event handlers of the controls, which pafe's root directory. Generally it is c:\inetput\wwwroot. Open the file from the browser to run it and it should generate following result:
Using Visual Studio IDE::
<%@>
Run the example either from Debug menu, or by pressing Ctrl-F5 or by right clicking on the design view and choosing 'View in Browser' from the popup menu. This should generate following result:
| http://www.tutorialspoint.com/cgi-bin/printversion.cgi?tutorial=asp.net&file=asp.net_quick_guide.htm | CC-MAIN-2014-15 | refinedweb | 517 | 60.31 |
- Author:
- mhalle
- Posted:
- March 30, 2008
- Language:
- Python
- Version:
- .96
- filter ajax json database query
- Score:
- 2 (after 2 ratings) can't be created on the client side or stored.
build_query_filter_from_spec() is a function that solves this problem by describing query filters using a vaguely LISP-like syntax. Query filters consist of lists with the filter operator name first, and arguments following. Complicated query filters can be composed by nesting descriptions. Read the doc string for more information.
To use this function in an AJAX application, construct a filter description in JavaScript on the client, serialize it to JSON, and send it over the wire using POST. On the server side, do something like:
from django.utils import simplejson
filterString = request.POST.get('filter', '[]')
filterSpec = simplejson.loads(filterString)
q = build_query_filter_from_spec(filterSpec)
result = Thing.objects.filter(q)
You could also use this technique to serialize/marshall a query and store it in a database.
Please login first before commenting. | https://djangosnippets.org/snippets/676/ | CC-MAIN-2017-34 | refinedweb | 158 | 51.65 |
Windows C++ installations are monolithic, i.e. the user has to download the installation, run it, and then manage it by himself/herself, or call the system administrator which will have to install the application on each computer, along with all its dependencies, either by visiting or logging remotely. But this is usually done only on LANs or VPNs, and not on WANs.
In the Unix world, the need for automatic installation and updating of applications is taken care by package management systems, but the downloading and updating of individual components of an application is not done lazily and in the background. Granted, Unix provides good tools that can automate the job, but it requires a fair amount of work in order to work properly.
What I would like to see, as part of the POCO project, is a set of libraries and modules that allow me to:
- write my application as one small executable and a set of DLLs.
- post the executable and the DLLs to a server.
- tell the user where to download the executable from.
From that point on, the user downloads the executable, and the following happens:
- the user puts the executable in any folder he/she desires.
- the user runs the executable normally, i.e. by double-clicking it from the GUI or launching it from the command line.
- the executable downloads and installs the main DLL of the program automatically, and then loads it and runs it.
- each time a DLL is requested to be loaded in the application space for the first time, the system automatically downloads and installs the appropriate DLL, if a new version is available in the server; otherwise, the local version is used.
- the DLL maintenance mechanism can be extended to other types of data as well (pictures, sounds, etc).
While this capability does not strictly belong to POCO, POCO contains all the tools required for this code and data management (cryptography, servers, networking, etc).
Here is how I do envisage the code. For example, let's say I wish to write an application that accepts the user's name and prints 'hello world'. My main function would be:
- Code: Select all
#include "HelloWorld.hpp"
RemoteModule<HelloWorld> helloWorld("192.168.1.15", 80);
int main() {
string name = helloWorld.inputName();
helloWorld.greetUser(name);
}
The HelloWorld.hpp header would contain the interface for the implementation:
- Code: Select all
class HelloWorld {
public:
virtual ~HelloWorld() {}
virtual string inputName() = 0;
virtual void greetUser(string name) = 0;
};
Suppose that initially, I do not need a GUI. I can then write an instance of HelloWorld that uses the command line:
- Code: Select all
class ConsoleHelloWorld : public HelloWorld {
public:
virtual string inputName() {
string str;
cin >> str;
return str;
}
virtual void greetUser(string name) {
cout << "hello " << name "!\n";
}
};
Let's say a user downloads the executable. Then, the executable runs, the system downloads the main DLL, the DLL is loaded and executed, as specified by the code.
Suppose now I want to change the class to use a GUI. I then write a new DLL with this implementation:
- Code: Select all
#include "GUILibrary.hpp"
RemoteModule<GUILibrary> guiLibrary("");
class ConsoleHelloWorld : public HelloWorld {
public:
virtual string inputName() {
SharedPtr<InputDialog> dialog = guiLibrary.new_<InputDialog>("Name:");
dialog->doModal();
return dialog->inputValue();
}
virtual void greetUser(string name) {
guiLibrary::MessageBox::messageBox("Hello " + name + "!");
}
};
With this system, I can post the new DLL in the server at address 192.168.1.15, and the next time the user runs the application, the following happens: the system sees that a new DLL is available from the specific server; the new DLL is downloaded and installed; the new DLL is loaded into the process and run; the user now sees the update.
So, what do you think? such a system could solve many issues. The above text only describes the main idea, of course.
POCO itself could be downloaded and managed via the same system. Such a system would attract a lot of people to POCO.
Thank you for your attention to this lengthy and unconventional post. | http://pocoproject.org/forum/viewtopic.php?f=8&t=5195&p=8372 | CC-MAIN-2014-10 | refinedweb | 670 | 54.02 |
I am trying to do something when a boolean from another function is set to "True". I tried using return(variable) but when it comes to the function that asks for the bool it always says False. I took a look here before asking this because I felt like this seems to be really basic stuff. But i couldn't find anything usefull. I hope someone can help me with this.
Here is my code.
x = 0
bool = False
def functionA(x,bool):
if x is 0:
bool = True
def functionB(bool):
print bool
if bool is True:
print "Halleluhja"
functionA(x,bool)
functionB(bool)
print x, bool
Sticking to how you've written your code, you have two options. Option 1 is to use a global variable, making sure you include the
global declaration in functions where you want to modify it:
x = 0 bool = False def functionA(x): global bool if x is 0: bool = True def functionB(): print bool if bool is True: print "Halleluhja" functionA(x) functionB() print x, bool
Option 2 (preferred) is to actually return things so that they can be passed elsewhere:
x = 0 def functionA(x): if x is 0: return True else: return False def functionB(bool): print bool if bool is True: print "Halleluhja" bool = functionA(x) functionB(bool) print x, bool
Other than that, don't use the name
bool, use
x == 0 rather than
x is 0,
functionA can be written as just
return x == 0, use
if bool: rather than
if bool is True:, and use
snake_case (
function_a) rather than
camelCase. | https://codedump.io/share/R6sRwMC2mvs4/1/check-boolean-from-another-function | CC-MAIN-2017-34 | refinedweb | 264 | 65.39 |
)
More...
CS508 Final Subjective (12-08-2017)
Q)The list is one of the original LISP data types, based on the concept of List in LISP, answer the following parts.
a) Write a function in LISP that creates a list by taking following three arguments as its elements.
Foo, Bar, Jack
b) Create a list that inserts symbol ‘z’ at the front of list L. (5marks)
Q. (5marks)
Q)There is usually no need to convert between numbers and strings in PHP. Numbers and strings are interchangeable.
a)Write the resultant output after the execution of following php statements.
$foo = 1 + "11 Rabbits";
$foo = "11.0 rabbits " + 1;
b) Mention the advantages and disadvantages of using strings in numeric expressions.
(3 marks)
Q)How many ways can be used to write foreach statement using php.Write syntax in each case. (3 marks)
Q)What will be the output of the following C# code?
using System;
public class HelloWorld
{
public static void Main()
{
string s1 = "hello";
string s2 = s1;
s1 = “world”;
Console . WriteLine(s1);
}
}
Q)We have a java program in which a variable named “LongVar” of type long is declared and used. Suppose this program runs on two machines; one is having Intel Pentium I processor and the other is having Intel Core 2 Duo. How many bytes of memory “LongVar” will consume on each machine? Give reasons to support your answer.
Q)From the given code snippet in C#, find out whether aliasing problem will arise or not? Justify your answer with valid reasons. (5marks)
object studentcs = new object();
studentcs.id = 123;
object studentbba = studentcs;
studentbba.id = 204;
paper easy tha ya tough???????
jese questions aarhe hain, tough lag rha hy
quiz kaha se aye thye i means k past papers se aye ya ni
Q)From the given code snippet in C#, find out whether aliasing problem will arise or not? Justify your answer with valid reasons. (5marks)
object studentcs = new object();
studentcs.id = 123;
object studentbba = studentcs;
studentbba.id = 204;
is question ka answer kia bnta ha :P
MCQz kis file se aye thay please send kr den...
bht tough paper thaa
is file mai say 8 mcqs ay thy zain nasar ki file
ya downlod ni ho rahi
mail kar dyn plz ya papers
© 2020 Created by + M.Tariq Malik.
Promote Us | Report an Issue | Privacy Policy | Terms of Service | https://vustudents.ning.com/forum/topics/cs508-current-final-term-papers-past-final-term-papers-at-one-2?groupUrl=cs508modernprogramminglanguages&commentId=3783342%3AComment%3A5882467&groupId=3783342%3AGroup%3A60032 | CC-MAIN-2020-16 | refinedweb | 394 | 74.79 |
Hydrological and meteorological timeseries
Project description
htimeseries - Hydrological and meteorological time series
This module provides the HTimeseries class, which is a layer on top of pandas, offering a little more functionality.
Introduction
from htimeseries import HTimeseries ts = HTimeseries()
This creates a HTimeseries object, whose data attribute is a pandas time series or dataframe with a datetime index. Besides data, it can have other attributes which serve as the time series’ metadata. There are also several utility methods described below.
HTimeseries objects
HTimeseries(data=None, format=None, start_date=None, end_date=None)
Creates a HTimeseries object. data can be a pandas time series or dataframe indexed by datetime or a file-like object. If it is a pandas object, it becomes the value of the data attribute and the rest of the keyword arguments are ignored.
The data attribute should be a dataframe with two columns (besides date): value and flags. However, in this version, HTimeseries does not enforce that. A good idea is to create an empty HTimeseries object with HTimeseries(), and then proceed to fill in its data attribute. This ensures that the dataframe will have the right columns and dtypes.
If the data argument is a filelike object, the time series is read from it. There must be no newline translation in data (open it with open(..., newline='\n'). If start_date and end_date are specified, it skips rows outside the range.
The contents of the filelike object can be in text format or file format (see “formats” below). This usually auto-detected, but a specific format can be specified with the format parameter. If reading in text format, the returned object just has the data attribute set. If reading in file format , the returned object also has attributes unit, title, comment, timezone, time_step, interval_type, variable, precision and location. For the meaning of these attributes, see section “File format” below.
These attributes are purely informational. In particular, time_step and the other time-step-related attributes don’t necessarily mean that the pandas object will have a related time step (also called “frequency”). In fact, raw time series may be irregular but actually have a time step. For example, a ten-minute time series might end in :10, :20, etc., but at some point there might be an irregularity and it could continue with :31, :41, etc. Strictly speaking, such a time series has an irregular step. However, when stored in a database, specifying that its time step is ten minutes (because that’s what it is, ten minutes with irregularities) can help people who browse or search the database contents.
The location attribute is a dictionary that has items abscissa, ordinate, srid, altitude, and asrid.
.write(f, format=HTimeseries.TEXT, version=None)
Writes the time series to filelike object f. In accordance with the formats described below, time series are written using the CR-LF sequence to terminate lines. Care should be taken that f, or any subsequent operations on f, do not perform text translation; otherwise it may result in lines being terminated with CR-CR-LF. If f is a file, it should have been opened in binary mode.
version is ignored unless format=HTimeseries.FILE. The default version is latest.
While writing, the value of the precision attribute is taken into account.
TzinfoFromString objects
from htimeseries imort TzinfoFromString atzinfo = TzinfoFromString("EET (UTC+0200)")
TzinfoFromString is a utility that creates and returns a tzinfo object from a string formatted as “+0000” or as “XXX (+0000)” or as “XXX (UTC+0000)” (TzinfoFromString is actually a tzinfo subclass). Its purpose is to read the contents of the timezone parameter of the file format (described below).
Formats
There are two formats: the text format is generic text format, without metadata; the file format is like the text format, but additionally contains headers with metadata.
Text format
The text format for a time series is us-ascii, one line per record, like this:
2006-12-23 18:34,18.2,RANGE
The three fields are comma-separated and must always exist. In the date field, the time may be missing. The character that separates the date from the time may be either a space or a lower case t, or a capital T (this module produces text format using a space as date separator, but can read text format that uses t or T). The second field always uses a dot as the decimal separator and may be empty. The third field is usually empty but may contain a list of space-separated flags. The line separator should be the CR-LF sequence used in MS-DOS and Windows systems. Code that produces text format should always use CR-LF to end lines, but code that reads text format should be able to also read lines that end in LF only, as well as CR-CR-LF (for reasons explained in the write() function above).
In order to improve performance in file writes, the maximum length of each time series record line is limited to 255 characters.
Flags should be encoded in ASCII; there must be no characters with code greater than 127.
File format
The file format is like this:
Version=2 Title=My timeseries Unit=°C 2006-12-23 18:34,18.2,RANGE 2006-12-23 18:44,18.3,
In other words, the file format consists of a header that specifies parameters in the form Parameter=Value, followed by a blank line, followed by the timeseries in text format. The same conventions for line terminators apply here as for the text format. The encoding of the header section is UTF-8.
Client and server software should recognize UTF-8 files with or without UTF-8 BOM (Byte Order Mark) in the begining of file. Writes may or may not include the BOM, according OS. (Usually Windows software attaches the BOM at the beginning of the file).
Parameter names are case insensitive. There may be white space on either side of the equal sign, which is ignored. Trailing white space on the line is also ignored. A second equal sign is considered to be part of the value. The value cannot contain a newline, but there is a way to have multi-lined parameters explained in the Comment parameter below. All parameters except Version are optional: either the value can be blank or the entire Parameter=Value can be missing; the only exception is the Comment parameter.
The parameters available are:
- Version
There are four versions:
- Version 1 files are long obsolete. They did not have a header section.
- Version 2 files must have Version=2 as the first line of the file. All other parameters are optional. The file may not contain unrecognized parameters; software reading files with unrecognized parameters may raise an error.
- Version 3 files do not have the Version parameter. At least one of the other parameters must be present. Unrecognized parameters are ignored when reading. The old deprecated parameter names Nominal_offset and Actual_offset are used instead of the newer (but also deprecated) ones Timestamp_rounding and Timestamp_offset.
- Version 4 files are the same as Version 3, except for the names of the parameters Timestamp_rounding and Timestamp_offset.
- Version 5 files are the same as Version 4, except that Timestamp_rounding and Timestamp_offset do not exist, and Time_step is in a different format (see below).
- Unit
- A symbol for the measurement unit, like °C or mm.
- Count
- The number of records in the time series. If present, it need not be exact; it can be an estimate. Its primary purpose is to enable progress indicators in software that takes time to read large time series files. In order to determine the actual number of records, the records need to be counted.
- Title
- A title for the time series.
- Comment
A multiline comment for the time series. Multiline comments are stored by specifying multiple adjacent Comment parameters, like this:
Comment=This timeseries is extremely important Comment=because the comment that describes it Comment=spans five lines. Comment= Comment=These five lines form two paragraphs.
The Comment parameter is the only parameter where a blank value is significant and indicates an empty line, as can be seen in the example above.
- Timezone
The time zone of the timestamps, in the format {XXX} (UTC{+HHmm}), where XXX is a time zone name and +HHmm is the offset from UTC. Examples are EET (UTC+0200) and VST (UTC-0430).
The TzinfoFromString utility (described above) can be used to convert this string to a tzinfo object.
- Time_step
In version 5, a pandas “frequency” string such as 10min (10 minutes), H (hour), or 2M (two months). If missing or empty, the time series is without time step.
Up to version 4, a comma-separated pair of integers; the number of minutes and months in the time step (one of the two must be zero).
When reading from version 4 or earlier, the pair of integers is automatically converted to a pandas “frequency” string, so the time_step attribute of an HTimeseries object is always a pandas “frequency” string. Likewise, when writing to a version 4 or earlier file, the pandas “frequency” string is automatically converted to the pair of integers.
- Timestamp_rounding
Deprecated. It might be found in old files, Version 4 or earlier, but htimeseries will ignore it when reading and will never write it.
A comma-separated pair of integers indicating the number of minutes and months that must be added to a round timestamp to get to the nominal timestamp. For example, if an hourly time series has timestamps that end in :13, such as 01:13, 02:13, etc., then its rounding is 13 minutes, 0 months, i.e., (13, 0). Monthly time series normally have a nominal timestamp of (0, 0), the timestamps usually being of the form 2008-02-01 00:00, meaning “February 2008” and usually rendered by application software as “Feb 2008” or “2008-02”. Annual timestamps have a nominal timestamp which normally has 0 minutes, but may have nonzero months; for example, a common rounding in Greece is 9 months (0=January), which means that an annual timestamp is of the form 2008-10-01 00:00, normally rendered by application software as 2008-2009, and denoting the hydrological year 2008-2009.
timestamp_rounding may be None, meaning that the timestamps can be irregular.
Timestamp_rounding is named differently in older versions. See the Version parameter above for more information.
- Timestamp_offset
Deprecated. It might be found in old files, Version 4 or earlier, but htimeseries will ignore it when reading and will never write it.
A comma-separated pair of integers indicating the number of minutes and months that must be added to the nominal timestamp to get to the actual timestamp. The timestamp offset for small time steps, such as up to daily, is usually zero, except if the nominal timestamp is the beginning of an interval, in which case the timestamp offset is equal to the length of the time step, so that the actual timestamp is the end of the interval. For monthly and annual time steps, the timestamp offset is usually 1 and 12 months respectively. For a monthly time series, a timestamp offset of (-475, 1) means that 2003-11-01 00:00 (often rendered as 2003-11) denotes the interval 2003-10-31 18:05 to 2003-11-30 18:05.
Timestamp_offset is named differently in older versions. See the Version parameter above for more information.
- Interval_type
- Has one of the values sum, average, maximum, minimum, and vector_average. If absent it means that the time series values are instantaneous, they do not refer to intervals.
- Variable
- A textual description of the variable, such as Temperature or Precipitation.
- Precision
- The precision of the time series values, in number of decimal digits after the decimal separator. It can be negative; for example, a precision of -2 indicates values accurate to the hundred, such as 100, 200, 300 etc.
- Location, Altitude
- (Versions 3 and later.) Location is three numbers, space-separated: abscissa, ordinate, and EPSG SRID. Altitude is one or two space-separated numbers: the altitude and the EPSG SRID for altitude. The altitude SRID may be omitted.
History
2.0.2 (2020-01-05)
- Default version when writing file is now latest.
2.0.1 (2020-01-04)
- Fixed error when the time step was empty.
2.0.0 (2020-01-04)
- Changed the way the time step is specified. Instead of “minutes,months”, it is now a pandas “frequency” offset specification such as “5min” or “3M”.
- The timestamp_offset and timestamp_rounding parameters have been abolished.
1.1.2 (2019-07-18)
- Fixed some altitude-related bugs: 1) It would crash when trying to read a file that specified altitude but not location; 2) it wouldn’t write altitude to the file it the altitude was zero.
1.1.1 (2019-06-12)
- Fixed crash when Timestamp_rounding=None or Timestamp_offset=None.
1.1.0 (2019-06-08)
- Added TzinfoFromString utility (moved in here from pthelma).
1.0.1 (2019-06-06)
- Fixed error in the README (which prevented 1.0.0 from being uploaded to PyPi).
1.0.0 (2019-06-06)
- API change: .read() is gone, now we use a single overloaded constructor; either HTimeseries() or HTimeseries(dataframe) or HTimeseries(filelike).
- The columns and dtypes of .data are now standardized and properly created even for empty objects (created with HTimeseries()).
0.2.0 (2019-04-09)
- Auto detect format when reading a file
0.1.0 (2019-01-14)
- Initial release
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages. | https://pypi.org/project/htimeseries/2.0.2/ | CC-MAIN-2021-25 | refinedweb | 2,275 | 55.13 |
Fix...
Searching the web I discovered a couple of hints at what I had to do:
- Philipp "philiKON" von Weitershausen mentioning in this mail on the zope-cmf list that "you just need to do zope.component.provideAdapter(zope.traversing.adapters.DefaultTraversabl e)" which might be immediately comprehensible to someone who does Zope 3 stuff. philiKON explained to me on #zope that I would only have to add this line... which is not exactly correct.
- Łukasz Łakomy has a nice writeup about fixing this mess, but unfortunately he uses a test setup that is different from the usual ZopeTestCase (or at least different from what I'm used to). Nonetheless this is what helped me in the end.
- At some point I thought the solution would be to go to use zope.testbrowser, cuz "it's the new way, baby", but when I got it working following more or less Martin Aspeli's writeup on plone.org (also note the very important last comment about _p_jar), I got the same error.
In the end I had to combine philiKON's basic line, with the imports stolen from Łukasz, then I brewed it up into the form of Martin's setup (but changed to a more "normal" test setup).
Before I go through the solution in detail, I want to deliver a little rant to the Zope developers: I'm all for building modern stuff, modern programming paradigms, less boilerplate code, code reuse, etc. But (you knew there was a "but" coming) if the new stuff breaks existing code and the solution is just to copy and paste some boilerplate code that I don't even have to understand and that has not a snowball-in-hell chance to ever need to be changed / adjusted / customized, then... this new code stuff of yours just [choose your prefered expletive here] and should be considered broken.
The copy+pasted fix I'm applying here should probably be put into 2.10's ZopeTestCase itself, because then I wouldn't have the situation that my code works with only either 2.9 or 2.10 - I could leave my code alone and it would work on both Zopes (well, if I hadn't chosen to go with zope.testbrowser which isn't in 2.9's Five). But is this really the result of shiny new Interfaces, and IThis and IThat, that I have to copy+paste some blabla-code somewhere? End of rant.
So, let's go through the setup:
import unittest import doctest from Testing import ZopeTestCase ZopeTestCase.installProduct('ZCatalog') ZopeTestCase.installProduct('ZWiki') # ================== add these ======================== # imports copied from Lukasz mostly try: from zope import traversing, component, interface except ImportError: print '--------------------------------------------' print 'Functional tests will only run in Zope 2.10+' print '--------------------------------------------' raise from zope.traversing.adapters import DefaultTraversable from zope.traversing.interfaces import ITraversable from zope.component import provideAdapter from zope import interface from zope.interface import implements # ================== back to normal setup ============= class TestZWikiFunctional(ZopeTestCase.FunctionalTestCase): """ Testing browser paths through ZWiki. """ # ================== add these ======================== implements(ITraversable) def beforeSetUp(self): super(ZopeTestCase.FunctionalTestCase, self).beforeSetUp() component.provideAdapter( \ traversing.adapters.DefaultTraversable, \ (interface.Interface,),ITraversable) # ================== till here ======================== def testSomething(self): # This is here, because otherwise beforeSetUp wouldn't be run # it's only necessary because all my tests are in the # FunctionalDocFileSuite - which is added afterwards pass # old-style functional tests would go here def test_suite(): suite = unittest.makeSuite(TestZWikiFunctional) # the following is only when you go with zope.testbrowser tests: suite.addTest(ZopeTestCase.FunctionalDocFileSuite( 'functional.txt', package='Products.ZWiki', optionflags=doctest.REPORT_ONLY_FIRST_FAILURE | doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS)) return suite if __name__ == "__main__": unittest.main(defaultTest='test_suite')
So, if I count this right, I have to add about 10 lines of boilerplate, never to be changed code to get Functional tests running on Zope 2.10 again. This seems to be only if your Functional tests depend on Page Templates - but of course which Functional tests wouldn't depend on Page Templates?
The end result (the complete tests with the files functional.txt and Functional_tests.py) will hopefully soon turn up in ZWiki source code, for the moment these links point to my private repo.
As a final note I want to say that I really enjoyed working with zope.testbrowser. It's fun to write tests like that, even though mine aren't perfect yet. | http://betabug.ch/blogs/ch-athens/743 | CC-MAIN-2018-05 | refinedweb | 719 | 55.34 |
We are about to switch to a new forum software. Until then we have removed the registration on this forum.
Hi everyone,
I want to learn to write processing code in other IDEs like Eclipse or Netbeans (thereafter IDE). To learn it I try to work backward by running and study processing application exported java file (let's call it
RainGame.java) inside other IDEs.
I try to run the java file directly inside IDE, it works ( imported core.jar of course); then I cut the following code from RainGame.java and copied it into a new class named
Main, and then run the main method of Main class, it still works:
import processing.core.*; public class Main extends PApplet{ static public void main(String[] passedArgs) { String[] appletArgs = new String[] { "exercise_10_04_improved_rain_game" }; if (passedArgs != null) { PApplet.main(concat(appletArgs, passedArgs)); } else { PApplet.main(appletArgs); } } }
However, when I tried to cut three classes inside
RainGame.java out and copied them into three class files named
Catcher,
Drop,
Timer, and then call main method in Main class again, but they didn't work. The three classes are wrapped as following:
import processing.core.*; public class Catcher extends PApplet { .... } import processing.core.*; public class Drop extends PApplet { ... } import processing.core.*; public class Timer extends PApplet { ... }
My Question: why they don't work anymore? I wonder it is due to the mechanism of main method and the use of
passedArgs and
appletArgs, but I have no idea how they work and I could not find anything useful online to figure it out.
Thanks for your help
Answers
What exactly do you mean when you say they don't work? Do you get an error? Unexpected behavior? Something else?
@KevinWorkman Thanks and here are the errors:
@GoToLoop thanks. Though I found one post which seemed closed related, it looked a little too advanced compared with my problem at hand. So I still couldn't figure out by reading those posts. Would you explain in a simpler way at your convenience? Thanks
I found the API for main method
Now, I guess what troubles me the most is what exactly are the
args, what they are for, and how to use them in the main method?
Thanks(java.lang.String, java.lang.String[])
You need to modify the
public void static mainmethod for each class e.g.
The
public void static mainmethod defines the starting point for program execution. That means you usually have just one
mainmethod per application.
Personally I would avoid calling a class Main as it can cause confusion. ;)
Just an observation: Saying something like
RainGame.class.getName()is completely verbose & redundant.
A simple & direct "RainGame" is the way to go! ;)
And rather than: L-)
This overloaded main() "igniter" is more direct & concise: $-)
You might want to rethink that observation since it is wrong ;)
The OP is asking about writing sketches in Eclipse and Netbeans which both have the facility to refactor-rename classes etc. In my example changing the class name will also change the statement inside the main method. In your example the user would have to remember to change the "RainGame" string.
Verbosity is not always undesirable :)
Here's a nice couple of quotes for @GoToLoop I saw in Haverbeke's Eloquent Javascript; both of which made me think of his coding style :P
This one's good as well:
@blindfish, those quotes you've posted above and that
RainGame.class.getName()"pattern" got nothing to do w/ ea. other at all!
As @quark had already explained, that is an advanced refactoring facility provided by advanced IDEs.
It's got nothing to do w/ clarity nor it is something provided by the Java language itself! 8-|
Typing in "RainGame" is both clearer and faster for the point-of-view of Java language alone! ~O)
Actually for beginners,
RainGame.class.getName()is a completely obscure statement! 8-}
@GoToLoop: Sorry - I did indeed stray well off topic :\"> - but those quotes followed nicely from @quark's "Verbosity is not always undesirable"... O:-)
@quark and @GoToLoop thanks a lot!
I tried the following options: 1. giving each class a
mainmethod; 2. only give main method to
RainGameclass and run from there; however, neither works. Maybe it is due to my misunderstanding of @quark's answer.
I have pasted the full code below. The application I call it CatchRainGame which consists of five classes: 1.
Mainclass only contains the main method for the application; 2.
RainGameclass contains global variables,
settings(),
setup(),
draw()and etc.; 3.
Dropclass is responsible for creating rain drop object; 4.
Timerfor counting; 5.
Catcherclass is for displaying a catcher object to catch rain drop.
My intention is to run the application from the
mainmethod of
Mainclass. So, I would imagine there is only one main method as @quark suggested and I want the only
main methodin a seperated class
Main, away from
RainGame,
Drop,
Timer,
Catcherclasses.
What exactly should I do to the codes below? Thanks
The original code was from a book example from Learning Processing by Daniel Shiffman.
Main class code --
RainGame class code --
Drop class code --
Timer class code --
Catcher class code --
@GoToLoop thanks, but when I removed
extends PAppletfrom other three classes, they won't recognize
width,
height,
ellipse(). what shall I do about this?
Also, what do you mean by
PApplet callbacks? What exactly they are inside
RainGameclass?
@GoToLoop thanks, I went back to Processing in Eclipse with Multiple Classes and it says how and why need to remove
extends PApplet.
Now, I have corrected my code accordingly, this time there is no error, but I still could not get my canvas and the game. I am not sure where goes wrong.
In the output it says:
The corrected codes are below:
Main class --
RainGame --
Drop --
Timer --
Catcher --
P.S.: Strange that isn't listed in :-$
Me neither! B/c after copy & paste your code in Processing 3, each class in its own ".java" tab, it simply worked. Only small adjustment I had to do was paste MainToRun in the main ".pde" this way instead:
Everything else I didn't have to modify a single dot in order to play the game. <:-P
anyway, I work around this by working into two IDEs at the same time. Thanks everyone!
@quark and @GoToLoop, however, I still wonder as we repeatedly seen
args:
What could
argsor
passedArgsbe?
As they are
args[]or
passedArgs[], does it mean there can be multiple strings applied in args or passedArgs? Could you give some simple code examples?
Thanks!
From processing API -- we have seen
From the example code above -- we have seen
This is what I've said far way up:
Java's own main() parameter comes from either command line or shortcut arguments.
PApplet.main() in turn has extra features which I've already mentioned as well:
Correct order to fully merge Java's main() + PApplet.main()'s arguments is something like this:
But as I've said, args is almost always empty.
No1 calls Processing sketches from commandline passing args to it! 3:-O
BtW, in case args happen to be passed, and by using the model above, we can see those stored in variable args[] inside sketch: :-bd
But those are just advanced examples. As Processing PApplet.main()'s description says: :D
@GoToLoop
Saving a few key presses is not enough reason to go against good programming practice which recommends that identifiers should have meaningful names. I think it is important that we promote good programming practice on this forum, especially for newbies.
String className = Thread.currentThread().getStackTrace()[1].getClassName();
is so much clearer ;))
@blindfish
Glad you liked the quote
here is two more for you
I liked reading the quotes you posted. Although they were not on target here, but it doesn't take away their truth :)
As Processing programmers we're not used to call its API prefixed w/ anything.
Having to type in something simple like:
textFont(createFont("Arial", 12, true));as
parent.textFont(parent.createFont("Arial", 12, true));
is tedious & tiresome enough! I-)
Establishing some convention to represent the PApplet's reference as 1-character name won't diminish its clarity any more than using i & j as iterators, x & y & z as coordinates, w & h as dimensions: 8-X
p.textFont(p.createFont("Arial", 12, true));
That's just common sense folks! As even p5.js has adopted such convention as well: ;;)
Of course it isn't! But you were already using a much more verbose, slower and cryptic:
String className = RainGame.class.getName();for the sake of your IDE's rename/refactor features.
I've just gone a little farther and replaced it w/ a snippet not relying on any special IDE for it to work!
That is, no matter which class name that statement is in, it's gonna find that out on its own! \m/
r y c i t a t ;)
Thanks a million! @GoToLoop and @quark | https://forum.processing.org/two/discussion/comment/55316/ | CC-MAIN-2020-45 | refinedweb | 1,486 | 74.29 |
This tutorial will cover the use-case of having two or more Firebase environments and possibility of having each environment app installed to your phone. It is extremely useful when one wants to keep their
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development app.
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development app, you’ll be forced to uninstall your
production app.
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This will be first part of multi-part series, which will introduce ultimate CICD configuration for Flutter. I’ll split it to individual small tutorials as they standalone can contribute to many developers already.
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This is continuation from my previous article about flutter and material with cupertino widgets.
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import 'package:flutter/material.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { // This widget is the root of your application. @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', home: DoubleAppBarDemo(), ); } } class DoubleAppBarDemo…
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I build kick-ass mobile apps @ || Product Virtuoso and Startup Freak | https://aurimas-deimantas.medium.com/?source=post_internal_links---------3---------------------------- | CC-MAIN-2021-17 | refinedweb | 990 | 56.15 |
I should be working now, but fuck it, someone put an idea in my head about the Global Day of Coderetreat: Toronto[1], so I've been thinking, coding and doing some light research. Dann, if you're reading, this article is about 80% your fault.
The standard game of Life is played on a grid of squares. Each square may be alive or dead, and the rules of the game go like this.
When I initially talked at my wife[3] about this, I made the assumption that the way to model the problem is the obvious one. That is, define a grid, or an array of arrays, make some of them living, and then compute the next step according to the above rules. Because I had never actually written this program before, I reached for Common Lisp. I was going to try to be functional about it, and the first thing you need to do that is a function that takes a cell and finds its neighbors.
(defun neighbors (cell) (let ((l '(-1 0 1))) (destructuring-bind (x . y) cell (mapcan (lambda (dx) (loop for dy in l unless (and (zerop dx) (zerop dy)) collect (cons (+ x dx) (+ y dy)))) l))))
At this point I was still assuming that I'd be representing the board as a 2-dimensional array, so the output of this function was going to be used down the line to index into said array, returning a list of found live
cells. Except that as I was thinking about how best to do that[4] it occurred to me that it might be better to model the problem as a sparse array of living cells. If I were going for that approach, the output of
neighbors wouldn't be used for indexing at all; instead, using I could use it to get a count of how many neighbors each referred square has. That is,
CL-USER> (defparameter *blinker* '((1 . 0) (1 . 1) (1 . 2))) *BLINKER* CL-USER> (mapcan #'neighbors *blinker*) ((0 . -1) (0 . 0) (0 . 1) (1 . -1) (1 . 1) (2 . -1) (2 . 0) (2 . 1) (0 . 0) (0 . 1) (0 . 2) (1 . 0) (1 . 2) (2 . 0) (2 . 1) (2 . 2) (0 . 1) (0 . 2) (0 . 3) (1 . 1) (1 . 3) (2 . 1) (2 . 2) (2 . 3)) CL-USER>
That output tells me that, for example, the
cell
(2 . 2) currently has two living neighbors since it's mentioned twice in that list. Common Lisp doesn't have a built-in
group or similar, so I'm stuck
hashing things myself to collect those frequencies.
gethashtakes an optional third argument, which it returns as a default value. Meaning that if you're looking to use a
hash-tableto keep count of stuff you can express that as
(defun cells->cell-count-hash (cells) (let ((h (make-hash-table :test 'equal))) (loop for c in cells do (incf (gethash c h 0))) h))Sat, 22 Dec, 2012
(defun cells->cell-count-hash (cells) (let ((h (make-hash-table :test 'equal))) (loop for c in cells if (gethash c h) do (incf (gethash c h)) else do (setf (gethash c h) 1)) h))
You might think that you can bind a temporary variable to
(gethash c h) to get rid of that duplication. It won't do what you think it should. Feel free to try it and develop a theory of why. Anyhow, over to the REPL
CL-USER> (let ((h (cells->cell-count-hash (mapcan #'neighbors *blinker*)))) (loop for k being the hash-keys of h using (hash-value count) do (format t "~a : ~a~%" k count))) (0 . -1) : 1 (0 . 0) : 2 (0 . 1) : 3 (1 . -1) : 1 (1 . 1) : 2 (2 . -1) : 1 (2 . 0) : 2 (2 . 1) : 3 (0 . 2) : 2 (1 . 0) : 1 (1 . 2) : 1 (2 . 2) : 2 (0 . 3) : 1 (1 . 3) : 1 (2 . 3) : 1 NIL CL-USER>
That should illustrate it sufficiently for you. As an aside here, note that
hash-keys is not a function. It's actually a
loop keyword. And so is
hash-value. If you try to use either in plain ol' Common Lisp code, you'll get a plain ol'
unbound symbol error. This is the main reason I don't like to grub around hashes in CL; it's not very pleasant and involves a lot of plumbing built specifically for it.
maphash also exists[5], but counter-intuitively[6] always returns
NIL rather than a sequence, relying on side-effect to actually do things. That's ... less than satisfying.
Anyhow, moving on. We've got a pretty simplistic model of the world here, but it's enough to let me step through
life.
(defun life-step (cells) (let ((freqs (cells->cell-count-hash (mapcan #'neighbors cells)))) (loop for k being the hash-keys of freqs using (hash-value count) when (or (= 3 count) (and (= 2 count) (member k cells :test #'cell=))) collect k)))
I also defined
cell= just to help that
member call along[7].
(defun cell= (a b) (and (= (car a) (car b)) (= (cdr a) (cdr b))))
That conditional after the
when clause is a contraction of the Life rules, but the effect is the same. The single rule is, effectively
- If a cell has three neighbors, or has two neighbors and is alive, it's alive in the next step.
Because of the way we're representing the "board", that suffices. So this produced the expected output for the given
blinker input, and I didn't particularly feel the need to write a fancy grid-display for it, so I moved on to Haskell.
Same theory; simplified rules and represent the world as a sparse array of living cells; how would it look?
neighbors :: (Int, Int) -> [(Int, Int)] neighbors (x, y) = filter (/=(x,y)) . concat $ map xs l where l = [-1..1] xs dy = map (\dx -> (x + dx, y + dy)) lEDIT:
And then, I remembered list comprehensions, which turn
neighbors into a one-liner.
neighbors (x, y) = [(x+dx, y+dy) | dx <- [-1..1], dy <- [-1..1], (dx,dy) /= (0,0)]Thu, 06 Dec, 2012
Neighbors looks a bit different. As far as I know, there isn't a
loop analogue available in Haskell, so I'm "stuck" composing the functional primitives. It ends up saving me about four lines of code, and that's typically the case when I transform a destructive function into a functional one, so I want to make it clear that that wasn't a complaint. Before we move on, let me just spotlight something
(/=(x,y))
I pointed out a similar construct at a Toronto Lisp Group meeting a little while ago and didn't emphasize this enough. That bracketed expression is "the function of one argument that compares its argument to the tuple of
x and
y". Please note that this isn't a compiler macro, or similar trickery. Haskell curries[8] by default, and
/= is the inequality operator. So that tiny parenthesized expression is literally currying the tuple
(x, y) onto the right argument of the infix function
/=. You can generalize this to any other function.
Moving on.
lifeStep :: [(Int, Int)] -> [(Int, Int)] lifeStep cells = step cells where step = map head . filter viable . group . sort . concat . map neighbors viable [_,_,_] = True viable [c,_] = c `elem` cells viable _ = FalseEDIT:
List comprehensions strike again, but don't buy quite as much clarity this time.
lifeStep :: [(Int, Int)] -> [(Int, Int)] lifeStep cells = [head g | g <- grouped cells, viable g] where grouped = group . sort . concat . map neighbors viable [_,_,_] = True viable [c,_] = c `elem` cells viable _ = FalseThu, 06 Dec, 2012
You can see the simplified life rules again in the
viable local function. If there are 3 neighbors a cell is viable, if there are 2 neighbors and the cell is already a member of the living then it's viable, otherwise it's not.
where step = map head . filter viable . group . sort . concat . map neighbors
step is written entirely in point-free style, which might look odd to people coming from a background of purely mainstream languages. This might just be why newbs have a harder time with Haskell than we strictly seem we should. Once you understand it, it's obviously the most elegant and appropriate way of expressing a series of computations. Until you understand it, you can be forgiven for thinking that I'm just making shit up. Lets go through it step by
step. I mean, step.
First, we
map neighbors over the input, giving us a list of lists of cells. Then we
concatenate that, giving us a list of cells, then we
group . sort that, giving us a list of lists of cells again[9]. Finally, we
filter those lists for
viable cells and pull a single cell out of each list using
map head.
Note that, because Haskell is a lazy language, the actual program probably won't run in that sequence. Which is a good thing, because we'd otherwise be looking at 6 traversals of our input per
lifeStep, which is pretty
On^scary.
Oh, that was it, by the way.
import Data.List neighbors :: (Int, Int) -> [(Int, Int)] neighbors (x, y) = [(x+dx, y+dy) | dx <- [-1..1], dy <- [-1..1], (dx,dy) /= (0,0)] lifeStep :: [(Int, Int)] -> [(Int, Int)] lifeStep cells = [head g | g <- grouped cells, viable g] where grouped = group . sort . concat . map neighbors viable [_,_,_] = True viable [c,_] = c `elem` cells viable _ = False
I was amazed the first time I wrote it too; those 6-lines-plus-type-signatures-and-import of Haskell do exactly the same thing as my Common Lisp program from earlier. The term is elegance, I think, since I can still understand it, but it's possible to disagree on these points. The next step obvious step was writing the display functions and test output. Which promptly more than doubled the line-count.EDIT:
I could probably use list comprehensions here too, but I don't care enough about the display code to optimize it.Thu, 06 Dec, 2012 EDIT:
Ok, dammit, here
showWorld :: [(Int, Int)] -> IO () showWorld cells = mapM_ putStrLn $ map cellStr groupedByY where groupedByY = [[fst c | c <- cells, snd c == y] | y <- range] cellStr xs = [if c `elem` xs then '#' else ' ' | c <- range] range = worldRange cells worldRange cells = [least..greatest] where least = min x y greatest = max x' y' (x, y) = head cells (x', y') = last cellsThu, 06 Dec, 2012
showWorld :: [(Int, Int)] -> IO () showWorld cells = mapM_ putStrLn $ map cellStr $ map byY range where byY y = map fst $ filter (\c -> snd c == y) cells (x1, y1) = head cells (x1', y1') = last cells least = min x1 y1 greatest = max x1' y1' range = [least..greatest] cellStr xs = map (\c -> if c `elem` xs then '#' else ' ') range runLife :: Int -> [(Int, Int)] -> IO () runLife steps cells = rec (steps - 1) cells where rec 0 cells = showWorld cells rec s cells = do showWorld cells rec (s - 1) $ lifeStep cells main :: IO () main = do putStrLn "Glider >> 10" putStrLn "------------" runLife 10 [(1, 0), (2, 1), (0, 2), (1, 2), (2, 2)] putStrLn "" putStrLn "Blinker >> 3" putStrLn "------------" runLife 3 [(1, 0), (1, 1), (1, 2)]
I'm not going to go through this step-by-step; it does the not-very-interesting job of taking a sparse living cell array and outputting the minimum required grid to display it using sharps (for living cells) and spaces (for dead ones). It could probably be made more efficient, or it could be made more scalable by introducing grid limits rather than computing a needed grid size, but it's enough to show the principle.
inaimathi@lambda:~/langnostic/play/haskell$ ghc life.hs [1 of 1] Compiling Main ( life.hs, life.o ) Linking life ... inaimathi@lambda:~/langnostic/play/haskell$ ./life Glider >> 10 ------------ # # ### # # ## # # # ## # ## ## # # ### # # ## # # # ## # ## ## # # ### # # ## Blinker >> 3 ------------ # # # ### # # # inaimathi@lambda:~/langnostic/play/haskell$
At that point, I went on to write the Clojure version, but I won't be showing that. After a good three hours total, I had three programs written up in three languages, all using the same less-than-perfectly-obvious model of the world, and I kind of wanted to figure out whether I was barking up the right tree.
Life is on the Rosetta Code task list, so I took a look at the languages I'd covered. The Haskell version uses the grid approach with a multi-indexed
Array. I sort of understand what it's doing, even if the
life function has very obviously been written by a mathematician rather than a programmer, and it's not at all the same as what I'm doing.
The Common Lisp version does more or less the same thing, except without the emphasis on one-character variable/function names, so that it's pretty understandable if you're comfortable with Common Lisp. He's doing something similar to the Haskell mathematician though; defining a 2-dimensional array to hold the game board, then manipulating it[10] to produce the next generation of the world.
Page Down starts getting some mileage as I look through implementations in other languages, pointedly avoiding Prolog and Forth so that I'll have something interesting to explore with my pairing partner on Saturday. I'm beginning to get more and more worried as I read on; everything from D to TCL is using the grid representation, so I'm beginning to think that there's some obvious shortcoming to the sparse-array approach that I must have missed.
Before I go read up on what that is and how royally it bones performance or whatever, I turn to the Clojure implementation, reproduced here in full:
(defn neighbours [[x y]] (for [dx [-1 0 1] dy [-1 0 1] :when (not (and (zero? dx) (zero? dy)))] [(+ x dx) (+ y dy)])) (defn next-step [cells] (set (for [[cell n] (frequencies (mapcat neighbours cells)) :when (or (= n 3) (and (= n 2) (cells cell)))] cell)))
That's why I'm not showing the solution I worked up, by the way. I didn't even bother saving it after I read that. It was doing exactly the same thing, in algorithmic terms, but I'm a Clojure n00b. So I didn't know about
for[11], or
frequencies[12], and that made it quite a bit longer and thornier. This version doesn't pretty-print its grid, but shows the essence of the approach beautifully[13].
Looking through the rest of the languages[14], they all use the obvious grid model too. I actually haven't gone out to read up on the comparison of these two approaches[15] but having at least one crazy bastard other than me on the same train of thought at least tells me there might be something here. Or, this might be one of those places where the traditional representation has just become so well-known and obvious that everyone reaches for it outright even though it might not be the most elegant thing available.
Ok, that's my lunch hour up, I'm heading back to work. Hopefully I get some actual hacking done for the next installment and finally wrap up the authentication series. Though, to be fair, I guess it's more likely to be a write-up of my experience on Saturday.EDIT:
Addendum, because I hate myself. The Python version (minus display code). Woo.
from collections import defaultdict glider = [(1, 0), (2, 1), (0, 2), (1, 2), (2, 2)] blinker = [(1, 0), (1, 1), (1, 2)] def neighbors(cell): x,y = cell r = range(-1,2) return [(x+dx, y+dy) for dx in r for dy in r if not (dx, dy) == (0, 0)] def frequencies(cells): res = defaultdict(int) for cell in cells: res[cell] += 1 return res def lifeStep(cells): freqs = frequencies([n for c in cells for n in neighbors(c)]) return [k for k in freqs if freqs[k]==3 or (freqs[k]==2 and k in cells)]Thu, 06 Dec, 2012 EDIT:
Addendum the Second: All code from this article (plus printing code for each language) now available here.Sun, 09 Dec, 2012
Footnotes
1 - [back] - Registration is closed, but it's apparently fine to just show up if you're in the area.
2 - [back] - They actually reduce to between one and three simpler rules, depending on how you look at it, but we'll talk about that later.
3 - [back] - She always indulges me in these things, even though her own interest in the problem is minimal at best. I'm thankful for her patience on the multitude of days she's watched me talk to myself.
4 - [back] - I'll admit that I was, perhaps prematurely, also thinking about how I'd do it in Haskell, where indexing into a nonexistent cell is non-trivial and not very idiomatic in any case.
5 - [back] - And to be fair, the situation above could have been written more succinctly as
(maphash (lambda (k v) (format t "~a : ~a~%" k v)) (cells->cell-count-hash (mapcan #'neighbors *blinker*)))
6 - [back] - For a function with
map in its name.
7 - [back] - This is one of those places where better
destructuring-bind syntax would help to no end, by the way. If Clojure didn't have a polymorphic
=, neatly sidestepping the need for a
cell= at all, I could do
(defn cell= [a b] (let [[ax ay] a [bx by] b] (and (= ax bx) (= ay by))))
or just
(defn cell= [[ax ay] [bx by]] (and (= ax bx) (= ay by)))
In Common Lisp, using the destructuring version would actually take more code than just looking up
cars and
cdrs
8 - [back] - Har har, Simon. That's Hilarious.
9 - [back] - But organized by identity rather than by moore neighborhood center.
10 - [back] - Destructively, unlike in the Haskell version.
11 - [back] - Instead using
map/
reduce.
12 - [back] - Instead using the same tactic I used in Haskell, which is a pretty shitty thing to do in a language that isn't lazy by default.
13 - [back] - The earlier Haskell display code should be pretty easy to port anyhow, in case you really, really must see a grid of life squares printed as part of the solution.
14 - [back] - The ones before Clojure on that page.
15 - [back] - The article linked to from Rosetta Code isn't very informative.
Clojure solution has small bug: (cells cell) won't work. The easy fix is (some #{cell} cells).
I'd probably put this down to a lack of documentation.
It's not explicitly stated anywhere IN the code, but `next-step` assumes it's getting a set of cells as its input (not a list or array). For a generic sequence of cells, you're right, you'd need to check membership rather than just indexing into `cells`
Right, with sets it works fine.
In Haskell there wouldn't be such confusion :)
Haha.
Well, I wasn't going to say anything, but
`nextStep :: Set (Int, Int) -> Set (Int, Int)`
WOULD clear up this particular issue pretty effectively :) | http://langnostic.blogspot.com/2012/12/life-common-lisp-haskell-and-clojure.html | CC-MAIN-2017-39 | refinedweb | 3,174 | 67.89 |
Posted on 2007-08-20, last updated 2009-09-05 by Timo Bingmann at Permlink.
This code template can be used to integrate a Flex scanner and Bison parser pair into a modern C++ program. These two universal tools are very difficult to incorporate into a good C++ design. The template utilizes both Flex and Bison in C++ mode and their output are encapsulate into classes. Some tricky code is used to bind the two classes together. Thus the lexer and parser become fully re-entrant, as all state variables are contained in the class objects. Furthermore multiple different lexer-parser pairs can easily be linked into one binary, because they have different class names and/or are located in a different namespace.
Why use these old tools? Well, they are here to stay and they work well. But most important, the code generated by Flex and Bison requires no compile-time dependencies, because they generate fully autonomous source code. So far I have not found any modern parser generator which outputs independent code. It is even possible to compile the generated source on Windows with Visual C++ 2005.
The implemented grammar is a standard infix-notation calculator, which even supports some variables. This application is not the focus of the template, it is there as a starting-point for you to insert your own grammar.
See the README below for more information and pointers into the code.
For the changes between versions see the corresponding weblog entries for 0.1.3 and 0.1.4 or the ChangeLog below.
See bottom of this page for older downloads.
The parts of the example code written by myself are released into the public domain or, at your option, under the Do What The Fuck You Want To Public License (WTFPL). There are some special GPL license exceptions for the included source files from the Bison and Flex distributions. All in all you can just copy all the code and don't have to credit me at all.
The git repository containing all sources and packages is available by running
git clone
The current example package can be downloaded from
The following just mean you can copy the example code into your program or use it for whatever purpose without crediting me (though I would really like it if you did):
The parts of the example code written by myself are released into the public domain or, at your option, under the Do What The Fuck You Want To Public License (WTFPL), which can be found in the file COPYING. There are some special GPL license exceptions for the included source files from the Bison and Flex distributions.
The idea and method of this example is based on code from
Well, they are here to stay and they work well. These days there are much more sophisticated C++ parser generation frameworks around:
All these libraries do good jobs when you need to generate parsers for more difficult grammars.
However if you write a program with one of the frameworks above, then your users need that parser framework installed to compile your program. But Flex and Bison require no compile-time dependencies, because they generate fully autonomous source code. (And Flex and Bison are installed almost everywhere.) So far I have not found any modern parser generator which outputs independent code.
It is even possible to compile the generated source with Visual C++ on Windows (worked with 8.0 aka 2005). Flex and Bison need not be installed on the windows machine. The source package includes a VC++ solution and two project files.
The src directory contains the following source files. Note that some of them are automatically generated from others.
So if you wish to create a program using a C++ Flex lexer and Bison parser, you need to copy the following files:
The scanner, parser and driver classes are located within the example namespace. When coding a larger program, I believe it is most convenient to put all scanner/parser source files into a separate directory and build a static library. Then all parts of the parser are located in a separate namespace and directory.
This is a brief overview of the code's structure. Further detailed information is contained in the doxygen documentation, comments in the source and ultimately in the code itself.
The input stream is first converted by the lexical scanner into tokens. The scanner is defined by the list of regular expressions in scanner.ll . From this file Flex generates the file scanner.cc, which mainly contains a function called yylex(). This function returns the next token for the parser. For a C++ scanner the yylex() function is contained in a class, which is named yyFlexLexer by default. It is declared in the FlexLexer.h and is derived from the abstract FlexLexer class.
By defining the macro yyFlexLexer => ExampleFlexLexer in scanner.h, the default name of the scanner class is changed. Furthermore to extend yylex()'s parameter list, the class example::Scanner is derived from the ExampleFlexLexer class. It is mainly a forwarding class. By defining the macro YY_DECL, the yylex() function generated by Flex is renamed to example::Scanner::lex().
Another change to the default Flex code is that the token type is changed from
int to the enum example::Parser::token defined by parser.
Bison's support for C++ is much more sophisticated. In C++ mode it generates a class named example::Parser, which is located in parser.cc and declared in parser.h . The header file also defines the scanner tokens, which must be returned by the Flex scanner's regular expression rules. Bison's C++ skeleton also installs the three .hh files, which contain utility classes required by the parser.
In the example calculator the Bison code constructs a calculation node tree. The tree's nodes are derived from CalcNode and are evaluated to output the parsed expression's result.
The example::Driver class brings the two components scanner and parser classes together. It is the context parameter of the parser class. The hook between scanner object and parser object is done by defining the yylex() macro to be "driver.lexer->lex". This way the Bison parser requests the next token from the scanner object contained within the driver.
The example::Driver object can be accessed by the Bison actions. Therefore it will contain a reference to the data classes filled by the parser's rules. In the example it contains a reference to the CalcContext. Thus a refernce to a CalcContext must be given to the constructor of example::Driver. This CalcContext object will be filled with the parsed data.
To initiate parsing the example::Driver class contains the three functions example::Driver::parse_stream(), example::Driver::parse_file() and example::Driver::parse_string().
The example lexer and grammar is a simple floating point arithmetic calculator. It follows the usual operator precedence rules (sometimes called BODMAS or PEMDAS): Parentheses, Exponentation, Multiplication/Division, Addition/Subtraction.
Besides these simple arithmetic operators, the program also supports variables. These can be assigned a value and used in subsequent expressions.
It can be started interactively and will process expressions entered on the console. The expression's parse tree is printed and then evaluated. Here some examples:
The exprtest can also be used to process text files containing expressions. Within the file each line is parsed as an expression. Multiple expressions can be put into one line by terminating them with a semicolon '
;'. The exprtest outputs a parse tree for each parsed non-assignment line.
The above example file (included as
exprtest.txt) can be processed by calling
./exprtest exprtest.txt. The program outputs the following evaluation:
%uniondue to changed include file order.
yywrap()function in the FlexLexer class..
%uniondirective is used: in this case the include headers order is changed around by bison and breaks compilation. This was fixed by never including parser.h directly, but always using scanner.h.
yywrap()to the
yyFlexLexerclass. This function is automatically defined in any lexer source file generated by flex. However because I copied FlexLexer.h from an older flex distribution, the function definition throughs a "no member function" compiler error. | https://panthema.net/2007/flex-bison-cpp-example/ | CC-MAIN-2018-47 | refinedweb | 1,358 | 57.47 |
hi,
I have connected two databases with a reference field; Apartments and Clients. Basically each apartment will have one or more clients. So when i click the apartment name it will show all the clients related to it. I intend to fill the clients names using a form input. But i cannot connect the reference field; Apartment Name. is there any code to achieve this
okay i managed to make some progress with this code but i keep getting "Reference is broken".
import wixData from 'wix-data';
// ...
export function button10_click(event, $w) {
let toInsert = {
"apartmentName": $w("#input10").value,
"title": $w("#input9").value
};
wixData.insert("APARTMENT-CLIENT--NAME", toInsert)
.then( (results) => {
let item = results; //see item below
} )
.catch( (err) => {
let errorMsg = err;
} );
}
Hey there,
You need to put the _id of the apartment item in the apartment name field. The reference is really just storing the ID. The API documentation of this should be published shortly.
Hi, thank you for that
is there any code to retrieve the _id with a query when i input the Apartment Name with a user input?
thanks
You can query the collection of apartments for the one with the matching name and then use the _id (or the whole item will work as well) for your insert item.
$w.onReady(function () {
//TODO: write your page related code here...
});
import wixData from 'wix-data';
export function button10_click(event, $w) {
wixData.query('APARTMENT-NAME')
.eq('title', $w('#input10').value)
.find()
.then(res => {
let firstItem = res.items;
let toInsert = {
"apartmentName": firstItem,
"title": $w("#input9").value
};
wixData.insert("APARTMENT-CLIENT--NAME", toInsert)
.then((results) => {
let item = results;
})
.catch((err) => {
let errorMsg = err;
});
});
}
i have tried this code but it leaves the reference field blank when submitted
You might want to add some console.log() calls to debug your code.
Just by looking at it I can see that where you have:
where it should be:
it works perfect now.
thank you so much
Thanks for the coding here, though I still have an issue. My case is slightly different in that I'm trying to insert the input from a dropdown of the primary into the reference field of the more detailed database.
I had done it last week, I believe in using your code examples, and got it to work perfect, but the save feature seemed to be having issues, and it didn't save. Since then I've tried various things but thing worked until I got back here. But I still have an issue - using the code below works EXCEPT that the reference field value ends up on the next record of the dataset?
// item = results [0];
} )
.catch( (err) => {
let errorMsg = err;
} );
} );
}
one other things - why do I have to download any one of the images before the submit will work. | https://www.wix.com/corvid/forum/community-discussion/filling-a-reference-field-with-a-form-input | CC-MAIN-2020-10 | refinedweb | 465 | 73.78 |
Greeting,
Here is my code...
The question is that inStream has already been opened as a connection to an input file (data.dat) that contains the following data:
1 -2 3
4 -5 6
7 -8 9
and the the following declarations are in effect
int n1, n2, n3;
double r1, r2, r3;
char
c1, c2, c3,c4;
I should get the following answers according to the book:I should get the following answers according to the book:Code:#include <iostream> //cin,cout,<<,>> #include <fstream> //ifstream,ofstream #include <string> //string, getline() #include <cassert> //assert() using namespace std; int n1, n2, n3; double r1, r2, r3; char c1, c2, c3, c4; int main() { cout << "This program computes values assigned to each of the variables \n" << "in the input list and places its results in another file.\n\n"; // ------------------input section-------------------------------- cout << "Enter the name of the input file: "; string inputFileName; getline(cin, inputFileName); //get name of input file ifstream inStream; //open an input stream to the input file inStream.open(inputFileName.data()); //establish a connection assert(inStream.is_open()); //check for success inStream >> c1 >> n1 >> r1 >> r2 >> n2 >> c2 >> c3 >> r3; //read a value inStream.close(); //close the connection // ------------------------output section------------------------- while(getchar() != '\n'); cout << "Enter the name of the output file: "; string outputFileName; getline(cin, outputFileName); ofstream outStream(outputFileName.data()); //open an output stream to the output file // and establish a connection assert(outStream.is_open()); //check for success outStream << c1 << n1 << r1 << r2 << n2 << c2 << c3 << r3; //write a value outStream.close(); //close stream cout << "Processing complete.\n"; return 0; }
c1 = '1' n1 = 23, r1 = 45.6 r2 = error--real numbers cant contain letters(ie 'X')
My is 1-234-567-8, I am
Can anyone explain why the book cam up with these answers to the practice problems? | https://cboard.cprogramming.com/cplusplus-programming/27366-instream-practice-problem-not-working.html | CC-MAIN-2017-13 | refinedweb | 298 | 59.03 |
Introduction to the Python Pickle Module
Introduction
Pickling is a popular method of preserving food. According to Wikipedia, it is also a pretty ancient procedure – although the origins of pickling are unknown, the ancient Mesopotamians probably used the process 4400 years ago. By placing a product in a specific solution, it is possible to drastically increase its shelf life. In other words, it's a method that lets us store food for later consumption. If you're a Python developer, you might one day find yourself in need of a way to store your Python objects for later use. Well, what if I told you, you can pickle Python objects too?
Serialization
Serialization is a process of transforming objects or data structures into byte streams or strings. A byte stream is, well, a stream of bytes – one byte is composed of 8 bits of zeros and ones. These byte streams can then be stored or transferred easily. This allows the developers to save, for example, configuration data or user's progress, and then store it (on disk or in a database) or send it to another location. Python objects can also be serialized using a module called Pickle. One of the main differences between pickling Python objects and pickling vegetables is the inevitable and irreversible change of the pickled food's flavor and texture. Meanwhile, pickled Python objects can be easily unpickled back to their original form. This process, by the way, is universally known as deserialization. Pickling (or serialization in general) should not be confused with compression. The purpose of pickling is to translate data into a format that can be transferred from RAM to disk. Compression, on the other hand, is a process of encoding data using fewer bits (in order to save disk space). Serialization is especially useful in any software where it's important to be able to save some progress on disk, quit the program and then load the progress back after reopening the program. Video games might be the most intuitive example of serialization's usefulness, but there are many other programs where saving and loading a user's progress or data is crucial.
Pickle vs JSON
There is a chance that you have heard of JSON (JavaScript Object Notation), which is a popular format that also lets developers save and transmit objects encoded as strings. This method of serialization has some advantages over pickling. JSON format is human-readable, language-independent, and faster than pickle. It does have, however, some important limitations as well. Most importantly, by default, only a limited subset of Python built-in types can be represented by JSON. With Pickle, we can easily serialize a very large spectrum of Python types, and, importantly, custom classes. This means we don't need to create a custom schema (like we do for JSON) and write error-prone serializers and parsers. All of the heavy liftings is done for you with Pickle.
What can be Pickled and Unpickled
The following types can be serialized and deserialized using the Pickle module:
- All native datatypes supported by Python (booleans, None, integers, floats, complex numbers, strings, bytes, byte arrays)
- Dictionaries, sets, lists, and tuples - as long as they contain pickleable objects
- Functions and classes that are defined at the top level of a module
It is important to remember that pickling is not a language-independent serialization method, therefore your pickled data can only be unpickled using Python. Moreover, it's important to make sure that objects are pickled using the same version of Python that is going to be used to unpickle them. Mixing Python versions, in this case, can cause many problems. Additionally, functions are pickled by their name references, and not by their value. The resulting pickle does not contain information on the function's code or attributes. Therefore, you have to make sure that the environment where the function is unpickled is able to import the function. In other words, if we pickle a function and then unpickle it in an environment where it's either not defined or not imported, an exception will be raised. It is also very important to note that pickled objects can be used in malevolent ways. For instance, unpickling data from an untrusted source can result in the execution of a malicious piece of code.
Pickling a Python List
The following very simple example shows the basics of using the Pickle module in Python 3:
import pickle test_list = ['cucumber', 'pumpkin', 'carrot'] with open('test_pickle.pkl', 'wb') as pickle_out: pickle.dump(test_list, pickle_out)
First, we have to import the
pickle module, which is done in line 1. In line 3 we define a simple, three element list that will be pickled.
In line 5 we state that our output pickle file's name will be
test_pickle.pkl. By using the
wb option, we tell the program that we want to write (
w) binary data (
b) inside of it (because we want to create a byte stream). Note that the
pkl extension is not necessary – we're using it in this tutorial because that's the extension included in Python's documentation.
In line 6 we use the
pickle.dump() method to pickle our test list and store it inside the
test_pickle.pkl file.
I encourage you to try and open the generated pickle file in your text editor. You'll quickly notice that a byte stream is definitely not a human-readable format.
Unpickling a Python List
Now, let's unpickle the contents of the test pickle file and bring our object back to its original form.
import pickle with open('test_pickle.pkl', 'rb') as pickle_in: unpickled_list = pickle.load(pickle_in) print(unpickled_list)
As you can see, this procedure is not more complicated than when we pickled the object. In line 3 we open our
test_pickle.pkl file again, but this time our goal is to read (
r) the binary data (
b) stored within it.
Next, in line 5, we use the
pickle.load() method to unpickle our list and store it in the
unpickled_list variable.
You can then print the contents of the list to see for yourself that it is identical to the list we pickled in the previous example. Here is the output from running the code above:
$ python unpickle.py ['cucumber', 'pumpkin', 'carrot']
Pickling and Unpickling Custom Objects
As I mentioned before, using Pickle, you can serialize your own custom objects. Take a look at the following example:
import pickle class Veggy(): def __init__(self): self.color = '' def set_color(self, color): self.color = color cucumber = Veggy() cucumber.set_color('green') with open('test_pickle.pkl', 'wb') as pickle_out: pickle.dump(cucumber, pickle_out) with open('test_pickle.pkl', 'rb') as pickle_in: unpickled_cucumber = pickle.load(pickle_in) print(unpickled_cucumber.color)
As you can see, this example is almost as simple as the previous one. Between the lines 3 and 7 we define a simple class that contains one attribute and one method that changes this attribute. In line 9 we create an instance of that class and store it in the
cucumber variable, and in line 10 we set its attribute
color to "green".
Then, using the exact same functions as in the previous example, we pickle and unpickle our freshly created
cucumber object. Running the code above results in the following output:
$ python unpickle_custom.py green
Remember, that we can only unpickle the object in an environment where the class
Veggy is either defined or imported. If we create a new script and try to unpickle the object without importing the
Veggy class, we'll get an "AttributeError". For example, execute the following script:
import pickle with open('test_pickle.pkl', 'rb') as pickle_in: unpickled_cucumber = pickle.load(pickle_in) print(unpickled_cucumber.color)
In the output of the script above, you will see the following error:
$ python unpickle_simple.py Traceback (most recent call last): File "<pyshell#40>", line 2, in <module> unpickled_cucumber = pickle.load(pickle_in) AttributeError: Can't get attribute 'Veggy' on <module '__main__' (built-in)>
Conclusion
As you can see, thanks to the Pickle module, serialization of Python objects is pretty simple. In our examples, we pickled a simple Python list – but you can use the exact same method to save a large spectrum of Python data types, as long as you make sure your objects contain only other pickleable objects. Pickling has some disadvantages, the biggest of which might be the fact that you can only unpickle your data using Python – if you need a cross-language solution, JSON is definitely a better option. And finally, remember that pickles can be used to carry the code that you don't necessarily want to execute. Similarly to pickled food, as long as you get your pickles from trusted sources, you should be fine.Reference: stackabuse.com | https://www.codevelop.art/introduction-to-the-python-pickle-module.html | CC-MAIN-2022-40 | refinedweb | 1,456 | 54.12 |
IRC log of xproc on 2009-08-06
Timestamps are in UTC.
14:59:12 [RRSAgent]
RRSAgent has joined #xproc
14:59:12 [RRSAgent]
logging to
14:59:29 [Norm]
Meeting: XML Processing Model WG
14:59:29 [Norm]
Date: 6 Aug 2009
14:59:29 [Norm]
Agenda:
14:59:29 [Norm]
Meeting: 151
14:59:29 [Norm]
Chair: Norm
14:59:30 [Norm]
Scribe: Norm
14:59:32 [Norm]
ScribeNick: Norm
15:00:42 [ht]
ht has joined #xproc
15:00:49 [ht]
oops, how time do fly
15:00:54 [ht]
running to grab T, brb
15:01:15 [PGrosso]
PGrosso has joined #xproc
15:01:26 [Norm]
ok
15:02:13 [Norm]
Zakim, this is xproc
15:02:13 [Zakim]
ok, Norm; that matches XML_PMWG()11:00AM
15:05:11 [alexmilowski]
alexmilowski has joined #xproc
15:05:20 [Norm]
Zakim, who's on the phone?
15:05:20 [Zakim]
On the phone I see Norm, PGrosso, Vojtech
15:06:29 [Zakim]
+Alex_Milows
15:07:28 [ht]
zakim, please call ht-781
15:07:29 [Zakim]
ok, ht; the call is being made
15:07:31 [Zakim]
+Ht
15:08:38 [Norm]
Present: Norm, Paul, Vojtech, Henry, Alex
15:08:45 [Norm]
Topic: Accept this agenda?
15:08:45 [Norm]
->
15:08:53 [Norm]
Accepted.
15:08:58 [Norm]
Topic: Accept minutes from the previous meeting?
15:08:58 [Norm]
->
15:09:04 [Norm]
Accepted.
15:09:10 [Norm]
Topic: Next meeting: telcon 20 Aug 2009
15:09:30 [Norm]
Cancelling 13 Aug for Balisage
15:09:56 [Norm]
Henry gives regrets for 20 Aug, 27 Aug
15:10:35 [Norm]
Topic: 155 Circular and re-entrant libraries
15:11:01 [Norm]
Basically, what we've got doesn't work. Henry has made an alternate proposal.
15:11:17 [Norm]
->
15:12:05 [Norm]
Vojtech: I think there's still an issue with nested pipelines.
15:12:27 [Norm]
Henry: I think there is a problem...but not with nested pipelines.
15:12:52 [Norm]
...I don't think nested pipelines are a problem because the algorithm stops when it hits a p:pipeline child.
15:13:55 [Norm]
Henry: Consider a pipeline that has an import and a nested pipeline (as a sibling of import)
15:14:20 [Norm]
...And that nested pipeline defines symbols (nested pipelines or an import of its own).
15:15:39 [ht]
[pipe <import a> [pipe <import b>][pipe <import c>]]
15:16:45 [Norm]
Scribe struggles
15:17:00 [Norm]
Henry: The problem is that the algorithm as I specified it doesn't check the nested pipelines.
15:18:14 [Norm]
...I think I know how to fix that without changing the algorithm, but we need a different set of initial conditions.
15:19:13 [Norm]
Henry: To check a pipeline, you need to know the exports of its parent and the URIs that were involved in checking that and you start with those.
15:19:48 [Norm]
Henry: I'll send another message in a little while with an update.
15:22:47 [Norm]
Vojtech: I'm happier with the new proposal, including Henry's addendum. I think it's easier to understand.
15:22:52 [Norm]
Norm: Yes, I think so to.
15:23:30 [Norm]
Norm: Ok, we'll continue the review in email and touch base again at the next telcon.
15:24:00 [Norm]
Topic: 148 Parameter names cannot be in the XProc namespace
15:24:24 [Norm]
Vojtech: For options and variables, the spec says they can't be in the XProc namespace. It says the same thing about paramters.
15:24:38 [Norm]
...But I don't think it can be a *static* error for parameters.
15:25:05 [Norm]
Norm: Right. It's clearly not a static error.
15:25:17 [Norm]
Vojtech: Is it really necessary to say this about parameters?
15:26:25 [Norm]
Norm: We own it, that's why we say it, but I don't feel strongly about it.
15:27:56 [Norm]
Norm: Would anyone ever need to write a stylesheet that used parameters in the XProc namespace?
15:28:12 [Norm]
...I can't think of a reason. I'm inclined to leave the prohibition but make the parameter case dynamic.
15:28:18 [Norm]
Vojtech: But leave options and variables static?
15:28:20 [Norm]
Norm: Yes.
15:28:36 [Norm]
Propsal: Keept he prohibition, create a new dynamic error for the parameters case.
15:28:49 [Norm]
Accepted.
15:28:55 [Norm]
s/Keept he/Keep the/
15:29:31 [Norm]
Topic: 149 UUID
15:29:36 [Norm]
Norm: I think this is editorial.
15:29:48 [Norm]
Alex: I can dig up a normative reference and send it to you.
15:29:53 [Norm]
Norm: Thanks!
15:30:06 [Norm]
ACTION: Alex to find a normative reference for UUID algorithms.
15:30:29 [Norm]
Topic: 150 err:XD0002 and err:XD0011 and err:XD0029
15:33:00 [Norm]
Norm: Yes, it seems odd to have all three. We could lose 2 or 11 and 29 I think.
15:33:44 [Norm]
Norm: I guess losing 2 is the way to go, it's in a part of the spec distant from the other constraints on p:document and p:data.
15:34:44 [Norm]
Vojtech: I would remove 2.
15:35:02 [Norm]
Proposal: Remove err:XD0002 in favor of the two more specific errors, 11 and 29.
15:35:13 [Norm]
Accepted.
15:35:35 [alexmilowski]
Odd: Here's the official spec for UUIDs:
15:35:40 [Norm]
Topic: 151: Why is err:XC0001 a step error?
15:37:44 [Norm]
Vojtech explains why they should both be dynamic errors.
15:37:48 [Norm]
Norm: I think you're right.
15:38:08 [Norm]
Proposal: Rename err:XC0001 to some appropriate dynamic error number
15:39:42 [Norm]
Norm: Actually, I think err:XC0001 is simply subsumed by err:XD0020. There's no need to call out method if we aren't going to call out all of them.
15:40:50 [Norm]
Vojtech: Do we need two: one for invalid values and one for unsupported values?
15:41:06 [Norm]
Norm: I don't know, I'm not sure users will get value out of that distinction.
15:42:10 [Norm]
Vojtech: When I was writing the serialization tests, I had problems telling them apart.
15:42:19 [Norm]
Norm: Sold!
15:42:41 [Norm]
Proposal: Remove err:XC0001 using err:XD0020 there instead.
15:42:51 [Norm]
Accepted.
15:43:04 [Norm]
Topic: 152: p:http-request and err:XC0020
15:44:47 [Norm]
Alex: In both cases, it's about making sure the values are consistent.
15:45:52 [Norm]
Norm: Does anyone diagree that those are two cases of the same error, that is that one error code is sufficient.
15:46:45 [Norm]
Vojtech: The first definition talks specifically about the header value.
15:47:11 [Norm]
Alex: The spirit of this error is that to make a request, you have to get all the packaging right: headers, options, etc. have to match.
15:47:34 [Norm]
...The first mention talks about headers, but the boundry and a few other things also come into play.
15:48:07 [Norm]
Norm: I'm happy to reword err:XC0020 so that it's clear that what we're testing is general consistency in a request.
15:48:49 [Norm]
Proposal: Generalize err:XC0020 so that it's more appropriate for both cases.
15:49:03 [Norm]
Accepted.
15:49:15 [Norm]
ACTION: Norm to generalize err:XC0020 appropriately.
15:49:57 [Norm]
Topic: 156: What nodes does replace act on?
15:50:17 [Norm]
Vojtech: The replace step talks about the "elements" that it matches, but later on it talks about comments, PIs, text, etc.
15:50:22 [Norm]
...I think it should talk about nodes instead of elements.
15:50:25 [Norm]
Norm: Sounds right to me.
15:50:59 [Norm]
Proposal: Replace elements with nodes where appropropriate to make the description accurately reflect what the step does.
15:51:42 [Norm]
Accepted.
15:51:55 [Norm]
Topic: Any other business?
15:52:49 [Norm]
Norm: We're getting very close to being done. Maybe September? I'll have a more coherent report of coverage by the next meeting.
15:52:56 [Norm]
No other business heard.
15:53:37 [Norm]
Alex: Who's going to Balisage?
15:53:43 [Norm]
Norm: I think it's you and I and Mohamed.
15:53:58 [Norm]
Adjourned.
15:54:01 [Zakim]
-Ht
15:54:02 [Zakim]
-Alex_Milows
15:54:02 [Zakim]
-Norm
15:54:02 [Zakim]
-Vojtech
15:54:03 [Zakim]
XML_PMWG()11:00AM has ended
15:54:04 [Zakim]
Attendees were Norm, Vojtech, PGrosso, Alex_Milows, Ht
15:54:10 [Norm]
RRSAgent, set logs world visible
15:54:14 [Norm]
RRSAgent, draft minutes
15:54:14 [RRSAgent]
I have made the request to generate
Norm
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ht has left #xproc | http://www.w3.org/2009/08/06-xproc-irc | CC-MAIN-2014-41 | refinedweb | 1,546 | 72.87 |
- 3 tier x 4 tier, using an ORM
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- <xsl:when syntax question pertaining to an OR statement | https://bytes.com/sitemap/f-312-p-75.html | CC-MAIN-2019-43 | refinedweb | 3,368 | 54.93 |
Alright, I was thinking maybe to reverse the loop conditions.
I was thinking to make j = the length of the string aka 7 in this case, and make sure its greater than 0, and decrement j each time through the loop.
That way I could add the 7th character, then the 6th character, etc until it reached the end of the string.
EDIT: OH, yes, by making j = the entire length of the word itself, it is a value that is 1 greater than the entire length, so I changed the condition to be the j = the length of the word itself - 1 (in actual programming language of course)
Why is it not adding the 'T' in Timothy though?
Hmm, probably has to do with the < 0 condition in the for loop.
EDIT # 2: I changed the loop condition to be >= 0, and it DID add the final 'T', now to add more words to see if this can work on any set of names.
Here's my code:
Code:import java.sql.Date; import org.omg.CORBA.PUBLIC_MEMBER; public class Chapt4_Exercise5 { public static void main (String[] args) { /* 5. Write a program that reverses the sequence of letters in each * word of your chosen paragraph from Exercise 3. * * For instance, "To be or not to be." becomes "oT eb ro ton ot eb." */ // Old Paragraph String: // String paragraph = "Far best is he who knows all things himself. Good, he that hearkens when men counsel right. But he who neither knows, nor lays to heart. Another's wisdom, is a useless wight."; String paragraph = "Timothy"; //); } // REVERSE SECTION: System.out.println("NOW ENTERING REVERSE SECTION: "); // Make a String array that will hold the reverse forms of the // elements found in the subStr[] array: String[] reverse_array = new String[count]; // Using A Tokenizer is on p. 149: String [] parts_of_paragraph = paragraph.split("[ ]", count); // Create a StringBuilder for later use: StringBuilder reverse_string = new StringBuilder(); // Print out the parts of the parts_of_paragraph array for debugging: for(int i = 0; i < parts_of_paragraph.length; i++) { // Print out element being examined: System.out.println("Current element: " + parts_of_paragraph[i]); // Reverse code goes in here: /* Notes from NormR * Given "ABC" * loop * get next letter: "A", "B", "C" * add letter to start of output string: "A", "BA", "CBA" * end loop * The end comments separated by commas are the result each loop * */ // First step: Loop to look at each individual letter: for(int j = ((parts_of_paragraph[i].length())-1); j >= 0; j--) { // Output character to be sure you're now in a deeper // level: System.out.println("Current char of " + parts_of_paragraph[i] + ": " + parts_of_paragraph[i].charAt(j)); // Confused if I should use .append or .insert, and // whether or not to add a CharSeq as well: reverse_string.append(parts_of_paragraph[i].charAt(j)); System.out.println("Here are the contents of the reverse_string StringBuilder: " + reverse_string); } } } }Code:Timothy NOW ENTERING REVERSE SECTION: Current element: Timothy Current char of Timothy: y Here are the contents of the reverse_string StringBuilder: y Current char of Timothy: h Here are the contents of the reverse_string StringBuilder: yh Current char of Timothy: t Here are the contents of the reverse_string StringBuilder: yht Current char of Timothy: o Here are the contents of the reverse_string StringBuilder: yhto Current char of Timothy: m Here are the contents of the reverse_string StringBuilder: yhtom Current char of Timothy: i Here are the contents of the reverse_string StringBuilder: yhtomi Current char of Timothy: T Here are the contents of the reverse_string StringBuilder: yhtomiT | http://forums.devshed.com/java-help-9/errors-reversing-characters-substring-array-953873-4.html | CC-MAIN-2014-35 | refinedweb | 574 | 59.84 |
3.17. Predicting House Prices on Kaggle¶
The previous chapters introduced a number of basic tools to build deep networks and to perform capacity control using dimensionality, weight decay and dropout. It’s time to put our knowledge to good use by participating in a Kaggle competition. Predicting house prices is the perfect start, since its data is fairly generic and doesn’t have much regular structure in the way text of images do. Note that the dataset is not the Boston housing dataset of Harrison and Rubinfeld, 1978. Instead, it consists of the larger and more fully-featured dataset of house prices in Ames, IA covering 2006-2010. It was collected by Bart de Cock in 2011. Due to its larger size it presents a slightly more interesting estimation problem.
In this chapter we will apply what we’ve learned so far. In particular, we will walk you through details of data preprocessing, model design, hyperparameter selection and tuning. We hope that through a hands-on approach you will be able to observe the effects of capacity control, feature extraction, etc. in practice. Such experience is vital if you want to become an experienced data scientist.
3.17.1. Kaggle¶
Kaggle is a popular platform for machine learning competitions. It combines data, code and users in a way to allow for both collaboration and competition. For instance, you can see the code that (some) competitors submitted and you can see how well you’re doing relative to everyone else. If you want to participate in one of the competitions, you need to register for an account. So it’s best to do this now.
Fig. 3.11 Kaggle website
On the House Prices Prediction page you can find the data set (under the data tab), submit predictions, see your ranking, etc.; You can find it at the URL below:
Fig. 3.12 House Price Prediction
3.17.2. Accessing and Reading Data Sets¶
The competition data is separated into training and test sets. Each record includes the property values of the house and attributes such as street type, year of construction, roof type, basement condition. The data includes multiple datatypes, including integers (year of construction), discrete labels (roof type), floating point numbers, etc.; Some data is missing and is thus labeled ‘na’. The price of each house, namely the label, is only included in the training data set (it’s a competition after all). The ‘Data’ tab on the competition tab has links to download the data.
We will read and process the data using
pandas, an efficient data
analysis toolkit. Make
sure you have
pandas installed for the experiments in this section.
In [1]:
# If pandas is not installed, please uncomment the following line: # !pip install pandas %matplotlib inline import gluonbook as g.
In .
In [3]:
print(train_data.shape) print(test_data.shape)
(1460, 81) (1459, 80)
Let’s take a look at the first 4 and last 2 features as well as the label (SalePrice) from the first 4 examples:
In [4]:
train_data.iloc[0:4, [0, 1, 2, 3, -3, -2, -1]]
Out[4]:
We can see that in each example, the first feature is the ID. This helps the model identify each training example. While this is convenient, it doesn’t carry any information for prediction purposes. Hence we remove it from the dataset before feeding the data into the network.
In [5]:
all_features = pd.concat((train_data.iloc[:, 1:-1], test_data.iloc[:, 1:]))
3.17. Hence it makes sense to treat them equally.
In [6]:
numeric_features = all_features.dtypes[all_features.dtypes != 'object'].index all_features[numeric_features] = all_features[numeric_features].apply( lambda x: (x - x.mean()) / (x.std())) # after standardizing the data all means vanish, hence we can set missing values to 0 all_features = all.
In [7]:
# Dummy_na=True refers to a missing value being a legal eigenvalue, and creates an indicative feature for it. all_features = pd.get_dummies(all_features, dummy_na=True) all_features.shape
Out[7]:
(2919, 354)
You can see that this conversion increases the number of features from
79 to 331. Finally, via the
values attribute we can extract the
NumPy format from the Pandas dataframe and convert it into MXNet’s
native representation - NDArray for training.
In [8]:
n_train = train_data.shape[0] train_features = nd.array(all_features[:n_train].values) test_features = nd.array(all_features[n_train:].values) train_labels = nd.array(train_data.SalePrice.values).reshape((-1, 1))
3.17.4. Training¶
To get started we train a linear model with squared loss. This will obviously not lead to a competition winning submission but it provides a sanity check to see whether there’s meaningful information in the data. It also amounts to a minimum baseline of how well we should expect any ‘fancy’ model to work.
In [9]:
loss = gloss.L2Loss() def get_net(): net = nn.Sequential() net.add(nn.Dense(1)) net.initialize() return net
House prices, like shares, are relative. That is, we probably care more about the relative error \(\frac{y - \hat{y}}{y}\) than about the absolute error. For instance, getting a house price wrong by USD 100,000 is terrible in Rural Ohio, where the value of the house is USD 125,000. On the other hand, if we err by this amount in Los Altos Hills, California, we can be proud of the accuracy of our model (the median house price there exceeds 4 million).
One way to address this problem is to measure the discrepancy in the logarithm of the price estimates. In fact, this is also the error that is being used to measure the quality in this competition. After all, a small value \(\delta\) of \(\log y - \log \hat{y}\) translates into \(e^{-\delta} \leq \frac{\hat{y}}{y} \leq e^\delta\). This leads to the following loss function:
In [10]: the previous sections, the following training functions use the Adam optimization algorithm. Compared to the previously used mini-batch stochastic gradient descent, the Adam optimization algorithm is relatively less sensitive to learning rates. This will be covered in further detail later on when we discuss the details on Optimization Algorithms in a separate chapter.
In [11]:
3.17.5. k-Fold Cross-Validation¶
The k-fold cross-validation was introduced in the section where we discussed how to deal with “Model Selection, Underfitting and Overfitting”. - this is not the most efficient way of handling data and we would use something much smarter if the amount of data was considerably larger. But this would obscure the function of the code considerably and we thus omit it.
In [12]:.
In [13]:: gb.semilogy(range(1, num_epochs + 1), train_ls, 'epochs', 'rmse', range(1, num_epochs + 1), valid_ls, ['train', 'valid']) print('fold %d, train rmse: %f, valid rmse: %f' % ( i, train_ls[-1], valid_ls[-1])) return train_l_sum / k, valid_l_sum / k
3.17.6. Model Selection¶
We pick a rather un-tuned set of hyperparameters and leave it up to the reader to improve the model considerably. Finding a good choice can take quite some time, depending on how many things one wants to optimize over. Within reason the k-fold crossvalidation approach is resilient against multiple testing. However, if we were to try out an unreasonably large number of options it might fail since we might just get lucky on the validation split with a particular set of hyperparameters.
In [14]:.169774, valid rmse: 0.156914 fold 1, train rmse: 0.162122, valid rmse: 0.188965 fold 2, train rmse: 0.163616, valid rmse: 0.167943 fold 3, train rmse: 0.167810, valid rmse: 0.154595 fold 4, train rmse: 0.162585, valid rmse: 0.182780 5-fold validation: avg train rmse: 0.165182, avg valid rmse: 0.170239
You will notice that sometimes the number of training errors for a set of hyper-parameters can be very low, while the number of errors for the \(K\)-fold cross validation may be higher. This is most likely a consequence of overfitting. Therefore, when we reduce the amount of training errors, we need to check whether the amount of errors in the k-fold cross-validation have also been reduced accordingly.
3.17.
In [15]:
def train_and_pred(train_features, test_feature, train_labels, test_data, num_epochs, lr, weight_decay, batch_size): net = get_net() train_ls, _ = train(net, train_features, train_labels, None, None, num_epochs, lr, weight_decay, batch_size) gb.semilogy(range(1, num_epochs + 1), train_ls, 'epochs', 'rmse') the model. A good sanity check is to see whether the predictions on the test set resemble those of the k-fold crossvalication process. If they do, it’s time to upload them to Kaggle.
In [16]:
train_and_pred(train_features, test_features, train_labels, test_data, num_epochs, lr, weight_decay, batch_size)
train rmse 0.162878
A file,
submission.csv will be generated by the code above (CSV is
one of the file formats accepted by Kaggle). Next, we can submit our
predictions on Kaggle and compare them to the actual house price (label)
on the testing data set, checking for errors. The steps are quite
simple:
- Log in to the Kaggle website and visit the House Price Prediction Competition page.
- Click the “Submit Predictions” or “Late Submission” button on the right.
- Click the “Upload Submission File” button in the dashed box at the bottom of the page and select the prediction file you wish to upload.
- Click the “Make Submission” button at the bottom of the page to view your results.
Fig. 3.13 Submitting data to Kaggle
3.17.
3.17.9. Problems? | http://gluon.ai/chapter_deep-learning-basics/kaggle-house-price.html | CC-MAIN-2019-04 | refinedweb | 1,557 | 66.03 |
#include <Servo.h> Servo yservo; // create servo object to control a servo Servo zservo; void setup() { Serial.begin(9600); yservo.attach(9); // attaches the servo on pin 9 to the servo object \ zservo.attach(10);} void loop() { Serial.write("Start y-------"); yservo.write(0); delay(500); yservo.write(180); delay(1000); Serial.write("Start z-------"); zservo.write(0); delay(500); zservo.write(180); delay(1000);}
Hi,Looks fine, check your wiring and check that you have a common ground connection between the two power sourcesDuane B
In fact the non working servo doesn't even hold, its like theirs no signal going to it at all.
I have tried this on both a duemilanove and a mega 2560
Quote from: CaptRR on Aug 12, 2012, 10:46 pm In fact the non working servo doesn't even hold, its like theirs no signal going to it at all.Then maybe that servo isn't getting power?. It will hold without a signal I think. Anyway either its a wiring problem or you've burnt-out pin 10. Easy to test either hypothesis with multimeter.
OK, so you have tested with pin 9 and 10. What abouth the other 10 output pins? | http://forum.arduino.cc/index.php?topic=118245.msg897219 | CC-MAIN-2017-26 | refinedweb | 201 | 69.18 |
this keyword
1.this represents an object, which can appear in instance methods and construction methods, but not in class methods;
2. Use this in the construction method. This represents the object created by the construction method
3. Use this in the instance method, which represents the current object calling the method
encapsulation
- Encapsulation can be considered as a protective barrier to prevent the code and data of this class from being randomly accessed by the code defined by the external class. The main function of encapsulation is that we can modify our implementation code without modifying the program fragments that call our code.
Steps to implement Java encapsulation
1. Attribute privatization;
Modify the attribute with private. If the attribute is set to private, it can only be accessed by this class, and can not be accessed by other classes
2. Provide getter and setter methods externally as the entry to access private properties
Any class that wants to access private member variables in the class must pass through these getter and setter methods.
- get method: used to read data
public return value type get + initial capital of attribute name (no parameter){
return xxx;
}
- set method: used to modify data
Public void set + initial capitalization of attribute name (with one parameter){
xxx = parameter;
}
public class EncapTest{ //1. Property privatization private String name; private String idNum; private int age; //Provide getter and setter methods externally; } }
When accessing:()); } } //The operation results are as follows: Name : James Age : 20
Summary:
- this is a reference that holds the memory address to itself
- this. Most of them can be omitted, but they cannot be omitted when the real column variable and the global variable have the same name;
- this() syntax can only appear in the first line of the constructor, indicating that the current constructor calls other constructors of this class for code reuse;
- One copy of an object is an instance variable, and one copy of all objects is a static variable;
Code column:
package day1; /*Title: * Define a date class that can represent year, month and day * If the parameterless construction method is called, the default creation date is January 1, 1970 * You can also call a constructor with parameters to create a date object * In the future, develop the habit of code encapsulation * */ class Date{//Encapsulation: privatize the attributes first, and provide get and set methods externally private int year; private int month; private int day; //1. Nonparametric construction method public Date() { this.year=1997; this.month=1; this.day=1; } //2. Parametric construction method public Date(int year, int month, int day) { super(); this.year = year; this.month = month; this.day = day; } //3.set and get public int getYear() { return year; } public void setYear(int year) { this.year = year; } public int getMonth() { return month; } public void setMonth(int month) { this.month = month; } public int getDay() { return day; } public void setDay(int day) { this.day = day; } //Provides a way to print dates public void dayin(){ System.out.println(year+"year"+month+"month"+day+"day"); } } //Main function, i.e. entry public class Book{ public static void main(String[] args) { //Call parameterless constructor Date a1=new Date(); a1.dayin(); //Call the constructor with parameters Date a2=new Date(2021,10,5); a2.dayin(); } }
Contents contained in the class body currently studied:
1. Instance variables and methods
2. Static variables and static methods
3. Construction method
4. Method{
Local variables;
}
4. Static code block
5. Example code block
The general order of writing code at present:
- Classes and main methods of eclips
- Customize a class, which includes: first write the attribute (customize each instance or static variable), the construction method includes writing both without parameters and with parameters, encapsulation (first private each attribute, then provide set and get methods externally, and provide access entry), and then customize the instance or static method;
- Create an object in the main class (or main method)
- Object calls instance methods or variables; class name calls static methods or variables
code:
package review; public class review2 { //Static code block static{ System.out.println("stay review2 Execute when class is loaded"); }//Although this program has two static code blocks, execute this first because the main method in this class is executed first, and the main method loads the review2 class first //Class loading is like this: before program execution, all classes that need to be loaded are loaded into the JVM. After loading, the main method will be executed public static void main(String[] args) { //Call parameterless construction method when creating object Student s=new Student(); s.m2(); Student.m1(); } } //Student class class Student{ static String job="study";//Static variable private String name; private int no;//Student number //Construction method, no participation and participation public Student() { //Assuming that the construction method without parameters is called, the default student ID is 216 and the name is Zhang San; this("Zhang San",216);//Use this() } public Student(String name, int no) { super(); this.name = name; this.no = no; } //Encapsulation, set and get methods public String getName() { return name; } public void setName(String name) { this.name = name; } public int getNo() { return no; } public void setNo(int no) { this.no = no; } //Static code block static { System.out.println("stay Student Execute when class is loaded"); } //Instance code block { System.out.println("The construction method is executed once, and it is executed once here"); } //Example method public void m2() { System.out.println(name+"just"+job); //Equivalent to below /*name Although it is privatized, it can be accessed in this class, * In other classes, you can only access the encapsulated properties in this class through set and get*/ System.out.println(this.name+"just"+Student.job); } //Static method public static void m1() { Student a=new Student(); System.out.println(a.name+"Have a meal"); System.out.println(a.name+job); } } | https://programmer.group/encapsulation-of-this-keyword-and-code.html | CC-MAIN-2021-49 | refinedweb | 963 | 51.18 |
How do you keep a fork up to date with the main repository on GitHub?
It seems like quite a few people have asked me this over the last few months.
I'm not sure how many patterns there are for accomplishing this in git (I'd guess quite a few), but I have one that I use pretty much exclusively.
Let's identify why this is necessary, first. If you find an Open Source repository that you'd like to contribute to or keep a copy of, it's a common practice to
fork that repository.
Forking a repository just means making a copy of it, presumably so that you can make changes to it without affecting the original repository. In many cases, that's because you don't have write access to the original repository.
On GitHub (where the term fork is commonly used) all you have to do is click the big fork button at the top of a repository. After a few seconds, you'll have your own copy of the original repository stored under your namespace.
If you intend to make changes to your fork, you'll most likely want to clone it to your local environment. For this article, I'll use my fork of the Solidus.io project (a project I help maintain on GitHub).
My fork is located at github.com/jacobherrington/solidus. To clone it to my local machine, I could run this git command:
git clone git@github.com:jacobherrington/solidus.git
Let's say I create this fork, clone it, then leave it alone for six months.
In six months, the original repository has changed substantially, and now my fork is outdated. The GitHub UI will give you an indication when this happens. That indication looks something like this:
So let's get it caught up.
1. Create a new remote
We are going to use the
git remote command to do that! A
remote is pretty simple; you can think of it as a bookmark that points to a remote repository.
For example, if I run
git remote -v (the
-v flag stands for verbose) in my local copy of the Solidus fork that I created, I'll see the default remote called
origin and where it points:
$ git remote -v origin git@github.com:jacobherrington/solidus.git (fetch) origin git@github.com:jacobherrington/solidus.git (push)
You can see that there is a
fetch and a
push remote. You can ignore those for now, focus on the URL-looking thing. That's the same address we gave to git when we cloned the fork.
We can use this remote to pull in new code or push our changes up. If I run
git push, my code is going to be pushed up to this remote by default.
However, you can specify another address when you are pushing or pulling. That's what we need to do to catch up our fork.
The first step is to create a new remote:
$ git remote add upstream git@github.com:solidusio/solidus.git
This command adds a new remote named
upstream (you can choose a different name, but that's the one I prefer), pointing to the original repository on GitHub. That is, the repository that I originally forked from.
2. Pull in the new changes
Now that I've created a remote pointing at the original repo, which I like to call the upstream repository, I can easily pull in changes from that repository and push them to my fork.
First, I make sure that I'm on the master branch locally and that I don't have any weird local changes. (Careful copy-pasters, this will delete any work you have locally!)
$ git checkout master && git clean -fd
Then, I'll pull the changes from the upstream repository:
$ git pull upstream master remote: Enumerating objects: 148, done. remote: Counting objects: 100% (148/148), done. remote: Total 186 (delta 148), reused 148 (delta 148), pack-reused 38 Receiving objects: 100% (186/186), 40.44 KiB | 20.22 MiB/s, done. Resolving deltas: 100% (148/148), completed with 125 local objects. From github.com:solidusio/solidus * branch master -> FETCH_HEAD * [new branch] master -> upstream/master Updating 29acc0d0b..20973340b Fast-forward ... # some files that changed 87 files changed, 180 insertions(+), 177 deletions(-)
In this case, you can see I've picked up about 180 lines worth of changes. To update my remote fork (the repository on GitHub at jacobherrington/solidus), I'll need to push these changes up!
3. Push the changes up to your remote fork
As long as my local master branch hasn't actually diverged, it's this easy:
$ git push
You'll get some console feedback that looks something like this:
Total 0 (delta 0), reused 0 (delta 0) To github.com:jacobherrington/solidus.git 29acc0d0b..20973340b master -> master
And now your remote fork is caught up with the original repository!
That's it. 🤠.
Discussion (9)
Hi Jacob! Brilliant article, I was dealing with the same thing today.
I have another problem tho. The repo I was contributing to did not have a lot of activity and I had to make many changes and many PRs (rule was one change per commit, one commit per PR). Now I made change 'ChA' and commited 'CmA'. Then I pushed and created a PR. But the problem I guess was that the PR was not accepted very fast (as would generally happen). I move on to next change, 'ChB', commit 'CmB' and push it. But now when I try to open a PR, I am shown the previous PR (which has not yet been accepted) with both commits 'CmA' and 'CmB'. How do I keep them separate?
That sounds like you need to make each of those commits on different branches.
If you didn't make a new branch when you created 'CmB', then you might have accidentally added that commit to the same branch as 'CmA' which would put it in the same Pull Request.
Thank you for the reply, Jacob. Yes, these were all on the master branch. Do you suggest I make separate branches for each of those changes? How does that work for many changes?
What I do, is create a branch for each new feature. I usually have quite a few commits in each PR, but they are all for the same feature on what most people refer to as a 'feature branch' (meaning a branch specifically for that feature).
So if I'm going to fix some documentation, I'd make a branch from master called
documentation-fixes.
Then when I got to implement a feature, I'd make a new branch from master:
I understand now. Thanks for such detailed explanations! They really help a lot. And congratulations on the new job! :)
If I have local changes, I prefer to stash, change the tracking branch, pull, change the tracking branch back, re-apply stash, deal with any conflicts, push!!! It makes me feel comfy for some reason! I am scared of rebase.
I used to be scared of rebase, but I got used to it and now it's one of my favorite git commands. It can be scary though.
A rebase a day keeps the doctor away.
I didn't realize you could use remotes that way... but you are right - that makes keeping forks updated a LOT easier! | https://practicaldev-herokuapp-com.global.ssl.fastly.net/jacobherrington/a-fool-proof-way-to-keep-your-fork-caught-up-in-git-2e2e | CC-MAIN-2021-10 | refinedweb | 1,236 | 73.17 |
Document: WG14 N1196
Author: Lawrence Crowl
Date: 2006/10/23
Lawrence Crowl
Standard support for multi-threading is a pressing need.
The C++ approach is to standardize the current environment.
Presuming that all writes are instantly available to all threads is not viable.
The standards adopts a message memory model.
Sequencing has been redefined.
Sequencing has been extended to concurrency.
But what is a location?
Optimizers are not unaffected.
Loops without synchronization may be assumed to terminate.
All threads observe the same sequence of values for an atomic type.
Atomic operations provide acquire, release, both, or neither.
Atomic types are structs, but could be primitive types.
The types are comprehensive over the important primitive types.
Atomics may be compiled by both languages.
atomic_flag v1 = ATOMIC_FLAG_INIT; atomic_long v2 = { 1 }; atomic_void_pointer v3 = { 0 }; void func() { if ( atomic_flag_test_set( & v1 ) ) atomic_flag_clear( & v1 ); long t = atomic_load_acquire( & v2 ); atomic_compare_swap( & v2, t, t|1 ); atomic_fetch_ior_ordered( & v2, 1 ); atomic_fetch_add_ordered( & v3, 1 ); #ifdef __cplusplus long l1 = v2; v2 = 3; ++v2; v2 &= 7; v3 += 4; #endif }
Atomic operations must be lock-free to be used in signals.
Atomic operations must be address-free to be used between processes.
Sequential consistency is still not settled.
Are both conditions exclusive?Are both conditions exclusive?
x and y are atomic and initially 0 thread 1: atomic_store( &x, 1 ) thread 2: atomic_store( &y, 1 ) thread 3: if ( atomic_load( &x ) == 1 && atomic_load( &y ) == 1 ) thread 4: if ( atomic_load( &y ) == 1 && atomic_load( &x ) == 1 )
At least 5 vendors already implement the proposed facility.
Define a new thread storage duration.
Storage is unique to each thread.
Addresses of thread variables are not constant.
Thread storage are accessible to other threads.
Initialization and destruction of static-duration variables is tricky.
This problem does not exist in C.
Initiate a thread with a fork on a function call.
Join waits for the function to return.
Mutexes provide mutual exclusion.
Condition variables enable the monitor paradigm.
Thread termination is voluntary.
Thread scheduling is limited.
The thread model is based on a full C++ library implementation.
std::thread::handle my_handle = std::thread::create( std::bind( my_func, 1, "two" ) ); other_work(); thread::join( my_handle );
Locks hold a mutex within a given scope.
class buffer { int head, tail, store[10]; std::thread::mutex_timed mutex; std::thread::condition not_full, not_empty; public: buffer() : head( 0 ) , tail( 0 ) { } void insert( int arg ) { std::timeout wake( 1, 0 ); lock scoped( mutex ); while ( (head+1)%10 == tail ) if ( not_full.timed_wait( wake ) ) throw "buffer full too long"; store[head] = arg; head = (head+1)%10; not_empty.notify(); } } };
The C++ committee rejected a syntax-based approach.
The approach provided new operators for fork and join.
int function( int argument ) { int join pending = fork work1( argument ); // work1 continues concurrently int value = work2( argument ); return value + join pending; }
The rejected approach extended the set of control statements to manage synchronization.
struct buffer { int head, tail, store[10]; mutex_timed mutex; condition not_full, not_empty; }; void buffer_insert( struct buffer *ptr; int arg ) { lock( ptr->mutex ) { timeout wake = { 1, 0 }; wait( ptr->not_full; (ptr->head+1)%10 != ptr->tail; wake ) { ptr->store[ptr->head] = arg; ptr->head = (head+1)%10; notify( ptr->not_empty; 1 ); } else failure( "buffer full too long" ); } else failure( "too much buffer contention" ); };
Higher-level facilities may be built on the above primitives.
The committee has concerns that these facilities are not adequately field tests. | http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1196.htm | crawl-002 | refinedweb | 550 | 50.73 |
Random notes about life, work and play
Benoit, sorry for encouraging Mariano to release a fixed tarball for you. I should have waited until you could do it yourself, and I take full responsibility for bypassing you and not following due process.
The incentive was never anything but to have a working tarball in the 2.18.0 beta, so I hope we can still use the end result since the changes made were trivial and only affected docs.
Please reconsider banning the tarball, and again, sorry for the confusion :-)#
This is your unique chance to prove for us that the spam prevention solution set up to protect my mail address here: kjartan.maraas@pilot.oslo.kommune.no is worth the cost.
If you want to do this for the rest of the mail addresses in that domain do not hesitate to contact me on the above mail address to get a copy of our mail address database.
Thanks kindly for all your help#
Note to self: I really need to get my act together on the blog end and get myself set up with some software to help make it easy. If anyone sees a no.po file in GNOME CVS anywhere please lead me in the right direction so I can exterminate it for Joe's pleasure. #
So, four months passed and another release went out the door. I need to get into more regular blogging it seems. The real reason I'm writing this today is to get one of those fancy lookin' pirate adornments :-)
Started applying some patches for gnome-terminal this weekend and I was glad to see Dennis commited his HIGification patches too. They've been sitting in bugzilla for way too long. Also commited Alan Horkan's patch to free unused fonts early so on the whole gnome-terminal should be using less memory than ever in HEAD CVS.
On that note I think we really need to blow some life into the memory reduction work again, or at least do some publicity work since it seems to have slowed down a bit again. The wiki page is there and people should feel free to add tasks and thoughts there at any time. I think we're in better shape than ever though, so maybe that's the reason the effort seems to have been slowing down.
Going to go through bugzilla for the modules I'm involved with the most and make sure every UI and string related patch gets in early this cycle and I urge all maintainers to do the same. We've had string changes and HIG fixes sitting in bugzilla for many release cycles without getting them commited which is bad. I'm also going to drop off the all-bugs alias for a while since it's just way too much mail to handle and just becomes a time sink.
#
Got most of jhbuild running now but there are still problems:
- mozilla doesn't install the nss headers so I had to copy them
from mozilla/public/nss and mozilla/private/nss to
$(prefix)/include/mozilla-{$MOZILLA_VERSION}/nss to get
evolution-data-server to build
- librsvg fails to build with gcc4 because of -Werror being set
- nautilus-cd-burner needs a patch to work with the latest HAL
this is available in the fedora core rawhide srpm
- gstreamer doesn't build with api docs
- gal doesn't pass make install because of some problem in with the api docs
- gal installs gal.pc but evolution is looking for gal-2.6.pc
I've been trying to get a full jhbuild running for GNOME 2.12 lately and ran into a couple of problems which should be fixed now hopefully.
There are a few problems with building API docs here and there, and a couple of other issues that I have commited fixes for like broken translations and regular build fixes. Johan also commited a fix for jhbuild to use HEAD of hal and dbus for 2.12 and the stable branches for 2.10. Seems to be working just fine here at least.
I'll continue to work towards getting a full build running with no problems and file bugs against modules with problems and workarounds where I can find those.
Couldn't make it to GUADEC this year for various reasons, but I miss being there and look forward to seeing you all next time, if not earlier somewhere. Enjoy the conference! We'll be drinking beer Irish style agaian before you know it :-)#
So it looks like the 2.8.3 release went mostly ok. The 2.10.0 work definitely rocks and the wiki is really alive and cooking these days.
After 2.8.x I've spent most of my time running valgrind on GNOME and it's looking good so far. A few leaks found and some other cases of bogus memory management fixed. I also started porting some pieces away from the deprecated widgets and doing general cleanups in various modules. There's a lot of cruft all over the place that should be excised.
On the topic of header includes - we have tons of files that do
things wrong here. It would be nice if the coding style guidelines
for GNOME said something about this in my opinion.
The de-facto standard seems to be to:
#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include <glib/gprintf.h>
#include <gobject/gvaluecollector.h>
#include "gtkalias.h"
#include "gtktreemodel.h"
#include "gtktreeview.h"
#include "gtktreeprivate.h"
#include "gtkmarshalers.h"
The sparsing, valgrinding and cruft-excising tour is coming to a module near you real soon now (tm)
Update
Sven Neumann pointed out to me that using the specific
headers was ok within a library but that the catch-all headers are
the documented way to use GTK+ at least. Thanks for that clarification.
The point I tried to make was that there's room for improvement when it comes to following *any* standard from what little I've seen in CVS. :-)#
Just mailed d-d-l and r-t a diff of the package list for 2.8.3 compared to 2.8.2. It looks like we'll have another rocking release with loads of fixes etc.
There are still a few packages missing so I thought I'd post here too to get more visibility :-)
- gnome-vfs and friends need a release
- evolution and friends need a release
- control-center needs a releaseAnyone see anything else missing?
I'll try to get the release out this weekend, but I'm not sure when I'll find the time. Probably not until late sunday evening european time. We'll see...#
Another stable release on the horizon...
I've been doing a lot of valgrinding lately and I think we've gotten most of the important leaks fixed. Next step is to see if valgrind can shed some light on any of the crashes on the 2.10.0 milestone list. Tried running valgrind after enabling a11y today and that showed a lot of leakage in gok, gnopernicus, at-spi, and friends...I think there was close to 1 MB leaked after just logging in and out again...
Played another 9-ball tournament last weekend and got in 9th out of 50 or so. Pretty happy with that, but there's definitely room for improvement. Time to fire up foobillard and play, play play, play... :)
I'll nail those suckers next time...
Congrats to big N (I can see why Nat was persuaded now ;-) on the great hula launch. Definitely looking forward to seeing success in that camp...#
Picking up the pace...
It's been a while and a lot has happened since I last blogged.
On the GNOME front there was the 2.8.2 release before christmas, and since that there's been a lot of work triaging bugs and fixing stuff for 2.10.0. People have kicked serious ass and gotten the bug count down to an almost managable level, but there's clearly more triaging work left for anyone who's interested. I got myself a copy of VMWare to use for work related testing, and I'll be able to use that to test out a few of The New Kids On The Block
With regards to life in general it's been a nice and warm winter, almost no snow and around 0 degrees C for a long time now. Christmas was nice, new years too. Still three pool tournaments left this season and I need to pick up the slack there if I want to have a chance of moving up to the next division next season.
Went to a couple of concerts the last couple of months too. If want to get the best of the Norway you need to check out these two, Magnet and Thomas Dybdahl. I went to see both in december and I was totally blown away by Thomas Dybdahl. Maybe because I had no expectations when I went there, but that doesn't really matter.And finally, let's see if we can keep the frequency in this blog to something less than three months :-) #
Release is imminent!
So, we're closing in on another stable release. I want to give a big thank you to all the developers, documenters, translators, bughunters, users and other people involved in getting this release out the door. We're getting the releases out there in a timely fashion and still managing to maintain both quality and a steady inflow of new features which is a feat in and of itself. It's always a pleasure working with you guys and gals :-)
I'm off for a trip to to the countryside for a couple of days and will be back on friday. We're heading off for a relaxing couple of days here: Wolf-gang Hotell for a bit of relaxation, work related stuff and hiking, drinking and much needed socializing.
The coming weekend the series kick off with a 9-ball tournament and it's going to be fun to see how that's going to work out. I guess it'll be uphill for a couple of months before I see any results (if I get time to practice). On the bright side our club got 5th place in the european chamionship for veterans (40+) so there's inspiration to be had there...
Time to pack the fishing gear and hiking boots...
By the way, have I mentioned that Valgrind ROCKS!?#
Time flies when you're having fun I guess. Been busy lately and haven't updated this little thing called blog. Getting back into the groove at work has been hard, but I guess I've gotten rid of most of the holidayish feeling by now. Just about to start upgrading our messaging solution for 15.000 users before we roll it out to the remaining 30k so it's best to keep sharp I guess...
I've spent the last couple of weeks using valgrind and sparse on GNOME modules. This has resulted in a ton of reports in bugzilla and a load of leaks fixed. There's still loads of stuff to test and file bugs against so get to work and get stuff fixed for GNOME 2.8.0 :-)
Looking forward to getting back on track with the pool training as well. Haven't really played since before summer and I'm badly in need of practice now. The series start soon so I need to hone whatever skills I have to have hopes of getting anywhere this season. Keep your fingers crossed :-)#
This last week sure was hectic. It started off with a trip to Halden, a nice little town close to the swedish border. I played a pool tournament there and came in fourth. Really happy about that, but I guess I'll get less handicap next time around ;-) More practice and Micke won't beat me at 6UADEC :-)
We also went to a concert with a "local" band called WigWam. After reading their website I found out that they were originally from New York and emigrated to Norway in the seventies. They also entered the qualification for the european song contest to represent Norway, and I think we would have scored higher if they had won the local contest if this year's winner is the standard...
After that I went right back to Oslo on sunday to pack my bags for GVADEC. Two quick telephone calls and I had tickets for the night train and hotel room outside Kristiansand.
I really liked GUADEC this year, but since I missed the pre-conference weekend stuff it felt like it was over almost before it started. I'll try hard to make it to Boston in October to make up for that.
It's not just food and beverages that are expensive in Norway it seems. Travelling from Kristiansand to Bergen robbed me of 400 NOK for the train to Stavanger, 900 NOK for a hotel there and then 600 NOK for the boat to Bergen...should have gotten a flight from Kristiansand it seems...On the bright side, the boat trip gave me time to run valgrind against all of gnome-applets and I've got patches for quite a few leaks in there that are going into bugzilla this weekend. I'm thinking we need a new mailing list for stuff like running valgrind/memprof/sysprof and discussing how to improve stability/performance of GNOME as a whole, but I'm not sure we have the momentum to make them useful yet. Hopefully more people will want to join in on the fun :-) #
This is my first blog post#
This is Kjartan's blog! You can get it in RSS too. | http://www.gnome.org/~kmaraas/blog/ | crawl-002 | refinedweb | 2,315 | 79.09 |
8.14. Sequence to Sequence¶
The sequence to sequence (seq2seq) model is based on the encoder-decoder architecture to generate a sequence output for a sequence input. Both the encoder and the decoder use recurrent neural networks to handle sequence inputs. The hidden state of the encoder is used directly to initialize the decoder hidden state to pass information from the encoder to the decoder.
The layers in the encoder and the decoder are illustrated in the following figure.
In this section we will implement the seq2seq model to train on the machine translation dataset.
import d2l from mxnet import np, npx, init, gluon, autograd from mxnet.gluon import nn, rnn npx.set_np()
8.14.1. Encoder¶
In the encoder, we use the word embedding layer to obtain a feature index from the word index of the input language and then input it into a multi-level LSTM recurrent unit. The input for the encoder is a batch of sequences, which is 2-D tensor with shape (batch size, sequence length). It outputs both the LSTM outputs, e.g the hidden state, for each time step and the hidden state and memory cell of the last time step.
# Saved in the d2l package for later use class Seq2SeqEncoder(d2l.Encoder): def __init__(self, vocab_size, embed_size, num_hiddens, num_layers, dropout=0, **kwargs): super(Seq2SeqEncoder, self).__init__(**kwargs) self.embedding = nn.Embedding(vocab_size, embed_size) self.rnn = rnn.LSTM(num_hiddens, num_layers, dropout=dropout) def forward(self, X, *args): X = self.embedding(X) # X shape: (batch_size, seq_len, embed_size) X = X.swapaxes(0, 1) # RNN needs first axes to be time state = self.rnn.begin_state(batch_size=X.shape[1], ctx=X.context) out, state = self.rnn(X, state) # The shape of out is (seq_len, batch_size, num_hiddens). # state contains the hidden state and the memory cell # of the last time step, the shape is (num_layers, batch_size, num_hiddens) return out, state
Next, we will create a minibatch sequence input with a batch size of 4
and 7 time steps. We assume the number of hidden layers of the LSTM.
encoder = Seq2SeqEncoder(vocab_size=10, embed_size=8, num_hiddens=16, num_layers=2) encoder.initialize() X = np.zeros((4, 7)) output, state = encoder(X) output.shape, len(state), state[0].shape, state[1].shape
((7, 4, 16), 2, (2, 4, 16), (2, 4, 16))
8.14.2. Decoder¶
We directly use the hidden state of the encoder in the final time step as the initial hidden state of the decoder. This requires that the encoder and decoder RNNs have the same numbers of layers and hidden units.
The forward calculation of the decoder is similar to the encoder’s. The only difference is we add a dense layer with the hidden size to be the vocabulary size to output the predicted confidence score for each word.
# Saved in the d2l package for later use class Seq2SeqDecoder(d2l.Decoder): def __init__(self, vocab_size, embed_size, num_hiddens, num_layers, dropout=0, **kwargs): super(Seq2SeqDecoder, self).__init__(**kwargs) self.embedding = nn.Embedding(vocab_size, embed_size) self.rnn = rnn.LSTM(num_hiddens, num_layers, dropout=dropout) self.dense = nn.Dense(vocab_size, flatten=False) def init_state(self, enc_outputs, *args): return enc_outputs[1] def forward(self, X, state): X = self.embedding(X).swapaxes(0, 1) out, state = self.rnn(X, state) # Make the batch to be the first dimension to simplify loss computation. out = self.dense(out).swapaxes(0, 1) return out, state
We create an decoder with the same hyper-parameters as the encoder. As can be seen, the output shape is changed to (batch size, the sequence length, vocabulary size).
decoder = Seq2SeqDecoder(vocab_size=10, embed_size=8, num_hiddens=16, num_layers=2) decoder.initialize() state = decoder.init_state(encoder(X)) out, state = decoder(X, state) out.shape, len(state), state[0].shape, state[1].shape
((4, 7, 10), 2, (2, 4, 16), (2, 4, 16))
8.14.3. The Loss Function¶
For each time step, the decoder outputs a vocabulary size confident score vector to predict words. Similar to language modeling, we can apply softmax to obtain the probabilities and then use cross-entropy loss to calculate the loss. But note that we padded the target sentences to make them have the same length. We would not like to compute the loss on the padding symbols.
To implement the loss function that filters out some entries, we will
use an operator called
SequenceMask. It can specify to mask the
first dimension (
axis=0) or the second one (
axis=1). If the
second one is chosen, given a valid length vector
len and 2-dim
input
X, this operator sets
X[i, len[i]:] = 0 for all
\(i\)’s.
X = np.array([[1,2,3], [4,5,6]]) npx.sequence_mask(X, np.array([1,2]), True, axis=1)
array([[1., 0., 0.], [4., 5., 0.]])
Apply to \(n\)-dim tensor \(X\), it sets
X[i, len[i]:, :, ..., :] = 0. In addition, we can specify the
filling value beyond 0.
X = np.ones((2, 3, 4)) npx.sequence_mask(X, np.array([1,2]), True, value=-1, axis=1)
array([[[ 1., 1., 1., 1.], [-1., -1., -1., -1.], [-1., -1., -1., -1.]], [[ 1., 1., 1., 1.], [ 1., 1., 1., 1.], [-1., -1., -1., -1.]]])
Now we can implement the masked version of the softmax cross-entropy
loss. Note that each Gluon loss function allows to specify per-example
weights, in default they are 1s. Then we can just use a zero weight for
each example we would like to remove. So our customized loss function
accepts an additional
valid_length argument to ignore some failing
elements in each sequence.
# Saved in the d2l package for later use class MaskedSoftmaxCELoss(gluon.loss.SoftmaxCELoss): # pred shape: (batch_size, seq_len, vocab_size) # label shape: (batch_size, seq_len) # valid_length shape: (batch_size, ) def forward(self, pred, label, valid_length): # the sample weights shape should be (batch_size, seq_len, 1) weights = np.expand_dims(np.ones_like(label),axis=-1) weights = npx.sequence_mask(weights, valid_length, True, axis=1) return super(MaskedSoftmaxCELoss, self).forward(pred, label, weights)
For a sanity check, we create identical three sequences, keep 4 elements for the first sequence, 2 elements for the second sequence, and none for the last one. Then the first example loss should be 2 times larger than the second one, and the last loss should be 0.
loss = MaskedSoftmaxCELoss() loss(np.ones((3, 4, 10)), np.ones((3, 4)), np.array([4, 2, 0]))
array([2.3025851, 1.1512926, 0. ])
8.14.4. Training¶
During training, if the target sequence has length \(n\), we feed the first \(n-1\) tokens into the decoder as inputs, and the last \(n-1\) tokens are used as ground truth label.
# Saved in the d2l package for later use def train_s2s_ch8(model, data_iter, lr, num_epochs, ctx): model.initialize(init.Xavier(), force_reinit=True, ctx=ctx) trainer = gluon.Trainer(model.collect_params(), 'adam', {'learning_rate': lr}) loss = MaskedSoftmaxCELoss() #tic = time.time() animator = d2l.Animator(xlabel='epoch', ylabel='loss', xlim=[1, num_epochs], ylim=[0, 0.25]) for epoch in range(1, num_epochs+1): timer = d2l.Timer() metric = d2l.Accumulator(2) # loss_sum, num_tokens for batch in data_iter: X, X_vlen, Y, Y_vlen = [x.as_in_context(ctx) for x in batch] Y_input, Y_label, Y_vlen = Y[:,:-1], Y[:,1:], Y_vlen-1 with autograd.record(): Y_hat, _ = model(X, Y_input, X_vlen, Y_vlen) l = loss(Y_hat, Y_label, Y_vlen) l.backward() d2l.grad_clipping(model, 1) num_tokens = Y_vlen.sum() trainer.step(num_tokens) metric.add(l.sum(), num_tokens) if epoch % 10 == 0: animator.add(epoch, (metric[0]/metric[1],)) print('loss %.3f, %d tokens/sec on %s ' % ( metric[0]/metric[1], metric[1]/timer.stop(), ctx))
Next, we create a model instance and set hyper-parameters. Then, we can train the model.
embed_size, num_hiddens, num_layers, dropout = 32, 32, 2, 0.0 batch_size, num_steps = 64, 10 lr, num_epochs, ctx = 0.005, 300, d2l.try_gpu() src_vocab, tgt_vocab, train_iter = d2l.load_data_nmt(batch_size, num_steps) encoder = Seq2SeqEncoder( len(src_vocab), embed_size, num_hiddens, num_layers, dropout) decoder = Seq2SeqDecoder( len(tgt_vocab), embed_size, num_hiddens, num_layers, dropout) model = d2l.EncoderDecoder(encoder, decoder) train_s2s_ch8(model, train_iter, lr, num_epochs, ctx)
loss 0.027, 8956 tokens/sec on gpu(0)
8.14.5. Predicting¶
Here we implement the simplest method, greedy search, to generate an output sequence. During predicting, we feed the same “<bos>” token to the decoder as training at time step 0. But the input token for a later time step is the predicted token from the previous time step.
# Saved in the d2l package for later use def predict_s2s_ch8(model, src_sentence, src_vocab, tgt_vocab, num_steps, ctx): src_tokens = src_vocab[src_sentence.lower().split(' ')] enc_valid_length = np.array([len(src_tokens)], ctx=ctx) src_tokens = d2l.trim_pad(src_tokens, num_steps, src_vocab.pad) enc_X = np.array(src_tokens, ctx=ctx) # add the batch_size dimension. enc_outputs = model.encoder(np.expand_dims(enc_X, axis=0), enc_valid_length) dec_state = model.decoder.init_state(enc_outputs, enc_valid_length) dec_X = np.expand_dims(np.array([tgt_vocab.bos], ctx=ctx), axis=0) predict_tokens = [] for _ in range(num_steps): Y, dec_state = model.decoder(dec_X, dec_state) # The token with highest score is used as the next time step input. dec_X = Y.argmax(axis=2) py = dec_X.squeeze(axis=0).astype('int32').item() if py == tgt_vocab.eos: break predict_tokens.append(py) return ' '.join(tgt_vocab.to_tokens(predict_tokens))
Try several examples:
for sentence in ['Go .', 'Wow !', "I'm OK .", 'I won !']: print(sentence + ' => ' + predict_s2s_ch8( model, sentence, src_vocab, tgt_vocab, num_steps, ctx))
Go . => va ! Wow ! => <unk> ! I'm OK . => je vais bien . I won ! => j'ai gagné !
8.14.6. Summary¶
The sequence to sequence (seq2seq) model is based on the encoder-decoder architecture to generate a sequence output for a sequence input.
We use multiple LSTM layers for encoder and decoder. | http://www.d2l.ai/chapter_recurrent-neural-networks/seq2seq.html | CC-MAIN-2019-47 | refinedweb | 1,569 | 51.85 |
If you are developing for Android, you probably deal with XML files every day. These are the manifests, layouts, drawables, resource files and many others. That’s why in IntelliJ IDEA 12 we have added a new option for the code formatter, which is aware of Android-specific code styles.
The new option is available in Settings → Code Style → XML and can be enabled via Set From… → Predefined Style → Android.
For instance, the IDE inserts line breaks in layout files before any internal tag and before the first attribute, if it is not a namespace declaration.
At the same time it does not insert line breaks before string resources or colors.
You might also notice, that the new formatter preserves user line breaks and doesn’t remove them.
In Android manifest the IDE groups tags with the same name. For example, you will get a single block of uses-permission tags. Note that the IDE does not rearrange tags, it just inserts and removes line breaks to group things together.
The default behaviour of the formatter can be changed anytime you want in the settings.
Please let us know what you think about the new code formatter on our discussion forum and in our issue tracker.
Develop with Pleasure!
Great!
When can we expect UI editor for manifest file (like eclipse’s) ..
I come from the future (04/2014) and we are still waiting, so, don’t hold your breath. | http://blog.jetbrains.com/idea/2012/12/android-code-styles-in-intellij-idea-12/ | CC-MAIN-2014-52 | refinedweb | 240 | 72.66 |
I would appreciate testing of this patch. It does a couple of things: (1) It corrects an incorrect DRQ test that should have been a re-test of ATA_S_BUSY (FreeBSD-5 uses the new method). Testing DRQ is insufficient because the race that was meant to be checked was whether the interrupt was meant for us or not. Since the target may generate an interrupt and not clear BUSY for up to 100uS, if we find BUSY still set we have to wait and check again before assuming that the interrupt was not for us. (2) It emplaces a critical section around the command queueing code through to the tsleep(). While the code is supposed to be in an SPLBIO it may be possible, through a number of circumstances, for the interrupt handler to be called anyway just before the tsleep is entered, resulting in no wakeup occuring and the tsleep timing out. Note also that an ATA interrupt may have been queued prior to ata-all's disablement of the interrupt. That is, disabling the hardware bit does not necessarily prevent an interrupt from being dispatched (though it will prevent more then one, at least from the ATA device). If the interrupt is shared other interrupts may occur anyhow and execute that ata's interrupt routine. (3) Impose a mandatory 10uS delay after a new ATA command is queued, within the critical section. The target device may take that long to set ATA_S_BUSY and if we interrupt before it manages to do so we may wind up believing that the command has completed when in fact it has not yet started running. The BUSY timing is one of the biggest flaws in the ATA specification. Since BUSY is controlled by the target device, each combination of controller and target device may yield radically different timings for the bit. -Matt Index: ata-all.c =================================================================== RCS file: /cvs/src/sys/dev/disk/ata/ata-all.c,v retrieving revision 1.21 diff -u -r1.21 ata-all.c --- ata-all.c 17 Aug 2004 20:59:39 -0000 1.21 +++ ata-all.c 13 Nov 2004 08:24:51 -0000 @@ -26,7 +26,7 @@ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: src/sys/dev/ata/ata-all.c,v 1.50.2.45 2003/03/12 14:47:12 sos Exp $ - * $DragonFly: src/sys/dev/disk/ata/ata-all.c,v 1.21 2004/08/17 20:59:39 dillon Exp $ + * $DragonFly$ */ #include "opt_ata.h" @@ -53,6 +53,7 @@ #include <machine/bus.h> #include <machine/clock.h> #include <sys/rman.h> +#include <sys/thread2.h> #ifdef __alpha__ #include <machine/md_var.h> #endif @@ -609,10 +610,20 @@ if (ch->intr_func && ch->intr_func(ch)) return; - /* if drive is busy it didn't interrupt */ + /* + * If the drive is still busy then it did not generate an interrupt. + * However, there are two latency problems with ATA. First, ATA may + * generate an interrupt before it clears the BUSY bit, so we have to + * DELAY and check again. Second, ATA may not *set* the BUSY bit after + * a command is sent for upwards of 10uS or longer, leading us to believe + * that a command has completed when it has not. #2 is handled + * elsewhere, in the command queueing code. + * + * Pretty dumb, eh? + */ if (ATA_INB(ch->r_altio, ATA_ALTSTAT) & ATA_S_BUSY) { DELAY(100); - if (!(ATA_INB(ch->r_altio, ATA_ALTSTAT) & ATA_S_DRQ)) + if (ATA_INB(ch->r_altio, ATA_ALTSTAT) & ATA_S_BUSY) return; } @@ -1048,13 +1059,13 @@ u_int64_t lba, u_int16_t count, u_int8_t feature, int flags) { int error = 0; + #ifdef ATA_DEBUG ata_prtdev(atadev, "ata_command: addr=%04lx, cmd=%02x, " "lba=%lld, count=%d, feature=%d, flags=%02x\n", rman_get_start(atadev->channel->r_io), command, lba, count, feature, flags); #endif - /* select device */ ATA_OUTB(atadev->channel->r_io, ATA_DRIVE, ATA_D_IBM | atadev->unit); @@ -1069,6 +1080,15 @@ return -1; } + /* + * Disabling the interrupt may not be enough if it is shared. It can + * take ATA_S_BUSY up to 10uS to become true after a new command has been + * queued, we have to guarentee that we do not falsely assume command + * completion when the command hasn't even started yet. We also may need + * to interlock with a later tsleep() call. + */ + crit_enter(); + /* only use 48bit addressing if needed because of the overhead */ if ((lba > 268435455 || count > 256) && atadev->param && atadev->param->support.address48) { @@ -1106,10 +1126,10 @@ command = ATA_C_FLUSHCACHE48; break; default: ata_prtdev(atadev, "can't translate cmd to 48bit version\n"); + crit_exit(); return -1; } - } - else { + } else { ATA_OUTB(atadev->channel->r_io, ATA_FEATURE, feature); ATA_OUTB(atadev->channel->r_io, ATA_COUNT, count); ATA_OUTB(atadev->channel->r_io, ATA_SECTOR, lba & 0xff); @@ -1123,41 +1143,49 @@ ATA_D_IBM | ATA_D_LBA | atadev->unit | ((lba>>24) &0xf)); } - switch (flags & ATA_WAIT_MASK) { - case ATA_IMMEDIATE: - ATA_OUTB(atadev->channel->r_io, ATA_CMD, command); + /* + * Start the command rolling and wait at least 10uS for the device to + * bring up BUSY. Nasty, unfortunately, but at least the delay should + * run in parallel with the target device's processing of the command. + */ + atadev->channel->active |= flags & (ATA_WAIT_INTR | ATA_WAIT_READY); + ATA_OUTB(atadev->channel->r_io, ATA_CMD, command); + DELAY(10); + /* + * Reenable the ATA interrupt unless we are intending to wait for + * completion synchronously. Note: tsleep is interlocked with our + * critical section, otherwise completion may occur before the timeout + * is started. + */ + if ((flags & ATA_WAIT_MASK) != ATA_WAIT_READY) { /* enable interrupt */ if (atadev->channel->flags & ATA_QUEUED) ATA_OUTB(atadev->channel->r_altio, ATA_ALTSTAT, ATA_A_4BIT); - break; + } + switch (flags & ATA_WAIT_MASK) { + case ATA_IMMEDIATE: + break; case ATA_WAIT_INTR: - atadev->channel->active |= ATA_WAIT_INTR; - ATA_OUTB(atadev->channel->r_io, ATA_CMD, command); - - /* enable interrupt */ - if (atadev->channel->flags & ATA_QUEUED) - ATA_OUTB(atadev->channel->r_altio, ATA_ALTSTAT, ATA_A_4BIT); - if (tsleep((caddr_t)atadev->channel, 0, "atacmd", 10 * hz)) { ata_prtdev(atadev, "timeout waiting for interrupt\n"); atadev->channel->active &= ~ATA_WAIT_INTR; error = -1; } break; - case ATA_WAIT_READY: - atadev->channel->active |= ATA_WAIT_READY; - ATA_OUTB(atadev->channel->r_io, ATA_CMD, command); + crit_exit(); if (ata_wait(atadev, ATA_S_READY) < 0) { ata_prtdev(atadev, "timeout waiting for cmd=%02x s=%02x e=%02x\n", command, atadev->channel->status,atadev->channel->error); error = -1; } atadev->channel->active &= ~ATA_WAIT_READY; + crit_enter(); break; } + crit_exit(); return error; } Index: ata-disk.c =================================================================== RCS file: /cvs/src/sys/dev/disk/ata/ata-disk.c,v retrieving revision 1.23 diff -u -r1.23 ata-disk.c --- ata-disk.c 23 Sep 2004 11:50:03 -0000 1.23 +++ ata-disk.c 14 Nov 2004 20:53:39 -0000 @@ -462,6 +462,9 @@ u_int64_t lba; u_int32_t count, max_count; u_int8_t cmd; +#if 0 + u_int8_t status; +#endif int flags = ATA_IMMEDIATE; /* get request params */ @@ -503,7 +506,20 @@ devstat_start_transaction(&adp->stats); - /* does this drive & transfer work with DMA ? */ + /* + * DMA OPERATION. A DMA based ATA command issues the command and + * then sets up and initiates DMA. Once the command is issued the + * device will set ATA_S_BUSY. When the device is ready to transfer + * actual data it will clear ATA_S_BUSY and set ATA_S_DRQ. However, + * because DRQ represents actual data ready to roll this can take + * a while (e.g. for a read the disk has to get to the data). We + * don't want to spin that long. + * + * It is unclear whether DMA can simply be started without waiting + * for ATA_S_BUSY to clear but that seems to be what everyone else + * does. It might be prudent to wait for at least ATA_S_READY but + * we don't (yet) do that. + */ request->flags &= ~ADR_F_DMA_USED; if (adp->device->mode >= ATA_DMA && !ata_dmasetup(adp->device, request->data, request->bytecount)) { @@ -531,8 +547,7 @@ ATA_INB(adp->device->channel->r_io, ATA_IREASON) & ATA_I_RELEASE) return ad_service(adp, 1); - } - else { + } else { cmd = (request->flags & ADR_F_READ) ? ATA_C_READ_DMA : ATA_C_WRITE_DMA; @@ -540,18 +555,6 @@ ata_prtdev(adp->device, "error executing command"); goto transfer_failed; } -#if 0 - /* - * wait for data transfer phase - * - * well this should be here acording to specs, but older - * promise controllers doesn't like it, they lockup! - */ - if (ata_wait(adp->device, ATA_S_READY | ATA_S_DRQ)) { - ata_prtdev(adp->device, "timeout waiting for data phase\n"); - goto transfer_failed; - } -#endif } /* start transfer, return and wait for interrupt */ @@ -899,11 +902,14 @@ ad_timeout(struct ad_request *request) { struct ad_softc *adp = request->softc; + u_int8_t status; + status = ATA_INB(adp->device->channel->r_io, ATA_STATUS); adp->device->channel->running = NULL; - ata_prtdev(adp->device, "%s command timeout tag=%d serv=%d - resetting\n", + ata_prtdev(adp->device, "%s command timeout tag=%d serv=%d status %02x" + " - resetting\n", (request->flags & ADR_F_READ) ? "READ" : "WRITE", - request->tag, request->serv); + request->tag, request->serv, status); if (request->flags & ADR_F_DMA_USED) { ata_dmadone(adp->device); | http://leaf.dragonflybsd.org/mailarchive/kernel/2004-11/msg00158.html | CC-MAIN-2014-42 | refinedweb | 1,353 | 53.31 |
ASP.NET Core supports gRPC protocol that is about to replace legacy SOAP services with more performant and powerful protocol that is easier to use and support. This blog post shows how to build gRPC service and client on Visual Studio and ASP.NET Core.
What is gRPC?
gRPC is modern high performance communication framework for connected systems. By nature it is Remote Procedure Call (RPC) framework. It uses Protocol Buffers developed by Google as its Interface Definition Language (IDL). Using IDL the structure and payload messages are defined.
Here’s the example of RPC definition in protocol buffers IDL.
// [START declaration]
syntax = "proto3";
package tutorial;
import "google/protobuf/timestamp.proto";
// [END declaration]
// [START java_declaration]
option java_package = "com.example.tutorial";
option java_outer_classname = "AddressBookProtos";
// [END java_declaration]
// [START csharp_declaration]
option csharp_namespace = "Google.Protobuf.Examples.AddressBook";
// [END csharp_declaration]
// [START messages];
}
// [END messages]
Based on these definition files language tooling can build up client and server classes for gRPC service.
IDL of gRPC is language and tooling agnostic.
Image from gRPC homepage.
Why another communication standard if we have already REST and JSON? Well, gRPC is targeting massive scale messaging by using some fancy features of HTTP/2 and using binary wire formats for message transfer.
There are four communication patterns supported in gRPC.
- Unary RPC – client sends single request and gets back single response.
- Server streaming RPC – after getting request message from client, server sends back stream of responses.
- Client streaming RPC – client send stream of messages to server and server sends back one response.
- Bidirectional streaming RPC – client send stream of messages to server and server sends back stream of messages.
These communication patterns are not covered in any REST service specification. There’s even more covered by gRPC documentation like deadlines, timeouts and cancelling.
NB! As of writing this blog post gRPC is not supported with ASP.NET Core applications hosted on Azure App Service or IIS because HTTP/2 implementation of Http.Sys doesn’t support all features required by gRPC. It’s still possible to run applications using Kestrel on virtual machine.
Creating gRPC project on Visual Studio
ASP.NET Core supports gRPC and provides required tooling for Visual Studio.
Solution created based on gRPC Service template has only service. Adding client project is up to us. I went on with ASP.NET Core web application.
GrpcService1 is ASP.NET Core web application hosting gRPC service. It doesn’t have any UI for browsers. WebApplication1 is regular ASP.NET Core MVC application having Home controller to show message from gRPC server.
Both projects have the same greet.proto file. It is hosted in GrpcService1 project and WebApplication1 has file link to it.
GrpcService1 has minimal Startup class.<GreeterService>();
endpoints.MapGet("/", async context =>
{
await context.Response.WriteAsync("Communication with gRPC endpoints must be made through a gRPC client. To learn how to create a client, visit:");
});
});
}
}
It adds gRPC to service collection, enables routing and defines route for GreeterService. Startup class of WebApplication1 is usual ASP.NET Core MVC one. There’s no word about gRPC.
Proto buffer file greet.proto is laconic and defines just simple hello-world-style service with messages.
syntax = "proto3";
option csharp_namespace = "GrpcService1";;
}
Here’s the greeter service class generated by tooling.
});
}
}
On service side things are actually simple and thin. We don’t have much gRPC details surfacing up if we don’t actually need it.
All the ugly mess is hidden to base class of service. It’s auto-generated code we shouldn’t touch.
This code is generated based on .proto file. To have automatic service generation available in project we need reference to Grpc.Tools package.
When creating client web application is went through steps from ASP.NET Core documentation page Create a gRPC client and server in ASP.NET Core. Here is my Home controller that calls service.
public class HomeController : Controller
{
private readonly ILogger<HomeController> _logger;
public HomeController(ILogger<HomeController> logger)
{
_logger = logger;
}
public async Task<IActionResult> Index()
{
var channel = GrpcChannel.ForAddress("");
var client = new Greeter.GreeterClient(channel);
var request = new HelloRequest { Name = "Beavis" };
var response = await client.SayHelloAsync(request);
ViewBag.Message = response.Message;
return View();
}
}
It’s raw and unpolished code that just make its work. Nothing more, nothing less.
NB! In real applications we should have some client class to communicate with gRPC and to hide details like creating communication channel and service client.
Will gRPC replace SOAP, WCF, REST and JSON?
In ASP.NET Core world gRPC is new kid on the block and it’s too early to say if it’s here to replace REST and WebAPI that are easier to consume for client applications. Actually I don’t think so. Having thin and simple service interface that doesn’t require advanced tooling will remain the important benefit.
When it comes to SOAP and WCF it’s a different story. Overview of Protocol Buffers brings out the following advantages of protocol buffer messages over XML based messages:
- 3 to 10 times smaller,
- 20 to 100 times faster,
- less ambiguous.
Those who have experiences with WCF and SOAP should find these numbers great.
AS WCF is not officially supported on .NET Core then gRPC is currently the only serious option for enterprice grade messaging between systems.
Wrapping up
gRPC is a little bit similar to WCF but still a totally different beast. It is using binary format for data exchange between systems and it leads to way smaller message payloads. Using HTTP/2 features it provides four different communication patterns to support also services under heavy load of communication requests. As there’s no WCF support on .NET Core officially, gRPC is currently the best option to take when it’s about enterprise grade web services.
View Comments (2)
Are we able to host ASP.NET Core web applications in Azure yet (using PaaS services)?
On Windows based hosting not yet, as far as I know. It needs changes to HTTP/2 support in HTTP.SYS. Until it will be implemented and deployed you can host your application on Linux. | https://gunnarpeipman.com/aspnet-core-grpc/amp/ | CC-MAIN-2022-40 | refinedweb | 1,005 | 51.65 |
* (quadraticFade * 0.0001)^2
Let's look at a simple example. Here a SpotLight is placed at 300 on the Z axis, so halfway between the camera and the scene center. By default the light is emitting in the direction of the Z axis. The brightness is increased to 10 to make it look more like a typical spot light.
import QtQuick import QtQuick3D View3D { anchors.fill: parent PerspectiveCamera { z: 600 } SpotLight { z: 300 brightness: 10 ambientColor: Qt.rgba(0.1, 0.1, 0.1, 1.0) } Model { source: "#Rectangle" scale: Qt.vector3d(10, 10, 10) z: -100 materials: PrincipledMaterial { } } Model { source: "#Sphere" scale: Qt.vector3d(2, 2, 2) materials: PrincipledMaterial { baseColor: "#40c060" roughness: 0.1 } } }
Rotations happens similarly to DirectionalLight. Here we want to light to emit more to the right, so we rotate around the Y axis by -20 degrees. The cone is reduced by setting coneAngle to 30 instead of the default 40. We also make the intensity start diminish earlier, by changing innerConeAngle to 10.
SpotLight { z: 300 brightness: 10 ambientColor: Qt.rgba(0.1, 0.1, 0.1, 1.0) eulerRotation.y: -20 coneAngle: 30 innerConeAngle: 10 }
For further usage examples, see Qt Quick 3D - Lights Example.
See also DirectionalLight and PointLight.
Property Documentation
This property defines the cut-off angle (from edge to edge)th. The value used here is multiplied by
0.0001 before being used to calculate light atten. | https://doc.qt.io/qt-6/qml-qtquick3d-spotlight.html | CC-MAIN-2022-27 | refinedweb | 237 | 51.65 |
I always used to concatenate strings using the “+” operator irrespective of the language I code only to realize later that I was doing them wrong. To be precise, inefficient.
Today, we shall discuss string concatenation in python and how to do it efficiently.
A simple concatenation:
x = "hello" y = "world" print(x + y) Output: helloworld
As we are aware of the fact that string objects are immutable in python, any concatenation operation using the “+” operator could prove to be costly.
Why is it so?
String objects are immutable in python and any concatenation operation creates a new string, copies the old string character by character and then appends the new string to be concatenated.
To be clear, let me explain with an example:
def concat_strings(): """ This is a program to remove spaces in a string :return: """ *input_string = "Th is is an ex am pl ew it hs pa ce" output_string = "" for i in input_string: if i == " ": pass else: output_string += i print(output_string) concat_strings() Output: Thisisanexamplewithspace
This program removes the white spaces in a string and prints the new string without spaces. This iterates through the input_string character by character and concatenates to a new string called output_string whilst ignoring the white spaces.
Though this gets the job done this is not very efficient, Is it?
The reason for this is, on every “+” operation a new string is created(Remember strings are immutable?) every single time and the existing values have to be copied character by character.
The time complexity of this operation is O(n²). Wait…how?
Concatenation using + operator under the hood:
To get a basic idea of time complexities and space complexities, kindly refer to this article.
Let's walkthrough the example program iteration by iteration.
In iteration 1, a new string object is created and character “T” is copied to the output_string. So our new string has 1 character now.
In iteration 2, again a new string is created and this time ,“T” is copied. In addition to that, “h” is appended. This goes on for every iteration. (I have skipped the iteration for spaces for simplicity).
So what pattern do we observe here?
For every concatenation, the number of characters copied increases quadratically.
Iteration 1: 1 character (“T”) = 1 Iteration 2: 2 characters(“T”, “h”) = 1+1 Iteration 3: 3 characters(“T”, “h”, “i”) = 1+1+1 Iteration 4: 4 characters(“T”, “h”, “i”, ”s”) = 1+1+1+1
and so on till the length of the string.
If we observe the pattern, the number of copies during concatenation is 1(no of characters) + 2(number of characters) + 3(number of characters) + ….. + (n) .
This gets us to the sum of n natural numbers which is n(n+1)/2 which will give us O(xn²), where x = number of characters. Since the number of characters for every concatenation is always constant here(1 in this case) we could drop the constant factor which gives us O(n²).
The same applies for concatenation of strings of varying length as well. For concatenation of strings with varying lengths, it should be O(N + M) where N and M are the lengths of the two strings being concatenated. However, the behavior will still be quadratic based on the lengths of the strings due to repeated concatenation.
So to summarize, concatenating strings with + is a costly operation especially if string to be concatenated is long.
From the python docs:
Concatenating immutable sequences always results in a new object. This means that building up a sequence by repeated concatenation will have a quadratic runtime cost in the total sequence length.
How do we overcome this?
Well, it's better off using a list to store all the strings to be concatenated and join them using the str.join() method.
str.join() takes an iterable as an argument and returns a string which is a concatenation of all the string objects in the iterable.
def concat_strings(): *""" This is a program to remove spaces in a string **:return**: """ *input_string = "Th is is an ex am pl ew it hs pa ce" output_lst = list() for i in input_string: if i == " ": pass else: output_lst.append(i) print("".join(output_lst)) Output: Thisisanexamplewithspace
Here, we have modified our previous example to store every string into a list and finally join them. Please note that appending to lists is always O(1). So that shouldn't impact the run time of the program.
This is a more efficient way to concatenate strings rather than using a “+”. The time complexity of using join() for strings is O(n) where n is the length of the string to be concatenated.
Having said that, the difference in the execution time will be significant only if the strings to be concatenated is long. For smaller strings, we may not see a huge difference.
Note : The second example can also be written as a one liner as pointed out in the comments. This could further reduce the number of lines of code.However, the run time will still remain the same as the time-complexity of split is O(n).
def concat_strings(): *""" This is a program to remove spaces in a string **:return**: """ *input_string = "Th is is an ex am pl ew it hs pa ce" print("".join(input_string.split())) Output: Thisisanexamplewithspace
Summary:
Concatenating strings using + is not efficient.
The time complexity of string concatenation using + is O(n²)
It's always better to leverage the str.join() to concatenate strings
str.join() executes in O(n) time. | https://plainenglish.io/blog/concatenating-strings-efficiently-in-python | CC-MAIN-2022-40 | refinedweb | 915 | 62.68 |
Need to accept online payments for a React web application in a PCI compliant manner? In this article, we’ll explore Stripe and how to integrate a payment form that collects credit card information into a React web application.
Stripe is a popular online payment service. Using Stripe to accept a credit card payment is a two-step process involving the client-side and the server-side.
This article will only explore the client-side using Stripe Checkout via
react-stripe-checkout. We'll cover Stripe.js & Elements and the server-side in future articles.
Stripe offers two primary means for accepting payments on the client-side:
- Stripe.js & Elements is a foundational JavaScript library for building payment flows requiring you to build you own payment form.
- Stripe Checkout provides a simple solution to accept payments. This solution will generate a payment form for you based on how you configure it.
In order to use Stripe, you’ll need to create a free account or use an existing one. Register to create a Stripe account.
Once you have successfully submitted the registration form, you’ll be sent an email to confirm your email address and you should be redirected to the dashboard.
An unnamed account is automatically created for you. You can add more than one account to each login. How you use this ability is up to you. One organizational strategy would to have an account for each website/web app.
In the side navigation, click
Developers followed by
API keys. The API keys page will list your
publishable key and your
secret key. You’ll need the
publishable key when configuring
react-stripe-checkout.
Each Stripe account runs in one of two modes:
Live mode
Test mode
New accounts will begin in test mode. Each mode comes with its own pair of
publishable and
secret keys. In Test mode, no actual charges will be made.
Stripe Checkout
Stripe Checkout will generate a button that, when clicked, will open a modal payment information dialog. This dialog is highly configurable. The form can be configured to only collect an email and credit card information:
or it can be configured to collect billing address, shipping address, email, and credit card information:
The
react-stripe-checkout package is a thin wrapper around Stripe Checkout. It comes with a single React component that encapsulates Stripe Checkout. The component accepts almost two dozen props, most of which reflect Stripe Checkout configuration options. Only the
token and
stripeKey props are required.
Stripe uses a token-based mechanism to handle the sensitive card data. This ensures that no sensitive card data ever needs to touch your server, thus allowing your integration to operate in a PCI-compliant manner.
What this means technically is that once the user enters and submits the credit card information, Stripe Checkout will send the information to a Stripe server which then returns a short-lived token. This token effectively represents the entered credit card information. This is the reason for the
token property which is a callback that accepts the token created by Stripe and optionally accepts any address information the user may have entered.
Installation
Just add the
react-stripe-checkout package to your project using npm or Yarn:
$ npm install react-stripe-checkout
or
$ yarn add react-stripe-checkout
Usage
Using just the required props will result in a fairly plain button and payment form.
import React from 'react' import StripeCheckout from 'react-stripe-checkout'; export default class Checkout extends React.Component { onToken = (token, addresses) => { // TODO: Send the token information and any other // relevant information to your payment process // server, wait for the response, and update the UI // accordingly. How this is done is up to you. Using // XHR, fetch, or a GraphQL mutation is typical. }; render() { return ( <StripeCheckout stripeKey="your_PUBLISHABLE_stripe_key" token={this.onToken} /> ) } }
You can provide your user with a better experience by using the highly recommended props.
import React from 'react' import StripeCheckout from 'react-stripe-checkout'; export default class Checkout extends React.Component { onToken = ... render() { return ( <StripeCheckout amount="500" billingAddress description="Awesome Product" image="" locale="auto" name="YourDomain.tld" stripeKey="your_PUBLISHABLE_stripe_key" token={this.onToken} zipCode /> ) } }
With the
label prop, you can provide custom text for the initial button.
<StripeCheckout ...
With the
panelLabel prop, you can provide custom text for the “submit” button in the dialog.
<StripeCheckout amount={900} ...
If you want to experiment with Stripe Checkout and
react-stripe-checkout, then setup a Stripe account, gather your publishable and secret key, and head over to CodeSandbox where we’ve setup two sandboxes you may fork and play with. In the client-side sandbox, click
Fork and enter your publishable key. In the server-side sandbox, click
Fork and enter your secret key.
🤑 Now you can start charging your customers for your products or services. | https://alligator.io/react/payments-stripe-checkout-react/ | CC-MAIN-2020-34 | refinedweb | 798 | 56.66 |
It’s just data.
Under Channel: "Only one title, description or link is permitted." Does this mean only one of the three, or only one of each? They are all required so I'm guessing the latter. If that is the case perhaps change the language to "Only one each of title, description and link is permitted."Posted by Lance at
Correct Lance and noted. So is my use of depreciated instead of deprecated.Posted by Timothy Appnel at
I never did like the one channel per feed limitation, but since it's part of the RSS 2.0 spec anyway, I can live with it. In any case, this is redundant: "Item -- Notes: Recommended to not exceed 15 per channel." since there is only one channel.Posted by Christian Romney at
One more housekeeping item, Tim. I think "modulized equivelant" should be "modular equivalent" Thanks!Posted by Christian Romney at
Christian: Thanks and noted. I will rephrase that to read "Total number of items SHOULD NOT exceed 15."
Suggestions for inserting more standard specification language (MAY, SHOULD, SHOULD NOT) is appreciated.Posted by Timothy Appnel at
Interesting, his section on tag mappings uses a bunch of prefixes instead of namespace URIs and even better doesn't point out where one can find the docs for said elements.
PS: Exactly what is supposed to be the impact of the "RSS Core Profile" on aggregator authors?Message from Dare Obasanjo at
Christian: RSS supports any amount of channels that you want. You just have to put them in a namespace extension. For example <channels:channel>. Remember RSS supports extensions, so we can pretty much add anything we want to RSS profile.
Yes, I am joking. But also trying to make a point.Posted by Randy Charles Morin at
Sorry, Randy, but your point is lost on me. I get it, but I could just use RDF. Also, I think you're missing the point that Timothy states here when you wrote "The RSS profiles presented by Don Box and Timothy Appnel invalidate all of these three blogs. In fact, the profile invalidates most of blogosphere." I'm sure aggregators will continue to support RDF or RSSx.x in some fashion, but, by definition, the profile is forward looking. Non-compliance with the profile doesn't mean inaccessibility or deprecation. It simply means non-compliance with the profile. It is up to each individual tool author to decide how to handle non-compliant feeds. If the history of the web is any indication, I think these blogs will continue to be handled by the major aggregators. This does not mean that those who want to codify best practices should merely resign themselves to the status quo.Posted by Christian Romney at
RCM: if you had a tool which could use that information, and an example that I could follow, then I do my best to provide it.
I am not just saying this to make a point, it is something that I have consistently demonstrated over the last 18 or so months.Posted by Sam Ruby at
Dare: Good point. I was rushing a bit and tried to avoid typing out all of those URIs. I'm well aware that prefix does not necessarily map to a specific URI. I will work that into the next draft. Thanks for the feedback.
The impact on aggregator authors like yourself is better predictability. This will take time to realize will require further steps such as implementing warnings into the RSS Validator that are based on some best practices I'm trying to codify here.
Charles: You're jokes aren't funny. They are a distraction. Please stop. The point you're persisting to make is off-base (my opinion, but no one else is concuring with you either) and without creditable backup. If you're going to think outloud do it properly -- I'd love to hear it.Posted by Timothy Appnel at
Tim, my apologies. I did not mean to offend anyone.Posted by Randy Charles Morin at
After 'crossing swords' with Sam not too long ago, I was a bit hesitant to post here again, but during a private email exchange with Tim, he encouraged me to put up some questions.
Here 'tis:
1) Why, exactly, is there a [recommended] 15 item per channel limit? Why not 32, or 100? Why a limit, really?
2) Is there anything (particularly on a philosophical level) that would prevent me from linking to other rss channels within a given item within an RSS document?
With these questions, consider the following scenario:
Consider an online encyclopedia carefully architected to follow the principles underlying REST, where queries are formulated as URI's. From this, I can offer rationales that justify each of the above questions.
The rationale behind my first question would be this scenario: A result set could be sent back as an RSS file, which could conceivably return a much larger set of results than 15.
The rationale for the second question would be this scenario: A result set would be limited to not more than 15 items, but if I get, say, 20 hits for a query, then I can receive an RSS file that contains 14 items to actual results; the 15th item would be a link to an RSS file containing results 15-20.Posted by Robert Hahn at
I have a question regarding this:
"Those wishing to embed markup language or larger pieces of content in the description tag should use the mod_content module."
What happened to <xhtml:body>? Is it not going to be mentioned in the profile and is there a reason for specifically recommending mod_content over <xhtml:body>? If anything, I would be apt to recommend <xhtml:body> as the element of choice.Posted by Christian Romney at
Robert, see the RSS 0.91 spec and DTD. The limits were there in the beginning. Now imagine that you wrote a tool to that specification a few years ago. What would you do with a feed from today?
A persistent theme of my weblog writings has been extensibility. I look at this both from a producer as well as a consumer side.
As to whether the limit should be 15, 32, or a 100, I don't worry too much about that. A feed with a thousand items is valid RSS 2.0. The most you will ever see is a warning that this might be a bit excessive, and that not all consumers will appreciate what you have done.Posted by Sam Ruby at
Robert does make a good point and I take all responsibility for it appearing here. ;)
> As to whether the limit should be 15, 32, or a 100, I don't worry too much about that.
Should I strike that limit from the Core and leave it up to said profiles that use it as a foundation?Posted by Timothy Appnel at
Christian: In reviewing the previous discussion the general consensus seemed to be content:encoded over xhtml:body based on the +1's where posted.
Some reasons cited -- content:encoded was more commonly used today and was easier for publishers. xhtml:body would require authors to produce perfectly valid xhtml each time. Sadly this is the exception and not the norm for most. Jon Udell made a rare post and asked if there was room for both in order to incent tool makers to emit better (and valid) xhtml. Ironically Jon's feed breaks my RSS plugin which is why he's not listed on my I Read page. This is my bad of course because I didn't fully support namespaces as I should have and I need to fix it. thankfully the practice is not wide spread. I suspect that many more may have made the same assumption that I did. Would in-line xhtml:body element be nice? Yes, but I don't think its time is here yet. That said I'm open to allowing both.
Also keep in mind that I took a small step back from Don's work to define the core design considerations that others may be based on.Posted by Timothy Appnel at
My feeling is that every specification that has ever called itself RSS has required well formed XML. If your aggregator breaks when xhtml:body is present, then you have a bug, pure and simple. I don't mean to imply that you have to do anything but drop the bits on the floor, but your tool shouldn't spill its guts in the process.
Longer term, I would prefer to move away from grammars achieve XML well-formedness by virtue of obscuring structure via XML encoding.Posted by Sam Ruby at
I suppose I'll just come out and say I'm strongly against Timothy's core profile. The problems:
1) No namespace. Let's kill this bird dead. The profile isn't a true standard--it's kind of our 'idea' RSS document right? Well why not suggest people use a namespace? Sure nobody but a few will do it but we need to start somewhere.
2) Not enough. Timothy's core elements simply provide little gain over RSS 0.91. The plain-text description is nice but why not per-item authors? Which leads me to the third point...
3) Heavy reliance on modules. I just don't see the justification for making developers wade through a bunch of modules to get at core information like author. I also don't see much point in making consumers play the module game eg picking between dc:source, ag:source, and the like. Core functionality, and even non-core functionality like 'image', doesn't belong in modules. I'd say the heavy reliance on modules violates the Really Simple constraint.
4) Technically all RSS consumers are (contain) XML parsers and according to the XML spec there are certain things you must do like support namespaces and certain things you mustn't do like guess at the form of the document. If we're not going to set even these minimal constraints then we'll be back here in six months.
5) Please layer with other specs. Why not support xml:lang and xml:base? I thought this was in the Box profile, what's the motivation for removing it?Posted by Bo at
Timothy,
I have to concur with Sam here. I currently produce two separate feeds that use content:encoded because it was the easy way out at the time since I can't control the content directly. However, there's no real reason I can't tidy it up before outputting it as RSS, in fact, I mean to. At the very least, I'd like to see <xhtml:body> recommended on par with mod_content.
Bo,
1.) By definition a profile is a subset. A profile of RSS 2.0 that put RSS elements in a namespace would not be a subset of RSS 2.0 but an entirely different spec.
2.) By definition any profile of RSS 2.0 will probably end up looking like RSS 0.91
3.) Modules are RSS's killer app. half the interesting things that can be done with an RSS feed via RSS Bandit rely on modules (dc:date, content:encoded, xhtml;body, slash:comments, dc:author, wfw:comment, etc)
4.) What incarnation of the XML 1.0 spec says that you MUST support namespaces? This is patently incorrect given that the Namespaces in XML recommendation is about a year older than the XML 1.0 recommendation.
5.) How many RSS aggregators do you know can properly handle xml:base if it was required?
PS: When are you going to start providing an RSS feed for your blog? I'm half considering starting up a screen scraping service. :)Posted by Dare Obasanjo at
Sam: That the limit of 15 was there from the beginning I had always known - my issue was related to why that particular number?
What would I do if I wrote a tool that handled the 0.91 spec a few years ago and had to deal with a feed from today? I would do one of two things: I would either take the first 15 items and ignore the rest, or I would patch the program to become more extensible and accept more than 15 items. Evolve or die.
But the thing is, maybe the example scenario I used was never meant for the 15-item feed aggregators. Maybe I wanted to use RSS because it's a well understood format that could be viewed by an aggregator for development purposes, that contains a spec that is easy to 'view source' with, but is meant to be processed, for the most part, by completely different kinds of programs.
If the hypothetical encyclopedia I proposed was geared to all things found in the Computer Science domain, and you're writing about new things related to this area of expertise, wouldn't it be nice to be able to help new users through your writings by somehow providing them with a 'related reading' section that was simply RSS data from the encyclopedia transformed into [X]HTML?
Let me bring this back on topic. Tim is proposing, from what I understand, to codify a minimum set of constraints that all RSS feeds share in order to be considered RSS. When you want to get RSS 0.91, you add additional constraints to get the 0.91 spec.
I would propose that, since it so far doesn't seem to matter to some of us what the limit should be, that there should be no limit. Let the limits be an additional constraint inherent within the various versions of RSS.Posted by Robert Hahn at
Robert, I don't think this is the intent of the profile: "Tim is proposing, from what I understand, to codify a minimum set of constraints that all RSS feeds share in order to be considered RSS." I think that conformance to the RSS spec indicates whether or not something is considered RSS, the profile is merely a guideline for those wishing to implement what we consider to be "best practices".Posted by Christian Romney at
<OffTopic>(Apologies in advance)
Sam: Could/do you support an interface to pose questions or address comments to you that don't necessarily correspond to a previously blogged item or topic? Perhaps even something as simple as dearsam@intertwingly.net or asksam@intertwingly.net. For example, I'm curious as to how you came up with your domain name. There may be other interesting (or not so interesting) things your readers may want to get your take on. It goes without saying, of course, you would select which items to respond to... but this way we wouldn't have to pollute topics with irrelevant posts like I am doing right now.</OffTopic> :)
Robert: the number of items in an RSS feed will not affect whether or not such a feed validates. I do believe that it would be helpful if some warning were issued when the number of items is excessive.
Christian: I'll hold off on an askSam or similar feature until the flames die down. Meanwhile, you can find what you are looking for here or here.Posted by Sam Ruby at
Bo: Adding to what Dare said on your second point, this profile allows for modular extensions via namespaces which is a huge gain over RSS 0.91. With that extensibility available a whole new dimension is opened for the format. Which, to your third point, needs to be applied consistently and, in my opinion, with as few redundancies as possible for the sake of clarity.
Why not an per item author? Because a feed could be generated by an application or as part of an API where there is no author.Posted by Timothy Appnel at
Based on feedback collected from the comments on Sam's weblog I've updated the draft of the core profile....
[more]
Trackback from tima thinking outloud.
Tim, to your last point, why couldn't item:author be optional then?Posted by Lance at
Lance: Because we are trying to define a "core" that other profiles will be layered on top of. Also dc:creator exists, is in wide use and has its advantages over author.Posted by Timothy Appnel at
My comments on the outstanding issues: How to identify the profile/version? What would be wrong with this?
<rss version="2.0" xmlns:
<profile:version>1.0</profile:version>
etc. This has the benefit of allowing the RSS version to remain constant, while simultaneously identifying a feed that complies with the profile and leaving room for future iterations of the profile. I'm not stuck on the structure, just the intent.
Link: http strongly recommended.
content:encoded/xhtml:body: I say strongly recommend xhtml:body, yet allow for content:encoded. Profiles that build on the core can be more restrictive.
Christian: Interesting idea about the namespace. I like it, but judging by the number of XSLT processors reporting issues that may be problematic to implement in reality.
Your preference on content:encoded/xhtml:body is noted. I agree this is something that should drop to profiles that build on this.
That mention of content:encoded is just a footnote for those familiar with the practice of place encoded HTML in the description tag.Posted by Timothy Appnel at
great discussion at sam ruby's. tim appnel is documenting the consensus....Excerpt from romney.blog: daring to write code and chronicle the mundane at
In further proof that, petty squabbles and under-specification notwithstanding, the pervasiveness of RSS is a veritable inevitability, Cafe au Lait, one of the best resources for news on Java package releases, has added a feed. Cafe au Lait now...
[more]
Trackback from Christopher Elkins's Weblog | http://www.intertwingly.net/blog/1446.html | crawl-002 | refinedweb | 2,988 | 64.61 |
Any help on these projects is welcome (comments, use cases, design, implementation, bugspray, etc.). You can contact me at tim at keow dot org or via the Cocoon dev or users list or the xReporter list.
(I am retiring the old address, timlarsonwork at yahoo dot com)
Current Project(s)
- Form and report design GUI
Initially for Woody and xReporter, but hopefully others will find additional uses.
Involved creating the EffectTransformer. This allows the structure of the source code of Java XML transformers to match the structure of the data being transformed.
Required adding support to Cocoon Forms for dynamic creation and deletion of widgets approximately as described in this email. See below for the results thus far.
Additional topics/links:
New widget definition builder design: Email Link
Another short writeup about cforms builder logic pools:
Setup the builder's initial context.
Create a form by passing the Assistant
to the form definition class's constructor.
The form definition then asks the Assistant
for everything it needs.
The Assistant then returns the data from its
cache, queries the appropriate builder for the
data, or queries the appropriate builder logic pool.
This allows most definitions to not require specific
builder classes to be created, as the general logic to
retrieve the configuration data that they need is in the
builder logic pool.
New design for dynamic widgets, widget definition repositories, etc: WoodyScratchpad
Design for autogeneration of bindings and templates: Email Link (skip down to the part that starts: "Allow model, binding, and template fragments to be associated with each other")
New features for Cocoon Forms (Woody):
Update
The features described below are present in Cocoon version 2.1.4, but they are being redesigned at WoodyScratchpad. Please join the discussion to make sure these features get properly designed meet your needs.
Class, New, Struct, and Union
Quick summary
Combined use of these new features allow for the creation of dynamic, recursive GUI's and editors for structured content of any nesting level. See "TODO" below for current limitations in this implementation. When finished, we should be able to use Cocoon Forms to create and edit sitemaps, form definitions and templates, xreporter reports, etc.
Class
Definition element used to create a reusable collection of widget definitions.
- Template element used to create a reusable collection of templates and/or markup.
New
Definition element used to insert the widgets from a referenced class.
- Template element used to insert the templates and/or markup from a referenced class.
TODO: Should describe plans for class instantiation parameters, etc. here.
Struct
Container widget which can hold zero or more widgets.
This wraps the set of contained widgets in their own namespace (the id of the Struct widget), allowing the same widget id's to be reused multiple times in a form. Also, using a Struct widget as a Union case allows the case to contain multiple widgets.
TODO: Should describe the use of the corresponding template element here.
Union
Discriminated union widget which holds one of several possible widgets at any one time.
TODO: Should describe the use of the corresponding template elements here.
Development Notes: Watch for changes coming to this definition to experiment with various uses for this widget type, such as for the definition of subforms.
Probably going to change this from a CompositeWidget to a ContainerWidget and allow the union case to be specified by a referenced widget. This may involve allowing the referenced widget to derive its value from a general expression referencing other widgets. There is some design work left to figure out how to get deterministic behaviour from derived widgets which reference other derived widgets (order of evaluation issues). [This change has now happened, and is reflected in the detailed notes below.]
Detailed descriptions:
Class
Specify a set of widget definitions or templates and/or markup for reuse. The same concept is implemented in the form definition for widget reuse, and in the form template for template and/or markup reuse.
Definition syntax
Only allowed as a direct child widget of wd:form. Note that the definition class id's currently form a flat namespace.
<wd:class <wd:widgets> <!-- A list of any widgets(s) (e.g. wd:field, wd:new, wd:struct, wd:union) --> [...] </wd:widgets> </wd:class>
Template syntax
Inside the wd:form template, allowed anywhere other templates are allowed Note that the template class id's currently form a flat namespace
<wt:class <!-- A list of templates and/or markup --> </wt:class>
New
Insert the widgets or templates and/or markup from the referenced class.
Definition syntax
New inserts the widgets from the referenced class.
<wd:new
Template syntax
New inserts the templates and markup from the referenced class.
<wt:new
Struct
Generic container for widgets. Useful to hold multiple widgets in a union case, and anywhere there is a need to wrap a collection of widgets in a namespace.
Definition syntax
<wd:struct <wd:label>...</wd:label> <wd:hint>...</wd:hint> <wd:help>...</wd:help> <wd:widgets> <!-- A list of any widget(s) (e.g. wd:field, wd:new, wd:struct, wd:union) --> [...] </wd:widgets> </wd:struct>
Template syntax
<wt:struct <!-- A list of templates for contained widgets, possibly mixed with markup --> </wt:struct>
Union
Discriminated union. Each direct child widget is considered a union case. The widgets are only created when their case is selected (lazy construction), but their values continue to exist after switching to another case, to allow for case-switching validation, value copying between cases, and automatic support for remembering values on a switch back to a previously selected case. A container widget (Repeater, Struct, Union, or sort-of AggregateField) must be used for union cases that need to hold multiple widgets. The "case" attribute of the union element references the widget that determines the current case.
Definition syntax
<wd:union <wd:label>...</wd:label> <wd:hint>...</wd:hint> <wd:help>...</wd:help> <wd:datatype [...] </wd:datatype> <wd:selection-list .../> <wd:on-value-changed> ... </wd:on-value-changed> <wd:widgets> <!-- A list of any widget(s) (e.g. wd:field, wd:new, wd:struct, wd:union) --> [...] </wd:widgets> </wd:union>
Template syntax
The wt:union template outputs any markup outside of the cases and the contents of the wt:case template for the current union case, while suppressing output from the other wt:case templates.
<wt:union> <!-- A list of union cases, possibly mixed with markup. --> <!-- Use an empty id to handle the case of an empty union discriminant. --> <wt:case <!-- Any markup --> </wt:case> <!-- Use the union child widget id as the case id. --> <wt:case <!-- A list of any relevant templates, possibly mixed with markup. --> </wt:case> </wt:union>
Binding syntax
The wb:union binding wraps wb:case bindings. The wb:case binding that matches the current case of the surrounding union is the only wb:case binding which will perform its child bindings.
<wb:union> <wb:case <!-- A list of bindings relevant to the default case --> </wb:case> <wb:case <!-- A list of bindings relevant to the selected case --> </wb:case> </wb:union>
TODO:
- Fix issues with nested Repeater's:
- Forgetting values on Union case switch. (broken in 2.1.5, fixed in CVS)
- Finish "Form GUI" sample:
- Correct and finish the save side of the binding to allow saving the edited form.
- Add the rest of the widgets and options.
- Add display of form as it is created, possibly using frames.
- Replace the XSP success page with a JX page.
- Create samples for a form template GUI, form binding GUI, etc. and combine them into a complete form creation and editing GUI.
- Get somebody with HTML and CSS knowledge to smooth out the visual design.
- Add automatic selection list generation to the union widget definition.
Add a test to NewDefinition.resolve for union defaults that would case a non-terminating recursion.
- Make the non-terminating recursion detection more efficient.
- Verify the most useful and correct source code locations are given in exceptions.
Augment the !EffectTransformer/!WoodyTemplateTransformer exceptions with source code location information.
- Figure out what wi:* element we want to generate for wt:struct and wt:union.
- Make remaining exceptions use I18n catalogue.
Reduce object turnover in EffectTransformer and WoodyTemplateTransformer. (Should be pretty simple; replace some of the instances of out.copy() with a version out.startElement() or out.endElement() that does not create objects on the element stack, etc.)
- Consider whether widget definition classes and template and/or markup classes should stay in flat namespaces or allow nesting class definitions. (Note that class instances (wd:new, wt:new) can already nest.)
- Move definition and template classes into their own separate namespace.
- Find hotspots in the code to optimize. Currently gets very slow at about seven nesting levels. (Solved by Bruno, already mostly fixed in CVS, just one more case to handle)
- Improve the javadocs.
- Write lots of test cases.
- And hopefully much more... | http://wiki.apache.org/cocoon/TimLarson | crawl-003 | refinedweb | 1,476 | 57.27 |
The key idea of this binary search approach is to search in the last level of the tree.
If the mid of the last level is not None, then the size of last level is at least mid. We keep searching until we find the last not None leaf node, so we can know the size of the last level.
To get to the Kth node in the last level, I use the binary representation of K to track the path from root to leaf. If current bit is '1' then turn the right child, else turn right.
def countNodes(self, root): """ :type root: TreeNode :rtype: int """ if root is None: return 0 height = self.getHeight(root) last_level = 0 left, right = 0, 2**height-1 while left <= right: mid = (left+right)/2 if self.getKthNode(root, height, mid) is None: right = mid - 1 else: left = mid + 1 last_level = mid+1 return last_level + 2**height - 1 def getHeight(self, root): count = 0 while root.left is not None: count += 1 root = root.left return count def getKthNode(self, root, height, k): # binary bits representation of the root-to-leaf path while height > 0: if 2**(height-1) & k == 2**(height-1): # current bit is '1', turn right root = root.right else: # current bit is '0', turn left root = root.left height -= 1 return root | https://discuss.leetcode.com/topic/28970/o-log-2-n-using-binary-search-python-iterative | CC-MAIN-2017-39 | refinedweb | 223 | 88.36 |
. > It sounds a bit lame to leave the problem which facet is the right one > to use in the context of POSIX applications to the user. But it may be > that this is the best we can do. If it is the best we can do, I think > the poly-type approach provides a very clear and flexible solution to > this problem, while preserving the ability to implement and use hybrid > types. I agree with Shapiro that leaving it to the user is not lame at all, but preferred. It would be nice if the facets could be reached without explicit creation of the nodes, though, but it shouldn't collide with the namespace IMO. Perhaps we can reserve a character for it, and name the facets of foo.gz "foo.gz:raw" and "foo.gz:contents". Note that this is an example where saying "foo.gz:file" isn't very clear. > * What are compelling use cases for hybrid types? Any archive formats (including some image formats like tiff), many image formats (layers, thumbnails, perhaps even colourmaps as a facet), compression formats, text files(?) (auto-convert newlines to the system type). The possibilities are endless. Anything for which one might want to write a translator could be achieved with it. And what's very good: one file can have several translators bound to it simultaneously (and still be accessible in raw format as well). > * How severe are the confusions in the POSIX world introduced by hybrid > types? We need to make sure that POSIX programs don't notice it. We cannot go and change all POSIX programs. For them, we have to design a system to reach the facets without them noticing it's just the same file. This may or may not be the same system which is used by programs which do know about the facets. > * How complex is the problem how hybrid types should be perceived by > legacy applications? Is it multi-dimensional and/or context-sensitive? > Are there reasonable default resolutions? There are no reasonable defaults, and the decision should IMO be up to the user. That makes it pretty simple from a programmer's point of | http://lists.gnu.org/archive/html/l4-hurd/2006-02/msg00007.html | CC-MAIN-2015-27 | refinedweb | 361 | 74.49 |
How does one learn to be a Carrara programmer?
edited December 1969 in Carrara Discussion
May seem an odd question, but I've just been so blown away by what some of the plugin creators have been able to create for Carrara, and I wondered what the process is, or how one would start down the road of learning programming so that eventually somewhere down the line if there's something I wanted to add or fix in Carrara I could maybe do it myself (that's the pipe dream, anyway). I know nothing about programming at all, but I figure it's got to be a learned skill like anything else, right? Probably there's years of schooling and studying that goes into it, but where does one start, and what skills specifically would someone need to learn to become proficient/skilled at coding specifically for Carrara?
Jonstark,
First, I have written 0 lines of code for Carrara, so take this with a grain of salt. The Carrara SDK is a set of libraries that allow your program to interface to Carrara. The programs are written in C++ (I believe it may be c+ or c#). So first, you need to learn to program in C++. The SDK will then allow interfacing between your code and Carrara.
Go ahead and download the SDK. There are some pdf files along with libraries and sample code that should get you started.
ncamp
That has nothing to do with animation, it is pure data processing!
I understand that they are long too much in making evolve the software but one must wait until they finished some with their Genesis…
The DAZ forums use to have a forum just for the SDK. It's archived here. Maybe useful to pour over...:
Jon, I tried to PM you but it seems to be broken(?). Since there is no SDK forum anymore I wanted to invite you to host an SDK/author Group at Cafe.
Cafe Groups have an Activity wall (like a BBS crossed with Facebook) and their own dedicated forum.... I was thinking, if you just sort of shared your progress, and if some of the existing developers were invited to participate..., Fenric has always been very free with information. I'm pretty sure he would be willing to participate.... For me it is much easier to learn if I have people to discuss it with and someplace to post progress.
I hope you will consider it.
Cheers!
Hey Holly, thanks I actually did just receive the PM (I also had thought the PM system was broken, but a forum mod advised that you actually have to select the checkbox to view sent messages before you'll see your messages appear in your sent messages folder.... weird).
I will definitely make use of any resource for sure, and thank you for the link, didn't realize that was on the Cafe. However I don't have any programming skills or experience or background, so I'm starting from zero, so I certainly don't have much to offer yet :) I don't really even know how to conceive of how herculean a task this might be. Sounds like from ncamp mentioned (thanks ncamp!) my first step is to learn C++ which I think I can probably go to a local bookstore to pick up a book on C++ to get started, and then I'm guessing once I start to learn/master the language C++ I'll know better what I'm looking at in the Carrara SDK (Software Developer Kit, I just googled to try to figure out what that stood for as I've never known before :) )
I used to do some programming many moons ago, and you are right that it is a learned skill like any other. A logical and analytic mind will help! The only advice that I can really offer is to take it methodically and start simple, rather than aiming too high, too soon. I wish you luck with this endeavour, I am sure you will get a lot out of it.
You'll have to start by learning C++. Start off small, and learn the basics first: there are lots of good tutorials around on the web, and Visual Studio Express is a free download from Microsoft. Get a basic familiarity with the syntax and structure of the code, and the basic workflow for using it.
As others have mentioned, you download the SDK from DAZ. There are examples and documentation for the basic operations which are reasonably good - most things are covered somewhere (though not always obviously). All that is enough to get you started with basic modifiers, commands, tweeners, and shaders - modify the SDK samples, and learn how Carrara does things.
Now, a lot of what I do for my plugins these days involves running the resource de-compiler on the base Carrara components and extracting string values from the DAZ .mcx files in order to find the things they DON'T have in the documentation. I'll save out Carrara files un-compressed and look through them for keys and values, and I do a lot of experimentation. But I've got a bit of a head start on you: I got my first computer in third grade (TRS-80 ColorComputer 2) ((33 years ago... ack!)), and I've been writing programs ever since. And it's been my full time job for 18 years now. :D
Fenric, you're a blessing for Carrara users.
Just to let you know what you are getting in to:
Here is a simple example of a C# code which is in the C family they are both Object Orientated Programming. They just have a few structural and functional differences.
meaning they use Methods, Functions and Objects. Which you actually get an example of in Carrara when it shows instance and object. It works like code in OOP.
This example is to simply compare a few numbers and list them from smallest to largest. So you really need to like to stare at a computer screen with code on it for hours and hours. and be ready to pull your hair out.
If you are (I actually love to program) then as stated their are a lot of good video tutorials and code samples.
public class MathFunction
{
//main method begins execution of C# application
public static void Main(string[] args)
{
int number1; //Declares the first integer
int number2; // Declares the second integer
int number3; // Declares the third integer
int sum; // sum of the three numbers
int average; // average ot the three numbers
int product; // this will be the product of the 3 numbers
int largest; // this is the largest number
int middle; // this is the middle integer
int smallest; // this will be the smallest
//prompt the user and reads the first integer
Console.Write("Lets compare some Integers \nEnter First Integer: ");
number1 = Convert.ToInt32(Console.ReadLine());
//prompt the user and reads the second integer
Console.Write("Enter Second Integer: ");
number2 = Convert.ToInt32(Console.ReadLine());
//prompt the user and reads the third integer
Console.Write("Enter Third Integer: ");
number3 = Convert.ToInt32(Console.ReadLine());
// gets the total sum of the three numbers
sum = number1 + number2 + number3;
product = number1 * number2 * number3;
// get the average of the three numbers
average = sum / 3;
largest = number1;
middle = number1;
smallest = number1;
if (largest < number2 ) // compares for largest
largest = number2;
if (largest < number3) // compares for largest
largest = number3;
if (smallest > number2) // compare for smallest
smallest = number2;
if (smallest > number3) // compares for smallest
smallest = number3;
if (middle > number2) // compare for middle integer
middle = number2;
if (middle == smallest ) // compares for middle integer
middle = number3;
Console.WriteLine("These are our three numbers: {0}, {1}, {2}.",number1 ,number2 ,number3 );
Console.WriteLine("This is the sum of those numbers: {0}.", sum);
Console.WriteLine("This is the product of those numbers: {0}.", product );
Console.WriteLine("This is the average of those numbers: {0}.", average );
Console.WriteLine("This is the largest: {0}\nthis is the middle {1} \nthis is the smallest {2} ", largest,middle, smallest);
Console.Write("Press enter to end.");
Console.ReadLine();// added to hold program open to see display
}// ends main
}// end class compairson
Lol, I wasn't expecting that next week I would be all caught up to your skill level... it would definitely take me at least 2 weeks to catch up :)
Thanks for the tips, sounds like my first step is learning C++, so I'm going to focus on that first and see how it goes. Just to clarify my understanding, I thought there were portions of Carrara that are 'locked off' and that even developers can't see/access, or am I wrong about that? And if there are 'forbidden areas' in the Carrara coding, I wonder what kinds of things are forbidden.
Also aside from C++, are there any other coding languages that come into play in Carrara that would be helpful to learn? I'm guessing if someone wanted to create a plugin that allowed Carrara to render with a different render engine, and the other render engine was in a different language, then mastery of both languages would be necessary? Yeah, you can probably tell from my questions that I don't have a clue what I'm even talking about :)
Seems like a place to start though, so for right now I'll put in some time to learning C++ (I'm assuming that a complete coding novice can learn C++, and there's no other coding thing/language/etc that I need to learn first?)
Thanks again for all the helpful answers :)
C++ is a fine place to start although there are a few newer languages C# for example they are both OOP's so they will work similarly. Stick with learning one to start then when you get a good feel for it you will find many modern languages are readable and understandable. So if you wanted to say write code for a web page yo could look at Java or PHP for example.
Just work on fundamentals first what a class is what an instance is what a method is. This will carry you far in the OOP world of programming.
and this is great form of programming because it can link code together that you write even if you wrote it at different times. it's a great type of code. Everything is modular.
Jonstark
Not to discourage you, but to encourage you.
I started off with 2 years of Java programing in College, then moved to web design, html, to javascript, to php, to actionscript, to flex, now working with Away3D for actionscript. Fun stuff the last two. Much more visual.
Learning one language helps you learn others faster.
However, I think if I had the time I would like to learn Python. Suppose to be easy to learn, and would love to use it with the Pycloid plug in. to make some great animations.
I took a free Artificial Intelligence course through MIT that they offer, and they recommend learning Python to test out their examples, because of its short learning curve.
Or I'd like to learn to program the Arduino micro processor, and hook my smart phone to everything in my house! Heck, even 10 year olds are learning to program these chips.
But personally, if I were to recommend a quick way to learn programing I would suggest ActionScript3. Fun visuals while you learn.
I think any of the languages you suggested are fine languages to learn . But... He wants to learn to create plug ins for Carrara. So he will need to write in C++ I expect. Based on its age and function, based on what I have read this is the language it should be in. If he learns other languages first yes it would make it easier to learn but he would still have to learn the differences by learning C++ as his first he kills the proverbial two birds with one stone. That is one of the great advantages of C# through the software that Microsoft uses if Carrara was written in C# you could write the code in many different languages of your cchoosing and the middleware would take care of making it work together.
This is what makes it one of the more modern languages.
As to the Arduino processors. You are correct they are as easy as anything they are still OOP based programming and there are many different manufactures of PIC type programmable processors. The code is simple written in a loop class that is part of the overall code. I work with PLC systems and write code in Ladder Logic, scripting languages and Pascal type code in my job. I am starting to look toward using PIC (Embedded systems) I am looking at Microchip simple because they have several options I can use. I am looking more toward the embedded systems now because I can create not just the software but design the boards as well than have a PCB service create professional boards.
They also offer free software that allow you to setup an HMI type of interface on an Android device to control the device. As you stated being able to control everything in your house from your smart phone.
Hey guys, maybe you can give me some guidance here. In my career I've written and debugged some code in IBM mainframe assembler, cobol, PL1, and other mainframe languages, but that was decades ago and I'm not a "serious coder" by any means.
More recently I did some C++ coding back in the early 00's when studying for my MS degree, but that was all "CMD Window" type coding with no visual elements. Those mainframe programming languages above are "procedural" in nature, not object oriented. So for me, my masters degree C++ projects were very difficult not because of the language syntax, but because of the different way one's brain has to think.
I would like to do some more C++ development for windows with all the normal Windows visual elements such as resizable windows, menu dropdowns, etcetera. Eventually, it might be nice to write plugin code for Carrara but that's not really my first priority.
Can any of you suggest any resources for training myself to think in terms of OOP? I think for me, that's probably where I need to begin...in "brain school." :lol:
There is a free book, Thinking in C++ by Bruce Eckel
I'm far from an expert but if memory serves this used to get some recommendations a few years ago (give or take a decade; where did all that time go).
.
First OOP is not meaning it is visually driven. It has more to do with the fact that it doesn't have ( like old code programs) Line number references or specific calls to subroutines. it is written as modules that it all it is referencing to. although you can use visual aspect type with an IDE program that will allow you to place items easier using a pre-created window or button.
The Object is referring to the fact that a person writes a code class for an air plane this is his object it is a blue print for all the instances of the object. When you write a program you can call on that code and use as part of your code or you could write an add on for that code and add something to it without damaging the code he wrote. Which is where the SDk’s come in. this is the decompiled code that you can actually look at the code and make modules that will work with the existing code.
one last thing is the command window programming is what you still do even if you are working visually. Example you put a button on the screen in the IDE. Yes the button is visual but you switch to a command type screen to make your function work. The code that is needed to create the button is already created for you but you must add the command lines to make the button do what you want it to. So you never get away from writing code in a command window environment
And yes programming isn't for everyone, this isn't even an intelligence thing. I know intelligent people who could write great code if they wanted to program but they never will because they hate the thought of sitting that long working on that type of problem.
A good place to start is U-tube there are a few good courses on there that have step by step how to write basic C++ or C# code. Download the Visual studio free version ( it just doesn’t have as many added modules for code as the pro version) just get the one you want to learn C++ or C#.
Hey, things have come a long ways since college. I'm going to have to take a look into this. Thanks Paul.
I have quite a bit of experience working in OOD/OOP (mostly Borland Delphi and Ada, but some in C++), and once even thought of developing a plug-in idea that I have had since starting with Carrara. I downloaded the SDK, then noted the guide (at the time) was sparse and old, and decided I was not up to the challenge yet. I wish I had 3-4 months to spend digging into the system to figure out how it works, but I don't have the time. The point is (as Fenric alluded to) that even after getting over learning C++, you still have the Carrara SDK learning curve. I suspect it is more formidable then the language curve.
Also, Jon, I don't think it was mentioned, but you'll need a compiler to convert your C++ code into machine language that will work with Carrara. I am not sure which compilers are compatible with Carrara. I assume MS Visual C++ is what Carrara is written in. But which other compilers will generate code to work as a plug-in? Maybe someone with experience writing Carrara plug-ins (like Fenric) can answer that.
I don't mean to dampen your motivation or spirit, just clarify the hurdles ahead. To be totally honest, I wish you a lot of luck!
Hey, I never thought of HTML and Java being coding languages, I learned a lot of HTML and a little java already (self taught in building webpages, pop up tables forms, etc for an online business I used to be involved in a few years back). That was pretty easy and logical once I got the hang of it, so if that counts at all, it gives me a smidgen more confidence going in.
Not looking to make a career or anything, just a little more ambitious about maybe 'peeking under the hood' of Carrara and seeing if I can contribute (possibly not), so I'm approaching this again from the perspective that all of this is just a hobby, and have started finding books (some paid for on amazon, other free ones, thanks for the tip on 'Thinking in C++', getting started there as it's a cost free way to start :) ) and will start making my way forward (if I can).
I was always afraid of ever going in the modeling room in Carrara up til just a couple of weeks ago, when the polygon thread got started, and thought I would finally venture in, and while I'm no master modeler yet, it is easier and less complicated to pick up than I envisioned it would be, and I'm actually really enjoying it. It might be (probably is in fact) that this has given me way too much overconfidence to tackle other unrelated things I have always wondered about, so I hope no one is envisioning or expecting that in a month or too Jonstark will have a new unbiased render engine for Carrara ready to go that will render the most complicated scenes in just a few seconds with perfect clarity, or anything like that, because honestly nothing may come of this at all and if it does it's more likely that I'll come up with an extra checkbox in the render settings to turn off SSS, or something small (but hopefully useful) like that. For now I'm just going to start diving into C++ in my free time and see if it starts to make sense to me. Once (if) I gain a functional knowledge of the language, then I can take a peek at the SDK for Carrara and see what I can make of it (at least I should have an understanding/idea of how high a mountain would have to be climbed, lol). I guess I'm becoming a bit obsessed with Carrara, and what I've read so far of C++ I find kind of fascinating, so... we'll see, but so far I'm not dismayed.
But I thank you all for giving me a place to start: with C++ :)
For the Windows compiler, just use Visual Studio. You just won't be able to support Windows XP anymore.
The original place where developers would hang out was this group on Yahoo-
Pretty quiet now. Those were the days, when there was active participation of the original architects and coders!
Yahoo says that's a closed membership group, can't see anything.
Hey, things have come a long ways since college. I'm going to have to take a look into this. Thanks Paul.
No problem, glad I can contribute a few skills and information to help. Because when it comes to programming I have spent a life time programming various languages and styles.
Because when it comes to Daz 3d and Carrara I'm the Noob asking questions. That why when the original question came up I didn't worry to much about the fact of saying you know you have to spend hours looking at a computer screen. Because you have to do that with Carrara to.
After spending 15 minutes typing a flipping post to this thread, I completely lost the entire text. Thanks, DAZ, for the buggy forum site!
Bottom line of what I lost:
Jon, I suggest you start by downloading and installing Python and PyCarrara (both free) and learning that plug-in first. I think you'll find that it is amazingly versatile and Python gives you a lot of capability. It might be worth the 2-3 weeks of time it takes to get the essence of this powerful plug-in.
Then, if it doesn't suit your needs, then go to writing your own.
Huh. It is still there (I can see the posts)... I wonder who the owner is, and if they are still monitoring the group? Did you request to join?
Again, inviting you guys to start a group at Cafe:
It has a BBS "activity wall" and a dedicated forum....
Getting the community a groups option was the whole reason I got involved at Cafe. info here tends to get lost pretty quickly. With a dedicated group hopefully useful discussions (and links like here) can find a homebase.
Holly --indeed the forum threads way of keeping up with things is really easy to lose track of stuff. Groups are better for sure. I signed up for one just to get some support over at Carraracafe . I guess we should start a few.
Rich
Maybe I should just go ahead and try to create a group for programming in Carrara? I know nothing, as of yet, so not certain I should be the one to start it as I will have literally nothing to contribute initially, but maybe that shouldn't matter as long as it's started?
Yeah... sorry to be a nag :P I assume a lot of people would just be starting out, so even the most basic info like links and such are a good place as any to start.... I know it's out of the way (if you don't go there)..., and the newer Cafe features are still evolving (as I put in feature and bug requests).... But at least people might not have to start over at zero every time?
Anyhoo, you could be like our Luke Skywalker..., innocent at the start, but getting more skilled as he goes along. :cheese: HERO'S JOURNEY!
Jonstark
-sure go ahead and start one(group) at least then maybe a few folks will start to see it and maybe get something going. I do not wish to put a damper on your adventure but C++ programming within a 3d application is not going to an easy learn. That said ---if you have the yearning and the time --go about it.
There are a host of spots to start learning C++ and a number of good books so resource wise ---its available so best of luck man.
Just remember this is a years time frame to get proficicent its not a months thing...its that much stuff to ingest.
Smiles.
Rich
No, it's hardly easy. But a lot if the things that can make programming hard are taken care of for you when you are in a plugin environment. The "business" end of things is far more important - the idea, the need you are filling, and your proximity to that need.
The most painful plugins I have are the two I do not personally use. Interestingly, they are at the two ends of the spectrum as far as coding complexity.
MDD format has nothing interesting at all from a coding standpoint: it is a matter of dumping data out to a file. But I don't own or use the applications that most people want to use it with, and so support is always a painful process of trial and error
ERC is by far the most algorithmically complex plugin I've written. I am relatively certain that each operation does what I expect it to, but I couldn't tell you why you would want most of them. I see the same sort of operations available in Maya and Faba asked specifically for some of them, but the fact remains that as a non-animator, I have yet to ever use the thing myself.
So: find a need and fill it... But give preference to things that YOU need | https://www.daz3d.com/forums/discussion/comment/441666/ | CC-MAIN-2021-17 | refinedweb | 4,434 | 68.1 |
Node:Closing files at a low level, Next:Reading files at a low level, Previous:Opening files at a low level, Up:Low-level file routines
Closing files at a low level
To close a file descriptor, use the low-level file function
close. The sole argument to
close is the file descriptor
you wish to close.
The
close function returns 0 if the call was successful, and -1
if there was an error. In addition to the usual file name error codes,
it can set the system variable
errno to one of the following
values. It can also set
errno to several other values, mostly of
interest to advanced C programmers. See Opening and Closing Files,
for more information.
EBADF
- The file descriptor passed to
closeis not valid.
Remember, close a stream by using
fclose instead. This allows
the necessary system bookkeeping to take place before the file is
closed.
Here is a code example using both the low-level file functions
open and
#include <stdio.h> #include <fcntl.h> int main() { char my_filename[] = "snazzyjazz17.txt"; int my_file_descriptor, close_err; /* Open my_filename for writing. Create it if it does not exist. Do not clobber it if it does. */ my_file_descriptor = open (my_filename, O_WRONLY | O_CREAT | O_EXCL); if (my_file_descriptor == -1) { printf ("Open failed.\n"); } close_err = close (my_file_descriptor); if (close_err == -1) { printf ("Close failed.\n"); } return 0; }
Running the above code example for the first time should produce no
errors, and should create an empty text file called
snazzyjazz17.txt. Running it a second time should display the
following errors on your monitor, since the file
snazzyjazz17.txt
already exists, and should not be clobbered according to the flags
passed to
open.
Open failed. Close failed. | http://crasseux.com/books/ctutorial/Closing-files-at-a-low-level.html | CC-MAIN-2017-43 | refinedweb | 282 | 66.33 |
18 November 2011 05:06 [Source: ICIS news]
By Becky Zhang
SINGPORE (ICIS)--?xml:namespace>
The price spread between PTA and PX has narrowed to $90-110/tonne (€67-81/tonne) in November, compared with $300-400/tonne seen in January to April 2011, according to ICIS. (Please see price chart below)
“If the situation remains, a larger scale of production cutbacks is expected across
A minimum spread of $150-180/tonne is required for most Asia PTA producers, market sources said, but added that newly built plants in
“The current poor margins are rooted from the downbeat sentiment, rather than market fundamentals,” said another northeast
Concerns about the eurozone debt crisis and weakness in the
The bearish sentiment is being exacerbated by a domestic credit crunch in
PTA is a raw material used in the manufacture of polyester, which is mainly used in the textile industry.
“It is of little hope that our margins to improve markedly in the next three months,” said the second northeast Asian PTA producer.
Negative margins for PTA makers were last recorded in the first five months of 2009, when the world economy was in the grips of recession.
Some PTA producers have brought forward the turnaround schedule for their facilities, given poor market economics.
“No point to keep running a [PTA] plant, if it is making loss[es],” said a major southeast Asia producer said.
The producer said it plans to introduce a cost factor into contract formula for next year’s term negotiation as the current spot price-based formula is not able to protect its margins.
CAPCO shut its 250,000 tonne/year No 2 plant indefinitely at the end of October, and also shut its 400,000 tonne/year No 5 unit for five days on 9-13 November.
On 14 November, the company took its 250,000 tonne/year No 4 unit off line for an indefinite period.
Sam Nam, on the other hand, shut its 350,000 tonne/year No 1 QTA (qualified terephthalic acid) on 28 October. It initially planned a month-long shutdown, but decided to extend the period to two months up to end-December, said a company source.
Early this month, Sinopec Shanghai Petrochemical shut its 350,000 tonne/year PTA unit for a month of maintenance, while Sinopec Yizheng Petrochemical took its 350,000 tonne/year No 1 PTA unit off line on 10 November for a three-week shutdown, said a source from Sinopec.
Mitsubishi Chemical shut one of its two 330,000 tonne/year units in
In
Also in
Zhejiang Yuandong Petrochemical is also mulling cut operating rates at its three PTA units, with a combined capacity of 1.8m tonnes/year, but would like to monitor the market for another couple of weeks, said a company source.
The recent plant shutdowns affect some 6.37m tonnes/year of regional supply in November, representing 15% of
In
PTA producers in the region are competing for feedstock PX, which is currently in short supply, said a third major northeast Asian producer.
If PTA makers cut their PX contract volumes for the rest of 2011 because of production cutbacks, this will weaken their power to negotiate for PX contracts next year, he said.
“If it is not the fourth quarter, we shall have already reduced our operating rates,” he said.
Source: ICIS
Asia PTA shutdown and output cuts in November and December
($1 = €0 | http://www.icis.com/Articles/2011/11/18/9509453/asia-pta-makers-mull-extra-output-cuts-in-dec-on-poor-margins.html | CC-MAIN-2014-10 | refinedweb | 571 | 52.73 |
Conway's Game of Life in Python:
- Overpopulation: if a living cell is surrounded by more than three living cells, it dies.
- Stasis: if a living cell is surrounded by two or three living cells, it survives.
- Underpopulation: if a living cell is surrounded by fewer than two living cells, it dies.
- Reproduction: if a dead cell is surrounded by exactly three cells, it becomes a live cell.
By enforcing these rules in sequential steps, beautiful and unexpected patterns can appear.!
Here I'll use Python and NumPy to compute generational steps for the game of life, and use my JSAnimation package to animate the results.
Because the Game of Life is so simple, the time step can be computed rather
tersely in Python. Here I implement two possibilities: one using generator expressions,
and one using the
convolve2d function from
scipy. Note that neither of
these are extremely performant: they involve creating several temporary arrays,
and will not work well for large problems with many time steps. Nevertheless,
the simplicity makes these functions very attractive, and they are absolutely sufficient
for the small examples we'll consider here:
import numpy as np def life_step_1(X): """Game of life step using generator expressions""" nbrs_count = sum(np.roll(np.roll(X, i, 0), j, 1) for i in (-1, 0, 1) for j in (-1, 0, 1) if (i != 0 or j != 0)) return (nbrs_count == 3) | (X & (nbrs_count == 2)) def life_step_2(X): """Game of life step using scipy tools""" from scipy.signal import convolve2d nbrs_count = convolve2d(X, np.ones((3, 3)), mode='same', boundary='wrap') - X return (nbrs_count == 3) | (X & (nbrs_count == 2)) life_step = life_step_1
Note that we've made a choice here about the game boundary. Classically, the game takes place on an infinite, flat plane. Here, for simplicity, we've used a torroidal geometry (likely familiar to players of 1980s computer games like Asteroids), where the grid wraps from top to bottom and left to right.
Now we'll use the matplotlib animation submodule to visualize the results
(for a tutorial on matplotlib animations, see my previous post
on the subject). We'll make use of my
JSAnimation package, which you
can read about here.
%pylab inline
Populating the interactive namespace from numpy and matplotlib
# JSAnimation import available at from JSAnimation.IPython_display import display_animation, anim_to_html from matplotlib import animation def life_animation(X, dpi=10, frames=10, interval=300, mode='loop'): """Produce a Game of Life Animation)
Let's give this a try with a random starting field:
np.random.seed(0) X = np.zeros((30, 40), dtype=bool) r = np.random.random((10, 20)) X[10:20, 10:30] = (r > 0.75) life_animation(X, dpi=10, frames=40, mode='once')
With the above random seed, the cells die off after about 40 generations. In the process, some very interesting patterns show up: there are static patterns, oscillating patterns, and a lot of spontaneous symmetry. Let's explore a few of the well-known patterns here:
Several static configurations are known: some of the smallest static units are shown here. We'll generate a few frames just to show that they are in fact static.
X = np.zeros((6, 21)) X[2:4, 1:3] = 1 X[1:4, 5:9] = [[0, 1, 1, 0], [1, 0, 0, 1], [0, 1, 1, 0]] X[1:5, 11:15] = [[0, 1, 1, 0], [1, 0, 0, 1], [0, 1, 0, 1], [0, 0, 1, 0]] X[1:4, 17:20] = [[1, 1, 0], [1, 0, 1], [0, 1, 0]] life_animation(X, dpi=5, frames=3)
An oscillator is a pattern that returns to its initial configuration after some number of steps. The static patterns shown above could be thought of as oscillators with a period of one. Here are two commonly-seen period-two oscillators:
blinker = [1, 1, 1] toad = [[1, 1, 1, 0], [0, 1, 1, 1]] X = np.zeros((6, 11)) X[2, 1:4] = blinker X[2:4, 6:10] = toad life_animation(X, dpi=5, frames=4)
More complicated oscillators exist. Here's a period-three oscillator known as "The Pulsar", which displays some appealing symmetry.
X = np.zeros((17, 17)) X[2, 4:7] = 1 X[4:7, 7] = 1 X += X.T X += X[:, ::-1] X += X[::-1, :] life_animation(X, frames=6)
There are other classes of object which oscillate, but also move while oscillating. One of the earliest seen is the "Glider", which after 4 steps returns to its initial configuration, but shifted by one cell in both the x and y direction. This is a configuration that often emerges from random starting points.
glider = [[1, 0, 0], [0, 1, 1], [1, 1, 0]] X = np.zeros((8, 8)) X[:3, :3] = glider life_animation(X, dpi=5, frames=32, interval=100)
An early question posed about the Game of Life was whether any configurations exist which result in asymptotically unbounded growth. It was quickly found that the answer was yes. Though it wasn't the first discovered, the following is one of the most compact configurations which display unbounded growth. Note that this claim is precisely true only on an infinite game board: using a torroidal (i.e. wrapping) geometry like we do here will lead to different results, but the first several hundred generations are unaffected:
unbounded = [[1, 1, 1, 0, 1], [1, 0, 0, 0, 0], [0, 0, 0, 1, 1], [0, 1, 1, 0, 1], [1, 0, 1, 0, 1]] X = np.zeros((30, 40)) X[15:20, 18:23] = unbounded life_animation(X, dpi=10, frames=100, interval=200, mode='once')
The earliest known instance of unbounded growth is one of my favorite configurations: the "Glider Gun" discovered by Bill Gosper. It is an oscillating pattern that creates an infinite series of gliders. It still amazes me that something like this can even emerge from Conway's simple rules, but here it is. We'll stop after a couple hundred frames, but given an infinite game board this action would go on forever:((50, 70)) X[1:10,1:37] = glider_gun life_animation(X, dpi=15, frames=180, interval=50, mode='once')
Note that while the code above is well-suited for small explorations, it is probably not sufficient to do very large and long game of life computations. For that, I'd recommend Golly, an open-source cross-platform package for computing and visualizing the Game of Life. It has some nice optimizations, including a blazing fast hash-based computation of generational steps for long-lived problems.
Diving further in, you might come across other very cool patterns. One pattern, known as a "Breeder", moves through space creating glider guns, which in turn create an endless series of gliders. Wikipedia has a great animation of this in action:
Notice the series of glider guns, similar to the one we built above. While this animation could certainly be created using the above Python code, I'm just not sure I'd have the patience!
Despite (or perhaps because of) its simplicity, the Game of Life has inspired an entire community of people who study its properties. It has influenced fields as diverse as mathematics, computer science, biology, epidemiology, and sociology. This interest has led to the discovery of configurations with some very surprising properties. Incredibly, it has even been shown that a Universal Turing Machine can be created within the rules of the game of life. That is, a computer which can compute game of life steps could, in theory, use this process to compute just about anything!
Here are another few patterns you might try embedding in a game board, to see what will happen.
diehard = [[0, 0, 0, 0, 0, 0, 1, 0], [1, 1, 0, 0, 0, 0, 0, 0], [0, 1, 0, 0, 0, 1, 1, 1]] boat = [[1, 1, 0], [1, 0, 1], [0, 1, 0]] r_pentomino = [[0, 1, 1], [1, 1, 0], [0, 1, 0]] beacon = [[0, 0, 1, 1], [0, 0, 1, 1], [1, 1, 0, 0], [1, 1, 0, 0]] acorn = [[0, 1, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [1, 1, 0, 0, 1, 1, 1]] spaceship = [[0, 0, 1, 1, 0], [1, 1, 0, 1, 1], [1, 1, 1, 1, 0], [0, 1, 1, 0, 0]] block_switch_engine = [[0, 0, 0, 0, 0, 0, 1, 0], [0, 0, 0, 0, 1, 0, 1, 1], [0, 0, 0, 0, 1, 0, 1, 0], [0, 0, 0, 0, 1, 0, 0, 0], [0, 0, 1, 0, 0, 0, 0, 0], [1, 0, 1, 0, 0, 0, 0, 0]]
I hope you enjoyed this quick exploration! For more information on the wealth of information about this game, you can browse the discussions and forums at Conway's Game of Life
This post was written in an IPython notebook, which can be downloaded here, or viewed statically here. | http://jakevdp.github.io/blog/2013/08/07/conways-game-of-life/ | CC-MAIN-2018-39 | refinedweb | 1,473 | 57.61 |
Given that COVID-19 is showing no signs of slowing down in many regions of the world, it’s more important than ever to maintain “social distancing” aka physical distancing between persons not of the same household in both indoor and outdoor settings. Several national health agencies including the Center for Disease Control (CDC) have recognized that the virus can be spread if “an infected person coughs, sneezes, or talks, and droplets from their mouth or nose are launched into the air and land in the mouths or noses of people nearby.”
To minimize the likelihood of coming in contact with these droplets, it is recommended that any two persons should maintain a physical distance of 1.8 meters apart (approximately 6 feet). Different governing bodies have different rules for safe social distancing and different penalties for breaking them.
We don’t advocate putting in place surveillance to enforce social distancing. Rather, as an interesting exercise, we will use the fact that machine learning and object detection have come a long way in being able to recognize objects in an image. Let’s understand how Python can be used to monitor social distancing.
Python can be used to detect people’s faces in a photo or video loop, and then estimate their distance from each other. While the method we’ll use is not the most accurate, it’s cheap, fast and good enough to learn something about the efficacy of computer vision when it comes to social distancing. Also, this approach is simple enough to be extended to an android compatible solution, so it can be used in the field.
Social Distancing, Python, And Trigonometry
Let’s start by outlining the process to address our use case:
- Pre-Process images taken by a video camera to detect the contours of the components of the images (using Python)
- Classify each contour as a face or not (also using Python)
- Approximate the distance between faces detected by the camera (do you remember your trigonometry?)
To accomplish the Python parts, we’ll use the OpenCV library, which implements most of the state-of-the-art algorithms for computer vision. It’s written in C++ but has bindings for both Python and Java. It also has an Android SDK that could help extend the solution for mobile devices. Such a mobile application might be particularly useful for live, on demand assessments of social distancing using Python.
Steps 1 and 2 in our process are fairly straightforward because OpenCV provides methods to get results in a single line of code. The following code creates a function faces_dist, which takes care of detecting all the faces in an image:
def faces_dist(classifier, ref_width, ref_pix): ratio_px_cm = ref_width / ref_pix cap = cv2.VideoCapture(0) while True: _, img = cap.read() gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # detect all the faces on the image faces = classifier.detectMultiScale( gray, 1.1, 4) annotate_faces( img, faces, ratio_px_cm) k = cv2.waitKey(30) & 0xff # use ESC to terminate if k==27: break # release the camera cap.release()
After starting the camera in video mode, we enter into an infinite loop to process each image streamed from the video. To simplify identification, the routine transforms the image to grayscale, and then, using the classifier passed as an argument, we get a list of tuples that contains the X, Y coordinates for each face detected along with the corresponding Width and Height which gives us a rectangle.
Next, we call the annotate_faces function, which is in charge of drawing the detected rectangles and calculating the euclidean distance between the objects detected:
def annotate_faces( img, faces, ratio_px_cm ): points = [] for (x, y, w, h) in faces: center = (x+(int(w/2)), y+(int(h/2))) cv2.circle( img, center, 2, (0,255,0),2) for p in points: ed = euclidean_dist( p, center ) * ratio_px_cm color = (0,255,0) if ed < MIN_DIST: color = (0,0,255) # draw a rectangle over each detected face cv2.rectangle( img, (x, y), (x+w, y+h), color, 2) # put the distance as text over the face's rectangle cv2.putText( img, "%scm" % (ed), (x, h -10), cv2.FONT_HERSHEY_SIMPLEX, 0.5, color, 2) # draw a line between the faces detected cv2.line( img, center, p, color, 5) points.append( center ) cv2.imshow('img', img )
Object Detection Using Python
Now that we’re well on our way to solving the problem, let’s step back and review Python’s object detection capabilities in general, and human face detection in particular. We’re using a classifier to do human face detection. In the simplest sense, a classifier can be thought of as a function that chooses a category for a given object. In our case, the classifier is provided by the OpenCV library (of course, you could write your own classifier, but that’s a subject for another time). OpenCV has already been pre-trained against an extensive dataset of images featuring human faces. As a result, it can be very reliable in detecting areas of an image that correspond to human faces. But because real world use cases can differ, OpenCV provides two models for detection:
- Local Binary Pattern (LBP) divides the image into small quadrants (3×3 pixels) and checks if the quadrants surrounding the center are darker or not. If they are, it assigns them to 1; if not 0. Given this information, the algorithm checks a feature vector against the pre-trained ones and returns if an area is a face or not. This classifier is fast, but prone to error with higher false positives.
- Haar Classifier is based on the features in adjacent rectangular sections of the image whose intensities are computed and compared. The Haar-like classifier is slower than LBP, but typically far more accurate.
Our use case for object detection is quite specific since it pertains to social distancing: we need to detect faces, which both classifiers are suited for. But we also need to build an area that represents the most prominent part of the face. That’s because in order to calculate the distance between faces, we first need to approximate the distance the faces are from the camera, which will be based on a comparison of the widths of the facial areas detected.
As a result, we have chosen the Haar Classifier since in our tests the rectangle detected for the face was better than that approximated by LBP.
Approximating Distances
Now that we can reliably detect the faces in each image, it’s time to tackle step 3: calculating the distance between the faces. That is, to approximate the distance between the centroid of each rectangle drawn. To accomplish that, we have to calculate the ratio between pixels and cm measured from a known distance for a known object reference. The reference_pixels function calculates this value which is used in the faces_dist function described earlier:
def reference_pixels(image_path, ref_distance, ref_width): # open reference image image = cv2.imread( image_path ) edged = get_edged( image ) # detect all contours over the gray image allContours = cv2.findContours( edged.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE ) allContours = imutils.grab_contours( allContours ) markerContour = get_marker( allContours ) # use the marker width to calculate the focal length of the camera pixels = (cv2.minAreaRect( markerContour ))[1][0] return pixels
We can use the classic Euclidean distance formula between each centroid, and then transform it to measurement units (cm) using the ratio calculated:
D = square_root( (point1_x + point2_x ) ^2 + (point1_y + point2_y ) ^2 )
With this simple formula our annotate_faces function adds the approximation to a line drawn from each centroid. If the approximation is lower than the minimal distance required the line will be red.
Object Detection Programmed For Social Distancing
The complete source code for this example is available in my Github repository. There, you’ll find the code in which we pass three arguments to our Python script:
- The path of the reference image
- The reference distance in centimeters
- The reference width in centimeters
Given these parameters, our code will calculate the focal length of the camera, and then use detect_faces.py to determine the approximate distances between the faces the camera detects. To stop the infinite cycle, just press the ESC key. The GitHub repo also contains reference images and two datasets for OpenCV’s classifiers.
classifier = cv2.CascadeClassifier('haarcascade_frontalface_default.xml') #classifier = cv2.CascadeClassifier('lbpcascade_frontalface_improved.xml') IMG_SRC = sys.argv[1] REF_DISTANCE = float(sys.argv[2]) REF_WIDTH = float(sys.argv[3]) FL = largest_marker_focal_len( IMG_SRC, REF_DISTANCE, REF_WIDTH ) faces_dist(classifier, REF_WIDTH, REF_WIDTH, FL)
To try out the code, start by downloading the Social Distancing runtime environment, which contains a recent version of Python and all the packages you need to run my code, including OpenCV.
NOTE: the simplest way to install the environment is to first install the ActiveState Platform’s command line interface (CLI), the State Tool.
If you’re on Windows, you can use Powershell to install the State Tool:
IEX(New-Object Net.WebClient).downloadString('')
If you’re on Linux, run:
sh <(curl -q)
Now run the following to automatically create a virtual environment, and then download and install the Social Distancing runtime environment into it:
state activate Pizza-Team/Social-Distancing
To learn more about working with the State Tool, refer to the documentation.
Conclusions
Of course, this is not a production-ready way to ensure social distancing and keep you safe from close talkers. You can improve this solution using more accurate approaches to detect faces (as neural networks created either with OpenCV or Tensorflow), or else using more than a single camera (similar to how kinect works). But for our purposes of object detection, we have a working solution with relatively minimal effort. | https://sweetcode.io/how-to-monitor-social-distancing-using-python-and-object-detection/ | CC-MAIN-2021-21 | refinedweb | 1,596 | 50.97 |
Tips & Tricks of Deploying Deep Learning Webapp on Heroku Cloud
Learn model deployment issues and solutions on deploying a TensorFlow-based image classifier Streamlit app on a Heroku server.
Image by Author.
Heroku Cloud is famous among web developers and machine learning enthusiasts. The platform provides easy ways to deploy and maintain the web application, but if you are not familiar with deploying deep learning applications, you might struggle with storage and dependence issues. This guide will make your deployment process smoother so that you can focus on creating amazing web applications. We will be learning about DVC integration, Git & CLI-based deployment, error code H10, playing around with Python packages, and optimizing storage.
Git & CLI-based Deployment
The Streamlit app can be deployed with git, GitHub integration, or using Docker. The git-based approach is by far a faster and easier way to deploy any data app on Heroku server.
Simple Git-based
The Streamlit app can be deployed using:
git remote add heroku:[email protected]/.git git push -f heroku HEAD:master
For this to work, you need:
- Heroku API Key
- Heroku App: either by CLI or using the website.
- Git-based project
- Procfile
CLI-based
CLI-based deployment is basic and easy to learn.
Image by Author.
- Create a free Heroku account here.
- Install Heroku CLI using this link.
- Either clone remote repository or use git init
- Type heroku login and heroku create dagshub-pc-app. This will log you into the server and create an app on a web server.
- Now create Procfile containing the commands to run the app: web: streamlit run --server.port $PORT streamlit_app.py
- Finally, commit and push code to heroku server git push heroku master
PORT
If you are running the app with streamlit run app.py it will produce an error code H10 which means $PORT assigned by the server was not used by the Streamlit app.
You need to:
- Set PORT by using Heroku CLI
heroku config:set PORT=8080
- Make changes in your Procfile and add server port in arguments.
web: streamlit run --server.port $PORT app.py
Tweaking Python Packages
This part took me 2 days to debug as Heroku cloud comes with a 500MB limitation, and the new TensorFlow package is 489.6MB. To avoid dependencies and storage issues, we need to make changes in the requirements.txt file:
- Add tensorflow-cpu instead of tensorflow which will reduce our slug size from 765MB to 400MB.
- Add opencv-python-headless instead of opencv-python to avoid installing external dependencies. This will resolve all the cv2 errors.
- Remove all unnecessary packages except numpy, Pillow, andstreamlit.
DVC Integration
Image by Author.
There are a few steps required for successfully pulling data from the DVC server.
- First, we will install a buildpack that will allow the installation of apt-files by using Heroku API
heroku buildpacks:add --index 1 heroku-community/apt
- Create a file name Aptfile and add the latest DVC version
- In your app.py file add extra lines of code:
import os if "DYNO" in os.environ and os.path.isdir(".dvc"): os.system("dvc config core.no_scm true") if os.system(f"dvc pull") != 0: exit("dvc pull failed") os.system("rm -r .dvc .apt/usr/lib/dvc")
After that, commit and push your code to Heroku server. Upon successful deployment, the app will automatically pull the data from DVC server.
Optimizing Storage
There are multiple ways to optimize storage, and the most common is to use Docker. By using the docker method, you can bypass the 500MB limit, and you also have the freedom to install any third-party integration or packages. To learn more about how to use docker, check out this guide.
For optimizing storage:
- Only add model inference python libraries in requiremnets.txt
- We can pull selective data from DVC by using
dvc pull {model} {sample_data1} {sample_data2}..
- We only need a model inference file, so add the rest of the files to .slugignore, which works similarly to .gitignore. To learn more, check out Slug Compiler.
- Remove .dvc and .apt/usr/lib/dvc directories after successfully pulling the data from the server.
Outcomes
The initial slug size was 850MB, but with storage and package optimizations, the final slug size was reduced to 400MB. We have solved error code H10 with a simple command and added opencv-python-headless package to solve dependency issues. This guide was created to overcome some of the common problems faced by beginners on Heroku servers.
The Docker-based deployment can solve a lot of storage problems, but it comes with complexity and a slow deployment process. You can use heroku container:push web, but before that, you need to build the docker, test it, and resolve all the issues locally before you can push it. This method is preferred by advanced Heroku users.
The next challenge is to deploy your web application with webhook. This will allow us to automate the entire machine learning ecosystem from any platform. The automation process will involve creating a simple Flask web server that will run shell commands.
Additional Resources | https://www.kdnuggets.com/2021/12/tips-tricks-deploying-dl-webapps-heroku.html | CC-MAIN-2022-05 | refinedweb | 848 | 65.83 |
IBM Announcements on Chip Design/Nanocommunications 111
mr was one of the folks who wrote about some IBM scientists who have discovered a way to transport information on the atomic scale that uses the wave nature of electrons instead of conventional wiring. The new phenomenon, called the "quantum mirage" effect, may enable data transfer within future nanoscale electronic circuits too small to use wires. Big Blue also unveiled some new chip technology, called "Interlocked Pipelined CMOS" that starts at 1 GHz, and will be able to deliver between 3.3 - 4.5 Ghz.
"Interlocked Pipelined CMOS" (Score:1)
Advantages of 128 bit word length (Score:1)
For the small portion of the population who don't regularly calculate cross products of 7-D vectors, the main advantage is that "128 bit computer" sounds better than "64 bit computer".
Re:(OT)Where are the damned DeCSS Source T-Shirts? (Score:1)
eBay has a whole section for terminals. (Score:1)
- A.P.
--
"One World, one Web, one Program" - Microsoft promotional ad
Wanna know why? (Score:2)
ISO-9K is a great way to turn any company into a shithole.
- A.P.
--
"One World, one Web, one Program" - Microsoft promotional ad
Next revolution (Score:2)
Ethernet (Score:1)
Seriously though, all this new tech just plain rules. I can't wait to see what things are like when I'm 90!
---
Don Rude - AKA - RudeDude
Re:Ready Set Go... (Score:1)
The guy you're flaming was complaining that the technology moves too fast for the user to keep up, or be able to safely upgrade. And I, for one, agree with him.
I tend to upgrade every two years or so, but if I upgraded componentwise, I'd want a motherboard that lasted.
And you made a lot of assumptions about that guy, alright? Think about it. If I had a few computers lying around (I do), and I bought a new one, I might want to build a better second one out of the remaining components. I tend to reuse old hard drives, because there are standards that allow this. What about chips?
Regular pentium-style ZIFF sockets were standard for a long time. Now we have all kinds of weird proprietary cards, buses, RAM, whatever. I know enough not to mix random RAM, but the complexity has definitely gotten out of hand for all but the up-to-date hardware hacker, and that isn't me.
---
pb Reply or e-mail; don't vaguely moderate [152.7.41.11].
Re:Ready Set Go... (Score:1)
Actually, I haven't messed with it, I went from a P133 to a K6/300, and my next purchase will be... well, whatever has the best price/performance ratio in x86-land by mid-summer, probably. But like I said, hardware hacking has gotten complicated enough for me to stay out of it, because I haven't been keeping up.
It used to be, you didn't miss much by not keeping up, like I said. IDE and SCSI, ATAPI cdrom drives, floppy controllers, ISA and PCI, Serial and Paralell Ports... and now they have to mess it all up with a bunch of proprietary, non-standard technologies.
If there were an open spec, I know I wouldn't have to wait this long for decent support under Linux. But no, we've got incompatible video cards, incompatible processor extensions, incompatible media, incompatible I/O... Obviously there's an advantage to standardizing the hardware platforms and the software interfaces. I'd be happy with maybe two, well-documented, competing standards in each separate domain. But no...
---
pb Reply or e-mail; don't vaguely moderate [152.7.41.11].
Re:Wanna know why? (Score:2)
Hmmm... I tend to disagree. ISO-900x is just a means of proving you have documented all your processes. All it really does is show that the company is a shithole earlier on by pointing out through documentation where they are headed.
Six sigma... now <b>there</B> is a tedious thing to go through.
Re:Makes sense (Score:1)
I know this reply is too late to catch the moderators eye, but I hope Mr. Hard_Code at least notices it.
Most commodity CPUs (and many other chips) are actually pipelined. They do some amount of work on the first clock tick, and send the results to another part of the chip, next tick they do the same amount of work on the new data, and another part of the chip works on the results of the the last cycle. A "modern" x86 CPU does that 8 to 18 times to handle each instruction. There are other wrinkles to it too.
When you design a CPU (in my case a "play" CPU much like the really old PDP-8) you use software that does a layout and tells you the critical path (most any VHDL synt tool will do). That's the slowest part which forces the rest of the circut to be clocked slower. When you find it there are three choices:
I don't know if the 68000 was pipelined. The 68010 was, I think it had three pipe stages (and no cache, although the loop-mode was a lot like a 3 instruction I-cache). Some RISC CPUs have pretty long pipelines, but the moderen Intels tend to be longer, in part because decode takes as many as three pipe stages (it does on the K7, not sure if the PII/PIII does it in two or three). A RISC decode is only one pipe-stage, and frequently other crap is thrown in too (like branch prediciton forwarding logic). By way of contrast the IBM PowerAS (a PowerPC like CPU) has a very short pipeline, I think about 6 stages (and thanks to the branch forwarding logic, branch mis-predict penalitys are something like only 2 to 4 cycles).
P.S. I'm not a hardware guy. I'm a software guy, and a harware wannabe.
Re:"Interlocked PipelinedCMOS" (Score:2)
It's got to be more then that. The TI SuperSPARC did that in '95 or so. Most of the CPU ran at (I think) 50Mhz, but the register file at 100Mhz. In that case (and all similar cases I know of) all the clocks are multiples of each other (no relitavly prime clock rates).
More over if the decode unit runs faster then the dispatch unit there is no useful gain. The dispatch unit has to be fed decoded instructions. The same is true for many (but not all) other parts of the CPU.
I think (with no proof, and no help from that watered-down article) that most of the parts in this chip run at the same speed (say 1Ghz). They each have their own 1Ghz clock distribution net, and they are not sync'ed with each other (so the ALU could see start of clock while the decoder is half way through a clock, and the renamer has just seen the end of a clock pulse). The boundry between each clocked unit must have a small async buffer.
That would trade the pain of clock distribution for the pain of having a bunch of async buffering all over the place adding to latency. Given how painful clock distrubution is in really big chips this is probbably a positave tradeoff. At least for latency intolerent workloads.
Re:Electron waveguides. (Score:1)
WRT tunneling, you're correct that electrons spend a good deal of time in the "mirage" position - it's not a mirage at all, any more than any de Broglie wave is. For instance you could call the peak of the interference pattern in the classic two-slit experiment a "mirage" too since it has an high electron density.
The speed of the electrons between foci is definitely sub-light speed. The de Broglie waves themselves may travel FTL (the same old non-locality that gets everybody excited) but as in all of these situations it's not much use.
It seems to me if they used a pair of parabolic reflectors similar to microwave dishes, they could get current to flow between foci over relatively large distances, with no hardware needed in between (except for the copper substrate, which is already a conductor - oops). I believe that different beams could cross as well, with little interference. That would be a useful feature, since it could replace circuit traces. It's doubtful whether this arrangement would be very efficient, due to leakage, diffraction, etc., but it's though-provoking.
Re:A Question About IBM (Score:2)
OTOH, IBM has been noted for their research programs. About 20 yrs ago, there was the big three in terms of corporate research. They were AT&T, IBM, and Exxon. Well Exxon has greatly reduced their research efforts (as had the other major oil companies), AT&T has been split up and then again split up again (Bell Labs is part of Lucent), while IBM has redirected their researchers to perform more applied research. But IBM research is still very impressive. Low temperature super-conductivity was an IBM product that came out their Zurich research facility.
Off topic, but Thomas Watson many years ago had the now-famous Think posters put up. I used to have a cartoon in my office that showed the Think poster with a guy saying, "I'll like to, but I have too much work to do."
Ross Perot founded EDS (after being an IBM salesman) to provide software for IBM mainframes. Back then, IBM philosophy was to sell hardware, software was just an afterthought. Hmmm, I wonder if anybody else got rich for selling software that ran on IBM hardware.
Yup, I'm just rambling. IBM is a "friend" of linux at this moment. They have been very good for the time being. However, as a person who has witnessed the might of IBM in the past, I'm scared of what IBM could potentially do to screw things up. Remember, the enemy (linux) of my enemy (MS) is my friend. Of course, we all live by the ancient Chinese saying/curse, "May you live interesting times."
And it still will *just* be fast enough (Score:2)
Great.
w/clocks newer than w/o clocks (Score:1)
Re:Interesting... (Score:2)
My question is are the clocks phase locked to a master timing source or are they free running?
Re:Fast (Score:2)
Quite Exciting!! (Score:1)
Nothing like real innovation, is there?
It excits me to see technology like this being announced.-Brent
How does this help us make smaller circuits? (Score:1)
Someone help me make the intellectual leap so that I understand how this can be used to help us build better circuits. Is the idea that we replace wires with really long, eliptical corals?
Re:Fast (Score:1)
I'm running a Pentium Pro 233.. and it certainly doesn't *feel* outdated.
Now, if only I had a fast internet connection to match...
A Question About IBM (Score:3)
Is it just me, or has IBM made a real turnaround in the last 5+ years? It seems they understand the whole open source movement, they've pretty much ditched they're sorry aptivas, and they seem to be a leader in new technologies. On top of that they've changed the way people percieve them. I remember hearing stories about how they had to wear knee-high black socks to match their black suits long ago, and now I go to an interview with them, and the guy is wearing jeans and a Polo shirt!
Honestly, this is one large corporation I have respect for. And there aren't too many of those left now and days.
Re:How does this help us make smaller circuits? (Score:1)
Disclaimer: I got a C+ in physics
-B
Re:slashdot (Score:2)
Hmmmm...
1: It's the "obscure university" that Alan Turing was a professor at.
2: It's the "obscure university" that built the world's first stored-program computer (the Manchester Mark I/"Baby")
3: It's either very similar or identical technology.
4: They've built the chips. They have prototypes.
5: Funny how everyone jumps up and down in defence of IBM, when they quite happily quote unrelated tech after unrelated tech to prove that Microsoft doesn't innovate...
Simon
Re:Interesting... (Score:3)
It's even less conceptually brilliant, when you see what people elsewhere have been working on - namely wavepipelined architectures.
Funny... people just keep on reinventing the wheel... fire... and then they patent it to hell.
IIRC, the guys at Manchester University [man.ac.uk] were working on this back in 1989/1990 (or at least they were when I went on a tour of the place...). Back then, it was just called the "wave pipelined RISC chip" - these days, it's the "Amulet". Check it out. It's based on ye olde ARM [arm.com] processor architecture - but the implementation is completely asynchronous -- that is, each individual logic element is clocked separately.
Sure, it's still experimental... sure, it's slower than other chips - but it also predates IBM's announcement by about 11 years. Just goes to show - academia ain't entirely useless
Links
Architectural Overview at Berkeley [berkeley.edu]
The Amulet Asynchronous Logic Group at Manchester University [man.ac.uk]
Who needs clocks? Bah!
Simon
Err - quantum EFFECTS (Score:1)
#include "disclaim.h"
"All the best people in life seem to like LINUX." - Steve Wozniak
Quantum efrfects used to ENABLE nanotech (Score:2)
#include "disclaim.h"
"All the best people in life seem to like LINUX." - Steve Wozniak
Re:Fast (Score:1)
But for now, IBM.. stick to... (Score:1)
-----
Linux user: if (nt == unstable) { switchTo.linux() }
Interesting... (Score:3)
This was probably quite difficult to implement, but isn't exactly conceptually brilliant. Modern computers already run at different clock rates internally. Your disk I/O bus runs at one speed, your video processor runs at another speed and the CPU still spends a lot of time waiting for stuff to come down the system bus from memory.
As far as I can see, IBM have scaled this down to a single chip, which will increase overall throughput considerably. Difficult to do, very worthwhile, but conceptually all they have done is to get the latency issues into a smaller space.
OTOH, this could lead to an architecture with considerably lower power consumtion, which is definitely worth doing.
The bit about 'quantum mirages' has already been discussed on
7-dimensional cross-product (WAY off-topic) (Score:1)
Remember how to get the cross-product manually? You make a matrix like this:
| i. j. k. |
| x1 y1 z1 |
| x2 y2 z2 |
...and take the determinant. To get a similar matrix with 7-dimensional vectors, you'd need six of them.
But I don't know how much use that would be.
--
Patrick Doyle
That doesn't make any sense (Score:1)
What do you mean by a transaction? And what does word size have to do with how many of them you can do per second?
--
Patrick Doyle
Doubling word size is not necessarily best (Score:1)
However, 64-bit is definitely worthwhile over 32-bit because 32 bits can only address 4GB. Under Linux, for instance, you only get 3GB of those because the last GB is reserved for the system. This places a hard limit on the size of things you can map into your address space.
64 bits can address 16EB (that's Exabytes), which should stave off Moore's law for another 50 years or so.
--
Patrick Doyle
When... (Score:1)
I suspect scientists are working on it. 'Cause eventually, we're going to have to start using quantuum states and tweeking the fundamental nature of the universe to build processors fast enough keep up with the computational requirements of Windows 2020...
Re:Makes sense (Score:1)
With multiple clocks, everything is working asynchronously at the limit of its own circuit. For simple circuits this will be very fast.
Jazilla.org - the Java Mozilla [sourceforge.net]
Makes sense (Score:2)
Jazilla.org - the Java Mozilla [sourceforge.net]
Re:Wanna know why? (Score:1)
Hmmm... you know, maybe that's what the Justice Department could do to penalize Microsoft. Require them to implement the Six Sigma program there, and get all their products compliant. Considering the current state of their software, it would either destroy them when they couldn't do it, or at least slow and bog their releases so much that other companies can somewhat catch up.
As it is now, they're, what, point-six sigma?
---
Re:Ready Set Go... (Score:1)
That's ridiculous. Why do you want the fastest CPU on the market? Why do you honestly need it? What's that? You don't need it? You just want to brag to your other 13 year old friends that your computer is faster than theirs? Oh, tough luck to you. Other people, people who are trying to get REAL WORK DONE, are actually happy that technology is moving quickly. Maybe if you can't handle it, you should go buy a Apple Macintosh. I hear they don't innovate very often. You can have a top-of-the-line computer for years and years.
Geez... I have a dual cpu Pentium III 450 MHz system, and according to my research, there isn't anything out there much more than 50% faster than it (say, a 733 MHz Coppermine in an i820 motherboard). When dual and quad CPU Coppermine systems become available, I *might* upgrade to one of those. If I *need* the speed increase, that is. Why upgrade when all I could get is a 50% speed increase, though? It'd cost me hundreds of dollars.
All you need to do is buy a decent computer (Dual or quad CPUs, Ultra2 SCSI, Asus motherboard), and you'll be set for *years*. No need to upgrade every month. It might cost more in the short run, but it'll last a hell of a lot longer than that Celeron/EIDE based computer you bought for $100.
Re:Fast (Score:1)
I'd rather see a 64 bit, 66 MHz PCI bus in consumer motherboards. There are increasingly more peripherals that exceed the bandwidth of the 32 bit, 33 MHz PCI bus. And they're getting cheaper every week. Adaptec Ultra 160 SCSI adapters are only ~$250. I'd buy one if I could actually handle the bandwidth...
Re:Ready Set Go... (Score:1)
Oh, come on. It's not that hard to keep up to date with new stuff. Slot 1 CPUs go in... slot 1! Slot 1 has been around for years now. Do you know why Socket 7 was around for so long? Because AMD used it for so long. Intel abandoned it a loooong time ago for their proprietary Slot 1 architecture. AMD couldn't make Slot 1 CPUs. But all you needed to do was buy any old Slot 1 CPU (from 233 MHz to 600 MHz), and it would work in virtually any Slot 1 motherboard. Is that so bad? No, it is not. Which Slot 1 CPUs don't work in Slot 1 motherboards? The new Coppermine CPUs, if you're unlucky. The Coppermind CPUs will work in many (but not all) Slot 1 motherboards! For years now, you could have used the same Slot 1 motherboard, just upgrading CPUs. What are you complaining about? That your 486 doesn't work in a Pentium II motherboard? Oh well.... time goes on.
Re:A Question About IBM (Score:2)
Electron waveguides. (Score:2)
I wonder if the "mirage" could be interpreted as the electrons of the cobalt atom tunneling to the image location and spending a fraction of their time there? That less-than-half strength might be because the nucleus is still at the other location and makes the electron density "prefer" that region because it is lower energy, due to the attraction of the positive charge.
I also wonder what is the speed of propagation of the effect? Switch a gate's output by dropping an electon into an electron trap at one end of the waveguide, and it appears (at, say, 50% density) at the other end, and affects the logic there. How long does it take to happen? Does it exceed the speed of signals in a wire? (That's a very small fraction of lightspeed on a chip, where the wire resistance and stray capacatance form a delay line.) Does it approach that of light in vacuum? Does it EXCEED that of light in vacuum? (Even if the total system can't send signals faster than light in emptyness, which is a very slight improvement on light in quantum vacuum.)
Whatever it is, my bet is that it will happen at tunneling speed.
Re:School computers (Score:1)
but the apple II e's that were in my highschool's computer lab might not be state of the are anymore
Re:Fast (Score:1)
Perhaps I'm not seeing something, but I can think of very few situations in which 128-bits is a definite advantage over 64.
Bits != total computational power, people.
Re:Slashdot has it (Score:1)
appears again... but perhaps what is scarier is:
slashdot + (anti)slashdot -> geocities +14.3 KeV
Here's another.... (Score:1)
---
But.. (Score:1)
---
Re:i think this is bigger than its made out to be (Score:2)
I'd much rather have a cluster of P3 or Athlons.
Re:Fast (Score:2)
Maybe if AMD... (Score:1)
Sigh.
Esperandi
Re:Ready Set Go... (Score:1)
-lol- You obviously haven't been keeping up with the news. Apple's G4s are among the fastest things out there.
Kean
some more references: (Score:3)
Ok the reference for this work is:
H. C. Manoharan, C. P. Lutz & D. M. Eigler, Nature403, 512-515(2000).
In this experiment a few Cobalt atoms were deposited on a Copper surface. Using a scanning tunneling microscope the Co atoms were gently dragged into an elliptic(coral) structure, and one Co atom was placed at the focus of the ellipse. (The images of this stuff are gorgeous and more cool STM images of atoms and atomic maniputation can be found at the STM Image Gallery [ibm.com]).
Due to the magnetic nature of the Co atom electrons near the atom tend to align their spins with the Co magnetic field screening the magnetic moment. This local phenomina can be imaged by the STM, the surprising result is that another mirage image appears at the second focus of the ellipse. This suggests some sort of long range electon ordering.
These experiments are being done with a low temperature ultra-high vacuum stm (this stuff is damn hard) and to reproduce these same results in a next generation processor as a means to transport data is unlikely in the near future. Nevertheless, these results will have a great effect in our understanding of macroscopic quantum systems and ordering.
Re:Ready Set Go... (Score:1)
Re:Fast (Score:1)
Slashdot has it (Score:4)
Re:(OT)Where are the damned DeCSS Source T-Shirts? (Score:1)
Nick Messick
nick@trendwhore.com
Re:How does this help us make smaller circuits? (Score:1)
Re:Is this actually a Big Deal(tm) (Score:1)
slashdot (Score:1)
If you will excuse me, I have a computer lab to attend to.
Fast (Score:2)
This stuff is kinda of cool though, maybe we'll get to see some nice VR stuff and better speech recognition. Eventually the hardware will be fast enough to run windows.
I would have liked to have seen intel go to a 128 bit architecture instead of 64 it would have lasted longer.
Re:Interesting... (Score:1)
ex-employee btw
Re:Quantum efrfects used to ENABLE nanotech (Score:1)
The IBM engineers are really ENGINEERS. They are thinking about solutions and how to address the problem *using* the boundaries that nature has given us rather than attempting to find ways around them.
also I didn't realise that K.E.D. did physics as well as write books. you'd get a moderation if I hadn't already posted to this story.
Re:slashdot (Score:1)
btw presumably you are at Umist/manchester. Top place.
Re:A Question About IBM (Score:2)
all he did was make the technology and engineers they always had the focus
Re:School computers (Score:1)
Let me know if they plan on getting rid of them... I'm looking for a couple of text terminals to hook up to my linux box.
I'm looking for something that can emulate a DEC vt100... but I can't find any in my area (north Jersey).
q
Re:eBay has a whole section for terminals. (Score:1)
q
Asynchronous processors (Score:1)
(Place where the first computer was built 51 years ago)
Really cool stuff
Amulet Processors [man.ac.uk]
Re:Asynchronous processors (Score:1)
at approximately the same time as me.
The
Re:Asynchronous processors (Score:1)
Also the work is still continuing with other students and lecturers. Just because some of the original peole left doesn't mean the work will stop.
Quantum mirage story, again? (Score:1)
Re:Fast (Score:1)
64-bit numbers in parallel, or perhaps
4 32-bit numbers
Where have you been, altivec does just that (at least for the 4x32bit stuff).
Re:Fast (Score:1)
It has always been the case that once the computer's competency is there, the applications arrive... Way back in the mid-60's my father took me to an open house at IBM, and proudly demonstrated that the computer could add 2+2 lightning-fast. I asked why that was necessary, since I could do the same thing (ok, I was young once, too!)....
If you want to know what the new processors will be used for (in series, no less!), keep up with math! Learn about the complexities of modeling visual information (animation on a G4!), exploring "chaotic" (or "complex") domains, etc.
It's the new stuff we'll be able to DO that make new processors (and etc.) so exciting!
Re:Advantages of 128 bit word length (Score:1)
However, cross products of 2 vectors are only defined on 3 dimensions, how can you uniquely have something perpendicular to 2 vectors in 7 dimensions?!!
Re:If my computer... (Score:1)
Not only that, if it crashes and you lose data, can you go into the other universe and get the data back? If so, how do you get into the other universe to do so
;-)
Re:Is this actually a Big Deal(tm) (Score:1)
<sigh> Look, Moore's law is an observed phenomenon, not a fundamental rule, and it is observed in the industry as a whole, not necessarily within individual companies. If Intel doesn't come up with technologies allowing them ot go to 3.2 GHz within 3 years, then no, they won't have a 3.2 GHz then. It's by no means inevitable that they will come up with such technologies.
Here's a thought on this 'multi-clock' CPU of IBM's: What clock will they advertise it at? Presumably the clock of the fastest part. Still - maybe, just maybe, we'll start seeing marketing move away from clock speed as a meaningful measurement of chip performance. We can always hope.
Is this actually a Big Deal(tm) (Score:1)
Re:Is this actually a Big Deal(tm) (Score:1)
800 * 2 = 1600 in 18 months, then 1600 * 2 = 3200 in another 18 months. 18 + 18 = 36 = 3 years.
Re:Is this actually a Big Deal(tm) (Score:1)
Re:A Question About IBM (Score:2)
On the other hand, they still are a giant business. They do flexibility and open source because they think flexibility and open source work-- it's a business model and not a philosophy. Companies this big don't have philosophies, no matter how many True Believers they have on staff.
Re: Flaimbait? I think not. (Score:1)
If my computer... (Score:3)
I can see the error messages for Win2010 now:
"Error - user32.exe performed an illegal operation in this universe - please continue in another universe or restart..."
smarter than me (Score:1)
Big Blue? (Score:1) [badassmofo.com]
Re: Flaimbait? I think not. (Score:1) [badassmofo.com]
Re:Ready Set Go... (Score:1)
Behold the power of ONE
Re:School computers (Score:1)
Ready Set Go... (Score:2)
School computers (Score:3)
i think this is bigger than its made out to be (Score:1)
Re:How does this help us make smaller circuits? (Score:1) | https://slashdot.org/story/00/02/06/2052259/ibm-announcements-on-chip-designnanocommunications | CC-MAIN-2017-22 | refinedweb | 4,810 | 73.58 |
Ink AniEd is an animation tool based around Microsoft’s Ink architecture. The goal is to create an animation tool which is easy and intuitive to use, and allows the user to quickly create animations which can be used for any number of tasks, from prototyping moving GUIs, to storyboarding for movies, to creating your own cartoons. It was developed both as a standalone animation tool, and as a Windows Control that can be easily integrated into any application using the .NET Framework. And while AniEd was designed for the Tablet PC, and contains certain features only available on the Tablet PC, it will run with little noticeable difference on almost any computer with the .Net Framework.
In it’s standalone form, AniEd is a revolutionary step in animation, allowing for the greatest amount of quality animation, based on a small amount of user input. Specifically designed for the Tablet PC AniEd’s user interface makes bringing your Ink drawings to life as easy as cut and paste. All the normal Inking features which you know and love, are fully available to be applied to any single frame of animation. This means you can copy and paste frames to and from other documents allowing you to make animations as easily as you can think them.
As a component for other .Net applications, AniEd can be used as any other Control, and uses a few simple functions to manage it (like Play, Pause and the Time and UseEditor properties, which make creating your own animation editor or player a piece of cake). Also, the AniEd control gives you access to an Ink object which represents the current frame being viewed, this allows you to perform any normal Inking operation just as you would on any other Ink object. Using the AniEd control is recommended because it simplifies almost all operations to one or two simple function calls, however the architecture also allows you to make your own animation controls using a series of structures similar to the Ink class diagram. For instance you have StrokePath (to represent a Stroke through time), and InkPath (which represents a set of Strokes though time).
Play
Pause
Time
UseEditor
First of all, AniEd has been designed to be easy to use, and if you just follow these simple examples you’ll be up and animating in no time:
Okay, when you first start you should see a blank page. Draw a single line on it using your pen tip or left mouse button. Now that we’ve got a line, try dragging the “time bar” at the bottom of the screen until it says “Time = 2”. This means that you’ve gone ahead in time to 2 seconds from the first drawing. Now click the line you drew before, you’ll notice that a yellow border is drawn around it. Now draw another squiggly line, and you’ll notice it replaces the one you highlighted. Now hit the Stop button ( [] ), this sets you back to Time = 0. Now hit the Play button ( > ), and you’ll see your first stroke blend into your second stroke. Quickly press the Pause ( | | ) or Stop button to stop the animation from going on for ever.
What happened here was that you drew what your animation looked like at Time = 0, and what it looked like at Time = 2, then when you hit Play, the program went from 0 to 2 and worked out what it imagines the line would look like in between. You’ll find that it’s generally pretty good at guessing. These drawings are commonly known as “key frames” to animators, and are the basis for most animation techniques.
You can also change the color or width of any stroke, and the system will automatically fade between colours and width as it’s playing.
A little more useful task: Set the time to 0 using the “time bar”, and then draw a stick figure (so a head, a body, legs, arms etc.). Now set the “time bar” to some time ahead of 0, let’s say 4 seconds. Now click on the first part of the stick figure that you drew, and draw it again somewhere else. You will notice that once you’ve drawn the new position, the next part of the stick figure that you drew will automatically be selected. This means you can then also draw that part in it’s new position. In this way, you see how as long as you are doing drawings in a specific order (which most people do anyway), you can easily update a sketch to a new time and place, and make a cool looking animation.
Keep in mind, that you can also move the “time bar” to between two sketches, and redraw the sketch there as well, there really are no limitations on this. If you draw a sketch at any time, it will only appear at or after that time. So if you draw a sketch at 4 seconds, you will only see it after the 4th second of animation (you can also make sketches stop at a certain time, as will be discussed later).
You can also move, and modify sketches. To do this, first select them, which means draw a loop around them using either the “barrel switch” on your pen, or the right mouse button on your mouse. Just hold down that button, and draw a sort of outline of the strokes you wish to selected (this is known as the lasso). Once you’ve selected the strokes, you can drag them around, and perform all sorts of operations on them which you can find in a pop-up menu which you get by either right clicking on them, or taping them with your pen while holding down the barrel button.
There are of course a lot of other things you can do with AniEd other than what’s above, but with what you know now, you can easily work the other things out and have alot of fun doing it. Just keep in mind a few of the terms defined below and you should have no problem, Enjoy!
AniEd was developed on a Tablet PC (which I kindly lent to by the <place><placetype>University of <placename>Florida and Microsoft), and is really meant for Tablets. While it is possible to draw using the mouse, and some people do, many people (including myself) simply can’t stand it. What little artistic skill I do have it practically thrown away by the mouse. The Tablet is quite simply a superior input mechanism, and I believe that AniEd only makes this even more clear than it already was. Just try drawing a few frames and animating them using a Tablet, and then try with a mouse (or be like one of my crazy friends and try it with a touchpad) you will no doubt be convinced as to which is easier to use.
What we must realize is that the Tablet PC makes for us a new metaphor for input purely based on it’s ease. As we see in AniEd, the ability to quickly and easily create drawings is a tool we must not ignore. In the future, more applications will lean more toward dynamic content creation, rather than content manipulation. Consider that most animation systems such as those used for modern cartoons and computer games are based on an initial model being made and then doll style rotated and shifted into the goal position. With the Tablet PC we begin to see an environment when it is easier to make original drawings rather than mutate and manhandle previously existing ones. This I believe will be a major step forward in the evolution of time based user interactions.
This section and below are intended to give a technical overview of AniEd, and are by no means necessary for the average person to use AniEd. It’s intended audience are developers interested in AniEd, animation, Microsoft Ink, user interfaces, .Net, etc.
First of all, AniEd is designed to compliment and extend the Ink API, not to replace it. Internally, the architecture of AniEd is similar to the Ink API, and tries to use it whenever possible. With this I hope to gain from all the time and effort put into the Ink API, automatic integration into future advancements of the API, and also to make integration into future and existing applications as easy as possible. In a time when more and more APIs and standards are coming out, the last thing a developer needs is another one, in this way I hope you will see that the AniEd can be easily introduced into most applications, with little additional work, and you still keep and use all of your Ink based utilities.
AniEd itself is written entirely in C#, using Visual Studio .NET. This means that it is easy to compile down to a library and include in any .NETapplication. It does however require the Microsoft.Ink library which is on most, but not all .NETenabled PCs.
At it’s core the animation process is executed by interpolating between “key frame” strokes. The main difference between the standard Ink architecture and AniEd is obviously that standard Ink doesn’t contain any time based information. This along with numerous other differences make using standard Strokes a non-ideal choice for a animation. This is not to take anything away from the Ink API which I believe is a superb piece of work and does it’s job amazingly well, it just simply wasn’t designed to do animations. One of the main issues is the public accessibility of the data which make up each stroke without having to go through an intermediary like GetPoints. This allows for vastly improved look up speed which is exactly what is necessary for the interpolation used in animation. There are also a large number of other design changes, mostly based around the fact that standard Ink objects aren’t meant to be animated. However, repetition of code is avoided as much as possible, and where ever it was possible I exposed Ink conversion tools, and implemented features such as rendering and selection using modified version of the standard Ink API. The rendering is broken into a high performance renderer for animation playback, and a high quality renderer for normal viewing/editing (for the high performance renderer, the quality is adjustable, to give fine tuned control to the editing application). I use linear interpolation (i.e. only C0 continuity) because I found that it is more intuitive, and brings the giant goal of “pick up and use” much closer. C1 continuity of animation would have looked good in some cases, but would have made it a little more complicated to perform quick prototyping type work AniEd was designed for. Almost all of the system was designed for ease of use, from automatic selection of the next stroke to be drawn, to lasso selection, to an easy to understand animation metaphor.
GetPoints
Before Strokes are entered into AniEd, they are lengthwise resampled or reparameterized. This solves a major problem when using the Tablet PC pen for input, which generally creates a line with a large cluster of points all at one point along the line (i.e. whenever the user slowed down just a bit). This would make point based interpolation a nightmare and would cause it to cost way too much CPU time. My solution is to essentially move the control points around a little bit so that each point is an equal distance away from it’s two neighbors. While this causes a slight loss of quality in certain areas it is vastly made up by the time and quality of the resulting animations. Also due to the large amount of samplings from the pen, my early experimentation shows the loss of quality to be almost unnoticeable. Consider the diagram below:
*--*--*--*--*--*--*
*
/ \
*- -*- -*- -*
\ / \ /
* *
*
/ \
/ \
* * * *
\ / \ /
\ / \ /
* *
The input points are drawn as *s, and the lines drawn between the points are dashes or slashes. This gives you a rough idea of how how the input coordinates relate to the resulting line. The top most line is the initial line, the bottom most the final line, and the middle is the interpolant between the two.
Now see what happens when the input points for the initial line are not evenly spaced. Remember that the user cannot see the control points, but only the resulting line.
*-*-*-*-*-*-------*
*
/ \
* -* *- ----*
\ / \ /
* *
*
/ \
/ \
* * * *
\ / \ /
\ / \ /
* *
Notice now how the middle line is sort of bunch up onto the left side of the line, this is due entirely to uneven control point spacing, which is removed by the AniEd system.
Random access playback – Unlike certain over animation systems, AniEd can jump between rendering different times easily without really even noticing. This allows for features like backwards playing, slow-motion, fast replay all without almost any additional effort. The AniEd Control even includes a RateOfTime property which can be set to any positive or negative number to adjust how the animation is viewed.
RateOfTime
Interpolation Architecture – The interpolation subsystem used by AniEd is available to your application as well, which gives you utilities like interpolating betweens colors, ints, floats and such, and more advanced tools such as interpolating between point based lines, resampling an array to a different length, floating point indexing (from 0.0 to 1.0 instead of integer based), and length wise resampling of point based lines.
Stores pressure information – only available on the Tablet PC of course, the AniEd architecture is designed to store, interpolate, etc. pen normal pressure information along with the points and other information making up a Stroke. While the current Ink API doesn’t allow new Strokes to be created with user defined packet information (including pressure), the AniEd architecture is silently keeping all this information so that when hopefully newer versions of the API are released the changes which need to made to AniEd should take no time at all. Also, all previous animation files, which had pressure information, will finally be able to use it. Most of the Ink developer community (including myself) are waiting patiently for this addition.
Cut and Paste operations, using the clipboard are integrated into AniEd, so that any single frame or collection of strokes can be copied out of an animation and pasted into a document. Or ink object from other applications can be pasted as into AniEd, and then managed like any other Ink. The majority of cut and paste operations are based around the default Ink cut and paste methods, and thus will automatically update themselves as new versions and new formats arise.
Serialization is fully supported in that the InkPath object is serializable, and also exposed a custom set of save/load functions which offer a slight performance boost over the serialization method, and write into standard StreamWriter and StreamReader objects so that they can be made a part of a large file format. They also use a text based format, which compressed very well.
InkPath
StreamWriter
StreamReader
Low-memory usage: It uses a more direct access to information philosophy than the Microsoft Ink classes, for instance giving direct access to point buffers rather than first copying it into an intermediary buffer and then giving it to the requester. One of the distinct advantages here is that the dynamic memory usage during real-time playback is very minimal, and on the whole not a lot of memory is wasted or unnecessarily created and destroyed.
You can also use AniEd as an Ink collector (by just never adjusting the time) and benefit from features like lasso selection, dragging, copy/paste, save/load, etc, which while they may not be too much of a hassle to code, are nice to have wrapped into one neat little bundle.
For anyone looking for examples on how to use many of the features in .Net and the Ink API, I think you’ll find AniEd a good source. I know a few of the other projects I’ve been working on included me copy and pasting a lot of code from AniEd. Any, for those interested, here is a short list of some of the more important operations which you can find somewhere or other in AniEd:
Double buffering, continuous updating, Ink collection, dynamic Ink rendering, rendering using Ink, serialization, saving/loading Ink, Ink events, lasso selection, hit testing, Ink manipulation and interpolation, working with multiple Ink objects, copy and pasting Ink, animation playing/editing, Stroke packet management (in Strokes and in the NewPackets event), dragging Ink, and of course a whole bunch of other little things.
NewPackets
The simplest way to do this, is to include the AniEd control into your application as you would any other Control. Once you’ve done this, you’ll notice a few key functions. First of all the “Ink” property returns to you a standard Microsoft Ink object which you can use as you would any normal Ink. Also, the UseEditor property can be used to turning the editing mode on and off. But most importantly is probably the Play and Pause functions, which do exactly as one would expect. A smart move would also be to make sure you adjust the RateOfTime variable before playing, the default value of 1.0 means normal playback. Other than those basics, you will find that using AniEd is a very hands off process, as it does most of the work for you. In fact, if you simply turn the editor on (UseEditor=true) and then never adjust the Time variable or hit Play(), you can easily use AniEd as a Ink collector with most of the work done for you already.
UseEditor=true
There are also a few events you can subscribe to, such as the time change event, which is useful for say updating a text label as to the time in the animation, or moving along a track-bar to match the time. And there is even a context menu event, which is how AniEd tells you that you should bring up a context menu. If you look at the source code for the example application, you see that most features you would want to perform are only a few short method calls away.
If your feeling a little more “hard core” and want to create your own animated Ink control or other such app, you will find that your knowledge of the Ink API will make moving to animated Ink very simple. The equivalent of a Stroke is a StrokePath, which is a Stroke across time. The InkPath is equivalent to an Ink object, except also across time, and the InkPathViewer is semi-equivalent to the Renderer object. The difference is that the InkPathViewer includes a built in “selection” system where you can specify which strokes are currently being selected. This is necessary as Strokes are destroyed and recreated each frame, which makes keeping track of them a task which is more easily handled by the renderer itself.
StrokePath
InkPathViewer
Renderer
Also, each StrokePath is made up of a collection of StrokeITs (Strokes In Time), which are really the direct equivalent of Strokes, just with slightly looser access privileges (for faster access), and some time based information.
StrokeIT
You will find the entire AniEd API fully and (fairly) clearly commented and explained. Also be sure to check out the example editor, which shows you how easy it is to integrate animated Ink into your application. Oh, by the way, just because the AniEd example is non-resizable doesn’t mean that the AniEd control is, infact it doesn’t even notice when it’s resized, as it doesn’t affect it much. I was just going for that wide-screen movie editor look when creating the example app.
Included with the AniEd package you will get the executable, a few examples files, and the source code for AniEd.exe. This is of course just an example application of what can be done with AniEd, but it still quite a decent app in and of itself. If you look in the source directory you will find AniInk.cs, which contains the AniInk (animated Ink) namespace and everything is all in there, as a reference you can look at the example app and see how to use it. If you have any questions, feel free to contact me at lewey@ufl.edu . Of course I’m not liable for any damages that you may incur caused by your usage of anything in this package.
lewey@ufl.edu
One item I really should comment on is that this project was written basically in 6 days, and my prior knowledge of C#, .Net and the Ink API was sketchy at best before I began. The fact that I could pick up enough to make an animation editor out of it this quickly is a great compliment to it's simple and easy to use architecture.
One thing some people have asked for is sound effects, that would be cool, but it brings in a lot of headaches that I simply didn’t have time to deal with right now.
A Shockwave exporter would also be a nice addition, so that animations could be posted on the net for anyone.
And of course flat out more editing tools! Some of the most expensive software available is animation editing tools, there is no way I could complete with such people, the difference is just more coders creating more tools over more time (and being paid to do it), I believe the architecture I designed to be flexible enough to make the creation of such tools fairly easy, if someone just invested the time into it.
Thank you for you time, and I hope you enjoy AniEd. If you have any questions or comments I’d love to hear from you.
My webpage: The AniEd. | https://www.codeproject.com/Articles/4331/Ink-AniEd-An-Ink-Based-Animation-Editor | CC-MAIN-2022-05 | refinedweb | 3,652 | 55.58 |
I made a method that loads 2 strings from a text file, and adds them into an array, but it won't work, heres the code.
Thats the method, I make it print out the array, and it shows up Nothing Found, which means it didn't find what the value in the text file? Any help is greatly appreaciated.Thats the method, I make it print out the array, and it shows up Nothing Found, which means it didn't find what the value in the text file? Any help is greatly appreaciated."); } } }
This content has been marked as final. Show 5 replies
1. Re: Loading into String array?camickr May 31, 2009 2:03 AM (in response to 807588)The problem is with the code indenting. If the code isn't properly aligned you can't read it. And if you can't read the code then you can't see what the problem might be.
2. Re: Loading into String array?807588 May 31, 2009 2:08 AM (in response to 807588)I don't see what the problem is yet, but I don't have all the information I would want, either.
I don't know what's in the text file.
I don't know how you go about printing what's in the array.
Incidentally, you might consider moving the instantiation of the FileInputStream and Properties objects outside the loop, along with the loading of the properties object from the file. There's no need to do that multiple times, as near as I can tell, and moving it out makes it easier to figure out what you DO want to loop.
rc
3. Re: Loading into String array?807588 May 31, 2009 2:37 AM (in response to 807588)OK, whats in the text file is
test TESTING
4. Re: Loading into String array?807588 May 31, 2009 3:51 AM (in response to 807588)Whatever your problem is, you haven't described it completely.
Please excuse any typos in the following; my development environment and my internet are on different machines tonight,and I cannot copy-and-paste this over.
package rc.test; import java.io.*; import java.util.*; public class TestLP { static String[] toTest = new String[2]; public static void main (String[] arguments) { loadFile(); for (int i=0; i<toTest.length; i++) { System.out.println(toTest);
}
}");
}
}
}
}
With the file "myfile.txt" in the directory in which the program is run, and containing the single line "test TESTING", this program prints: TESTING TESTING All of your code is here, reformatted but otherwise intact; I've added what I surmised to be reasonable drivers to show us whether this code works as expected, and it does. Possibilities: The array you think you're loading the data into is in a different scope than the one loaded. You do not give us the declaration of that array, so we cannot tell. The printout of the information is somehow flawed. You don't show us how you output it, so we cannot tell. myfile.txt doesn't contain what you expect, or there is more than one copy. Perhaps "test" is capitalized, which would give the result you indicate. So would a file that doesn't actually contain "test" as a key. Part of the point here is that complete information would cost very little compared to what you've already done, and would allow us to help you better.
5. Re: Loading into String array?800308 May 31, 2009 4:08 AM (in response to 807588)
RCook wrote:Totally Agree.
Whatever your problem is, you haven't described it completely.
Here's my 2-bobs worth:
... Of course one has to ask "What's the point?" ... and if I saw this in a production codebase I be awfully tempted to refactor to eliminate it... but there you go... It is what it is, and it ain't what it ain't.
package forums; import java.io.FileInputStream; import java.io.IOException; import java.util.Properties; public class AutoLoadingProperties extends java.util.Properties { private static final long serialVersionUID = 1L; public AutoLoadingProperties(String filename) throws IOException { super.load( new FileInputStream(filename) ); } public static void main (String[] args) { try { Properties props = new AutoLoadingProperties("AutoLoadingProperties.properties"); props.list(System.out); } catch (Exception e) { e.printStackTrace(); } } }
Cheers. Keith. | https://community.oracle.com/thread/2052596?tstart=20640 | CC-MAIN-2017-22 | refinedweb | 719 | 75.3 |
Ogre Battle: The March of the Black Queen
FAQ/Walkthrough by NinjaJeff
Version: 1.0 | Updated: 09/01/04 | Printable Version | Search Guide | Bookmark Guide
"Ogre Battle" strategy guide/FAQ (for PSX and SNES) FAQ version 1.0 By Jeff Egley (feel free to email me at: jregley@students.wisc.edu) ***Ogre Battle Saga, Episode Five: "The March of the Black Queen"*** -Welcome to my FAQ! Listed within are the pointers and tips I can give you to getting through this VERY difficult, but yet VERY fun and VERY involving RPG/military strategy game. Use my table of contents to find a quick way to get to where you want to go if you are looking for something in particular. Enjoy! Table of Contents Prologue. Background Story I. Stage Bosses and how to defeat them II. Key and Definitions of Characteristics III. Character Class In-Depth Information IV. Quick Checklist to pursuing the Holy Path V. Imperial Specific Character Classes (ie, stuff you can't have!) VI. List of Special Characters (awesome people you can have join you!) VII. Alignment, Level Up, and Charisma Clarification VIII. The Encyclopedia of Magic and Special Attacks IX. Battle Tactics X. Tarot Card Encyclopedia XI. Rare Items and how to obtain them XII. Reputation Meter Clarification XIII. Hard-to-Find (but buyable) items, and their uses XIV. "All Star" Rankings (ie, best creatures and unit combos) XV. Cheats and Easter Eggs XVI. Ending Information XVII. Information about the Author XVIII. Disclaimer Information Prologue, the Background Story- -Many years ago, a decisive battle called the Ogre Battle was fought to decide who would rule the earth- Man, or Demon. Man received support from the Holy Gods and the Three Warriors, and the Demons and the Underworld received the support of the Evil Gods. Mankind won, but only just. Fierce fighting rampaged, and many a good person lost their life. The stories of the Ogre Battle became obscured by the mists of time, and became legend. Many years went by... A prosperous Kingdom was established by Prince Gran, the Sage Rashidi, the Monk Roshian, and the beastmaster Parcival, the four great disciples, who founded the three kingdoms, Horai, Ofays, and Zenobia, all humble and at peace. The monk Roshian went by himself and founded the Roshian religion, based at temples worldwide, which was a religion based on worshipping a good source of higher power, The Three Warriors, and the Holy Gods. Then, 25 years ago, a very fierce war was fought across the entire Zenobian continent. This war was caused by the Sage Rashidi, who, perhaps driven by madness and insanity, killed his friend, the Kind of the Zenobia, King Gran, and sided with Empress Endora, the queen of the Northern Highlands, which then invaded and waged warfare on the four other kingdoms: Ofays, Horai, Zenobia, and Sharom. The devastating surprise attack and the supremely overpowering military might of the highland warriors from the northern tundra only spent a year in total time defeating the four other kingdoms and wiping them from the face of the continent. The sole remaining kingdom, the victor, the Highlands, claimed entire control of the continent, and the Holy Zeteginean Empire, queened by Endora, and with Rashidi at her right hand, was born in the aftermath. The Empire's rule was a sheer reign of terror. Merciless politicians, city-state governors, and ruthless tax-collectors caused all of the citizens under their rule to suffer. Even freedom of speech and the press had been taken away. Many people were killed in the merciless corruption, and the people are desperately crying for help. The Empire has ruled for 24 years. But, yet, a ray of hope still glimmers. On the outskirts of Sharom, the last survivors of the Knights of Zenobia, the royal army of King Gran, are in hiding, awaiting their time to attack, and a new leader. This is where you come in... the reign of the Zeteginean Empire shall come to an end at your hand... or will it? Your actions will decide the story's outcome... Stage Bosses- Key- (Stage Number-Stage Name- Boss's Name) (Level and character class) (Amount of health) (Bodyguards accompanying the boss) (Which special character you should have confront this boss) (Destription) 1-CASTLE OF WARREN- Warren (***recruitable!***) Level 4 Wizard HP-108 Bodyguards- None -Warren the Wizard (nice name) is your very first fight in the game, and he should be very easy for you to defeat. Defeat him, and he and the rest of the troops that he has been sheltering will join you in your quest against the evil Zeteginean Empire. 2-SHAROM BORDER- Usar Level 5 Berzerker HP-120 Bodyguards- Two Level 4 Wizards Use against- Lans -Usar is an easily defeatable boss. He is fairly strong, but vulnerable to magic spells. He is also in the front row, so hitting him with physical attacks is just as easy. Moreover he is just practice against what is to come later in the game. 3-SHAROM DISTRICT- Gilbert (***recruitable!***) Level 6 Beast Tamer HP-120 Bodyguards- Two Level 6 Wyrms Use against- Canopus -Gilbert is the boss of Sharom, and if you defeat him by using Canopus (his best friend), he will see the error of his mistake and ask for your forgiveness. Forgive him and he will join you. 4-POGROM FOREST- Kapella Level 8 Mage HP-116 Bodyguards- Three Level 7 Imps Kapella is the first disciple of Sage Rashidi and Kapella is a VERY powerful magician, and is a challenging enemy commander for so early in the game. You will be shown how powerful a Mage is early on, as the spell he casts will hit your entire unit. He is very dangerous, so save a World card for him. World card yourself, and then Fool card his bodyguards. He will fold easily to any physical attack. 5-LAKE JANSENNIA- Sirius Level 7 Lycanthrope/Werewolf HP-112 Bodyguards- Four Level 6 Amazons -Sirius's bodyguards are even his harem of women, but don't let that distract you- this guy may appear to be very nice, but he is a savage killer, and the rumor of him being a Werewolf is true (as if his name and "Lycanthrope" as his class during the daytime didn't tip you off earlier).. Hit him with a white magic weapon (such as the Rune Axe given to you by the monk at the temple earlier) to make him howl in pain. Sirius is also as dumb as a brick, and magic works well on him, so do what you need to to send Sirius to the big kennel in the sky. 6-DENEB'S GARDEN- Deneb (***recruitable!***) Level 10 Witch HP-125 Bodyguards- Four Level 8 Pumpkinheads -Her Pumpkinheads can deal some hurtful damage if you're not careful, but take note that she is in the front row (and thankfully not the back, or a Paralyze spell from her could make these fights last an ETERNITY!) and hit her with physical attacks. Avoid magic as she's quite intelligent and magic spells will most likely miss her. She's quite fast, too, so even physical attacks are bound to miss here and there. After the fight, she will ask for your forgiveness. However, she does heavily affect which ending you get, so think about if taking such a malignant woman with you is really worth it. Remember, her beauty and innocent appearance hide her true side. 7-SLUMS OF ZENOBIA- Debonair Level 11 General HP-148 Bodyguards- Two Level 9 Red Dragons Use against- Ashe ***Debonair has a special attack set. He will physically attack you twice with his sword, and then will use "Sonic Blade" on his third attack, which is ranged and can hit any member of your unit. -Ashe apparently knows this bad dude, and the two of them hit off an ugly conversation before the rumble begins. Take note that Debonair is a General and as such is a VERY powerful opponent. He is extremely agile, strong, AND intelligent (as you will find ALL General bosses to be) so throw your best stuff at him. Watch out for his Sonic Blade attack, in essence it is a Sonic Strike attack that does not take away his own HP, and can deal a MASSIVE amount of damage, up to 80 points on one strike if you are not careful. Upon beating him, he will retreat, leaving you happy with the fact you have recaptured the former capital of the Old Kingdom. 8-ISLAND AVALON- Gares Level 12 Dark Prince HP-162 Bodyguards- Two Level 10 Black Dragons Use against- Aisha ***Gares has a special attack set. He will attack with "Evil Ring" first, and then he will smash you twice with his two-handed battle axe. -Prince Gares (Empress Endora's son), hands down, has to be one of the COOLEST looking enemy bosses in the game. Too bad you can't get a guy like him in your army. Clad in a suit of jet black armor, Prince Gares is really sinister. He is pretty much General Debonair on steroids, so look out. Evil Ring will HURT really BAD, especially if you send a high Alignment unit to fight him. Equip some holy weapons to fight him, and ironically, electrical attacks seem to be very effective as well. I'll give you a hint right now- you will see him MANY more times in the future, as (spoiler), he has the ability to "clone" himself and possess his suits of armor with his spirit. 9-KASTOLATIAN SEA- Porukyus Level 13 Nixie HP-169 Bodyguards-Four Level 11 Mermaids -Porukyus is really mad that people are using her kind as food, so, you gotta teach her a lesson. She is extremely intelligent and her Ice Storm attack will HURT when she casts it, hitting your whole unit. Thank god she only does it once. Try Fool carding her bodyguards and then physically whacking her. Due to the fact she's a water dwelling creature, hit her with electrical attacks (via spells or magical weapons) and fire also works well. 10-DIASPOLA- Norn (***recruitable!***) Level 12 Shaman HP-149 Bodyguards- Two Level 11 Titans -Norn is a sad and depressed Shaman, demoted by the Empire, and assigned to govern the prison district of Diaspola. She is actually General Debonair's fiancee (she's very sad as she thinks you killed Debonair), so getting her to join you will help you. She is extremely easy to beat, due to the fact she cannot attack (she only heals herself or the Titans with her). After the fight, spare her life, and if your reputation meter is high enough, she will follow you adamantly, though mostly only because of you telling her that Debonair is alive :) She is a VERY useful ally, extremely intelligent and fast as well. She starts out with low Alignment, though, so just be wary. Have her maul a group of undead a little later on and that won't be a problem anymore. 11-KALBIAN PENINSULA- Figaro (***item: "Durandal" sword***) Level 15 General HP-167 Bodyguards: Two Level 12 Black Dragons Use against- Debonair ***Figaro has a special attack set. He will strike you twice with his sword (which is a black attack as he is using his sword "Durandal" on you) and his third and final attack is "Down Claws", a very, VERY nasty ranged attack that will deal an insane amount of damage to one character in your party. -Approach General Figaro with caution, he is very strong. Use your strategy against him like you did against Debonair earlier, primarily, get rid of his bodyguards with a Fool card. If you have General Debonair (acquired from Shangrila), the two will be astonished to find themselves on opposing sides, and after Debonair's attempt to persuade Figaro to come with him, Figaro refuses, still having faith in Empress Endora, and the two friends will fight each other. General Debonair is very sad that he must kill his best friend, but all is not lost. After the fight, Figaro will give you his sword, and with his last breath, urges Debonair to fight on in his stead, and to stop the Empress before it is too late. Note that you will ONLY get the Durandal sword if you use Debonair to fight him. Be sure to use General Figaro's "Durandal" sword, it is a VERY powerful magical weapon, giving a high strength bonus, as well as being laced with black magic powers. 12-VALLEY OF KASTRO- Ares Level 16 Ravenman HP-215 Bodyguards- Two Level 12 Ninjas, two Level 13 Ninjas Use against- Rauny -Ares has a TRUCKLOAD of health for a Ravenman, much less someone at only level 16!!! Use Rauny to confront the black-feathered bandit, and hope for the best. Ares is not that strong of a boss (he only does one Firestorm attack, it hurts, but he only does it once, and it only hits one person) but he is VERY tough (not only with his huge weight in hit points, but he's also really damn resistant to magic attacks!), which can make the fight aggrivating as his bodyguards will do the bulk of the damage. Try and hit him with white magic weapon attacks, but that will be difficult, since he is half bird, half man, and as a result, is really agile and will be difficult to hit. 13-BALMORIAN RUINS- Albeleo Level 17 Enchanter HP-158 Bodyguards- One Level 15 Stone Golem, one Level 14 Black Dragon Use against- Saradin -Albeleo is a former student of Sage Rashidi, and he is apparently practicing forbidden arts of necromancy and resurrection, and as such is why he looks like a young man, whereas Saradin (his former friend) is very old, with both being the same age (somewhere over 100). Albeleo may have dark intentions, but remember he is an Enchanter, and as such ironically has very high Alignment and is resistant to white magic attacks. His flaw? Use his own type of magic ("Acid Cloud"- physical) against him, he doesn't like physical magic. Send Saradin in and have him put the smack down on his former friend. Do be careful, though, as he does attack twice with his all-hit Acid Cloud attack, and he's also quite intelligent, so he will most likely dodge your magic spells. Ironically, for a magic user, he is also really agile, and as such, he can dodge physical attacks. But don't worry so much about that- he is a wizard, and as such has low strength, so if you connect with a physical attack, he will feel it :) Upon defeating Albeleo, his body and the remains of him will mysteriously vanish into thin air (makes sense, as he's the boss of the SUPER hidden stage, "Dragon's Heaven"). Hidden Stage Alpha-MUSPELM- Slust (***recruitable!***) Level 17 Dragoon HP-198 Bodyguards- Two Level 15 Gold Dragons -You might as well be trying to fight a tank because in general that's how tough a Dragoon really is. After all, he is the warrior servant of the Wind Gods, so one would expect he's a walking bad-@$$. Slust will only attack you once per combat- with a Sonic Strike, which will deal in excess of 100 damage. He's also so fast that he will most likely go before everyone else, so make sure everyone's HP is over 100, or he could put the smack down on a member of your party, killing them instantly. Get rid of his guards and pray that your attacks hit him. He's not invincible, but he's just really damn tough. However, on the bright side, when you do defeat him, if your Reputation, Alignment, and Charisma are high enough, as well as if you have the Star of Heroes, you will break Rashidi's control over him, and he will come with you! Hidden Stage Beta-ORGANA- Fenril (***recruitable!***) Level 17 Dragoon HP-176 Bodyguards- One Level 13 Iron Golem -Fenril is the female counterpart of Slust (and she wears blue armor whereas he wears red), and is another supreme warrior of the Wind Gods. She's basically the same as Slust, only with less strength and HP, but with more agility and magic resistance. She attacks in the same manner, too, with a high-powered Sonic Strike, so use your same tactics against her as you did with Slust. She will also join you if your Reputation, Charisma, and Alignment are high enough, and if you have the Star of Heroes. 14-CITY OF MALANO- Apros Level 18 Vanity HP-221 Bodyguards- Two Level 16 Demons Use against- Tristan or Rauny ***Apros has a special attack set. All of his attacks are black magic spells, which he uses three times. He will either cast Meteor, Phantom, or Nightmare, choosing whichever at random (hope that he chooses Nightmare, it only hits one person!) -Governor Apros is a shrewd, rude, and crude dude. He has been gifted with the powers of black magic, and as such is a powerful opponent. Whack him with holy, lightning, or physical magic attacks and physical force attacks, and he will go down. Throw a World card and he won't even be able to hurt you. He dishes out damage really well, but he doesn't take it very well. Have Rauny or Prince Tristan confront him and let them get their revenge for all the people he's killed. 15-THE TUNDRA- Mizal Level 19 Seraphim HP-184 Bodyguards- Two Level 16 Ice Giants Use against- Yushis -Mizal was once the Chief Angel in heaven, but had fallen to Rashidi's temptations, and she was cast out of heaven. I guess God gave her the big boot. :) Mizal is a fallen angel, but she still uses her white magic attacks, of which is "Jihad", a spell that will hit and heavily damage your whole unit. Mizal is a tough opponent, but hit her with black attacks and she will take heavy damage. Be sure to have her younger sister Yushis confront her. 16-ANTALIA- Omnicron (***item: "Undead Staff"***) Level 20 Sorcerer HP-168 Bodyguards- Two Level 16 Black Knights, two Level 19 Black Knights -Omnicron is the evil magician working for the Empire, and he created the Empire's undead army in the former kingdom of Horai. Omnicron is VERY powerful (he's a Sorcerer, so watch out for TWO all-hit magic attacks). He is susceptible to the same weaknesses Magi and Wizards are, though, so tackle him with physical magic and attacks and he will succumb. Revisit the castle of Kander Hall after the battle to receive his Undead Staff from a Monk who says "I found this in Omnicron's room", which you can use on one of your own Magi and turn him into a Sorcerer. Hidden Stage Delta-ANTANJYL- Galf (***recruitable!***) Level 18 Devil HP-206 Bodyguards- Two Level 16 Phantoms, two Level 17 Phantoms -Galf is one of the evil gods that sided with the forces of darkness and disorder in the first Ogre Battle, and is now sentenced by the Wind Gods to be stuck on earth in this cursed land. Galf is very tough, his only real weakness being holy attacks, and his bodyguards are undead, so bring along a healer or holy weapon/magic attacks to blow his guards away easily. If you use white attacks on Galf he isn't really all that tough.. :) 17-SHANGRILA- Gares Level 21 Dark Prince HP-211 Bodyguards- Two Level 18 Salamanders Use against- Tristan ***Gares has a special attack set, however it is the exact same as the first time you met him, only just stronger. -THIS choad again? Well, apparently, this time Gares has some darker armor, a purple cape, and a meaner attitude. I don't think he kindly took the beating you gave him at Avalon. Gares is just stronger this time, so just use the same approach and strike hard, fast, and with holy power or lightning if you can. Send in Prince Tristan and let him get his revenge against the REAL murderer of the royal family. If you have Norn in your army, you will also find General Debonair here, locked up in chains and in a cell for "war crimes". Free him and he and Norn will kiss and make up, and then General Debonair will join the Rebellion! 18-FORT ALAMOOT- Castor Level 22 Gemini Twin HP-275 Bodyguards- None 18-FORT ALAMOOT- Polkes Level 22 Gemini Twin HP-275 Bodyguards- None ***The Gemini Twins have a special attack set. Each battle Castor will first attack with Super Nova, then Polkes will attack with with a karate kick (physical attack), then Castor will kick, then Polkes will attack with Wind Shot, and then finally, the one in the back row will throw the one in the front row into one of your units (this is called their "Gemini Attack", and it will do INCREDIBLE damage), and then they will switch places from back row to front row (and vice versa). -The two Gemini Twins are two VERY powerful opponents. In my opinion Polkes (who strikes me as the younger brother) is the nastier half of the two, but both are still insanely tough. Hit them hard with the most powerful unit you have, and leave no prisoners. Their only real weaknesses is Castor is weak against fire and Polkes is weak against physical and black magic. They are very strong physically, so rely on magic to try and kill them. They are fairly intelligent, but not as intelligent as previous bosses Omnicron, Gares, or Ares. And on one final note, you must kill BOTH of them to win the stage, NOT just the leader. Hidden Stage Gamma-SHIGULD- Fogel (***recruitable!***) Level 21 Dragoon HP-230 Bodyguards- One Level 20 Tiamat -Fogel is the third Mystic Knight, the bad-@$$ in green armor, the only one who is "cursed", and is the most powerful of the Dragoons that you will run across. He attacks the same way (with a Sonic Strike), and has high resistance to attacks., I had noticed. If you thought Slust and Fenril were walking tanks, get a load of Fogel. Fogel not only has probably one of the most BEEFED statlines I have ever seen, he makes the other two Dragoons look almost like children, and check out the things he can recruit! Salamanders, Gold Dragons, and Tiamats, oh my! ***DROOL...*** No doubt the best special character in the game, hands down. :) 19-DALMUHD DESERT- Prochon Level 23 Ninja Master HP-231 Bodyguards- Two Level 21 Ninjas, two Level 22 Ninjas -Prochon is the Black Assassin, who assassinated the former king of the Ofays kingdom because Ofays resents the ninja code, and then he joined the Empire. Prochon is UNGODLY agile and VERY intelligent (so his all- hit Ninjutsu attack will REALLY hurt!) so don't expect a lot of attacks to hit him (which is really ANNOYING). Well, he is a ninja, so, I would imagine (and almost hope) he would have those attributes. Prochon's Ninjas need to be disposed of, and Prochon's only weakness is his staggering low tolerance to take white magic attacks well, so whack him with Jihads, Starlights, Rune Axes, or whatever to bring him to his knees. He relies mostly on attacks missing him, so connecting a hit should hurt. 20-THE RYHAN SEA- Randals Level 24 Vanity HP-282 Bodyguards- Two Level 20 Black Knights, two Level 21 Black Knights ***Randals has a special attack set, identical to the type of attack set that Apros had earlier (whom you fought at Malano). Randals is just a more powerful version, as basically "Vanity" is the character class of a nobleman imbued with the powers of black magic. -The crooked "Cardinal" Randals (labeled mistakingly as "Randross" in his unit description and "Rudolph" in the prologue) rules the beautiful Ryhan Sea. He bought his title of "Cardinal" when he joined the Empire and gave them a lot of his riches and secrets from his days as a monopolizer merchant in the days before the war. Now he imposes an extremely heavy tax and lives like a king in a luxurious castle. Now it's your job to storm it and take out this filthy piece of scum. Hit him with powerful attacks such as physical magic and white attacks to end his days of slouching around doing nothing to earn his luxurious living while he lives up "the high life". 21-FORT SHULAMANA- Previa (***item: "Mystic Armband"***) Level 25 General HP-258 Bodyguards- Two Level 21 Ravens, two Level 21 Devils Use against- Tristan ***Previa has a special attack set. He will strike you twice with his sword, and then cast "Meteor" on you as his third and final attack. -General Previa, the third of the Four Devas, heavily practices the black arts, and boy does it show here! Not only is his alignment low and his resistance to white attacks really bad, but he casts Meteor as his last attack! Ouchies! Just whack him with everything you've got, and send Prince Tristan after him, as it is believed he is holding Tristan's mother, Queen Floran, captive in prison at Fort Shulamana. You will receive the Mystic Armband after the battle if you send Tristan to confront and kill General Previa. 22-SHRINE OF KULYN- Luvalon (***items: "Holy Grail", "Bizen" sword***) Level 26 General HP-276 Bodyguards- Four Level 22 Samurais ***General Luvalon has a special attack set. He will attack you twice with his Bizen sword (counting as a black attack), and then he will use "Extinction" as his third and final attack, a VERY powerful ranged attack that will strike one character and deal a massive amount of damage, usually more than enough to cause instant death if their HP is below 150. -General Luvalon is the last and most powerful of Empress Endora's Four Devas. He was sent by Empress Endora to find the Holy Grail, one of the last hopes for her to create an invincible army and unite the continent under her iron fist rule again. Luvalon is somewhat weak only against fire, he is INSANELY strong against everything else, due to the fact that he also killed one of the Great Dragons, and was bathed in its blood. You MUST fight Luvalon "honorably" if you wish to get the Grail when you return to Kulyn, which means you ***CANNOT RUN AWAY OR USE TAROT CARDS AGAINST HIM OR HIS UNIT***. This is easier said than done, on account he has a strong bodyguard, and his Extinction attack will easily deep-six an ordinary party member if he connects. After the battle, if your Reputation is high, he will say that he was at least proud to have met and lost to such an honorable warrior such as yourself, and he will give you his Bizen sword before dying. He may have been fighting for the enemy, but at least he was a good-natured person just fighting on the other side. 23-THE CITY OF XANADU- Hikashi Level 27 Highlander HP-275 Bodyguards- Two Level 22 Muses, two Level 23 Muses Use against- Rauny ***Overlord Hikashi has a special (and NASTY) attack set. He will first attack with Wind Shot, then he will attack three times with his broadsword, and finally he will attack with a Sonic Strike, totaling for FIVE attacks (**shudder**) -Overlord Hikashi is not only Rauny's father, but he's also the supreme commander of Empress Endora's Imperial Army, and he is also her own personal bodyguard, which means you have to come through him first if you want to get to the Zeteginean Castle and Empress Endora. He's also the BEST knight the Empire has to throw at you, and here he is. He is only weak against black magic (on account he is a Highlander, the highest ranking form of knight), and is strong against everything else (but not as resistant as Luvalon was to magic). Ironically, Luvalon, in general, has higher stats, but due to the fact that Overlord Hikashi attacks five times (one of which whacks your whole unit and the other almost as good as Luvalon's "Extinction"), he's the deadlier opponent. He also has the nastiest set of bodyguards in the whole game (FOUR Muses! OUCH!) Confront him with Rauny, and a saddening conversation will take place, in which Rauny must defeat and kill her own father. Upon defeating Hikashi, the city of Xanadu will be yours, and the final road to the Empire's capital will be open. 24-ZETEGINEA- Endora Level 28 Black Queen HP-287 Bodyguards- Two Level 24 Black Knights Use against- Debonair or the Lord (ie, yourself) ***Empress Endora has a special (and particularly NASTY) attack set. She will cast X-Magic FIVE times on you, choosing from virtually any all-hit magic spell in the book. BEWARE!!! -FINALLY, you have reached the front door of the Zeteginean Empire's capital, and are poised to confront Empress Endora herself and bring justice to the female tyrant who has brought much pain, suffering, and misery to tens of thousands of people, and who watches children suffer in pain with a smile on her face! On a weird note, for being in her early 50's or late 40's, I have to say she's quite the looker. The damn picture of her looks like a 20-year old woman who takes too much time doing her hair and putting on makeup and lipstick. :) DO NOT confront her without a World tarot card, or I have to say that with all that magic she'll be casting, she will most likely beat the living BEJEEZUS out of your ENTIRE unit. So if you don't want to get smeared across the wall, throw a World card before the fight even STARTS. Confront her with either yourself or General Debonair, and a VERY ugly conversation will ensue before the fight begins. Simply throw EVERYTHING powerful you have at her, this is a no-holds-barred cage match in which she'll be trying to do the same to you. Kill her to finally end the... WHAT?! The game's not OVER?! Sage Rashidi and Prince Gares escaped to the temple of Shalina?! OH NO! Whatever shall the Rebellion do?! Simple. Follow them, knucklehead! And damn, after having to fight those practically endless clones of Prince Gares!!! :) 25-TEMPLE SHALINA- Gares Level 26 Dark Prince HP-242 Bodyguards- Four Level 24 Wraiths Use against- Debonair ***Gares has a special attack set. It is the same as his attack set in all your other encounters with him, just stronger. -FINALLY, you get to kill this mo'-fo'! You have finally found the REAL Prince Gares, so beat the crap out of him and send him to hell! Toast his undead bodyguard, and then put an end to his evil shinanigans once and for all! Send General Debonair after him and kill him to finally confront... 25-TEMPLE SHALINA- Rashidi Level 29 Wiseman HP-328 Bodyguards- Two Level 27 Black Knights Use against- Saradin, Yushis, Tristan, or the Lord (ie, yourself) ***Sage Rashidi has a special (and really NASTY) attack set. He will cast all-hit magic FIVE times (very similar to Empress Endora), only difference being he can choose from ANY all-hit magic spell in the game, be it Meteor, Super Nova, Ice Cloud, Jihad, or whatnot. SCARY. -OMG, Sage Rashidi is a walking TANK! I bet Rashidi could take on Metal Gear with his bare hands. :) Fully doped up with tricked-out magic spells and a near eternity of hit points, Sage Rashidi is really a PINNACLE challenge. DON'T fight him without a World tarot card, or he will utterly ROAST N'TOAST your ENTIRE unit. Throw everything you got at this bad guy, and kill the person who enticed Empress Endora to pull this whole stunt in the first place. You find out that it was really he that was pulling all of the strings, behind Empress Endora. Send his former student Saradin, or Yushis (as he enticed her sister to give him the Black Diamond), or Prince Tristan (as Rashidi was responsible for the death of his parents the King and Queen and the destruction of the former kingdom), or yourself, the Lord, as all of these characters have some MAJOR bones to pick with Rashidi. Kill Rashidi and he will break the Black Diamond, releasing.... 25-TEMPLE SHALINA- Diablo Level 30 Diablo HP-410 Bodyguards- None (doesn't need any!! He's SATAN for crying out loud!!!) ***Diablo has a special attack set, ranging from a plethora of special attacks that you've NEVER seen before in this game, ranging from Earthquake (MAJOR damage on your ENTIRE unit), to Death (insta'-kill attack on whole party) and whatnot. Don't even BOTHER with a World tarot card, NONE of his attacks are considered "magical". -OMG!!! The Prince of Darkness HIMSELF!!! JEEEZ, the crap has REALLY hit the fan this time! At least the background really looks cool, with him coming out of the ground and the entire sky is on fire. A stylish way for you to die, at the very least... how kind. :) Rashidi, you moron, what the hell were you thinking? You don't just release SATAN from the Underworld just to accomplish your own needs! Man, what a selfish and stupid individual Rashidi was. :) Well, it looks like you're going to have to stop Diablo with your own power this time (no small task on account this guy is the King of the Black Gods and the entire Underworld!) This is the FINAL battle of this game, so don't hold ANYTHING back, throw EVERYTHING at this guy. If you want to be characterful, have all three Dragoons of the Wind Gods and Yushis and another one of her Seraphim buddies (all representing the heavens) confront him, that would be a real cool "Good versus Evil" battle. Or if not, just pound away with anything. You only have to destroy his upper body (chest, head, and arms) to kill him, as the lower two parts are just weird looking demon-dragons (or something) attached to him. Destroy Diablo to seal him back in the Underworld forever and win the game!!! WHOOO!! In one last humble opinion, if you didn't use a World card on Sage Rashidi, I considered him to be a much greater challenge than Diablo himself! Ain't that just odd, now?! A mere mortal with more power than the supreme god of the underworld? Uh... :) SUPER-DUPER Hidden Stage Omega-DRAGON'S HEAVEN- Albeleo Level 17 Enchanter HP-158 Bodyguards-? -Find out for yourself and have fun. :) Key of Characteristics- -These are the basic statistics of Ogre Battle, many are in most RPGs. HP- Hit Points. The health and endurance of a character. It represents their physical integrity and how much damage they can take before dying. Each time he/she/it is damaged, they will take damage represented in a white numeral. If at any point a character's hit points are reduced to zero or less, they die. White numbers are damage points, greenish-blue numbers are points recovered (such as from a healing spell or a tarot card). Tougher and stronger characters usually have more hit points than weaker ones. STR- Strength. A character's strength influences the damage dealt from physical attacks, and the ability to absorb damage from physical attacks. AGI- Agility. Agility is how fast a character can move. Agility influences your chances to hit with a physical attack, as well as dodging the physical attacks of others. A more agile character will also act in combat sequence before a slower one. INT- Intelligence. This measures a character's ability to cause damage when using magical spells and attacks based on intelligence. Intelligence also influences ability to avoid magical attacks, and ability to absorb damage from magical attacks. CHA- Charisma. This is a representation of how well this person works with other people, and how much they are respected and liked. High charisma is important for ALL character clases, good or evil. There is nothing bad about high charisma. High charisma makes changing into a better character class easier, a low charisma makes it more difficult. Charisma rises/falls depending on who a certain character kills in battle. Killing people stronger than you (ie, higher levels) earns you charisma. Killing people weaker than you will lower it, so avoid picking on weaker opponents, unlike nearly all other RPGs, your reputation and integrity as a character will plummet should you repeatedly beat up weak opponents (as nobody likes a bully!) Charisma also affects your chances of "persuading" a neutral encountered character to join the Rebellion. A charismatic person will easily succeed at it. A loser person will have a very hard time doing it (and most likely will anger the neutral character anyway.) Charisma also rises faster and better when characters are working with other characters that they get along with. ALI- Alignment. This shows how much a person cares for other people, and their intentions towards rightousness or evil. A high aligned person is lawful, courteous, and "does the right thing"; a low aligned person is chaotic, selfish, thinks only of him/herself, and is cruel. Alignment varies depending on what classes you wish to turn characters into. Low alignment is needed for wizards and berzerkers. A very high alignment is needed for paladins and muses. Alignment will rise/fall from battle depending on who that character kills. Killing stronger and/or chaotic characters will raise your alignment. Killing lawful and/or weaker opponents will lower it. Alignement also affects how well you fight at certain times of the day. A lawful person will fight much more effectively during the daytime and worse at night. A chaotic person will fight better during the night and worse during the daytime. Neutral characters fight equally well at all points of the clock, and fight even better during sunset/sunrise. It can be best represented on a scale, to my estimate: 0-10: Evil 11-20: Very Chaotic 21-34: Chaotic 35-49: Neutral-Chaotic 50-60: Neutral 61-70: Neutral-Lawful 71-80: Lawful 81-90: Very Lawful 91-100: Saintly -As a final note, characters fight better when paired with "likes". IE,. LUK- Luck. Luck, fate, karma, call it what you want, it pretty much influences everything a little bit, dodging, attack strength, powerful hits, etc. It also heavily influences the ability to find an item after defeating enemies. Luck is always a good skill, having higher luck is always better. Maximum Parameters- The max for Strength, Agility, and Intelligence is 255. The max for Alignment, Charisma, and Luck is 100. The max for Hit Points is 999 or something close to that (and I've never ever seen anything stronger than around 450 HP in the whole game. If you can get a character beyond 999 HP, show me. I'll either be impressed or call you a buffoon for using so many Vitality Potions and money on one character.) Character Classes Key- (Requirements to get this character) (Description) (Hit Point Bonus at Level Up) (Strength Bonus at Level Up) (Agility Bonus at Level Up) (Intelligence Bonus at Level Up) (Terrain type and size) (Attack Types- front and back row) (Can he/she be a leader?) (Characters can be recruited- only applicable if they can lead) (My rating on how effective they are, 10 being best) (Commentary/Opinions) -These stats are derived from taking notes down when a character gains levels. It isn't that hard to notice how much stats go up per level with each character, but for your reference (and to save you time) I have put these characteristics down. Thanks go to Mr. Anzulovic et al for a couple of these characteristics, mainly those of characters I hardly or ever used (ie, Pumpkinhead, Fire Giant, etc.) 1-Fighter Group- -The Fighter Group is essentially the character classes available to all male, human characters. Fighter (default male character class, available at almost any time) -a short, little guy wearing silver armor and toting a small sword and a shield. HP +5 Str +2 Agi +2 Int +1 Plains, Small Front Row- Slash (x2) -physical Hand-to-hand (ie, HTH) attack Back Row- Slash (x1) -physical HTH attack Cannot be a leader Can't recruit Rating-3 -Fighters are... well, decent fighters. :) They will be one of your bread n' butter characters early on in the game, but make sure these guys get stuck in often and early so they can level up and turn into more useful classes. Fighters outlive their usefulness by roughly the fifth stage. Change their class, too, as their level up bonuses aren't that great (especially that low +1 Intelligence, and +2 Strength is horrible for a male character.) Knight (Fighter- Level 5+, Cha 50+, Ali 50+) -a taller Fighter, wearing full plate armor, and carrying a longsword, shield, and wearing a blue cape. HP +5 Str +3 Agi +2 Int +1 Plains, Small Front Row- Sword (x2) -physical HTH attack Back Row- Sword (x1) -physical HTH attack Leadership ability Recruits- Fighter Rating-5 -The Knight is your basic "I'm a good guy" unit. He's strong and relies on physical attacks. Essentially a Knight is a better version of a fighter, and can also lead units. However, once a Knight reaches level 7, I would recommend switching him to a Samurai, as Samurais get better bonuses when leveling up, unless, of course, you like the look of the Knight. Paladin (Knight- Level 15+, Cha 60+, Ali 70+) -The same figure of a Knight, only in shimmering gold armor! HP +6 Str +3 Agi +2 Int +2 Plains, Small Front Row- Sword (x3) -physical HTH attack Back Row- Healing (x1) -magical healing spell Leadership ability Recruits- Knight, Cleric Rating-9 -Paladins are terrifying holy "ultimate good guy" troopers. They are among some of the most powerful hand to hand fighters in your army and receive huge bonuses when leveling up (check out the Hit Points!) They also strike THREE times in the front row, making him an ideal crusher. Paladins are one of my favorite units. They can also be stuck in the back row for a cheezy way to kill undead characters. Other than that, leave him in the FRONT, unless you have a really good reason to put him in the back for the single healing spell he'll cast. Vampire (Knight plus special item: "Blood Kiss") -A pale white-skinned Dracula type character, wearing black clothing and wearing a sinister navy blue high collar and cape. HP +4 Str +3 Agi +2 Int +4 Forest, Small Front Row- Life Suck (x2) -drains target of its HP and gives it to him Back Row- Charm (x2) -confuses an enemy and makes it attack its allies Leadership ability Recruits- Werewolf Rating-7 ***During the day, the Vampire is in his coffin, as coming out without his Ray-Ban sunglasses would be extremely hazardous to his health :) and his "Sleeping (x1)" attack in the Front or Back does absolutely nothing. His only upside to being in his coffin during the day is his casket's insane magic resistance. -The Vampire is a little bit of a mixed bag. He is definitely an interesting character and the way you get him is certainly weird. You have to get a "Blood Kiss" item to turn a Knight into a Vampire. But they are cool, as confusing enemy characters that have attacks that attack a whole squad is really fun. :) Plus, he's the only guy in the game that can recruit Werewolves, so, I'd get at least one and make a dark unit of a Vampire and four Werewolves. Make sure they don't fight during the day, though, but during the night these guys will own enemy units. :) Samurai (Fighter- Level 7+, Cha 50+, Ali 50+) -A purple and gray robed warrior wearing ancient Japanese Samurai armor, carrying a katana sword and wearing a samurai-style helmet. HP +5 Str +3 Agi +3 Int +2 Plains, Small Front Row- Ianuki (x2) -physical HTH attack Back Row- Sonic Strike (x1) -ranged physical attack. The Samurai sacrifices some of his own spiritual strength to unleash a VERY powerful attack. The hit will do a lot of damage, but the Samurai will also take, in return, a fraction of that damage on himself. Leadership ability Recruits- Fighter Rating-6 -Samurais are probably the best hand-to-hand fighter unit up until people start changing into the powerful classes at level 15 or so. Samurais are just plain better than Knights, so I turn all my physical bruiser types into Samurais when they hit level 7. Their front row attack is the same as a Knight's and Fighter's, it just looks cooler (as he raises his katana high above his head and then slices directly downward!) His Sonic Strike attack in the back is very powerful as well, and looks cool, as the katana makes multiple images of itself when he raises it up to strike, and then when slashing downwards, he sends a large blue shockwave into his target. Beware, though, even though this attack is powerful, he only does it once per battle, and he will take a fraction of the damage himself that he inflicts with it. If you are facing a Dragon or other large monster, a Sonic Strike can do some serious damage to it. Samurais and Samurai Masters are very good "giant killers". Samurai Master (Samurai- Level 15+, Cha 60+, Ali 70+) -The same appearance as his lower counterpart, only wearing orange/tan/red clothing and armor. HP +5 Str +3 Agi +3 Int +2 Plains, Small Front Row- Ianuki (x3) -physical HTH attack Back Row- Sonic Strike (x1) -same as Samurai's Sonic Strike attack Leadership ability Recruits- Samurai, Ninja Rating-9 -The Samurai Master is pretty much nearly the equivalent of a Paladin. Only one less HP and one more Agility per level up, though, but the Master's back row attack is certainly a lot more effective. The Samurai Master is another ultimate "good guy", who has high alignment and charisma, and is good at liberating cities. They are the true masters of spiritual inner strength (rather than the "Holy Crusader of God", of which is the Paladin), and unlike a ninja assassin, the Samurai Master is the honorable fighter, a strict "warrior's code" kind of man. They do, however, work well with Ninjas and Ninja Masters, and are a more "shock trooper" role compared to the stealth and sneakyness of a Ninja or Ninja Master. These guys are insanely powerful in the front row. Three attacks is excellent, as I always say, "the more attacks, the better". The Samurai/Master would be my character class in any RPG, they just match my personality and are downright awesome. Paladins and Samurai Masters are hands down the best small character class front- line fighters, minus the Dragoon or General, of course. Berzerker (Fighter- Level 6+, Cha 50+, Ali 0-40) -A short and burly bearded man carrying a shield and a big smacky- hitty-poundy hammer :) HP +6 Str +3 Agi +2 Int +1 Plains, Small Front Row- Smash (x2) -physical HTH attack Back Row- Smash (x1) -physical HTH attack Leadership ability Recruits- Fighter Rating-5 -The Berzerker is your above average Knight. Essentially they are not as "good natured" and acquire more HP per level. However, there is a price to pay to taking the evil path... a Black Knight is not as powerful as high "good guy" counterpart, the Paladin. However, if you want an evil knight (and more intelligent and uses magic in the back), then pursue the path of darkness. :) Black Knight (Berzerker- Level 16+, Cha 60+, Ali 0-30) -A heavy black armored knight with a horned helmet and a sinister dark blue cape, and a big axe! Darth Vader in the middle ages, I guess. :) HP +6 Str +3 Agi +2 Int +2 Plains, Small Front Row- Smash (x2) -physical HTH attack Back Row- Fireball (x2) -magical fire attack, ranged Leadership ability Recruits- Berzerker, Wizard Rating-6 -Black Knights are just essentially evil Paladins. Screw the holy path, they just have fun and pillage cities, rape the ladies, and loot people. :) He's not as good as the holy guy in the front row, but he's sure better in the back row. Both receive the same stats when leveling up, so take your pick. Personally I went with the Paladins on account they attack three times in the front, but a magic-using Black Knight in the back might not be bad. He recruits Wizards, too, if you're looking for spellcasters. A weird and messed up combo would be placing Paladins and Black Knights into the same unit... it's Darth Maul and Qui-Gon-Jin fighting alongside each other! :) Beast Tamer (Fighter- Level 5+, Cha 50+, Ali 25-65) -A burly bearded and balding man wearing little armor or clothing, and carrying a large whip. HP +5 Str +3 Agi +2 Int +1 Plains, Small Front Row- Whip (x2) -physical HTH attack Back Row- Whip (x2) -physical HTH attack Leadership ability Recruits- Fighter, Hellhound Rating-6 -Beast Tamers are very useful early on due to the fact that they strike twice in the back row. A good combo at the start with them is an all male unit of three Knights in the front, and two Beast Tamers in the back. Beast Tamers don't lead monsters as well, on account monster characters (like Hellhounds, Dragons, Giants, etc) are afraid of whips. However, their advanced classes are very good, especially if you want to shoot for a Dragon Master. Beast Master (Beast Tamer- Level 12+, Cha 60+, Ali 10-50) -Same as a Beast Tamer, only darker skinned. HP +5 Str +4 Agi +3 Int +1 Plains, Small Front Row- Whip (x2) -physical HTH attack Back Row- Whip (x2) -physical HTH attack Leadership ability Recruits- Cerberus, Cockatrice, Wyrm Rating-6 -The Beast Master is a fairly formidable attacker. He gains the highest strength bonus per level that the male human Fighter family class offers, but to tell you the truth, the only big reason to get a Beast Master in your army is to use a Stone of Dragos on him and turn him into a Dragon Tamer! Yowza! Shaiza! :) Dragon Tamer (Beast Master plus item: "Stone of Dragos") -A tall, slender man carrying a rapier and wearing blue clothing, and a helmet shaped like a dragon's head. HP +4 Str +3 Agi +2 Int +2 Plains, Small Front Row- Slash (x2) -physical HTH attack Back Row- Slash (x2) -physical HTH attack Leadership ability Recruits- Dragon, Wyvern Rating-6 -The Dragon Tamer isn't a phenominal piece of work, but he is good to have to turn him into his more advanced form of class, the Dragon Master. The Dragon Tamer, essentially, is kind of like a Beast Tamer/Master, only with a little less on the strong side and more on the intelligent side. His intelligence will come in better use later, as the Dragon Master can use magic. Dragon Tamers will also boost the stats of any Dragons they lead, making them an ideal leader for Dragons (there's a no-brainer). Dragon Master (Dragon Tamer- Level 20+, Cha 65+, Ali 40-60) -Same as a Dragon Tamer, only this guy likes to wear green clothing. HP +3 Str +3 Agi +3 Int +2 Plains, Small Front Row- Slash (x2) -physical HTH attack Back Row- Ice Field (x2) -cold single target magic attack, ranged Leadership ability Recruits- Silver Dragon, Black Dragon, Red Dragon Rating-8 -The Dragon Master is a the super-trooper leader of your Dragons. They aren't phenominal fighters, but look at what they can recruit! They can recruit high level 2nd level Dragons, making them ideal for an easy way to get that Flare Brass or Platinum Dragon you've been scraping for! Even easier, you can recruit a Black Dragon with him at a minimum level of 18, and then INSTANTLY turn the Black Dragon to a Tiamat! SCARY! :) Doll Mage (Fighter- Level 5+, Cha 50+, Ali 30-70) -A tall "anime style" man, with long, flowing braided blond hair, and wearing green robes and carrying a large book. He also has a tiny little doll at his feet, which comes to life and runs into people. :) HP +3 Str +1 Agi +2 Int +3 Plains, Small Front Row- Puppet (x2) -physical HTH attack Back Row- Acid Cloud (x1) -physical magic attack, hits all enemies Leadership ability Recruits- Golem Rating-5 -The Doll Mage is a sort of "good" mage in a way. I guess they practice the art of making inantimate objects real and alive, coupled with the study of alchemy and physical magic, rather than the Wizard path of the black arts. They are almost absolutely worthless in the front row, so put him in the back! Unless of course, you like seeing the ridiculous (and humorous) attack of him animating his "anime-style" doll puppet to come to life and run into someone, doing a pitiful amount of damage, and where most likely it'll probably miss anyway... and the enemy will most likely knock the stuffing out of your Doll Mage in the front anyway. :) His corrosive acid attack hits an entire unit, the only downside is he does it only once, and this can be tough at later stages. They are VERY good, however, at taking out small targets like Faeries, and they are great at killing Wizards and Magi, who despise physical related attacks. Other than that, the Doll Mage ain't that good. But... their upgraded class form, the Enchanter, is very useful. Doll Magi and Enchanters will also boost the stats of any type of Golem they are leading. Enchanter (Doll Mage- Level 14+, Cha 60+, Ali 50-80) -Same appearance as a Doll Mage, only wearing gray/red clothing. HP +3 Str +1 Agi +2 Int +3 Plains, Small Front Row- Puppet (x2) -physical HTH attack Back Row- Acid Cloud (x2) -phys. magic, hits entire enemy unit Leadership ability Recruits- Stone Golem Rating-7 -The Enchanter is basically a souped-up Doll Mage. Really good with two all-hit attacks in the back row this time, and you get to enjoy this privledge when the Doll Mage hits level 14. He also recruits Stone Golems, which are much better versions of a golem than just the standard type. One of my favorite units with these guys is three Paladins/Samurai Masters in the front, and two Enchanters in the back. Makes for a really effective "good guy" fighting team. Ninja (Fighter- Level 6+, Ali 0-49) -A green ninja with a white headband! HAI-YAHH!!! :) HP +4 Str +3 Agi +3 Int +2 Forest, Small Front Row- Shuriken (x3) -physical attack. He chucks ninja starz! :) Back Row- Ninjutsu (x2) -ninja magic, ranged. Comes in three flavors: Katon (fireball), Suiton (cold rainstorm), or Ikazuchi (lightning bolt) Cannot be a leader Can't recruit Rating-6 -The Ninja is quite the bad-@$$, and although a "dark" character (well, they are assassins), they are one of my favorite units. Their upgraded version, the Ninja Master, simply rocks. For such an early point in the game, three attacks is pretty nasty. Keep in mind though, that although they are really fast and strike three times, their blows usually aren't as strong as say a Knight or a Samurai (as Ninjas practice more on finesse, speed, and agility, whereas Knights and Samurais hit the areas of strength and raw toughness), and they don't fight very well in broad daylight. I never expected Shinobi to be that way, either... :) Their Ninjutsu magic in the back is quite interesting, gives you some options to use if you need magic attacks. Ninjutsu isn't as effective as a full-blown dedicated Wizard's attacks are though, but still, it's nice to have someone who can cast some limited attack magic, but yet fights well in the front row. Ninjas in the front row and Wizards/Magi in the back row make for a good "bad guy" unit. Ninja Master (Ninja- Level 16+, Cha 60+, Ali 0-30) -Same appearance, only the Masta' wears black attire! HAI-YAHH!! :) HP +5 Str +3 Agi +4 Int +3 Forest, Small Front Row- Shurkien (x3) -physical attack with NINJA STARZ!!! :) Back Row- X-Ninjutsu (x1) -ninja magic, ranged. Same attack types as the ninja, but this time it whacks the WHOLE enemy unit. Leadership ability Recruits- Ninja Rating-9 -The Ninja Master just plain RULES. Basicly a tricked-out Ninja with leadership qualities. High HP and Agility (FOUR!!!) for each level up, they are, in my opinion, the true "evil" Paladin in the game. You gotta get the alignment REALLY low to get a Ninja Master, but this guy is worth it, and shines best as a mo'-fo' attacker in the middle of the night. Being evil is easier than being good in this game (and many games) anyway. Just level up a lot and kill characters a few levels below you. Or just maul a bunch of Clerics and Angels, and alignment goes down the toilet just as fast. Equally good in the front or back row (high Intelligence each level, too), the question is, do you want three attacks in the front, or do you want him to cast his magic once in the back row? The choice is yours, and he works best with other Ninjas or "evil" aligned monsters such as Tiamats (ouchies, him in the back with two Tiamats? That's scary), Black Dragons, Wyverns, Zombie Dragons, and the like. Wizard (Fighter- Level 4+, Cha 50+, Ali 10-60) -An old, bearded man in green robes carrying a long, knobbly staff. HP +2 Str +1 Agi +1 Int +4 Plains, Small Front Row- Hit (x2) -physical HTH attack Back Row- Magic (x2) -ranged magical attack, strikes one target Leadership ability Recruits- Giant, Hellhound Rating-5 -The Wizard is your basic bread n' butter magician, casting decent attack magic. They can pick from all flavors of magic in the book, minus white (holy) magic. Never put them in the front row, their attacks at such low strength are utterly worthless, and their low strength leaves them susceptible to heavy damage from any form of physical striking attack. Wizards are powerful, and their next step up is relatively easy to get. The Wizard class is strong in mind, but not in body. They move like slugs, so expect them to attack after most of your other characters, and if they are physically attacked, they will most likely get hit, HARD. Keep them in the back row. Mage (Wizard- Level 10+, Cha 60+, Ali 10-35) -Same as Wizard, only wearing tan/brown robes. HP +2 Str +1 Agi +1 Int +4 Plains, Small Front Row- Hit (x2) -physical HTH attack Back Row- X-Magic (x1) -magical attack, hits entire enemy unit Leadership ablilty Recruits- Giant, Cerberus, Imp Rating-6 -The Mage is a good character, casting one all-hit magic spell once per battle. It is, however, tricky to get them to turn into Sorcerers, as from this point on, special items are needed. These cast powerful all- hit magic, even if they can only do it once. Sorcerer (Mage plus item: "Undead Staff") -Same as the Wizard and Mage, only wearing dark gray/black robes. HP +3 Str +1 Agi +1 Int +4 Plains, Small Front Row- Magic (x2) -ranged magic attack, strikes one target Back Row- X-Magic (x2) -magic attack, hits entire enemy unit Leadership ability Recruits- Skeleton, Ghost Rating-9 -Now you are talkin'! The Sorcerer is a very powerful magician that focuses purely on magical attacks. They are very powerful in the back row, doing what the Mage can't- attacking TWICE per battle with all-hit magic attacks. Upon further pursuing the black arts, the Sorcerer is able to conjure up and recruit your basic undead characters, too. You think he's strong? Wait and see if you can get ahold of an Undead Ring to use on him... Lich (Sorcerer plus item: "Undead Ring") -A very frail and pale white-skinned looking man (and I don't mean caucasian, I mean BLANCHE WHITE skin, even if you can only see his hands and part of his face), appearing to almost look dead. He wears all black clothing and wears a shrouded hood over his head, and carries a black staff with a skull on it. HP +2 Str +1 Agi +2 Int +4 Plains, Small Front Row- Cold Eye (x3) -physical ice attack, strikes one target Back Row- X-Magic (x3) -magic attack, hits entire enemy unit Leadership ability Recruits- Wraith, Phantom Rating-10 -OUCH! The Lich is HANDS DOWN the NASTIEST magic user in the entire game. THREE all-hit magic attacks per battle! Bar white magic, the Lich has a wide array of spells to take down virtually any adversary. Pure evil at its finest. He alone is almost always more than enough to entirely slaughter an enemy unit in one combat! And upon becoming the ultimate master of black magic, he himself has started to wither and become comsumed by it and can conjure the most powerful of undead monsters, the Wraith and the Phantom! If you can get ahold of one of these guys, I assure you, you will pee your pants in delight when you see what he can and will do to entire enemy units. Protect him well, though, as he is intelligent, he will have low hit points, so he does not take damage well. Two of the most impervious and nasty "bad guy" units in the game is a Lich and two Tiamats (all in the back), or a Lich and two Phantoms in the back and two Wraiths in the front. Nasty evil power. (End Fighter group) 2-Amazon Group- -The Amazon group, contrary to the Fighter group, contains all of the female human classes in the game. There aren't as many female classes as there are male, but many of them are extremely useful. In this game, women tend to be more Agile and Intelligent than men, whereas men tend to have more Strength and Hit Points than women. Amazon (default female human class, available at almost any time) -A blonde haired woman wearing little clothing, boots, an archer's cap, and carrying a bow and arrows. HP +4 Str +2 Agi +3 Int +2 Forest, Small Front Row- Arrow (x1) -physical HTH attack Back Row- Arrow (x2) -physical HTH attack Cannot be a leader Can't recruit Rating-3 -The Amazon is your basic bread n' butter female human class. Contrary to Fighters, Amazons are better in the back row than they are in the front. Amazons outlive their usefulness around the same time Fighters do, as you want to turn the lovely ladies into classes that are more useful, such as Valkyries, Witches, Clerics, and the like. On a side note, Amazons (and women in general in this game) do not fight as well if placed in units that contain male human characters. Their abilities will be boosted if placed in an all-female unit. Cleric (Amazon- Level 4+, Cha 50+, Ali 50+) -A woman wearing blue "bishop" style church attire, and carrying a staff in the shape of a holy cross. HP +4 Str +2 Agi +1 Int +3 Plains, Small Front Row- Cross Attack (x2) -physical white magic attack, one target Back Row- Healing (x2) -heals one ally/can destroy undead units Leadership ability Recruits- Amazon Rating-3 -Clerics are an easy class to get above the Amazon. They can heal your allies in the back row, and attack with white magic in the front row. An ideal starting all female unit that has decent combat abilities is two Clerics in the front and three Amazons in the back. Class changing from whatever back into a Cleric or whatnot is very useful to instantly destroy undead units and heavily boost the woman's alignment and charisma. I noticed that almost all of the really good female classes involve very high charisma and alignment. Shaman (Cleric- Level 10+, Cha 60+, Ali 60+) -Same attire as a Cleric, only in green clothing. HP +4 Str +2 Agi +2 Int +4 Plains, Small Front Row- Cross Attack (x2) -physical white attack Back Row- Healing (x3) -heals one ally/destroys undead targets Leadership ability Recruits- Cleric, Angel Rating-5 -Shamans are better healers than Clerics, healing three times. They also gain better stats at a level up, and are very useful at killing undead units. Their attack abilities are not very good, however. Monk (Shaman- Level 18+, Cha 60+, Ali 70+) -Same attire as a Shaman/Cleric, only in brownish-gray clothing. HP +4 Str +2 Agi +2 Int +4 Plains, Small Front Row- Cross Attack (x3) -physical white attack Back Row- X-Healing (x2) -heals ALL allies/destroys undead targets Leadership ability Recruits- Knight, Shaman, Cherubim Rating-7 -While I don't think Clerics and Shamans are that great, Monks, on the other hand, are a very different story. They can heal your ENTIRE unit TWICE per battle, they recruit good characters (Cherubim! Yowza!) and they are actually good fighters in the front row with three attacks. Mount up and show those baddies that holy fury is really powerful, yo'! Valkyrie (Amazon- Level 5+, Cha 50+, Ali 35+) -A woman in brass colored armor and wearing a blue cape, and a helmet with eagle wings on her head, and carrying a halberd. HP +4 Str +2 Agi +3 Int +3 Forest, Small Front Row- Slice (x2) -physical HTH attack Back Row- Lightning (x2) -magical lightning attack on one target Leadership ability Recruits- Amazon Rating-5 -Valkyries are outstanding units, and make up a good bunch of folks to back up your Knights. Valkyries, pretty much, are the female class of Knight. Not as strong or durable, but they do cast magic, and thus back up the Knights and Samurais, etc. in the front line really well. Their lightning attacks are very good. Muse (Valkyrie- Level 15+, Cha 60+, Ali 70+) -Same appearance as the Valkyrie, only in shiny silver armor, and wearing an orange/red cape. HP +4 Str +3 Agi +3 Int +3 Snow, Small Front Row- Slice (x2) -physical HTH attack Back Row- Thunder Flare (x2) -magic lightning attack on all enemies Leadership ablility Recruits- Valkyrie Rating-8 -Muses are essentially the female Paladin. They aren't very good in the front row, but they are phenominally powerful in the back row, where their all-hit lightning storms can make short work of an enemy. Very good character, I like to get a good number of them, they work very well with Paladins and Samurai Masters. Witch (Amazon- Level 5+, Cha 50+, Ali 0-65) -A pretty red-haired woman wearing black clothing, a witch's hat, and carrying a rod with a crystal ball atop it. HP +3 Str +1 Agi +2 Int +4 Plains, Small Front Row- Crystal Rod (x2) -physical HTH attack Back Row- Stun Cloud (x2) -paralyze effect magic on all enemies Leadership ability Recruits- Amazon, Pumpkinhead** Rating-4 **There is an item you can get in the game called the "Glass Pumpkin", which will enable Witches in your army to recruit Pumpkinheads. You can only get this item if you forgive Deneb and do a little quest for her. -Personally, I don't use Witches in my army. They do horrible damage in the front row, and they only stun enemies in the back row. It's useful if you want to prevent getting hit by enemy attacks (it's nice when you paralyze that enemy Sorcerer, Muse, or Paladin, for instance) but each enemy character has a chance of waking up when hit by attacks from your allies. Witches are a mixed bag, but I use Muses and Valkyries instead, they actually hurt people. :) For some reason, though, I dunno why, but the Empire seems to use Witches a helluva lot better than I ever could. :) Princess (Amazon plus item: "Dream Crown") -A very beautiful "anime-style" woman in a long, flowing full-body white dress, a long veil atop her head, and a carrying a white pearl staff in her hand. HP +2 Str +1 Agi +2 Int +4 Plains, Small Front Row- Stardust Rod (x2) -physical white attack Back Row- Starlight (x1) -white magic attack, hits entire enemy unit Leadership ability** Recruits- Angel, Faerie Rating-10 **A Princess as a unit leader will give a +1 bonus to ALL of the attacks of ALL of your allies in her ENTIRE unit that she is leading, INCLUDING herself! This means she can use Starlight twice in the back, a Paladin under her command would strike FOUR times in the front row, and not three, and a Muse with her leadership would do her Thunder Flare in the back row THREE times, and not twice! It's like having a permanent "Emperor" tarot card on your unit the whole time before battle! Shiaza! Yowza! Awesome! :) -The Princess is a phenominal piece of work. MAKE SURE SHE IS THE UNIT LEADER. Not only does she possess the MOST POWERFUL white magic attack in the entire game (evildoers beware!), but all of her companions will get a +1 attack bonus for being under her royal command. In my opinion, the Princess is by far the best character class in the game, out-doing even the mighty but frail Lich, on account of her awesome leadership bonus. Unfortunately for you, a Dream Crown is VERY hard to run across. But should you get one, turn one of your nastiest female characters (like maybe Rauny, Aisha, or whatnot!) into a Princess, and have a royal ball! (No pun intended) (End Amazon group) 3-Lycanthrope Group- -The Lycanthrope group consists of men who are half human, half monster. Dr. Jekyl and Mr. Hyde in a sense. They are human during the day and are their monster during the night. They are, in general, very weak during the day, and strong in the night. Lycanthrope (Werewolf or Tiger Man's form during the daytime) -Looks like a Fighter in appearance, only more tannish clothing and duller silver armor. HP +6 Str +3 or +4 (+3 if Werewolf, +4 if a Tiger Man) Agi +3 Int +1 Plains, Small Front Row- Sword (x1) -physical HTH attack Back Row- Sword (x1) -physical HTH attack Cannot be a leader Can't recruit Rating-1 -Their human form is utterly worthless during the daytime, as they are "weak", and can only attack once. Wait until nightfall to see them become their nasty "Mr. Hyde" alter-ego... :) Werewolf (Fighter plus "Werewolf Virus") -An upright standing on hind legs, very shaggy gray-haired dog with big white fangs, carrying a buckler shield and a mace, and wearing a small little baseball cap on his head. :) HP +6 Str +3 Agi +3 Int +1 Mountains, Small Front Row- Club (x3) -physical HTH attack Back Row- Club (x3) -physical HTH attack Cannot be a leader Can't recruit Rating-6 -Werewolves, are, well... strange. Their attack just looks funny, consisting of repeated bashings with their club and bites with their fangs. :) They are, however, very powerful physical "bruiser" type melee fighters, and can go toe-to-toe (or fang-to-teeth if you like) with Paladins and Samurai Masters. He's equally good in the front or back, so toss him anywhere. They get a lot of health per level up, but take in mind that they are stupid- ie, HE'S REALLY DUMB. So Rover doesn't like being hit by magic too much. :) An ideal leader is a Vampire, so there you go, you have a pure "night-owl" unit that is really nasty after the sun goes down. But don't fight while the sun's up, though, or you will get your butt kicked. :) You can get the "Werewolf Virus" by letting the boss Sirius (in Lake Jansennia), in Werewolf form, kill one of your Fighters, and the next time you revive him, your Fighter will be infected and he'll become a Lycanthrope/Werewolf. Rinse and repeat with another Fighter if you like. Or, better yet, just do it the easy way- just get a Vampire and recruit as many as you want! :) Tiger Man (item: "Full Moon Stone") -Ironically, same appearance as the Werewolf, just only with orange and white fur. Although with only a color change, they do look cat-like. HP +6 Str +4 Agi +3 Int +1 Forest, Small Front Row- Club (x2) -physical HTH attack Back Row- Club (x2) -physical HTH attack Cannot be a leader Can't recruit Rating-7 -The Tiger Man may attack one less time than a Werewolf, but his stats are really beefed compared to the canine counterpart, and his magical resistance is a helluva lot better than a Werewolf's. Basically the Tiger Man is a Werewolf on steroids.. Either way, the Tiger Man is probably one of the rarest characters to run across. But still, this pissed-off kitty-cat is one nasty fighter. Goes to show I guess that "the might of the dogs is nothing compared to the might of the cats". Meow meow, scritch scratch, I big bad bobcat, so fear me. :) (End Lycanthrope group) 4-Faerie Group- -Faeries are very cute little girls and women that are around three feet tall (and very small) and flutter around with their butterfly wings enchanting things, living with nature, and playing funny tricks on people. They are VERY fragile characters (one solid dent from a Giant's club could easily send a 79 HP Faerie six feet under), but their abilities can help you. Male faerie characters of course exist, but note that all Faerie characters in this game are female. Personally, I wouldn't want to run into a near butt-naked male faerie. But that's just my take on it. I don't know about other people out there... :) Faerie (basic starting class) -A very cute little red-haired woman wearing almost NO clothing at all, and flies around with cute little butterfly wings. HP +3 Str +2 Agi +4 Int +4 Low Sky, Small Front Row- Slap (x2) -white magic HTH attack Back Row- Kiss (x1) -raises attack/defense power of the person/monster ally that she kisses Cannot be a leader Can't recruit Rating-1 -Faeries, although cute, in my opinion, are totally worthless. They are extremely fast and very hard to hit (not to mention really intelligent little things), but they just have horrible endurance (really LOW HP!) and their attacks are pretty sad. Just watch that enemy Giant connect a club shot with your Faerie and you'll see her in a big world o' hurt. The only reason I've ever taken one with me/recruited one is to later turn it into a Sylph... and even then, I usually forget that anyway and just use a Persuasion Spell on an Imperial units that has Sylphs in it. It's easier. :) Pixie (Faerie- Level 10+, Ali 30-70) -Same appearance of the Faerie, only purple/redish in hair color. HP +3 Str +2 Agi +5 Int +4 Low Sky, Small Front Row- Slap (x2) -same as the Faerie's Back Row- Kiss (x2) -same as the Faerie's Cannot be a leader Can't recruit Rating-3 -Same deal as the Faerie, not that great. Really cute tiny women, but not great. They kiss twice, but, I haven't seen phenominal results with them. They're good at pimp-slapping undead into oblivion, though... :) Sylph (Pixie- Level 20+, Ali 40-80) -Same look as the Faerie/Pixie, only with blue anime-style hair. HP +4 Str +3 Agi +5 Int +4 Low Sky, Small Front Row- Slap (x2) -same as the Pixie's/Faerie's Back Row- Magic Missile (x1) -all-hit white magic attack on enemy unit Cannot be a leader Can't recruit Rating-7 -Sylphs are actually really awesome. Especially with a Princess or something (OUCHIES, all that white magic!!) Their Magic Missile attack looks really cool (magical white fireballs whacking enemies) and they are really fast and intelligent. If you put them in the back row, they will serve you well. BLUE tinted hair? You got me... sometimes I wonder what dirty little things those animators are thinking. They just HAD to make the Faerie class little tiny women wearing basically nothing. :) (End Faerie group) 5-Dragon Group- -Dragons are, well... your big nasty-@$$ monsters that you grew up fearing as a little kid (except for Puff, he was a good dragon), and feared equally if you ever played Dungeons and Dragons, Heroes of Might and Magic 3, or any other type of RPG/fantasy medieval military strategy game. Dragons are insanely tough and the high level class types can cast magic spells that not only can toast entire units, but can equal or best those cast by Magi and Muses. Dragons can follow three paths- the Lawful path (Silver), the Neutral path (Red), or the Chaotic path (Black). Each path of dragon type has specific attacks and perks that are unique only to its class, and REMEMBER- once you send a dragon down a specific path, he CANNOT GO BACK, so keep that in mind. Dragons types are good front-runners that can absorb an insane amount of damage, while keeping weaker members in the back row safe. Dragon (your basic starting class of the group) -A green skinned (scaled?) dragon with wings, hunched over in a combat position, with one mean looking stare and a fearsome array of fangs. HP +8 Str +4 Agi +2 Int +1 Plains, Large Front Row- Bite (x2) -dragon bites with his fangs, physical attack Back Row- Fire Breath (x2) -dragon breathes a fireball attack at the enemy. This is NOT considered a magical attack. Cannot be a leader Can't recruit Rating-3 -Green Dragons are your basic starting class of Dragon. I would recommend that you change classes with them ASAP, as Green Dragons do not gain much intelligence each level. Red Dragon (Dragon- Level 7+, Ali 35-65) -Same appearance as the Dragon, only red-skinned. HP +9 Str +4 Agi +2 Int +2 Mountains, Large Front Row- Bite (x2) -dragon nibbles on the enemy with his fangs Back Row- Fire Breath (x2) -dragon breathes a mighty fireball at one enemy target. This is based on its intelligence, but is NOT magical. Can't be a leader Can't recruit Rating-5 -The Neutral class of Dragon (Red type) is by far the hardest to stay in, because their alignment properties are in the middle, and thus are tricky to maintain. However, the high level Flare Brass is REALLY worth it! Red Dragons are pretty much just better Green Dragons. Salamander (Red Dragon- Level 16+, Ali 35-65) -A tall and fearsome looking bigger version of a Red Dragon, with huge wings, and standing up on his hind legs. HP +10 Str +4 Agi +3 Int +3 Mountains, Large Front Row- Bite (x2) -nibble, nibble, munch, munch! Back Row- Fire Breath (x2) -dragon blows out a big fireball Cannot be a leader Can't recruit Rating-5 -Essentially, the Salamander is identical to a Red Dragon in attacks, it just gets better stats per level up. Keep going for that Flare Brass... Flare Brass (mistakingly labeled "Fire Breath" on the class area) (Salamander- Level 23+, Ali 35-65) -Same appearance as a Salamander, only with orange/brass colored skin, instead of red skin. HP +11 Str +5 Agi +3 Int +4 Mountains, Large Front Row- Fire Breath (x2) -blows a fireball at the enemy Back Row- Super Nova (x2) -Flare Brass breathes out a very large fireball making a massive explosion on all enemy characters. This is a fire elemental attack and DOES count as a magic attack. Cannot be a leader Can't recruit Rating-8 -The Flare Brass (or Brass Dragon if you are so really inclined) is by far the ultimate neutral aligned dragon. The Super Nova attack just looks plain awesome, and the Flare Brass is so tough that when you get him he will easily have over 350 health and can absorb any and all forms of damage without dying. They are tricky to get, but they are worth it, by FAR. They excel either in the front or the back, belching fireballs or novas wherever they want at any or all targets. Black Dragon (Dragon- Level 7+, Ali 0-35) -Same appearance as a Dragon, only with black skin. HP +9 Str +4 Agi +2 Int +2 Plains, Large Front Row- Bite (x2) -crunch and crunch the enemy target with a bite. Back Row- Acid Breath (x2) -dragon vomits corrosive acid on its target. This is a physical elemental attack, but is NOT magical. Cannot be a leader Can't recruit Rating-4 -Black Dragons are the easiest class of dragon to follow. Just toss them at the enemy and kill a bunch of stuff with them repeatedly and watch those levels go up and that alignment go down. I like Black Dragons, they're cool. Tiamat (Black Dragon- Level 15+, Ali 0-35) -Fearsome black-scaled dragon with spikes all over it, standing up on its hind legs, and rearing its arms down on its enemy, while glaring at it with evil eyes. HP +10 Str +4 Agi +3 Int +3 Plains, Large Front Row- Acid Breath (x2) -same as the Black Dragon Back Row- Evil Ring (x2) -Tiamat conjures up an evil spell, causing a fiery inverted pentagram to appear below the enemy unit, and strike them with evil spiritual energy. This hits the entire enemy unit, and counts as a black magic attack. Cannot be a leader Can't recruit Rating-8 -Tiamats are FEARSOME opponents, and are the evil version of a Platinum Dragon and Flare Brass. They are VERY easy to get (and only level 15 needed!) and are quite powerful. The only downside is that they are nowhere near as powerful as the Platinum Dragon or the Flare Brass. Being evil does have its price. You get stronger quicker, but in the long run the good and neutral guys will become much better. Liches and Tiamats are good combos, and Fogel (the cursed Dragoon) works really well with these guys, too. Zombie Dragon (Tiamat plus item: "Undead Ring") -Same appearance as the Tiamat, only with pale green and pink colored skin, appears to be rotting. It looks like Mr. Zombie Dragon might have received a heavy dose of radiation somewhere. :) HP +11 Str +5 Agi +4 Int +3 Swamp, Large Front Row- Acid Breath (x2) -identical to Tiamat/Black Dragon Back Row- Toxic Breath (x2) -belches noxious gas all over the targeted character, counting as a black non-magic attack. This thing may only hit one person, but it really HURTS the target. Cannot be a leader Can't recruit Rating-6 -You probably won't want to toast an Undead Ring on a Tiamat (as the Tiamat then loses it's "all-hit" ability) but Persuasion Spelling a couple in Imperial units is not a bad idea. The Zombie Dragon by far is the TOUGHEST monster in the entire game, and rely on awesome neat attacks- they burp and puke on people. :) They have practically a million hit points, and their magic resistance is through the roof, faltering only agaisnt white magic (and only a few units use that type, so don't worry). I had a Zombie Dragon once with practically over 400 health or something like that, and he was so strong that most physical attacks against him did like only 5-10 damage. :) The Toxic Breath is really powerful, but this guy shines in the front row as just a gigantic sponge, soaking up a lot of damage without suffering much pain in return (and vomiting on his adversaries while going to it!) And believe it or not... with him being a "Swamp" dweller, your unit with him will actually move quite quickly over shallow seas and rivers! I guess Zombie Dragons like water. They are fun to have, but annoying to fight against. Watch out for the ones in the back, you don't want one to burp on you, causing massive damage. Ewww, stinky, burp-gas doesn't smell nice with this one. :) Silver Dragon (Dragon- Level 7+, Ali 65+) -Hunched over in appearance like the regular dragon, only he has silverish/bluish scaly skin. HP +9 Str +4 Agi +2 Int +2 Snow, Large Front Row- Bite (x2) -takes a bite outta the enemy, but not crime :) Back Row- Ice Breath (x2) -breathes out ice crystals at the enemy target, freezing them solid. This counts as a cold attack, and although based on intelligence, it is NOT magical. Cannot be a leader Can't recruit Rating-5 -Silver Dragons are the first class on the road to getting a "good dragon". They are snow type, and such don't travel well on most types of terrain, but they are good to have, especially when you build them up into Gold and eventually Platinum Dragons. Gold Dragon (Silver Dragon- Level 17+, Ali 65+) -Regal in appearance, large, mighty, and squating on his hind legs. He has a silver underbody and flesh, but his thick scales and scale plates are colored gold. HP +10 Str +4 Agi +3 Int +3 Snow, Large Front Row- Bite (x2) -chomps on a single enemy target Back Row- Ice Breath (x2) -same as the Silver Dragon Cannot be a leader Can't recruit Rating-6 -Gold Dragons, like the Salamander, are just a more powerful version of the lesser type of class they are in. The Gold Dragon is a resourceful opponent and takes combat well. I tend to see them performing better than the red and black counterparts. Platinum Dragon (Gold Dragon- Level 24+, Ali 65+) -Same appearance as the Gold Dragon, only his entire body is a shimmering blue and silver mix. HP +11 Str +5 Agi +3 Int +4 Snow, Large Front Row- Ice Breath (x2) -just like the Gold and Silver forms Back Row- Ice Cloud (x2) -breathes out an ice storm that freezes the water and bodily fluids inside all of the enemies' bodies. This counts as a cold attack, hits the whole enemy unit, and is magical. Can't be a leader Can't recruit Rating-9 -The Platinum Dragon is, pretty much, the mightiest of all the dragons in the game. You will really enjoy it if you work hard enough to get one. Fenril works well with the Silver (good) variety of dragons, so I paired two Gold Dragons up with her, and they eventually became really nasty Platinum Dragons. Enjoy its Ice Cloud attack, it is probably the most powerful cold attack in the game. (End Dragon group) 6-Giant Group- -Giants are fearsome creatures and are essentially extremely huge homonids/homo-sapiens. Probably around 12 feet tall and weighing close to 1000 pounds or so. They wield massive clubs and wear the hides of animals for armor. They are in general very big and strong. Also remember that Giants are like dragons- they can't go back from a path they already start down (not like it matters, once they "class up", it's the highest of the class of Giant they can get to.) Giant (default member of this character class) -A big brute of a giant wearing a brown bear fur over his face and body for armor, and carrying a massive club with wooden spikes through it. HP +7 Str +3 Agi +2 Int +2 Plains, Large Front Row- Club (x3) -physical HTH attack Back Row- Club (x2) -physical HTH attack Cannot be a leader Can't recruit Rating-2 -Giants are essentially large bruiser versions of Knights and other human characters. Giants are strong and can soak up damage fairly well. I, however, don't have much of a use for them in my army, I get by on the ones I get for "free" by recruiting Norn, and she doesn't drag along Giants, she drags along two TITANS, by far the best Giant class. Fire Giant (Giant- Level 8+, Ali 0-40) -Looks just like a Giant, only is reddish in color. HP +8 Str +4 Agi +3 Int +2 Mountains, Large Front Row- Club (x3) -physical HTH attack Back Row- Fire Bolt (x2) -HTH attack with fire element thrown in. Cannot be a leader Can't recruit Rating-2 -The Fire Giant, essentially, is your "evil" Giant. I've only seldomly used one, and they aren't that useful. Fire Bolt isn't that phenominal of an attack, all it is is just a physical hand to hand attack with fire elements behind it. Not that good. Ice Giant (Giant- Level 10+, Ali 50-80) -Looks like a Giant, only blue in color. HP +8 Str +4 Agi +3 Int +3 Snow, Large Front Row- Club (x3) -physical HTH attack Back Row- Ice Bolt (x2) -HTH attack with ice element thrown in. Cannot be a leader Can't recruit Rating-4 -The Ice Giant, respectively, is your "good" Giant. I don't put too much into these guys as well, they're not that good, either. They are, however, better than Fire Giants as you see Mr. Ice Giant, for being a good guy, get's an extra +1 Intelligence per level up. :) Titan (Giant- Level 15+, Ali 70+) -Same appearance as a Giant, only orange and yellow in color. HP +8 Str +4 Agi +3 Int +3 Plains, Large Front Row- Club (x3) -physical HTH attack Back Row- Wind Shot (x2) -the Titan creates a gale-force wind that slices up the flesh of enemies. It is a magical spell, physical elemental, and strikes the entire enemy unit. Cannot be a leader Can't recruit Rating-8 -Titans are GOOD. REALLY GOOD. By far the KING of the Giants. Look at the mess of damage they can make in the back row! Believe it or not, Titans are actually quite darn intelligent, and their magic attacks are quite powerful. I consider Titans are REALLY good creature in this game, an even bigger incentive to get Norn- as she comes with two of them! Titans are awesome, you should definitely get a couple in your army. (End Giant group) 7-Canine Group The doggies of Ogre Battle. There are only two classes in the whole game, but they are interesting creatures, even if they are two-headed dogs. Usually that means double the food rations at the table for them, unfortunately. :) As like Giants and Dragons, the doggies can't change class once they level up. Hellhound (default doggy character class) -A massive blue and pink haired two-headed nasty dog. Easy, Rover. :) HP +6 Str +3 Agi +3 Int +3 Mountains, Large Front Row- Smash (x3) -physical HTH attack, doggy bites the enemy. :) Back Row- Fire Breath (x2) -identical to a Dragon's attack. Doggy belches fire. Shouldn't have fed him that Mexican food last night... :) Cannot be a leader Can't recruit Rating-6 -I like the doggy class. I don't know why, but they are really useful early on in the game. Warren drags two along with him, and they're easy to get almost anywhere (frequent in early random neutral encounters, too.) They are quite competent hand to hand attackers, and are quite fast and intelligent. They shine best in the front row. They work well with Wizards and Magi. Ideal for another "dark" unit. Cerberus (Hellhound- Level 13+, Ali 0-60) -Looks just like a Hellhound, only black in color. HP +7 Str +4 Agi +4 Int +4 Mountains, Large Front Row- Smash (x3) Back Row- Mesmerize (x2)/Fire Breath (x2) -Mesmerize is exactly like the Witch's stun cloud attack, except this only hits one person. The Cerberus can also belch fire, too, and they tend to do this after mesmerizing their target. They only attack twice in the back row, and they randomly decide what to use. Sometimes one and one, or two of the same type, etc. Cannot be a leader Can't recruit Rating-7 -The Cerberus is a mixed-bag. Obviously a lot better than the Hellhound, putting him in the back seems like a bad idea. Leave him in the front to do his bashings and bites. They get very good stats each level up. They will eventually become really fast, strong, AND smart. (End Canine group) 8-Birdpeople Group -Birdmen are essentially a sort of "mutant" species of human people who have large bird wings growing from their backs. They are capable of flight, and attack with swooping strikes with their clubs. Female birdpeople do exist, but keep in mind that all birdpeople characters in this game are male. Birdmen in general are very agile. Birdmen cannot interchange between class, they are just like Dragons and Giants. Hawkman (default character class) -A birdperson with white wings and and blue/red feathers/hair. HP +5 Str +2 Agi +3 Int +1 Low Sky, Small Front Row- Club (x2) -physical HTH attack Back Row- Club (x1) -physical HTH attack Can't be a leader Can't recruit Rating-3 -The Hawkman is something I would consider better than a Fighter, at the least. He also flies, but you need to turn them into Eaglemen or better to be effective. They are almost absolutely worthless in the back row. One attack doesn't cut it, especially one hand to hand attack! Eagleman (Hawkman- Level 10+, Cha 50+, Ali 45+) -Same appearance as a Hawkman, only with white/brownish colors. HP +6 Str +2 Agi +4 Int +2 Low Sky, Small Front Row- Club (x2) -physical HTH attack Back Row- Thunder Arrow (x1) -electrical magic attack, ranged. Strikes one target. Leadership ability Recruits- Hawkman, Griffon Rating-6 -The Eagleman is my preferred bird of choice in the group, but I only go for one group of five of them (being lead by Canopus.) They are nice to have, and they're really fast! Their back row attack is quite cool. Works wonders on water enemies and those that wear a lot of armor! Ravenman (Eagleman- Level 12+, Cha 50+, Ali 0-55) -Same appearance as a Hawkman, only with black wings and coloring. HP +6 Str +2 Agi +4 Int +2 Low Sky, Small Front Row- Club (x2) -physical HTH attack Back Row- Firestorm (x1) -magical fire attack, ranged. Strikes one target. Leadership ability Recruits- Hawkman, Griffon Rating-6 -I've rarely used Ravenmen, but that doesn't mean they're worse than Eaglemen. In fact, they're pretty much exactly the same, only Raven's evil, and Eagle's good. I just use Eaglemen because I like being a good guy, pretty much. Ironically, you have to have him be an Eagleman first, before he turns Raven. STRANGE... (End Birdpeople group) 9-Demon Group -Demons, Imps, and Devils are those who are the combative forces of darkness in Ogre Battle. They are the evil minions of the Underworld, but for some reason, some may wish to stop the Empire. I dunno why, maybe they wanna redeem themselves. :) Imp (mistakingly labeled as "Devil" on the status screen) (default character class of the Demon group) -A little devilish dude with dark green skin, carrying a scythe. HP +5 Str +2 Agi +2 Int +3 Low Sky, Small Front Row- Scythe (x2) -HTH attack, laced with black magic Back Row- Nightmare (x1) -one target black magic attack, ranged Leadership ability Recruits- Wizard Rating-3 -Your basic little demon, he comes to the planet in search of assimilating the weak willed. His attacks aren't very good, but keep him around, as when he turns into a Devil, whoa, they're nasty. Demon (Imp- Level 10+, Cha 50+, Ali 0-30) -Same appearance as the Imp, only red skinned. HP +6 Str +3 Agi +3 Int +3 Low Sky, Small Front Row- Scythe (x2) -HTH attack w/black power Back Row- Nightmare (x2) -one target black magic attack, ranged Leadership ability Recruits- Imp, Wizard Rating-6 -A nastier form of demon, the Demon (oxymoron, whoa...) is a better fighter than the Imp, and not only makes an ideal leader for an undead unit, they also have good black magic attacks. Send these guys to kill weak and holy targets. Keep the Charisma decently high, but they don't give a damn (no pun intended, hee hee!) about alignment. Devil (Demon- Level 20+, Cha 50+, Ali 0-25) -Same appearance as the Imp and Demon, only dark brown skinned. HP +6 Str +3 Agi +3 Int +4 Low Sky, Small Front Row- Scythe (x2) -HTH attack w/black magic power Back Row- Meteor (x1) -drops gigantic black meteor on whole enemy unit Leadership ability Recruits- Demon, Mage Rating-8 -Pure evil in its true incarnation, Devils possess the nastiest black magic attack in the entire game. Dropping a gigantic meteor on the entire enemy unit is sure to cause a whole lot of pain, and assuredly also kill any dinosaurs nearby. :) Throw this guy in the back row and watch the ensuing carnage. Putting an Imp/Demon's alignment into the toilet to get this guy is also a lot of fun. :) 10-Angel Group -Angels are the direct opposite of the Devils and Demon group. These are people who work for the good gods and the heavens. Though there are of course male angels, all angel characters in this game are female. Angel (default character class) -A white robed and white winged woman with a halo on her head. HP +4 Str +2 Agi +2 Int +3 Low Sky, Small Front Row- Halo (x1) -HTH attack with white magic power Back Row- Banish (x1) -one target white magic attack, ranged Leadership ability Recruits- Faerie Rating-1 -As much as I don't like to say it, well, Angels SUCK. The "Good" side posesses the worst fighter in the game. Yes, they do, Angels are horrible fighters in this game. You put an Angel against an Imp and the Imp will open up a Stone Cold can of whoop-@$$ all over the poor little Angel. Low stats per level and only ONE attack front or back. NEVER use Angels. Wait until you get Yushis and she'll drag along herself and Cherubims, who are good and respectable fighters. Only use them if you like challenges. But you do have to start somewhere. Angels may suck, but Seraphims are dynamite. You can't always get a Princess when you need one, right? So, get a character who has the next best white magic attack in the game- the Seraphim. Cherubim (Angel- Level 11+, Cha 55+, Ali 60+) -Same look as the Angel, only with purple-looking robes and wings. HP +4 Str +2 Agi +2 Int +4 Low Sky, Small Front Row- Halo (x2) -HTH attack w/white power Back Row- Banish (x2) -one target white magic attack, ranged Leadership ability Recruits- Angel, Faerie Rating-5 -The Cherubim is a phenominal improvement over the Angel, because, well, the Angel is just plain BAD. :) Twice the attack power, and not only cute and good looking, they're also decent fighters. Seraphim (Cherubim- Level 22+, Cha 60+, Ali 80+) -Same look as the Cherubim and Angel, only with gold-red robes. HP +4 Str +2 Agi +3 Int +4 Low Sky, Small Front Row- Halo (x2) -HTH attack w/white power Back Row- Jihad (x1) -white magical spell, strikes all enemies Leadership ability Recruits- Cherubim, Faerie Rating-8 -OMG, ninjas out of ten! Holy smiting at its finest. The Seraphim takes along a pack of dynamite with her, in the form of the jihad! It's the jihad power ten! Jihad is a very good attack, and it also looks awesome (though I thought it was an electrical attack the first time I saw it!) 11-Golem Group -Golems are creatures that are former inantimate objects that have been brought to life through magical animation. They are usually made out of some suitable hard material and are carved in the shape of humans. They are usually extremely strong but lack hit points and magic resistance. Golem -A creature appearing to be made out of stone, wearing a helmet and dragging a ball and chain on his foot. HP +2 Str +4 Agi +1 Int +2 Plains, Large Front Row- Punch (x3) -physical HTH attack Back Row- Punch (x2) -physical HTH attack Can't be a leader Can't recruit Rating-1 -I think Golems are practically useless. The only good Golem in the class is the Iron Golem, and they're hard to get. Golems are flawed against fire and white magic, and take PAIN from them when hit. Their low hit points mean they can be easily killed in only a few strikes, and match them up against a STRONGER opponent like a Dragon or a Giant, and they'll die quickly. I think Golems suck because they also can't "class up". They are permanently stuck in their class they start in. They also move like slugs, and frequently miss what they attack. His fat @$$ also takes up two slots in your unit, and you don't see the Empire using them often, so why should you? :) Stone Golem -Same appearance as a Golem, only black colored. HP +2 Str +4 Agi +1 Int +2 Mountains, Large Front Row- Stone Fist (x3) -physical HTH attack Back Row- Stone Fist (x2) -physical HTH attack Can't be a leader Can't recruit Rating-1 -Well, a Stone Golem sucks donkey balls. Figuratively, you schmuck! Golly... :) Anyway, they're at least somewhat better than a regular Golem. They still move like slugs and have such low HP they aren't worth the trouble. I tossed the ones Saradin brought with him in the trash can, and got something better. Turned him into a Lich and bought Wraiths and Phantoms. :) Iron Golem -Same appearance as a Golem, only dark silver/blackish iron in color. HP +2 Str +4 Agi +2 Int +2 Plains, Large Front Row- Iron Fist (x3) -physical HTH attack Back Row- Iron Fist (x2) -physical HTH attack Can't be a leader Can't recruit Rating-6 -The Iron Golem ain't half bad. His attacks hurt a lot and he has INSANE magic resistance, except he falters against fire (and even there, it still fares better against fire than Ice Giants and the regular Golem!) and gains decent agility per level up for him. The one that Yushis drags along is definitely worth keeping (and that's the only one I use). If you get a Trade Ticket, try blowing some Speed (the potion, NOT the drug, silly!) and Vitality Potions on him to make him quite the formidable opponent. My Iron Golem had an Agility of 130 and 240 HP once. :) (End Golem group) 12-Mermaid Group -Mermaids are just what you know, half person on the upper half and half fish on the lower half. Ariel from "The Little Mermaid" that you probably saw as a kid, basically. There are of course male mermaids, but all mermaids in this game are female. Mermaid (default character class) -A mermaid woman with a purple lower body half. HP +5 Str +2 Agi +2 Int +3 Sea, Small Front Row- Trident (x2) -physical HTH attack Back Row- Blizzard (x1) -one target, ranged magical cold attack Leadership ability Recruits- Mermaid, Octopus Rating-3 -Mermaids aren't that good, but keeping them around until they turn into Nixies is a good idea. They cast decent water magic, and make for a good sea unit in maps that have lots of water. Nixie (Mermaid- Level 11+, Cha 50+, Ali 50+) -Same appearance as a Mermaid, but with a yellow/orange lower body. HP +5 Str +3 Agi +3 Int +4 Sea, Small Front Row- Trident (x2) -physical HTH attack Back Row- Ice Storm (x1) -strikes enemy unit with magical cold attack Leadership ability Recruits- Mermaid, Octopus Rating-7 -Nixies are quite good characters, and I like using the two Mermaids that Aisha drags along with her. Their Ice Storm attack is quite powerful, even though they only do it once. They get very good HP, Intelligence, and Agility per level up, too. (End Mermaid group) 13-Wyrm Group -Wyrms and Wyverns are reptilian creatures that are built like dragons but are smaller. Unlike the Dragons in this game, Wyrms and Wyverns have the ability to fly. Wyrm (default character class) -A green flying lizard with fangs and a really nasty spiked tail. HP +8 Str +4 Agi +3 Int +1 High Sky, Large Front Row- Tail (x2) -physical HTH attack Back Row- Tail (x2) -physical HTH attack Can't be a leader Can't recruit Rating-7 -I like Wyrms and Wyverns. They are extremely fast and strong creatures. In the hand-to-hand aspect, they are better than dragons. They class up into Wyverns very quickly and have a lot of health. And the big kicker is they FLY. Mobility ain't an issue with these guys. They're dumb and stupid, but who needs to be smart when you can just have a bunch of HP to soak up the damage? :) Wyvern (Wyrm- Level 13+, Ali 0-55) -Same appearance as the Wyrm, only dark brown in color. HP +9 Str +4 Agi +3 Int +1 High Sky, Large Front Row- Tail (x2) -physical HTH attack Back Row- Fire Breath (x2) -identical to a Dragon's attack Can't be a leader Can't recruit Rating-7 -The Wyvern is the badder-@$$er version of the Wyrm, and he gets more HP per level. Back row is interesting, he can Fire Breath, but his intelligence is likely to be very low, so keeping him in the front is usually the best idea. They may only attack twice per combat, but with all that strength they'll have, each hit will hurt a LOT. (End Wyrm group) 14-Undead Group -The living dead have returned to the earth, to wreak havoc, angry because their eternal rest has been disturbed. Undead creatures in this game are very interesting and different from many other RPGs (I like this game's style), and they are also powerful. ***NOTE- Undead creatures have no HP (they're DEAD! Dead stuff doesn't have HP!) and are COMPLETELY invulnerable to any and all forms of attack EXCEPT white magic, which will destroy them INSTANTLY. Skeleton -A rotting gray skeleton warrior with decaying rags for clothing, carring a broken shield and a jagged sword. HP N/A Str +3 Agi +2 Int +1 Plains, Small Front Row- Sword (x2) -physical HTH attack w/black power thrown in Back Row- Sword (x1) -same as above Can't be a leader Can't recruit Rating-3 -I don't like Skeletons in this game because I'm the patient type and go for Wraiths that appear later in the game. The Wraith is by FAR better than a Skeleton. Trust me. The thing that sucks about undead is they can't class-up, so they are stuck in the class they start in. Skeletons and Wraiths are also extremely STUPID creatures, so expect them to not dodge a white magic attack directed at them. Wraith -Same appearance as a Skeleton, only brownish-yellow in color- looks like he's been in the soil too long :) HP N/A Str +4 Agi +2 Int +1 Plains, Small Front Row- Sword (x3) -physical HTH attack w/black elements Back Row- Sword (x1) -physical HTH attack w/black Can't be a leader Can't recruit Rating-8 -Wraiths are AWESOME, and are pretty much the dead Paladin and Samurai Master. They attack three times in the front row, and are extremely strong individuals. They're as dumb as rocks, but they still pack a very powerful punch. I like to have two Wraiths in the front and two Phantoms and a Lich in the back for a SUPER evil unit. Ghost -A phantasmal creature, pretty much your average halloween ghost- looks like a floating white bedsheet with an evil smile and evil eyes. HP N/A Str +2 Agi +3 Int +4 Low Sky, Small Front Row- Curse (x1) -physical HTH attack w/black elements Back Row- Nightmare (x2) -black magic attack, one target, ranged Can't be a leader Can't recruit Rating-5 -I like Ghosts at least better than Skeletons, but still, you should be patient and wait until you can get Phantoms, as they are by far a whole helluva lot better. Ghosts and Phantoms make excellent back row fighters, casting their evil magic on the unwary. Ghosts and Phantoms do have good resistance to white attacks, though, they are fast and intelligent, so they're hard to hit. Works both ways, though, as the enemy has the same benefit. :) Phantom -Same appearance as the Ghost, only dark yellow in color. Pretty much picture that bedsheet, only soiled a whole lot of times. :) HP N/A Str +2 Agi +3 Int +4 Low Sky, Small Front Row- Curse (x2) -physical HTH attack w/black elements Back Row- Nightmare (x3) -black magic attack, one target, ranged Can't be a leader Can't recruit Rating-9 -Phantoms are PHENOMINAL! :) They are awesome, with three attacks in the back row, and high intellegence and agility to boot! They make nasty spellcasters, while Wraiths in the front row mix it up with their evil dark swords. Phantoms are awesome, and go great for any evil unit. (End Undead group) 15-Pumpkin Group -The Pumpkin group consists of either magically animated creatures or extremely weird living ones. I have no idea what these creatures are in Ogre Battle, they are living pumpkin people. Don't ask me, and I dunno about you, but if I had a jack-o-lantern for a head, I'd be really pissed-off, too. :) Pumpkinhead (default character class) -A humanoid looking-like person in ragged clothes, except it has a jack-o-lantern for a head, which it uses to attack people. HP +3 Str +2 Agi +2 Int +1 Forest, Small Front Row- Pumpkin (x1) -reduces target's HP by 1/2 Back Row- Pumpkin (x1) -reduces target's HP by 1/2 Can't be a leader Can't recruit Rating-1 -These things are STRANGE. Straight out of Friday the 13th or Nightmare on Elm Street or something. I have no idea what the hell these things are, and thank goody you only encounter them in one Imperial unit in the entire game (Deneb uses them.) These things are pretty much like an "evil clown" of RPGs. Their attack is really interesting, and they are cool to use against a 500 HP Zombie Dragon. It's really funny to see a gigantic "250" pop up for damage. :) But still, I've never seen a real big use for them, and if you don't have Deneb and/or the Glass Pumpkin, these things are RARE to come across. Halloween (Pumpkinhead plus Item: "Rotten Pumpkin") -Same appearance as a Pumpkinhead, only with a green/brown head. Looks like they let his jack-o-lantern sit out and rot for a few days... :) HP +4 Str +3 Agi +3 Int +2 Forest, Small Front Row- Pumpkin (x2) -reduce enemy target's HP by 1/2 Back Row- Pumpkin (x2) -same as above Can't be a leader Can't recruit Rating-4 -Even more mystifying than the Pumpkinhead, the Halloween character smacks the enemy with his gigantic pumpkin head. What's even more disturbing is these things have INSANELY high Luck, of all statistics! I had a Halloween once that had like Luck 92 or something!!! (Uh...?) I still have no idea what purpose these things serve in this game, but if you want to use one, go ahead, I'm sure there are creative ways to use them... (End Pumpkin group) 16-Griffon Group -The Griffon group consists of gigantic flying half eagle/half lion creatures. They are large, fast, and agile. Griffon (default character class) -A large creature, with white eagle feathers and a brown lion body. HP +7 Str +2 Agi +4 Int +1 High Sky, Large Front Row- Tackle (x2) -physical HTH attack Back Row- Wind Storm (x1) -physical magic attack, strikes all enemies Can't be a leader Can't recruit Rating-5 -Griffons are respectable creatures, but I wouldn't recommend using more than a couple in your army, and I like to use them in the back row, as their all-hit attack is decent. A really good "liberator" good- guy unit I like to make is Ashe and two of his Knight buddies in the front, and a Griffon in the back. Highly mobile and decently powerful, and when the Knights become Paladins, it's whoopin' time. Cockatrice (Griffon- Level 9+, Ali 0-60) -Same appearance as the Griffon, only a bland gray/cream coloring. HP +6 Str +3 Agi +4 Int +1 High Sky, Large Front Row- Tackle (x2) -physical HTH attack Back Row- Petrify (x2) -physical magic, attempts to petrify one enemy Can't be a leader Can't recruit Rating-1 -Golly, do I think Cockatrices suck. There's a bug in the PSX version anyway (the version I own and like best) that prevents them from hitting you like 90% of the time or something close to that. Every time I see the petrify attack come up, it practically always misses. Either because they're so dumb, and/or because of the glitch. These things are not worth it, and are one of the only classes in the game I can think of where "classing-up" is actually BAD for you. Leave him as a Griffon instead. They are much more useful. (End Griffon group) 17-Octopus Group -Your friendly neighborhood 8-armed sea-dwelling monsters of Ogre Battle. Octopus (default character class) -An octopus, what did you expect? He's red, and has 8 arms. :) HP +9 Str +3 Agi +2 Int +1 Deep Sea, Large Front Row- Tentacles (x4) -physical HTH attack Back Row- Tentacles (x2) -physical HTH attack Can't be a leader Can't recruit Rating-4 -Octopi, in my opinion, are good fighters (four attacks! WOW!) but I don't find them that practical because they make your unit move SLOW across land, due to the fact they like to dwell in deep water, and as such, are slow on land as they have to slither and crawl their way around. They also don't fight that well on land surfaces. Kraken (Octopus- Level 12+, Ali 55+) -A fearsome brown/tan/gray colored octopus. HP +10 Str +4 Agi +2 Int +1 Deep Sea, Large Front Row- Tentacles (x4) -physical HTH attack Back Row (on water)- Maelstrom (x2) -physical all-hit attack Back Row (not on water)- Tentacles (x2) -physical HTH attack Can't be a leader Can't recruit Rating-6 -The Kraken is a very strong opponent, and gets a lot of health each level up. They still move slow on land, however these things are BEASTS when on water! Their Maelstrom attack in the back row does INSANE damage to enemy units on water (mostly due to the fact he fights better on water, and most other characters SUCK on water), but if your Kraken is not on water, he will only do two tentacle attacks in the back row. A good water unit is two Krakens and a Nixie, especially on the "big water maps" like the Kastolatian Sea, Ryhan Sea, and Shrine of Kulyn, these guys will OWN enemies! (End of Octopus group) Special Group -There are basically only three types of creatures you get here that don't fit in anywhere else. These characters are generally very strong. Lord (ie, YOU in this game!) -Varies in color and appearance, depending on being male or female, and your allegiance (Chaotic, Lawful, etc) from the questions you answered at the start of the game. HP, Str, Agi, and Int all VARY Front Row- (Chaotic) Death Cloud (x2) -black magic attack, ranged, one target (Neutral-Chaotic) Sword (x2) -physical HTH attack (Neutral) Sword (x3) -physical HTH attack (Lawful) Banish (x2) -identical to Angels and whatnot Back Row- (Chaotic) Phantom (x1) -all-hit black magic attack (Neutral-Chaotic) Thunder Flare (x1) -all-hit lightning magic (Neutral) Sonic Strike (x1) -identical to that of the Samurai (Lawful) Ice Cloud (x1) -identical to Platinum Dragon's attack MUST be the unit leader! Recruits- Fighter (male), or Amazon (if female) Rating- Depends on how strong you make yourself! -I don't have much to say, it's YOU in this game! You make yourself to be the way you want, as strong or as weak as you want, you're the one playing. :) General (Debonair and Tristan) -A VERY long blonde-haired "anime-style" warrior with a round shield and carrying a VERY large sword in one hand. Looks kinda like Cloud from FF7, in a way (with long flowing hair and not the spikes!) FF7 must have ripped this look off from Ogre Battle. :) Debonair wears black armor, and Prince Tristan wears aqua blue armor. HP, Str, Agi, and Int vary between both characters. Front Row (both)- Sword (x3) -physical HTH attack Back Row (Tristan)- Sonic Strike (x1) -same as Samurai's attack Back Row (Debonair)- Sonic Blade (x1) -Samurai attack, doesn't lose HP Leadership ability Recruits- Vary between Tristan and Debonair. They both recruit REALLY good stuff like Magi and Enchanters, though! Rating-10 -Generals are insanely good fighters. High magic resistance and insane stats. They are nastier than Paladins and Samurai Masters. You will mostly see Generals as enemy stage bosses (Debonair, Figaro, Previa, and Luvalon), but there are two in this game that you can get on your side. Heck, you even have to give Debonair a beat-down early on before he joins you later in the game! Dragoon (Slust, Fenril, and Fogel) -A tall and slender warrior clad in a sinister suit of armor, wearing a helmet with wings on the end of it in the shape of dragon wings. Slust wears red armor, Fenril blue, and Fogel deep dark forest-green. HP, Str, Agi, and Int per level vary between the three. Front Row (all)- Sword (x3) -physical HTH attack Back Row (all)- Sonic Strike (x1) -identical to the Samurai's attack Leadership ability Recruits- Vary between the three, but all a lot of good stuff, especially Fogel!!! Rating-10 -Dragoons, the three servants of the Wind Gods, are AWESOME, and are even MORE powerful than a General. They are by FAR the most powerful "warrior" class heroes in this game. They are just so tough and strong, and are almost completely untouchable with nearly all magic spells! It'll either miss or you'll laugh at how much pitiful damage they take from an enemy wizard's spells! There are only three in the game, they are VERY hard to obtain (require lots of holy path stuff!) but they are by FAR worth it! Fogel is by far in my opinion the best special character in this game, and put him in ANY one-on-one fight (except Diablo, Rashidi, Hikashi, or Endora) he would beat them. He doesn't flaunt and boast about his strength for nothin'! That's why he's cursed! :) Try putting one in the back sometime and watch how much damage a Sonic Strike from them can do! I got Fogel to dish out about 200 damage to the enemy one time! :) (End Special group, and class checklist) Quick Checklist to Pursuing a Holy Path- -Note that you do not have to do all of these steps if you wish, but to get a really good ending, make sure you obtain most or all of the "good" special characters in the game. Obtaining the Mystic Treasures and the Zodiac Stones will heavily influence your ending type as well. Also consider making your Lord (yourself) character's Alignment, Charisma, and Reputation Meter extremely high. This will also really help. 1-The Castle of Warren Recruit Lans the Knight at Zeltenia. Fight and recruit Warren the Wizard at Volzak, and he'll get the rest of the rebel troopers to join you in your quest. 2-Sharom Border Have Lans confront and fight Usar at Jindark. Obtain the Star of Heroes at hidden temple north of base. 3-Sharom District Recruit Canopus the Eagleman at Bah'Wal. Have Canopus confront Gilbert at Parcival. Forgive Gilbert the Beast Tamer and allow him to join you.. 6-Deneb's Garden Refuse to forgive Deneb. This will give you a big boost in reputation, but your Lord character will suffer a -5 Alignment for your decision. 7-The Slums of Zenobia Recruit Ashe the Knight at Byroit. Hire the mercenary Beast Tamer, Lyon, for $20000 at Anglem. Have Ashe confront General Debonair at Zenobia. Return to Kal Robs and speak with the nanny to get the Key of Destiny. Receive the Garnet Zodiac Stone at a temple here. 8-Island Avalon Recruit Aisha the Shaman at central hidden temple. Receive the Emerald Zodiac Stone here as well. Have Aisha confront The Black Prince, Prince Gares, at Amad. 9-Kastolatian Sea Obtain the Brunhild Sword at the far NW hidden temple at edge of map. 10-Diaspola Give Posha (the little girl at Somyul) a Golden Beehive to cure her mother, and receive a Sentoul Demon statue from her. Fight and recruit Norn at Diaspola by sparing her life after the fight and then asking her to join you (you will suffer a small reputation penalty for this.) Receive the Aquamarine Zodiac Stone at the city of Ajan. Give the Ginger Cake (obtained from the crazy monk in Organa) to Posha and she will find the Pearl Zodiac Stone in it and gives it to you. 11-Kalbian Peninsula Locate the Chaos Gate (it is in the northeast, in the grassy areas) Have Debonair confront his friend, General Figaro, at Kalbia. He will give you the Durandal Sword after he is defeated, before dying. 12-Valley of Kastro Find and recruit Rauny the Muse at a western temple. Have Rauny confront Ares at Tash Kent. Locate the Chaos Gate in the southern mountain ranges. 13-Balmorian Ruins Obtain the Bell of Light at Kalyao. Use the Bell of Light on the statue of Saradin at the temple near Balmoa. Saradin will come back to life, and ask him to join you. Have Saradin confront his former friend Albeleo at Balmoa. Locate the Chaos Gate in the far northeast. 14-Muspelm Confront and break the spell on Slust the Dragoon, and recruit him. Find the Chaos Gate on a nearby island. Obtain the Peridot Zodiac Stone at a temple in this area. 15-Organa Fight and break the spell on Fenril the Dragoon, and ask her for help. Find the Chaos Gate on this island. Obtain the Ginger Cake from the crazy monk at the hidden SE temple. 16-The City of Malano Recruit Prince Tristan ("General" class) at Bel Chel by having the Key of Destiny or a high Reputation, and taking your Lord there. Have Rauny or Prince Tristan confront Baron Apros at Malano. Obtain the Ruby Zodiac Stone at the city of Sanbelnia. 17-The Tundra Have Yushis confront her older sister Mizal at Valhalla. Receive the Turquoise Zodiac Stone at a temple on central north island. 18-Antalia Recruit Yushis the Cherubim at hidden temple in the central mountains. Find the Chaos Gate on the far western island. 19-Antanjyl Confront Galf and destroy him and send him back to the Underworld. Do NOT give him the Brunhild Sword and do NOT let him join you. If your Reputation and/or Alignment is high anyway, he won't even ask. 20-Shangrila Confront Prince Gares with Prince Tristan at Shangrila. Recruit General Debonair at Shangrila after defeating Gares. You must also have Norn in your army for this to happen. Obtain the Sapphire Zodiac Stone at a temple here. Take the Olden Orb, Gem of Doun, and the Gem of Truth to Shangrila to speak with the Goddess of Justice, and receive the Tablet of Yaru. The Tablet allows you to collect the Zodiac Stones. 21-Fort Alamoot Find the Chaos Gate in the southwestern island with the blocking walls. 22-Shiguld Fight and break the spell on Fogel the Dragoon, and have him join you. Obtain the Diamond Zodiac Stone in this stage. 23-Dalmuhd Desert Obtain the Gem of Doun by taking the Mercury to Aliabard, hidden in the northeast desert. Visit a nearby temple here to obtain the Amethyst Zodiac Stone. 24-The Ryhan Sea Obtain the Gem of Truth by taking the Gem of Doun and the Olden Orb to Ramoto. Obtain the Topaz at a nearby temple. 25-Fort Shulamana Confront General Previa with Prince Tristan, and return to Shulamana after the battle to receive the Mystic Armband. 26-Shrine of Kulyn Confront and defeat General Luvalon honorably to receive the Bizen Sword, and return to Kulyn after the fight to obtain the Holy Grail. 27-The City of Xanadu Have Rauny confront and defeat her father, Overlord Hikashi, at Xanadu. Avoid liberating temples and cities until after the defeat of Hikashi, the people hate you here in the home of the Empire, and you will suffer massive reputation penalties for liberating Imperial cities/temples. 28-Zeteginea Visit Azuzau and speak with Sir Gawain, a Zeteginean Paladin. Beat the crap out of all of Prince Gares's clones (close to 15 or so!) Visit the hidden NE temple and speak with the REAL Prince Gares. Confront Empress Endora with Debonair at the Zeteginean castle. 29-Temple Shalina Confront the real Prince Gares with Debonair at Shalina. Confront Sage Rashidi with Saradin, Yushis, or the Lord (yourself) at Shalina. Prepare for an extremely difficult fight with Diablo, the God of the Underworld, at Shalina, and destroy him to end and win the game. 30-Dragon's Heaven This is a special secret stage and is purely meant for fun. Enjoy. Imperial Specific Character Classes- -These are character classes that you will NEVER be able to receive, and don't even ask me for ways to get them, because you just CAN'T! There is absolutely no way to get these characters, and even if by some crazy rare chance that you somehow get a neutral Dark Prince (Prince Gares) to join you in a neutral encounter--which I have SEEN happen in the Zeteginea stage on the SNES version, your game will start to glitch up and then will crash. You cannot get them anyway as there are probably no reverse angle frames of animation made for them (ie, so they move when on your side of the table in the battle screen, and that's probably why the game crashes if you get a Dark Prince Gares to join you because there are no animated or still frames of him being shown from the backside.) Almost all of them are stage bosses or the enemy unit encounter (in the case of Gares). Dark Prince (a huge, nasty evil knight in black armor with a huge axe) Vanity (a slender blond haired nobleman in expensive clothes n'cloaks) Gemini Twin (a huge and really buff looking guy wearing little armor) Highlander (a huge warrior in dark armor with a gigantic broadsword) Black Queen (a very beautiful and slender blonde woman with light skin) Wiseman (a big dark-haired man in orange wizard robes and armor) Diablo (evil demon itself, I can't see an evil god on your side anyway) List of Special Characters who can join you- This is a list of the special characters who can join you in this game. Getting them is certainly worth it, as their abilities are super inflated compared to a normal member of the similar class. They often drag along really good bodyguards, who are usually better than their own class as well (ie, when you get Fenril to join you, she drags along a Gold Dragon that is MUCH stronger than the other average Gold Dragon you would recruit or raise from a lower class.) Getting these characters not only will enhance your ending, but practically all of them can be quite nasty in combat. 1-Warren (Wizard)- The boss of the first stage, the Castle of Warren. Defeat him and he will join you. If you cannot beat Warren, then turn the game console off RIGHT NOW you complete boob, as you are truly beyond help. :) 2-Lans (Knight)- He is in the hidden NE city of Zeltenia at Castle of Warren. Simply liberate the town, and he will join you. 3-Canopus (Eagleman)- In the city of Bah'Wahl in Sharom District. Recruit him by first liberating Chang'Gah, and then talk to him at Bah'Wahl. Answer one of his questions (choosing "for freedom" seemed to anger him the least), and then liberate the hidden temple SW of the boss's castle. You will receive the Wing of Victory here from his younger sister Yulia. Return to Bah'Wahl with the wing and he will join you. 4-Gilbert (Beast Tamer)- Stage boss of Sharom District. If you have Canopus with you, confront him with his best friend, Canopus. After the fight, agree to hear his side of the story, forgive him, and Canopus and Gilbert will reconcile their differences, and he will join you. 5-Deneb (Witch)- Stage boss of Deneb's Garden. First off you must forgive her, and then she will request you get her a Golden Bough (which is bought at Diaspola). Return here with it, and she will give you the Glass Pumpkin. If you Reputation is LOW enough, she will join you as well after you complete that quest of hers. 6-Ashe (Knight)- He's imprisoned in a walled-in city in the Slums of Zenobia. Simply liberate the city and he will request to join you. 7-Lyon (Beast Tamer)- He's a mercenary for hire at one of the towns in the Slums of Zenobia. You can purchase his services for $20000, or if you can wait until the end of the stage and come back later, you can buy his talent for only $5000. 8-Aisha (Shaman)- At a hidden temple in Island Avalon. You must have a high Reputation for her to join you. She drags along two Mermaids, who aren't too shabby, and are very close to turning into Nixies. 9-Norn (Shaman)- She's the stage boss of Diaspola. You must have a high Reputation, and after defeating her, refuse to kill her, and ask her to join you. Stating that General Debonair (her fiancee) is alive will help as well. Norn also drags along two Titans for the trip! Wowie- zowie! 10-Rauny (Muse)- At a temple in the Valley of Kastro. You must have a high Reputation for her to join you. 11-Saradin (Mage)- Saradin has been petrified at the Balmorian Ruins, and is a statue at the north temple near Balmoa (Albeleo's castle). The easiest (but longest) way to get him is you must first liberate all the towns and temples (including hidden ones) EXCEPT Balmoa (the boss's castle) and Kalyao (a hidden city in the southwest.) Then liberate Kalyao, and if you have a high Reputation and the Star of Heroes, they will give you the Bell of Light. Return to the northern temple, and use the bell on the statue. Saradin will then awaken and request to join you. 12-Slust (Dragoon)- The stage boss of Muspelm. Fight him and defeat him, and if your Reputation, Alignment, and Charisma are high, and you have the Star of Heroes, he will join you. 13-Fenril (Dragoon)- The stage boss of Organa. The same requirements to get Slust apply to her as well. 14-Tristan (General)- Prince Tristan is in the city of Bel Chel in the City of Malano stage. You must either have the Key of Destiny (obtained with a high Reputation at Kal Robs in Slums of Zenobia) or a high Reputation, and you must take your Lord personally there for him to join your ranks. Tristan is a powerful fighter, and check out the things he can recruit! 15-Yushis (Cherubim)- She is at a hidden temple in Antalia. You must have a high Reputation, Alignment, and Charisma for her to join you. 16-Debonair (General)- After you defeated him at Zenobia, he questioned Empress Endora's actions, and is now being imprisoned at Shangrila. You MUST have Norn (his fiancee) in your army, and a high Reputation for him to join you. Debonair is a VERY good character, not only is he strong, but check out the stuff he can recruit! 17-Galf (Devil)- The stage boss of Antanjyl. You must have an extremely LOW Reputation, low Alignment, and you must give him the holy Brunhild Sword (UH...) after defeating him for him to join you. Nasty little guy, he is... :) 18-Fogel (Dragoon)- The last (and probably the mightiest) special character in the game. He is the stage boss of Shiguld, and recruiting him meets the same requirements as those to get Slust and Fenril. Not only is he a nasty fighter, but check out what he can recruit! Level Up, Alignment, and Charisma Clarification- I) Level Up clarification- Characters gain experience points (XP) by defeating enemies. The amount gained/lost varies depending on these factors- 1) Enemy level compared to the level of your character. You will gain more if the enemy character is stronger than you, you gain less if the enemy is weaker than you. 2) Type of enemy character killed. For instance, killing a Mage is worth more than killing a Wizard. 3) Participating in a battle earns you 1 experience point, no matter the outcome. Win or lose, you will still get at least 1 XP. 4) If one of your characters is killed in action, their "To next level" experience counter is set back to 100 (ie, the very start to a new level) the next time they are revived. In effect, you pay a penalty by starting over because they were killed in battle. Experience is gained by ALL members of the unit, not just by the character who kills another. Ie, a member of your squad WITNESSING the death of an enemy character will gain experience points. Upon reaching 100 points, your character will advance a level (and will gain appropriate statline bonuses depending on their class when they leveled up) and then will start over to gain a new level with the counter reset at 100. VERY IMPORTANT NOTE-- You CANNOT gain more than one level per battle, and any "left-over" XP does **NOT** carry over towards your next level. I'll explain this below- IE, say if you were 30 XP away from level 7, but yet you slaughtered 60 XP of stuff, you will gain a level and go to level 8, but the 30 "left- over" points ***DO NOT CARRY OVER*** to your counter to reach level 9. You will start again with 100 XP needed to gain another level to level 9, and **NOT** 70 XP. This is VERY important, and is VERY different from almost all other RPGs and strategy games out there, so remember this clearly when destroying enemy units. In effect, this is a very neat and clever way by the game designers to make this game more difficult and challenging for you. II) Alignment clarification- You may wonder how Alignment works in this game. Alignment, in essensce, is how good or evil a person is. A good-hearted person has a very high alignment. An evil-hearted person has a very low alignment. Many reasons in the reviews of this game I have seen in some places is people become so frustrated with it because their characters Alignments are outta whack and they cannot change class. Like you have a Level 15 Knight who has an Alignment of 17 and a Charisma of 21, and thus, he can't turn into a Paladin, because, well, he's evil. :) Alignment is actually a VERY simple formula, and requires no complex knowledge of algorhythms or numbers to figure it out. I figured it out myself easily the **SECOND** time I played through the game. Alignment, as may be perceived, does NOT just affect your Reputation meter when you liberate towns and cities! Some complain because they say the "Alignment" system is unrealistic (in fact, it's NOT!) and they can't figure out why their Knight is so evil and can't turn into a Paladin. I can't believe these people couldn't figure this out. There are no complex/erronious numbers or equations involved, any average basic educated person should be able to easily figure this out. I'll explain below. :) Ogre Battle is one of the very few games that takes this IMPORTANT "Karma Characteristic" into account. It is a rare game where you cannot just run around slaughtering enemies left and right and expect to become the champion of the people simply because you whooped a bunch of monsters' @$$es. Not that Final Fantasy or other RPG games like this suck, they are good, but not as involving as this game is. Well, enough with my brief opinion, here we go- It is a very realistic system. Here's how it works- Alignment is a 0-100 measure of how "good" or "evil" you are, and can be based roughly (on my estimate) by this scale (you may have seen this before earlier in my FAQ)- 0-10: Evil 11-20: Very Chaotic 21-34: Chaotic 35-49: Neutral-Chaotic 50-60: Neutral 61-70: Neutral-Lawful 71-80: Lawful 81-90: Very Lawful 91-100: Saintly The characters in your armies' alignment is affected by these factors- 1) Starting character class. If you recruit a brand-new Fighter (ie, from the "Replenish Character" command by the unit leader in a city) his Charisma and Alignment will be around 50 because he's Neutral and just starting off to make a name for himself. If you recruit an Imp, his Charisma and Alignment will start much lower because he's evil, see? If you recruit a Cleric, her charisma and alignment will be naturally high to start because she's a priest/holy warrior. Got it? 2) WHO YOUR CHARACTER KILLS! This is the HUGEST part of alignment. Your alignment will rise and fall depending on these conditions- 1) Level of your character compared to the level of the enemy character that you killed. 2) Alignment of your character compared to the enemy character's alignment that you killed. In essence, it is who is seen as "the good guy" and who is "the bad guy". It works this way- Your character will GAIN alignment if he (or she or it, but "he" refers to ALL characters in general) kills an enemy character that is higher in levels than he is. In essence, your character is seen as "the underdog" and is taking on a person/monster more powerful than he is. So, you are seen as "the good guy" here because you are being honorable and challenging someone mightier than you to a fight, and besting them. Your character will also GAIN alignment if he slays an opponent who has lesser Alignment points than he has. In effect you are playing the role of "good guy" by vanquishing an evil person from the world. So, in essence, your Knight gains alignment by ridding the people of that foul Imperial Werewolf (such as Sirius...) that plagued the countryside. Your character will LOSE alignment by killing someone who has HIGHER Alignment points than he has. You are "the bad guy" because you are killing someone who is generally good-hearted. Your character will LOSE alignment by picking on someone who is weaker than he is. This represents you killing enemies who are LOWER in levels than your character is. You are seen as "the bad guy" here because you are being a bully and picking on someone who is not a difficult fight. NOTE- This is not "black and white", and does have some acceptable gray areas to it. IE, for gaining alignment, if you kill someone who is higher in level than you, you gain alignment. You will gain MORE alignment for each level the enemy is stronger than you. So you gain more points killing someone four levels above you than you do 2 levels above you. If you kill someone who is equal or a level or two lower than your level, your alignment will not change. If you kill someone who's level is three or more levels less than you, you will lose alignment. Works the same way as gaining- you will lose more Ali depending on HOW MUCH weaker the enemy is compared to you. These effects are COMPOUNDED together, as well, so, if you do it right, you can really SOAR your alignment by having high Alignment to begin with, and then mauling a Phantom who is two levels higher than you and has much less Alignment. You can lose Alignment just as easily by sending your low ALI Level 10 Wizard against a high ALI Level 8 Cleric and killing her. See? It's not that hard. If you are REALLY clever you can manipulate this to your advantage (example- letting your Level 15 Mages "whittle down" a level 12 Demon to near death, and then letting your level 10 Knight finish him off so he can gain Alignment and Charisma. If you set your "Battle Tactics" carefully you CAN do it. You actually DO control more over your troops in combat than you may THINK you do.) Note that the changing Alignment applies ONLY to the character that killed the enemy character. A person witnessing an enemy dying at the hands of an ally does not gain or lose alignment because of it. III) Charisma clarification- Charisma works almost the same way as alignment, you gain charisma in pretty much the same way. Charisma is defined as your "spunk" and your appearances and conduct towards others. A highly charismatic person is easily likable, the "toast of the town", the "hit of the party", and works well with others. A person with low charisma is seen as a "douchebag" or "spaz" to others, and isn't likable. It's a little more of a relaxed system, though. Pretty much having a lower level character of yours kill a higher level enemy character will help raise your character's charisma. And on a final note- HIGH CHARISMA in this game (and most RPGs) is a VERY GOOD THING, ***REGARDLESS*** of what path (good, evil, or neutral) you are pursuing with a character. It is ALWAYS an advantage to be more liked and more charismatic. There is pretty much no bad thing to having high charisma. Being a "likable bad guy" does have its good perks. You may be chaotic, but at least you're not a douchebag about it. :) A high charisma will help raise/lower your character's alignment to fit his proper class. In essence, charisma helps raise/lower your alignment faster and better when you defeat someone. Experiement to see what it does, and note that almost all of the VERY POWERFUL character classes (good AND evil) in this game require HIGH charisma to obtain. As a side note, it is CONSIDERABLY more difficult to gain Alignment when your own Alignment is very low. If your character EVER hits "0 Alignment" (rock bottom), than if you ever want to get it back up again, you will have to kill some VERY high level characters higher than you to remedy it. Consequently, it's also kinda hard (but not as difficult) to lose Alignment if your Alignment is really high. In general, though, I tend to like to shoot for "light" (ie, High Alignment) units and characters because in general "good" character classes are better fighters than evil classes. This also applies to Charisma, the less liked you are, the harder it is to up it. But what do you do if your Samurais and Knights (whom you want to be good) suddenly see an enemy unit of Angels and Shamans (high Ali) coming at them? If you kill them, Mr. Samurai's Alignment goes down, and we don't want that, do we? Because he wants to eventually be a Samurai Master, right? Well, the answer is simple- don't fight them. :) Retreat your unit be moving it away/using 7-League-Boots/Dinner Bell, etc, and instead, send in your Mage and his two Tiamats and give the goody-two-shoe enemy unit a mugging they won't forget. Your Mage and his Tiamats won't care about losing alignment one bit. :) This works to your advantage- you can send "evil" units to wipe out "good" enemy units that you don't want your Neutral or "lesser" (as in "lesser" meaning lower Alignment and Charisma) Good units to fight. Or if you REALLY have to fight a good unit like this with a "lesser good" or "neutral" unit of your own, set your tactics to "Leader" and just try and kill the unit leader, and then let the enemy unit run away from you back to Imperial base. It is the only real "honorable" way to try and do it, as killing just one person in the enemy unit and then having it run away from you, and you suffering a small penalty in Alignment is MUCH better than you mauling the entire unit stack and having someone's Alignment go down the toilet, of who's Alignment you do not WANT to go down the toilet. But don't worry. If you follow the stages in general order (1,2,3,etc) then the enemy units in general will be higher in level to start than most of your units. If you find that one of your units is more powerful than the majority of the enemy units in the stage, and you don't want your unit's Alignment or Charisma to drop, than be a good general- simply let that unit sit on the sidelines for the current stage. Deploy them again when the enemy is stronger (and have them gain even MORE Ali and Cha!) Let your weaker units get more action (and killing stronger opponents nets more XP, by the way!!!) If you also find that one of your units levels up in the field and is at or exceeds the enemy units' levels, then it's, in general, a good idea to pull them out of action. Dinner-Bell the unit, or whatnot, and have another unit take their place. You can do the opposite if you want to LOWER the alignment of a specific unit of yours (ie, you want that Mage, but your Level 11 Wizard is at Alignment 40 and needs to kill a few holy characters or weaklings to get it down to turn into a Mage), ie, just keep sending him at people, killing left and right, raising the levels and dropping his Ali. So just be a smart general and go about what you need to do. So there, that's the end of the level/charisma/alignment schpeel. And, if in the future you happen to have that Level 17 Knight (whom you are trying to turn into a Paladin) and who is at Alignment 10 because he killed too many people weaker than him (which you shouldn't have done as that's STUPIDITY) than either turn him into a Black Knight (or something where he's more USEFUL!) or DITCH him altogether and get a replacement. Nobody ever said you couldn't "fire" someone from your army. In fact, I do it all the time. I've fired Salamanders before who's Alignment fell too low and they couldn't become Flare Brasses, etc. If the character isn't working out, just hit the "Erase Character" icon and select the offending individual. Ka-put. Gone for good, never a worry anymore, that useless Alignment 10, Level 17 Knight is no more. Though, amusingly, an Imperial character may show up later with the same name. I like to think of that person then as a "disgruntled employee" who joined the Empire because I got rid of him. :) There, that's the end of that part! Encyclopedia of Magic and Special Attacks- -Within this area lies the explanations of all the sorts of special attacks in Ogre Battle. Key- (Name of the Attack) (Element/Special Ability) (What targets it hits) (Who uses it) Melee Attacks- 1)Hand to Hand Combat Attack (varies in MANY names) -Physical, non-magical -One enemy -Nearly ALL characters in this game have some form of melee attack -This can be changed by equipping certain armors and weapons (or by using Fire Bolt or Ice Bolt with the appropriate Giant), and the color change in the strike indicates what type of element is being added: Yellow/Orange= Physical Blue= Cold Red= Fire Green= White (Holy) Dark Gray= Black (Unholy) Purple= Electrical -Therefore, for example, a Knight equipped with a Notos sword will perform cold attacks. A Fighter equipped with a Rune Axe will perform white attacks, and so on. Black Magic- 1)Fireball (big ball of fire hits target) -Fire, magical -One enemy -Wizard, Black Knight, Sorcerer 2)Tornado (wind storm slashes target's skin) -Physical, magical -One enemy -Wizard, Sorcerer 3)Ice Field (orb of ice engulfs target) -Cold, magical -One enemy -Wizard, Sorcerer, Dragon Master 4)Lightning Bolt (electrical bolt slams enemy) -Electrical, magical -One enemy -Wizard, Sorcerer, Valkyrie 5)Nightmare (evil spirit energy attacks enemy) -Black, magical -One enemy -Wizard, Sorcerer, Imp, Demon, Ghost, Phantom 6)Fire Wall (flaming wall of fire hits enemies) -Fire, magical -All enemies -Mage, Sorcerer, Lich 7)Ice Storm (whirlpool of swirling ice and water slashes enemies) -Cold, magical -All enemies -Mage, Sorcerer, Lich, Nixie 8)Phantom (evil poltergeist spirit energy engulfs enemies) -Black, magical -All enemies -Mage, Sorcerer, Lich, Lord (Chaotic) 9)Thunder Flare (lightning storm smashes enemies) -Electrical, magical -All enemies -Mage, Sorcerer, Lich, Muse, Lord (Neutral-Chaotic) 10)Acid Cloud (strong sulfuric acid gas corrodes tissue and armor) -Physical, magical -All enemies -Mage, Sorcerer, Lich, Doll Mage, Enchanter 11)Meteor (huge meteorite drops from the sky onto enemies) -Black, magical -All enemies -Devil 12)Wind Storm (waves of fierce wind slash skin) -Physical, magical -All enemies -Griffon 13)Wind Shot (sonic waves/fierce winds cause targets to disintegrate) -Physical, magical -All enemies -Titan 14)Blizzard (ice crystals and snow hit enemy) -Cold, magical -One enemy -Mermaid 15)Thunder Arrow (electrical bolt zaps enemy) -Electrical, magical -One enemy -Eagleman 16)Firestorm (explosion of oxygen creates fierce firestorm on target) -Fire, magical -One enemy -Ravenman 17)Stun Cloud (paralyzes enemies) -Non-elemental, magical (does not damage targets) -All enemies- paralyzes them in place, disabling them from moving and attacking. Striking a paralyzed target with magic or physical attacks MAY break the hold on them. -Witch 18)Mesmerize (paralyzes an enemy) -Non-elemental, magical (does not damage targets) -One enemy- works like Stun Cloud, only this hits one target -Cerberus 19)Charm (hypnotizes an enemy to do your bidding) -Non-elemental, magical (does not damage targets) -One enemy- confuses the target and makes him attack his friends -Vampire 20)Life Suck (drains spiritual life force from a target) -Physical, non-magical -One enemy- drains health of the target and gives it to you -Vampire White Magic- (white magic is less available than Black Magic, but rest assured that the all-hit power spells of white magic are indeed much more powerful than pretty much all black magic spells. Note that it pays to be a good person in this game...) ***NOTE- **ALL** White spells/attacks will INSTANTLY destroy an undead character (Skeleton/Wraith/Ghost/Phantom) upon contact. To have your characters use "healing" white magic on undead, set your battle tactics to anything BESIDES "Strong" before they cast the spell. If it is set to "Strong", they will heal your own characters normally instead of attacking all the undead characters. Note that a spell such as "Healing" that normally heals one ally will attack ALL undead enemies. And as a final word, undead can ONLY be destroyed by white attacks. They are completely invulnerable against everything else. 1)Banish (rings of pure energy destroy evil will) -White, magical -One enemy -Angel, Cherubim, Lord (Lawful) 2)Halo (ring of holy energy from angel halo strikes target) -White, non-magical -One enemy -Angel, Cherubim, Seraphim 3)Jihad (mystical purity zaps enemies and erases evil spirits) -White, magical -All enemy -Seraphim 4)Stardust (phantasmal space energy hits target) -White, non-magical -One enemy -Princess 5)Starlight (rains radiant energy of stars and the sun on enemies) -White, magical -All enemies -Princess 6)Healing (restores health to an ally) -White, magical -One ally/all undead enemies -Cleric, Shaman, Paladin 7)X-Healing (restores health to all allies) -White, magical -All allies/all undead enemies -Monk 8)Magic Missile (white fireballs of mystic energy slam the enemy) -White, magical -All enemies -Sylph 9)Kiss (give a flirting sexy kiss to your ally) -Non-magical, non-attack (cannot destroy undead) -One ally- raises his attack and defense for the duration of the battle -Faerie, Pixie Ninjutsu Magic- (HAI-YAHH! USE 'YER MAD NINJA SKILLZ, BRO'!) 1)Katon (blows a mystical fireball/lava wave at the enemy's feet) -Fire, magical -One enemy/all enemies -Ninja (one enemy), Ninja Master (all enemies) 2)Suiton (cold rainstorm/tsunami wave hits enemy) -Cold, magical -One enemy/all enemies -Ninja (one enemy), Ninja Master (all enemies) 3)Ikazuchi (thunderbolt/lightning storm hits enemies) -Electrical, magical -One enemy/all enemies -Ninja (one enemy), Ninja Master (all enemies) Warrior's Code Lore- (HAI-CHAH! I GOT THE SUPER HIDDEN SKILLZ!) 1)Sonic Strike (sacrifices your own spiritual power to strike a mortal blow upon the enemy) -Physical, non-magical -One enemy (heavily damages the target, you take some damage in return) -Samurai, Samurai Master, Lord (Neutral), Dragoon, General (Tristan) 2)Sonic Blade (inner secret power of the warrior's code unleashed) -Physical, non-magical -One enemy (heavily damages enemy target, does NOT take your own HP) -General (Debonair) -Stage Boss Attacks- General Luvalon (Extinction), General Figaro (Down Claws), and the Gemini Twins' (Gemini Attack) would also fall into this category. Breath/Monster/Special Magic- 1)Fire Breath (breathes a fireball from the lungs at the enemy) -Fire, non-magical -One enemy -Dragon, Red Dragon, Salamander, Flare Brass, Cerberus, Hellhound, Wyvern 2)Ice Breath (breathes cold air from the lungs at enemy) -Cold, non-magical -One enemy -Silver Dragon, Gold Dragon, Platinum Dragon 3)Acid Breath (vomits corrosive stomach acid on enemies) -Physical, non-magical -One enemy -Black Dragon, Tiamat, Zombie Dragon 4)Super Nova (breathes out a concussive and intense explosion) -Fire, magical -All enemies -Flare Brass 5)Ice Cloud (cold air freezes target's blood and bodily fluids) -Cold, magical -All enemies -Platinum Dragon, Lord (Lawful) 6)Toxic Breath (belches noxious stomach gas onto target) -Black, non-magical -One enemy -Zombie Dragon 7)Death Cloud (changes enemy's breathing air into poisonous vapors) -Black, magical -One enemy -Lord (Chaotic) 8)Evil Ring (summons evil spirit energy upon the enemy) -Black, magical -All enemies -Tiamat 9)Pumpkin (gigantic jack-o-lantern drops onto an enemy) -Non-elemental, magical -One enemy (damage is calculated as halving the target's current HP) -Pumpkinhead, Halloween 10)Maelstrom (huge whirlpool swallows up enemies) -Physical, magical -All enemeies -Kraken (this attack can ONLY be performed while on water) 11)Petrify (cloud of gas changes character into a stone statue) -Physical, magical -One enemy (petrifies them so they cannot attack for rest of battle) -Cockatrice ***NOTE- There is apparently a BIG glitch in the PSX version with Petrify- this spell will hardly, if ever, hit an enemy. (That does it for the Encyclopedia of Magic and Special Attacks!) Battle Tactics/Lord System Subscreen- -Ogre Battle has a different battle system compared to other games. When you are in battle, you are limited in manipulating certain commands that influence what your troopers attack. Some complain that this is unrealistic and that they cannot completely control their troops in battle like Final Fantasy games or whatnot (ie, they complain as they say that "I lack the control to tell my Samurai to attack THIS specific target.") In fact, this is a VERY realistic system. You are the general, commanding your troops from a very long distance. Your troops DO NOT possess the "god-like" knowledge that you do, as the general, the gamer, who can see the entire world/area map and whatnot. They cannot, they are in the field fighting the enemy in the middle of battle. Swirling and wild combat seriously impairs people's judgements often, so be wary that your troops may not ALWAYS respond correctly to your commands or perform EXACTLY what you want them to do. That is life, and that is how combat in the real world works. This is also medieval combat, so there are no radios or comm-links for you to talk to your unit's leaders, so don't expect that ability. There aren't even magical devices that enable this. :) Due to the fact that your troops lack this "god-like" knowledge, they will act in general on their own accord, and will decide what is best for the combat. You CAN set the tactics to make them in general attack certain things, but even then, your control is limited. Hitting the the X button in battle (forget what it is on SNES) will pause the battle AFTER the next creature's attack and bring up a menu of options for you, listing: Tarot Card, Tactics, Retreat, and Animation. First, you CAN change your Tactics setting and control in general what your troops will do. There are four settings: Tactics- -Tactics are essential to cause not only raw damage to the enemy unit, but to also kill enemy characters. If you do not kill the entire enemy unit (and they don't kill you), then the winner of the combat is determined by who caused the most damage, and the losing unit retreats. Should the combat end in a draw (VERY rare, but I have done it!) BOTH sides will retreat away from each other. Winning combats is important, as if you are defending a city or fighting on terrain your unit likes, you will have added attack and defense bonuses. 1) "BEST"- "Best" in essence, is assigning your unit the task of attacking characters with the most appropriate attacks/targets to CAUSE THE MOST DAMAGE POSSIBLE. Spell casters like Magi who can cast multiple element spells will therefore pick an elemental spell that will damage the enemy as a WHOLE the best. Hand to hand attacks in general will be aimed at targets to rack up pure damage points. If there are two Imperial Knights in front of your Ninja, and one Knight has 10 HP left (and could be slain in the next attack) but the other next to him has 56 HP left, your Ninja will most likely attack the one with 56 HP, to cause more damage (note that when you do enough damage to kill a character in this game, it will do the number of HP they have left, IE, if you kill that 10 HP Knight in one blow, the attack will do 10 damage. This is how "Best" tactic works. 2) "STRONG"- "Strong" defines your tactic of having your characters try and attack the target with the MOST HP. I generally have my tactic set to this usually for most of my units. If there are multiple characters in the enemy unit, and your all-hit Mage is choosing which spell to cast, he will cast a spell that will damage the STRONGEST character the most. Note that if you are fighting UNDEAD characters, having your tactics set to this tactic will cause your healers to NOT attack the undead with their magic, and heal your allies instead. Keep this in mind. 3) "LEADER"- Self-explanatory. Your unit will attempt to strike the enemy unit's leader. All magical attacks from your creatures will be purely centered on hurting the enemy unit leader the most. 4) "WEAK"- The opposite of "STRONG". You will attempt to attack the target with the LEAST Hit Points in the enemy unit. A decent tactic to use if you want to "pick on" somebody in the enemy unit, and kill them quickly. ***NOTE- You CAN change your fighting tactics in the MIDDLE of battle!! If you are smart, you can use this to your advantage, and adequately guide your troops in the fight! Know that you actually DO control more power over your troops in combat than you may THINK you do! You just have to be smart about it, and all I can say is that you have to get experience in doing this yourself. Magical attacks are pretty much ranged and can strike ANYONE, so if you set your tactics right your Wizards and whatnot can pretty much whack what you want them to, but the real puzzle is hand to hand attacks. Your physical attacks may not always land where you want them to go. This is normal. Remember that your characters will always try to attack in the way you have your tactics set, but there are certain things that can stop your character from damaging what you want him or her to. Here are some: 1)The desired target is in the back row and is being blocked by creatures in the front row. -In order for you to physically attack the back row, you must destroy everything in the front row first. This is fundamental battle tactics, and the enemy will also use this to their advantage. There could be a Zombie Dragon or something in the front to be a big "meat shield" to protect a more vulnerable Lich in the back row, for example. There are very rare exceptions to being able to hit the back row if there is still something left in the front row, however, but they are extremely few and VERY far in between, usually involving a small creature in the back on the far left, and a small creature in the front row on the extreme right, etc. 2)The desired target is being blocked by a larger creature. -For instance, say your Samurai Master is on the far side of your left front row, and you want him to hit an enemy Muse on the far right of the enemy back row, but there is a Zombie Dragon on the left in the back row. Your Samurai Master will attack Mr. Zombie Dragon instead, on account your Samurai Master cannot reach the Muse because the Zombie Dragon is a very large target and takes up two squares (the left and the center.) This is a key advantage to using a large target in this game, as they can block attackers from reaching other units. This is a big upside to large characters on account of the handicap they inflict because they take up two spots in the unit. 3)Some of your own allied creatures are blocking you from striking an enemy target. -This happens all the time. Unlike other RPGs and military strategy games, your own friends can block your path or line of sight to attacking the enemy. In a game like Starcraft (a computer game) and Warhammer 40K (a board game) your Space Marines can shoot over the heads and even THROUGH your own allies without hitting them, but this is not the case in this game. You may want your far left front row Paladin to attack the enemy Monk on the far right front row, but he can't because you have an allied Paladin in the center front row, and one on the right front row. Thus, your own troops are blocking your far left Paladin from striking the far right. However, sometimes flying creatures can fly over the heads of your friends, and still strike the target you want them to. A little advantage for flying creatures like Griffons, Ghosts, Imps, Hawkmen, and so on. ***However, do note that all of these range restrictions are moot points if there is only one enemy left in the unit, etc. Due to the fact that there is only ONE enemy character left in the unit, none of your characters will sit around and miss a turn or whatnot, even if friends might normally block their movement. You will just have to see for yourself what these restrictions can do to you, and just make the best of things. Tarot Card- This enables your Lord to play a Tarot Card in the battle to give your unit a little bit of a "boost" or an "edge" over the Imperial unit by attacking the enemy or giving your characters a temporary boost in agility, defense, etc. The effects of Tarot Cards will be discussed in a lower section. You can only play one Tarot Card at a time with this command. If you wish to use another card, you must hit the X button again later after resuming combat. Retreat- This fight isn't going very well for you? One of your characters is about to level up, but is at the verge of dying? Then, don't stay in the fight anymore. Retreat and run away to fight again later. Do keep this in mind, though- Running away frequently can be bad, as each time you run away, ALL of the characters in your unit will lose 1 Charisma point. Running away every so often isn't bad, but don't do it REPEATEDLY, or you will find your Charisma in the toilet as the people will see you as a coward. :) Animation- All this simply does is turn the graphical animations of movement and attacks on or off. Personally I like to leave it on, it makes the combat more lively and fun to watch. Effects and Uses of Tarot Cards- Key- (Name of Tarot Card) (Description) (Bonus Effects when drawn after liberating city or temple) (Effect when used in battle) (Commentary) -Tarot Cards are earned by either liberating cities/temples and drawing them (where you get their bonus effect immediately, and then the option to keep the card for battle use, or discard it and not keep it for battle use) or by using the "Joker Tarot" item (where you will randomly draw a card and be asked if you want to keep it for battle or not. You do NOT get the bonus effects of the card when drawn this way, but you may keep it for battle purposes.) 1) Magician A wizard holding a staff in a flaming background Characters' Intelligence +1 Causes fire damage on all enemy units (based on Lord's INT) -The Magician card is a fairly good card to draw after liberating cities, and its effects in battle aren't that bad. Almost all of the magical7 attacks are based on the Lord's intelligence, just so you know, and they also calculate your Lord's alignment as well (ie, if you are lawful, your Magician or Hermit cards, etc, will cause more damage in the day and less in the night.) The Magician card is an ideal card to use against Ice Giants and Nixies, things like that. Magician is drawn fairly commonly. 2) Priestess A woman with a bishop's cap on her head, wearing white robes, sitting on a throne and bowing her head down in prayer. Characters' Alignment +1 Heals 50 HP to all characters in your unit -The Priestess card, in my opinion, isn't that good of a card. Drawing it isn't bad, as boosting the alignment of all the characters in that unit by +1 isn't bad, but the combat effect is near worthless after your characters reach around level 10 or so and have around 130+ HP. Still, though, it can be useful to keep to save someone heavily wounded from certain death at the hands of the enemy. The Priestess card is drawn fairly common. 3) Empress A very beautiful queen sitting on a throne with a tiara on her head, wearing red robes, and surrounded by a cloak of feathers. Characters' Charisma +1 Heals all characters in your unit to FULL Hit Points -The Empress card is a VERY good card to draw, and she shines the best when used in battle. If your unit gets heavily damaged, toss this card on the table to be brought back to full health! She is rare to draw, though, but, it is an outstanding card (and the illustration is VERY pretty, too!) 4) Emperor A shaggy bearded king wearing blue robes, standing upright, with both hands resting on a long scepter. Characters' Charisma +2 Gives all characters in your unit +1 Attack -The Emperor card, in my opinion, is by FAR the BEST card to use in combat! Drawing him is really good too, but the kicker is what he does in combat! Playing the Emperor card will give all the members of your unit an additional attack!!! And, if you have more than one Emperor card, if you really need (or want) to, you can use another and get another attack! He's awesome! The Emperor card is rare to draw, so definitely take it if you do draw it from the deck! 5) Chariot It's the Norse God Loki wearing a helmet and carrying a HUGE super sledgehammer! Smacky-hitty-poundy hammer! :) Characters' Strength +2 Summons Loki to attack all the enemies (based on Lord's STR) -Chariot is a REALLY good card to draw, but he's not that good in combat. Enemy characters with high strength will just laugh at the damage done to them, and in general the Lord doesn't gain a whole lot of strength per level up (unless you are Neutral, in which Chariot can dish out a LOT of damage.) Chariot is drawn on an average base, but he appears less than common cards. 6) Strength A picture of a woman scratching the head and mane of a big lion. Characters' Strength +1 Ups the defensive power of your allies in battle -Strength, in my opinion, is a pretty worthless combat card. It doesn't really help you a whole lot. The draw bonus isn't phenominal either, but better than nothing. If you draw this card, I would suggest not keeping it. Strength is VERY common. 7) Death A picture of the grim reaper skeleton with a huge scythe. Reputation Meter -2 Casts "Death" spell on enemy unit in battle -Death is a horrible card!!!! You don't want to draw him, either! Not only does this lower your reputation by two (ouch!), but the spell in battle will ONLY kill enemies that are reduced to less than 50% of their health. Plus, ALL the experience of characters slain this way goes to your Lord, and NOT your unit. I personally keep my Lord weak (people trust you more when you are weaker than your troops you command!) and killing creatures with the Lord or with Tarot Cards will cause all the points to go to him/her and cause him/her to level up very quickly. I never use the Death card. Discard it if you get it. Unfortunately, Death shows up fairly common. 8) Fool A picture of a hobo in ragged clothes toting a bandana sack on a pole. Characters' Luck +1 Causes all enemies except the unit leader to flee from the combat. -The Fool is a great card to draw (besides a Lucky Charm item, it's the only way to raise your Luck!) and his ability to cause enemies to run away is pretty useful! This is an AWESOME card to use against the stage boss, and get rid of his bodyguards! Or, if you feel like you may lose an upcoming fight with the enemy, get rid of everyone in the enemy unit but the leader, and you will probably easily win the fight! The Fool is fairly rare to draw. 9) Moon A picture of a beautiful woman soaring on a moonbeam through the night. Changes the time of day to midnight Inverts the front row and back rows of the enemy unit. Back row characters move to the front, and front row characters move to the back. -The Moon card doesn't affect your unit directly at all, it just turns the time of the day to 12:00 AM. This is a really interesting card to use in combat, you can use it on enemy units to screw over their formation and mess them up by bringing Witches, Magi, and Clerics to the front, and throwing Ninjas and Paladins (and other good front- liners) in the back row! Note that the enemy unit characters will still attack the same number of times from their STARTING position before the Moon card was used, but the TYPE of attack will change (ie, if you move a Phantom from the back row to the front, he will attack three times, but it will be Curse, and not Nightmare.) The Moon card does have its clever uses, and I generally keep one or two handy for just such an occasion where I can really SCREW UP the enemy formation and move things like Liches and Sorcerers in the front row, and Ninjas to the back, making the fight a lot easier. Moon is drawn every so often, on an average basis. 10) Sun A picture of a near-naked muscular man and near-naked athletic-looking woman standing back to back (the woman faces towards you) and embracing the strength of the sun by reaching their arms toward it. Changes time of day to high noon Damages ALL characters on the battlefield, hurts those with low ALI heavily, and those with high ALI less. This will also slay undead characters instantly. -Sun is a terrible card to draw. The near naked woman looks really cute, but this is a family game, and of course she's just in what looks like a really revealing swimsuit. Changing the time to noon doesn't affect your units directly, but I hate this card's combat effects on account is hurts EVERYONE. I rarely use this card. Sun is drawn fairly common, unfortunately. This card is exactly like the "Crusader" esper from Final Fantasy 3(6), so make sure your unit has HIGH Alignment when you use it, or you will receive a TON of damage! 11) Hermit A picture of Merlin the wizard with a huge long white beard. Characters' Intelligence +2 Attacks the enemies with lightning (based on your Lord's INT) -The Hermit is a decent attack card, and attacks the enemy with an electrical blast. He is drawn on a fairly average basis, but ironically, a little more frequently than the Magician. The Bonus of the draw is better, but Hermit doesn't do as much damage as the Magician usually does. 12) Star A picture of a pretty woman standing on stars and pouring two pitchers of water onto the world. Characters' Agility +1 Increases the Agility of all allies when used in battle. -Star is a good and useful card, and helps your units hit those otherwise hard-to-hit-physically characters like Griffons, Ghosts, and Eaglemen. The bonus when drawn is really good, too. Star shows up on an average basis. 13) Lovers A picture of a naked woman and man standing back to back with their intimate spots being covered by an intertwining flowering plant and the woman's arms. Reputation Meter +2 Calls forth Eros to attempt a charm spell on the entire enemy unit, causing some/all/or none of them to start fighting each other. -What is up with all the beautiful near-naked/naked women? It's like everyone wants to draw these cards simply to look at them. :) Oh well. Lovers is a good card to draw, and the battle effect can turn the tide as if you zonk an enemy Mage or Sorcerer, things really turn ugly for the enemy fast. :) However, the charming spell hits random targets, so you may hit all, some, or NONE of the enemy at all when you use it! Lovers is relatively rare to draw. 14) Hanged Man A picture of an unfortunate man being hanged from a tree limb. Characters' Strength -1 Lowers the defensive strength of the whole enemy unit. -The Hanged Man card isn't that bad of a card, and in fact, I find it quite useful to throw at the start of a fight, so that enemy characters can suffer more damage from magical attacks. It doesn't lower their physical resistance a whole lot, but it seems to lower magical resistance more for some reason. Hanged Man is a good card, but unfortunately has a serious negative penalty for drawing it. Hanged Man appears on a fairly average basis. 15) Devil A picture of an evil demon with his hand on top of a near naked woman. She appears to be unconscious and it looks like he's hypnotizing/taking control of her. Reputation Meter -1 Summons the demon Asmodeus to perform a black attack on the enemy unit. -The Devil card has a very cool graphic effect, one of my favorites in the game. It is a very powerful attacking magical card, only faltering to those who have high black magic resistance. Devil is a decent card, but drawing it lowers your reputation. The Devil card is very common, and is easily drawn by low-alignment units that liberate towns. 16) Hierophant A picture of a shaman priest with his hands on a staff, with holy light shining from it. Characters' Alignment +2 Puts the entire enemy unit to sleep in a shower of flower blossoms. -Hierophant is a very useful card, and is one of my favorites. Of course, the unit can still have a chance to wake up if attacked, but I really like to use it to put enemy Clerics and Shamans to sleep so they don't heal their comrades (or maul your undead allies if you happen to have them in the wrong place at the wrong time!) Also really works to turn the tables back on a stupid Witch who would try to Stun Cloud you. Put her to sleep before she stuns you! :) The Hierophant card is drawn on a fairly average basis. 17) Justice Shows a knight carrying a sword and the equality-scale of justice. Characters' max HP +1 Showers the entire enemy unit in an ice storm. -The Justice card is drawn very often (and the bonus isn't that great), and its attack power is relatively average. The Justice card is an average attack card, to say the most, and the least about it. Nothing super special here. 18) Judgement Shows a female angel with her feathered wings sitting down on a stone. Characters' max HP +2 Blasts the enemy unit in an intense blast of holy light. Judgement will also instantly pulverize any undead creatures. -Judgement is the most powerful attack card, even more so than Sun and Devil. The Judgement card will REALLY hurt those with poor alignment and low white magic resistance. This blast will also fry any undead enemies that happen to be standing around, as well. The graphic effect is absolutely stunning, also. The exploding white/blue fireball is awesome. This is a great card to draw and have, but it is relatively rare to run across. Keep it if you draw it. 19) Tower A picture of an evil looking black tower in a lightning storm. Characters' Alignment -2 Hits the enemy unit in a screen-shaking earthquake. -Tower is a horrible (and evil) card, not only to draw, but to use in combat. The damage from this card is almost always awful, unless your Lord is evil and has high intelligence. Tower is drawn on an average basis, but for some reason always shows up at the wrong time! :) 20) Temperance A picture of a woman in white robes gathering water from a marsh. Reputation Meter +2 Cures your unit of any status-ailment spells when used in battle. -The Temperance card is a good card to draw (getting reputation bonuses is always a good thing!) but it doesn't have a huge practical use for combat purposes, unless you run into a Witch who will Stun Cloud you, a Cerberus who will Mesmerize you, Vampires that Charm, etc. The Temperance card has to be one of the most commonly drawn cards. This thing shows up almost on a regular basis for average to high aligned units. 21) Fortune A picture of a blindfolded woman blindly looking for a twist of fate. Reputation Meter bonus/penalty from +3 to -3, decided randomly. Causes the entire enemy unit to flee from battle. -The Fortune card isn't that great, and it only comes in handy in very rare circumstances, like if you want time to regroup or you have already lost the battle, and you want the enemy unit to retreat instead of you doing so. It does have its rare uses. Fortune is drawn on an average basis. 22) World A picture of a beautiful woman (again) in multiple colored robes representing all the points of the compass on the world map. All allied units are now effected by drawn tarot cards for the rest of the stage (ie, if you then draw a Tower, ALL of your units and characters that are deployed will lose two alignment. Draw a Chariot, and ALL characters and deployed units on your side gain two strength, etc.) Throws forth a magic shield, protecting your unit from magical attacks. -The World tarot card is another one of the really good cards to have. Not only does it have an aweseome effect for your units (draw a World and then draw Hierophants, Chariots, Hermits, and Judgements!!!) but is a GREAT card to use when coming under fire from stage bosses, and heavily magical enemy units. This also makes a GREAT card to protect your undead friends from getting fried by healing magic or a Jihad! :) This card is a MUST against Empress Endora, Sage Rashidi, Omnicron the Necromancer, Baron Apros, and Cardinal Randals. The following tarot cards DO NOT WORK on bosses! -Fortune (boss runs away; then taking the enemy HQ would be CHEEZY!) -Sun (as many bosses have low ALI in this game) -Hierophant (bosses are immune to sleep, but their bodyguards aren't) -Lovers (yeah, like Prince Gares would whack himself with his own axe) -Death (reducing him to half HP and then insta-kill would be cheap!) -Moon (does not work on him AND his unit) -Hanged Man (works on his bodyguards but not him, I believe) -Bosses are also totally immune to corresponding magic spells like Charm, Mesmerize, Stun Cloud, and Petrify, etc. (End of Tarot Card summary) Rare Items -These are extremely hard to find items in this game that can either adversely affect the abilities of characters, change their classes, or are items that help you get a really good ending. Be wary that these items are EXTREMELY hard to come across, and enemy units only drop them a small percentage of the time, if at all (again, your characters' Luck comes into play!!!) 1.Undead Staff- The Undead Staff is an extremely powerful piece of work, and it allows you to turn a Mage into a Sorcerer. You can get Undead Staffs in these ways- First, either by visiting the "Great Wizard" Borginine in the city of Anglem in Diaspola, and trading a Sentoul Demon to him by refusing his offer for $10000, and then taking the Undead Staff. Sentoul Demons show up every now and then from encounters with grateful townspeople. You will also get a Sentoul Demon from Posha (the little girl in Diaspola who has the sick and dying mother) by giving her a Golden Beehive to cure her mom. Second, is through enemy encounters. Certain enemy characters may drop one after battle, but this is all up to really slim chance. Third, is after killing Omnicron in Antalia, head back to Kander Hall, and a monk there will say "I found this in Omnicron's room", and he will give you one to use. 2.Full Moon Stone- VERY rare to get, it allows you to summon a Weretiger to recruit. This can be obtained in only two ways that I know of- First, through enemy encounters. This is rare, of course, though. Second, by getting a Tome of Myths from a monk in a city in the area of Zeteginea (or somewhere very late in the game in one of these nearby areas.) You can also buy Tomes for a lot of money in a shop in either the City of Xanadu or Zeteginea itself. The monk who is willing to trade for your Tome of Myths is somewhere in the Fort Shulamana area. 3.Undead Ring- The Undead Ring allows you to either turn a Sorcerer into a Lich, or mutate a Tiamat into a Zombie Dragon. The former is usually a better choice for this hard to come by item. First, you can get this item in enemy encounters, although this is of course very rare. Second, the Wizard Badista in Sharom is looking for a "Book of the Dead", and in fact, several copies of this book exist in this game. Revisit towns after liberating the entire stage and you may receive a Book of the Dead. Take it back to Badista for a ring. 4.Dream Crown- The Dream Crown is needed to turn an Amazon into the all-powerful Princess. You can get this in three ways- First, of course, through the SUPER RARE chance you find it after killing an imperial unit. Second, after revisiting the far NW city in Muspelm, and if your reputation is very high, you can answer a question about elegance and beauty. Choose a good answer and the monk will give you the crown. Third, you can also obtain a Dream Crown in a city in Temple Shalina (at the end of the game) if you have a very high reputation. 5.Blood Kiss- The Blood Kiss turns a Knight into a Vampire. There are two ways to get it- through either the lucky random chance you find one after a battle, or by having a low reputation and visiting a town in Temple Shalina for one. 6.Stone of Dragos- Obtained through either enemy encounters, or the Great Wizard Borginine (by refusing his offer for the Undead Staff, then choose to take the Dragos Stone.) The Stone of Dragos allows you to turn a Beastmaster into a Dragon Tamer. 7.Trade Ticket- The Trade Ticket allows you to conjure up the ever-elusive (and super expensive!) merchant who calls himself "Anywhere Jack". Jack will sell you all the status enhancing potions in the game except for the Soul Mirror (raises ALI) and the Heart of Leo (raises CHA). I suggest you have a TON of money before using the ticket to buy a lot of stuff from him! You can only get a Trade Ticket off of enemy units. 8.Mercury (needed for the Tablet of Yaru) (puzzle item)- You can get the Mercury from a wizard in Selshippe in the Pogrom Forest after completing the stage, if you have a high reputation. 9.Gem of Doun (needed for the Tablet of Yaru) (puzzle item)- You can get this gem if you have the Mercury, and by revisiting the hidden NE town in the middle of the desert in the Dalmuhd Desert stage. I believe it is named "Aliabard". The old man there will give you this glowing gemstone. 10.Olden Orb (needed for the Tablet of Yaru) (puzzle item)- Return back to Selshippe in the Pogrom Forest with the Gem of Doun, and the wizard will give you this orb. 11.Gem of Truth (needed for the Tablet of Yaru) (puzzle item)- In the Ryhan Sea, revisit it, and in one of the towns a witch will talk to you, and if you have both the Olden Orb and the Gem of Doun, she will give you this gem. 12.Tablet of Yaru (puzzle item)- Bring the Gem of Doun, Gem of Truth, and Olden Orb to Shangrila to earn the right to speak with the Goddess of Justice, Felana. She will then give you this tablet. With this tablet in your possession, you can now obtain the Zodiac Stones that are hidden in temples throughout the land (see the guide to a holy path above to find them.) 13.Brunhild Sword (equippable item) (1st of 3 Mystic Treasures) Fenril's long-lost mystic holy sword. You can get the Brunhild Sword only if you have a high reputation. It is found in the FAR northwest temple in the Kastolatian Sea. This sword now allows you to find the Chaos Gates that are in different locations on the land. These gates will allow you to travel to the floating continents and the cursed land of Antanjyl. This sword is also a super-bad-@$$ weapon, equipping it gives a +20 Strength bonus (!!!) and also counts as a white magic weapon to boot! 14.The Mystic Armband (2nd of 3 Mystic Treasures) This is the sacred wristband of Queen Floran, the former Zenobian Queen. You will get this item by having Prince Tristan confront and kill General Previa at Fort Shulamana. He will then find out that the rescue mission was in vain as Previa had already murdered Queen Floran, and Tristan then gives you the armband as a memento. 15.The Holy Grail (3rd of 3 Mystic Treasures) The Grail is the chalice King Gran used to unify the land, and this sacred goblet can be found at the Shrine of Kulyn. You must defeat General Luvalon "honorably" (no tarot cards or running away!) and if you have a high reputation, charisma, and alignment, return to Kulyn to receive the grail from the ghost of the knight Parcival. 16.Star of Heroes (puzzle item)- Really easy to get. Just liberate the hidden temple north of your starting base camp in the Sharom Border stage, and the monk will give you this emblem. This is needed to get many special characters in this game, so make sure you don't forget to obtain this! Reputation Meter Clarification- There is a meter in the intertwined dragon symbol in this game (above this meter shows the 24-hour clock and how much money you have), which rises and falls depending on what actions you do. This is your reputation. This is what the populace thinks of you, personally. The decisions you make in this game and what you have liberate cities will reflect what the people think of you. Finishing the game with an extremely high reputation meter is very important to getting a good ending. The people will not trust you if your reputation with them is shady, so, try and get it as high as possible. Your reputation meter will be affected by the following factors: 1. What unit you have liberate cities -Before you liberate a city, you should check its "vital statistics", which are labeled below in this order: NAME (name of the city) POPULATION (castle) (how many people live in this city) MORALE (cross) (how spirited/moral the people of this city are) COMPASSION (heart) (how the people feel about your rebel cause) TRIBUTE (coin) (how much money they will contribute to you each day) The MOST important two statistics are the town's Morale and Compassion levels. When liberating cities, you should in general send in a high charisma, high alignment unit to "spread the good word" of the rebellion. Towns with low morale and high compassion are most easily persuaded to your cause (and liberating it with a high ALI and CHA unit will GAIN you reputation points), and towns with high morale and low compassion are the HARDEST to persuade (and sending in a medium to low ALI and CHA unit will LOSE you reputation points.) So, alas, depending on your unit's ALI and CHA levels compared to the town's Morale and Compassion levels will affect your reputation. In general, though, use "good guy" units to liberate cities. Nobody wants to be liberated by a bunch of Demons, Liches, and Undead. :) 2. Liberating Roshian Temples -Temples give you **NO** bonus or penalty to your reputation when you liberate them, as the Roshian Monks welcome all and any in their forms, good or evil. So, if you want some tarot card bonuses for your evil units without suffering reputation, have evil units liberate the Roshian temples. :) 3. Dialogue Options -Over the course of the game, your Lord character will be involved in dialogue where you can choose your response. Depending on what you choose can affect your reputation. For instance, as an example, if you refuse to forgive Deneb the Witch after beating her, you will gain a lot of reputation points. Answering the wrong choice in dialogue options or refusing to sell/give something to someone wants it will lose you reputation points. I should also point out that if you want a good reputation, ***DO NOT*** deal with thieves or Toad the Merchant AT ANY TIME, as these are shrewd people, and dealing with them lowers your reputation. Toad always rips you off, anyway. :) Also, never torment the Old Great Wizard Borginine, as tormenting him regularly (ie, refusing to trade your Sentoul Demon to him) can kill your reputation, which is very fun to do if you are pursuing an evil path! :) 4. Lord's Level -This comes into play heavily. You should try and keep yourself OUT of combat if possible because the people like and trust a general who is weaker than his forces. This is a little easier said than done, as your Lord gets any experience exclusively from kills through Tarot Cards, and earns DOUBLE the amount of experience points that normal troops do, so the Lord character in this game levels-up EXTREMELY FAST. All I do is get into a few fights with my Lord early on to get his CHA and ALI really high, and then keep him out of action the rest of the game. So, essentially, if your Lord is a complete bad-@$$ walking tank, the people will lose trust in you, and you will lose reputation points. You were assigned to free the continent from the rule of the evil Empire, and NOT kill everything in your path. :) 5. Tarot Cards -Yes, this does affect your reputation in a way. Drawing a Temperance card will up your reputation, and drawing the Death card will lower it, etc. This is fate, in essence, as the draw of the card is random. 6. Tribute -Collecting tribute (ie, daily taxes when the tariff bells ring and the Income Projection screen pops up at high noon each day) affects your reputation. Your reputation will go down if you take longer than the expected "leeway" time period in each stage. Sitting around and collecting money each day from the people can help your war effort, but don't sit around and do it for more than 5 days (in game, not in real time, silly) or your reputation will begin to suffer. Also, towns will contribute MORE money to your cause the higher your reputation meter is. So... a big incentive to having a high reputation, as you get more cash each day! 7. Enemy re-captures town or temple/captures Rebel HQ -This will KILL your reputation a BUNCH, so don't let the Empire re- take any towns or temples you liberated from their rule, or the people will get really angry! If the enemy manages to capture your HQ (the castle your Lord's unit starts on at the start of each stage) then your forces will retreat and you'll have to restart the ENTIRE stage over again from scratch. So DON'T let the Empire re-take things you freed from them! Hard to Find (but yet purchaseable) Items- -These items are REALLY useful items to take along in your quest. They can make your journey a lot easier. -Using Rays and Moonbeams to avoid Income Projection until you are done with the stage (and set the appropriate time of day for one of your units entering combat, ie, best for midnight for evil, high noon for good), and the like is great. Take all the time you need, when it gets near midnight, just use a Ray and it goes back to high noon (without the income projection screen popping up) or vise-versa if the day is already past midnight, just use a Moonbeam. Then when you have all the enemies wiped out (except for the boss), withdraw all of your units back into your HQ, and sit back for a few game days and collect some big money from the tributes. After all, you need a lot of money to fund a very strong war effort against the Empire! -A surplus of Joker Tarots is good, so you can draw extra random tarot cards for battle when you really need some! Just use a Joker Tarot and you will draw a random tarot card, and then be asked to keep it or not. Get a truckload of Jokers and you'll never have to worry about not having any battlefield outside-enhancements ever again, and you'll get to keep using them until you draw what you want! -Getting some Dowsing Rods and Crystal Balls is good, as then you can use a "save/reload" trick to find hidden treasures and hidden cities. Use the Dowsing Rod (for example) and remember the location of the treasure on the map where it moved to, and then reload, and walk to it and get it. This is a little underhanded, but hey, HIDDEN cities/temples and BURIED treasure shouldn't be in this game, and this game is insanely involving and tough, so go for it. Therefore, you don't need to bother searching around for them if you already have a Dowsing Rod and Crystal Ball. Makes your search A LOT easier. -7-League Boots are EXCELLENT for mass-transporting units wherever you want them to go. Just liberate a city close to the enemy castle with a flying unit, and then teleport any units there that you want to see combat and level up/get stronger. -Persuasion Spell is great to take along some rare characters from the Imperial units. Why go through the SUPER HARD trouble to get a Sylph, Werewolf, Vampire, or Zombie Dragon (or other like class that usually totally sucks until it reaches its highest class level, where it becomes a nasty tank) when you could just steal one from the Empire's unit instead? To this day I have NEVER obtained a Sylph, Titan (I stole two from Norn before I fought her, then she brings two other ones along with her when she joins!), Werewolf, Vampire, or Zombie Dragon the "normal" way. I have ALWAYS stolen them from Imperial units. It is a LOT easier this way. Plus it gets rid of enemies you have to fight. :) -Cure Ankhs are awesome, as mass-healing everyone in your party 100 HP can't be beat. Speeds up your game a lot, too, rather than using 5 Cure Stones on people one at a time. These are also a necessity later in the game (after stage 16 or so) when most enemy units have Magi and Muses and stuff, things with attacks that hit your ENTIRE unit at once. These are some handy (but not ALL, you can find some of these at several spots) of these items' locations: -Should you wish to look at all of the hidden towns, temples, and treasures, I would like to refer you to Mr. Anzulovich's FAQ on GameFaqs, as this lists every buried treasure and hidden town in a specific section, but once you get some Crystal Balls and Dowsing Rods, this isn't necessary. Just use the items to find what you want, and then save/reload and walk over them yourself. You can also find more detailed "numerical" information on stage bosses and units alike. Opinions of best units/best characters to use- -Here's my list of what I think is totally a "hammer" combo of units in this game. Front Row All-Stars (in no real best order)- 1. General- These guys are insanely strong and tough. Tristan and Debonair are truly front-line hammers. 2. Dragoon- Fenril, Slust, and Fogel are dynamic opponents for the enemy. They are fearsomely strong with three attacks in the front. 3. Paladin- These guys are fantastic, with three attacks. 4. Samurai Master- Again, just like the Paladin, only faster in agility (little less HP) and three attacks. 5. Ninja Master- Phenominal agility and good intelligence, they make a good "bad guy" front liner. 6. Zombie Dragon- A GIGANTIC sponge who can absorb insane amounts of damage, while protecting the rest of your unit. Their combat abilities are only average to good, but they are awesome for protective purposes. Back Row All-Stars (in no real best order)- 1. Princess- A rare treat to get, but the Princess is in my opinion the best character class in the game. The most powerful white magic attack in the game, plus the +1 Attack bonus to your entire unit (including herself!) if she is the unit leader. Can't best that! 2. Lich- Another rare treat, but more common than the Princess, three all-hit magic spells in the back usually sends enemies to an early grave quickly and efficiently. 3. Titan- Their "Wind Shot" spell is VERY strong for a "monster" class character. This causes good damage to any small targets, and utterly decimates magician-type characters if it connects. 4. Sorcerer- Well, sometimes you can't get a Lich. Really good, but just two all-hit spells instead of three, and he only recruits second- rate undead creatures. 5. Devil- Evil at its finest, this little dude possesses the most powerful black magic attack in the game. He only drops his meteors once per combat, but they HURT. 6. Seraphim- If you can't get a Princess, for a white magic super attack, she's probably your next best thing. 7. Sylph- Same goes with the Seraphim. Can't get a Princess? She's good. The Magic Missile attack does wonders of damage. Sylphs are really intelligent and are ungodly agile, so they're really hard to hit to boot. 8. Flare Brass/Platinum Dragon/Tiamat- The super-powers of each class of dragon, with powerful all-hit back row magic attacks. It takes a LOT of work to get a Flare Brass or Platinum Dragon (the evil Tiamats are EASY to get but aren't as good of fighters!) but it pays off! Super-Good Unit Combos- (these are some of my personal favorite units) 1. Front Row- Two or three Paladins/Samurai Masters Back Row- Two or three (depending on the front) Muses or Enchanters -This unit is a HAMMER of a good-guy unit. These guys (and gals) can liberate cities at will with usual good bonuses to your reputation, and they have so many attacks (a good bit of which strike the whole unit) that most enemies die very quickly. 2. Front Row- Two Paladins Back Row- Two Nixies and a Princess (usually Aisha turned into one) -This unit has a lot of powerful attacking potential. Nixies who can cast TWO Ice Storms instead of one become double the trouble. The Paladins strike FOUR times as well, but are in the front mostly as an insurance policy for safety. 3. Front Row- Nothing Back Row- Two Titans and a Princess (usually Norn turned into one) -Titans who can strike THREE Wind Shots per combat become so nasty you should see what this does to enemy units. Norn usually dishes out about 90 damage to each opponent since her INT is around 160 or so! 'Nuff said about these guys. 4. Front Row- One Iron Golem Back Row- Three Cherubims/Seraphims -This is what I like to do with Yushis and her unit. The Iron Golem in the front is a bit of an enigma, but Iron Golems are actually pretty good. Especially if you drop a couple speed and vitality potions on him. The white magic from the back provides excellent support. 5. Front Row- Two Wraiths Back Row- Two Phantoms and either a Devil or a Lich -This is a phenominal "bad guy" dark unit. UNTOUCHABLE to any form of attack except white magic, these guys make good for beating up units you don't want your good guys to fight. Undead can care less about Alignment and Charisma. And if you're looking for Figaro's Durandal Sword, most of the units in the Kalbian Peninsula stage will be WELL BEHIND your own units by this time, so send out all of your evil guys and mop the floor with the enemy! And check out the damage this unit can do when the sun goes down! 5. Front Row- Three Ninja Masters Back Row- One Tiamat -This is another great "bad guy" unit. You can also swap the a Ninja Master or two into the back row if you need some good all-hit ninjutsu for the coming fight. 6. Front Row- One Zombie Dragon Back Row- One Muse and two Sylphs -A weird combo, but really effective. Your unit will also move quite quickly over water as well, due to the presence of the Zombie Dragon! And if the Sylphs and Muse can't finish off an enemy, the Zombie Dragon puking all over it probably will. :) 7. Front Row- One Dragoon (Fenril, Slust, or Fogel) Back Row- Two "ultimate dragons" of their matching element (ie, Platinum for Fenril, Brass for Slust, and Tiamat for Fogel) -A very powerful stomper unit. Don't worry about your Dragoon being all by him/herself in the front, they will be able to hold their own. The Dragoon will also really boost the stats of the dragons of their matching element as well. 8. Front Row- Three Werewolves Back Row- One Vampire and one Werewolf -A sundown ONLY unit. These guys will be absolutely worthless during the day (sarchasm alert- four Lycanthropes and a Coffin=AWESOME!!!!), so remember- combat at night-time only! The Werewolves will have so many attacks it'll make the enemy's head spin. Plus use your battle tactics carefully and zap stuff like enemy Sorcerers and Enchanters and the like with the Vampire's "Charm" spell, and laugh at the hilarity insuing as the Enchanter or whatnot starts casting Acid Clouds on his own allies! :) -Those are some of my favorite suggestions, but make what units you want. After all, true knowledge is best gained through your own experience and experimentation. Cheats and Easter Eggs -There really aren't any ways to cheat in this game, but there are two "codes" that you can use to get some more enjoyment out of this game. Both cheats are accomplished by entering these as your name in the New Game area where Warren reads your fortune with the tarot. 1) Enter name as "MUSIC/ON" -This lets you listen to all of the music tracks in the game (except for the ending credits music, you must win the game for that.) Nothing really special, except if you just wish to listen to some of the game's good music tracks like "Santa's Coming", "Go-Go March" and "Thunder". 2) Enter name as "FIRESEAL" -This lets you play the ultra-hidden secret stage of "Dragon's Heaven", which is not accessable in the normal story mode. This is a one-time play level, where you start with very strong characters (around Level 15 or so) and $300,000. This is a roughly tough stage, as the enemy is strong as well. Enjoy, as once you beat this stage you get a fairly cheesy ending description and then the game's credits. What units you get to play with in this scenario depend on your answers to the tarot card questions. Endings -There are supposedly 12 or 13 different endings in Ogre Battle, only four or five of which I have actually seen. You will know which ending you will get depending on what Tarot Card you receive for your rating at the end. The endings I have gotten are: -Tower (the very first time I played through the game, on the SNES version, when I was 14. Boy, did I suck at it then. Had 78 chaos pts.) -Emperor (Lord character ascends the throne, 100 chaos pts.) -World (theoretically the "very best" ending in this game, 100 pts.) -Empress (female Lord takes the throne, 100 pts.) -Priestess (female Lord marries Prince Tristan, became Queen, 100 pts.) Information About the Author -Well, some of you will probably skip right over this, but, well, here's a little information about me: -I'm a native Wisconsinite, and I attend college at the University of Wisconsin at Madison (aka, "The Badgers") -I am a rower on the UW-Men's Rowing ("Crew") Team, and have rowed on the team for three years, and have one medal at national championships. -I am studying French and language for my major, and wish to teach French someday. -I played soccer for a good number of years back in the day when I was a kid. I have 14 years of experience, but I wasn't that good. -On September 9th, 2004, I will be 22 years old. -I've had my fare share of rowing medals, but a fellow teammate of mine won gold in the Olympic USA Men's 8+ in rowing at Athens this year, 2004. Congrats, Beau, you're the finest athlete I've ever known. You were one of my biggest sources for inspiration in our sport. :) Interests: -Video Games (hah, that was a no-brainer!) such as: Ogre Battle, games in the Resident Evil series (Gamecube version only), games in the Metal Gear series, Super Smash Brothers, Driver (smashing into police cars is kinda funny, acting like a Blues Brother), Final Fantasy series (though I've moved away from playing those, as I took my older bro's advice that RPGs are DEADLY to your grades in college), any of the Mega-Man games (the X series 1-3 are my favorites) and some limited computer games- Heroes of Might and Magic 3 (I'm EXTREMELY good at that game; there is a BAD reputation of a player named "Emperor Egley" --ie, me-- somewhere on the internet, as this character frequently kills EVERYONE he plays, and Conflux OWNZ, yo'!), and Starcraft-- I only play BroodWar, as the old edition is heavily unbalanced (ie, Protoss are too bad-@$$ and Terran flat out suck!) I am very good at Starcraft, but not phenominal, I don't play it all hours of the day! :) And I have played Medal of Honor: Allied Assault and Battlefield: Desert Combat from time to time on network play. Some crazy and stupid tough video game accomplishments of mine: 1) Beating Resident Evil as Chris on Hard mode. Beating it as Jill on "Real Survival" WITHOUT cheating using the "Grenade Launcher Glitch". However, I'm not stupid or insane enough to try "Invisible Enemy". 2) Beating MGS: Twin Snakes on Extreme. 3) Beating MGS2: Substance on Extreme, and completing 93% of the VR missions (the last five missions as MGS1 Snake are practically IMPOSSIBLE without cheating) and nabbing all the Dog Tags. 4) Beating Ogre Battle and getting the best ending. 5) Beating the Heroes of Might and Magic 3 campaigns without cheating. 6) Beating the Starcraft campaigns (both versions) without cheating. 7) Beating Doom 64 on the "WATCH ME DIE!!!" difficulty setting (I tell you, fighting four Cyberdemons on the second to last level, three of them at once, is NOT my definition of fun.) 8) Beating Star Wars 64: Shadows of the Empire on Jedi setting, collecting all the challenge points. 9) Beating Fallout 2 by liquoring up the final boss, Frank Horrigan. Used the Mutated Toe on him, too. Then shot him repeatedly in the eyeballs with the Gauss Rifle, and used the Vindicator Minigun. :) 10) Beating Ninja Gaiden 3 on the NES, which was terribly hard because there's a glitch in the USA version where you take massive damage when hit!!! 11) Beating the original MGS1 on the PSX on "Extreme". 12) Fully beating all the missions on MGS: VR Missions on the PSX. 13) Earning all the cheats on Perfect Dark without using a Gameshark or whatnot to get them. Plus I just plain owned the Combat Simulator against ANYONE I've ever played. Bond included, too, with great abilities for Deathmatch and also got all the cheats. 14) Beating Hexen 64 as all three characters on the hardest difficulty. 15) Beating Final Fantasy V, by far the hardest FF ever made. There are more, but they slip my mind at the time. Favorite Video Games: Resident Evil (Gamecube re-make) Metal Gear 2: Solid Snake (the one on the MSX) Super Conflict (a fun old SNES strategy game pitting the former USSR and the USA in a fantasy war setting in the middle-east. Fun to play against a friend) Heroes of Might and Magic 3 Starcraft: Brood War Metal Gear Solid 2: Substance Metal Gear Solid: Twin Snakes International Superstar Soccer 64 Super Smash Brothers 64 Ogre Battle Megaman X-3 Perfect Dark Fallout 1 and 2 Driver: You are the Wheelman (PSX) Hated Video Games (games I despise): Race Drivin' (play this gem on the SNES, I dare you.) Final Fantasy V (I HATED Exdeath and everything about him. Game-play is GREAT; storyline SUCKS!) Super Noah's Ark 3D (ran across this SNES game on the internet, god, does it suck! What a crazy rip-off of Wolfenstein 3D!) Final Fantasy 8 (BLAUGHHH!!!!) Any games that are totally japanimation, such as Xenogears, Phantasy Star Online, and whatnot. Neverwinter Nights (HIGHLY addictive, and you meet some REAL nerds there. Plus everyone practically tries the same path- Red Dragon Disciple, which has been banned on many servers) Starcraft (original version on-line) -HIGHLY unbalanced, everyone online always plays as Protoss. Little teenagers backstab everywhere. Hense why "CaptainJeffrey" (me on Battle.net) refuses to play ANY "Melee" type games or ANY maps without the "Blizzard Seal of Approval" (meaning it's an untampered map file.) It's "Free-for-All" for me, and an official Blizzard map, or I don't play. I've had enough of me playing and killing all the enemies only to get backstabbed by my immature kiddie allies. Heroes of Might and Magic 1- the computer CHEATS SO ROYALLY in this game it isn't even FUNNY. Heroes of Might and Magic 3 on-line, before version patch- Castle was SERIOUSLY unbalanced (Angels and Archangels costing only MONEY), glad to see it fixed. Fortress was also horribly WEAK, and they've since suped-up the reptiles' power. I've never lost a game of Heroes 3 where you had to eliminate opponents to win, but I was just annoyed at how many people played as Castle all the time. Also seen many of the kiddies have stopped playing as Castle since that patch fix happened, too. :) There's my stuff about video games. -Rowing, I got into it after getting into college and just walking on the team and making it. Finally found a sport I was good at. There's more info about me in the athletic field on the Wisconsin University webpage at. Just go to athletics, "Men's Rowing", and then click on my name in the bios. You also get to see a picture of my FABULOUS mug. Creepy, aren't I? :) -Soccer, swimming, and just working out in general to stay fit and healthy. -Sleeping late whenever I get the opportunity. -I also play (or at least used to) a table-top board/strategy wargame called "Warhammer 40000", made by GW (Games-Workshop.) I have recently stopped playing, but I still have all of my fully-painted figures packed away somewhere (I used to love to do artwork, so my paint-jobs aren't bad, but not 'Eavy Metal or high experience quality.) I have roughly 9000 points of Blood Angels (started them back in 1997), 2500 points of Eldar (Biel-Tan craftworld), 2000 points of Tyranids (Tiamat Brood), and 1000 points of Imperial Guard (UED Earth Defense Force.) I have stopped playing because this hobby has become FAR too expensive, not to mention in my opinion the niceness of social gaming is going down the toilet these days. People I run into to play take this game too damn seriously. -I am a super fanatic of playing "Space Hulk", another GW board game, which is basically GW's total and direct rip-off of the movie "Aliens" (which is also one of my favorite movies.) My friends and I always love playing Space Hulk, a classic "Man vs. Alien" board game. Making your own maps and missions (the ones in the book are by far way too easy and non-involving for the Marines) with the floor-tiles and whatnot in the box. I actually own two copies of the game, for more floor tiles and goodies. -Well, that's all about me. Disclaimer -This Ogre Battle FAQ is completely UNofficial and is not endorsed/affiliated with Enix, Quest, Atlus, or any of the developing team/manufactureurs. -Please do not distribute portions of this FAQ and take credit for any work you have not done. Plagurism sucks, man, so NEVER do it. Should you wish to use this FAQ on your website, please just e-mail me. I am near certain that I would not refuse your offer. -You may copy this FAQ in its ENTIRITY without ANY alteration for your own personal use. -This FAQ was authored by Jeff Egley (myself), with no co-authors. All description and work therein was fully typed and written by me. All of the opinions/errata are my experiences with playing through this game several times. -There were several borrowed exerpts I used from Daniel's FAQ (also located on GameFaqs) consisting of: 1) Several statistics on several characters in this game. 2) A couple parts on a checklist to pursuing a very good ending. 3) A couple of ways to get special characters (namely a way to get Galf and Deneb, some of the "bad" characters in this game.) 4) A couple bodyguard information on stage bosses- namely I had already played through the stage and didn't want to check back that far :) Contact Information- You can contact me at my student e-mail address listed at the top of this FAQ. Feel free to drop me a line, but please remember these golden-rule conditions: 1) Do not e-mail me with flame/hate/spam e-mail. Constructive criticism is OKAY to a mild part, but anything else I don't like at all. This will promptly get you put on my block list. 2) Don't e-mail me if the answer you are looking for can be found in this FAQ. Read through this first, and THEN if you are stumped, drop me a line. If your question is good and valid, I will respond. 3) Don't ask me stupid questions. 4) Don't ask me anything about my personal life or how rowing is going with me or whatnot. It's not your business, and not important to a person such as yourself whom I do not know and will most likely never ever see. 5) Do not submit my e-mail address to porn sites or whatnot. I get enough viagra advertisements as it is, and if I find out you did it, a very mean Jeff will come and visit you and knock your lights out. :) 6) I am a senior in college, so there are many priorities I have. I will probably get around to your question, though. Have patience. 7) DO NOT DISTRIBUTE THIS FAQ OR PARTS OF IT AS YOUR OWN MATERIAL. PLAGURISM IS A MOTHER OF ALL SINS, ESPECIALLY IN COLLEGE! NEVER TAKE CREDIT FOR ESSAY/WRITTEN/RESEARCH WORK YOU NEVER DID! 8) "Don't be stupid." It's a rule we have in rowing, and anything not listed above falls under this rule. Use your best judgement. :) -That should be all. WHEW, what a lot of typing! Enjoy the read, and better yet, a very involving and excellent gem of a game! -Jeff. | http://www.gamefaqs.com/snes/588541-ogre-battle-the-march-of-the-black-queen/faqs/32158 | CC-MAIN-2015-40 | refinedweb | 37,177 | 67.79 |
Create a Primefaces JSF project with Maven and Wildfly
October 30, 2019
I'm currently on my way to Fuerteventura to enjoy a week of holidays ☀️ Earlier this year, I found out that writing blog posts was a great way to use wisely my time spent traveling, that's why I'm repeating the experience.
When I thought about which subject I should write about earlier this morning (I don't generally have any plan in advance when it comes to writing) I came to the idea that it would be maybe interesting to share my favorite JSF trick (or hack, depends if you see the glass half empty or full). But before doing so, I had to initialize a clean blank project, that's why I've decided to first write this tutorial 😋
But why a JSF project?
But why a JSF project?
Honestly, I don't know exactly why anyone would be still interested to create a brand new JavaServer Faces API (JSF) project in 2019 or why would anyone even read this article 🤣. Not that I don't like Java, I still do and I still think it's a good match for certain types of projects, notably when it goes to the back- and middle-end layers but I would personally not use or advice it for the frontend part of any new projects.
That's why I'm really curious to hear your voice, why are you reading this article? Why are you looking to create a JSF project? Let me know with a comment 😁
Getting started
In this article we are going to follow the following steps:
- Create a new web project
- Add a Wildfly development server to our tooling
- Load and configure JSF
- Implement Primefaces
Let's get started 🚀
1. Create a new project
To create a new project, we are going to use Apache Maven and its web starter kit or as it is described in its documentation "an archetype which generates a sample Maven webapp project".
For this purpose we run the following command in a terminal:
mvn archetype:generate -DgroupId=com.jsfdemo.app -DartifactId=jsf-demo -DarchetypeArtifactId=maven-archetype-webapp -DarchetypeVersion=1.4 -DinteractiveMode=false
If everything went according plan, we should be able to change directory and compile the project without any errors:
cd jsf-demo/ && mvn package
2. Add a Wildfly development server to our tooling
WildFly, formerly known as JBoss, is an application server authored by JBoss, now developed by Red Hat. Wildfly could be added to Maven's project thanks to the plugin
wildfly-maven-plugin. Through its usage you could either interact with your local installed server or deploy one on the fly which is the option we are going to use.
To add it to our project, we are going now to edit our
pom.xml. We add a new
<dependency/> to our
<dependencies/> and we add it as another
<plugin/> too.
<dependency> <groupId>org.wildfly.plugins</groupId> <artifactId>wildfly-maven-plugin</artifactId> <version>2.0.1.Final</version> <type>maven-plugin</type> </dependency> <plugin> <groupId>org.wildfly.plugins</groupId> <artifactId>wildfly-maven-plugin</artifactId> <version>2.0.1.Final</version> </plugin>
Once the configuration saved, we could build and install our project and run the application to test our setup with our browser respectively should gives us access to its administration console and to a default "Hello World" page.
mvn clean install && mvn wildfly:run
Administration console
"Hello World" page
Note
This Wildfly plugin doesn't work, out of the box, offline. Even if I fetched everything and already ran my project before taking the plane, I was unable to run it during the flight.
3. Load and configure JSF
There are different implementations of the JavaServer Faces API (JSF). For the purpose of this tutorial we are going to use the one from Oracle which we are going to add as a new
<dependency/> to our
pom.xml.
<dependency> <groupId>com.sun.faces</groupId> <artifactId>jsf-api</artifactId> <version>2.2.20</version> </dependency>
Beside the dependency, we also have to configure our application server to make it able to resolve
jsf and
xhtml target pages and to make these able to communicate with our beans. This configuration find place and in
src/main/webapp/WEB-INF/web.xml:
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "" > <web-app> <display-name>Archetype Created Web Application</display-name> <context-param> <param-name>javax.faces.PROJECT_STAGE</param-name> <param-value>Development</param-value> </context-param> > <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.xhtml</url-pattern> </servlet-mapping> </web-app>
Our application being configured, we could created our first Java bean,
HelloWorldBean.java, in
src/main/java. This class will be a simple backed bean which exposes a method to say hello to the world from Fuerteventura.
import java.io.Serializable; import javax.inject.Named; import javax.faces.view.ViewScoped; @Named("helloworld") @ViewScoped public class HelloWorldBean implements Serializable { public String getMessage() { return "Hello World from Fuertefentura"; } }
Finally, to present this message, we add a new servlet,
hello.xhtml, in
src/main/webapp which uses our above bean.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" ""> <html xmlns=""> <head> <title>#{helloworld.message}</title> </head> <body> #{helloworld.message} </body> </html>
As before, to try out our code, we build our project and run the server again.
mvn clean install && mvn wildfly:run
If we access with our browser, we should now see the friendly message as title and content of the page.
"Hello World form Fuerteventura"
4. Implement Primefaces
Primefaces is an UI toolkit build at the top of JSF. It add multiple components like table, panel, dialog, etc. You might not need it but I do need it for my next blog post, therefore, let's add it to our project too 😇
We proceed as the pasts steps by adding a new
<dependency/> to our
pom.xml:
<dependency> <groupId>org.primefaces</groupId> <artifactId>primefaces</artifactId> <version>7.0</version> </dependency>
No special configuration is needed and out of the box we should already be able to use their components. We could for example extend our
hello.xhtml with an horizontal panel.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" ""> <html xmlns="" xmlns: <h:head> <title>#{helloworld.message}</title> </h:head> <h:body> <p:panel <h:panelGrid <img src=""/> <h:outputText </h:panelGrid> </p:panel> </h:body> </html>
We could again build and start our application server to try out our implementation.
mvn clean install && mvn wildfly:run
Finally we could check in our browser to check if everything is correctly running.
“Hello World from Fuerteventura” presented in a Primefaces’ panel
Voilà, we did it! We created a Primefaces JSF project with Maven and Widfly and are now able to make some testing 🎉 Moreover, even if I'm not looking forward to going home, I will be able to use this blank new project as a starter kit for my next article 😆
To infinity and beyond 🚀
David | https://daviddalbusco.com/blog/create-a-primefaces-jsf-project-with-maven-and-wildfly/ | CC-MAIN-2019-47 | refinedweb | 1,172 | 54.32 |
When a user browses to a relying party (RP) application in which the IP-STS or RP-STS is
AD FS 2.0, the user provides credentials to the STS and subsequently fails before the STS response is posted either to the RP or the RP-STS (depending on your deployment scenario).
Event Viewer shows Error Event 111 in the AD FS 2.0/Admin log with the following detail:
The Federation Service encountered an error while processing the WS-Trust request.
Request type:
Additional Data
Exception details:
System.ArgumentException: ID4216: The ClaimType '<some-value>' must be of format 'namespace'/)
If you test this scenario using IDP-initiated sign-on, you may find that access to the RP works with no error.
The URL to test IDP-initiated sign-on to
AD FS 2.0 is: https://<sts-DNS-name>/adfs/ls/idpinitiatedsignon.aspx
In short, the STS has a Claim Description with a Claim Type (URI) which does not meet the format requirements for the SAML token requested.
SAML tokens have URI (ClaimType) rules that will differ based on the version of the SAML
token you intend to issue.
AD FS 2.0 supports WS-Federation, WS-Trust, and SAML 2.0 protocols. WS-Federation
protocol only supports SAML 1.1 tokens. WS-Trust
protocol can work with multiple token types. SAML 2.0
protocol only supports SAML 2.0 tokens.
SAML 1.1 tokens have strict URI rules which state that the format must be 'namespace'/'name'. These can be constructed many ways, and here are a few common examples:
SAML 2.0 tokens do not have the same URI requirements, and simple names can be used. Examples:
When you are browsing to the RP application first, you are performing RP-initiated sign-on which could result in a request on any of the supported protocols. If your RP is protected by WIF, then your request will be WS-Federation which means a SAML 1.1 token.
A Fiddler trace will clue you in to which protocol you are using. If you are doing IDP-initiated sign-on, then you are utilizing SAML 2.0 protocol, which means you get a SAML 2.0 token. This explains why the IDP-initiated sign-on scenario may be working for
you.
The easiest solution is to change your Claim Descriptions to only include Claim Types which are compliant with SAML 1.1 token rules. That way, it doesn't matter which protocol or token type you are using, and the Claim Description will be versatile for any
protocol scenario (consider protocol transition).
If there is some reason the claim type cannot be changed, then you need to ensure that your RP-initiated request utilizes a request for a SAML 2.0 token, or you could move toward a IDP-initiated solution which would guarantee the use of a SAML 2.0 token. | http://social.technet.microsoft.com/wiki/contents/articles/1431.ad-fs-2-0-the-admin-event-log-shows-error-111-with-system-argumentexception-id4216.aspx | CC-MAIN-2016-07 | refinedweb | 482 | 64.81 |
--- Comment #6 from Ionut Oancea <ionutf.oancea@yahoo.com> ---
I stumbled into this recently and I was very surprised that such an old report
wasn't concluded yet. In our MT application, we use APR pools extensively and
an issue there would definitely be a big problem.
Therefore, I have decided to do an analysis of the affected code (aka
allocator_alloc and allocator_free functions) to hopefully help in closing this
bug or just help others stuck with this.
Note: Unfortunately, I have only analyzed the code for the latest APR release
(version 1.7.0) so I won't address the version being reported (hopefully, no
one uses that old version by now)
The thread analyzer tools (helgrind, drd, tsan) trigger warnings about
unprotected read access in 2 places:
===================== 1 ===========================
if (index <= allocator->max_index) { // `allocator->max_index` is read w/o
mutex protection
#if APR_HAS_THREADS
if (allocator->mutex)
apr_thread_mutex_lock(allocator->mutex);
#endif /* APR_HAS_THREADS */
===================================================
===================== 2 ===========================
else if (allocator->free[0]) { // `allocator->free[0]` is read w/o mutex
protection
#if APR_HAS_THREADS
if (allocator->mutex)
apr_thread_mutex_lock(allocator->mutex);
#endif /* APR_HAS_THREADS */
===================================================
To check whether the reports are harmless or not we'll have to see what happens
when the unprotected condition isn't `true` after the mutex is acquired.
For case 1, this means `index > allocator->max_index`. The line that deserves
attention is the one which uses `index` - aka `ref = &allocator->free[index]`.
In our scenario, `ref` will point beyond the current `max_index` which looks
dangerous at a 1st sight. After a closer inspection, the access is ok because:
* the `free[]` field is a MAX_INDEX (where `allocator->max_index <
MAX_INDEX`) array - so it can't be an out-of-bounds read.
* the emptied entries from `allocator->free` will always point to NULL making
`*ref == NULL` - so the reference won't point to dangling or in-use node.
For case 2, the race condition will be `allocator->free[0] == NULL` that will
affect the `ref = &allocator->free[0]` line. This branch is a bit more simple
and one can easily see that the result from `*ref` is properly checked against
NULL - aka `while ((node = *ref) != NULL ...` and later `if (node) {`.
In conclusion, for above read races, the existing code won't create any issue
and, in both cases, the new `node` will end up being allocated.
--
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You are the assignee for the bug.
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For additional commands, e-mail: bugs-help@apr.apache.org | http://mail-archives.us.apache.org/mod_mbox/apr-bugs/202010.mbox/%3Cbug-48535-43213-5fk5gEkvWw@https.bz.apache.org/bugzilla/%3E | CC-MAIN-2021-04 | refinedweb | 412 | 50.97 |
On Thursday 30 March 2006 22:31, M.-A. Lemburg wrote: > I don't really care about the name, but please be aware that > you are talking about adding a *very* popular module name to > the top-level Python namespace if you go for "db" or "database". > > Why can't we just have the pysqlite package as top-level > package, with a slight change in name to prevent clashes > with the external distribution, e.g. sqlite ?! > > Such a module name is less likely to cause problems. Excellent point. Hm. Maybe we should just go with 'sqlite', instead. Anyway, at the moment, there's 'db.sqlite' all checked in and working on a branch, at svn+ssh://pythondev@svn.python.org/python/branches/sqlite-integration or, if you use a readonly version (you can use 'svn switch URL' to change a current trunk checkout to the branch without having to checkout a whole new version). It is from sqlite 2.1.3. Gerhard is cutting a 2.2.0 which reduces the requirement for the version of sqlite3 that is required. Currently, it needs 3.2.2 or later. There's tests (which pass), setup.py magic to find a correct sqlite3 version, and the like. Still to do: Windows buildproj Documentation Upgrade to the updated pysqlite once it's out maybe switch from db.sqlite to just sqlite (trivial enough change). Anthony -- Anthony Baxter <anthony at interlink.com.au> It's never too late to have a happy childhood. | https://mail.python.org/pipermail/python-dev/2006-March/063156.html | CC-MAIN-2014-15 | refinedweb | 249 | 76.72 |
Fenics and gmsh
I downloaded docker and set it up using their script.
fenicsproject notebook testbook
creates a notebook
Then
fenicsproject start testbook.
Starts a jupyter server.
You need to use python 2. Fenics is not installed for python 3 as far as I can tell.
I took the first example out of the tutorial book
You need
%matplotlib inline
in order to see the plots.
I installed solidpython which is a pythony version of openscad.
So you can output a scad file, but then you need to run openscad to convert it further.
brew install Caskroom/cask/openscad
puts it into an app folder and not in the path of the terminal
import os os.system('/Applications/OpenSCAD.app/Contents/MacOS/OpenSCAD -o test.stl test.scad')
pip install numpy-stl
ooh
%matplotlib notebook
makes an interactive plot. nice.
gmsh is necessary. Perhaps a better tool chain would just use gmsh and ignore the scad stuff.
you can take a mesh from gmsh
gmsh
first click add points. add them in in by pressing e.
thenadd line
the add plane surface.
add physical group to start labelling boundaries.
click 2d under mesh.
refine it a couple times maybe then save the .msh
dolfin-convert untitled.msh test.xml
This is an answer as to how to grab these xml files
So here’s a start
This is not the cleanest workflow. | https://www.philipzucker.com/fenics-and-gmsh/ | CC-MAIN-2021-39 | refinedweb | 232 | 77.94 |
18 August 2008 21:59 [Source: ICIS news]
NEW DELHI (ICIS news)--India’s new urea investment policy for expansion and greenfield projects would yield a return of 15-18% on equity for manufacturers, Standard and Poor’s Indian subsidiary CRISIL said on Monday.
“We believe the new investment policy will augur well for the sector,” the ratings major said. It said it believed the availability of natural gas as feedstock to urea industry would not be a constraint after December.
CRISIL also said it assumed long-term natural gas price of $8-9/million British thermal units (mbtu).
CRISIL analysed the policy that was approved by Cabinet Committee on Economic Affairs (CCEA) on 8 August.
“A boost in capacity additions will reduce ?xml:namespace>
The policy allows companies to sell additional urea resulting from a revamp of existing units at 85% of the import parity price (IPP) with a floor price of $250/tonne and ceiling price of $425/tonne.
The sale of urea from expansion projects from would be allowed at 90% of IPP. The urea from revived mothballed public sector units would be recognised at 95% of IPP. The respective floor and ceiling prices would be same as in the case of revamps.
“We have observed a strong correlation between crude oil and urea prices,” said CRISIL Research head Sudhir Nair. “Crude oil prices are expected to decline sharply to around $84/bbl by 2012. Urea prices too are expected to decline to around $400/tonne - a level closer to the ceiling price fixed by the new fertilizer policy.”
Urea currently trades at $700/tonne in the international markets, against 10-year average price of $190/tonne and five-year average of $273/tonne.
The price of urea from
The government would also encourage the establishment of overseas urea joint ventures (JVs) by offering firm urea off-take contracts to JVs.
To discuss issues facing the chemical industry go to ICIS connect | http://www.icis.com/Articles/2008/08/18/9149840/sps-crisil-sees-india-urea-increase.html | CC-MAIN-2014-10 | refinedweb | 325 | 60.55 |
0,3
The earliest publication that discusses this sequence appears to be the Sepher Yezirah [Book of Creation], circa AD 300. (See Knuth, also the Zeilberger link) - N. J. A. Sloane, Apr 07 2014
For n >= 1, a(n) is the number of n X n (0,1) matrices with each row and column containing exactly one entry equal to 1.
This sequence is the BinomialMean transform of A000354. (See A075271 for definition.) - John W. Layman, Sep 12 2002. This is easily verified from the Paul Barry formula for A000354, by interchanging summations and using the formula: Sum_k (-1)^k C(n-i, k) = KroneckerDelta(i,n). - David Callan, Aug 31 2003
Number of distinct subsets of T(n-1) elements with 1 element A, 2 elements B,..., n - 1 elements X (e.g., at n = 5, we consider the distinct subsets of ABBCCCDDDD and there are 5! = 120). - Jon Perry, Jun 12 2003
n! is the smallest number with that prime signature. E.g., 720 = 2^4 * 3^2 * 5. - Amarnath Murthy, Jul 01 2003
a(n) is the permanent of the n X n matrix M with M(i, j) = 1. - Philippe Deléham, Dec 15 2003. - Rick L. Shepherd, Jan 14 2004
From Michael Somos, Mar 04 2004; edited by M. F. Hasler, Jan 02 2015: (Start)
Stirling transform of [2, 2, 6, 24, 120, ...] is A052856 = [2, 2, 4, 14, 76, ...].
Stirling transform of [1, 2, 6, 24, 120, ...] is A000670 = [1, 3, 13, 75, ...].
Stirling transform of [0, 2, 6, 24, 120, ...] is A052875 = [0, 2, 12, 74, ...].
Stirling transform of [1, 1, 2, 6, 24, 120, ...] is A000629 = [1, 2, 6, 26, ...].
Stirling transform of [0, 1, 2, 6, 24, 120, ...] is A002050 = [0, 1, 5, 25, 140, ...].
Stirling transform of (A165326*A089064)(1...) = [1, 0, 1, -1, 8, -26, 194, ...] is [1, 1, 2, 6, 24, 120, ...] (this sequence). (End)
First Eulerian transform of 1, 1, 1, 1, 1, 1... The first Eulerian transform transforms a sequence s to a sequence t by the formula t(n) = Sum_{k=0..n} e(n, k)s(k), where e(n, k) is a first-order Eulerian number [A008292]. - Ross La Haye, Feb 13 2005
Conjecturally, 1, 6, and 120 are the only numbers which are both triangular and factorial. - Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Mar 30 2005
n! is the n-th finite difference of consecutive n-th powers. E.g., for n = 3, [0, 1, 8, 27, 64, ...] -> [1, 7, 19, 37, ...] -> [6, 12, 18, ...] -> [6, 6, ...]. - Bryan Jacobs (bryanjj(AT)gmail.com), Mar 31 2005
a(n+1) = (n+1)! = 1, 2, 6, ... has e.g.f. 1/(1-x)^2. - Paul Barry, Apr 22 2005
Write numbers 1 to n on a circle. Then a(n) = sum of the products of all n - 2 adjacent numbers. E.g., a(5) = 1*2*3 + 2*3*4 + 3*4*5 + 4*5*1 +5*1*2 = 120. - Amarnath Murthy, Jul 10 2005
The number of chains of maximal length in the power set of {1, 2, ..., n} ordered by the subset relation. - Rick L. Shepherd, Feb 05 2006
The number of circular permutations of n letters for n >= 0 is 1, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, ... - Xavier Noria (fxn(AT)hashref.com), Jun 04 2006
a(n) is the number of deco polyominoes of height n (n >= 1; see definitions in the Barcucci et al. references). - Emeric Deutsch, Aug 07 2006
a(n) is the number of partition tableaux of size n. See Steingrimsson/Williams link for the definition. - David Callan, Oct 06 2006
Consider the n! permutations of the integer sequence [n] = 1, 2, ..., n. The i-th permutation consists of ncycle(i) permutation cycles. Then, if the Sum_{i=1..n!} 2^ncycle(i) runs from 1 to n!, we have Sum_{i=1..n!} 2^ncycle(i) = (n)!. - Thomas Wieder, Oct 11 2006. - David Callan, Mar 30 2007. This observation is a more formal version of the comment given already by Rick L. Shepherd, Jan 14 2004. - Thomas Wieder, Nov 27 2007
For n >= 1, a(n) = 1, 2, 6, 24, ... are the positions corresponding to the 1's in decimal expansion of Liouville's constant (A012245). - Paul Muljadi, Apr 15 2008
Triangle A144107 has n! for row sums (given n > 0) with right border n! and left border A003319, the INVERTi transform of (1, 2, 6, 24, ...). - Gary W. Adamson, Sep 11 2008
Equals INVERT transform of A052186: (1, 0, 1, 3, 14, 77,...) and row sums of triangle A144108. - Gary W. Adamson, Sep 11 2008
From Abdullahi Umar, Oct 12 2008: (Start)
a(n) is also the number of order-decreasing full transformations (of an n-chain).
a(n-1) is also the number of nilpotent order-decreasing full transformations (of an n-chain). (End)
n! is also the number of optimal broadcast schemes in the complete graph K_{n}, equivalent to the number of binomial trees embedded in K_{n} (see Calin D. Morosan, Information Processing Letters, 100 (2006), 188-193). - Calin D. Morosan (cd_moros(AT)alumni.concordia.ca), Nov 28 2008
Sum_{n >= 0} 1/a(n) = e. - Jaume Oliver Lafont, Mar 03 2009
Let S_{n} denote the n-star graph. The S_{n} structure consists of n S_{n-1} structures. This sequence gives the number of edges between the vertices of any two specified S_{n+1} structures in S_{n+2} (n >= 1). - K.V.Iyer, Mar 18 2009
Chromatic invariant of the sun graph S_{n-2}.
It appears that a(n+1) is the inverse binomial transform of A000255. - Timothy Hopper (timothyhopper(AT)hotmail.co.uk), Aug 20 2009
a(n) is also the determinant of an square matrix, An, whose coefficients are the reciprocals of beta function: a{i, j} = 1/beta(i, j), det(An) = n!. - Enrique Pérez Herrero, Sep 21 2009
The asymptotic expansions of the exponential integrals E(x, m = 1, n = 1) ~ exp(-x)/x*(1 - 1/x + 2/x^2 - 6/x^3 + 24/x^4 + ... ) and E(x, m = 1, n = 2) ~ exp(-x)/x*(1 - 2/x + 6/x^2 - 24/x^3 + ... ) lead to the factorial numbers. See A163931 and A130534 for more information. - Johannes W. Meijer, Oct 20 2009
Satisfies A(x)/A(x^2), A(x) = A173280. - Gary W. Adamson, Feb 14 2010
a(n) = A173333(n,1). - Reinhard Zumkeller, Feb 19 2010
a(n) = G^n where G is the geometric mean of the first n positive integers. - Jaroslav Krizek, May 28 2010
Increasing colored 1-2 trees with choice of two colors for the rightmost branch of nonleaves. - Wenjin Woan, May 23 2011
Number of necklaces with n labeled beads of 1 color. - Robert G. Wilson v, Sep 22 2011
The sequence 1!, (2!)!, ((3!)!)!, (((4!)!)!)!, ..., ((...(n!)!)...)! (n times) grows too rapidly to have its own entry. See Hofstadter.
The e.g.f. of 1/a(n) = 1/n! is BesselI(0, 2*sqrt(x)). See Abramowitz-Stegun, p. 375, 9.3.10. - Wolfdieter Lang, Jan 09 2012
a(n) is the length of the n-th row which is the sum of n-th row in triangle A170942. - Reinhard Zumkeller, Mar 29 2012
Number of permutations of elements 1, 2, ..., n + 1 with a fixed element belonging to a cycle of length r does not depend on r and equals a(n). - Vladimir Shevelev, May 12 2012
a(n) is the number of fixed points in all permutations of 1, ..., n: in all n! permutations, 1 is first exactly (n-1)! times, 2 is second exactly (n-1)! times, etc., giving (n-1)!*n = n!. - Jon Perry, Dec 20 2012
For n >= 1, a(n-1) is the binomial transform of A000757. See Moreno-Rivera. - Luis Manuel Rivera Martínez, Dec 09 2013
Each term is divisible by its digital root (A010888). - Ivan N. Ianakiev, Apr 14 2014
For m>=3, a(m-2) is the number hp(m) of acyclic Hamiltonian paths in a simple graph with m vertices, which is complete except for one missing edge. For m<3, hp(m)=0. - Stanislav Sykora, Jun 17 2014
a(n) = A245334(n,n). - Reinhard Zumkeller, Aug 31 2014
a(n) is the number of increasing forests with n nodes. - Brad R. Jones, Dec 01 2014
Sum_{n>=0} a(n)/(a(n + 1)*a(n + 2)) = Sum_{n>=0} 1/((n + 2)*(n + 1)^2*a(n)) = 2 - exp(1) - gamma + Ei(1) = 0.5996203229953..., where gamma = A001620, Ei(1) = A091725. - Ilya Gutkovskiy, Nov 01 2016
The factorial numbers can be calculated by means of the recurrence n! = (floor(n/2)!)^2 * sf(n) where sf(n) are the swinging factorials A056040. This leads to an efficient algorithm if sf(n) is computed via prime factorization. For an exposition of this algorithm see the link below. - Peter Luschny, Nov 05 2016
Treeshelves are ordered (plane) binary (0-1-2) increasing trees where the nodes of outdegree 1 come in 2 colors. There are n! treeshelves of size n, and classical Françon's bijection maps bijectively treeshelves into permutations. - Sergey Kirgizov, Dec 26 2016
Satisfies Benford's law [Diaconis, 1977; Berger-Hill, 2017] - N. J. A. Sloane, Feb 07 2017
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 833.
A. T. Benjamin and J. J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A. 2003, id. 125; also p. 90, ex. 3.
A. Berger and T. P. Hill, What is Benford's Law?, Notices, Amer. Math. Soc., 64: 2 (2017), 132-134.
Diaconis, Persi, The distribution of leading digits and uniform distribution mod 1, Ann. Probability, 5, 1977, 72--81,
Douglas R. Hofstadter, Fluid concepts & creative analogies: computer models of the fundamental mechanisms of thought, Basic Books, 1995, pages 44-46.
A. N. Khovanskii. The Application of Continued Fractions and Their Generalizations to Problem in Approximation Theory. Groningen: Noordhoff, Netherlands, 1963. See p.141 (10.19)
D. E. Knuth, The Art of Computer Programming, Vol. 3, Section 5.1.2, p. 623. [From N. J. A. Sloane, Apr 07 2014]
A. P. Prudnikov, Yu. A. Brychkov and O. I. Marichev, "Integrals and Series", Volume 1: "Elementary Functions", Chapter 4: "Finite Sums", New York, Gordon and Breach Science Publishers, 1986-1992.
R. W. Robinson, Counting arrangements of bishops, pp. 198-214 of Combinatorial Mathematics IV (Adelaide 1975), Lect. Notes Math., 560 (1976).
Sepher Yezirah [Book of Creation], circa 300 AD. See verse 52.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Carlo Suares, Sepher Yetsira, Shambhala Publications, 1976. See verse 52.
D. Wells, The Penguin Dictionary of Curious and Interesting Numbers, pp. 102 Penguin Books 1987.
N. J. A. Sloane, The first 100 factorials: Table of n, n! for n = 0..100
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
S. B. Akers and B. Krishnamurthy, A group-theoretic model for symmetric interconnection networks, IEEE Trans. Comput., 38(4), April 1989, 555-566.
Masanori Ando, Odd number and Trapezoidal number, arXiv:1504.04121 [math.CO], 2015.
David Applegate and N. J. A. Sloane, Table giving cycle index of S_0 through S_40 in Maple format [gzipped].
E. Barcucci, A. Del Lungo, R. Pinzani and R. Sprugnoli, La hauteur des polyominos dirigés verticalement convexes, Actes du 31e Séminaire Lotharingien de Combinatoire, Publ. IRMA, Université Strasbourg I (1993).
Jean-Luc Baril, Sergey Kirgizov, Vincent Vajnovszki, Patterns in treeshelves, arXiv:1611.07793 [cs.DM], 2016
M. Bhargava, The factorial function and generalizations, Amer. Math. Monthly, 107 (Nov. 2000), 783-799.
Henry Bottomley, Illustration of initial terms
Douglas Butler, Factorials!
David Callan, Counting Stabilized-Interval-Free Permutations, Journal of Integer Sequences, Vol. 7 (2004), Article 04.1.8.
Peter J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.
Robert M. Dickau, Permutation diagrams
Philippe Flajolet and Robert Sedgewick, Analytic Combinatorics, 2009; see page 18
J. Françon, Arbres binaires de recherche : propriétés combinatoires et applications, Revue française d'automatique informatique recherche opérationnelle, Informatique théorique, 10 no. 3 (1976), pp. 35-50.
H. Fripertinger, The elements of the symmetric group
H. Fripertinger, The elements of the symmetric group in cycle notation
A. M. Ibrahim, Extension of factorial concept to negative numbers, Notes on Number Theory and Discrete Mathematics, Vol. 19, 2013, 2, 30-42.
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 20
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 297
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
M. Janjic, Determinants and Recurrence Sequences, Journal of Integer Sequences, 2012, Article 12.3.5. - N. J. A. Sloane, Sep 16 2012
B. R. Jones, On tree hook length formulas, Feynman rules and B-series, p. 22, Master's thesis, Simon Fraser University, 2014.
Clark Kimberling, Matrix Transformations of Integer Sequences, J. Integer Seqs., Vol. 6, 2003.
G. Labelle et al., Stirling numbers interpolation using permutations with forbidden subsequences, Discrete Math. 246 (2002), 177-195.
Wolfdieter Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4.
John W. Layman, The Hankel Transform and Some of its Properties, J. Integer Sequences, 4 (2001), #01.1.5.
Paul Leyland, Generalized Cullen and Woodall numbers
Peter Luschny, Swing, divide and conquer the factorial, (excerpt).
Rutilo Moreno and Luis Manuel Rivera, Blocks in cycles and k-commuting permutations, arXiv:1306:5708 [math.CO], 2013-2014.
T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176. [Annotated, scanned copy]
N. E. Nørlund, Vorlesungen ueber Differenzenrechnung Springer 1924, p. 98.
R. Ondrejka, 1273 exact factorials, Math. Comp., 24 (1970), 231.
Enrique Pérez Herrero, Beta function matrix determinant Psychedelic Geometry blogspot-09/21/09
Alexsandar Petojevic, The Function vM_m(s; a; z) and Some Well-Known Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7
Fred Richman, Multiple precision arithmetic(Computing factorials up to 765!)
Luis Manuel Rivera, Integer sequences and k-commuting permutations, arXiv preprint arXiv:1406.3081 [math.CO], 2014-2015.
Michael Z. Spivey and Laura L. Steil, The k-Binomial Transforms and the Hankel Transform, Journal of Integer Sequences, Vol. 9 (2006), Article 06.1.1.
R. P. Stanley, A combinatorial miscellany
R. P. Stanley, Recent Progress in Algebraic Combinatorics, Bull. Amer. Math. Soc., 40 (2003), 55-68.
Einar Steingrimsson and Lauren K. Williams, Permutation tableaux and permutation patterns, arXiv:math/0507149 [math.CO], 2005-2006.
A. Umar, On the semigroups of order-decreasing finite full transformations, Proc. Roy. Soc. Edinburgh 120A (1992), 129-142.
G. Villemin's Almanach of Numbers, Factorielles Sage Weil, The First 999 Factorials
Eric Weisstein's World of Mathematics, Factorial, Gamma Function, Multifactorial, Permutation, Permutation Pattern, Laguerre Polynomial, Diagonal Matrix, Chromatic Invariant.
R. W. Whitty, Rook polynomials on two-dimensional surfaces and graceful labellings of graphs, Discrete Math., 308 (2008), 674-683.
Wikipedia, Factorial
D. Zeilberger, King Solomon and Rabbi Ben Ezra's Evaluations of Pi and Patriarch Abraham's Analysis of an Algorithm.
Index entries for "core" sequences
Index to divisibility sequences
Index entries for sequences related to factorial numbers
Index entries for sequences related to Benford's law
Exp(x) = Sum_{m >= 0} x^m/m!. - Mohammad K. Azarian, Dec 28 2010
Sum_{i=0..n} (-1)^i * i^n * binomial(n, i) = (-1)^n * n!. - Yong Kong (ykong(AT)curagen.com), Dec 26 2000
Sum_{i=0..n} (-1)^i * (n-i)^n * binomial(n, i) = n!. - Peter C. Heinig (algorithms(AT)gmx.de), Apr 10 2007
The sequence trivially satisfies the recurrence a(n+1) = Sum_{k=0..n} binomial(n,k) * a(k)*a(n-k). - Robert FERREOL, Dec 05 2009
a(n) = n*a(n-1), n >= 1. n! ~ sqrt(2*Pi) * n^(n+1/2) / e^n (Stirling's approximation).
a(0) = 1, a(n) = subs(x = 1, diff(1/(2-x), x$n)), n = 1, 2, ... - Karol A. Penson, Nov 12 2001
E.g.f.: 1/(1-x).
a(n) = Sum_{k=0..n} (-1)^(n-k)*A000522(k)*binomial(n, k) = Sum_{k=0..n} (-1)^(n-k)*(x+k)^n*binomial(n, k). - Philippe Deléham, Jul 08 2004
Binomial transform of A000166. - Ross La Haye, Sep 21 2004
a(n) = Sum_{i=1..n} ((-1)^(i-1) * sum of 1..n taken n - i at a time) - e.g., 4! = (1*2*3 + 1*2*4 + 1*3*4 + 2*3*4) - (1*2 + 1*3 + 1*4 + 2*3 + 2*4 + 3*4) + (1 + 2 + 3 + 4) - 1 = (6 + 8 + 12 + 24) - (2 + 3 + 4 + 6 + 8 + 12) + 10 - 1 = 50 - 35 + 10 - 1 = 24. - Jon Perry, Nov 14 2005
a(n) = (n-1)*(a(n-1) + a(n-2)), n >= 2. - Matthew J. White, Feb 21 2006
1 / a(n) = determinant of matrix whose (i,j) entry is (i+j)!/(i!(j+1)!) for n > 0. This is a matrix with Catalan numbers on the diagonal. - Alexander Adamchuk, Jul 04 2006
Hankel transform of A074664. - Philippe Deléham, Jun 21 2007
For n >= 2, a(n-2) = (-1)^n*Sum_{j=0..n-1} (j+1)*stirling1(n,j+1). - Milan Janjic, Dec 14 2008
From Paul Barry, Jan 15 2009: (Start)
G.f.: 1/(1-x-x^2/(1-3x-4x^2/(1-5x-9x^2/(1-7x-16x^2/(1-9x-25x^2....(continued fraction), hence Hankel transform is A055209.
G.f. of (n+1)! is 1/(1-2x-2x^2/(1-4x-6x^2/(1-6x-12x^2/(1-8x-20x^2.... (continued fraction), hence Hankel transform is A059332. (End)
a(n) = Prod_{p prime} p^{Sum_{k > 0} [n/p^k]} by Legendre's formula for the highest power of a prime dividing n!. - Jonathan Sondow, Jul 24 2009
a(n) = A053657(n)/A163176(n) for n > 0. - Jonathan Sondow, Jul 26 2009
It appears that a(n) = (1/0!) + (1/1!)*n + (3/2!)*n*(n-1) + (11/3!)*n*(n-1)*(n-2) + ... + (b(n)/n!)*n*(n-1)*...*2*1, where a(n) = (n+1)! and b(n) = A000255. - Timothy Hopper, Aug 12 2009
a(n) = a(n-1)^2/a(n-2) + a(n-1), n >= 2. - Jaume Oliver Lafont, Sep 21 2009
a(n) = Gamma(n+1). - Enrique Pérez Herrero, Sep 21 2009
a(n) = A_{n}(1) where A_{n}(x) are the Eulerian polynomials. - Peter Luschny, Aug 03 2010
a(n) = n*(2*a(n-1) - (n-1)*a(n-2)), n > 1. - Gary Detlefs, Sep 16 2010
1/a(n) = -Sum_{k=1..n+1} (-2)^k*(n+k+2)*a(k)/(a(2*k+1)*a(n+1-k)). - Groux Roland, Dec 08 2010
From Vladimir Shevelev, Feb 21 2011: (Start)
a(n) = Product_{p prime, p <= n} p^(Sum_{i >= 1} floor(n/p^i);
The infinitary analog of this formula is: a(n) = prod{q terms of A050376 <= n} q^((n)_q), where (n)_q denotes the number of those numbers <=n for which q is an infinitary divisor (for the definition see comment in A037445). (End)
The terms are the denominators of the expansion of sinh(x) + cosh(x). - Arkadiusz Wesolowski, Feb 03 2012
G.f.: 1 / (1 - x / (1 - x / (1 - 2*x / (1 - 2*x / (1 - 3*x / (1 - 3*x / ... )))))). - Michael Somos, May 12 2012
G.f. 1 + x/(G(0)-x) where G(k) = 1 - (k+1)*x/(1 - x*(k+2)/G(k+1)); (continued fraction, 2-step). - Sergei N. Gladkovskii, Aug 14 2012
G.f.: W(1,1;-x)/(W(1,1;-x) - x*W(1,2;-x)), where W(a,b,x) = 1 - a*b*x/1! + a*(a+1)*b*(b+1)*x^2/2! -...+ a*(a+1)*...*(a+n-1)*b*(b+1)*...*(b+n-1)*x^n/n! +...; see [A. N. Khovanskii, p. 141 (10.19)]. - Sergei N. Gladkovskii, Aug 15 2012
From Sergei N. Gladkovskii, Dec 26 2012. (Start)
G.f.: A(x) = 1 + x/(G(0) - x) where G(k) = 1 + (k+1)*x - x*(k+2)/G(k+1); (continued fraction).
Let B(x) be the g.f. for A051296, then A(x) = 2 - 1/B(x).(End)
G.f.: 1 + x*(G(0) - 1)/(x-1) where G(k) = 1 - (2*k+1)/(1-x/(x - 1/(1 - (2*k+2)/(1-x/(x - 1/G(k+1) ))))); (continued fraction). - Sergei N. Gladkovskii, Jan 15 2013
G.f.: 1 + x*(1 - G(0))/(sqrt(x)-x) where G(k) = 1 - (k+1)*sqrt(x)/(1-sqrt(x)/(sqrt(x)-1/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jan 25 2013
G.f.: 1 + x/G(0) where G(k) = 1 - x*(k+2)/( 1 - x*(k+1)/G(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Mar 23 2013
a(n) = det(S(i+1, j), 1 <= i, j <=n ), where S(n,k) are Stirling numbers of the second kind. - Mircea Merca, Apr 04 2013
G.f.: G(0)/2, where G(k) = 1 + 1/(1 - x*(k+1)/(x*(k+1) + 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 24 2013
G.f.: 2/G(0), where G(k) = 1 + 1/(1 - 1/(1 - 1/(2*x*(k+1)) + 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, May 29 2013
G.f.: G(0), where G(k) = 1 + x*(2*k+1)/(1 - x*(2*k+2)/(x*(2*k+2) + 1/G(k+1))); (continued fraction). - Sergei N. Gladkovskii, Jun 07 2013
a(n) = P(n-1, floor(n/2)) * floor(n/2)! * (n - (n-2)*((n+1) mod 2)), where P(n, k) are the k-permutations of n objects, n > 0. - Wesley Ivan Hurt, Jun 07 2013
a(n) = a(n-2)*(n-1)^2 + a(n-1), n > 1. - Ivan N. Ianakiev, Jun 18 2013
a(n) = a(n-2)*(n^2-1) - a(n-1), n > 1. - Ivan N. Ianakiev, Jun 30 2013
G.f.: 1 + x/Q(0),m=+2, where Q(k) = 1 - 2*x*(2*k+1) - m*x^2*(k+1)*(2*k+1)/( 1 - 2*x*(2*k+2) - m*x^2*(k+1)*(2*k+3)/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Sep 24 2013
a(n) = Product_{i = 1..n} A014963^[n/i] = Product_{i = 1..n} A003418([n/i]), where [n] denotes the floor function. - Matthew Vandermast, Dec 22 2014
a(n) = round(Sum_{k>=1} log(k)^n/k^2), for n>=1, which is related to the n-th derivative of the Riemann zeta function at x=2 as follows: round((-1)^n * zeta^(n)(2)). Also see A073002. - Richard R. Forberg, Dec 30 2014
a(n) ~ Sum_{j>=0} j^n/e^j, where e = A001113. When substituting a generic variable for "e" this infinite sum is related to Eulerian polynomials. See A008292. This approximation of n! is within 0.4% at n = 2. See A255169. Accuracy, as a percentage, improves rapidly for larger n. - Richard R. Forberg, Mar 07 2015
a(n) = Product_{k=1..n} (C(n+1, 2)-C(k, 2))/(2*k-1); see Masanori Ando link. - Michel Marcus, Apr 17 2015
a(2^n) = 2^(2^n - 1) * 1!! * 3!! * 7!! * ... * (2^n - 1)!!. For example, 16! = 2^15*(1*3)*(1*3*5*7)*(1*3*5*7*9*11*13*15) = 20922789888000. - Peter Bala, Nov 01 2016
There are 3! = 1*2*3 = 6 ways to arrange 3 letters {a, b, c}, namely abc, acb, bac, bca, cab, cba.
Let n = 2. Consider permutations of {1, 2, 3}. Fix element 3. There are a(2) = 2 permutations in each of the following cases: (a) 3 belongs to a cycle of length 1 (permutations (1, 2, 3) and (2, 1, 3)); (b) 3 belongs to a cycle of length 2 (permutations (3, 2, 1) and (1, 3, 2)); (c) 3 belongs to a cycle of length 3 (permutations (2, 3, 1) and (3, 1, 2)). - Vladimir Shevelev, May 13 2012
G.f. = 1 + x + 2*x^2 + 6*x^3 + 24*x^4 + 120*x^5 + 720*x^6 + 5040*x^7 + ...
A000142 := n->n!; [ seq(n!, n=0..20) ];
spec := [ S, {S=Sequence(Z) }, labeled ]; [seq(combstruct[count](spec, size=n), n=0..20)];
# Maple program for computing cycle indices of symmetric groups
M:=40: f:=array(0..M): f[0]:=1: lprint("n= ", 0); lprint(f[0]); f[1]:=x[1]: lprint("n= ", 1); lprint(f[1]); for n from 2 to M do f[n]:=expand((1/n)*add( x[l]*f[n-l], l=1..n)); lprint("n= ", n); lprint(f[n]); od:
with(combstruct):ZL0:=[S, {S=Set(Cycle(Z, card>0))}, labeled]: seq(count(ZL0, size=n), n=0..20); # Zerinvary Lajos, Sep 26 2007
Table[Factorial[n], {n, 0, 20}] (* Stefan Steinerberger, Mar 30 2006 *)
FoldList[#1 #2 &, 1, Range@ 20] (* Robert G. Wilson v, May 07 2011 *)
Range[20]! (* Harvey P. Dale, Nov 19 2011 *)
RecurrenceTable[{a[n] == n*a[n - 1], a[0] == 1}, a, {n, 0, 22}] (* Ray Chandler, Jul 30 2015 *)
(Axiom) [factorial(n) for n in 0..10]
(MAGMA) a:= func< n | Factorial(n) >; [ a(n) : n in [0..10]];
(Haskell)
a000142 :: (Enum a, Num a, Integral t) => t -> a
a000142 n = product [1 .. fromIntegral n]
a000142_list = 1 : zipWith (*) [1..] a000142_list
-- Reinhard Zumkeller, Mar 02 2014, Nov 02 2011, Apr 21 2011
(Python)
for i in range(1, 1000):
....y=i
....for j in range(1, i):
.......y=y*(i-j)
.......print(y, "\n")
import math
....math.factorial(i)
....print("")
# Ruskin Harding, Feb 22 2013
(PARI) a(n)=prod(i=1, n, i) \\ Felix Fröhlich, Aug 17 2014
(PARI) a(n)=n! \\ Felix Fröhlich, Aug 17 2014
(Sage) [factorial(n) for n in (1..22)] # Giuseppe Coppoletta, Dec 05 2014
Cf. A000165, A001044, A001563, A003422, A009445, A010050, A012245, A033312, A034886, A038507, A047920, A048631.
Factorial base representation: A007623.
Cf. A003319, A052186, A144107, A144108. - Gary W. Adamson, Sep 11 2008
Complement of A063992. - Reinhard Zumkeller, Oct 11 2008
Cf. A053657, A163176. - Jonathan Sondow, Jul 26 2009
Cf. A173280. - Gary W. Adamson, Feb 14 2010
Boustrophedon transforms: A230960, A230961.
Cf. A233589.
Cf. A245334.
A row of the array in A249026.
Cf. A001013 (multiplicative closure).
For factorials with initial digit d (1 <= d <= 9) see A045509, A045510, A045511, A045516, A045517, A045518, A282021, A045519; A045520, A045521, A045522, A045523, A045524, A045525, A045526, A045527, A045528, A045529.
Sequence in context: A133942 A159333 A165233 * A074166 A130641 A129655
Adjacent sequences: A000139 A000140 A000141 * A000143 A000144 A000145
core,easy,nonn,nice
N. J. A. Sloane
approved | https://oeis.org/A000142 | CC-MAIN-2017-13 | refinedweb | 4,491 | 69.28 |
Now, for Problem 87, I used D, which I had just recently freed up, having not used it since my initial solution to problem 22. D is a fine language with C-like syntax which compiles directly to native code and lets you do all sorts of stuff that one would want to do in a low or high level language...its a powerful language, which was a nice breath of fresh air having just come from SwiftScript. Problems 87 is rather simple problem: "how many numbers below 50000000 can be expressed as the sum of a prime square, prime cube, and prime fourth power?": the main issue comes in finding a way to solve it efficiently, which I did by storing all square+cube sums in a set (implemented by hand as an array of bits) and then checking against this set to add in the fourth powers. This was much more efficient than my first solution, which, without going into too many details, took 5min to run.
Other than that, the only issue I had was that I trusted myself too much with my prime sieve. I wrote it from memory based on one I have written in python a number of times, but I made a few small mistakes the first couple of times around that caused it to not quite find all the primes. Of course, this in turn led to some difficulties. However, once I discovered that annoying little error, everything fell into place. Solution runs in 10 seconds on my machine.
import std.stdio; import std.math; import std.conv; /** Writing all the casts is annoying */ int isqrt(int x) { return to!int(floor(sqrt(to!float(x)))); } /** "Basic" Prime Sieve */ int[] sieve(int bound) { int[] partial; int rbound = isqrt(bound); if (bound < 11) { return [2, 3, 5, 7]; } else { partial = sieve(rbound); } int current = rbound; if (current % 2 == 0) { current += 1; } int[] newprimes = partial; while (current < bound) { bool isprime = true; int rcurrent = isqrt(current); foreach (p; partial) { if (p > rcurrent) { break; } if (current % p == 0) { isprime = false; break; } } if (isprime) { newprimes ~= current; } current += 2; } return newprimes; } int BOUND = 50000000; /**Set implemented with array of bits Not only done for space efficiency, D does not allow static arrays with 50000000 elements (at least by default). */ uint[50000000/32 + 1] is23sum; void setIsSum(int elem) { if (!isSum(elem)) { is23sum[elem / 32] += 1 << (elem % 32); } } bool isSum(int elem) { return ((is23sum[elem / 32] >> (elem % 32)) & 1) > 0; } void main() { // Get all necessary primes int[] primes = sieve(isqrt(BOUND)); // Precompute arrays int[] primes2; foreach (p ; primes ) { primes2 ~= pow(p , 2); } int[] primes3; foreach (p ; primes ) { int temp = pow(p, 3); if (temp > BOUND) { break; } else { primes3 ~= temp; } } int[] primes4; foreach (p; primes) { int temp = pow(p, 4); if (temp > BOUND) { break; } else { primes4 ~= temp; } } is23sum[] = 0; // Precompute all numbers that are sums of squares and cubes foreach (p2; primes2) { foreach (p3; primes3) { int s = p2 + p3; if (s < BOUND) { setIsSum(s); } } } int ans = 0; // Checking for sum of square, cube, and 4th power foreach(i; 27 .. BOUND) { foreach (p4; primes4) { if ( (i - p4) < 12) { break; } else if (isSum(i - p4)) { ans = ans + 1; break; } } } writeln(ans); } | http://pelangchallenge.blogspot.com/2014/06/ | CC-MAIN-2020-29 | refinedweb | 529 | 68.84 |
import java.util.* fun main(args: Array<String>) { val reader = Scanner(System.`in`) print("Enter two numbers: ") // nextDouble() reads the next double from the keyboard val first = reader.nextDouble() val second = reader.nextDouble() print("Enter an operator (+, -, *, /): ") val operator = reader.next()[0] val result: Double when (operator) { '+' -> result = first + second '-' -> result = first - second '*' -> result = first * second '/' -> result = first / second // operator doesn't match any case constant (+, -, *, /) else -> { System.out.printf("Error! operator is not correct") return } } System.out.printf("%.1f %c %.1f = %.1f", first, operator, second, result) }
When you run the program, the output will be:
Enter two numbers: 1.5 4.5 Enter an operator (+, -, *, /): * 1.5 * 4.5 = 6.8
The
* operator entered by the user is stored in the operator variable using the
next() method of
Scanner object.
Likewise, the two operands, 1.5 and 4.5 are stored in variables first and second respectively using the
nextDouble() method of
Scanner object.
Since, the operator
* matches the when condition
'*':, the control of the program jumps to
result = first * second;
This statement calculates the product and stores in the variable result and it is printed using the
printf statement.
Here's the equivalent Java code: Java Program to Make a Simple Calculator | https://cdn.programiz.com/kotlin-programming/examples/calculator-when | CC-MAIN-2019-47 | refinedweb | 204 | 50.12 |
Have you ever wanted to turn a .ASCX file into a distributable control? This program generates the source code for an .ASCX file so that you can compile it without having to distribute the .ASCX file. It comes close to simulating how the Page.LoadControl ("asdf.ascx") works.
CDefaultand the namespace was left as ASP):
//======================================================= private void Page_Load(object sender, System.EventArgs e) { // Put user code to initialize the page here Control c = new ASP.CDefault(); this.Controls.Add ( C ); } //=======================================================
string[]). The parser can't tell if a property is a list because it can't always do reflection on the type (any ideas how to fix this?).
If you like it, please send an email to bvk@villagechief.com
If you make any changes or additions, please send them to me at the above email address.
This is freeware to do with as you see fit. The author accepts no responsibility for any damage or data loss caused by this program.
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His life and Works
SOHEIL
M. AFNAN
Ph.D. (Cantab.)
Ruskin House
GEORGE ALLEN & UNWIN LTD
MUSEUM STREET LONDON
.~''/.5/
T- --
, .~ 7A(P
FIRST PUBLISHED IN
1958
This haole is copyrig"t under tlu Berne Convention. Apart from any fair dealing for tlu purposes of private study, research, criticism or review, as permitted under t"e Copyrig"t Act 1956, no portion may he reproduced hy any process without written permission. Enquiry should he made to t"e puhlis"ers
PREFACE
THIS
is an attempt to present to the general reader the life and works
©
George Allen and Unwin Ltd., 1958
of A vicenna, who is beyond doubt the most provocative figure in the history of thought in the East. It is not a defence of him and his system, nor a critique of his philosophy. was deliberately scornful of defenders During his lifetime he and critics alike; he could
not think better of them now that a thousand years have gone by. With his position amply justified, and after that extended period when his name hung on the lips of physicians and philosophers from the borders of China to the cloisters of mediaeval Paris and Oxford, it seems best to let him speak for himself. The painted frieze only lately discovered Western world. We have felt no temptation to adapt him to modem thought; or to graft his conceptions on to those that belong distinctively to an experimental age. We have wished to give the right historical perspective, and to show him as the product of the impact of Greek thought on Islamic teachings against the background Renaissance in the tenth century. The legitimate question whether there is anything of permanent value in his thought has been emphasized
Printed in Great Britain in t a-point Fournier type
BY UNWIN WOKING BROTHERS AND LIMITED LONDON
behind a coating of plaster at the that he is no newcomer to the
Bodleian, is sufficient evidence
of the Persian
has been left for the reader to decide. Yet it that the problems he was confronted with
resulted from the conflicting disciplines of two separate cultures brought face to face. He is therefore of more than historical interest. His attitude can be of guidance to those in the East who are meeting the challenge of Western civilization; and to those in the West who have yet to find a basis on which to harmonize spiritual values. scientific with
5
AVICENNA
There remains the pleasant task of expressing our thanks to Dr S. Pines with whom we have discussed Avicenna frequently,and who has read some of me chapters of this book, and made valuable suggestions. s. M. AFNAN
Pembrolce CeOege, Cambridge, July 1956
PREFACE
CONTENTS
page
5
Introduction
I
9
39 57 83
Persia in the Tenth Century Life and Works of Avicenna Problems of Logic Problems qf Metaphysics of Psychology
II III IV
106
136 168 201 233 258 289 291 SUCCESSORS 295 297
'ilProblems
VI VII VIII IX
Problems of Religion Medicine and the Natural Sciences Avicenna and the East Avicenna and the West
CONCLUSION SELECTED BIBLIOGRAPHY CHRONOLOGY OF AVICENNA'S AND COMMENTATORS INDEX
6
Harlin al-Rashid who reigned after him established the library known as the KhQ{f1nat al-lfilcma (The Treasure-house of Wisdom) under the direction of competent and earnest scholars. It led to the unhappy Shu'iibiyya movement with its emphasis on the superiority of the non-Arab races. proved eminently fruitful. All mixed freely and joined in an earnest quest for knowledge. 775) added to his liberal outlook a deep love of learning. An unfortunate consequence of this was that racial rivalry reappeared. The Caliphs themselves set the pace. the Christian Syriacs their . They had done most to establish the new regime. they had much experience to offer in the field of administration and State finance. and members of all the nations involved made vital contributions. linguistic versatility. the Persians their culture and sense of history. The Arabs contributed a high sense of mission. Their newly-founded capital had gathered together men from distant countries.INTRODUCTION factors helped to introduce the remarkable 'Abbasid Age under the aegis of the Caliphs of Baghdad. and the stimulating elan of Islam was everywhere at work. AI-Man~iir (d. nevertheless. the Harranians their Hellenistic heritage and the Indians their ancient lore. and they consequently filled many of the government posts. All branches of art and literature flourished as never before or since in the Islamic world. Material prosperity enabled the people to take an increasing interest in cultural MANY A* 9 . leading to occasional violence and bloodshed. The Persians became particularly favoured. The change from the Umayyads of Damascus and their tribal loyalties held fresh promise for the non-Arabs who had adopted the new Faith. A new civilization was being created. It was a case of religion uniting people and giving purpose and direction to their lives. The association.
Public and private libraries began to multiply.) it developed in the form of court-literature and belles-lettres. which might from the political point of view be considered the beginning of that general decline in the fortunes of the 'Abbasids. mostly Persians. entirely distinct from one anal her. A. chosen and the common classes. It has been possible to show3 that some of the happiest philosophical terms in Arabic that are not of Qur'anic origin. describing the duties of the monarch to his people and rhe proper procedure at court. p. and the suitable policy towards the governed .> With the establishment of the 'Abbasid Caliphate in 750 (132. IfY. 10 II . Together with epistolary and court-literature came belles-lettres. The Caliphs from the time of Umayyad Hisham realized the necessity of some guide to help them to formalize their relations with the various communities they were now to rule..5 Thus inspired. Afnan: Greek Philosophical Terms and Their Arahic and Persian Equivalents. are first met with in his writings and are presumably of his coining. edit. Professor Gibb remarks that 'in the second century therefore there were in 'iraq two schools of Arabic letters. animated by a different spirit. Miss Pinto: La BibliothechB degli Arahi ••• Bihliofilia.t~: Kitiih al-Tiij ••• . S.'4 It was. p. The outstanding writer in this genre. Zaki. and almost entirely negative towards each other. 242. p. II7. p. poetry took forms hitherto not attempted. to be known as adab. There was an intensive study of the Arabic language and grammar. 243.AVICENNA INTRODUCTION pursuits. It first appeared in the late Umayyad period in Syria and 'Iraq.H. p.\<t:i also perhaps the earliest to introduce Aristotelian Logic to the Islamic worlds This author has grown in stature since modem scholarship began to devote attention to him and recognize the valuable services that he rendered to the Arabic language. 1928. At first it was used for correspondence concerned with the administration of the new Empire and the organization of secretarial offices. 833). a school-master who rose to high office under the Umayyads. and was created by Muslims of foreign extraction. 220.' and high prices were paid for manuscripts. Discussing this aspect of Arabic literature and the advent of secular prose. serving different purposes. borrowed by the translators and philosophers alike... 4 Social Significance of the Shu'iihiya. 5 Fihrist. In the field of thought there was the emergence of a rationalistic school of theologians who came to be known as the Mu'tazelites and whose views eventually influenced profoundly some of the Islamic philosophers. Its chief exponent was 'Abd al-Hamid al-Katib.. This they found in the court-literature of the erstwhile Sasanian Empire which although at the time of its conquest was hopelessly divided within itself. Rules of prosody were laid down and carefully studied. • Fihrist. he <. however. Ibn al-Qifp. deeply impressed the Arab conquerors by its outward majesty and efficient system of administration. al-Ma'miin sent groups of scholars to Asia Minor and Cyprus to bring back Greek books. the organization of the I Cf. In literature there was the gradual development of an as yet hardly existing secular prose as distinct from the purely religious. during the Caliphate of al-Ma'miin (d. XXX. if not its actual originator. was Ibn al-Muqaffa' (killed in early age).'1 Consequently the secretarial kiitibs undertook the translation of some of these Persian court-books. already associated with the two rival schools of Kufa and Basra. He wrote to I Jal. p. or the mystical or even the Mu'tazelite style of writing and terminology. The whole corpus of pre-Islamic poetry including some of doubtful authenticity came to be recorded. 'It was from them [the Persians] that we took the methods of royalty and government. Pederson. His special interest in foreign culture and philosophy is commemorated in the story that Aristotle appeared to him in a dream and spoke words of encouragement to him. Studia . • Fihrist. This secular prose was to become the model of Arabic philosophical language and a chief source of its technical terms. 3 Cf. One of the creators of Arabic secular prose.• . that learning flourished most. 23. A. Two factors were to prove of great importance to the subject of our inquiry. deriving from different sources.
243. Usaihi'a. 143. Tawl}idi: 3 Muqiiksat. This is not to say that Islamic philosophy is a sterile hybrid denied the capacity to produce any characteristic thought of its own. and still another to the Stoics and the thinkers of the Hellenistic age. as their name shows. and the heated discussions that took place there. differed I Fihrln. and the Emperor after some hesitation complied. and Hunain arrived in Syria to study Greek and search for books to take back with him. 206. and he lavishly rewarded poets. • I. and for their company. 274. The sources of Islamic philosophy are not far to seek. held meetings and. They also were authors themselves. 238. Neo-Platonic. p. The general intellectual climate of this time is typified by the literary and philosophical gatherings in the homes of wealthy patrons or learned men. Very engaging accounts of these have survived in the writings of an unappreciated but gifted litdrateur» Men went on journeys in search of knowledge. p. we are told. occupied with the problems . 2 The Nowbakht family. And many books were translated in his name. became perhaps the most famous patrons of literature in Baghdad. were enterprising enough to help their wealthy friends to start private libraries.of analysis. It is only to stress the contrast with Greek philosophy as a secular discipline. and addressing itself to a people with a common culture and heritage." And Zayyat. Manichaean. The term philosophy has admittedly had different connotations at various periods of history and in various parts of the world. This is as true today as it was many centuries ago. a 4 Qifp. although primarily concerned with government and administration. less interested in politics. Al-Ma'miin also made the old medical and philosophical school of Gundishapur in southern Persia the object of his special care. the son of an olive-oil merchant of Tabaristan.4 and himself wrote a detailed commentary on the De Generatione et Corruptione of Aristotle. 13 . did not fail in the patronage of literature. The main stream comes from classical Greece. It was in this brilliant milieu. Gnostic. at a time when the age of Arabic prose and poetry was approaching its zenith. Hermetic and other ideas proceeding from the different schools that flourished in the late Hellenistic age. I. but they are numerous and complex. were interested in astronomy. pp. To these were added varying measures of Stoic. not much influenced by foreign and conflicting views. another to Aristotle. It is not surprising therefore that what actually developed in Baghdad during the 'Abbasid Caliphate. His 'bounties to the translators and copyists was nearly two thousand dinars every month. were distinguished authors themselves. 177. One of them 'entertained a group of those who translated books on philosophy' .'> There were also some Arabs equally interested and enthusiastic about the new learning. with a strong current of Muslim religious thought associated with the Mutakallemun and the Mu'tazelites. scholars. and supported those who translated from Greek.3 Furthermore they held regular meetings in their homes at which religious as well as literary subjects were discussed. It may well be asked whether there is such a thing as Islamic philosophy proper. linguists hastened to the heart of Arabia to learn the pure tongue. p.AVICENNA INTRODUCTION the Emperor of Byzantium asking him to send some of those fine collections of Greek learning that were still stored and treasured in his country. 'they used to provide for a group of translators ••• about five hundred dinars per month for translations. * * * * Ice. translated books from Persian. that Islamic philosophy began to take shape with a free and vigorous exercise of reason. geographers went to visit the lands conquered by Islam. The generous support of literary men by the Caliphs set an example to the members of certain old and well-known families who had attained power and wealth. 177. paid thousands of dirhams to medical men and translators of books. A. Vol. who became the vizier to three different Caliphs. not synthesis. The Barmakids. Philosophy meant one thing to the pre-Socratics. and translators.. Ihitl. p. The Munajjim (astronomer) family who. Imme• 12 Filarist.
Vol. and the reconciliation of Greek thought with the tenets of Islam.AVICENNA INTRODUCTION materially from the classical conception of that subject. and based on the general principles of the Greek discipline. and when the Arabs conquered Egypt. It will be noted that almost all the translators of Greek works into Arabic were Christians. Christian philosophy in the Middle Ages. Meyerhof: Von Alexandria nach Baghdad.. To them must be added a few notable translators from the Sabean community of Harran who rendered valuable services particularly in the translation of Greek mathematical texts into Arabic. Farabi does not say why. Usaibi'a. The language of the Church was Greek and religious problems were debated in that language with the support of classical learning and philosophy. far more than is generally conceded. the Nestorians. and Nestorian. logically argued.'2 After a stay in his home town. and kept there for a long period. In outlook it was deeply influenced by Stoic and Neo-Platonic thought in addition to the thought of classical Greece. Although Syriac translators from the Greek had been active even before the schism. Jacobite or Monophysite. It was headed by St Ephraim. to break away from the other two : Churches. they were either Muslims by birth or converts from Christianity. 2. The teaching of classical philosophy from its source in Athens established itself in the museia and academies of Alexandria. led through the Christian I Cf. A. communities of Syria and northern 'Iraq. In opposition to the pagan origin of the school of Alexandria and in imitation of it. even while attempting to harmonize it with the fundamentals of religion. while those of the Monophysites were Alexandria. p.D. Bishop Jacob founded a school at Nisibis. But it was philosophy inasmuch as it aimed at the establishment of a system rationally conceived. perhaps because the students and teachers were mostly from that country. however. thereby stimulating if not actually originating that movement. And it was in tum to influence. Eustathius. Their centres were at Nisibis. the first went to teach in Baghdad. helped the development of the Syriac language by the translation of many important works. including those of Aristotle. • I. Furthermore their chief aim was the application of reason to revelation.2 The institution became known as the school of the Persians. Not until mediaeval Europe and the rise of Scholasticism. these institutions were still flourishing. it was later transferred to Edessa. and Zoroastrianism. thus making it a Hellenizing institution. Hippocrates and Galen. None of the Christian thinkers of Baghdad grew to the same stature. but he is quoted to the effectI that 'it was transferred from Alexandria to Antioch. The chief route of Greek learning. and Farabi studied Greek philosophy under a pupil of the latter by the name of Ibn Hailan. and since the second century centre of Christianity in 'Iraq.Ecole d'Alexandrie. Bishop of Antioch. nevertheless the term Islamic philosophy is justified because although its outstanding figures were often of different countries. Edessa Seleucia on Tigris and Gundishapiir. capital of Osrohene. Two others studied with him. The schism which broke up the Eastern Church into Orthodox or State Church. a noted poet and theologian in Syriac. founded a school there not long after the Council of Nicea in A. Matter: Histoire de [. It was from these towns and from their convents that some Syriacs moved to Baghdad to teach and to translate Greek classical learning into their mother-tongue and into Arabic. 325. not to mention minor places. until it was superseded by the more virile and resourceful Arabic. Because of political uncertainties. Judaism. I Barhadsabba 'Arbaya: Cause • Cf. de la Fondation des Ecoles. until there was only one man to teach it. Cf. and there were a few who wrote philosophical treatises of their own. 14 . Greek learning reached Baghdad by different routes. . do we find a corresponding in tellectual effort. Antioch and Amida. The second also eventually left Persia for the same destination. one was from Harran [Carrhae] and the other from Marw . I And soon after. had important literary consequences for the Aramean world. Hayes: L'Ecole d'Edesse.. as well as writings by the Christian Fathers. . 135.
The Caliphal-Ma'mun infuriated orthodoxy by publicly joining them. 5 Edit. but their religious views became the official theology of the 'Abbasids for a hundred years.Itwas therefore only natural and necessary for them to devote equal attention to the often conflicting principles of the two disciplines. IV. nor always very liberal. 3 Cf. 4 Land: Anecdoton Syriacorum. The significance of the term lealtim. nor free-thinkers. Although these were intellectually inclined. and that justifies the supposition in doubtful cases that these influences were in fact operative. Greek. the Kiuib al-Fihrist composed in 987 gives us valuable information about the extent to which Greek learning was rendered into Arabic. have been recorded. p. Vol. Neo-Platonic and other currents in Islamic philosophy. 3 Cf. 1389.'. Vol. and had considerable influence on the climate .s • It applies to all those who followed the Greek discipline as distinct from the religious. As regards Stoic. This institution had very much declined by the time of the early 'Abbasid Caliphs.of thought at the time. have remained. it shows that Greek scientific.S. Bywater: Supplementum Aristotelium. and themselves had received a thorough training in the tenets of their Faith. 2. The currents of orthodox and Mu'tazelite religious thought are explained by the fact that the Faliisifol were true Muslims even though unable to subscribe to all the dogmas expounded by the theologians of the time. I. • Tiirilr:A al-/fulcamii'. and the Beirut copy in that of his son.. Vol. z98. * * * * With Hunain (Ioanitus) as the central and dominating figure. Col. :2. Source-book for almost all our knowledge of the works written and translated in Baghdad. and attempted to explain all things rationally.AVICENNA INTRODUCTION There was still another route to which some reference has already been made above. Nallino: R. Furthermore their fundamental problem-sometimes called the scholastic problem-s-was the reconciliation of religion and philosophy. Although one scholar has entertained doubts. VII. it is hardly disputable that Ibn al-Muqaffa' did translate some parts of Aristotle's Organon from the Persian (presumably in its Pahlawi form).5 Yet another route by which Greek learning reached Baghdad and the Islamic world was by way of the medico-philosophical school of Gundishapur in southern Persia. It has not yet been established whether the two manuscripts so far traced. but the names of the many physicians who left it to settle in the capital of the new Empire. Persian or Indian. Fihrist. they were good theologians.20. such as poetry and tragedy. pp.O. the Greek philosopher who had sought refuge at his court. whether from Syriac. and who attained considerable wealth and renown. medical and philosophical writings were far more p. as well as a Latin rendering of Chosroes' discussions with Priscianus. as denoting theological speculation. • Cf. and the name Mu'tazila for those who professed 'a state intermediate between two states's may not be quite clear. may be disputed. it should not be supposed that it is always easy to detect them. appreciated and studied than the purely literary. • The Mashhad copy is in the name of himself. And Ibn al-Qifti calls him 'the first person in the Islamic nation to occupy himself with the translation of the Logic books for Abu Ja'far al-Mansur •• . they were neither philosophers.1 then proceeds to specify and enumerate them.s Various sources have testified to the acquaintance of some of the Sasanian kings of Persia and particularly Chosroes I (531-578) with the works of Plato and Aristotlep the Syriac version of the treatise4 which Paulos Persa wrote for him on the logic of the Stagirite. 88. yet the traces seem undeniable. are by him or his son. 16 17 . Agathias: Patrologia Graeca. If these were the routes. The Fihrist attests to the fact that such works were translated into Arabic. Very often there is no direct link between the two. 4Z9 ff. p. Nevertheless their influence proved profound and widespread. Vol. and purporting to be an abstract of some of the books of the Aristotelian Organon.
2. even centuries afterwards. edit. Walzer: The Arahic Translations of Aristotle.' The list of their translations is enumerated in three Arabic source-books. vols. In the Paris manuscript of the Arabic translation of the Organon there are three different renderings of the Sophistics. translations by one person into both Syriac and Arabic of the same or different works. There was first the pre-Hunain school. and meeting every day in their school which bore the Syriac name of Eskol. and they could be more influenced by one of these languages than by the other. And it may be assumed that at least some of the translators were proficient in all four. In the translation of Aristotle's Poetics. his relatives and pupils. and a comparative study of their terms has produced some very interesting results.establishes the fact that they had for aid suitable compilations in the form of instruments de travail. their faithfulness to the original. and comedy ~s understood as invective. a.in another 'the taker of faces. Arabic and Persian.. second. And that in Baghdad the Christians were in the habit of copying that practice. translations from Arabic into Syriac. Syriac. edit. 3 V1TOKXP'TIj. vols.' The literary value of the Arabic versions varies. 2. ever realized that tragedy and comedy are acted on a stage. Ibn Abi Usaibi'a: Tahaqiit al-Atihhii'. The actors was in one rendering translated 'the hypocrite' (al-munafiq).: These presentee a la Sorbonne.> In this we find that there had been cases of: translations from Greek into Syriac. gave equivalents in the four languages more often employed in their work. They also had glossaries I Cf. The same applies to terminology which was of course more important because' of its adoption by their successors. and lamentably sometimes. He further informs us that in Alexandria there were daily meetings at which a specific book of Galen was carefully studied and discussed. Another document. among them were lexicons called by the Persian name of ChaMr Nam which. Greek. They considered them parts of logic and studied them together with rhetoric. • Cf. Al-Nadirn: Al-Fihrist. Arabic or Persian. iiher die syrische und arahischen Galen-ubersetsungen. and third the postHunain school. tragedy was thought to be panegyric poetry. I 18 . Fluegel. edit. and . the school of Hunain. The cultural background of the translators could be Greek. separate translations of the same work by the same person. and their painstaking effort to find suitable equivalents have won the admiration of modem scholars. some translations remaining incomplete due to the absence of the necessary texts.r AVICENNA INTRODUCTION the professional translators.' And A vicenna speaks in despair of 'this thing they call the taking of faces. fall into three groups. The nature of their activities may be deduced from a valuable report by Hunain on the translation of the works of Galen.s. The Arabic style of Hunain was accepted with' some reluctance. viz. revision of previous translations by their authors or by others. Ibn al-Qifti: Tiirilch al-lfukamii'. 1953. Lippert. as the title implies. Bergstrasser: Hunayn ••. Syriac. while that of Quwairi was declared dreadfully complicated and unnecessarily involved.p. R. for special books 'covering strange words and the explanation of the difficult among them. translations from Greek into Arabic. And their careful collation of different copies of the text. C. translations from Syriac into Arabic. But they blundered also. 4 cr. ~ Beriini: Kitiih al-Saidana. an adaptation of the Greek schoU. Haddad. Oriens. Muller. separate translations of the same work by different persons.> In some cases they could be used to correct present-day Greek texts the originals of which reached the West by way of Constantinople. Meyerhof. most of whom were Christians. 1953. with the result that none of the Islamic commentators.of great value. edit. translations by different persons of different parts of the same work. There were those wh? knew no Gre:k at all and translated only from Syriac.
among whom was the highly competent Thabit ibn Qurra. and TO elva. and another close relative and numerous pupils all devoted to the task of translating Greek and Syriac books. the terms of Hunain are invariably employed by those writing in Arabic. he gives the original Greek term. edit. but they succeeded in over21 20 . it was adopted by almost all the Faliisifo who helped to establish it as the technical language of philosophy. and when not using a Qur'anic or classicalterm. they show a decided inclination to benefit from the writings of some celebrated stylist. It is otherwise in the case of medical works. and yet historically his work is worthy of note because his terms sometimes differ from those of the Hunain school which were later adopted by the Falasifo. Though sometimes different from that of his predecessors. In him are united all the four traditions already referred to. and hardly any coining. And today. 873). and preferred to give both terms. It may also be noted that there is a slight difference in style and terminology between books translated directly from Greek and those translated first into Syriac. Very often Syriac is made use of in an Arabized form. and was eventuallyexcommunicated and forced to choose suicide. On the whole. He may well have been the originator of some of the neologisms that shocked Arab purists and delighted the followers of the new school of writing. Averroes: Tafsir rna ha'J al-Tabi'a. We find these in the writings of his friend Kindi. He constantly endeavoured to improve his Arabic. and that it may be doubted whether he himself coined a single new term. and especially with Farabi. The terms annora and huwry-ya. This is why so many of the words found in the Kalila wa Dimna ofIbn al-Muqaffa'. are met with in the translation of Greek philosophical writing.s Arabic sources speak of him as a mediocre translator. which was not particularly strong.AVICENNA INTRODUCTION Among the pre-Hunain group we have the case of Ustath. The Arabs themselves were not interested in linguistic innovations and frequently showed marked disapproval of neologisms. and that of his son and pupils. • Greek rl1}V elva. His son came to write much better and was more appreciated by the Arabs. Of all the translators none attained greater renown and had more works to his credit than Hunain (d. He had the good fortune to have a gifted son who not only shared his interests but surpassed him in ability.boldness. The terminology of Hunain's renderings. Arab sources claim that he was the most proficient of his time in Greek. and even psychology. they are universally accepted. were coined by him. Even among these there is very little linguistic . metaphysics. for the simple reason that the author not knowing Greek could not make the proper choice. associated with the people of Harran. about whom very little is known except that he was a contemporary and associate of Kindi. There he was often obliged to use Syriac and Persian terms for lack of an Arabic equivalent. But he had the ill-fortune to incur the displeasure of his Church. for every Greek expression. Syriac and Persian. Bouyges. His version of a large part of the Metaphysica of Aristotle has survived in a commentary of Averroes. After Kindi.2 we believe. and had a command of these languages that none of the other translators could equal. Among some of the Faliisifo. they still constitute the basis of all books on logic. And lastly come those who give a definiteArabic equivalent of their own. None of the translators was a pure Arab sure of his language and with the courage to coin new expressions. Whenever the translator is in a difficulty and cannot find an Arabic word suitable to the context of the treatise. Among later translatorswe find the transcription side by side with a tentative translation whenever the writer is in doubt. after the lapse I . is very important. who was still attached to the earlier school. early versions abound in transcriptions from Greek. The translation of mathematical works. to of centuries. and curiously enough in the history ofYa'qiihi. we find two alternative renderings of the same Greek term used together as synonyms. respectively. needed a different terminology. or a term borrowed from some literary author. In spite of the fact that there is very little originality in them.
and in true NeoPlatonic fashion he felt he could combine Plato with Aristotle.AVICENNA r * * INTRODUCTION coming this difficulty. and were notably successful in their choice of terms. and is the author of a treatise still extant On the Number of the Works of Aristotle and those Necessary to the Study of Philosophy» There is no reason to believe that. Dieterici. His theory of the intellect has been traced back to Alexander of Aphrodisias. Kindl translated Greek works into Arabic. S Edit. but we have a short essay on the intellect (' aql) which was translated into mediaeval I 3 Edit. Persian and Indian arts of wisdom. Two books proved to be most confusing elements in Islamic philosophy. 'He was famous in the Islamic nation for his profound knowledge of the Greek. I. he is the first of the Faliisifo to be deeply influenced I Fihrist.D. Qifti. • Ex. and Kindi was associated with one of them. I.. A. From the list of his works it may be inferred that he was most interested in the natural sciences though he also left treatises on Logic and Metaphysics. Fihrist. He may have been the first in Islam to be inspired by the personality of Socrates on whose exemplary life he is supposed to have written some treatises. a Persian.) where his father was governor. The first was a work that became known as the Theology of Aristotle+ though it was actually parts of the Enneads of Plotinus (Books IV-VI). This was translated by Ibn Na'ima. as has often been asserted. pp. to philosophers of history as Ibn Khaldtin. 206 ff. 362 ff.5 actually comprising parts of the Elementatio Theologica of ProcIus.. laisa. regrettably little has survived. The Faliisifo stand in sharp contrast to religious thinkers such as Ghazali and Ibn Taimiya. 255 ff. Cairo. a Turk. Like Plato he was devoted to mathematics and wrote a book entitled In that Philosophy cannot be Attained except by way of Mathematics. * * The field of Islamic philosophy is dominated by three figures: Kindi. p. Whether that can be taken as a fact or not. With occasional doubts. and a member of the Mu'tazelites. 1953· 3 Qifti. Vol. I. it was throughout believed that they were both by the Stagirite. pp. pp. Vol. Usaibi'a. by the Stagirite. Some early Arabic sources have stressed that Kindi was the first to introduce Aristotelian thought into the Islamic system.ts He became known as 'the philosopher of the Arabs.s A man of means associating with Caliphs and Amirs. Abii Raida. he was in cIose touch with the early translators and may well have supported some of them. Farabi. 23 22 . Admittedly his terminology differs sometimes from that of the Faliisifo who followed him. But there is also Platonic thought in Kindi. Vol. His cosmology owes a great deal to the Timaeus and his theory of the soul is derived from the Phaedo-a book deeply appreciated by Islamic thinkers. laisiyya. educated in Basra and Baghdad. Vol.: 'aisa. and he was an expert astronomer. The new terms.whereas his successors used the versions of Hunain and his school. a pure Arab of princely lineage. 260. 366 ff. and Avicenna. there is no doubt that in the field of secular thought as distinct from religious speculation. 2. 1950. 367.3 His mathematical writings are based 'on the Neo-Pythagorean principles which he considered the fundamentals of all the sciences. The other work was what the Occident called Liber de Causis. pp. but that is only because he was using the versions of Ustath to whom reference has already been made. an Arab. • Rasjj'u al-Kindt al-Falsafiya. The source-books! quote over two hundred titles but what remains fills two small volumes. . Abii Raida. edit. and in this manner Neo-Platonic thought was unknowingly introduced into Islamic philosophy. Of the works of Kindi. as will be seen. born in Kufa (middle of the ninth century A.' but it is not certain that he had many pupils or formed a school of his own. p. aisiyya. Kindi's treatises on logic have been lost.thought to have been coined by him are actually those chosen by Ustath. Bardenhewer. and to those who were primarily commentators like Averroes and his Andalusian school.' 4 Edit. and Kindi probably helped him in polishing up the Arabic. I.
I.. for the true prophets. One distinguished authors has claimed that it comes from the De Anima of Alexander of Aphrodisias. .. 'We maintain in this our book our custom . and creation is only a form of Movement. 101. Paris.' and again in an early Latin translation 'Tempus ergo est numerus numerans motum. a Scholastic'demonstrativum.. then the world cannot be I Rasa'iI. a Ibid. 3 Rasa'il. The 'apparent intellect' (al-'aql al-~iilzir) of Kindi is a typical example. Gilson: Les Sources greco-arabes de l'Augustinisme avicennisane.x If Time and Movement are not infinite. I. came only to confess the divinity of God. and he who sells something loses it . 103. 24 .. they have fallen into serious errors. How to reconcile these two conflicting views expressed in the terms qadim (old. I. He pays tribute to 'philosophers before us not of our tongue. Vol. he argues at length to show that Time and Movement are not eternal and infinite for 'Time is the period of the existence of a thing so long as it exists. 3 IOid. second comes the intellect that is in potentia..says is apparent (iiilzir)1. pp. avoiding the interpretations of those .•• man's existence is twofold ••• a sensual and an intellectual existence/a With· these introductory remarks. third is the intellect that has passed in the soul from a potential to an active state. p.9.•• to the extent to which we are capable . 353. Kindi enters into the discussion. . 35. 192.' Cf. They were particularly well acquainted with the works of Themistius of which Arabic translations have recently begun to be found and studied.•. Archives d' Histoire doctrinale et lltteraire du Moyen Age. and addressed to one of the 'Ahbasid Caliphs-is important because it deals with one of the main themes of Islamic philosophy. What could the original Greek be? Vol. eternal) and mubdath (created)? Metaphysics he calls 'the highest in honour and rank . 2.• to recall what the ancients have said . but there the division is threefold only..in the soul once it has appeared m the actrve state. In this he proceeds to dISCUSS intellect and its varieties according to what the he supposes to have been the opinion of the early Greeks and also of Plato and Aristotle 'the most esteemed of them. from wherever it may come. • . And towards the end of his essay he speaks of the fourth kind ~hich he.AVICENNA r I INTRODUCTION Latin und~r the title ~f De [ntellectu et Intellecto. Vol. p. whereas the Mutakallemiin (Loquentes) vehemently protested that it was created ex nihilo by an act of the Almighty. for he who trades in something sells it. 4 uu. because the science dealing with the cause is more honourable than the science dealing with the caused. Vol. Vol. 103-4. and to amplify what they have not discussed conclusively . and the necessity of those virtues pleasing unto Him . The fourfold division of the intellect is not to be found in the De Anima of Aristotle and scholars have searched in vain for its source. and when scholars have taken it upon themselves to infer the original Greek of some Arabic philosophical term without reference to the actual translation on which the Faliisifo worked. I Kindi's treatise on Metaphysics-the longest of his extant writings. who trade in religion and have none of it themselves." He then goes on to state that in the view of Aristotle intellect may be divided into four kinds. T?ere is first the intellect that is always in actu. . p. Another difficulty is that whenever an attempt is made to put a particular passage from Arabic into some European language it is found that it often defies translation altogether. Contrary to the views of Aristotle. This short treatise exemplifies problems typical of many passages of Islamic philosophical writing.. p.•. Aristotle had said that the world was eternal. even if it be from distant races and people different from US. IV. upon whom may God's benediction rest.'2This marks the dawn of the true scientific spirit in Islamic philosophy and is perhaps its first enunciation." and this is typical of the attitude of all the Faliisifo. Vol. We should not be timid in praising truth and in seeking it.. I. The fact is that Islamic philosophers made much use of Peripatetic and Stoic commentaries on Plato and Aristotle and very often what they thought was genuine Platonic or Aristotelian thought was actually the interpretation or the personal opinion of some commentator.
for whom philosophy had two sides. with no fundamental opposition between the two. I. He eclipsed Kindi and except for Avicenna. it is only due to our faulty understanding. 1944. Kindi was known to the Mediaeval Latins. . It goes back to God who is the Primal Cause. edit. Farahi was in many ways different from Kindi and has more in common with his successor. 263. because that would be absurd. In thought Farabi is not lacking in originality. There is nothing in the world with which philosophy is not concerned. I. if the world is finite it had a beginning. and he shows a strong interest in political science. Modest and of a retiring nature. 277. His was a very suggestive restatement of the speculative thought of his day. he wrote only in Arabic and left a valuable heritage for all Islamic thinkers after him. znd edit. stands foremost among the Falasifo. By contrast with Plato. one religious and the other secular. pp. Yet there is nothing new or peculiar in his terminology. AMana. There was also. it must have a Creator. it is also theocentric in contrast to the anthropocent~i~ conceptions of the Athenian thinkers. if it was created.. 248. though there are already traces of Stoic logic. of Logic and its branches. with all the different influences that were shaping it. Fihrist.than of Kindi. a Cf. he was born in Transoxiana. he thought. AlfaraIJi's Philos. Paris. 41. Dieterici. the mystics. Ibn al-Qifp3 calls him 'the unrivalled philosopher of the Muslims' while Ibn Taimiya calls him 'the greatest of the Falasifo in the exposition I Cf. Educated in Baghdad. pp. It must have had a beginning and might have an end. 3 P. p. protige of the Hamdanite dynasty in Aleppo. Its beginning was in the hand of God. All caused things must have a cause and the chain of causation cannot go back indefinitely. 375 fr. He did not share Kindi's particular admiration for Socrates nor was he very much inclined towards mathematics and the natural sciences. though more of his works have survived and his influence was much greater. considered him one of the twelve subtlest rninds. His is a more comprehensive attempt to reconcile religion with philosophy. he wrote a whole treatise to prove the complete agreement and unity of thought between 'Plato the godly.. pp. also Brockelmann: G. Gilson: La Philosophie au Moyen Age. His intellectual background is wholly Islamic. 264. 339/95C>-CJ5I) we enter into the field of Islamic philosophy proper. if it had a beginning it was created. Vol. Vol. apart from his spiritual mission. he was intellectually bold and tireless. He considers the personality of a prophet as a social and intellectual leader. 210 fr.A.'> The Neo-Platonists before him ~ad done the same. If Islamic philosophy is by nature synthetic when compared to the analytical method employed by the Greeks of the classical age. As his language includes terms associated with the theologians. Thus in this difficult problem he takes the religious view in opposition to Aristotle. and Aristotle. And again in proof of God. but unfortunately very little of his work on that subject has survived.s With Abu Nasr al-Farabi (d. Called 'the second teacher' (Aristotle being the first). which were to become more marked in Avicenna. he claimed. an agreement on essentials. the method . To demonstrate that principle. Supp.L. Gerhard of Cremona was among his translators and Cardan. but he is far better informed than Kindi about Greek philosophy in both its classical and its Hellenistic form. ~ Cf. a Renaissance philosopher. grandson of a pagan Turk. J AI-Radd 'ala al-Mantiqiyin. and where there is an apparent divergence.. we may presume that he was familiar with their literature. Both trends are distinctly reflected in the systematic speculations of Farahi.. He did not belong to the same social class and although he had come in his early youth to Baghdad he was always known as a Turk. 26 27 . who was greatly indebted to him. He created it ex nihilo by His own divine Will and will end it when He wills. and the Isma'ili heterodoxy. Not much more is known of him. it is that established by the Hunain school and there is no evidence that he knew any Greek.AVICENNA INTRODUCTION eternal either.'! Andalusian commentators also regarded him as a great logician.
second is the intellect the theologians speak of. clarification and exposition. and among those whom he mentions are Ammonius. Farabi confidently asserts that it is not true that only some parts of it are by Aristotle. Badawi: Aristu 'ind al-'Ara6.'Aql. all conducted with remarkable insight into the nature of things. Farabi thought.to the various meanings of the term Intellect. Like Kindi. as has been said. in spite of its obvious disagreement with other writings of the Stagirite. third is the intellect that Aristotle discusses in the Analytica Priora.' He was thus asserting that a creation must have an original creator. and fourth is the intellect he expounds in the sixth book of the Ethics. But his chief source is always the Theology. Movement and the world was indeed a stumbling-block. It should not be supposed that this list is meant as a strict classification by Farabi. he thinks. especially on the immortality of the soul. he remarks that 'the intellect which Aristotle mentions in the book on the soul [De Anima]. 28 . On the vexing question of the eternity of the world. he makes of tour modes. helped us to understand Aristotle better. nor can it transmigrate by metempsychosis which is a conception abhorrent to the Islamic mind. will not fail to understand his position. whilst others are not. Some had had doubts with regard to the authenticity of this work. as the theologians insisted. According to him. but Aristotle was in general preferred. and an active intellect. however. His logic and his metaphysics supplied a great want. God as the efficient cause was the originator of all things. without properly specifying the sense intended. he tries to show that Aristotle never really meant that the world was eternal. It is often used. yet--contrary to Plato-it could not have existed before it. In accordance with the views of Aristotle. but Aristotle soon became the chief guide and continued so ever after. though attempts were made to explain it away by some of the passages of the Theology. Bouyges. Plato. 29 edit. as well as from Book Lambda of Aristotle's Metaphysica. and his natural philosophy was a source of information unobtainable elsewhere. The Repuhlic was studied. UI. I on the other hand. Curiously enough when he reaches the fifth sense of the term. p. distinct from the soul which is an entity entirely separate from the body. classification. Fifth is the intellect he analyses in the De Anima. however. He is the One and the True. however.' So here we meet again the fourfold division found in . an acquired intellect. adding-and here comes the source of confusion already referred to-'he who looks into his statements on the Deity in the book known as the Theology. First there is the intellect the common man has in mind when he says somebody is intelligent. and he explains each in some detail.AVICENNA INTRODUCTION which Aristotle chose involved observation. The commentators. it is rather a set of illustrations of the different meanings that can be given to the word intellect. what he regards as proofs for the existence of God as the first cause. The contribution of Platonism to Islamic thought was certainly not inconsiderable. Farabi devotes a whole treatise. held some very attractive and congenial views. It is the human soul that is endowed with the reasonable faculty and it is this that is responI cr. another in actu. The nature of his writings and their subject-matter helped to give him that paramount influence. was among the doubters. and much was borrowed from it. Nevertheless he seemed to the Islamic thinkers to be occupied with aspects of human life which properly belonged to the domain of religion. Kindi and the problem of how it entered Arabic philosophy.' though he nevertheless continued to make full use of it. though it still awaits careful assessment. Risalat ft al. Avicenna. and his proof for an original creator of this world. For them it was God and not man who is the measure of all things. Intellect could have six possible meanings. an intellect in potentia. His doctrine of the eternal nature of Time. he teaches that the soul has parts and faculties through which it acts and that these parts and faculties form a single soul. and sixth is the intellect he mentions in his Metaphysica. Intellect is. Farabi proceeds to quote from Plato's Timaeus and Politeia. Themistius and Porphyry.
And the spheres that come into being from them are: the first sphere. intelligences and intelligibles in their substance. It is he who gives them existence. In expounding his metaphysics. He cannot be defined. Et. because he is not divisible into elements constituting his substance. Thus Farabi develops his theory of emanation clearly along Neo-Platonic lines. As will be seen. From the first being there emanate successively ten different intellects or intelligences. the sphere of Venus. the sphere of Mercury. And as such he is the first from whom being proceeds. First is the division of all beings into two kinds. Hence intellect is one of the faculties of the rational soul. The other kind when it reflects upon and considers its own self. Farabi raises two points which were to be developed by A vicenna who made it the basis of his own thought and connected it with his proof of the existence of God. so it is called a necessary being. Dieterici • in substancefrom all others besides himself. . there is plenty of Aristotelian and Plotinian thought intermixed. and modelled on the Repuhlic of Plato. One kind. the sphere of Jupiter. He transcends all and everything. His oneness is his actual essence. and it is not until we reach A vicenna that they become metaphysical essentials and play the role of an ontological distinction of great significance. From the being that is his due other beings proceed necessarily. We thus have God as the First Being. The intelligences are absolutely incorporeal substances and in no way reside in matter. though differing in some details. 3 Edit. and the true and the living and the life. finds that its being is duly necessitated. Only in God do they become identical. But how and in what manner do other beings proceed from him? Here Farabi maintains that it is by way of emanation (fait!) from God's own essence that all existent things come to be. and does not reside in matter. This division is found in a treatise. His existence is not governed by the will of man nor by his choice. nevertheless it is not wholly Platonic in substance. it is in fact impossible that he should have one. They are separate beings. The first being is the first cause. the sphere of Saturn.> Second is the distinction among created things between their essence and their existence which differ from one another as different entities. Nor is the influence of the commentators entirely absent. From him emanate the ten intelligences with their nine spheres as a second species of being which represent 31 30 . 1951. This' comprises all the beings that in order to exist in this fashion have no need whatever of matter in which to reside. Cf Pines: Rev. The most representative work of Farabi that we now have is his Ideas of the [nhabitasus of the Fatuous Ciry. and the sphere of the Moon. the sphere of Mars. He is not corporeal. and from each of these when 'substantially constituted in its proper essence. upon contemplation of itself. should be over-emphasized in Farabi's system. the sphere of the Sun.so similar in style and context to the writings of Avicenna that he may well be its author: just as another work commonly attributed to Farabi has been proved to be by his successor. governed by the principle of complete unity. None of these two points.whom he calls the necessary being. Islam. They do not constitute a fundamental element in his speculations. He is the knowing and the wise. From the Moon there proceeds a pure intelligence called 'the active intelligence' which bridges the gap between heaven and earth. Farabi begins by enunciating a form of theodicy rather than advancing proofs for the existence of God.3 It is one of the very few books in Islamic philosophy to be directly inspired by .' there results a sphere. In essence he is an intelligence in aetu. finds that its existence does not follow necessarily. • FUfiis al-lfilcam.AVICENNA INTRODUCTION sible for our acts of cerebration. and the creator of all other beings. however. He has no opposite. so it is called a possible being. as has sometimes been done. He is different I 'Uyi1n al-Masilil. And the sphere of the Moon is the last of those in which heavenly bodies move by nature in a circle. the sphere of the fixed stars. a species by himself. And the process is not direct but takes place through successive stages until it reaches this sublunary world of ours.
') is to our kno~l~dge not found anywhere in Islamic literature before him. which were numerous. of his philosophical works. though strongly inclined towards -mysticism and himself an ascetic. Then comes the active intelligence as a third. Society. or are led to confine themselves in their theoretical knowledge. Unfortunately his commentary ?n the Nicomachean Ethics has been lost and we have no clear Idea of his views on morals and human conduct. There have been many modem attempts' to trace the origin of this theory of the ten intelligences to Christianity. edit. can we with certainty determine in how far his ideas were original. Farahi's classification of the sciences3 was translated into Latin La Place d'al-Farahi. singer and musician in his early youth. Sabeism. Baron d'Erlanger: Grand Traite de la Musique.' What is not clear is whether he founded a school of his own. And yet in spite of many modern attempts.' The terms philosopher. known to the Europeans as Rhazes. and fearless in the expression of his views. lawgiver and Imam all mean the same because they represent different functions of the same individual. and what remains are fragments. The whole idea is novel. and an eminent theologian of much later times confidently asserts that he was 'the leader of the philosophers. so modem in its application. 91. and what particular aspect of his thought had most appeal for the men of his time. and the function of an initiator of public opinion (hadi aI-ra'yal-mushtarak). Razi. and stayed Iong enough to become the head of a hospital there. constitutes an entirely new conception in Islamic political thought an~ State administration.r . it seems difficult to arrive at a proper general estimation of his contributions to Islamic philosophy. are described along the lines of those required for Plato's philosopherking. N~ir Khosrow: Zad el-Musaferin. Finally. Isma'ili doctrines and various others. I and widely used in mediaeval Europe. Manichaeism. This IS an interesting point that has not been noted so far.5 or 935). He then returned to his native country where he won both fame and notoriety before he died blind from cataract. first head. Mazdaism. have survived complete. His treatise on music' has been called the most important Oriental work on the theory of that art. was composed of the common class and the nite. The common class are those who confine themselves. Farabi. and blamed him for parting company from his master. as a counterpart to consensus omnium (ijma. 3 liMa' al-'uliim. • Abu Bakr Muhammad ibn Zakaria a1-Razi (d.3 It is therefore difficult to form a proper estimate and say with certainty whether he developed a coherent system of his own. a poet. Madkour: B 33 . but no conclusive proofs have . some gleaned from the books of his detractors.' was also an independent thinker bent on speculation. to what the initiator of public opinion requires. while the public is to be taught 'by methods of persuasion and imagination. In these he was much influenced by the Repuhlic and perhaps by some Isma'ili doctrines. and various scholars have traced his influence upon Scholasticism. but he elaborates at length a theory of prophetism. and politics and State organization. in the last stage come Soul Form and Matter. Very few.1. He should be well versed in the science of the intel!igibles. whom he calls the Imam. also touched upon two subjects that reveal a more practical tum of mind. and for 'corrupting philosophy I cr. Amin. This division. AVICENNA INTRODUCTION plurality. He expressed strong disapproval of the latter. a TalJiil al-Sa'ada. and none of these species are corporeal themselves. Not until the Arabic translations of different Peripatetic and Stoic commentaries are traced and studied. king. he left Persia to study medicine in Baghdad. Born in Raiy (Rhages). cr. One of Farabi's contemporaries chose to take a different path. 3 cr. emerged. His position in the Islamic world was undisputed for centuries after him.and considered 'the greatest clinical genius amongst the physicians of the Islamic world. He took the then unusual step of championing the cause of Plato against Aristotle. The qualifications of the head of the Virtuous City. he thought.
Razi himself claimed that it came from some early pre-Aristotelians. 3 IhiJ. and that any man who is sufficiently endowed with intelligence can use it to fashion his own life and achieve his own salvation. and Ibn Taimiya has stated that he acquired it from Democritus. Some Arab authors thought that the notion originated with the Harranians.3 1 There exists an impressive list of the works of Razi. The idea. Yet he was no atheist. and his non-medical works have almost entirely disappeared> Early i~ the tenth century. of whom practically nothing is known. Arberry.' Space. Beriini: Risiilat ••• . Qazvini: Aha Sulaiman Mantiqi SiJjistiini. there was another philosopher of Persian extraction in Baghdad by the name of Sajistani. providing yet another reason for condemning him. Nor were Razi's political and religious views any more orthodox. Nevertheless his theism was not considered sufficient. and he must have deeply shocked Muslim society by his assertion that there is no necessity for prophets whatsoever. his life and teachings. edit.. however. edit. Matter. calling him 'our Imam. Space. was 'nothing but a return to the normal state. and that there was no reason why he should be one." And like Kindi he had a deep admiration for Socrates. independent of the revolutions of the celestial sphere and co-existent with eternity. Kraus. • Cf. 'the bestower of intelligence'. his philosophy evoked horror. 25%-4. pp. His Platonic thought stemmed mostly from the Timaeus on which he had written a commentary. Opera Philosophica. Nor had he any scruples about rejecting the metaphysics of the Falasifa with its elaborate conception of successive cycles of emanation. and that is not easy to reconcile with the principles he declared. In this he seems to have gone contrary to the views of one of his teachers by the name of Iranshahri. The Spiritual Physiclc of Rhates. but his home became the chief literary and intellectual meeting-place of his time. was his outspoken denial of the possibility of reconciling religion and philosophy-a theme they not only consistently maintained. and on the other hand limited Time (taman maMiir). ed.3 Because of a physical deformity he rarely appeared in public. he had said. and his definition of pleasure. 3 Cf. The second and more important point on which Razi dissented from the views of Kindi and Farabl. %4I. however. p. and we must believe his repeated invocations of the Deity. J. Acquainted with the Greek Atomists. developed under Neo-Platonic influence. Sachau. on which he is supposed to have written a book. A16irum's India. Hence it is hardly surprising that although they called him the Galen of the Islamic world and studied his medical works assiduously. Kraus. was infinite. He was denounced as a heretic and never gained a following. 3 Cf. God.' as some have called him. was a very different form of atomism from that which had been adopted by the Muslim theologians. Socrates had even gone to fight for his country. and is supposed to have written many commentaries on Aristotelian logic and kindred subjects+ Princes as far distant as the Samanids of Transoxiana addressed 1 Cf. is typical of Razi's unorthodox views.' When people accused him of leading a worldly life himself. and a partial (jU{'iy) space. trans. according to him. While they maintained that matter (hayiila) had only a potential existence. He was called the Logician. Razi was much influenced by Democritus. Soul. The source of his theo~ IS not clear.> Pleasure. 4 Fihrist. 34 35 .I but perhaps his most interesting theme. and Time. he answered back that Socrates had been no ascetic. and it surprised and annoyed Islamic philosophers and theologians alike. A. but one which constituted the whole purpose of their thought. In like manner there is on the one hand absolute Time. His. nor was he 'the Voltaire of Islam. was what he called the five eternal substances ~iz. I43. p. For some obscure reason he became the object of violent condemnation by Isma'ili authors who bitterly attacked his theories of Time and Space. but there is an absolute (mu!laq) space which is the void.AVICENNA INTRODUCTION and changing many of its principles. he saw no reason why it should not also have an actual existence of its own.
and observed. II. Most of what we know about him is found in the writings of his pupil and friend Tawhidi. Gnostic and even Indian ideas. . 10. 4 Rasitil Ilchwiin al-Safii. and where philosophy? Where is that which proceeds from revelation. ZirgaIi. Vol. 45-51. and the other says "I have the light of the Creator of creatures. and do not say anything from my own self" . IT. p.'z This collection of essays has failed to impress students of Islamic thought.' Practically all of his works have perished. Vol. by its illumination I walk .. p. What they had imagined they could accomplish was to introduce philosophy into religion." '3 These statements appear in an account of a discussion between Tawhidi and his master over a collection of some fifty-two semireligious. and from these accounts it appears that on the crucial point of the relation between religion and philosophy. Sajistani took a position midway between the sanguine confidence of the Falasifo that a reconciliation or synthesis is possible. and he who chooses religion must avoid all attention to philosophy . • • • One says "I was ordained. 18-19.l AVICENNA INTRODUCTION philosophical questions to him 'by the hundred. and Sajistani after perusal turns to explain to his pupil that the attempt is in . presumably for free distribution. and where that 'which is based on an opinion that may change . Sajistani may be considered the most distinguished thinker between Farabi and Avicenna. • Muqiihasiit. Nor could religion be attached to philosophy. ed. 'but it is in no way a part of religion.. and constituted • Cf. semi-philosophical essays by a group of anonymous writers that had become the talk of Baghdad. 534-8. pp. seeing that each had its separate domain and they could never merge. But it should be remembered that originality was not the purpose or claim of the group. perfection would be attained. and very few have taken a favourable view of it. 'Philosophy is true.• He who wishes to philosophize must tum his gaze away from religion. an invitation to join what was perhaps a secret fraternity of 'seekers after truth' uncommitted to any particular faith or philosophy.4 It had been placed quietly in the bookshops. Islamic. 36 37 . keenly interested in everything. nor join any special group. and religion is true. They regarded themselves as completely independent. They attached great importance to the principle that if Greek philosophy was properly introduced into religion. and the philosopher is delegated unto him. ? The prophet is above the philosopher . a Baihaqi: Tatimmat Siwan af-l. and free to examine all that might be said or written. 3 Cf.•. I When questioned by one of the prominent citizens of Baghdad as to the religious faith of that member of the fraternity whom he happened to know. and the other says "I saw. If we exclude Razi as primarily a physician.•• One is concerned primarily with inspiration and the other with the search for truth. Persian.lilcma." One says"the light of intelligence is what I seek guidance from" . others had tried before them and all had failed. Tawl)idi: Imtii' ••• . that they did not officially attach themselves to any particular religion. We know that he was the author of a compilation of biographical notes! on Greek philosophers.. Tawhidi was among the very few who knew some of the authors personally. and disapproving rejected. In the account of this discussion Tawhidi takes a copy of the epistles to his master.. and extracts from this have survived in a later work that provides some useful information> . and neither one destroys the other. Philosophy was based on logical reasoning and religion on premisses that the intelligence 'sometimes demands and sometimes allows. The authors were supposed to have come from Basra. pp. IV.' He expatiates on the distinctions between the two disciplines and ends by saying: 'Where is religion. and taught.• for the prophet is delegated.3 It is undoubtedly an extraordinary mixture of Greek. vain. a Imtii'. he replied that it was typical of that person (and apparently of his companions). but it is in no way a part of philosophy . and the outright repudiation of any such possibility by Razi.' he says. Plessner: Beitrage ••• Islamica. and told.•. 'Awwa: L'Esprit critique des Freres de fa Purete. and the book was entitled Epistles of the Brethren of Purity. and approving accepted.
They were of Arab extraction. active in the Ba~h~ad of the 'Abbasid Age.H. The first to establish their authority. and when literature and learning deserted Damascus to flourish as never before in Baghdad. Modern Arabs while objecting to almost all that they assert have nevertheless appreciated their simple style.AVICENNA They were avowedly eclectic. however. When the Umayyad Caliphate was succeeded by the 'Abbasid. in time if not in sentiment. and theY'put forward allegorical interpretations of some of the passages In the Qur'an which must have deeply disturbed the orthodox. were gradually recovering and the time seemed auspicious.b al-Jami'a. 38 CHAPTER I PERSIA IN THE TENTH CENTURY age of Avicenna differed from that of Kindi and Farabi. from 809 to 873 (194-259 A. and the original impulse may have come from the personal ambition of local commanders who found it expedient to exploit the sense of frustration of a people who. ~vicenna. which culminates in the person of Avicenna. always been rightly associated with the Isma'ili heterodoxy.tes. Kindi and Farabi were the products of the golden era of Arabic. then.). supposed to be only fo: the initiared. his father and his brother are supposed to have studied them either in the original or in a Persian translation. The Persians. problem re~ains perennial and has to be met in every age. but in time had become thoroughly THE 39 . But tenth-century Persia was to witness a change in the political scene and the re-emergence of prose and poetry in its own tongue. to an historical period and a national phenomenon known as the Persian Renaissance.ISa ~arren and disappointing work devoid of particular interest. which methods upset Baghdad literary circles and caused much speculation as to the authorship of the essays. and the weakening of central control was encouraging the rise of local dynasties in regions that had indeed never been very submissive. It is to A vicenna. philosophies and ways of thought. they were developed in the language of the conquerors and of the new Faith. It . and A vicenna belonged. Nevertheless the fundamental problems of Islamic philosophy persisted-the needs and purposes having remained the same. The gr~U?:s recently found Kita. ' The pu~ose of this brief historical survey was to indicate the forces which were. Decline had set in over the 'Abbasid Caliphate. Hlstoncally. and it is among its adherents that they were most popular. had never forgotten their ancient heroic history. the essays are important. The awakening of the new spirit was not at first widespread and sustained. who had suffered a stunning defeat at the hand of the Arab conquerors. Their failures and successes are part of the history of ideas. d' etre and the justification of Islamic phi!osophy. but the. It IS difficult to say how much politics was involved in these tracta. that our attention must now be directed. were the Tahirids in Khurasan who reigned some sixty-five years. however. h~s unf~r~nately added little to our knowledge. this meant a continuation of Arab rule. Its Importance IS compelling for a civilization on the march and it ~onstitutes the raison. though devoutly Muslims. free from artificiality ornamentation or obscurity. because they refl~t far better than the writings of the Falasifo the religious ~nd intellectual ferment that was working in Baghdad under the ~mp~ct of various religions. seeking a synthesis of some sort. They have. ~er~ ~e conq~enng power of religion meets the restraining discipline of rational analysis and explanation and active minds are i~m~diately engaged in attempts at reconciliation or synthesis. but s~me scholars have undoubtedly gone too far in accusing the writers of deliberately subversive aims. preserving only a nominal allegiance to the Caliph. They presented their ideas in an encyclopaedic order under the various headings and in a langUage easy for the common man to understand.
Now his grandson. It had nevertheless succeeded 10 ~evivingthe national feeling that had languished for so long. This dynasty reigned for a period o~ ove~ a hundred years and its members were distinguished by a liberality that made them famous throughout CentralAsia. edit. Niildeke Festschrift. which is the period 10 which AV1cenna was born. there were besides the Samanid rulers thr~e other local dynasties in and on the eastern borders of ~e~s1a proper which were to determine many of the events of his life. but on his return he had resumed his independent attitude. Ya'qiib marched triumphantly from one province to another.).. and he began openly to defy the Caliph. and made Bukhara their capital. a man of 'unknown antecedents. But his camp was I Browne: A Literary History of Persia.s Attacked from two directions. During this period there was a revolt against the Caliph in Tabaristan. an~ so t~e1r ancestor may well have been the warden of that frontier regton between Persia and Chinese Turkistan which produced some of the most celebrated poets. At the head of an army he marched towards Baghdad with the intention of deposing him and installing another Caliph in his place. Mazyar. flooded with the waters of the Tigris. Late in the tenth century. known to his people as al-Saffar (the Coppersmith).s From Sisran. and with two other provinces annexed. the Tahirids. Some of them were men of accomplishment and hterary. who rose rapidly to power in Transoxiana.' . and betrayed by his supporters. 'It is a matter of common observation that settlers in a country. In the region around the Caspian. I. carried to Baghdad. and had helped to detach permanently the history of Persia from that of the 'Abbasids of Baghdad. Zam al-Akhhiir. closely connected with the court of the Samanids. It was soon able to defeat the Saffarids and to extend the frontiers of its rule from the Jaxartes almost to Baghdad. thereby becoming master of a vast realm. was raising the standard of revolt both against the Caliph and against his personal enemies. and in the year 873 took captive the last of the Tahirids. p . The name of the father of the dynasty is usually interpreted as 'the lord of ~e village of Saman. trans. The first Qarinid had successfullyraised a combined army of local chiefs against the army of the Caliphs.~ The dyna~ty was founded by a certain Saman Khudat. unrepentant. and had then been defeated and carried to Baghdad." From their capital at Nishapur. Nazim. 85-107. His conquests gave him confidence. the dynas~y ractically ceased to exist. . where he died. outdo those native to the soil in patriotic feeling. 4 Cf. This region which. 40 n* .the conquest of Persia and the extinction of the Sasanians. the Blacksmith. Narshakhi: History of Bukhiira. is 'the Mountain Land' along the south coast of the Caspian.T ! AVICENNA PERSIA IN THE TENTH CENTURY Persianized. When his brother and successor was finally defeated by the Samanids in 900. including Avicenna himself.'3 founded a dynasty which. however. Barthold: Zur Geschichte der Saffariden.' but siimOn also means frontier. Marin. he was captured. 3 Cf. The last Persian rulers there were the Qarinids who claimed descent from the national hero. pp. his place of origin. a considerable part of his army perished helplessly. the Ziyarids had seized power 10 928 and established a local dynasty that endured for more ~han a century. extended its rule over the greater part of Persia and almost as far as Baghdad. and from the Caspian to the borders of India.. and died in Samarra in 839 (224 A. in 879. and he had to retre~t to Gundishapiir. . Vol. This explains why some have called them 'the Wardens of the Marches. Tabari: The Reign of al-Mu'tQfim. The Persian Renaissance. 346. their rule extended eastward as far as the frontiers of India. though short-lived. was under Zoroastrian ispahbuds long after. including the rather restl~ss Tabaristan which had been one of the last strongholds of ~ers1an ~ationalis~ and culture. theologians and philosophers.H. often after comparatively brief residence. It was left to a humble coppersmith to revive the true spirit of independence among the Persians. as the name implies. a Persian Zoroastrian onverted to Islam by the Arab governor. I Cf. was more. • Cf. Ya'qiib the son of Laith.
until. far towards the East. particularly in the direction of Persia and T ransoxiana. and they had always maintained some freedom of thought. To this noble gesture he sometimes added force. It was for that reason that there had been numerous semi-social. the great patron of scholars and poets who helped the progress of the Persian Renaissance. 43 . The period of the Translators had come to an end long before. and a modem author has called him. and generously spending some four hundred thousand dinars every year upon them. 'the kidnapper of literary men. The history of the Persian language and the different stages through which it has passed has yet to be written. These grew far more powerful. In Baghdad intellectual activity seems eventually to have come to a complete standstill. G. Under 'Ala 'el-Dowleh theology and jurisprudence were more in favour.> The rise of this dynasty of Turkish origin may be seen as part of the struggle that lasted many years between the Iranian and Turkish races for the mastery of that important border-land already referred to. and proclaimed himself Sultan. but the enthusiasm for the new learning-for such indeed was Greek science and philosophy-was waning. and who also reigned for over a hundred years. and the Mu'tazelites were persecuted at the urgent instigation of the Caliphs. Bailey: Zoroastrian Problems •••• 42. absorbing the Ziyarids and overthrowing the S~anids. not without justification. As to literature. and eventually took Baghdad itself in 945. The Ghaznavid dynasty which appeared on the eastern borders of Persia and eventually succeeded in pushing back the Buyids. • Cf. One of the important effects of this dynasty upon literature was that it carried the use of the Persian language. Browne. who conquered practically the whole of Persia.AVICENNA PERSIA IN THE TENTH CENTURY taste who played a notable part in the promotion of Ieaming. And it was Mahrmid. And the accounts of its revival in its postIslamic form are fragmentary and obscure.' His powerful dynasty reigned ruthlessly for about a hundred and fifty years I Cf. was of very humble origin. rendered a great service to Persian literature by gathering around him at his court most of the famous poets and scholars of the time. Baghdad continued to be the centre of Islamic culture in the tenth century. The dynasty reached the height of its power under 'Ala' el-Dowleh. with even a tendency to be critical of all that was of foreign origin. Yet Sultan Mahmild. rapid decay set in. semi-religious movements during the first three centuries after the conquest by the Arabs of that countryI-a sign of continuous unrest. and the general attitude of mind had become more sober and reserved. and some parts of India. the Persians were using the Arabic language for all forms of literary composition-perhaps to the total exclusion of Persian.« but in the form of religious tractates. There were some Pahlawi writings that continued down to the ninth century. N~im: The Life and Times of Sultan Mahmua of Gharna. either out of vanity or from genuine appreciation of the arts. E. and what remained was shifting eastward. Sadighi: Les Movements re/igieux iraniens•••• • Cf. It was founded by one of the Turkish slaves of the Samanids who had fled from Khurasan to Ghazna and established himself there in defiance of his old masters. I Cf. conquered and controlled the whole of western Persia. as with all the others. It is not clear how and when it accepted defeat and left the literary field almost entirely to Arabic. though along somewhat different lines from the Samanids at whose court creative literature and poetry were most highly appreciated. only for the use of those who had remained in the Zoroastrian fold. On his death another Turkish slave who had married his daughter was elected Amir. There developed a violent reaction towards orthodoxy. trans. There is no reason to believe that force had been employed in the conversion of the Persians to Islam. the son of this second slave.r To their west were the Buyids who were also of Persian stock and claimed descent from a renowned family.lbn Isfandiar: History of Tabaristan. When the two languages came face to face after the Arab conquest of the country. and was for many years its sole patron.
we are told. Corresponding to a similar development in Western Europe. Ihiti. all prose i6-tdpoetry was written in Persian. as has been lately shown.> 'had no faith in Persian and the dialect of dari' which was to become the cultivated language of the country and which corresponds in name to 'King's English. And above all it was the language of the new Faith and compulsory for all forms of prayer. And under them there was a poet who 'like gentle rain cleansed the Persian tongue of chaff and corruption. The Saftarids. p. and in theological and philosophical works than in pure belles-lettres. so now changes in the political situation were creating a suitable atmosphere for the revival of Persian. which maintained correct relations with the Caliphs of Baghdad. The cradle of this vigorous national rebirth was in fact the court of the Samanids. religious and social considerations induced them to continue writing for long in both I 3 Cf. Although the literati must have been writing in Arabic for generations. It reflected the remarkable elan which was the distinguishing mark of the early Arabs. it gathers strength in proportion to the degree of Persian emancipation and self-assertion. there is a distinct period of bilingualism in the history of the Persian people and their literature. 44 45 . The few available source-books. and a whole series of compound words were formed one part of which was Arabic and the other Persian. Luhah.' But this is not strange when it is remembered that they were of Arab extraction and their patriotism was confined to political supremacy.'3 'Evidently in the early stages of its emergence. There was always a greater use of Arabic words in prose than in poetry. Arabic. 2. 4 • Cf. And just as the Reformation and the rise of European nationalism brought about the gradual disuse of Latin and the rapid development of the vernaculars. It persisted only in the seclusion of the countryside and the intimacy of the home. Consequently all the literature produced by the Persians.s Political. and its rapid growth owes much to their tender care and encouragement. Dowlatshah and 'Awfi. and they were inclined to make more use of their mother-tongue. the province most distant from Baghdad. but in style it did not ·differ from the Islamic and reflected the same spirit. And it is finally assured of success by the triumph of Firdowsi. who gives the movement its seal and justification. and which the Persians had long since lost. and not all the poems that have survived from that period are authentic. the value and influence of which can hardly be exaggerated. The revival of Persian seems to have begun in Khurasan. on the other hand. on the other hand.AVICENNA PERSIA IN THE TENTH CENTURY Persian had an extensive literature not only in prose but. It was enshrined in the Qur'an the like of which-even considered in its purely literary aspect-Zoroastrian religious literature did not possess. was the language of the conquerors and eventually became that of the administration throughout the Islamic Empire. It is a distinctive feature of this literature that the proportion of Arabic words seems to increase or decrease according to the taste of the patron and the political situation in the country. the vernacular that had suffered such long and rigid suppression was not in a very happy state.dealing with this period have not much to say on the subject of language. Admittedly there was some Christian Arabic poetry of a high order. Persian as a medium of literary expression was therefore easily suppressed. their aims and sentiments were undergoing a change. From the middle of the ninth century onwards. The Tahirids. and although there are hardly any traces of the early prose in whose existence some scholars believe. particularly at the court of the Umayyads in Damascus. in spite of the fact that its valuable pre-Islamic poetry was not extensive. being of Persian origin were more attached to the language of their forefathers. was almost entirely in Arabic-a situation analogous to the use of Latin in mediaeval Europe. It should not be supposed that under this dynasty. in poetry also. dna al-lisiinaln. and also according to the subject-matter. But when the Persian language finally emerged from this long period of virtual suppression-some early historians have insisted that this was done by force-some 80 per cent of its vocabulary remained Arabic.
· And an additional reason was that the subjects that occupied them most were theology. in particular with the Iliad and the Odyssey. illustrating thereby the bilingual stage. Levy. 975). continued to maintain its position as the directing centre of Islamic culture. Noldekee Das Iranisclze Nationolepos. but he too has his purple patches. . practically all that was written was in Arabic. they took the form of epic poetry which incorporated oral tradition and folklore into what survived of the semilegendary semi-historical accounts. They extended a happy welcome within the limits of their restricted domain to scholars and poets. the work as a whole merits comparison with the best European epics. It might be thought that judged by the standards of Aristotle's Poetics it fails because it is episodic. Under the Bfiyids. But under the Samanids the movement gained consciousness and determination. One of the rulers has himself left a good specimen of early Persian prosejr and some of them wrote prose and poetry in Arabic.delighted the most fastidious of Arab critics. and in the ancient traditions and festivals of the Iranian people. one important development was a growing interest in the pre-Islamic history of the country. In that literary movement of which he was the culmination in the field of poetry. Reflecting a Sasanian civilization with a feudal form of society that was rapidly disappearing. jurisprudence and philosophy. his only authentic work. and were addressed to a class usually well-versed in it. he succeeded as none other had done in reanimating the national spirit of a people already some three hundred years under foreign I cr. Later under the capricious eye of Sultan Mal. like Homer. Tabbiikh. By reviving the lays of ancient Iran. 1020). Qahiis-Nameh. edit. his contribution was twofold. Iqbal. who may have been a Zoroastrian by faith. • Tha'aIibi: Yatima ••• . though they were themselves of Persian stock. and the decline in merit from those Baghdad poets who. but that is not a universal principle. as had been the case in 'Abbasid days. A country squire born near Tus=-the modern Mashhad -living on the rent of his land with a daughter as sale companion. enlisting the support of men of learning. I The Shiih-Niimeh is a part-historical part-legendary story of the kings of Persia from the beginning of time to the Arab conquest. The Ziyarids of Tabaristan also took an active part in this literary revival. and died a fugitive from that enraged monarch. edit. he sought the court of Sultan Mahmud the Ghaznavid. he composed at least one thousand verses dealing with King Cushtasp and the advent of Zoroaster. which could be more easily treated in Arabic. rather than into Arabic t cr. though of Persian extraction.1mud the Ghaznavid.AVICENNA PERSIA IN THE TENTH CENTURY Arabic and their mother-tongue. as we have said. but he fell victim to the intrigues of the courtiers and was denied the reward that he felt was his due. Sure of riches and renown. And when they were put into verse. and who were wholly devoted to that inter-racial Islamic culture which the early 'Ahbasid Caliphate promised and only partially fulfilled. Such chronicles as had become by then rare. edit. 47 . The anthologies covering the period» show the extent to which Arabic continued to be used throughout Persia. may occasionally nod. They also illustrate the change in theme and in sentiment. based on prose works in the old Pahlawi tongue. At the request of one of the Samanid kings. For those who had put their faith in the rebirth of a distinctive Persian literature. it reached its full maturity. was Firdowsi (d. who in those days were often itinerants in search of fortune and fame. began to be translated into the gradually emerging new idiom. and who was eventually murdered by his Turkish slave. Biikharzi: Dumiat al-QOfr. Firdowsi. Thereupon he ridiculed the king and his slaveancestry in a merciless satire. Among the first authors in this genre was Daqiql (d. But the man to produce what by common consent is one of the great epics of world-literature. he laboured for some twenty-five or perhaps thirty-five years to write the Book of Kings (Shiih-Niimeh). Tatimmat al-Yatima. The reason for that was their close proximity to Baghdad which.
p. and also that of diplomacy and belles-lettres far beyond the borders of the country proper. and we find him saying: 'Henceforth I shall not die. In a modem study. • Glossar {ur Firdosis Schahname. This has caused a modem scholar to remark.. and fortified their resolve at a critical time in their history. . should be displeasing to us. but the Shah-Niimeh is a monumental work that in subject-matter and artistic merit stands far above the rest. and from the Caspian to the basin of the Indus river. It constitutes the first major breach in the linguistic unity of the Islamic Empire from south of the Pyrenees to Transoxiana. • Ibid. the Persian tongue became the official language at the court of the new conquerors. Daqiqi and Firdowsi had an illustrious predecessor in the person of Rudaki (d.. In France in 1549 Du Bellay wrote his Deffince et Illustration de la Langue Francoyse. 'cela symbolise Ie fait que Ie role proprement dit de I'Iran s'exer~ moins sur Ie plan politique et militaire que sur celui de la culture et de l'esprit. he gave new life and vigour to a language that had been declining with alarming rapidity.Although soon after the period under review the whole land was overrun.'3 Firdowsi himself was not unaware of the significance and the far-reaching results of his contributions. with a devastation rarely equalled in the annals of history. the poet has been able to use no more than 984 Arabic expressions.'1 These words and this sentiment could be the expression of the feelings of Firdowsi and his associates with regard to Arabic and Persian. 6. 251. to become servants to one tung for learning sake. the mutuqdrib . expressed with a felicity rare in those days. though not indeed to the same extent.' It will later be seen how Avicenna after him also made a special effort. cit. In the accomplishment of this task Firdowsi was indeed not alone.... Like Daqiqi. One unexpected feature of this rebirth of letters was its wide influence.. 3 Humbert: op. This Persian revival corresponds to the supersession of Latin. More important for the purposes of the present inquiry was Firdowsi's incomparable service to the Persian language in its post-Islamic form. 940). 49 . were a reminder of the hard times they had all passed through. When one realizes the extent to which Arabic had penetrated Persian. and sometimes called the Chaucer ofIran. and he reduced the use of Arabic words to the barest minimum. The sad reflections in which the work abounds. reckoned the first really great poet of post-Islamic Persia. 'I confess that the ancient Latin language is very copious and highly adorned. based on the exhaustive glossary of Wolff. he chose for his epic a strictly Persian metre.. but I do not see why our Tuscan of today should be I Humbert: Ohservations sur le Pocabuloire arabe du Chalmameh. however excellent. whose one thousand verses he had incorporated in his Shiih-Niimeh.! there is a highly instructive analysis of the Arabic terms occurring in the Shiih-Niimeh.2 It shows that in some fifty thousand lines of poetry.. the language of the Church until the Renaissance. first by hordes of Turkish origin and then by Mongols. the Shah-Niimeh made Firdowsi's countrymen conscious of their destiny. Alberti writes. Baugh: History of the English Language. I love Rome but London better. More than any other single work. Among the creative artists who founded the Renaissance in I cr. to contribute to this linguistic revival. with notable results.\ AVICENNA PERSIA IN THE TENTH CENTURY domination. held in so little esteem that whatever is written in it. And by making a deliberate attempt to use as few Arabic words as possible. For I was he who spread the seeds of speech again. In Italy as early as the year 1434. by the tide of national literature in the vernaculars which gradually overwhelmed it. Its social and cultural consequences were of great importance and proved farreaching.. I honor the Latin. p. alive I shall remain. but worship the English/a In this same spirit Firdowsi deliberately tried to replace Arabic terms by others of Persian root. And in England a Headmaster of the Merchant Taylors' School says: 'for is it not indede a mervellous bondage.. this remarkable achievement can be better appreciated.
Hlst. 8701£.. but the few remaining fragments are sufficient to show the simplicity of his style and the limpid purity of his language. a Ibid. and such care to find a method which for this branch of study would be both rigorous and just. Traveller. 98. Al-Biriini Commemorative Volume. astronomer. betray some familiarity with it.'> Beriini. Vol. 50 51 . which is the Chorasmia of antiquity. p.'3 The intellectual background of Beruni. pp. Sultan Mas'iid. In the field of science and scholarship. and teacher of Greek learning. he was induced to go to Ghazna. a Cf. where he transmitted to Indian scholars Greek thought in its Islamic form. Little of his poetry has survived. trans. 'It is rare before modern times to find so fair and unprejudiced a statement of the views of other religions. he is considered one of the greatest scientists 'of all time. And when Sultan Mahmiid conquered the principality. He reproaches the early invaders for having destroyed the civilization of Iran. to understand. the capital of the now powerful monarch.'3 Cf. Vol. like most other men of learning. geographer. The incensed Sultan explained that 'kings are like little children-in order to receive rewards from them. xliii. 4 Cf. Alhiruni's India. of Persia. then called Khawarizm. Included among them were Christian physicians versed in Syriac and trained in Greek philosophy. Ibid.• . According to an anecdote. just opened to the Muslim world. always trying to reason. his Canon Masudicus on astronomy. so earnest an attempt to study them in the best sources. Sultan Mahmiid twice commanded him to prophesy. p.' Born of Persian stock in Khiva.. mainly towards the east. the most celebrated poet of the Samanid period. and no new translations directly froin the Greek are heard of till modern times-indeed the knowledge of that language must have become extremely rare. he joined the council of state of the local prince. 160. I Beriini was a man of scholarly spirit and outlook. It would have been far better for him on that day if one of those two predictions had been wrong. mathematician. 'In astronomy he seems by his Canon Masudicus to represent the height. Yet both Beriini and. a contemporary of A vicenna who entered into correspondence with him and was closely connected with his associates and fellow-philosophers. historiographer. A vicenna. had driven away. he delights in comparing the different religious beliefs. the end of the independent development of this science among the Arabs. Beriini (d. Brockelmann: GA. to a less extent. and he regrets that the conquerors killed off the priests of his own dear Khawarizm and its learned men and burned their books. Basically Islamic. and at the same time.AVICENNA PERSIA IN THE TENTH CENTURY Europe. the Mu'tazila and the adherents of the different heterodoxies.. 3 2. Sachau. refusing to accept any belief blindly or on the strength of tradition.t On his return he dedicated to the reigning king. it was deeply coloured by Greek learning in its Arabic form. Christianity and Judaism are such as to win him the gratitude and admiration of modern students of these faiths. And in Persia this mission was ably fulfilled by Rudaki. he was cast into prison. possibly acquired through association with certain Christian physicians who kept their company and shared their fate. Vol. The violent orthodox reaction that had set in in Baghdad. one should speak in accordance with their opinion. and above all to criticize. and because of their Syriac antecedents and their I Cf. Sachau.» and his accounts of Hinduism. who in the words of an early author. the poets were the chief among those who initiated and fostered the new spirit of awakening after years of torpor. 3 Browne: Lit.> Using the comparative method so rare in his time. I. or perhaps even before. I. 1048) occupies the foremost position. which is his greatest work. had no very easy life. Chronologie . and because in both cases his predictions turned out correct. p. Shortly afterwards he left for India.. The period of the translators was past. He also wrote an admirable work on the religion and philosophy of India. had 'no equal except in Avicenna' and of whom some twenty-seven works have survived+ reflects the state of knowledge and the various intellectual trends towards the end of the tenth century in Persia and Transoxiana. edit.L.
is able to talk patronizingly 'to him. Porphyry. Miskawaih was. adding that the books 'were in Greek and Syriac. but he is known chiefly for his ethics based on Aristotle and certain Persian traditions. In his book on ethics. Gabrieli: AI-Rerun! Commemorative Volume. as has been shown. as well as a physical restlessness that kept them continuously on the move. He ridicules the possibility of discussing the sciences in that dialect. worldly. and Miskawaih. like the others.s that the personality of both is best revealed. Arabic and Persian. 3 Cf. from Alexander of Aphrodisias. The whole volume is enchanting. was a Zoroastrian. and why slim men and women are usually more virtuous than the fat. and his grandfather. no one having access to them except the Christians. edit. and translate Indian books into Arabic and some works. Amin and Saqr. why jealousy is far worse among the learned than among simple people. why the ignorant pretend to greater knowledge. an insatiable intellectual curiosity. It is however in his exchange of ideas with Taw~idi. In his Eternal Wisdom (Ja. as recorded by the latter. Sanskrit. Aratos. with a strong Turkish admixture. But he wrote books in Persian also. and that he had in his possession a philosophical lexicon giving the names in Greek. 1030). Of the two outstanding intellectual figures at the end of the tenth and the beginning of the eleventh century. from Aristotle's Physics and Metaphysics. His historical works are voluminous. such as those of Euclid and Ptolemy. or possibly his father.s Mean. AI-Imtit ••• Cf. he is characteristically objective. a fearI Cf.AVICENNA PERSIA IN THE TENTH CENTURY training in Baghdad. Ammonius. chide him for self-pity and recommend forgiveness as a cure. as well as the problem of the Good. bilingual. A vicenna was rather scornful and with whom he had some sharp exchanges. Hippocrates. the Greeks and the Indians. and he left books in both languages. Another contemporary of whom. Some have claimed that Beriini could read Greek. and A vicenna was to follow the same practice. Tawhidi asks why those who preach contentment are so greedy themselves. In his youth in Baghdad he attended the lectures of Sajistani and befriended Tawhidi. Qifp. All that he himself tells us is that he used to go to a Greek to learn the names of the plants. Many were the Greeks who combined medicine with philoI 3 Kitiih al-$aidana. Syriac and Hebrew. was Miskawaih (d. who is the only person to tell us much about him. • Cf. and as between Persian and Arabic. On the question of languages suitable for translation. and not particularly intelligent. and so Tawhidi insists. reminiscent of the essays of Montaigne. a broad humanity. Taw~idi with all his accomplishments and wide interests finds himself neglected and almost destitute. justice. in which he quotes Aristotle.1 He was of Persian stock. AI-Hawiimil wa al-Slaawiimil. 331. and they were then translated into Arabic so that the Muslims could benefit from them/a While admitting that his patron Sultan Mahmud 'hated Arabic.' he himself was not prejudiced. He had the initiative to study Sanskrit.il). specimens of which have lately been found. • Cf. edit. far less gifted. Timaeus and Laws. In his writings he quotes frequently from Plato's Phaedo. Kitah a1-Saidana. from Proclus' commentary on the Timaeus. an Iranian dialect. 53 . from Arabic into Sanskrit. Syriac. or translated any of them into Arabic. They shared an almost total lack of racial prejudice. Meyerhof. the Arabs. Beriini chose science and scholarship and Avicenna medicine and philosophy. less devotion to truth. we are told. he discusses happiness.' he gives his unqualified support to Arabic. Eudoxos and even Homer. but in a secure and lucrative post. Galen. it may be presumed that they already knew at least some Greek. But.' Greek learning in its Arabic version constituted one of the mainsprings of Benini's thought. Galen and the Stoics. His mother-tongue had been Chorasmian.> there is no question of his having read these in the original. he spent most of his life at the court of the Buyids in western Persia. p. was incapable of understanding philosophy. in both of which he admits to being an 'intruder (dalch. virtue and sophrosyne ('iffa).vidan Khirad) he gives an expose of the concept of wisdom severally according to the Persians.
Ziid el-Musaferin. but when for some particular reason Persian was preferred. they were held everywhere in high esteem. and treated with great respect by rulers and kings even when of foreign extraction or of a different faith. edit. It is known that Razi made notable contributions to medical literaturej! and there were others in Persia from some of whom important medical works have survived. Usually trained in Baghdad.) I 3 cr. and.L. and the tradition persisted among the Islamic peoples. In fact Persian names of drugs and diseases had entered Arabic from very early days. Siddiqi. Syriac and Persian.. Supp. and taught philosophy to a small circle. Brockelmann: G. Supp. and brought up and educated in Baghdad. Browne: Arahian Medicine.s and shares with Avicenna the credit of being one of the' creators of Persian philosophical prose. 378. 1061) was born in Balkh. cr. Kitiih a/-Almia ••• . a number of them in Persia and Transoxiana. When Sultan Mal}. In addition to carrying on his medical practice he wrote books. the difficulties involved did not prove insurmountable. He returned to his native land as a 'propagandist (da. p. The Persian names may also be explained by the influence of the medico-philosophical school of Gundishapiir. A gifted poet. whence some celebrated teachers were deliberately transferred to the new capital of Baghdad by the Caliphs. Among them was a compendium called The Hundred which became a manual of medicine used allover Persia. I. and may possibly have been his teacher in some of the subjects that were of interest to both. and became a Muslim towards the end of his life. cr. for whom medicine was a profession and philosophy an intellectual pastime.s There were also compilations on pharmaceutical preparations. A vicenna had a high opinion of him. Brockelmann: G. or after the name of the suburb in which he lived and practised. • Baihaqi: Tatimmat ••• .'! He lived to a good old age. and he coined certain terms from pure Persian roots that can be profitably used today. and was thus a countryman of A vicenna. p. were numerous and scattered all over the Islamic world. • cr.miid in Ghazna.'i).miid ordered the prince of Khawarizm to send him the celebrities who had gathered at his court. Na~ir Khosrow (d. There were many drugs and diseases that retained their Greek names. died in a sandstorm. Some mention may also be made here of a much younger contemporary who in his way was quite a remarkable figure. born in Gurgan. so called either because he was the son of a wine-merchant. 54 edit. I.3 The language employed in these manuals was usually Arabic. 13. 55 . Seligmann.A. and in one place says. partly because many of the physicians practising were of Persian and Syriac origin-and the Syriacs of Baghdad were very much Persianized through their religious centres in that country. Ibn al-Khammar (the son of Khammar). s cr. (The time has now come when the Persians must develop a philosophical language of their own. Masihi joined Avicenna in his flight. was a Christian educated in Baghdad. 4~J. 'may God grant us to meet him.A. 4 Safar-Namek. He visited the court of the prince of Khawarizm.' wrote a delightful book of travel. In that necessary task they will find him very helpful. as will be told later. twelve of which are mentioned by Beriini. if not from exactly the same district. p. his extensive travels took him as far as Egypt where he was converted to the Isma'ili heterodoxy.. and stayed there until he was carried off together with Beriini to adorn the entourage of Sultan Mal}. 3 cr. These physician-philosophers.L.'> Another physician-philosopher was Abii Sahl al-Masihi (the Christian). He soon became very intimate with Avicenna. either to benefit from him or to benefit him. so that medical terminology really consisted of Arabic with a large admixture of Greek.AVICENNA PERSIA IN THE TENTH CENTURY sophy. and as the author of many I medical works became known as 'the second Hippocrates.s He returned to his native country and was welcomed by the prince of Khawarizm who was then at the height of his power. There he gained his living by his profession. FirJaws al-Hikma.s His terminologyis even more rich than that of his predecessor.
I Cf. a centre of religious and intellectual life. also the seat of a large Buddhist monastery and since the Arab conquest a centre of Islamic studies that produced some eminent theologians. it was for a.H. Its hybrid nature is especially marked in its hte~ture and philosophy. Bal'ami. Of these Ibn 'Abbad was a distinguished poet.overts ancient glory under the Samanid o i ~I1. depending on the circumstances. an old Iranian city known to the Chinese as Pu-ho. This was the site. for reasons that are not hard to guess. the minister of the Samanids. Buddhism.. philologist and wit at the court of the Buyids in western Persia. This h~s often caused a dichotomy in Ideasthat can be explained onlywith reference to the history of the country. but ?oth are always pres~nt. the ancestor of the most powerful. He was such a lover of books that when the Samanid king invited him to become his vizier. though much from the collection has since perished.of the Nowbahar. Thus the Persian Renaissance had its roots in both Islamic culture and the ancient civilization of Iran. and with a conspicuous constancy has persisted down to modern times. T and an intellectual and religious capital.AVICENNA No account of this creative period is complete without a reference to the chief ministers at the court of the various rulers ~ho c~mpeted with one another in literary accomp1ishment.and m their patronage of men of letters. I. are based on an autobiographical narration which he himself chose to dictate to the man who was his companion and pupil of twentyfive yearst (about whom more is told hereunder). Ibn al-'Amid too was ~ writer of note and a stylist imitated by many authors. From Balkh the father of Avicenna moved to Bukhara. Sometimes one. We are indebted to him for his wise measure of having the works of Rlizi collected and copied by his pupils.p'~riodthe centre of Hellenicculnire.Nestorian Christianity and finallyIslam met. Manichaeism. Here Zoroastrianism. pp. Abu 'Ali al-Husain ib_n_'A~(:I::. one of his excuses for declining was that four hundred camels would be required to transport his library alone. It is to be noticed in SUfismand such religious movements as the Isma'ili heterodoxy.the.l!!~. As the.was born in August 980 (Safar.seat. pp.Allah ibnHasan ibn 'Ali ibn Sina. 2. Vol. sometimes the other element predominates. able and enlightened minister at the court of the Caliphs in Baghdad.of. Usaibi'a. 57 . His father was from Balkh-a city known to the Greeks as ~~~!ra. A galaxy of poets and men of learning were already contributing their share to this brilliant epoch in the history of Persia and Transoxiana.rendered an invaluable service to the emerging language by translating the voluminous history of Tabari. the epithet 'the glittering' in Middle Persian literawith t.) in a large village near Bukhara called Kharmaithan (The Land of the Sun). and whose name echoed in the cloisters of many a mediaeval monastery.Graeco-Bactrian kings. then lost its importance for a wliile~' nly_to !"¢c. At . and its issue was a ~ombination of ~oth. 413 If. Qifp. his was an important commercial and political metropolis.dGhaznavid dynasties. specimens of which are still extant. which by way of Hebrew became Europeanized into _Avicenna.at the head of which was Barmak. ' CHAPTER II V LIFE ALL AND WORKS OF AVICENNA accounts of the early life of the man whom Chaucer's Doctour of Phisik was so proud of having read. the renowned Buddhist monastery visited by pilgrims from far-away China. 370 A. 2 If. But he rose destined to shed an abiding light far beyond his own horizon. A. All this goes to show that Avic~nna was not a lone star.
~ssures that us he did not find it 'a difficult. and must therefore have been a man of some standing. There he married and had two sons of who~_~ vicenna was the elder.' he says. and proceeded to -read all the available hooks on the subject. The origin of the father is not quite clear. Avicenna's father was appointed as a local governor in Kharmaithan. When he was only ten years old he had reacf the Qur'an and some bdle$-}ettrlJi. Much Peripatetic and Stoic thought found in his writings stems from this source. who had ascended the throne in 977 at the age of thirteen. and from then onwards A vicenna read the texts himself with the aid of commentaries. and visiting an old ascetic from whom he learnt the methods of religious argumentation. Presently a man by the name of Nateli. Turks and Persians have in tum claimed the son. and all marvelled at his talent. Together they went all through the elementary parts of logic.and met<iphysics alone. suggests that she was Persian. The lessons started with the Eisagoge of Porphyry. When Nateli left for Gurganj. to his father. They asked him to join them in their discussions on philosophy. son of Mansur. a pure Persian word meaning Star. The religious atmosphere of his home was not orthodox-an important point that he himself tended to conceal. science. As the vast majority of the inhabitants of Transoxiana at that date were of Iranian stock. Avicenna's father immediately engaged him to teach his son and invited him to stay in their house.Next he took up the Almagest of Ptolemy.' and that he excelled in it in-i-very short time. The view that he was of Chinese lineage which is based on the assumption that the whole region was formerly a centre of Chinese rule where many of their people had settled. Avicenna deliberately avoided Turkish patrons. 'My father. reading the texts and seeking help from commentaries. He _~lso continued his study of religious law and dis- 59 . Nul). H~ often depended upon them for his understanding o(Pl<!to an~:t\r~~~~le.r. supposedly of Hellenistic authors translated into A. 40) stresses that both Avicenna and his father were in the habit of reading the Epistles of the Brethren of Purity. To this may be added the observation t. and here Avicenna's early form~~ic:~ge begins. an~_hrot?er discussing the soul and the intellect 'after the manner m which they [the -lsma'ilis] expounded them.hat throu~hout all his wanderings. and at the same time he was studying Muslim jurisprudence by himself. and the great Turanian predominance does not begin till after the Mongol conquest. At this stage he decided to take up medicine.Similarly with E_l!C?_I!d: read parts with his teacher he and-the rest independently~. !l_e_. He was sent to a certain grocer who was in the habit of using that form of calculation to learn Indian arithmetic. 'was one of those who had responded to the invitation of the Egyptians [the Fatimids] and was counted among the Isma'ilis. all Iranian origin seems the most probable. and caused him to advise the father that.AVICENNA LIFE AND WORKS OF AVICENNA this time it was the capital of the Sama~id ruler.anCl sought the courts of Persian rulers. the second. but which helps to explain some of the difficulties of his life. The family returned to Bukhara. and one day. No source tells us whether or not he was an Isma'ili also. using methods of treatment often extrem~ly practical. Avicenna took up the naturalsciences . geometry and Indian arithmetic. the hQY shouldnot engage in any other occupation but learm~g. is rather far-fetched. the young pupil set about verifying that definition in a manner that deeply impressed Nateli.c!hic. and often it was beyond the powers of his teacher to li'eIj)@m. p. and her name Setareh. professing a knowledge of philosophy. 'I Heused to listen. having heard his teacher define a genus. !i 58 he felt he could not assent to their arguments. As to his mother: she came from the nearby village of Afshaneh. came to Bukhara. and which had become a cultural and commercial thoroughfare between Persia and China. but he does not say if he ever responded to the invitation.•• . There is at least no reason to believe that he was an Arab. These supplementary books were to prove an important influence on his own works..' but he hastens to add that I Baihaqi (Tatimmat . Arabs. he tells us.
AVICENNA LIFE AND WORKS OF AVICENNA puta~~n. read . Next. and when sleep began to overcome him. fell iII. . Whether iliisstatement is true or due to the excessive zeal of the disciple who recorded it. he took a glass of wine and went back to work again.' they claimed. his genre of writing had gone into common use T since Alexandrian times. but today I am more mature.. and he wants to explain just how it came about that he became addicted to drinking. whereupon Avicenna wrote al-lfiifi/ wa al-Ma!z!ii. it some forty times. and prayer gave him insight in solving his problems. as well as-iiwork on ethics called al-Birr wa al-Ithm (Good Work and . he says.gave. much interested in jurisprudence. or when he felt weak. D~ring the following eigh!(!_enmonths he went over 10_g!c nd a th:r-~!:!~~~ problems otphil9 -ag.ii~:Durini this period. he tells us. Historians may well search for the perpetrators and their purpose.' (Comp~ndi:t:lm_).. when in answer to the request of a certain prosodist. I read these books.1 (the (the Import and the Substance) in about twenty volumes. "Thenabruptly his life entered fl. he was sixteen years of age. It might well have been connected with the racial and religious struggle that was going on at that time in the capital of the Samanids and that ended in their downfall. to met~p~y~~<::s lIe took up the M~taphysica of Aristotle. of whose wide reading they had heardmuch~-s~ be summoned. He was duly sent for.with the others successfully treated the royal patient.YULof which he never made copies but presented it to his . --According to his own account. the natural sciences and mathematics. By then. Each apartment was devoted to a special subject. one of his neighbours.since 'my memory for learning was at that period better than it is now. One day in the booksellers' street a broker off'erecrlifm a cheap volume which he bought only reluctantly. new phase. otherwise my knowledge is exactly the same and nothing new came my way after that.learned friend in the original.' This great library. and when he reached the section on Greek. and he went out to distribute alms to the poor in gratitude the next day.' This taking of notes was very important. A vicenna tells us. but he felt he must return. ~ the. but to his great disappointment still could not understand it. asked him to write a commentary for him. Whenever he found himself in a difficulty-he chooses to assure his pupil-he repaired to the mosque. the reigning prince.t_!01!_. hisphysicians sugg_~ted that _t\:vicenna. while he was still at Bukhara. and as a result became enrolled in his service. I accepted a post in 61 . taking notes of their contents. This he found to be a mansion of many chambers with chest upon chest of books in sophy-orice i 60 . he wrote a comprehensive book which heqllI~cl. In the evenings he sat by his lamp and worked late into the night._H])@ry of the Samanid rulers. andin collabC:>11l. He tells us 'my father died and my circumstances <:h'mgecl. and it will be seen that many of his works take that form. 'I saw books whose very names are as yet unknown to many-works which I had never seen before and have not seen since. collected by successive rulers all known for their passion for literature and learning. whereupon the whole purport of Aristotle's treatise was revealed to his mind. he did not sleep one night through. Unable to help him.~lll~ Majmii.By working in this manner ~~~~!~rec:lJc:>gis. It turned out to be a book by Farabi on the objects of the M~tsJ= ~ He rushed home and read it. He likes to assure his pupil that he is a religious man. It happened at this time that Nul) ibn Man!?iir. we are unable to say. Avicenna's first attempt at authorship was made at the age of twenty-one. This minor detail which he candidly relates is interesting. reducing every statement and proposition 'that he read into its syllogistic premisses and recording it in his files.himaccees. was soon afterwards destroyed by fire. and worked all day.I I I i each. ~p~ial permission. 'so that he could attribute the contents of those books to himself. A vicenna' s enemies-and he never lacked them -hastened to accuse him of firing the library. Hellenists must always mourn the treasures that were reduced to ashes in the lllira_ry_c:>f~ukhara.
Yet aga~n he does not tell us why 'necessity' forced him to leave Gurganj and embark on his peregrinations. The life-long friendship between these two men is not surprising~ ~is companion. but his words betray bitterness. his father's home-town~ and like him he apparently had no family attachments. He welcomed A vicenna and intro. where he died. pp. writing much later. and his later commentary on that subject in some twenty volumes-matters remote from his chief interests-were meant to assure his pupil of his religious conformity and of the fact that he never acceded to the Isma'Ili beliefs of his father and brother. and we find historians like Ibn al-Athir.' only to add immediately afterwards. From another source. Furthermore the Turks were such a menace to the Persian element that Beruni. but it happened meanwhile that Qabus was taken and imprisoned in a fortress. and we know from other sources that he was actually accused to Sultan Mahmud of being bad-am (of evil religion).AVICENNA LIFE AND WORKS OF AVICENNA the Sultan's employment. which if not entirely true is not pure fiction either. A salary was duly fixed for him which he describes as 'amply sufficient for the like of me. ' It is significant that even to his intimate friend and pupil. with their reference to the story of Joseph in Egypt. 'then necessity constrained me to move to Fasa and thence to Baward and thence to Tus.. And when my value rose. then Jajarm the frontier-post of Khurasan. A vicenna and a pa1l1ter by the name of 'Arraq. If after his father died he found it necessary to earn his living and for that reason enlisted in government service. The Turks were gaining the ascendancy and they must have frowned on the son of an Isma'ili. as the name shows. no more would Egypt have me. After this. It says that Sultan Mahmud was told that there were some highly gifted people at the court of the Ma'munid prince. then why was he 'obliged' to leave Bukhlira and submit his allegiance to a different ruler in Gurganj? These were troubledtimes at the court of theSamanids. In any case his departure from Bukhara was in unhappy circumstances. His arrival in Gurganj-a large and flourishing city along the banks of the Oxus-at first seemed fortunate and ofhappy augury. .we have a highly coloured account of the reasons that forced Avicenna to leave Gurganj. 76 fr• 62 63 . Khammar. then Shaqqan.~ went to Dihistan where I fell very ill. was a fellow-countryman. 'that they may have the honour ~f being received in our meetings and we may be pleased by their knowI N~: Cluzlziir Maqiila. who was somewhat in the same position. The minister of the ruling Ma'munid prince was a learned man by the name of Soheili. and marked the beginning of a most troubled period in his life._ duced him to the Amir. a mood also implicit in the surviving lines of his otherwise lost poem. It is not difficult to imagine that his enemies made capital of the heterodoxy of his family. The king thereupon sent a special envoy asking the ~rince to send him Beruni. In fact it is tempting to suppose that Avicenna's autobiQgtaphI(i1 narrative. levelling the same accusation against him in the most violent terms. Avicenna might therefore have become unwelcome for both racial and religious reasons. even though some of the Samanid rulers themselves had Isma'ili connections. who should be made to join his entourage•. Avicenna did not wish to expatiate on this episode. Juzpn being the western district of Balkh. dressed in the garb of a theologian with scarf and chin-wrap. with its emphasis on the study of Muslim jurisprudence and religious disputation at the feet of an ascetic. and was obliged to move fron1~!!khara to G~. Masihi. wrote a book entitled A Warning against the Turks. then Samanqan.' Here ends the autobiographical note dictated to Juzjani. then returned to Jurjan where Abu 'Ubaid al-Jilzjani made friends with me.Irganj. and I composed a poem on my condition in which there is a verse saying: And great once I became.. My entire purpose was to reach the Amir Qabus.. no one would care to buy me. and thence to Jurian (Gurgan).' This obscure passage throws little light on what must 'actually have taken place. though the tenor of the account is full of restrained self-pity.
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ledge and accomplishments.' The prince, who had suspected the purpose of the envoy even before arranging to receive him, called these men 'for whom he had provided all their earthly wants' and acquainted them with the probable intentions of Sultan Mahrmid. The Sultan, he told them, was very powerful and coveted his principality and he was therefore in' no position to anger or provoke him. Bertini, Khammar and 'Arraq, having heard much of the generosity of the Sultan, agreed to go; but Avicenna refused and Masil)idecided to keep him company. On the advice of the prince, they terminated their ten happy years in Gurganj, and left by night with a guide to lead the way. There is reason to suppose that it was primarily for religious reasons that Avicenna refused to comply with the wish of Sultan Mahmud, whose strict orthodoxy and ruthless treatment of the unorthodox had already become proverbial. This may well have been the motive of Masil)i also, who unlike Khammar had remained a Christian; and according to one account even Beruni went reluctantly. ,The story goes on to relate that Sultan Mahmudwas very angry when he heard of Avicenna's flight; that he ordered 'Arraq to make a portrait of him and that some forty copies were circulated throughout the land with strict orders that he should be arrested wherever found and sent to the Sultan under escort. Meanwhile Avicenna and Masihi who had left Gurganj witha relation of Soheili, the minister, as guide, wandered from village to village until on the fourth day they were caught in a violent sandstorm and completely lost their way. Masil)i could not survive the excessive heat of the desert, and died of thirst, assuring his companion, however, that 'their souls would meet elsewhere.' Avicenna together with the guide found his way to Baward 'after a thousand difficulties.' From there the guide returned, and Avicenna went on to Tus. It is thus seen that the itinerary corresponds with his own account as recorded by his pupil, and that this account may therefore well be true. The story is then taken up by Jiizjani. 'From this point; he
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says, 'I mention those episodes of the Master's life of which I was myself a witness during my association with him, up to the time of his death.' In Gurgan, Avicenna seems to have been well received. One man 'who loved these sciences' bought him a comfortable house next to his own and lodged him there. And Jiizjani used to visit him every day, to read the Almagest with him, and to listen to his discourses on logic. He here dictated a book on that subject which he called al-Mukhtasar al-Awsat (The Middle Summary) which his pupil took do~n. He aiso wrote others; among them aI-MaMa' wa al-Ma'iid (The Beginning and the Return), and al-Ar~ad al-Kulliya (The General Observations) composed in honour of his benefactor. He began writing the first part of al-Qiiniin (The Canon), his chief medical work; and one that he called Mukhta~ar al-Majisri (Summary of the Almagest), and many other tractates on similar subjects of interest to him and to the man who had been so good to him. After a while, however, he chose to leave Gurgan and go to Raiy. Again the reasons for that decision are obscure. Admittedly he had originally gone there with the hope of offering his services to Qabiis, the celebrated Ziyarid prince and man of letters; and had instead found that the unlucky ruler had been betrayed by his army chiefs and died while imprisoned in a fortress. Yet the philosopher had been welcomed in that place, had been offered a home by one of the townsmen, had found a devoted friend and pupil in the person of Juzjani, and had occupied himself with the writing of books. What then made him leave? Was his departure again due to some religious hostility towards him or simply to his own ambition and the hope of doing still better for himself? Raiy, the ancient Ragha, some five miles from present-day Tihran, had peculiar attractions. It was an old centre of communication between east and west Iran; associated with Zoroaster . and the twelfth sacred place created by Ahura Mazda, with accommodation for the three estates of priests, warriors and cultivators. It had been fortified by Darius and destroyed by
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Alexander; rebuilt by Seleucus Nicator and named Europos; reconquered by the Parthians and calledArsakia. It was from this city that the last Sasanian king issued his farewell appeal to the Iranian nation before fleeing to Khurasan. Here the Umayyads handed over power to the 'Abbasids, and here Hartin al-Rashid, the Caliph, was born. The population though predominantly Persian included men of many lands; and the bishops of the Syriac Church in Persia had made it their seat. In 925 when the Biiyids had established themselves there, Raiy was 'one of the glories of the land of Islam' and possessed a very large library. Under Fakhr el-Dowleh, the Buyid prince, it had become a great centre of learning; and the two accomplished ministers of this dynasty, Ibn al-'Amid and Ibn 'Abbad, had made it a centre of attraction for men of letters. When Avicenna came to Raiy, Fakhr el-Dowleh was already dead, leaving a son by the name of Majd el-Dowleh, still only a child, and the country was ruled by his widow-a princess in her own right-known as al-Saiyyida (the lady). This able and courageous woman had refused to hand over power to her son when he came of age, and had kept Sultan Ma1}.mudt bay with a the warning that should he conquer her principality he would earn the scorn of the world as the mighty king who made war on a woman. _--. Avicenna, as Jiizjanitells us, offered his servicesto the Saiyyida and her son, and was welcomed because of the favourable letters of introduction he had brought with him, Who gave him these letters, he does not say. Majd el-Dowleh was not a happy man at the time. He had tried to win back power and establish his rightful position, but had failed. He had therefore taken to the pleasures of the harem and of literature. We are told that 'he was overcome by melancholia and the Master applied himself to treating him.' Avicenna remained for two or three years at Raiy, during which period he composed the Kiiah al-Ma'ad (Book of the R~t1!rp).Then trouble once more overtook him. The city was attacked by Shams el..Dowleh, a brother of Majd el-Dowleh, 66
r
and again 'circumstances conspired to oblige him to leave Raiy for Qazwin, and from Qazwin he proceeded to Hamadhan.' Although the pupil is careful to conceal the 'circumstances,' Khondamir-an historian of later date-informs us that Avicenna infuriated the Saiyyida by insisting on the legitimate rights of her son in the dynastic quarrel between the two. This had become a local issue of some importance and the moral indignation of the philosopher could not be allowed to interfere. In Hamadhan yet another phase begins in the life of Avicenna. He decides to take an openly active part in local politics; and placeshimself at the disposal of another influential lady, who may have been the wife or the favourite of Shams el-Dowleh, 'in order to investigate her finances.' By this means he becomes acquainted with the ruler and is summoned to court to treat him for an attack of colic. The treatment proves successful and he departs 'loaded with many costly robes ... having passed forty days and nights at the palace and become one of the Amir's intimates.' In a war against the Kurds, he accompaniesthe prince as his personal physician; and although the expedition. proves a fai~ure, he succeedsin winning the favour of the Amir, and on their return to Hamadhan is appointed a vizier with all the powers of that office. His debut as a political figure and State administrator, however was followed by further trouble. The army for some reason refused to have him, 'fearing for themselves on his account' whatever this statement means. They could not in any way be pacified and 'they surrounded his house, haled him off to prison, pillaged his belongings.... They even demanded that he should be put to death; but this the Amir refused, though he was agreeable to banishing him from the State, being a~ious to conciliate them.' The fury of the army was such that Avicenna .had to go into hiding for forty days in the house of a friend. However, Shams el-Dowleh was again attacked by coli~ and he . was again sent for. When he appeared at court, the Amt~ apologized profusely for what had occurred. For a second time and with great ceremony Avicenna was appointed vizier.
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At this juncture Juzjani suggested that he should not neglect his writing, and urged him to undertake a commentary on the works of Aristotle. The reply is revealing with regard to A vicenna' s attitude and outlook. He said he had not much time at his disposal, but 'if you agree that I should compose a book setting forth those parts of the sciences that I believe to be sound, not disputing therein with any opponents nor troubling to reply to their arguments, I will do so.' He then began work on the physical section of the Kitab al-Skifa (The Book of Healing) _ which is the longest of his extant works. He had already started on his Qaniin (Canon) of medicine, and here he finished the first book. Every night he held a circle of study at his home for his pupils. 'I would read the Skifa,' Juzjani says, 'and another in turn the Qaniin. When we had each finished our allotted portion, musicians of all SOrtS would be called in and cups brought out for drinking, and in this manner we spent the rest of the time. Studying was done by night because during the day attendance upon the Amir left him no spare time." A different accounts of his daily programme relates that during the period that Avicenna was a vizier, he used to rise before dawn every morning, write some pages of his Skifo, then call in his pupils and with them read some passages from his writings. By the time he was ready to leave the house, all those who wanted him to attend to their work were waiting outside. At the head of them all he rode to his official divan and dealt with affairs of State till noon. He then returned home and invariably entertained a large number of guests to lunch. After the siesta he went to present himself at court, and alone with the Amir discussed matters of importance. These two accounts which may well be taken together as complementary show that he was a man of extraordinary industry and varied interests. They also reveal some of the more personal sides of his life. Evidently he did not hesitate to display publicly his love of music and wine, and to share them with those who
I
Qifp, p,
420.
a
Cf. Ni~:
Cha"-iir Maqiila, pp. 82-3.
partook also of his intellectual pleasures. Such conduct must have seemed scandalous to his colleagues in the Government, particularly in the rigorous Islamic society in which he lived. But all throughout his life he appeared to find satisfaction in completely disregarding what the public thought and said of him. This unconventional way of life he continued for some time and it may have been the source of much of his unpopularity. In the meantime the restless Amir decided to go to war again, and took Avicenna along with him. A severe attack of colic seized the prince during what proved to be an exhausting campaign, and he refused to follow the directions of his watchful physician and take sufficient rest during the intervals of fighting. The army, apprehensive and fearing the consequences of his death, decided to convey him to Hamadhan, but he died on the way. The son of Shams el-Dowleh was thereupon sworn in as Amir, and the army petitioned that Avicenna should continue as chief minister. This Avicenna declined and entered into secret correspondence with 'Ala' el-Dowleh, the ruler of Isfahan, offering his services. The reasons for this change of allegiance are not clear. It may be supposed that Avicenna's relations with the army were strained and his past experiences not altogether happy. Fearing the consequences of his refusal, he went into hiding in the house of a druggist. There again the pupil who seems to have valued his intellectual accomplishments far more highly than his political acumen, urged him to profit from this enforced leisure and finish writing the Skifo. Accepting this proposal, Avicenna summoned- his host and 'asked for paper and ink; these being brought, the Master wrote in about twenty parts of eight sheets each, the main topics that he wanted to discuss, in his own hand, and he continued writing for two days until he had enlarged on all the topics without once asking for any book or referring to any text, accomplishing the work entirely from memory. Then -he placed these parts before him, took paper, and pondering on every question, wrote his comments on it. Each day he wrote fifty leaves until he had completed the whole of the natural
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' At court he was received very cordially and with all due ceremonial. with the exception of the books on animals and plants. XIV. and wrote scornfully: 'My going in was sure. After suffering many hardships they reached the gates of Isfahan. On his return the prince did his best to win back the allegiance of Avicenna and promised him handsome rewards.' In the same way he introduced some new examples into Euclid. probably something which had never been attempted since the Arab conquest of Persia. the Son of the Vigilant)' and the Kitab al-Qulanj (The Book of Colic). and two slaves. While accompanying the Amir on an expedition.' Meanwhile he had been accused of corresponding with 'Ala' el-Dowleh and a search for him was instituted. where his friends together with the courtiers 'Went out to welcome him. He also began with logic and wrote one part of it. One night while discussing the imperfections in the astronomical tables based on ancient observations of the stars. sought refuge in the very place· where Avicenna was confined. in the Persian language. Danish-Nameh ye 'Alii'i (The 'Ala'i Book of Knowledge). assuring him the necessary funds. and thedefeated" ruler. to discuss scientific and philosophical topics.' the (A. His enemies betrayed his whereabouts and he was cast into prison in a fortress. and eminence and honour.la' el-Dowleh attacked and captured Hamadhan. and 'robes were brought and fine equipages. I cr.' But after some four months he did go out of that fQrtress. He immediately started work and deputed Jiizjani to select the instruments and engage skilled assistants.'b. Faddegon in Arclzeion. as you have seen.' These were indeed the best days of his life. In his commentary on the Almagest 'he introduced ten new figures into the different observations. the Amir asked him to compile new ones. after the name of his patron. Nor had he been idle while in the fortress. My going out is what many will doubt. under the section dealing with the celestial sphere.~of the Amir. By this time he had become one of the intimate C-~urti(. 70 71 . Vol. and Avicenna accepted the hospitality of a friend and busied himself with the completion of the logical section of the Shifa. all dressed as Sufis.yibn Yaqran (The Treatise of Living. The al-Adw. and when the latter decided to attack Hamadhan=-city of unhappy memories for Avicenna-he did . but all in.AVICENNA LIFE AND WORKS OF AVICENNA sciences and metaphysics. for there he had written the Kitab al-HiJay~ (The Book of Guidance) and the Risalat Qa.yat al-Qalbiyya (The Cardiac Remedies) he had composed when he first came to Hamadhan. they all returned home. and avoiding politics and its pitfalls. 193:1. in security. who valued Avicenna's talents highly. Many old problems were thus elucidated and the imperfections were found to be due to the fact that the observations had been made at irregular intervals and on different journeys.' and at the end. together with his family. not remain behind. his own brother.' Here in Isfahan he occupied no official position. There he again took to poetry. 'he had things that had never been discovered before.' He was lodged in a large house and 'his apartment was furnished and carpeted in the most sumptuous manner. and in the introduction to his Persian logic he expresses deep gratitude to his patron for granting him 'all his wishes. When 'Ala' el-Dowleh withdrew with his army.. he composed remaining parts of the Shifa together with an abridgement of the whole work which he entitled Kitab al-Najat (The Book of DelivelClnc:e). (. At the first opportunity he slipped out of the town in disguise accompanied by Jfizjani. He now set about completing the Shifa.ij>oveypTJ}'oprk for learned men of all classes. and in arithmetic 'some excellent refinements'. who calls it un travail tres soigne. Pro 38 a 41) lfaiy Yaq{an (Tazart). and in music 'matters that the ancients [the Greeks] had neglected. he devoted his entire time to writing. 'Ala' el-Dowleh.' At Isfahan he also wrote his first book on philosophy .vain. We are assured that 'at these gatherings he proved himself quite supreme and unrivalled in every branch oflearning. decreed that every Friday evening a meeting should be held in his presence I cr. This work he called.
While thus occupied he bids Juzjani and his brother to sit and drink with him. and he at once took up a thorough study of Arabic grammar and literature. calls up Juzjani and gives him what he had written during the night in some fifty sheets.AVICENNA LIFE AND WORKS OF AVICENNA At this stage of his narrative Jfizjani. He showed his intolerance of heterodoxy in a ruthless manner. yar-Shiipr. Some three years later he composed three Arabic poems full of rare words. the Batinis and the Mu'tazelites. and still another in the style of al-Sabi. c* 73 . p. later placed at the beginning of the Najat. where a group of scholars had taken exception to some of its statements. • N~im: Sultan Mabmud ojGhQ{na. In the morning he. the son proved unequal to the task. but not sufficientlywell read in philology as to be able to please us by the expression of your views. Instead he used to look up the difficult passages and the complicated problems and see what the author had to say. 83.» he 'began to persecute the Carmathians. Badawi: Ans!u 'ind al-'Arah. another in that of Ibn 'Abbad. orders them to depart. breaks off to observe that' one of the remarkable things about the Master was that I accompanied and served him for twenty-five years and I did not see him take up a new book and read it right through. but certain fragments have survived. conquer the whole kingdom and dispatch its ruler and his son as prisoners to India. the pretentious scholar was entirely baffled. immediately turned to him and said. One of the scholars present who was particularly proud of his knowledge of that language. then three essays. But after her death. 'You are a philosopher and a man of wisdom. and began reading extensively. and when they become drowsy. one in the style of Ibn al-'Amid. so as to discover the state of his learning and the degree of his understanding: Avicenna had never been a master of Arabic. sits there and by candlelight examines the points raised. 'I made hasteto reply so that the messenger should not be delayed. In the words of a modern historian. The judge of the religious court decided to send their objections together with a covering letter to one of the pupils of Avicenna.' One authority is quoted to the effect that 'fifty camel-loads of books are said to . who had been repeating what Avicenna had related. What purports to be a copy of that treatise has lately been published in Persia. It was after this incident that lie began a work on linguistics which he called Lisdn al-'Arab (The Language of the Arabs)-still only in the form of a rough draft at his death. This was destroyed by the invading army of Sultan Mas'iid.have been burnt under the trees on which the Carmathians had Cf. He had all these bound in one volume. and presenting it to the Amir asked that it be passed on to the learned man who had administered the rebuke with the request that he should determine the value and find out the authorship of a volume that had been found while he was out hunting. he expressed an opinion on a difficult linguistic question. saying. Avicenna immediately asks for paper and ink. had the binding rubbed and soiled. This the pupil did just as the sun was setting on a summer day. I Edit.' During this period the Kitab al-l~af(The Book of Equitable Judgement) was also written. asking him to present them to his master and elicit an answer. One day when in the presence of the Amir. orders drinks to be laid out. To the satisfaction of Avicenna and all those who had witnessed the disputation. He injudiciously asked the assistance of Sultan Mahmtid who seized the long-awaited opportunity to send an army. A copy of this had reached Shiraz in southern Persia.' The ruler of Raiy had been an astute lady who had usurped the rights of her own son and kept the ambitious Sultan Mahmud at bay. . I I Another story concerns an essay on logic written in Gurgan and called al-Mukhtl2!ar al-A~ghar (The Smaller Epitome). He ordered anthologies from Khurasan=-in those days a great repository of Persian and Arabic books-and various literary works. and thousands of them were gibbeted.' This rebuke greatly annoyed Avicenna. and while a general conversation is in progress. stoned to death or carried in chains to Khurasan to languish in captivity.
at the age of fifty-eight. was thus consumed in an instant to satisfy the enthusiasm of the puritan warrior. is a semi. was seized by a severe attack of colic. The autobiographical note and what his pupil had to add are obviously neither complete nor convincing. Nevertheless he accompanied his patron in his flight. Was it himself or his pupil who thought it best to leave certain things unsaid? Casual remarks by later authors fill few of the gaps. and it may be presumed that Avicenna accompanied him. 160. The book that in our view gives the best background to much that Avicenna had to suffer. On the way he had a severe relapse. 'I do not know whether purposely or by mistake. but one of his slaveswent and threw in a great quantity of opium.It was then that he gave up all treatment and took to saying.. 74 75 .AVICENNA LIFE AND WORKS OF AVICENNA been gibbeted.' He lingered for a time in this condition and died not long after his return to Hamadhan. and he consumed the mixture. It was then that his house was plundered and his library carried off to Ghazna. this being because they had robbed him of much money from his treasury. his body' had no longer the strength to repel the disease.1 A.fighting a Ghaznavid army chief.. Once again 'Ala' el-Dowleh marched on Hamadhan and again Avicenna accompanied him. he realized that his strength was ebbing fast.H. and helps to explain some of the obscure motives that influenced the course of his life. ~ e are told that in the year in which 'Ala' el-Dowleh was. and one day when he desired to be injected with two measures of celery-seed.' r Such was the state of his health when Avicenna was carried into Isfahan.lmi1tl of Gh. with the result that his intestines were ulcerated. a conjurer of evil spirits. and this bare outline of an eventful life does not give a full picture of the man and all that he went through. Accounts of the sequence of political events during this period are contradictory.'> The fall of Raiy had made the position of 'Ala' el-Dowleh in I~fahanvery critical. and entrusted to his son the task of conquering all the Biiyid possessions.). so there' is no use trying to cure my illness. Fearing the prospect of being left behind if the Amir were defeated. and they desired to do away with him so that they might escape the penalty of their actions. is incapable of managing me any longer. When he felt a little better he once more attended the court of the Amir. one of the physicians attending him put in five measuresinstead. 'Ala' el-Dowleh fled. Jiizjani adds. but there is always a feeling that something has been kept back.' He continued to treat himself by injections. * * * * N~: Sultan Ma/. Nor is the motive for reticence always clear. 1037 (42.. When Mas'ud." And he concludes that 'An invaluable store of learning. so that in popular Arabic. 'the manager who used to manage me. He was buried outside the town in June or July.8 A. only to be destroyed about a century later by the invading Ghiirid Turks. the equally ambitious son. and when they finally reached their destination. No one would be expected to make a careful record of the events and circumstances of such a man's life. He continued to prescribe for himself. He did his best to conciliateSultan Mahmud. p. and in one day injected himself eight times. which the liberal policy and scholarly zeal of the Buwaihids [Buyids] had accumulated in the course of years.H. while in the company of the Amir. though he Was so weak that he could hardly stand on his feet. Avicenna took heroic measures to cure himself. and the dates not very reliable. but the latter was adamant. and at their next stopping-place 'the epilepsy which sometimes follows colic manifested itself. Persian and Turkish literature he often figures as a sorcerer and magician. and his detractors succeeded'in spreading all sorts of derogatory stories about him even during his lifetime.Q{na. and is said to have indulged in excesses for which he again suffered in health. entered Isfahan in 1030 (42. Avicenna was never a popular figure. 'He also took mithridatum for the epilepsy. Avicenna. • Ihid.' The excess> of celery-seed aggravated the abrasions.).
and it is clear that even a friend and disciple of twentyfive years did not enjoy his full confidence. With this situation in mind. and this may have been one reason why his pupil urged him constantly to devote most of his time in writing. a particularly endearing personality. It was associated with the Turkish influence. One relates that when supposedly in hiding. and was immediately recognized by a man.' He ridicules Miskawaih and his pitiful limitations-and thereby provokes the rather significant retort that he would do well to . therefore. Two different sources. Yet Avicenna was no recluse given to solitary contemplation like Fariibi. And when he spoke all those present listened attentively. he indulged in sexual relations far more than even his strong physique could stand. he is hounded from town to town for reasons that he does not care to tell. All these facts imply a deep-seated unhappiness. It is not surprising. We are told that even in failing health he did not abstain. and the ruthless suppression of all forms of unorthodox movement and belief. And the other testimony to his fine appearance is in an account of how he attended the court of 'Ala' el-Dowleh in Isfahan. and extended in time from before the days of A vicenna till long after him. 76 77 . and a fundamental dissatisfaction with his lot. Schefer. As a man of excessive passions. in some respects. We suppose that he must have learnt early in his life to suppress and conceal. p. 'I could easily tell. I had heard so much about your remarkable face and attractive appearance. In page after page he describes the persecution of the followers of the Isma'ili heterodoxy. not given to moderation. and accomplishment and wit. edit.AVICENNA LIFE AND WORKS OF AVICENNA historical semi-political tractate' by a renowned statesman who was eventually assassinated. This puritanical revivalism and rule of rigid orthodoxy was particularly strong in Transoxiana and on the eastern borders of Persia. A sense of futility and frustration seems to cast a shadow over all his doings. and his family had lived. and that may have made him unhappy. He dismisses Razi's philosophy as the lucubrations of a man who should have stuck 'to testing stools and urine.'2 He could not have been a modest man. He tells us that in Gurganj he chose the attire of a religious divine. to probe into a restless mind never at peace with itself or the world around it. yet people were fascinated by his rare gifts and scintillating min~. and a merciless scorn for the mediocre. and its victims eventually included the Samanian rulers of Bukhara under whom Avicenna. in a long robe with a short jacket and a turban of coarse cloth. 59. Hence the difficulty of uncovering the complexities of a character composed of deep and varied strains. none uttering a word. He loved and sought company. he gave his famous reply that he wanted his years in breadth and not in length. a Baihaqi: Tatimmat ••. and on top of his political activities and intellectual pursuits this proved extremelyexhausting. . nor. his father. Never long in one place. one finds the tone of reticence both in the autobiographical account and the additions of his pupil more understandable. deliberately denying himself the pleasures of family life: he was a lonely man to his dying day.' We do not know how he dressed in his home town. From everyone he demands both quick wits and application. Yet he never married. Cf. 'He used to sit very close to the Amir. who says. When reproached for such intensive living. and assures us that he himself always went I Siiisat Niimeh of Nizam al-Mulk. And we have in support the evidence of Shahristani that throughout his life Avicenna was suspected of Isma'ili leanings. .attest to Avicenna's strikingly good looks and impressive figure. His disputes with fellowphilosophers reveal a violent temper. He does not seem to have had many close friends. Ni~ and Baihaql. whose face became radiant with delight as he marvelled at his good looks. It is in this connection that his pupil chooses to tell something that was repeated by all later authors I -not without malice. that we find the pattern of his life so uneven from the very start-sometimes even tragically tortuous. and he possessed an infectious joie de vivre that delighted his companions. he ventured into the bazaar. amend his own character.
which were shocking to Arab purists. some are spurious. he says: 'How I wish I could know who I am. In particular he is too repetitive. He is at his best in discursive rather than in assertive passages. as is sometimes supposed. To these may be added his behaviour in public and his utter disdain of conformity. if ever. and of these the most important have fortunately survived. by the testimony even of his detractors. they are the direct result of his knowledge of Persian. only fragments of it having survived. and which 78 he deliberately called Kitah al-Ifl!af (The Book of Equitable Judgement). and Book of Deliverance (Najat) helped neither to heal nor to deliver him. The authentic writings run to about a hundred. was lost in the sack of Isfahan. another was that his many writings ran directly counter to religious dogma. wealth. others are sections of some major work appearing under a different title. with which he must have been quite familiar. When compared to good classicalArabic prose. Often they half-mockingly remark that he was the person who died of sexual excesses.ich were very reluctantly. which has an easy way of forming 79 . and wh. they would have cracked and come crashing to the ground. These terms were derived neither from Greek nor from Syriac. and the quiet comfort of a home he confesses he never had. Often he lived under a cloud of menace. Most of what he wrote was in Arabic. The aphorisms give place to real philosophical argumentation. used by Arab authors after him. Most of the books that mention him are full of praise for his knowledge and ability.AVICENNA LIFE AND WORKS OF A VICENNA over what he WI'Ote carefully. Of what else could they accuse him? Power. This helps to determine the development of his thought to some extent. his sentences lack the compactness so characteristic of that literature. with a few works in Persian. The books of Avicenna suffer from being often ceuvres d' occasions addressed to a friend or patron and suited to his tastes and attainments. Avicenna's Arabic is definitely more lucid than that of Kindi and Farabi. so that but for the devoted efforts of his pupil they would long since have been lost. particularly where he tries to be 'expansive' as in the Shifa. These Persianisms can be detected in both the structure of the sentences and in his vocabulary. but actually this man of genius keeps the secrets of his true personality and leaves us still guessing. and such trials and troubles came rushing upon me. he never sought. and in spite of great self-confidence he claims that 'events befell me. he never gained. This obvious iII-feelinghad various sources. however. supposed to contain the results of his mature thought. One was his Isma'ili origin which was never forgotten. It was probably for that reason that he did not always trouble himself to retain copies of them. if authentic. that had they befallen the mighty mountains. but contain not a single kind word for the man himself. and as he was not a true Arab. and whose Book of Healing (Shifa).' These sidelights may stimulate our desire to know more about him. It is to be regretted that his last detailed work. his writings abound in what may be called Persianisms.' * * * * Of the two hundred books or more attributed to Avicenna. What it is in this world that I seek. we have a general idea of the order and sequence of his writings. some serious defects of style. Yet he rendered a great service to the development of philosophical style and terminology.' In a Persian quatrain which. His vocabulary is full of new abstract terms. must be considered a revealing cri de cceur. except for a brief troubled period. But the account is not always clear nor sufficiently instructive. He has. and sometimes they are even unidiomatic. written with the intention of arbitrating between the conflicting views of contemporary philosophers. Thanks to Avicenna's pupil. 'even though that is a very tedious task. In neither does he show felicity of language or interest in what might be called the magic of words (and of course the same could be said of Aristotle).
it is linguistically one of the most important books in the history of Persian prose. 'Ala' el-Dowleh. Only in A vicenna do we find a special treatise! devoted solely to definitions and the specification of terms. Although there is nothing new in the Diinish-Nameh that is not to be found in his Arabic writings. and they constitute a far more valuable contribution than any made either by Kindi. It stands to his credit that they continue to do so to the present day. no mention or trace of it remains. His Diinish-Namek is the first book on philosophy. and it is only since his day that most of the technical terms of logic and philosophy have acquired specific senses and values. Juzjani only tells us that it was written at the request of his patron. Classification was once considered a device of the Western mind. most of them can and should be used today. or by Farabi. This was a valuable service. but theirs had taken the form of aphorisms. He divides and subdivides far more than any Greek author. Hence the reason why his own countrymen found them natural and even felicitous. as well as the Falasifo who followed. Whilst Avicenna helped to establish Arabic philosophical terminology for a thousand years. Arabic philosophical language was not easy to mould. Still another contribution of A vicenna in this field is his attempt to introduce more precision in the use of Arabic terms. and even then the result was not always satisfactory. Although some of them sound rather archaic after the lapse of so many years. Arabic. There had already been tentative efforts' in that direction by Kindi and Farabi.AVICENNA LIFE AND WORKS OF AVICENNA them. Kindi and Farabi followed one set of translators consistently. Of these perhaps the most intractable was the total absence of the copula in Arabic. A characteristic of the Indo-European languages. I Risiilatal-Qudiitl. with the result that they had no choice of terms. and himself introduced into it abstractions never before used. and the natural sciences in post-Islamic Persian. Another feature of Avicenna's style--characteristic of his writings and of his mode of thought-is his passion for classification. had some formidable obstacles to overcome. while A vicenna had the good sense to compare alternative translations and choose such technical terms as he considered the best for his purposes. as has already been noted. It is difficult to say what motives inspired Avicenna to undertake this work. Thus it was sometimes necessary to use almost a dozen different equivalents in different contexts in order to convey an idea. who was his close companion and as a Christian physician trained in Baghdad certainly knew Syriac and may also have known some Greek. The early translators. But in the Shift he makes various illuminating remarks about Greek linguistics and grammar which can only be explained by the supposition that he was in contact with someone who had a fair knowledge of that language: the most likely person is Abu Sahl al-Masihi. logic. coined from pure Persian roots. and it is from him that mediaeval European philosophers copied that method. Avicenna's choice of terminology is also more extensive than that of his predecessors. There is no question of his having known Greek. It abounds in the most resourceful and happy equivalents for Arabic terms. while the Arabs considered them barbarisms. Aristotelian logic is so bound up with Greek grammar that it is sometimes doubted if it can be faithfully rendered into any other tongue. Nevertheless these neologisms helped to enrich Arabic philosophical language. who could make no sense of it because it was beyond his understanding. Reference has already been made to the fact that his initiative was 81 80 . Consequently his language is more varied and interesting. it does not exist in the Semitic tongues. he can claim to be the actual originator of Persian philosophical language. and this he never claimed. and the innovation places A vicenna in line with all the other bilingual poets and prose-writers of the Persian Renaissance. was the proper medium for theology and philosophy. It is highly doubtful whether any such work had ever been attempted before: if so. here we find it even more marked. the pure Arab.
Aristotle himself was not clear on the point. Both views are reflected in the conception of the Islamic philosophers. was seized upon with great enthusiasm and led them into fields as yet unexplored. It is clear that he used the medium of verse without any artistic pretensions. but they cannot be considered of great literary value.Who wrote philosophy in verse). but on the whole his claim to eminence cannot be extended to the field of poetry. but not regarded as being of any great importance. Avicenna wrote some poetry also. They were therefore principally occupied with the use of logic in their reasoning. The deductive method of reasoning from general premisses which had now reached them. and political exigencies militated against the development of this literary movement. Neo-Platonic and 83 . and it is after him that the logical works of Aristotle became known as the Organon. and we find very few subsequent authors wishing. and the practice has continued since in all theological seminaries. His Arabic poems. and were introduced into the collection of 'Umar by anthologists. was the first to call it an organon (instrument) of the sciences. The Stoics . It is quite conceivable that in his moments of loneliness-and they must have been frequent-he should have taken to verse in his own mother-tongue. and had been inclined to consider logic as a creative art (techne). to continue the effort. including the celebrated ode on the soul. The Islamic philosophers became acquainted almost simultaneously with the Arabic renderings of the Aristotelian Organon and various commentaries by Peripatetic. It has been thought that some of the famous quatrains of 'Umar Khayyam are really his. and what is its relation to philosophy? This had become the subject of some dispute among the Greeks of the post-classical period. has been a difficult question to determine. and did not worry overmuch about how to classify it. And yet religious. while the Peripatetics maintained that it was merely an instrument of thought. Ghazali and Tiisi. The Persian verses that have been attributed to him are of far greater merit.) AVICENNA copied by his younger contemporary. .after him contended that logic was actually a part of philosophy. and the same may be said of his poem on medicine. he could not very well classify it as one of the theoretical or practical sciences. The Platonists. social. said that it was both a part of philosophy and an instrument of the sciences.' though some Christian and Muslim theologians took strong exception to it . who wrote a number of treatises in as pure a Persian as he could command on religious and philosophical subjects. This. and his poem on logic has nothing to recommend it (except to remind us of Empedocles and the early Greeks . preferred to use the Arabic terms. however. between the second and third century. The subject had been entirely new to them. CHAPTER III PROBLEMS OF LOGIC WHA T is the object of logic. and its methods and applications seemed almost revolutionary. are elevating in thought and in theme. taking a middle course. Nasir Khosrow. the Isma'ili poet and philosopher. or venturing. Alexander of Aphrodisias. writing not so long after A vicenna. It had focused their attention on Aristotle as 'the owner of logic.
the relation of the art of logic to the intelligence and the intelligibles is as the relation of the art of syntax to language and words. and that 'there is no contradiction between considering it a part of philosophy and an instrument of it. I as the equivalent of the Greek dialelctikeI and also. they poured ridicule on the choice of the word. and takes no part in the dispute. Cases are recorded where in their heated discussions with logicians.' and as 'the tool of the philosopher. he names it 'the science of the scales' (tara{u). only to find that even before him Ibn al-Muqaffa' had given it that same new sense in one of his literary works. Vol. to be first trained in the science of syntax. • Stoic. Vet. By the time of Alexander of Aphrodisias and Galen. for 'it is incumbent upon hi~ w~o desires to theorize in philosophical logic. I. In one place he says.'3 For Aristotle also logic was primarily a matter of right thinking and secondarily of correct speaking. 332. he speaks of the eight books which included the Poetica and the Rhetorica as the logicals (al-Man{iqiyyat). translates iina 'at al-jaJal. as has already been observed.I Farabi calls logic an art in his classification. They could not therefore avoid taking some part in the controversy. 42. even though linguistically it is perfectly justified. and ofsophistics.' 5 Avicenna's definitions are numerous and somewhat varied. therefore. It may be thought. s IhiJ. but only to mean dialectics. It has been contended that the credit must go to the Stoics. Vol. The Arabic term mantic] we find in the fragments of the translation of the M etaphysica being used more than once Later the Eisagoge of Porphyry was added to make them nine books. of whose works not all have survived. Avicenna is fully aware of the problem but avoids taking sides. loo4h25. and also in that short paraphrase of Aristotelian logic of which mention has already been made. p. Frag. and loo5b22. called the last of the Romans and the first of the Scholastics. among which is the art of reasoning. of logilci. and refers to logic as 'the instrumental science. 3 liMa •. while in Persian following the Epistles. Zirgall. that he was the man who chose the word that he supposed had never had that connotation in the Arabic language. 404. and is also spoken of as 'the scales of philosophy. at least in any of his published writings.. 987bP). and of dialectics. probably under Stoic influence. II. nor is it quite clear who it was that first gave it that sense. linguistic and philosophical. 'logic is ~at science in which may be seen the N~if (Metaph. was one of the early pre-Hunain translators.• . logic is classified as one of the four species of 'true philosophy' .' But having considered it a science in one place. and the subje~t. In the Epistles we find some reflection of the point at issue.z The rendering is that of Ustath who. and we know that the term already occurs in Chrysippus. • • Cf. 3. it is in current use in the form of the Greek logike. and to the truth •. who maintains that logic is both a science and an instrument of science. He thus follows Boethius. z Cicero employs it. of logic was never to the taste of the theologians whether Christian or Muslim.' which conforms to the Peripatetic conception. Arab purists never approved of this neologis~. Kindi's definition of logic has not come down to us in a clear form.'4 The logic of language. I 85 . p. and to lead man to the path of correct [thought]. He insists in the Shifa that the entire dispute is irrelevant. he calls it an art (#na'a) in another. There. Aristotle had never used the term logic in its modem sense. the linguistic is such as the art of syntax ••• and the logic of judgements is of different branches. p. 4 Edit... Metaph.AVICENNA PROBLEMS OF LOGIC Stoic authors who had raised the question of the use and purpose of logic.. The authors of the Epistles maintained that 'the sciences of logic are of two kinds. Kindi. Farabi says 'the art of logic gives in general the principles whose purpose it is to help the intelligence forward. they thought.' He adopts the term instrument (ala) which he knew came from Alexander. should be mastered before the logic of philosophy. seems silent on this matter. in some passages. more especially since they had taken upon themselves the task of justifying the whole subject and defending it against its detractors. 53.
s and all a priori attempts to equate Avicennian terms with those used by the Stoics are to be discouraged as dangerous.'! But by far the most conclusive evidence is in the field of terminology.s but it is difficult to say to what extent they were acquainted with their works.'2 In still another he remarks. 124. definitely determined. 'thus logic is a science from which is learnt the modes of passing from matters determined in the human thought. . for the purposes of the present inquiry it would be even more important to study the Arabic version. ~ Cf. 87.for which there are no equivalents in the translations of the Organon. it is far more likely that Stoic logic reached A vicenna not directly but by way of Peripatetic and Neo-Platonic commentators. and the varieties wherein it is otherwise. Lexicon of Logic. Fol. to matters to be determined. who made the categories four. 3. Paris. whose work on logic we know "J 3 !shiiriit. p." is not to be referred to with absolute synonymity. among them those . mimeographed edition. :11.' In fact throughout the Shifa he differentiates between what he calls 'the first teaching (al-ta'lim al-awwa/). 38. pp. and that which it is that is false." In another place he states that logic 'is for the intelligence a guarding instrument against error. we have the testimony of Ibn Taimiya that 'Avicenna and his followers dissented from the ancients in a number of their logical statements and in various other things. Nor would the effort prove fruitful unless the logic of the Commentators of Aristotle had first been carefully examined. Usaihi'a.'v which clearly points to the Stoics. 4 Kitiih al-Radd . and the different varieties of each.!. p.'3 The logic of Avicenna has not yet been properly studied. and Avicenna. it goes much farther in scope and subject-matter.' meaning the Aristotelian. and which correspond very well with such Stoic terms as have survived. No such study of the original Greek has yet been made. Nevertheless. 3. and they are those who are called and known as the men of the shaded place (~~ah al-maralla). and it is that which leads to true belief by giving the reasons and methods of arriving at it. p. One author makes mention of the 'fourth figure' in syllogisms+ which as has been shown5 was not introduced by Galen. Nevertheless. AVICENNA 1 PROBLEMS OF LOGIC state of knowing the unknown by the known. and where according to the Stoics (al-Rawaqiyyin).•. and later teachings. and to limit them to categories of fewer number. and Zeno the small. as he calls them. the correspondence is sometimes so close as to give some measure of certainty. through the various commentators of whom there were so. it remains to be seen whether such additions as are indisputably Stoic reached them directly or. in what we conceive and give assent to. and the number and varieties wherein the order and the form of the transposition lead to correctness. p. and they are the spirituals. 86 . but by some unknown logician after the fifth century. and their originality. many in the Hellenistic age. Although our knowledge of Stoic logic is very Iimited. 22. 5 Lukasiewicz: Aristotle's Syllogistic. 1. p. The vocabulary of Avicenna abounds in logical terms.' 4 The Islamic Falasifo did know of Zeno and Chrysippus and also Diogenes. and significantly adds that 'philosophy. 4 3 S Shifii. well aware of the Stoic attempt to reduce the Aristotelian categories. Qazwini: Al-Risiilat al-Shamsiyya. Farabi has frequent references to Zeno the great. Vol. 9. Cf. ~ Najiit. J who took pains to make some of these enter into others. Furthermore. and that which it is that is near the truth. MS. but there were Peripatetic and NeoPlatonic influences as well. Many have suspected that the additions are derived from Stoic sources. . and the state of these matters. 209 • 6 Qifp. p. 36. Among these were Galen. Mates: Stoic Logic. that which it is that is in truth. In one source-book "there is mention of 'a group who are associated with the science" of Aristotle. for only then could the contributions of Avicenna be placed in their historical setting. Even the most superficial acquaintance with Islamic logic reveals the fact that although Aristotelian in general outline. p. if any. speaks of 'those DiInish-Niimeh. where it is according to the Peripatetics (al-Mashsha'in).
this particular amalgam of the two which developed in the late Hellenistic age influenced them greatly. This was considered a necessary introduction to logic and some supposed it actually a part of the Organon. they differ somewhat in form and in content. Simplification was desirable for one whose conception of the subject was practical: logic.expressed his own mature views towards the end of his life.' 'We do not worry. and in the fragment called Man{iq al-Mashriqiyyin (Logic of the Orientals). simplifies the matter almost out of all recognition. But towards the close of the Greek period in the history of logic. A vicenna does not go as far as Russell in dismissing all the Aristotelian categories. for whom Avicenna expresses much appreciation and who in his refutation of the Stoics had discussed much of their logic. Lukasiewicz was among the first to demonstrate that whereas the Aristotelian was a logic of classes. as a tool for correct thinking. besides the works of Aristotle. which was entitled al-lfikmat al-Mashriqiyya (The Philosophy of the Orientals) and in which he had . the noted disciple ofProclus and the author of various commentaries on Aristotelian logic. we do not worry I Cf. p. and on the other hand he asserts in his Physics that we need not necessarily postulate only ten genera of being. was to be made sharp and effective. Avicenna. It should not be supposed that the deviation is very marked. Avicenna had discussed logic in some fifteen different works. and may have had a translation of the Stoic works. Ammonius. mistakenly translated by the Latins as Sufficientia. Alexander. and while the Arabs had the whole of the Organon before them.. that Avicenna must have derived most of his knowledge of Greek logic. In the case of the hypothetical syllogism. z. ignoring the original sources. to modify and to augment without the least hesitation. with a good measure of simplification and perfecting on his part. In later books such as al-Ishdriit wa al-Tanbihd» (The Directives and Remarks). J'Histoire ••• du Moyen Age • Mantiq. 'to show a departure •. but there is certainly an attempt to think over the problems independently. With this in mind it may be claimed that the logic of Avicenna really combines the two. Porphyry. as Alexander and John Philoponus testify. the two had already merged.'> This attitude is best expressed in what is supposed to be his last work on logic. but via a critical assessment of the two doctrines. but he does not mind stating that at least one of them means nothing to him. was first discussed by Theophrastus and Eudemus and later developed by the Stoics. commonly calJed the Grammarian. to discard. It is from these. In point of fact a distinctive feature of Avicenna's entire philosophy is that he shows himself perfectly ready to accept. he may be considered more Aristotelian in approach and to some extent in subject-matter. the Stoic was one of propositions. including one of motion. which. Pi~es:La Philosophie orientale ••• Arch. In the Shift..AVICENNA PROBLEMS OF LOGIC to have been translated into Arabic and widely read. It is contended that he called it 'Oriental' so 'as to contrast it with the servile Aristotelianism of some Christian philosophers in Baghdad who were to him 'Occidentals.' as meaningless. 'That we may put down some statements on what men of investigation have disagreed upon •. and finally John Philoponus of Alexandria. he is inclined to deviate from Aristotle. as well as in the abridged version called Najat (Deliverance). 1953· 89 .' he says. but judging from what has survived. from those philosophers enamoured of the Peripatetics who imagine that God did not guide any except themselves. whose commentary was almost a textbook in its Arabic rendering and was sometimes called by its Greek name of Eisagoge (Introduction) or by the Arabic equivalent of al-Madkhal. for other 88 categories may be added. both title and contents have been interpreted in various ways. and even the word 'category. The latest and the most plausible theory is that it formed part of a much larger books which we know Avicenna had written. The Logic of the Orientals has become the subject of much controversy. in his Persian Danish-Nameh (Book of Knowledge). not by a mechanical superimposition of one on the other.
and every belief comes by way of a syllogism. it became easy for us to comprehend what they said. and it may be presumed. A vicenna..•. 6 Mnan. 51. Frag. thing) and Stoic AeKl'O'P (abstraction: what is capable of being spoken). . either out of oversight or lack of understanding . I mean for those who take the same position as ourselves... it is in things in which we can no more show patience .6 But the Stoics. ~ 'Uyiin al-Masa'il. such as our conception of the quiddity of man. and because those who occupy themselves with science are extremely proud of the Peripatetics . op. . 56. starts from particulars.. All knowledge. certain sciences may have reached us. . when we first took up that subject. Having defined logic.4 Mantiq. altered the terms and developed the thought. In any case the vague and fragmentary parts that have reached us of this work hardly fulfil the promise that he gives.. cit. that it was through some commentator that it reached Avicenna. we then compared all these with that variety of science which the Greeks call logic-and it is not improbable that it may have a different name among the Orientals •. And it is not improbable that certain sciences may have reached us from elsewhere than the side of the Greeks •. what is even too much for them and beyond their requirements. and it could be I through the imaginative faculty. 1943. . It may be observed that he regards concepts and assents as the primary sources and correlates them with what he takes to be the fundamentals of logic. though there is no direct evidence.4 They could just as well be attributed to Chrysippus. begins with a brief discussion of the theory of knowledge.'3 Some have tried to attribute them to Sextus Empiricus. Thus definition and syllogism are twin tools with which are acquired the knowledgeables that are known and which through thought become known. they consider that looking deep into matters is a heresy. What is the source other than the Greek from which. and if we venture to oppose them. Vet. and that opposing what is widely accepted is a departure from the right path •.AVICENNA PROBLEMS OF LOGIC about any departure that may appear on our part from what the expounders of the books of the Greeks have been occupied with. 59. 3. definition and syllogism. 55.w The origin of these two terms and their Greek equivalents in particular have 'baffled modem scholarship for over a century. 5 Stoic. we gave them in the book of the Shift. . Again he says that all knowledge is either the concept of some particular notion that has meaning (ma'na)8 or an assent to it. 7 After Avicenna it becomes the introductory statement of almost every manual on logic whether in Arabic or Persian. viz. according to Aristotle. can be traced back to Arabic translations of the Organon. and the concept is the first knowledge and is acquired through definition and what follows the same method. he says. I . For Farabi 'the knowledge of a thing could be through the rational faculty. 2-4. . we disliked to dissent from and oppose the public .• . and what is the name the Orientals gave to logic different from that of the Greeks? Is he referring to Indian thought. 3 Wolfson: Moslem World. . and we did not compile this book except for ourselves. with their well-known interest in language. II. Among the Faliisifo· it is first found in Farabi. And assent is acquired through syllogism and what follows the same method. p. But there are matters to which we give our assent . • Najat. 8 Aristotelian 'PoIjpa (JewP1'Jlla (what is perceived). And as to the common people who engage in such things. or Middle Persian writings.5 Actually the terms of A vicenna and to some extent the concept. and all assents and concepts are either acquired as a result of some investigation or they are a priori. like the Stoics. There could be a concept without an assent.. p. and it could be through the senses. or what had developed in his own part of the world? In spite of innumerable theories. Ihid. such as our assent that for everything there is a beginning. and we overlooked what they were struggling with . no satisfactory answer has yet been found. but in a highly suspect treatise which may be actually by his successor." This passage is provocative. pp.'! For Avicenna 'all knowledge and cognition is either a concept (tcqawwur) or an assent (tcqdiq). Madinat •. 1TpaYlla (deed.
43. Frag. to which the evidence of everybody •. causes assent." Moreover the current practice has been to call what leads to the required concept an expository discourse (qawlun shiiriM. p. A vicenna says that every predicate may be either constitutive or concomitant or accidental. but 'to imagine something to be something else.. The vocable could also be particular or universal. differentia. in which a vocable signifies the meaning for which it stands. • Cf. property and accident. descriptions and similar statements are of this kind. pp. though some scholars have held to it tenaciously. 62.~. did Greek logic have any influence on the development of Arabic grammar. and yet another is by way of concomitance (iltqam). and the problem thus arises.s probably under St~ic I 3 1>(1)vi}. One is by way of complete accord (mu{abaqa) between the two.' and empirical data (mujarrabat) 'which are matters to which the sense in association with syllogistic reasoning causes assent. Stoic.' And there are a priori data (awwalfr. though there occurs a curious classification into six: genus.' And there are presumed data (marniinat). famous and praiseworthy. and accident. with differentia as a subdivision.I The vocable could be singular (mufrad) or composite. differentia. but before taking up that subject he realizes the necessity of specifying the terms and determining their meaning. pp. II. 'losing sight of the principle on which the division was made. 262.\E. and this division of the predicables had been accepted by some logicians of Baghdad. There are three ways. this is either because of a heavenly injunction in his favour.1. genus. or because of an opinion and effective thought by which he has distinguished himself: And there are imagined data (wahmry-yat) 'which are opinions in which the faculty of the imagination necessitates a belief.1>aUl~. syllogism. This was for him an unusual departure from Aristotle which proved rather confusing to his successors who had thought of him as a faithful interpreter of the Stagirite. It may be noted that some of the terms used here are shared by Arabic grammar. p.• or of the majority or the evidence of the learned or of most of them. individual.rat) 'which are premisses and propositions originating in man by way of his intellectual faculty without any cause except its self to necessitate its assent. species. to Logic. Aristotle had discussed the predicables in the Topica and had there specified that they were definition. 3 /sharat. I. and proofs are of three varieties. 60 if. induction and analogy. which was systematized and established rather late in the history of the language? This is a moot question on which opinion is divided. and accident. • Cf.AVICENNA PROBLEMS OF LOGIC without the intermediary of syllogistic reasoning. and every universal could be essential or accidental. The Eisagoge had been translated into Arabic.' And there are transmitted data (mutuwatirat) 'which are matters to which the transmission of news causes assent: And there are the accepted data (maqbuliit) 'which are matters to which the word of the person in whose truthfulness there is confidence causes assent. Vol. thus making them five in all. There are sense data (ma!zsilsat) 'which are matters to which the sense causes assent. Risalat al-Jami'a. property.' And there are generally widespread data (dha'i'at) 'which are propositions and opinions. Avicenna pays much attention throughout to definition. 93 . Porphyry in his Eisagoge. and the composite (muralclcab) may be a complete or an incomplete discourse.'> replaced definition by species and maintained that the predicables were genus. Vet. because there is a certain relation between the vocable (laA)3 and its connotation. Joseph: An Introd. he points out. Najat. though he eventually lost that position after the bitter attacks of Avicenna and his scornful reference to his works. and states affectI ing the vocables may also affect what they designate. On predication. And there are imaginative data (mukhayyalat) which are propositions not stated to obtain assent of any kind. species. another is by way of implication (tar/ammun). . and to call what leads to the required assent a proof. 4. and considers it of fundamental importance. In our view there is very little evidence in favour of this theory. property. definitions.
AVICENNA
PROBLEMS
OF LOGIC
influence. A vicenna accepts the five predicables, but not Porphyry's definition in every case. 'Do not pay any attention,' he says, 'to what the author of the Eisagoge has to say on the descriptive definition of the genus by the species.' Avicenna is opposed to this because he himself distinguishes between natural genus and logical genus. Natural genus is equivalent to the actual essence of a thing in answer to the question 'What is it?,' such as animality; logical genttS on the other hand is what is added to natural genus in order to give it universality, for logic is a subject that treats of universals. And in this connection he dubs Porphyry 'the master of bluff and misrepresentation,' whereas Alexander he had called 'the accomplished of the latter ones,' and Themistius, 'he who polished his phrases on the books of the first teacher [i.e. Aristotle].' Modem logicians share Avicenna's view on this point and take exception to Porphyry's definition of the genus. Again Porphyry had divided accident into separable and inseparable,r which modem logicians consider impermissible, because 'if a singular term be the subject, it is confused; if a general, self-contradictory';" and Avicenna says 'do not worry that [an accident] be inseparable (mulii{im) or separable (mufariq).'3 He then proceeds on his descriptive definitions. 'A genus may be descriptively defined as a universal predicated of things of different essences in answer to the question "what is it?" '4 'A differentia may be descriptively defined as a universal predicated of a thing in answer to the question "which thing is it?" in its substance. And species may be descriptively defined in either of two meanings: first as a universal predicated of things that do not differ except in number in answer to the question "what is it?" and . . . in the second meaning as a universal to which, as to others, the genus is given as predicate, an essential and primary predication. And property may be descriptively defined as a universal predicated of what is, under one essence only, an attribute that is not essential. And the general accident may
I
XWptcn6v-O.x
3
Najiit, p.
wpurrov.
94
• Joseph: op. cit., p.
4
be descriptively defined as a universal predicated of what is under one essence, and also of others, an attribute that is not essential." Just as Aristotelian metaphysics was to become sadly confused with Neo-Platonic thought through the translation of the socalled Theology of Aristotle, to the utter confusion of Islamic philosophers, so here we find Aristotelian logic becoming intermingled with that of his followers and also with Stoic logic either directly or through the perplexing disquisitions of the commentators. Galen, whose extant Instuutio Logica has been vehemently denounced as spurious and equally vehemently proclaimed authentic, was among those who transmitted this combination. As to Chrysippus, of whom it was said 'if gods have logic, this must be Chrysippian,' there is no sufficient evidence that the Faliisifo, and Avicenna in particular, had direct knowledge of his work. With regard to definition, which Avicenna discusses in a number of places and at great length, he states that it is not something that can be obtained through division, which we know to have been the method suggested by Plato. Nor is it possible to reach an adequate definition through demonstration; and even induction must be ruled out since it does not give conclusive knowledge and cannot therefore be of much help. Definition can only be attained through a combination of the above, based on the individuals (ashlcha~)" that are indivisible. In attempting a definition, philosophers do not seek differentiation even though that may follow. What they seek is the reality of a thing and its essence. For this reason there is really no definition for what has no existence: there could only be a statement explaining the name. Where definition is confined to the cause, it is called the principle of demonstration; and where it is confined to the caused or effect, it is then called the consequence of demonstration. The complete , definition combines these two together with the genus. Like Aristotle, A vicenna defines a definition as 'a phrase signifying
I
lOS.
10.
Cf. Top,
102a31.
!shiiriit, p. 16.
95
AVICENNA
PROBLEMS
OF LOGIC
the essence of a thing." And in Persian he repeats that the purpose of a definition is the recognition of the actual essence of that thing, and differentiation is something that follows by itself. It is to be remembered that the authors of the Epistles before him had stated that differentiation was an actual element and a part of every definition; and Averroes after him asserts that all definitions are composed of two natural parts, genus and differentia. From definition Avicenna turns his attention to the second source of knowledge which is assent, obtainable through syllogistic reasoning. But actually he continually reverts to the subject of definition,particularlydescriptive definition (rasm: a term used by the translators of the Organon as the equivalent of a number of Greek words used by Aristotlej.s A proposition he defines as 'every discourse in which there is a relation between two things in such manner that a true or false judgement follows.'3 It is known that the Stoics also considered a proposition to be either true or false;4 they believed that Aristotle held that propositions about future contingencies were neither true nor false. Avicenna adds that 'as with interrogation, supplication, expectation, request, surprise and the like, the person who expresses them is not told that he is truthful or untruthful except accidentally.'5 Like the Stoics, Avicenna divides propositions into atomic and molecular; the latter being compounded out of the former by a conjunction or connective (ribat).6 The molecular is then divided into 'the categorical (al-~amtty),the hypothetical conjunctive (al shartiy al-muttasil') and the hypothetical disjunctive (al-shartiy al-munf~il)'-a classification which has its Stoic counterpart." The hypothetical proposition was already known to Aristotle''
I
Cf. Top., 101b37; /sharat, p. 17.
3
Najat, p,
12.
22.
4 d~tCJ)/la Trov ~'
• TVrr~, ~la'Ypa/l/lm;a, 'Ypa~CJ), (JTJ!llsla. ~i eUTwlJ EUTW dATJOk i}, 'l'eiJScx:.
TroY ~p.Evov
5 /sharat, p,
oVX a1TAroy d~ICJ)/la (JVP.1TB1TAeyp.ivov ~i ... ~IE'WY/livov M ... 8 EK VrrOOi(JEa¥;: (A. Pr. 50ilP) 'an sharita,
7 Amim, II, p. 68.
6 (JV'lI~E(JWJf:· /lev •
though he does not seem to have explored it. Theophrastus is supposed to have studied it, but only to a limited extent. It is therefore impossible to state with any certainty the source from which it reached Avicenna. The similarity of his approach to that of the Stoics, however, is very close; and like them he devotes much attention to it. Yet he does not stop there and goes on to discuss a number of other propositions such as the singular, the particular, the indefinite, the limited or quantified, the modal, the absolute, and various others for not all of which it is possible to find an equivalent in Aristotelian logic or those Stoic writings that have reached us. One proposition which he definitely claims to be his own, is what he calls 'the existential' (wujudiyya), and this he explains in detail in the Shift. J t arises from the fact that the copula does not exist in the Arabic language, and this was a complication of which A vicenna was well aware and to which he frequently refers. To remedy this linguistic obstacle, various equivalents had been used in different contexts, and among them was the verb 'to exist' (wajada). It was from this root and for this purpose that he formed his existential proposition. And Ibn Tumlus testifies to that and explains that it was called existential because it signifies existence without having anything in common with the idea of necessity or contingence. A vicenna, of course, was not the source of Boethius who centuries earlier had discussed these matters in his De Syllogismis Categoricis and De Syllogismis Hypotheticis.1 These works which had an undoubted influence on mediaevallogic stem from Nee-Platonic and Stoic writings which Boethius had imbibed in Rome. A review of the conditional proposition leads to the theory of consequence, a notion which, as the fundamental conception of formal logic, played an important role in all Arabic and Persian as well as Western mediaeval systems, and continues to occupy contemporary logicians,s Whether the doctrine can or cannot be traced farther back than the Stoic and Megarian school, as
I Cf. Durr: The Propositional Logic of Boethlus, • Cf. Camap: Logical Syntax, p. 168.
96
D
97
AVICENNA
PROBLEMS
OF LOGIC
described by Sextus Empiricus and Diogenes Laertius, it is the case that the Arabic terms for antecedent (muqaddam) and consequence (tali) are not to be found in the translation of the Organon, and must therefore have entered the language through some other source. This could have been through Stoic writings directly, in which we find the Greek equivalents,' or through the works of some of the commentators of Aristotle. It is in Avicenna that the terms are first defined, and successors like Suhrawardi and Ibn Tumlus only copy him. He states that just as the categorical has two parts, a subject and a predicate, the conditional also has two parts. In the hypothetical conjunctive proposition there are two and only two parts or clauses; one is the antecedent and the other the consequent. The antecedent is that to which the condition is bound, and the consequent is that which constitutes the answer. In the disjunctive, however, there could be one or many consequents to the antecedent. So that the difference between antecedent and consequent and subject and predicate is that subject and predicate could be replaced by a simple term, whereas antecedent and consequent could not because each is in itself a proposition. Another set of terms for which there are no Aristotelian equivalents, and which must have therefore entered Arabic from some other-probably Stoic-source, are those used for a conclusive (muntij) and an inconclusive ('aqim) proposition. But in his definition of a thing (pragma) which so occupied the Stoics and led to so much discussion, Avicenna follows 'the owner of logic,' as stated in the De Interpretatione. 'A thing (shai') is either an existing entity; or a form derived from it existing in the imagination or in the mind • • • or a sound signifying the form ..• or a writing signifying the sound.•• .'Z These examplesgo to show that Avicenna is no servile imitator of any school, but thinks over every question independently and with an open mind. Another illustration of this attitude occurs in connection with his examination of absolute propositions.
I
'There are two views with regard to the absolute [proposition],' he says, 'the view of Theophrastus and Themistius and others; and that of Alexander and a number of the accomplished ones.' And after giving their viewpoint, he adds what he supposes may have been the original conception of Aristotle himself. And he finally concludes with the remark that 'we do not occupy ourselves with showing preference for either the Themistian or the Alexandrian viewpoint; we would rather consider judgements concerning the absolute in both manners.'! There are three procedures for proving something. One is syllogism (q!yas), the second is induction (istiqra') and what accompanies it, and the third is analogy (tamthil) and what accompanies it.Z In agreement with Aristotle in the Analytica Priora, Avicenna says, 'a syllogism is a statement composed of statements from which, when made, another different statement by itself and not by accident, follows necessarily'; and syllogisms are perfect or imperfect. It is in his division of the kinds of syllogism that he differs from Aristotle. In all his works without exception (and therefore it could not be a late development in his system), he says that syllogisms are of two kinds, the iqtiriiniy (by combination, by coupling) and the istithna'iy (by exclusion, exceptive); and in one passage he claims that this division is 'according to what we verified ourselves.'3The origin of this division, if indeed it has any outside Avicenna's own mind, is not known. (Aristotle in the Topica had divided syllogisms into the demonstrative, the dialectical, and the sophistic. Galen divides'syllogisms into the hypothetical, the categorical and the relative.j+ It may well be a case of Avicennian simplification; but the terms that he has employed are difficult to translate correctly. The attempt of a modem author to equate them with the categorical and the hypothetical is not satisfactory. They are definitelynot of Aristotelian origin. The term iqtiriin does indeed . occur in an Arabic translation of a fragment by Themistius
I
TO 1j),OOJ.'EVOV--TO ,\1jyov.
• Najat, p.
II.
3
Najat, p. Z3. Ihid., p. 65.
4 woOenKol,
• Islzarat, p, 64. KaT1])'OptKOl, KaTcl TO 1Tpck TI.
98
99
This is of Stoic origin and is a literal translation of the Greek ov'vyla (yo. 4hu). Tiisi. But the fact that it had been introduced into Islamic logic through some external source -possibly Galen-is shown by its use in Qazwinl. and we find them used by A vicenna also as muqaddima (premiss) and natija (conclusionj.uoylCeaOat (Soph. was a statement composed of premisses and a conclusion. 62. 19bu) maqriin. and all throughout his logical works we have not seen A vicenna make any mention of the fourth figure.48. Epistles. U3a12) h:diwaj. E1Ttif>opd. 63. avp1Tepaapa 101 Shija. p.1 And again 'the istithna'iy syllogism is different from the iqtirciniy in that one of the two extremes of what is wan~ed (matlrlb). Pro 28a14) al-wad'. Asas . With their zeal for linguistic innovation. Farabi had said that 'the truth of a thing. according to the Stoics. p. . Lukasiewicz.AVICENNA PROBLEMS OF LOGIC without any explanation.' A vicenna stated that 'the truth of a thing is that particularity of its existence which is proven of it' . (al-mustathnat)'.~ is fo~nd in the istithna'iy syllogism actually. 5 To d}.5 and the same distinction is found in Avicenna who calls the first fadiq and the second fidq. and it could possibly be categorical or hypothetical. p. 1229 Cf. which corresponds with the Stoic doctrine that it was a simple and incorporeal notion (lekton). howeyer. • CTJTovpevov.. 3 100 . 166. then there necessarily follows from them another proposition which is composed of those two terms which were not in common between them . 8 Bea" (Categ. "every body is formed. or from the two combined. . however. He mentions as many as thirteen. edit.'3 What is to be resolved is the origin of the name. 169b29) qarana iqtiranan. p. aVYKeiaOat (P.s The word as used by Aristotle in the Organon had been translated into Arabic as qdiwaj. Fol.. von Amim.6 and on the Stoic side by some fragments that have survived. and 1~ not found In the zqtiraniy syllogism except potentially. p. wad'.. p. p. I.1JB~. Asiis •. 5 4 6 Najat. we are told. 279. one conditional and the otherwith an ecthesis (wa4')8 or exclusion (raf') of either of the two parts. Tahanawi. they had changed the terms of Aristotle into those of their own. 4 Cf. .7 The istithna'iy (by exclusion) syllogism is more difficult to identify by association with any particular Aristotelian or Stoic term." and "everything that is formed is created.. He explains that it 'is composed of two' premises. and Suhrawardi. . and also in Tiisi. 3 Isharat." '2 All this is simple. Ghazali says 'the categorical syllogism is sometimes called the iqtiriiniy syllogism and sometimes the ostensive. p. On the other hand the Arab iqtiran had been used by the translators to render other Aristotelian terms in the Sophistics and the De [nterpretatione. av. This corresponds with his differentiation between ~aqq and ~aqiqa which go back to Aristotle himself and are to be found in the translations of his Organon. adds that 'truth is a mental consideration'. p. II." hence it necessarily follows that "every body 'is created. avCvyla (Top.'! but he seems confused himself. Stoic Aijppa. Paris. II. after repeating the definition of Avicenna. and it is this which is called the excluded I Mi 'yar •. as we have already noted.s The equivalence of the Avicennian iqtircin with the Stoic ov'vyla becomes evident from the statement of various authors before and after him. having one term in common and the other different. ~ aAA6eta. 50. Zirgali. I 6 7 • Danish-Nameh. 160.. 186. distinguished between 'true' and 'the truth'. is the exis-· tence particular to that thing.ke) which had a vague and general sense in Aristotle. Herm. Peripatetic 1TpOTaa".. and it is difficult to determine whether the varieties were his own or taken from some other source. 337.'3 Anstotle had divided the syllogistic modes into three figures. but the Arabic equivalents of both the Aristotelian and Stoic remained the same. 77.s It is. in his enumeration of the different varieties of premisses that we find him going beyond anything said by Aristotle.. A vicenna states in Persian that 'an iqtirciniy syllogism is that in which two premisses are brought together. and in Arabic he adds that 'iqtirciniy syllogisms could be formed from pure categoricals. EKfJea" (A. MS. An argument.4 The Stoics. 66. or from pure hypotheticals. but which became a technical term with the Stoics.
17. which denotes neither permanence of existence nor of non-existence. He even coins Persian abstract terms for these concepts. In Avicenna it is discussed at length and all his successors follow him in stressing that there are two forms. 2sal. But even before arriving at that. devotes more attention to it. specifying at the same time. a Tahanawi. p. The confusion is only due to terminology. that it had a twofold connotation comprising possibility and contingency. There is a passing mention of it in the Epistles.1 and a lexicographer explains that 'a proposition that comprises the silr is called quantified (musawwara) and limited (maMiira) and it is either general or particular. Considering that this doctrine had already a long history in the post-classical period. which is the pivot of his entire philosophy. . Herm. In any case we find Avicenna saying 'the modalities (jihat) are three. al-mumlrin. 103 .. before it was invented anew by Hamilton and Jevons. contrary to what some have supposed. who is said to have been the first to use the term tropos in that sense. a 4 Danish-Niimeh. This might suggest that unlike Aristotle. It is generally thought that this problem first appears in the Prior Analytics. and in close correspondence with the Sophistics of Aristotle. even though he is inclined to consider it a fallacy. the possible. however. The Aristotelian term for contingency has been translated differently in different passages. Pri. Kindi uses the term rather vaguely. p. Najiit. in Persians and at much greater length and clarity in Arabic. 2Ia3S). :ua)4-37. which denotes permanence of non-existence. An. the authors of the Epistles have more to say on the subject and distinguish two forms of predication: the general and the particular. p. 2Ia3S). Avicenna. 14. the impossible and the necessary. In fact the notions of possibility and contingency are of fundamental importance to him. it is interesting to speculate on the sources from which it entered Arabic and Persian logic. the contingent. impossible.s This is confirmed in the commentary of Ammonius.u This division into three rather than four is copied by his successors as far away as Andalusia. Najiit. Modern scholars have argued with some justice that actually the contingent and the possible are practically indistinguishable in Aristotle. though it does not appear in any of the works so far published. Pri. 6S8. P. p. p. Pro 32aI9). viz. mumkin. is in its very nature not susceptible of falsehood. TO blJexopEV01I (P. S TO lJeov (Sopk. 3 Najiit. Philo had defined the necessary as 'that which being true.AVICENNA PROBLEMS OF LOGIC The doctrine of the Quantification of the Predicate is not of Aristotelian origin. who had no access to the original Greek. 101. Herm. necessary. and possible. and may therefore have come to him by way of some commentary and not from the Aristotelian texts direct. and the Arabic term silr standing for quantification is not to be found in the translations of the Organon.'3 hardly differs from that of Aristorle.v Aristotle's distinctions of modality are four.s But in his lengthy explanations he contrasts the ordinary and the special senses of the term mumkin and he distinguishes between what is binding (wajib)5 and what is necessary (r. like all and not one and some and not all'. Herm. A vicenna does not differentiate between the possible and the contingent. 17. P: 2S· A. 16Sb3S) wiijih. and that in the opinion of some modern logicians there can be no truth in it. which denotes permanence of existence. it may be presumed that Farabi too dealt with it.' A vicenna. seems to have preferred the term mumkin for both notions. he takes up the problem of the Petitio Principii (al-mUfadara 'ala al-marliib al-awwal).' Avicenna ends his logical treatises in the traditional way with a discussion of the different fallacies (mughalitat). but in fact he does differentiate between the I I I' I two notions.. 32a19. 44. His definition of the contingent as 'that judgement which in the negative or the affirmative is not necessary. and extend far beyond logic to the field of metaphysics. Avicenna says 'silr is the term which signifies the quantity of limitation. In the Shifo he speaks of I TO mwar01l (P. muktamal: TO blJexopEV01I (A. 3 Najiit. 4 I. but the Arabic terms as used by A vicenna are slightly different from those of the actual translations.farilri).
or Ibn Tumliis with his avowed preference for Farabi.. Stoic. in his discriminating acceptance of some of the later additions and modifications. The question whether Avicenna was a nominalist or realist is not easy to resolve. the mystic author of the 'illuminative' philosophy. In the writings of his successors and certain lexicographers. he refers to the matter with an explanation and without specifying whether it is a correct method of reasoning. The Aristotelian Organon with its sometimes conflicting accretions in the form of treatises of Hellenistic origin had produced a hybrid mixture of extraordinary complexity and of diverse traditions.. it seems to be accepted as a valid way of reasoning. and his position not always very clear. but until more of his works come to light we are in no position to judge his full contribution. along the path that he had opened. The only person to challenge his philosophy effectively. 34. however. it is seen that they had hardly anything to add. But the measure of his success. and this conceptualism is the attitude of many modern logicians. One person who attempted alterations and the development of what he called a logic of his own was Suhrawardi. and attack his logic. and we find Albertus Magnus saying: 'Quae ex logicis doctrinis arabum in latinum transtulit Avendar israelita Philosophus et maxime de logica A vicennae. Furthermore he can claim the credit of having set the direction of development -if there was to be any-for those who were to follow. as far as logic was concerned. was directed against Greek logic in general. p. Nevertheless interest in the subject continued until it became an essential part of the curriculum in all seminaries. When the logical works of his successors are examined. . and finally in his critical reconstruction of a system which he considered valid and adequate. In the long vista of Arabic and Persian logic. The arguments of Ibn Taimiyya. and even try to change some of its terms.•. The line extends directly to mediaeval times. early authors tended to give the place of honour to Farabi. Kitiih al-Radd . is reflected in the disparaging remarks of Ibn Tumlus. 104 D* . Megarian.AVICENNA PROBLEMS OF LOGIC 'the petitio principii that is included among the genus [of those things] that it has not been possible to prove'. and that which is according to the essence is a detailed discourse making known the essence through its quiddity'j! thus he accepts the conceptions of both nominalism and realism. The genius of A vicenna consisted in his careful selection of the fundamental principles from what he called 'the first teaching'.• its subject was the secondary intelligible meanings (ma'iini) that are based on the primary intelligible meanings' . was Ghazali. while in the shorter works like the Najat. This is confirmed by his statement in the Shift that 'the logical science . and may therefore be considered a conceptualist. His influence dominates every single book on the subject in either of the two languages. such as Averroes with his sterile Aristotelianism. not with any notable results. and that which is according to the name is a detailed discourse signifying what is understood by the name for the person who uses it. Even among the Andalusian philosophers who were I highly critical of him. Peripatetic and Neo-Platonic. there is nothing worthy of note.' I cr. After him A vicenna stands supreme.• Mantiq . But he maintains that 'a definition is either according to the name or according to the essence.' one of the most able and accomplished theologians.
PROBLEMS
OF METAPHYSICS
CHAPTER
IV
PROBLEMS
OF METAPHYSICS
which has hardly yet recovered from the fierce onslaught of logical positivism in modem times, was of the essence of Islamic philosophy and the realm of its chief contribution to the history of ideas. . Two factors helped to place it in a position of eminence among the intellectual disciplines that reached the Islamic world from Greece, viz. the classical and the religious. Aristotle had justified it in the short opening phrase of his own Metaphysica on the basis that 'all men by nature desire to know.' Philosophy springing, in his view, from primitive wonder and moving towards its abolition through an understanding of the world, was an effort 'to inquire of what kind are the causes and the principles, the knowledge of which is Wisdom'; particularly of the first and most universal causes. And a single supreme science of metaphysics, devoted to the study of the real as such was possible, he maintained, and may be fruitfully pursued. The impact upon revealed religion proved a more powerful factor. Transcendental elements had already found some place in classical philosophy, though the system remained fundamentally rationalistic. Through contact with the East, some religious influences were brought to bear upon it, as is reflected in the writings of the Stoics, the Neo-Platonists and other Hellenistic schools; but it continued separate and distinct. Now revealed religion set a rival and more formidable claim to knowledge. In the search after the ultimate realities, it asserted that faith in the human mind was vain, for the source of all knowledge was in God. Philo Judaeus attempted to reconcile classical philosophy with the tenets of his religion; and Christian thinkers made a
METAPHYSICS
bold and earnest endeavour in: that direction. And when the rational speculations of the Greeks reached Islamic society, and came face to face with a triumphant religion at the height of its power, the matter became an urgent and important issue. It finally came to be thought that it was in the realm of metaphysics that the relation between reason and revelation could be best explored, and that the fundamentals of religion could find rational justification and proof. Whether they divided philosophy into four branches as found in the Epistles, to comprise mathematics, logic, the natural sciences and metaphysics; or into three as A vicenna does after Aristotle, to include the higher science (metaphysics), the middle science (mathematics), and the lower science (the phenomena of nature); it was metaphysics that concerned itself with the ultimate realities. Logic, today of the essence of philosophy, was for them only an instrument, a tool in the search after truth. The arrangement of Aristotle's Metaphysica proved just as confusing to them as it is to modem scholars. Book Lambda, now considered an independent treatise and his only systematic essay in theology, became the basis of a distinct branch of study called the Science of the Divine (al-'llm al-1Iahi). Some confused it with the whole of metaphysics, others kept it separate; and their reactions to it were not all the same. Some, like the Brethren...of Purity, thought that the rival disciplines could and should be reconciled; others, like the theologians, repudiated any such possibility; and still others, like the FalcisifQ,propounded the belief that the fundamentals were different but complementary rather than totally negative to one another. In his evaluation of philosophy; Avicenna finds it necessary to assert that 'there is nothing in it that comprises matters contrary to the share (religious law). Those who put forth this claim ..• are going astray of their own accord." This Science of the Divine which, in spite of some confusing statements here and there, he, just like Aristotle, considered only a part, though perhaps the more essential part of metaphysics, is then divided into five separate
I
Tu'a Rasa'if, p. 80"
106
IO"J
AVICENNA
PROBLEMS
OF METAPHYSICS
sections. Metaphysics was to gain added importance because whereas Averroes found his proof for the existence of God in physics, Avicenna founded his arguments upon both physics and metaphysics. For Kindi metaphysics was 'the science of that which does not move,' and 'the science of the First Truth which is the cause of all truth.' Farabl divided metaphysics into three parts: The first dealing with beings in general and the states through which they pass; the second dealing with the principles of demonstration used in the theoretical sciences; and the third dealing with beings that are not corporeal in themselves, nor to be found in bodies; and about these he asks whether they exist, whether they are many or limited in number, and whether they all have the same degree of perfection. And finally this examination culminates in a demonstration that one Being could not possibly have acquired its existence from any other, 'the True that granted everything possessing truth its truth •.. who verily is God." For Avicenna the first impression received by the soul, and the first acquisition of certain knowledge, is the distinct notion of being; and as such it constitutes the first and the true object of metaphysics. Not just any particular being in space or in time, but 'absolute being inasmuch as it is absolute.' This thought which had been already suggested by Aristotle- became for him a central theme to be developed far beyond anything envisaged by the Stagirite himself. Thus if it be said that the central element of Platonic metaphysics is the theory of Ideas, and that of the Aristotelian is the doctrine of potentiality and actuality, that of A vicennian metaphysics is the study of being as being. With that as a starting-point we may seek the knowledge of things that are separate from matter. This is philosophy in its true sense; and it can prove useful in correcting the principles of the other sciences. It begins with the subject of an existing being (mawjud); and it is called the first philosophy because it leads to the knowledge of the first in existence.
I
In his approach to the inquiry Avicenna's background is a combination of religious orthodoxy as represented by the Mutakallemnn, rational explanation of dogma as propounded by the school of Mu'tazila, and syncretistic tendencies as favoured by the followers of the Isma'ili heterodoxy. Not that he adhered to any of these groups himself, in fact he had very little sympathy for any of them; but he certainly thought their views worth considering. His philosophical outlook was determined by Platonic and by Aristotelian thought with additions from NeoPlatonic and Stoic as well as late Peripatetic sources. Again he never followed any of these schools consistently, but traces of their doctrines can be found in almost all that he wrote.
*
*
*
*
Ibfa' ••• , p, 60.
108
• Metaph.,
IOO3a21.
Metaphysics was for Aristotle a matter of problems or difficulties (aporiaz). In like manner A vicenna turns from a description of the subject and its chief purpose to certain preliminary questions (masCi'il) that he feels should be first elucidated and solved. It is only then that its relation to religion can be properly assessed and determined. A vicenna chose to explore what Russell calls the No Man's Land dividing science from theology, the strip-narrow and unmarked-whereon they meet. This may have shown unjustified optimism on his part, yet he continued confident and persistent, All existing beings can be seen 'in a manner of division into substance and accident.' In Book E of the Metaphysica, Aristotle had pointed out that accidental or incidental being, and being as truth, were irrelevant to metaphysics. A vicenna could not disagree with the first statement, but the second was different. When using the resources of the whole subject to prove the existence of God, one of whose attributes was 'the truth,' he could not very well agree on that point. He therefore devoted some attention to the differentiation between 'the truth' and 'true,' a logical distinction to which he gave an ontological significance. The categories other than substance were mere concomitants. Classi-
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AVICENNA
PROBLEMS
OF METAPHYSICS
fication into them was like division according to differentia. And the classification into potentiality and actuality, the one and the multiple, the eternal and the created, the complete and the incomplete, the cause and the effect, is like division according to accident. The existence of substance and its distinction from the other categories was self-evident to Aristotle, and Avicenna accepts the substance-accident division which so much was to occupy his successors and the Scholastics after them. Like Aristotle he maintains that 'all essence that is not present in a subject is substance; and all essence that is constituted in a subject is accident.' Substance can be material or immaterial; and in the hierarchy of existence it is immaterial substance that has supremacy over all; then comes form, then body composed as it is of form and matter put together; and finally matter itself. Substance could be in different states. Where it is part of a body, it could be its form, or it could be its matter; and if it is entirely apart and separate, it could have a relation of authority over the body through movement and it is then called 'the soul'; and it could be entirely free of matter in every way and it is then called 'an intellect.' This leads to the opposition between matter and form so familiar in Aristotle. Matter is that which is presupposed by change-in position, in quality, in size, and in coming into being and passing away. But is there such a thing as matter? A vicenna tries to assure himself of its existence. A body is not a body because it has actually three dimensions. It is not necessary to have points and lines to make a body. In the case of the sphere there are no such intersections. As to the plane surface, it does not enter into the definition of a body as body, but of body as finite. And the fact of its being finite does not enter into the essence of it but is just a concomitant. It is possible to conceive the essence of a body and its reality, and have it confirmed in the mind, without its being thought of as finite. It can also be known through demonstration and observation. A body is supposed to have three
dimensions and no more. It is first supposed to have length, and if so then breadth, and if so then depth. This notion of it is its material form, and it is for the physicists to occupy themselves with it. The delimited dimensions are not its form, they fall under the category of quantity, and that is a subject for mathematicians. They are concomitants and not constituents and they may change with the change in form. Then there is the substance which constitutes its essence. This is constituted in something and is present in a subject which in relation to form is an accident. 'We therefore say that the dimensions and the material form must necessarily have a subject or prime matter (hayula) in which to be constituted.'! This is the substance that accepts union with material form to become one complete body with constituents and concomitants. Yet in the scale of existence form is superior to matter. It is more real. Bodily matter cannot divest itself of material form and so remain separate. Its very existence is that of one disposed to receive, just as that of an accident is an existence disposed to be received. Form is what gives unity to a portion of matter, and form is dependent upon disposition. Under Platonic rather than Aristotelian influence A vicenna may be thought to give to form a superior reality which is somewhat degraded when united with matter. Thus in his view intelligible reality is superior to sensible reality. The connection of form with matter does not fall under the category of relation, because we can imagine form without matter and matter without form. Could one be the cause of the other? Matter cannot be the cause of form, since it has only the power to receive form. What is in potentia cannot become the cause of what is in actu. Furthermore, if matter were the cause of form, it ought to be anterior to it in essence, and we know that in the scale of existence it is not. Hence there is no possibility of its being the cause. Could it then be the effect of form? Here there is a distinction to be made between separate form and a particular material form, Matter may lose a particular form only
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no
were inclined to the belief that matter existed before form. for instance. in them what is potential is not prior at all.' As for Aristotle.. It is true that in certain corruptible things potentiality comes before actuality with a priority in time. In fact he states in the Shifli.IliihiYyiit." The problem of the one and the multiple had to be considered because 'the One is closely connected with the being who is the subject of this. :J ~1 1 '" Najiit. science. But in universal and eternal matters that are not corruptible. the efficient and the final cause. God is actual and so is form. or it could be one as an absolute number. and that the Almighty changed their nature and put them into a fixed order. This is the conception of religious lawgivers.. There was some conflict between the religious and the ArisI rI Ij I i PROBLEMS OF METAPHYSICS totelian views regarding the priority of potentiality and actuality. and matter of the subject.' The agent and what is disposed to receive are prior to the effect. that 'the causes are four. Many of the ancients. Here then they both depart from Aristotle and under Neo-Platonic influence draw nearer to religious belief. . 112. that God took over matter and gave it the best constituent form. or from it comes evil. but the form never precedes in time at all.. The final cause is the most important. 'Cause is said of the agent •.• and cause is said of the matter . the formal. and it is what conI . There is a manner in which the One in number could actually have multiplicity in it.. calls the Giver of Forms (Wahib al-$uwar) known to the Scholastics as Dator [ormarum. It is either individual or it is general ••. it resided in the union of the two. The cause of matter is form in conjunction with a separate agent whom he. just as Aristotle had done in this connection. Actuality is prior to potentiality. . and form of the primary matter. The reality of what is actual comes before the reality of what is potential. are always actual. or distant it is either in potentia or it is in act~. It must be constituted together with a substance that must be actual. and Aristotle claimed that actuality came first. This deterministic attitude is one of the essential features of the A vicennian system. and that the supreme agent gave it that form. because potentiality does not stand by itself.. All that was because they insisted that as in a seed. And others contended that the eternal was the great darkness or the chaos of which Anaxagoras had spoken. or it could potentially have multiplicity. The theologians insisted that potentiality was prior in every respect and not only in time. And Avicenna concludes. I " ~'1 'j .. potentiality was prior to actuality. Matter is potential. p. it is either in essence •. even if they are particular. A vicenna says. And the formal he divides into form of the compound·.• or it is by accident. together with Farabi. This has led some to believe that for him there are six causes. that 'what is in actu is the Good in itself..J . but not of the potentiality of non-being ('adam).. and the effect follows necessarily from the causes.' Onen~~s is asserted of what is indivisible. in that case it would be one in composition and in combination. For the Sragirite reality did not belong either to form or to matter." The material and the formal cause Avicenna is inclined to subdivide each into two. All the Islamic Falasifa accepted the four causes: the material. whether it be in genus or in species or in accident or in relation or in subject or in definition.• and cause is said of the form •. and cause is said of the end •. contrary to the views of the theologians. and what is in potentia is the evil. The material he divides into matter of the compound. 113 . and each of these is either proximate . all the four causes are required to produce an effect. in that case it is continuous and it is one in continuity. We cannot explain change without it. This leads to the theory of causes. 83.AVICENNA to receive another. -The doctrine of matter and form is connected with the distinction between potentiality and actuality. This agent is the active intelligence and in the last resort God Himself. The eternal beings. for 'the chief agent and the chief mover in every thing is the end. SlUfii. the physician acts for the restoration of health. The multiple is the number opposed to one. And there were those who said that in pre-eternity these material things used to move by nature in a disorderly manner.
4. attention may now be directed to the fundamentals of Avicenna's thesis. And he complains that 'most of those who philosophize learn logic but do not use it. which was a constant thought in the minds of Islamic thinkers. Unity.. and we find it continuously repeated. Even if we suppose ourselves to be in a state where we are completely unconscious of our body. p. It might also be thought that the form which philosophy had taken in Islamic lands had something to do with it. Essence is one thing. or in relation to something else. Arabic trans. Objectively we gain the impression of being through senseperception and ahysical contact with the things around us. 365. 105W2. Unity is the concomitant of a substance. it became current in Islamic philosophy. A vicenna insists. we ask are they necesary or possible. to be described in the next chapter on Psychology.' Although this was later corrected by another translator. cr. The tendency is of course Aristotelian.. t~ey ~ltimately revert .' He is also inclined to think m terms of thesis. Vol. and logic does not occupy him excessively. It was stated above that for him the concept of being is the first acquisition of the human mind. almost a tradition that has persisted in the East down to modern times. or it is predicated of accidents. the error for some reason persisted. p. . But there are two elements to it. drew attention to this and tried to show its similarity to the Kantian method of thought. 4 Metaph. 108. and we find an ancient lexicographer saying 'and so one would not be a number.. Being is not a genus. This is so when we are trying to analyse being. is not the essence of anything. It may be supposed that the inclination was strengthened by the polarity between philosophy and religion. The accusation-so often repeated-that A vicenna was apt to compromise in his attempt to bring about a rapprochement with the principles of religious thought. It is well to remember that though he is essentially a metaphysician. and cannot therefore be divided into different species. became a distinctive feature. 1 Najiit.'3 There is also a gross mistranslation of a passage in Aristotle's Metaphysica4 where the translator who knew no Greek and was translating from Syriac. loses its point when we find Comperz describing Aristotle as the great compromiser. though by definition is not one.'1 It is reflected in the assertion of many Islamic philosophers that 'one is not a number'.. It may be a multiple in an absolute sense. \ . and if necessary. There is first Plotinus who in the Fifth Ennead puts it down that 'the One is not one of the units which make up the number Two. But when we observe beings. One is essence and the other existence. he constantly uses logical distinctions and the whole resources of what was for him only an instrument and a tool in establishing the basis of his arguments and in constructing the vital points of his metaphysics. we are still aware of the fact that we are and we exist. writing some fifty years ago.v There could be two sources for this notion.~ ' . It is only an attribute that is necessary for its essence. p.. Carra de Vaux. . potentiality and actuality. and these may be separate from one another or unified. are they so of their own account or as a result of some outside agency? And we come to the logical 115 . Then comes the curious statement that 'the smallest number is tWO.AVICENNA PROBLEMS OF METAPHYSICS tains one. matter and form. The knowledge of the concept of being is arrived at both subjectively and objectively. This is shown by the illustration of the man suspended in the air. Inge: Philo». 152. of Plotinus. Avicenna says. and then it is qualified as being one and existing. Thinking in terms of contraries as reflected in substance and accident. " '1 ~ 114 .. makes the statement that 'one is not a number. However that may be.3-2.to the~r intuitions. it is subsequent to matter. Bouyges. Dean With some preliminary problems surveyed. ann3 thesis and synthesis.. He finds a special significance in definition and gives it an application much wider than the purely formal one. Unity is not a constituent. " * * * * ~ " I • Jurjani.' As in his logic Avicenna devotes a section of his metaphysics to the principles' of definition and its relation to that which is being defined. 2. edit.
Afnan: Lexicon. And that is what is commonly called creation. otherwise it would not be a thing. that does not mean that the realiry. there must be that to which it is attributed. is other than the existence (wujud) that goes with its assertion. It enters the quiddity of a thing and is part of it. i • I TO Tl. there is an intervening process. necessary for the subject to be what it is. the non-existent would have an attribute. And that would mean that the non-existent exists. since what is meant by a thing is usually associated with the notion of existence. and for whiteness a reality that is whiteness. and in Scholastic Europe as well. then. without which the thing cannot be conceived. • Enneads. Was this an original contribution on his part? Some have declared it the first of the two outstanding contributions that he made in the field of metaphysics. A thing could be conceived by the mind and yet not exist among external things. Everything that has a quiddity can be believed to be existing in itself or imagined in the mind by having its part present with it. 921)10. An attribute may be (I) essentially constitutive (al-dhatiyal-muqawwim). There is the reality of a thing which is the truth that is in k-And there is its essence which is that by which 'it is what it is. 'Everything has a particular reality (~aqiqa) which is its essence (mahryya). Post. Could a thing be absolutely non-existent? If by that is meant existing in the concrete. it has been associated with his name. This may be called their particular existence. The fact is that even if it did occur to others before him-and the significance of their statements has been stretched sometimes to prove that it did-none of them followed up the idea and applied it in the manner that he did. of the triangle is the same as that of the figure itself.and in Fiirabi. Anal. We can define and imagine man irrespective of the fact whether he exists in the concrete or not. If we say that figure is predicated of a triangle. and body in relation to man. which is absurd. Cf. then it may be allowed.v I Thus A vicenna transforms a logical distinction which Aristotle had drawn between essence and existence into an ontological distinction of great import. To attribute a certain quality to a subject does not necessarily imply that the significance of the quality is the same as that of the subject. though in fact they are entirely separate. But there cannot be a thing that the mind or the imagination cannot conceive.t in Plotinus. The concept of being comprises both essence and e~stence. elvat. and he is quite conscious that it is essentially a logical distinction. Thus for a triangle there is a reality that is triangle. however. Significantly. II6 II7 . Is this process conscious and direct? It takes place necessarily. no information can be given.AVICENNA PROBLEMS OF METAPHYSICS conclusion that beings may take three forms. Take the subject-predicate statement. Should we suppose that there is some information. But all throughout the East.. and it is known that the reality of everything which is particular to it. possible or impossible.p. 3 'Uyiin al-Masii'i!. and of what is absolutely non-existent. And if it has a reality other than the fact that it exists in one I 'I . But between what is necessary of itself and what is possible of itself and necessary through the action of some separate agent. Perhaps in the Isharat-a late and reflective composition-it is expressed best. Information is always of what can be realized mentally. He drew conclusions from it that can hardly be attributed to any of his predecessors.3 A vicenna himself nowhere claims to have been the first to make this distinction. They could be necessary. It is part of its definition. i. VI. neither in the form of an assertion nor of a negation. such as in the case of figure in relation to triangle. " I . Let us now tum to the texts for further explanation. it is in discussing logic that he raises the matter.'1 And there is its actual existence. It has nothing to do with the notion of existence. lliihiyyiit. And yet in none of his works do we find the subject treated as fully as might be desired. through successive stages of emanation proceeding from the supremely Necessary Being who is God. Others have found traces of his distinction in Aristotle. • Shifii.. The idea of an existent being accompanies a thing. because it either exists in the concrete or in the imagination and the mind. and if there is an attribute.e.
Post. T6 Tt ea'nv. It may be (I) in an absolutely particular manner. is a constitutive of it.. These considerations have been compared with a passage in Aristotle! where he raises similar questions. and that ~t is impossible to accept the existence of what cannot be sensed in its substance: that that which is not identified by its I ~ . Or it may be (3) a non-concomitant accidental. If. . ' '1 I :~ Anal. and that is not constituted by it. but that A vicenna had the insight to apply it in the construction of a system that he was to make entirely his own. Ideas grow out of other ideas. Mil Euwa.' such as in a triangle where the angles are equal to two right angles.. and the particular manner in which it is said..' but as a result of the sensible perception that we have of his parts. Or the answer may be (2) according to the common factor found in differert things. A thing may have many attributes.AVICENNA PROBLEMS OF METAPHYSICS or other of these two forms. the quest after originality is an idle pursuit. And the causes of its existence also are other than the causes of its quiddity. yet it is what it is not by one but by the sum-total of all the essential attributes.IA . they are suggested by random thoughts. If it were a constitutive. Logicians have failed to make the proper distinction. This confirms our previous statement that the logical distinction was not new. Here again he gives an example which Aristotle had given in the Metaphysica. and can be developed out of all recognition. not because of our comprehension of the concept 'man. . and one would doubt if it actually exists in itself. The answer may take three forms. Thus Avicenna's comprehension of essence does not differ much from that of Aristotle as found in Book Z of the Metaphysica. In that case 'it is what accompanies quiddity without being a part of it. in the concrete or in the mind. " \ " • . is one thing. rapidly or slowly. and the meaning that is conveyed by its name. 118 .• "~ . An attribute may also be (2) accidental concomitant non-constitutive. since definition like demonstration makes known just one single thing at a time? What man is. all of which are essential. it would be impossible to form a proper idea of its meaning without its constituent parts. and already existed in Aristotle. And what of the notion of existence? It is commonly supposed.' yet at that.:t '1 '. as in the way a definition points out the quiddity of the name. not its existence nor whether the name accords with it. Avicenna says. definition can prove what a thing is. In philosophy as in many other things. We could not obtain for the notion of humanity an 'existence in the mind'. early stage the conception was real and helpful.' and that 'a word may have an essence. No such difficulty occurs in the case of man. Or again it may be (3) according to the particular and the common factors together. Thus humanity is in itself a certain reality and quiddity. What was necessary and important for his chief argument was to stress its distinction from the notion of existence. It is just a correlative. can it also prove that it exists? And how could it prove essence and existence at the same time and by the same reasoning. such as man being described as young or old. And there is a difference between what is expressed in answer to the question 'what is it?' and what is included in the answer by implication. in a sitting or standing posture. He who asks the question seeks the quiddity of the thing which is found by adding up all the constituents. and the fact that he exists is another. that the existent is what the senses perceive. What the questioner wants to know is the essence of the thing. 92b8-n. Not that its existence. Modern philosophers may think that the idea of essence is 'purely linguistic. The predicates that are neither constitutive nor concomitant are all those that can separate themselves from the I subject. then existence becomes a notion that is added to its reality as a concomitant or otherwise. he asks. thus 'a reasonable animal' denotes man. But what exactly is meant by essence for which Avicenna also sometimes uses the word reality (~aqiqa) and at other times self (dhiit)? Essence is what is asserted by an answer to the question 'what is it'?! It should not be confused with the essential attributes of a thing which are more general. easily or with difficulty. but a thing cannot.
!s!ziiriit. it is quite possible that the quiddity of a thing should be the cause of one of the attributes. And it also has the reality of triangularity. possible or impossible. and there is nothing prior to existence itself.J ~ 1 . 'All true being is true according to its essential reality. we tum to t~e diffe~entfo~msthat being could take. and they constitute it in so far as it is a triangle. is necessary to prove that this is not the case. it should be noted that the originating factor which brings about the existence of a thing that already has . And it is agreed that He is One and cannot be pointed out. or that one of the attributes be the cause of another. It could be necessary. if the latter is one of the ends that actually take place. Man inasmuch as he possesses a unique reality or rather inasmuch as his fundamental reality does not alter with numbers. Hence the possible beings that were made necessary were caused. · 11 . has no share of existence. And this could be effected only through the power of some intervening force that would have to be a necessary being independently and by itself. But its existence depends on some other cause also besides these.'! And again. but it is not possible that the attribute denoting existenceshould be due to a quiddity that is not conditional on existence. or with respect to that in which it is found.. and this is the efficientor final cause..constitutive causes to its quiddity. whereas the other attributes exist because of quiddity. or should be due to some other attribute. like the states of a body. In other words existence is different from the other attributes in that quiddity exists as a result of existence.AVICENNA PROBLEMS OF METAPHYSICS place or position like a body. And 120 he immediately goes on to say: 'If it is the First Cause it is the cause of all existence. The reason for that is that the cause comes first. Neither form nor matter nor the end could find precedence over the agent. Opposed to those who have declared it the second original contribution of I ·. How then could what through Him attains all the truth of its existence. is a cause by means of its quiddity. such as a triangle represented by lines and a plane surface. and it is the effect of it in its existence. They are possible beings in themselves that have been made necessary. 121 140• . or it may be what brings all of them into existence and unifies them into a whole. may be the cause of some of these. exists in the concrete. All things that we sensibly apprehend may be thought to be necessary. is not something that the senses can perceive. Again the question arises whether this classification of being according to the forms that it takes was or was not an original contribution in the field of metaphysics.J ·1 . And the final cause on account of which the thing is. * * * * From an analysis of being into essence and existence. For example the reality of a triangle is bound up with the plane surface and the line which is the side. and the agent that made them so was the cause. and of the cause of the reality 'of every existent thing in existence. and the final cause is 'an efficient cause for the efficientcause. or it may be caused in its existence. however.' And the same is the case for all universals. p. It is not the cause of its causality nor of the idea that it represents. It is thus seen that for Avicenna the efficient cause is the most decisive. . For the idea which it represents belongs to the causality of the efficient cause. and being the prime agent he is the First Cause. objectively they represent the different ways in which they are related to one another. Being is not a genus and these are not its ~pe~ies. but 'pure intelligible. But are they necessary by themselves? They possess no power to make themselves so. Only a little thought.' A thing may be caused in relation to its quiddity and reality.Subjectiv~ly they are the different forms in which being IS mentally conceived.' In seeking to know whether a thing. and it might be thought that these two were its material and formal cause. such as in the case of form. The efficientcause is a reason for the existence of the final cause. that does not constitute its triangularity and is not part of its definition.
contrary to the first. the necessary denotes 'continuation of existence'. The necessary matter represents a state of the predicate in its relation to the subject.. 'The differencebetween mode and matter. It may also be said that the possible is that on which there has been no judgement passed in the past and in the present. And matter is a state of the proposition in itself. the impossible 'continuation of non-existence'. Necessity is divided into the absolute and the conditional.' The way in which Avicenna's predecessors-and he may be referring to the theologians hereattempted to definethe necessary and the possible was most unsatisfactory. they take in its definition either the necessary or the impossible .2.3 . 'If they want to define the possible. In a proposition there are three essential parts. and at all times. 2. Absolute necessity is such as in the statement 'God exists. but so long as the movable continues to move.4. they take in its definition either the possible or the impossible.. With regard to the modes. but there may be one in future..AVICENNA PROBLEMS OF METAPHYSICS Avicenna.' They are apt to argue in a circle. and the possible indicates neither the one nor the other. and this is not Aristotelian. 'The necessary heing is that being which when supposed to be not existing. there remains its transposition t~ the plane of metaphysics. Definition is essential. without determining whether it is necessary or not. . Or the condition might be the continuance of the subject being qualified by what was stated with it. 'is that mode is a term fully expressed indicating one of these notions. and its application for the purpose in view. The impossible need not detain us. there is a matter (madda) and a mode (jihat) to every proposition. Here he introduces what we take to be the idea of contingency. For instance in the statement 'Zaid could I Najat. and by the not possible what is impossible. are those scholars who insist that there are traces of this idea in Farabi. the subject. and that which denotes the relation between the two. 12.' the matter is necessary and the mode possible. I .. With the logical basis established.if '. as when we say: 'Man is necessarilya talking animal': we mean so long as he lives. According to another division.i . 'If J 1 . possible or impossible. '1 " .' " . an impos12.0 . the mode and the matter might differ. and each of these may be necessary. where it becomes necessary without any doubt. "I . such as the state of 'the writer' in man.' he adds. The truth will be always in the affirmative and the negative will be out of consideration. The impossible matter represents a state of the predicate where the truth is always in the negative. though some scholars insist that there is no notion of coritingency in Avicennian thought. it is a distinction already anticipated in Aristotelian logic to which Avicenna gave an ontological sense and which in his own special way he applied to new and fruitful fields.' which does not mean absolutely.. The common people understand by possible what is not impossible. But specialists found a notion of what is neither necessary nor impossible. moreover the whole idea may have been suggested by the claim of the theologians who basing themselves on the doctrine of creation ex nihilo. superfluous in others. . and the affirmative is not to be considered. possibly be an animal. distinct from the common idea of it.. These divisions and subdivisions which he is so fond of making. such as the state of 'the animal' in man. and if they want to define the necessary. He calls it possibility in the special sense. and the two may not agree. nor as long as it exists. And everything for them is either possible or impossible with no third situation. the predicate. Again. such as 'every thing that moves changes. placed the world and indeed all creation in the category of the possible.' The conditional might be dependent upon whether the existence of the thing continues. such as the state of 'the stone' in man. And the possible matter is a state of the predicate where the truth whether in the affirmativeor negative is not permanent and for all time. p. but he attached importance to them in building up his argument. since 'existence is better known than non-existence. might be thought evident in some cases and.'! In other words in one and the same judgement. not expressed.
' Here again there are distinctions to be made. then it is considered a possible being with an equal chance of existence and non-existence.' And again. Actuality may be equated with the necessary being and potentiality with the possible. 12.. necessary being mayor may not be necessary in itself. Actuality and potentiality are closely related to the distinction between necessary and possible.. and 'all possible being in essence. When it is necessary 'in essence' the supposition of its ~on-existen~e becomes an impossibility. or still. if it does actually attain existence.' Obviously this is because the necessity of its existence is bound up with and follows from some association or relation with another thing. but together with it. or in the sense that it is something potential and may develop into some sort of being. It was said that all necessary being through association with what is other than itself. once 11. it would cease to be a necessary being. to the possibility of it. becomes a necessary being in association with another. The inverse also is true. God is the Necessary Being. the existence of a possible being is either through its essence or as a result of some particular cause. and together with something else simultaneously. .' The reason for that is that it either actually attains existence or does not. when the distinction between essence and existence is applied to necessary and possible beings. In like manner a possible being may be possible in the sense that in its existence or nonexistence there is no element of impossibility. it may stand for all things that are in their 'pr?per existence. Combustion is not necessary in essence. becomes necessary. For instance the number four is not necessary in essence it becomes necessary only when two and two are put .AVICENNA PROBLEMS OF METAPHYSICS sibility occurs from it. If it is through its essence. If it fails to do so it would be an impossible being. then that existence must be either necessary or not. becomes in essence a possible being. but he has his arguments for what makes a necessary being really necessary.' This last sense was the one held by the theologians.' Consideration of the essence alone may be applicable to the necessity of a being's existence. On the other hand. There remain only the first two cases. they became themselves necessary. 'We call the possibility of being the potentiality of being. A. In God as the Necessary Being they are one and the same. Nor is the religious application far to seek. We have followed Avicenna's reasoning in order to show the manner in which he draws the distinction between the necessary and the possible being and the relation between the two. would be a necessary being in association with what is other than itself. The last case must be ruled out. So it may be said that 'everything that is a necessary being through association with something else. then that would be a necessary not a possible being. a thing cannot be a necessary being in essence.5 . If it is through some cause. It ecomes necessary only when fire and some inflammable material are brought into contact with one another..4 it attains existence. It is something that only when put with another besides itself. ·1 ~ . or to the impossibility of it. cannot exist in association with another thing either. it is found that it is only in possible beings that they are different. and through association with what" is a necessary being. ! ~i . And association and relation cannot have the same consideration as 'the essence of the thing itself. And a possible heing is that which when supposed to be not existing or existing. And so what is a possible being in essence. is itself a possible being in essence. . For in the latter case if that other thing is removed. But it was originally in that state and it came into existence. since that thing the existence of which is impossible in its essence. an impossibility does not occur from it. It may therefore be concluded that the fact that it has come into existence proves that 'its emergence into existence was a necessity. Furthermore. then it cannot exlst without that cause.b together. If it is true. All creations are possible heings brought into existence through a process and for a reason that was absolutely necessary. and we call the bearer of the potentiality of being which possesses the power of the . but when not necessary In essence. It might be thought that the differentiation with its logical origin and form is more linguistic than real. Furthermore.
That is what is called creation. Subscribing to the Aristotelian conception of the eternity of matter. and the agent cannot create unless the thing is in itself possible." Hence there is a notion of time involved in the whole matter. p. Its non-existence could not have been together with its existence. It is not a substance in itself. Najiit. .1 . or multiple.'> Furthermore. He had already assured himself that there 1S such a thing as matter. Was this matter to be considered I eternal (qadim) as Aristotle had taught. 'or a quiddity to something other than itself. or created (mu~dath) as the theologians. 373.s In both cases it is a proof of the existence of time. which means that there was a period prior to its existence which has expired and is no more. nor is it changeable. There creation was explained in Neo-Platonic fashion as successive stages of emanation proceeding from God. To be created everything must needs have been a possible being in itself. he thought. and comes face to face with one of the most challenging and uncompromising problems in the conflict between religion and philosophy. or it may be eternal with respect to time. The concept of creation ex nihilo is not Greek." And as such. And what constitutes that period is 'either a quiddity to itself' which in this case is time. Its existence is not conditional upon anything other than itself.it is a notion present in a subject and an accident to it.AVICENNA PROBLEMS OF METAPHYSICS existence of the thing. and that prior period was terminated. 1 . there are some distinctions to be made. Was there a possibility of reconciling the claim that the world was eternal. and in the other 'it is that for the age of which there was a beginning. had to reason it out for himself. must have been preceded by time and matter. p. p. 127 219. and by adopting the theory propounded in the so-called Theology of Aristotle. insisted? Here. Now the notion of the possibility of being can exist only in relation to what is possible to it.' That which is a necessary being in essence 'is pure truth because the reality of everything is the particularity of its existence. I ~ . I 'I j . • IhiJ. . In one sense 'it is that for whose essence there was an origin by which it exists'.. justifiably from their point of view. 'the necessary being is the Truth in essence always. and the doctrine that it was created by God through His own wish and will out of total non-existence? Fiirabi had thought that he could take an intermediate position by doubting that Aristotle really meant that the world was eternal.' And the word 'created' also has two distinct meanings that should not be confounded.. which is its time. 1 :1 " Najiit. a subject and prime matter. A prior-period (qabliyya) during which it was nonexistent. It does not depend on the ability or inability of the agent to create. p. who was to take the same view with some minor modifications. and it has been stated that the possibility of being is the potentiality of being. and has no cause like possible beings. and with respect to the latter 'it is that for whose age there was no beginning. and there was a time when it did not exist. the Necessary Being is pure Good. as actuality. * * * * Between the Necessary Being and all possible beings there was a stage and a process involved. A thing may be eternal according to essence. The two things are entirely distinct. Here Avicenna is on delicate ground. It must have been earlier.. With his rational temperament he was deeply attached to Aristotle. It does not stand in relation to any other thing. actually parts of the Enneads of Plotinus. Let us follow this argument. Yet as a fundamental principle of religion it could not be lightly dismissed. but he was reluctant to depart from such an essential principle in his Faith. and the possible being is true in virtue of something besides itself. Everything that had for its existence a temporal beginning aside from a creative beginning. Avicenna. and Aristotle did not produce any theory about this. or in association with anything other than its own essence. and previous to that was altogether non-existent. . According to the former it is 'that whose essence has no origin from which it exists'. it may be shown that all temporal creation is invariably preceded by it. 218. 358• 126 • uu.
According to their view there are two different states to the thing on . There must needs be a first. Icha/q. 12. Moreover. who grants existence after nonexistence.' In other words cause and effect in this case are simultaneous.' The non-existence of the thing is not a condition. a cause also may be ei~her necessary in its essence or necessary through some other thing than that. God is also the final cause. need not have a cause in itself. He is the final cause in the sense that He is something that always is to be. it becomes a creation in itself. Mnan: Lexicon. But what exactly is meant by creation? 'Creation means nothing except existence after non-existence.AVICENNA PROBLEMS OF METAPHYSICS And that subject which is in a potential state is what we call primary matter.2 And he uses the term preferred by the Falasifo to what the theologians called creation (~udii. God is thus the cause of all causes and the end of all ends. but due to the fact that he is 'the cause and a necessary being at the same time. There is first a previous non-existence and second ~n existence in the present. He is not an agent only because he is the cause. then the effect is not necessary in itself. Surely the agent could 'have had no influence upon it during its state of non-existence' and his influence began only after it was brought into existence: The fact that it was non-existent in its essence could not have been ~ue to the infl~ence of the agent. but becomes sa.acted.. This is the meaning of what philosophers call bringing into original existence (ibda'). 'the cause is for the existence only. Contrary to what people suppose.' there is no priority in time whatever between cause and effect. But does cause always precede the effect? It should be realized that 'the. If It should be necessary. 'And so every created thing is preceded by matter. So the agent whom the people call the Agent is not given that name for the reasons that they proffer. ~ ~ • . then its existence would be more true (a~aqq) than the existence of the possible. Now if it be imagined that the Influence commg from the agent. and the cause in essence either necessary or possible. be a priority in essence? Like all beings.J .' If it so happens that it was previously a nonexistent thing. so that 'every effect comes to be after not-being with a posteriority in essence. cause." If matter is eternal then creation can no more be ex nihilo.. For distinctions between ihdii'. But if there is no priority in time. "..which the agent. In full agreemen~ WIth the Stagirire. then in that case the agent E '. it is just an attribute and an accident. ~ t • · 1 . All the Islamic philosophers had insisted on and emphasized that point. did not take place because the thing existedetemally. . through it. In the case of this originating act which implies 'bringing something to be (tayis) after an absolute non-beingness (laisa). So a thing in so far as its existence is said to have been from non-existence. There is only priority in essence.th). cf. Should that come to pass. In all cases the cause would be prior in essence a~d it would ~e. A vicenna holds that the chain of causation ~a~not be traced indefinitely. In the latter case once it attains necessity another may proceed from it. . it becomes either a necessary or a not-necessary being. There is no point in what 'the infirm among the Mutakallumiln' say.' The two are interrelated. why and how could there I 1 SlUfii_ /liiAlyyiit. In fact He is the efficient cause by being the final cause as well. if not in the same words. But contrary to their declarations. must be together with it and not precede it in existence. and can only be God. w~o is the cause of all causes.essential causes of a thing that bring about the actual existence of the essence of that thing. the effe~t would be in e~sence ~ossible. . otherwise it should not be called a creation. taA:win. and which constitutes the bringing into existence of what did not exist. Aristotle had said practically the same thing.' While the notion of creation to which the religious-minded were committed implied that the process is conditioned by a priority in time. in like manner it is not possible to follow the end indefinitely. also m?re true than the effect. just as it is impossible to retrace the original cause indefinitely. He IS the efficient cause-a point which the theologians liked to stress. And after coming into existence.8 . And if it is possible. has .
If in their essence. And again. they should be viewed with relation to Greek thought on the one hand. The chain of causation cannot he retraced indefinitely. and the cause of both may he the same. If it is necessary. The theologians maintained that the world and all therein was in the category of the possihle (jii'k). essentially possihle causes without end at one time.. The chain of causation ends in him. either in its state of non-existence or existence. If they be created. supposing all beings were possihle. it would he what we seek. may be described as his creation and useful for his own being. Then the same argument holds good with regard to the cause of their permanence. It must therefore he a necessary heing. Theologians may teach that God as the efficient cause is in the act of continually creating accidents that subsist only through His action. and the conditions of his heing cannot hut make him a necessary heing. In which case the creator would be the creator of the existent.l . Thus the Almighty is omnipotent but He does not create ex nihiIo. He was an artificer rather than a creator ex nihiIo. pp. who is the first cause and the originator of all. Hence for Avicenna as for Plato and Aristotle. Cf. there must he some original heing that was able to give it existence. Again the chain of causation cannot he retraced indefinitely.. then the cause of their permanent existence must he either in their essence or in something else. There cannot he for an essentially possihle heing. and orthodox religious doctrine on the other. then there must be a cause for their creation and a cause for their permanence. he repeats. and the cause of their permanence will end in a necessary heing that gives permanence to created beings. and that every existing being could be either necessary or possible. how then could he he the cause of his own existence and ahle to proceed from himself? And again. if it is possible.. otherwise it could not have these qualifications and capacities. These are the religious claims that were hound to influence him and which he could not ignore. . His most renowned proof grew out of the distinction between essence and existence. God's act of creation meant the giving of form to pre-existent matter. They would either have to be created or uncreated. 347-8• 130 . a conception for which the religious-minded never forgave him. in whole or in part. they claim that the act is not legitimate and proper except after the non-existence of that which has been acted upon. Yet it is only when a new disposition makes matter ready to receive a new form that the old one disappears and God through the active intelligence grants a new form. So long as it is a possible heing . It may he argued that Avicenna starts with certain assumptions that mayor may not he warranted. only existence is. and that indicates his existence. that owes its existence to something else. . If they he uncreated. If he were not necessary. and upon it as a hasis constructs his argumentthat the existence of possihle heing necessitates the existence of a necessary being. Evidently there could be no creator to what was still in the state of non-existence. And the original heing must be the cause of its own existence and ahle to produce itself.AVICENNA PROBLEMS OF METAPHYSICS would be even more omnipotent because his action would have been eternally in progress. 131 " '. To be better appreciated. unable to produce itself. they would he necessary beings. . God gives form to pre-existent matter through the agency of the active intelligence which is the Giver of Forms. Najat. The thing which it is claimed that a creator brings into existence. There is no doubt. It must therefore he separate. if in something else then possihle heings. or in both states. These considerations are meant to prepare the way for the proof of the existence of God which for Avicenna is the consummation of all metaphysical speculation. and the threefold classification of being. There is a creator only for what exists. And that original heing could not he within it.! Although it was shown that non-existence could not be from the agent. hecause it is itself a possihle being. it would he for I us to show that it originated from a being that must he necessary. that there is existence. He accepts that.
a priority in essence and rank. The notion of possibility as an accident can only reside in a subject. Cf. and not a body nor in a body. From the Necessary Being who is one. Natural movement is from an unsuitable state to a suitable state. how does the world with all its multiplicity proceed from Him? Here the Neo-Platonic theory of emanation (foitf) proved helpful. J . it is equally true of and shared by the intelligences. Was there a contradiction involved? None whatever. but possibility is not a substance and cannot exist separately and independently. and from that there results this act of creation. Therefore possibility and creation are co-eternal with matter. In his own Physics he developed the same thought with certain modifications that were to infuriate the more faithful Aristotelian that A verroes was.. He had concurred with Aristotle's view that the world was eternal. There are three causes to movement: nature (fah'). and at the same time be an active will in the nature of authority and command that can originate movement. and agreed with the theologians that it was in the realm of the possible. Force can be ultimately reduced to the nature and will of the mover. and hence owed its existence to some cause. The capacity to think and as a consequence create is not special to the Necessary Being. when it reflects upon its essence. the nine spheres already enumerated under F"aribi. Or again. The idea precedes the actual thing. The first intelligence. . since the priority of the Necessary Being over the world of possible beings was riot a priority in time.AvicENNA PROBLEMS OF METAPHYSICS He did not reject the Aristotelian proof of God as the Unmoved Mover. applies equally in the case of movement and points to the existence of a necessary First Mover. Furthermore it is through the will of the Mover -so essential according to the religious view-that all existing things move. it remains to be seen how the act takes place. there proceeds through emanation the first caused (al-ma'lul al-awwal) which is also one. then God and the world are co-eternal. and the world proceeds from God. and the meaning of creation explained. for the separate substances. it originates in the mover. and God is One. the soul of the particular spheres proceeds from it. Avicenna follows along practically the same lines though more resourcefully and comprehensively.•t . . Will in order to be the cause of movement must be permanent and allembracing. And it is this twofold feature of the first intelligence that is the cause of it. is possible in its essence. It is a pure intelligence. because of being a form that is not in matter. when it reflects upon its essence. But there is a difference to be noted.. as the theologians maintained. And even in the case of attraction and repulsion and such-like.) . but like cause over effect. It is only in this manner that multiplicity comes to take place. The Necessary Being by an act of pure reflection creates the first intelligence which like Him is one and simple. the body of the particular sphere proceeds from it. And the first intelligence by reflection upon itself. And we saw how the existence of matter may be shown to be eternal. Hence the necessity which Avicenna so much emphasized in the case of existence. And in so far as it is possible. is equivalent to creation and produces the same results. and that subject is matter. Creation presupposes possibility. because it is itself created. He ponders His own essence. It in no wise emanates from the Necessary I . produces the first cause. . and after that generally accepted. * * * * With the existence of the Necessary Being established. . Here a problem is posed. In so far as it is necessary. and not divisible nor to be defined. It is thus the first of the separate intelligences. . and necessary only in association with the Necessary Being. But how exactly does this act of emanation take place? Thinking or contemplation. If it be accepted as a principle that from one nothing can proceed except one. 132 133 . Brief reference was made to the way in which Farabi under Neo-Platonic influence approached the problem. It was in itself a congenial conception that came to be adopted by Islamic mystics. will (iriida) and force (qasr). Hence it is not itself a cause unless it combined with something in actu.
But they differ in rank and order. In a similar manner and by a similar process. not by time. though the immediate one is the soul. . It isnot affected by the movement of the body and would not be associated with the faculty of the imagination of that body. 'The genesis of a thing is ~rom another thing. I but their succession is governed by necessity and determined by their essence.e. i. was to constitute the form and the entelechy or perfection of every sphere.. having the capacity for it in each individual case. The soul of the first sphere that emanates from the first intelligence.~ . The distant cause remains the intelligence. and their last was the active intelligence. • Najat. It is not able to cause motion at all except by way of provoking desire.. 'Iss.' But why does not the process continue indefinitely creating new and more intelligences and spheres? This is because the world is finite. and in consideration of its individuality not its species. is one and multiple at the same time. A similar triad proceed from the second intelligence. they were about fifty and more. SAifii. . it would be the soul of everything and not only of that body. and (3) the body of it which is its matter. t . a second intelligence emanates from it with the same qualities. and the form and body of another sphere. and individual species take the same form. a third intelligence.'! The function of the soul of a sphere. it may be asked if different bodies are made of a common matter. Finally. on what basis does individuation take place? This is in consequence of the matter which under the influence of outside agencies develops a disposition and potentiality to receive the form that it merits. is the form of the celestial sphere and the cause of its perfection. (2) the soul of the first sphere which is its form. Nor are they 'according to their significance entirely the same. In fact we should not think in terms of time. • ~ . and possibility as a result of its proper essence. . Though 'according to the belief of the first teacher (i. but by a conscious necessity meant to establish order and the good of the world. and the series of emanations stop where the world requires no more intelligences. the priority being only by accident. And what is the object of these successive emanations from the Necessary Being? The purpose is not governed by blind necessity.. Hence the first intelligence that possesses necessity as a result of its emanation from the Necessary Being. and it is the intelligence of the terrestrial world. Thus three things emanate from the first intelligence: ( I) the second intelligence.•• in fact one is not prior in essence to the other. not the sense of being after a thing. In other words the creative power is in the intelligence which is separate.. If it were separate in essence and in action. and where the last presides over the generation and corruption of the elements. Aristotle). Not a separate substance. for in that case it would be an intelligence and not a soul. Thus the proximate cause of the motion of die heavenly spheres is neither nature nor intelligence. And its relation to the sphere is similar to the relation of the animal soul which we have to ourselves.' there were only ten intelligences in addition to the first cause. in which Plotinus and Leibnitz among others believed. When marked by a determined quantity it becomes appropriate to take a particular form. Its conceptions and will are in constant renewal. p.e.· • I I . It is in alteration. And what is the exact relation between these intelligences? They are not all of the same species. ///iiAiyyat. and not in the soul which as the proximate cause brings about movement. And the body of it is due to the potentiality that resides in that intelligence. but that 10 the second there is an element of the first included in its substance •.' Even in substantial things. 134 135 . The process continues in succession until 'it ends in the intelligence from which our souls emanate.• and it is the part corresponding to its potentiality . I '. 'whose accidentality and attachment to movement was proved to you. AVICENNA PROBLEMS OF METAPHYSICS Being himself directly. but the soul. and one is more I to be preferred (aida!) than the other. changeable.' Every intelligence has its sphere independently with its matter and form which is the soul of it. the element of time is to be belittled. and not separate from matter. and we call it the active intelligence (al-'aql al-fo"ii/).
perceives through the vibration of the air that produces the sound. and accepts the Aristotelian explanatton. Sight is a faculty located in the concave nerve which perceives the image of the forms of coloured bodies imprinted on the I vitreous humour. the motive and the perceptive. with the belief in the passive process. Najat. 'All the sensibles convey their images to the organs of sensation and are imprinted on them.media to polished surfaces. Touch. a faculty located in the nerves distributed over the surface of the ear-hole. p. What is first perceived by the sense and then by the internal faculties is the form of the sensed object.61. dry and moist. t Najat. p. Hearing.' If the sense of touch is only one. and what is perceived by the internal faculties only is the meaning or intended purpose I ~ . But' what exactly is sensation? Aristotle's predecessors had treated it as ess. others only perceive. may be said to agree. at least as far as the mechanism is concerned. though its psychical functions are distinct from and above the simple mixture. 136 137 .' Then (3) there is the human which is 'the first entelechy of a natural body possessing organs in so far as it commits acts of rational choice and deduction through opinion. He himself had thought of it as the 'realization of potentiality.V AVICENNA'S definition of the soul does not differ from that of Aristotle. either mixed with the vapour in the air or imprinted on it through qualitative change produced by an odorous body. Smell. 2." The genesis of the soul is attributed to heavenly powers and it is preconditioned by a harmonious blending of the elements. like other Islamic philosophers.PROBLEMS OF PSYCHOLOGY CHAPTER V PROBLEMS OF PSYCHOLOGY . The animal soul has two faculties. . and grows and is nourished. There is (I) the vegetable which is 'the first entelechy (perfection or actuality) of a natural body possessing organs in so far as it reproduces. The soul as a 'single genus' may be divided into three species. and others perceive their meaning or purpose. The perceptive faculty may also be divided into two. . some are faculties that perceive the form of sensed objects. located in the nerves distributed over th: tongue..' Then (2) there is the animal which is 'the first entelechy of a natural body possessing organs in so far as it perceives individual things and moves by volition. distributed over the entire skin and flesh of the body perceives what touches the nerves . and like him he conceives of psychology in terms of faculties. Taste. The term 'internal senses' is probably of Stoic origin. either it gives an impulse or it is active." Of the internal senses. though the faculties included under it are found in Aristotle. some possess primary perception and others secondary perception. Avicenna refutes at length the Platom~ the~ry of sight ~s proposed in the Timaeus. perceives odour conveyed by inhaled air. and are then perceived by the sensory faculty. Where it gives an impulse it is the faculty of appetence and may be subdivided into desire and anger. thus producing a qualitative change on the tongue. The external are 'the five or eight senses.entially a passive process in which the sense-organs are qualitatively changed by the object. hard and soft. Some of these faculties can both perceive and act. located in the two protuberances of the front part of the brain. and the forms are transmitted through transparent . Avicenna. they are five. perceives the taste dissolved from bodies and mingling with the saliva. and where it is active it provides the power of movement.and what affects them thus causing change in their constitution or structure. smooth and rough-then they can be counted as eight. one perceives externally.' without holding to the notion as a purely mental activity. The motive is again of two kinds. if it is supposed to comprise the four pairs of contraries-hot and cold. ~S8. The waves touch the nerve and hearing takes place. • • I I. and in so far as it perceives universal matters. and the other internally.
' When only this amount of actualization has been achieved. Ghazali subscribed to it also. Next comes the faculty of representation. has a practical and a theoretical faculty. i. and so called because of its resemblance to primary matter. Other faculties in the animal are the 'sensitive imagination' which is called 'rational imagination' in relation to the human soul. In relation to the first it may also be called the actual intelligence. One of the animal internal senses is the faculty of fantasy. In Aristotle phantasia has a variety of functions. the second stage is termed habitus and the third the perfection of potentiality. imagination and estimation. located in the rear part of the front ventricle of the brain. to whom Avicenna is often indebted. The belief that the internal senses were located in the brain was of Galenic origin. it is called lntellectus in habitu (al-'a~l hil-malaka). As to the way in which the rational soul acquires knowledge. At this stage it is called the 'material intelligence. The human or. because the forms are acquired from without. and the retentive and recollective faculty which retains what the estimative perceives. A vicenna says. its relation to the forms may be in the nature of absolute actuality. which preserves what the sensus communis has received from the five senses.AVICENNA PROBLEMS OF PSYCHOLOGY of the object. both of which are rather equivocally called intelligence. The practical intelligence must control the irrational tendencies in man. With it the animal genus and its human species are prefected. and by not allowing them to get the upper hand dispose him to the consideration of knowledge from above by the theoretical intelligence. potentiality when only the instrument for the reception of actuality has been achieved. It is found in a slightly different form in Farabi. that of relative. second. leaving no trace of material attachments in them. These functions the theoretical intelligence performs in stages. because the first cannot actually think at all. the degree of receptivity differs with each individual. It may thus be said that the relation of the theoretical faculty to the abstract immaterial forms is sometimes in the nature of absolute potentiality. The much disputed origin of this classification is not Aristotelian. which belongs to the soul that has not yet realized any portion of the perfection due to it potentially. when they are present to it and it actually and knowingly contemplates them. or material. It has a certain correspondence with the animal faculties of appetence. The practical is the principle of movement of the body urging to action: deliberate and purposive.e. and the faculty of man becomes similar to the first principles of all existence. Some people come very near to 139 L 1 I. 138 potentiality as in an infant.itus. it makes them immaterial by abstraction. located in the forepart of the front ventricle of the brain. after which comes the stage of the per~ection of the original potentiality. At this stage it becomes the intellectus acquisitus (al-' aql al-mustafiid). and in this he had been followed by many of the Islamic Falasifo including Farabi. as it is commonly called. the estimative faculty which perceives the non-sensible meaning or intentions. and must have been influenced by Alexander's commentary on the De Anima. Or it is in the nature of possible potentiality. It is called intellectus in actu because it thinks whenever it wills without any further process of perception. it ~ay be pointed out that whether through the intermediary of someone else or through one's own self. or hal. There is first the stage of absolute. the rational soul. Aristotle had maintained that the heart was the seat of sensus communis and therefore of imagination and memory. . but Avicenna treats each as a separate faculty. it simply receives them. if not. or possible.' The theoretical faculty serves the purpose of receiving the impressions of the universal forms abstracted from matter. Its function includes also attention to everyday matters and to 'human arts.' present in every individual of the human species. Lastly. If the forms be already separate in themselves. It is the source of human behaviour and closely connected with moral considerations. when only the primary intelligibles which are the source and instrument of the secondary intelligibles have been acquired by the 'material potentiality. Sometimes. sensus communis.
' It is of the same genus as intellectus in habitu. There are two ways in which intelligible truths may be acquired. so th~t the forms that are in the active intelhgence are imprinted on hIS soul either all at once or very nearly so. This concludes the list of what constitute the different animal faculties which are served in their entirety by the vegetable faculties. Growth serves the reproductive. and by the imagination which accepts its combined or separate images. which is the ultimate goal. 89bII). And since the first principles of instruction are obtained through intuition.' If it is of some material thing. Sometimes it is done through intuition which is an act of the mind. and the nutritive serves them both. and ~ot all people share it. For beliefs based on authority possess no rational certainty. with recepuvity for inspiration from the active intel1ige~ce in all. the capacity is called intuition. and estimation is served by an anterior and a posterior faculty. The acquired intellect. because the material form is subject to certain states and conditions that do not belong to it as form. of which the reproductive is the first in rank. This is the highest stage of the disposition." And sometimes it is through instruction. Post. T" (A. i. but in their logical sequence and order. There is.a sunil eVrlToxta 6usn I}cuIsin mii. It enables him to make contact with the active intelligence without much effort or instruction until it seems as though he knows everything. Thu. because of their power and lofty nature.' and it represents the highest state of the faculties of man. and the highest are those who seem to have an intuition regarding all or most problems. . and this state of the material intelligence should be called the 'Divine Spirit. but far superi~r. and the anterior is the sum total of animal faculties. The four 'natural' faculties of digestion. however. Sensation cannot 141 I !.74. as will be seen. the lowest are those wholly devoid of intuition. And he does not accept them on authority. thin. • Najiit.s a man ~ay be ?f ~uch purity of soul and so closely in contact with the rational p~~cIp)es that he becomes 'ablaze' with intuition. it consists in perceiving the form abstracted to some extent from the matter. by imagination. dYX1vo.gs. the imagination is served by phantasia. and in the shortest time. by estimation and by the mind. is found to govern them all. 7} ~.e. Except that the kinds of separation or abstraction are different and its grades varied. it is pointed out that there is a difference between perception by sense. 'It appears that all perception is but the apprehension of the form of the perceived object. The practical intellect serves all of them and is in turn served by the faculty of estimation. and is in keeping with his views regarding the powers of a prophet and his mission in life. p. it may be said that ultimately all things are reduced to intuitions passed on b~ tho~ who ~~ve had them to their pupils. overflow into the imagination and be imitated by it in the form of sensible symbols and concrete words. and the abstraction is sometimes complete and at other times partial. In turn.AVICENNA PROBLEMS OF PSYCHOLOGY having immediate perception because of their more powerful potential intellects. The intellectus in habitu serves the intellectus in actu and is in turn served by the material intellect. rather the highest faculty of it. The appetitive is served by desire and anger. where it has more the sense of sagacity and quick-wittedness. and should preferably be called Divine Power. The faculty of representation is served by the appetitive which obeys it. Where a person can acquire knowledge. its application to the man endowed with prophetic insight has of course no Greek source. It is most probably Avicenna's own personal conception. Taking up the question of perception. and 'quick apprehension is the power of intuition. al-dhu!cii' fa huwa intuition is of Aristotelian origin. retention. from within himself. It is possible that some of the actions attributed to the 'Divine Intelligence' should. and these last by the motive faculty. 2. 'This is a kind of prophetic inspiration. assimilation and excretion are subservient to all these. Intuitive people vary in their capacltles.'> Although the idea of J Cf. The posterior conserves what is brought to it by estimation. a regular hierarchy among the faculties of man. which is itself served by the five senses.
For SInce every part of matter is potentially divisible ad znfinltum. It is not possible to suppose that the form is imprinted on some indivisible part. and from this imposSI. It would be no more an intellectual but a representational form.AVICENNA PROBLEMS OF PSYCHOLOGY disentangle form completely and divorce it from material accidents. Should they be exactly similar their totality could not be different from them except in quantity or numbers. and 143 t. which is not possible. which unless they have a definite position. A thing in space cannot be present or absent to something that is non-spatial.h~les foll. It is the intellectual faculty that perceives the forms as completely abstracted from matter as possible. but good and evil are in themselves immaterial entities and it is by accident that they are found in matter. And in that case the intelligible form would acquire some sort of figure or number. and have no particular and distinct position in a line as Aristotle . If the place of the intelligibies were in a body then the place of the forms would be in divisible or indivisible parts of that body. The subst~n:e in ~hich the intelligibies reside is not a body In Itsel~.. perception through the power of estimation. The same is true of the estimative faculty I w~ich is als~ depe~dent on a bodily organ as it perceives its objects only In particular images. one another. the genera and differentiae of a given form would also be infinite. the form cannot be divided into exactly similar parts. If. and a form imprinted upon it. nor ISIt constituted by a body. The faculty of estimation goes a little further.had shown. cannot become images at all. i . when the intelligible form is imprinted in matter. ~d wh~t is imprinted on a point is imprinted on a part of the line. p. colour and position cannot be found except in bodily matter. Thus the perception of particular forms occurs by means of a bodily organ. For instance shape. their distinctions from and their relations to. This is proved by the case of images. POInts are not combined into a line by being put together. Thus the presence of matter is needed if the form is to remain presented to it. * * * * Najat. The position of a point cannot be distinguished from the whole line. Additions and combinations take place only in the conceptual realm. The external senses perceive them in a way not completely divested of matter. genus and differentia do not have the coherence that they possess in a definition. Furthermore the particular is perceived only by what is material and the universal by what is immaterial and separate. And since a part cannot be the whole.ow.. however.a. 142 So far A vicenna is concerned with the powers and faculties of the vegetable. and perception through the power of the intellect. Fro~ that he proceeds to the nature of the soul.bl. before. . with the usual modifications that Avicenna is apt to introduce. although by accident they happen to be in matter. ~ I . nor can it retain the form in the absence of matter. In a manner it is a faculty found In the body. and the only alternatives are that it would be divided into similar or dissimilar parts. perception through the power of the imagination." This differentiation between the different forms of perception can also be traced to Alexander of Aphrodisias. for it receives the meanings which are immaterial. however. animal and human souls. because it cannot perceive without the forms being imprinted on a body in such a manner that both it and the body share the same imprint. because these forms are perceptible only if their matter is present. the form is imprinted on divisible matter then with the division of the matter it would be divided also. taking up the question whether such a thing as a soul exists at all. and a body cannot be present to what is incorporeal. The faculty of imagination also needs a physical organ. But the faculty of representation or imagination purifies the abstracted form to a higher degree. 2. On the other hand the division of form into dissimilar parts can only ~e . .~ivision into gene~a and differentiae. Furthermore. 'In this way differ perception through the power of sense. In the case of estimation the abstraction is relatively more complete than in the previous two forms of perception.79.
144 145 . nor between it and its special organ or the fact of its intellection. for there are those which are of the simplest. are potentially unlimited. 2. This has been proved. nor be the faculty of a body. nor its action be in a body or through a body. It is purely rationally that it knows its own self. this would mean that it is divisible. Should each have different relations with the form or with the different parts of the form. If with none. has in its completeness a unity of its own that is indivisible? How then can this unity as such be imprinted in what is divisible? Finally. • .. Let us suppose that it was otherwise. p. and does not sense itself. and they have neither genus nor differentia. the intelligiblesreside is a substance. nor its organ. which it does not. nor its act. Again. In that case the rational faculty could know itself either through the form of that organ. 2. it is the rational faculty that abstracts the intelligibles from all the different categories such as quantity. The second and third alternatives are obviously not possible. Avicenna says. and its act of intellection. that it is not possible for the percipient to perceive an organ which it uses as its own in its perception. Furthermore. If some parts have a relation and others have not. and the intelligible as it actually is at a certain moment of time. Through continued intellecti. And the abstraction is made in the mind. If all the parts have a relation with the form. then the whole cannot have any relation either. Whereas in the case of the rational faculty the contrary is true. as in the case of the sense-organs and the effect of excessivelight on human sight and thunderous noise on the hearing. And again not every intelligible can be divided into simpler intelligibles. some entirely different form. such as John Philoponus and Themistius. contrary to Aristotle.AVICENNA PROBLEMS OF PSYCHOLOGY their position will depend on some external element.'It is thus evident that the placein which . and what has the capacity to be unlimited cannot reside in a body. or through. its relation will be either with every part of that matter or with some parts or with none at all. constituting the principles for others. which have their source not only in Aristotle but in various commentators to his De Anima. And this is the reason why. place or position to be indicated or divided or subjected to similar processes. From this may be seen that the forms imprinted in matter are just the exterior forms of particular divisible entities. Najiit. l Najiit. nor a faculty tn a body liable to division and the impossibilities it involves. which cannot be maintained. and that which is called its organ. it gains in power and versatility. Avicenna says.onand thought and the consideration of complex matters. not a body. or through some numerically different form. and this shows that it cannot be in a body. and their parts. This is a proof. nothing intervenes between that faculty and its own self.1. p. but each is a complete intelligible in itself. therefore. nor its act of sensation. 2 Cf.'I These arguments. p. if a simple indivisible form were to exist in a divisible matter. are here restated with Avicenna's ability to reinterpret the views of his predecessors in his own way.' To take another argument.'3 Another proof is that those faculties that perceive through bodily organs weaken and ultimately corrupt those organs through the constant use of them. then they are no more parts. the activity of the rational faculty is not performed by means of a physical organ. it is establishedthat the supposed intelligibles which are for the reasonable faculty to conceive actually and in succession. and in like manner imagination does not imagine itself.92. that the entity which is capable of conceiving intelligibles be constituted ina body at all. And if it sometimes gets tired I • " . in Aristotle's Physics. so when it comes to exist as a form in the intellect. place and position. every part of which has an actual or potential relation with the other. Rahman: Amenna's Psychology. There remains only the possibility that it should know its own organ only and continuously. he maintains that 'sensation senses something external. it has no quantity.. nor its organ.93. 'It is not possible therefore. Moreover what is by definition composed of different parts. nor are they divisible in quantity or in meaning. then those that have not cannot enter as factors into the form. 101.cannot be dissimilar.
the members of the human body after reaching maturity. 295. By the fourth process. it waits till it finds the middle term of the syllogistic reasoning. These two activities are opposed to one another and mutually obstructive. and the essentials. sensation brings to it particulars from which four processes result. By the second process. The rational soul is assisted by the animal faculties in various ways. • Najiit. and another in relation to itself and its principles in the form of intellection. and anger makes one forget fear. fear. It is commonly known that thought of the inteIligibles makes one forget all these and that sensation in turn inhibits the soul from intellection. nor constituted by it. the soul seeks the relation between these individual universals such as negation and affirmation. Where the combination depending _onnegation and affirmation is self-evident. Its occupation with respect to the body is sensation. From these the soul obtains the fundamental concepts by using the imagination and the estimative faculty. it is kept away from the intelligible without the organ of intellection or the faculty itself being in any way impaired. In the supposed case of multiplicity. The cause of all this is the complete preoccupation of the soul with just one thing. where it is not. By the third process it acquires empirical premisses. and this results from an inherent inclination of its own. through an unbroken chain of transmission. and what happens to it after the death of the body? Human souls are all of the same species and significance. For instance.AVICENNA PROBLEMS OF PSYCHOLOGY -an interesting point-Cit is because the intellect seeks the help of the imagination which employs an organ liable to fatigue and so does not serve the mind. anger. appetite hinders anger. and the differences. * * * * But what exactly is the nature of the soul? Is it a unity. appetite. If they existed before the body. By the first process. the soul separates individual universals from the particulars by abstracting their concepts from the matter and material attachments and concomitants. p. it turns away from the other-it is very difficult for it to combine the two. it should be remembered that the soul has a twofold activity. imagination. and the accidentals. gradually begin to lose their strength. the whole relation being recognized as necessary and true in all cases. Not only does this dual activity of the soul produce this situation." Furthermore. whereas in most cases the rational faculty grows in capacity after that age. the difference among the souls could be according to their quiddity and 147 t t • 146 . Hence in cases of illness the activities of the mind do not stop entirely. and this in itself shows that it is not. the human soul acquires what has been generally accepted. All this goes to show that the soul is independent of the body and has activities of its own. one in relation to the body in the form of governance and control. As to the objection that the soul forgets its intelligibles and ceases activity in case of illness of the body and with old age. they are only diverted to something else. All this goes to show that the soul is not imprinted in the body. but occupation with even one of them produces exactly the same effect-fear keeps away hunger. If it were one of the bodily faculties it ought to follow the same course as the others. pain. The exact relation of the soul to the body is determined by its particular disposition to occupy itself with the governance and control of that body. as a basis for concept and assent. they must have been either single or multiple entities. or is it characterized by multiplicity.and by considering the common factors between them. it readily accepts it. sorrow. or consequences affirmatively or negatively conjoin with or disjoined from the antecedents. This process consists in finding through senseexperience a necessary predicate for a subject whether in the negative or affirmative. Once the soul is engrossed with the sensibles. so that if the soul becomes occupied with one. it is therefore impossible that they should have existed before the body. which is usually before or at the age of forty. It is impossible that they should have been either.
there could be no essential or numerical differentiation between them. The attempt to draw parallels between the assertions of A vicenna and those of Plotinus has produced some interesting results showing clearly the relation of one to the other. Though it sho. Its subsequent development. because their form is necessarily one. through the instrumentality of the body. This had been accepted by most subsequent philosophers. duly shaped by the different material elements in which they had resided. Once they have forsaken their bodies. or still more according to the causes which determined their material existence. Here A vicenna is characteristically influenced by a host of classical and Hellenistic philosophers. They must therefore differ according to the recipient of the form. This bond unites it to that body and keeps it away from all others different in nature. had become the subject of much study among the Islamic philosophers owing to its religious implications. or according to their relation to the elemerits. and to be attracted by it. and the enumerated categories do not apply to them in any way. however. Their differences could not be according to quiddity and form. And when there is no diversity. it is combined and transformed into an individual 'although that state and that relationship may remain obscure to us.AVICENNA PROBLEMS OF PSYCHOLOGY form.' The idea of J . and also the different forms and figures of their bodies. to control it. but contrary to him asserts that it is a separate substance capable of existing independently of the body. the souls cannot be different and of diverse kinds. It has been claimed that the earliest statements on the substantiality of the soul are found in his commentary on the De Anima of Aristotle.' And this body will be 'the domain and the instrument of the soul. J tI ' t• • Edit. 149 . Badawi: Aristu 'inti al-'Ar"". without. Avicenna had carefully studied the so-called Theology of Aristotle with its excerpts from the Enneads. In that case these two are either the parts of one and the same soul-and that would mean that what does not possess magnitude and extension is potentially divisible. there can be no multiplicity. agreeing with any of them on all points. He holds with Aristotle that the soul is the form and the quiddity of the body which controls and gives it its particular character. as well as by some of the assertions of religious dogma. two souls also come to be. remains bound to its own nature and is not conditioned by the body after it has completely left it. For when two bodies come into existence. and the different times of their coming into existence. however. problems of the soul. and a more thorough study of the correspondence may prove even more revealing. but to the vegetative and animal souls as well. according to the individual body to which that particular form and quiddity became attached. and had even written a commentary on it.' There is at the same time created in it a natural yearning to associate itself completely with that particular body-to use it. If they are absolutely separate entities. souls survive each 148 as a separate entity. Since the souls are pure and simple quiddities. which is equally absurd. as well as the works of Alexander. it is impossible that all human souls should have just one single essence in common. On the other hand. That is to say. or according to the time in which they became attached to the body. which is absurd-or a soul which is numerically one could be in two bodies at the same time.uld be noted that substance here is not strictly that of Aristotle's conception. its nature and existence. And when those peculiar dispositions which constitute the principle of its individualization are present in combination. In fact ever since the translation of the Phaedo into Arabic-a highly prized dialogueand the De Anima of Aristotle.' The soul thus achieves the principles on which its perfection is based. It thus stands that 'a soul comes into existence whenever a body suitable to it comes into existence. Because of this preoccupation the commentaries of Neo-Platonic authors who had tried to reconcile Plato and Aristotle on the subject of the soul were also translated. and that after separation it has an activity of its own regardless of its previous connections. whose writings on logic had been so much favoured by Avicenna. and Avicenna seems to attribute substantiality not only to the human soul.
before it or at least with it but not through it. he does not pursue. a 16UI. is it through some intermediary or directly? You will be in no need of an intermediary at such a time. are extremely remote from the vivid presentation we have here. you will find that you are unaware of everything about yourself except the fact that you are-that you exist. for how could this be when their existence is hidden from you unless they are exposed by dissection? Nor is what you perceive an assemblage of things in so far as it is an assemblage. Augustine also: In fact.'z This illuminating demonstration of the suspended man was quoted and copied by many Eastern and Western philosophers after Avicenna with occasional variations. With what do you perceive your self in such a state. So what you perceive is something other than these things which you do not perceive while you are perceiving your self. and do you ever cease to assert your own self? This could not happen to an alert observer. When you are in good health. and there is none. it would then have been proved in the understanding. or before or after it? And what is the percipient in you? Is it your senses. to I Is/'iiriit. But as a general principle. Therefore you perceive yourself without needing of any other faculty or medium.lose th~t flesh and have another. or some faculty in addition to your senses and corresponding to them? If it be your mind and a faculty besides your senses. viz. Thus that self which you perceive does not belong to the order of things that you perceive through the senses in any way whatever. Now that he has disposed of the faculties of the vegetative.. p. And if you imagine yourself to have been born from the very beginning with a healthy mind and disposition and then imagine that you are suspended in space for an instant. ~he Isharat contains an illustration. scholars are no more in doubt. and ponder. and even to the man in his sleep and to the drunkard in his intoxication the consciousness of his inner self is never absent from his mind even though he may not be aware of his whereabouts. Your self is thus not proved through it. who is your self definitely. 'It thus becomes clear that what you then perceive is not one of your members like a heart or a brain. yet the passages that have been cited fromPlotinus. or a movement or some other thing. Or IS 15° it what the sense of touch perceives? That could not be so either. and if it is part of what is understood from your act in so far as it is your act. such that you can comprehend matters properly. Avicenna says. It has been stated that it is of Neo-Platonic origin. 120. are you ever forgetful of your own existence.AVICENNA PROBLEMS OF PSYCHOLOGY the soul yearning for the body once it has itself come into existence as a separate entity is definitely of Plotinian origin. indeed I prove [the existence of] my self through the medium of my action. . Avicenna turns to what is perhaps the more interesting and important part of his psychology. you must prove from it an agent absolutely and not particularly. Do you deduce from all this that the perceived in you is what the sight perce~ves from your flesh? That could not be. . In the supposition of suspension in space we isolate you from all that. if thought is a form of activity. That it inspired the cogito ergo sum of Descartes. Let us look further. already introduced 10 the Shift. however. though related. which later became famous among mediaeval scholastics. or through what resembles the senses.. . his arguments in proof of the existence of t~e soul. In that case you will have to have an act to prove . and the perception takes place through your senses or some internal sense. you would still be what you are. or rather in a normal state. or your mind. If you prove that it is an act of yours and you do not prove yourself through it. if you prove your act as absolutely an act. Turn to yourself. animal and human souls and has demonstrated the nature of the human soul and its relation to the body. except for the external members of your body. in such a way that you do not see the parts of your body and the members of it do not to~ch one another. . and which you do not find necessary to make you what you are. because if you were to . but it should be remembered that there is a reference to the suspended man in St.. p." Avicenna continues. 'Perhaps you will say. the statement of Avicenna which. 1:10.
Nothing that necessarily comes into being together with the coming into existence of another thing need become corrupted with the corruption of the other.. its existencewould be purposeless.b. ThIS ISthe substance that pervades and rules the parts of the human bo~y as well. o~ mo~ion. Nor could the body possibly be the receptive and material cause of the soul. the connectI?n existing between that substance and these . and the latter does not take the form of the former whether in simplicity or composition. of protection in the general temperament of an animal is so~e~1Og else which you might call with justification the soul. The former does not logically entail the latter. There are cases where things originating from other things survive the latter's corruption provided their essences are not constituted in them. or of priority-a priority that is in essence and not 10 time. p. Moreover take the case of an animal. And the attachment or relationship must be one of coexistence. It moves by means of . for when the matter of a body suitable to be the instrument and the domain of the soul comes into being.all bodies would act in exactly the same way.then the corruption of one annuls the accidental relationship and does not corrupt the essence. Nor indeed could the body possibly be the formal or the final cause of the soul. Furthermore. something other than its corporeal body ~r e orgam. And an ani~al perceives by something other than that corporeal construction or the c~mbination of its parts. If it were to act through its essence. as was shown. whereas in fact we ~now that they a~e independent. And at the same time it prevents numerical multiplicity which. because the bringing into being for no special reason one soul and not another is impossible.c combination of it as may well be observed. cannot be ascribed to the soul. and neither of them would be an independent substance. then I Iskiiriit. or of pos~eri~rity. 12. which is sometimes an obstacle to perceptton. for it has been shown that the soul is in no way imprinted in the body. or you imagine. the body would be the cause of the soul and one of the four causes would apply. it is rather yourself 10 fact. Admittedly the body and the temperament could stand as an accessory cause to the soul. 'This substance is unique in you. It could not possibly be the efficient cause of the soul for it acts only through its faculties. the separate causes bring a particular soul into being. It would do so only if the essence of the first were constituted by and in the second.1. must be attached to it in some way.'1 And is the soul immortal? The soul does not die with the body nor does it suffer corruption in any way. It may therefore be concluded that the attachment of the soul to the body does not correspond to the attachment of an effect to some essential cause. and in nature there is nothing without a purpose. This is because every. This may somenmes be actually an obstacle to movement.AVICENNA PROBLEMS OF PSYCHOLOGY the effect that 'I prove my self by means of my act' is more comprehensive than that of the French philosopher. th . And it has ramificationsand faculties spread in your organs. And that is how the soul is said to originate from them. And if the attachment be acclde~tal and no~ 10 essence. The principle of the faculty of perception.ranches~st~ a ~ISposition in it so that it creates through ~epetlt10na c~rta1O 1Och~ation or rather a habit and nature. which master this controlling substance in the same manner as natural dispositions do. without a corresponding instrument through which to act and attain perfection. If the relation of the soul to the body be one of coexistence and the attachment be in essence and not accidentally. And if it were possible that an individual soul should come into being. then each is essentially correlated to the other. or you are 10 anger. or you desire. and.thing that is corrupted with the corruption of something else. one of your organs. and especially if what brings them into 153 . It is the reverse that is more comprehensible and likely. If the attachment of the soul to the body is such that it is posterior to it in existence. which does not apply here. And when you feel something through. whenever a new entity comes into being it is necessary that it should be preceded by matter fully disposed to receive it or to become related !o it.
'! If it has the potentiality of corruption it is impossible that it should possess the actuality of persistence also. 62. Thus for their existence the soul and the body are in no way interdependent on one another. And their relations also differ. p. which is the matter. I 155 . Every thing that is liable to corruption through some cause.• cannot in itself possess both the actuality of persistence and the potentiality of corruption. of Rahman. and it is only the time of its realization that it owes to the body. and the liability to one cannot be due to the other. it owes its being to some other thing. (I) one the possession of which gives it its actual existence. that the attachment of the soul to the body should be one of priority in existence. 188. In that case it could be temporal or essential. But if so. it would have to be through the destruction of the soul. it is not inseparably bound up with it in its very existence. possesses in itself the potentiality of corruption and. and the body is not its cause except by accident. trans. It is an entirely different substance. It is impossible to suppose that in one and the same thing there could be both corruption and persistence.AVICENNA PROBLEMS OF PSYCHOLOGY existence is different from what only prepares their coming into being together with itself. whereas in fact it dies through causes peculiar to itself and its composition. If the body died. From this it follows that its being is composed of two factors. It may further be said that in an absolute sense the two notions cannot exist together in something possessing a unitary essence. as a result of an essential priority. If. which is the form. There is another reason for the immortality of the soul.. and if it has the actuality to exist and persist. but in simple things whose 154 essence is separate. and not to the composite thing which is composed of this factor and some other. does not come from the body. It may thus be concluded that if the soul is absolutely simple and in no way divisible into matter and form. then. as has been repeatedly said. nor is it due to a faculty of it. Hence that potentiality belongs to something to which actual existence is only accidental and not of its essence. which is absurd. But what if the soul is composite? To answer that we have to go back to the substance which is its matter. The soul could not be attached to the body in time because it preceded it. As to those beings that suffer corruption. it cannot have the potentiality of corruption. To be sure the actuality of persistence is not the same as the potentiality of persistence. the one being a fact that happens to a body possessing the other. because the potentiality of persistence is something to be found in the very substance of the thing. one being correlated with the notion of corruption and the other with that of persistence. then our present discourse is devoted to this factor •. The two may exist jointly in composite things and in simple things that are constituted in the composite. p. but in the matter which potentially admits of both contraries. Avicenna's Psychology. which here means the body. the actuality of persistence. then the body could neither exist nor die independently of it. And so the corruptible Najat. it will not admit of corruption. and the soul in its being can be in true relationship only with other principles that do not suffer change or corruption. it is the composite in them that is corruptible. because the two concepts are contrary to one another. or this substance and base will never cease to exist. Furthermore the potentiality' to corruption and persistence is not to be found in something that gives unity to a composite. Hence the substance of the soul does not contain the potentiality of corruption. And if it were attached to it in essence. namely.. And (2) one which attained this actual existence though in itself it had only the potentiality of it. they cannot. This goes to show that ultimately all forms of attachment between the soul and the body prove to be false. So it is clear that everything which is simple . And the soul. There remains the third possibility. Therefore it may not be said that the attachment between the two is such as to necessitate that the body should be prior to the soul and possess an essential causal priority. 'We say: either that matter will continue to be divisible and so the same analysis will go on being applied to it and we shall then have a regress ad infinitum. before that occurs.
as also is the view that the soul is not imprinted. there is a happy combination of the best of both Aristotle and Plotinus. that souls come into being-and they are . They are to be found in a fragmentary and perhaps elementary form in Neo-Platonic writings that had been rendered into Arabic. And again. different actions might proceed from the same faculty or different faculties might become confused with one another. and were therefore available to Avicenna. and at the same time the potentiality that these forms may cease to persist in them. Islamic psychology found Neo-Platonic conceptions with regard to the soul and its nature highly congenial particularly in what may be called its spiritual aspects. on the body as form is in matter. with?ut the n~ed of a temperament and suitability in the body requirIng a particular soul to govern and control it. there would be no essential cause for multiformity. Of course these faculties interact and influence each other. With them the potentiality of corruption is something that is found in their matter and not in their actual substance. applies only to those things whose being is composed of matter and form.AVICENNA PROBLEMS OF PSYCHOLOGY composite has neither the potentiality to persist nor to suffer corruption. As with the theory of emanation. If these faculties did not unite into a greater whole. Avicenna could not entertain the idea of the transmigration of the soul. I Avicenna's Psychology. N?w if it be supposed that one soul can migrate Into several bodies each of which requires for its existence. Contrary to Plato and in agreement with Aristotle he rejected what to any Muslim was an abhorrent notion. These arguments in proof of the immortality of the soul are not of Aristotelian origin. and therefore already has. and this applies to all and not only to ~ome bodies. For Avicenna as for Aristotle. And the condition that everything that has come to be should suffer some form of corruption on account of the finitude of the potentialities of persistence and corruption in it. From all this it becomes evident that the soul does not suffer corruption at all. In their matter there would be the potentiality that their forms may persist in them. On the contrary embedded in his own distinctive line of thought. There remains the case of the simple entities that are constituted in matter. which is something that it acquires. while the matter either has persistence without its being due to the potentiality that can give it the capacity to persist. a separate soul. And consequently transmigration cannot take place in any manner. but that it controls and governs it in such a way that it is conscious of the body and the body is in turn influenced by it. If we were to suppose that the soul exists already and it just happens that a body comes into existence at the same time and the two somehow combine. when bodies are prepared to receive them. but they do not change with the other's 157 156 . or it has persistence through that potentiality. Nor is the influence of Hellenistic commentators altogether absent. and It IS this readiness of the body that necessitates their emanation from the separate causes. 1952.In endless n~~ber-:-<>nly. and sensation and anger and each of the others had a principle of its own. there would then be two souls in one and the same body at the same time. only an accidental one. is to be found in Plotinus. which is absurd. If that is the case then every body requires a special soul to itself suitable to its elements. It 'has been. and it has been learnt that essential causes are prior to accidental ones. made clear. This prevents the possibility of a second soul having exactly the same relationship to it. In his interesting works Dr Rahman has pointed out that the idea that destruction is the fate of composite substances only. But that does not mean that Avicenna deserts Aristotle completely. the soul is a single unity and not as Plato had taught a compound of three 'kinds.' The soul is one entity with many faculties. as some suppose. it has been maintained that the relationship between the soul and the body is not such that the soul is imprinted in the body. Oxford. Obviously this cannot happen by accident or chance. but does not have the potentiality of corruption. and that the soul being by nature simple and incorporeal is not liable to corruption. he says. nor both together.
He wants to attribute to i~dividual senses the knowledge both of their objects and of their own acts.mu~h argument. the nearer they approach a resemblance to the heavenly bodies and to tha~ ~xte?t they deserve to receive an animating force from the ongmatmg separate principle. in saying that there is no sixth sense which possesses self-consciousness •.is s~ul should necessarily be attached to the first organ m which life begins. And the first thing joined to the body cannot be some thing posterior to this.e. But the more recent interpreters •. It could not be the totality for obviously his hands and feet could have nothing to do with it. The faculty of anger does not perceive and that of perception does not become angry. What then of the all-embracing unity of the soul? It must be understood that among elemental bodies their absolute contrariness prevents them from receiving life. which has no opp~site. 158 159 . This unitary thing could be a man's body or his soul. 'This opinion of the philosopher' (i. because there would then be no one thing that sensed and consequently became angry. however. Here emerges the idea of self-consciousness and the existence of a ~ersonal ego through which the unity of experience can be explained. and ... like some of Aristotle's Hellenistic commentat. nor could it be just two.acts ~~ the senses: . the more capable of life they become. it is false to attribute self-consciousness to sensation itself.AVICENNA PROBLEMS OF PSYCHOLOGY change. Th... A passage m John Phtloponus throws some light on what seems to have ?een the ~ubjec~ Of. If it were his body it would either be the totality of his organs or some of them. We agree . nor two of them. Avicenna says. Nor indeed could it be one single organ w?ich. The uniting substance can only be the soul or the body inasmuch as it possesses a soul.. Plutarch holds that it is a function of the rational soul to know the .. and it must have a facul~ of combining both sensations. they receive a substance which in some ways is similar to ~he separate substance. perception and anger. which really means the same thing as the soul. Sensation having perceived colour must at all events reflect upon itself .o not possess the rational faculty.. Will and cholce--but besides these. And there are the vegetative and the perceptive in the animals. and animals d.. What becomes angry is that thing to which senseperception transmits its sensation.. and to the sensus communis the knowledge of objects and the knowledge of their acts as well. 'We.. and so it is impossible that an organ should be al!ve without a psychical faculty attached to it. If it thus reflects upon itself it belongs to the kind of separate activity. for the activity of each is special to the function that it performs.. Alexander .' But there are vegetative faculties in the plants. Hence the organ to which this psychical faculty has to be attached must be the heart. 'is contrary to that of the divine Plato.. would be the baSIS of both functions.. one sensing and the other becoming angry. what was said to originate in them only through the external substance may be now said to originate through both. 0p1~10n. Aristotle). just as the heavenly substances had received it and become attached to it. Here Avicenna. and plants do not possess the perceptive and rational faculties. What happens is that all the faculties bring what they receive to one unifying and controlling centre. For according to them the ra~o~al s~ul has n?t only five facultieS-intellect.. That thing cannot be the totality of our bodily organs.. The more the! are able to break that contrariness and approach the mean. This shows that each of these 1S a separate faculty by itself having no connection with the others. nor just one. And when they reach the limit beyond which it is impossible to approach the mean any n~arer and to reduce the contrary extremes any further.. goes b~yond what was envisaged by the Stagirite. also a sixth faculty WhlC~ they add to the rational soul and which they call the attentive faculty . attributes to the five senses the knowledge of their objects only. the principle of all the faculti:s. according to those who hold this view.. Once the elemental bodies have received this substance. The nearer they get to the mean.• say that It IS the function of the attentive part of the rational soul to know the acts of the senses.. re~son.ors. say about this that Aristotle s view 1Swrong .
In a similar fashion there is some power that emanates from this active inte~lec~and extends to the objects of imagination which are potential tnt~lligibles to make them actually so.A thing does not change from potentiality to actuality all by Itself ~ut through something that produces that. m Just the same way this substance is in ~tself. and tran~form~ the poten."in itself.. and whIch IS the cause of all potential intellects becoming act~al i~tell~cts..mu~t halt at some thing which is in essence an intellect. and the imagination also is called in relation to it another passive intellect. During sleep a man's imaginative faculty is more active than when he is awake because it is not overwhelmed by the external senses.. especially when it is in itself abstract and not pr~sen~ thr~ugh the act~o~ of something else. ~gain. And just as the sun IS by Itself an object I cr. Rahman: Avicenna's Psychology. ~he r~lation of the active intellect to our souls which are potentIally intellect. and which alone is sufficient to bring this about. One is when it is itself occupied With t. The significance and the function he gives them are quite different if not altogether original."al). In. and to the i~telligibles which are potential intelli~ibles.forms. and to the colours which are potentially perceptible. in relation to the potential intellects that pass ~rough It into actuality. For him they had to conform to the general system which he was attempting to build. dreams are the work of the imagination. The intellect that comes between the active and the passive is called the acquired intellect. resu~t.The essence of this thing undoubtedly possesses th~se . Here then is an important distinction between the intellect the intelligible. of s~ght and the agen~y ~hich makes what is a potential object of SIght actually so.i~telli~ble and an agency which transforms all potential intelligibles into actual ones. and is therefore incorporeal and eternal. and adopts the Neo-Platonic doctrine of emanation. i~ ~s the relation of the sun to our eyes which are potential perCIpIents.ltk~ manner the material intellect is called in relation to It a paSSIveintellect. There remains to be considered the element that gives actuality to a potential human intellect. p. 160 III..ateti~ idea that the intellect and the object of its intellection are identical. And the sensus communis also cannot come to its aid since it is busy with the external senses. and the actuahty conferred consists of the forms of the tntelhglbles. This thing is the acnve intelligence. If it were a potential intellect It would mean a regression ad infinitum. The other condition is that of the soul when employing the imagination in its intellectual activities either to construct together with the sensus communis concrete forms or.AVICENNA PROBLEMS OF PSYCHOLOGY also to a separate substance. For when light falls. somewhat similar statements may be found by Hellenistic commentators and by Farabi. In two conditi~ns the soul di~erts the imagination from the perfo~ance of Its proper function. In this A vicenna ~ejects ~e Perip. but none correspond exactly to what A vicenna envisages even where the terms used are the same. they become actually . Here then IS something that from its u~n substance ?rant~ ~o the human soul and imprints upon it the forms of the [nrelligibles.perceptt~le and the eye becomes an actual percipient.he external senses and devotes the image-forming power to their use rather than to that of the imaginative faculty which as a result becomes involved in other than its proper function. This thing IS~al!ed. The theoretical faculty i? ma~ emerges from a potential to an actual ~tate through ~he dlu~l1nating action of a substance that has this effect upon It. on the potential objects of sight. to discourage it from imagining things that do not F 161 . But one thing that is in itself intelligible is an intellect in essence. an active intellect (al-'aql al-fo. a?d is therefore an intellect in itself. and the act of intellection." It has been pointed out in this connection that the Stoics were the first to use the word 'ego' in a technical sense. which was to become prevalent among all Islamic thinkers after hi~. which is absurd .tlal into an actual intellect. and It IS actually eternally intelligible as well as intelligent. for it is the form separated from matter. The regression . But what of dreams in Avicenna's system? In his view as in that of Aristotle.
It opens in the diffident language of a youthful aspirant seeking recognition and patronage. and that it must have come from some other source . But then I SlUfii.> It has been claimed.M. 162. very litt~eto chan~e. Pro 47b:13) mutuwalrlUm. It IS remarkable for the fact that in all that he wrote on psychology afterwards. that actually all the 'internal senses' of which A vicenna speaks are differentiations or rather specifications of the Aristotelian pkantasia. And yet the fact that he already discusses it in this very early book written when hardly twenty years of age. Averroes and Ghazali may therefore have been right in .'TJifJ~ (Top. Berm. i.G. mro). makes it unlikely that they are right. the imagination finds an opporturuty to grow in intensity and to engage the image-forming power ~d make use of it. 64alo) tann 3 cr. it becomes disengage~ from such preoccupations and impediments as in sleep.hTt}). giving each a significance not envisaged by the Stagirite himself. Notice might also be taken of a very sho~ treat!se on the subject.D. and the image thereby produced ~allson the sensus communis. ISJaI6) wahm." To animals he attributes an estimative faculty (wakm and sometimes {ann) which the Latin Scholastics translated as aestimatio. . when the soul ceases to employ the min~ and make fine distinctions. 83. (Soplr. 04a:13) al-tann.y'Il1107]TD!. Cairo. belongs I think only to man. . 3. the Najat and the Iskarat. For it may be supposed that he was then too young for original contributions in the field of what was a purely theoretical psychology. and Van Dyke. however.yo~a (Categ. Rahman: Ope cit. Attempts to ascertain the correct Greek equivalents of the terms wakm and {ann have caused sharp controversy. and Dr Rahman may be justified in believing that it is a subdivision of pkantasia.. • t/>avrarrla cr.. It is addresse~ to. 13:1S A. p. when himself just a young physician of promise. Edit. or during the illness of the body. Averroes and Ghazali both asserted that this was a non-Aristotelian faculty invented by Avicenna himself. 187S. a conscious r effort to reproduce what has gone out of memory. • • • • The foregoing account is based on what A vicenna wrote ~n psychology in the Skifo.the Prince of Bukhara. Proc.e.. but recollection. Later he did alter his views on two points. p. Landauer.' This may well be so when it is remembered that in more than one place in his philosophical system. His conception was based principally on the De Anrma of Aristotle though it included matters not to be found there. he had.'TJifJ" (A. because the available materials have not yet been studied. I6Sb:1S) wahm. and that the so-called estimative faculty is one form of imagination or 'an operation subsidiary to imagination. cr. and as a result weakening its-powers of representation.thinking that the estimative faculty was a nonAristotelian innovation of A vicenna. In the early workl common sense and memory are considered as one and the ~ame f~~lty. then deve~ops int~ a cle~r exposition of his conception of the soul and Its faculties. Ope cit. NiiQ ibn Mansar. This is the power by which the sheep senses that a wolf is to be avoided as an object of fear. 163 . and may quite possibly be the very earliest. A vicenna has taken an Aristotelian idea and divided it into subsidiary parts. whom he had been invited to treat for an illness. (A.3 and with some good arguments.H. Moreover he was at first inclined to attribute the power of recollection to 'animals then later changed to the belief that 'memory may be found in' all animals. because it is certainly one of the earhest things he ever wrote. Rahman. When. The 'combination of the two powers adds still more to their activity. and the former took strong exception to it. whereas in the Skifo and the Najat they are entirely distinct. and the object is seen as though It were externally existent. .AVICENNA PROBLEMS OF PSYCHOLOGY conform with actual objects. &J~a (P. in spite of some additions. Z. :1Ia33) aI-tawahlrum.
In our material world. It comprehends meamng and intention in objects. and which the translators used long before him. Imagination knows an object n?t as matter or as pr. as well as different bodies. with the particular form that he possesses. faculty which perceives such notions as pleasure and pam. and gave himself every liberty. are never remembered in themselves as such. the estimative faculty plays its part in the grades of abstraction.only when the form is present in the matter of that object. 165 . or just' a term. This was Avicenna's attempt to explain knowledge when coming from sensation and when abstracted and universalized by the intellect. He was. but in the image of the matenal attachments that 1t has acquired. This is done through the faculties of imagination and estimation. Now if the matter and the form be the same. and that the Active Intelligence. In the next stage comes imagination. but matter with a particular and predetermined disposition. Knowledge comes by means of bridging the gap between the material forms of sensible objects and the abstract forms of intelligibles. on the other hand. and what is it that gives them their particular individuality? It has been shown that the basis of all beings in our world is matter. then why can they be so different -from one another. According to Avicenna. Intellect was the recipient of universal forms and sensation the recipient of individual forms as present in matter. Avicenna argued. not of separate specimens of any species. 164 The principle of individuation by matter entailed some difficulties. in his view. Avicenna I De Mem. Sensation perce1ves forms embedded in matter. The images that it forms are. It could not possibly take place without the presence of matter. In.. 4Soa1O-14. It arrives at knowledge of an object by perceiving its form and this it can do . which it has been shown to have. it is quite evident that the species man. how and why do they individualize? This problem arises in both the ontological as well as the psychological field-individualization among different species of being in general. And the same may be said of other species. just the opposite is true. however. The principle is matter. t~e first stage is sensation. In the final act reason comes to know things that have either been abstracted into pure form or that it abstracts itself completely and takes in their ultimate universality. like Averroes. This. and the means by which one led to theother-questions to which Aristotelian theory gave. is only an explanation of the existence of different species. which sees goodness and badness in the individual objects that ha~e been first sensed and then imagined. therefore. and among individuals of the human species. is represented by more than one individual. not material images ev~n though they may be fashioned after the pattern of matenal objects. no servile commentator. the difference between the two. I Intelligibles. and consequently differentiation is entirely on the basis of form and quiddity which determine species. The next process is taken up by the esti~ative. .AVICENNA PROBLEMS OF PSYCHOLOGY it would riot need a Greek equivalent. they must come from the matter which thereby permits that multiplicity of forms impossible among pure intelligences. In the world of pure intelligences. no satisfactory answer. could not come from the form. have the same matter in common between them. But-and here comes the difficulty-if different individuals. In this world of generation and corruption. the acqu~sition of knowledge. bestows upon this matter a form to produce the different species. The individual differences. In any case Avicenna was capable of taking an idea. consequently. and making it entirely his own. form is the essential thing. since religion asserted that their souls survived individually. which can act without the presence of the physical object itself. and maintained their individual human identity . in a certain predetermined state which make it 'merit' (yastaJiq) one form to the exclusion of another. and also have the same form in common. Avicenna says in agreement with Aristotle.esent in matter. as the Giver of Forms. and thereby carries the abstraction one stage further. or a suggestion. he had said.: Aristotle had denied intellectual memory. It was important to know why individual persons differed among themselves.
With tears welling forth from its eyes without pausing or rest. His conception. and strong is the cage whereby It is held from seeking the lofty and spacious sky. until her star Setteth at length in a place from its rising far. was that there are two retentive faculties in the human soul. Until. p. Till. That the things that it hath not heard it thus may learn. and slowly grew used to this desolate waste. Vol. unwillingly went. 166 . heavenly Dove.. to the C of its centre. (For even the lowliest being doth knowledge raise. were its haunts and its troth In the heavenly gardens and groves. Thick nets detain it. It is like to be still more unwilling thy body to leave. and from it the inteIligibles start to emanate again as they had done before. So 'tis she whom Fate doth plunder. the second. There is no special faculty for the retention of intelligibles as such. Browne of Cambridge. and 10. p. It carols with joy. 2. And 'tis time for it to return to its ampler sphere. ineffable.AVICENNA PROBLEMS OF PSYCHOLOGY asserts the same view in various places. aware of all hidden things In the universe. 137. as though it ne'er had been. as the representative faculty. as the faculty of conservation. I la-I I. I It weeps. pp. And with plaintive mourning it broodeth like one bereft O'er such trace of its home as the fourfold winds have left. 'Twas concealed from the eyes of all those who its nature would ken. G. glorious. That exalted. Now why from its perch on high was it cast like this To the lowest Nadir's gloomy and drear abyss? Was it God who cast it forth for some purpose wise. And to earth. * * * * /sMriit. Concealed from the keenest seeker's inquiring eyes? Then is its descent a discipline wise but stem. a/hid. Until. and yet. and is ever apparent to men. when it entered the D of its downward Descent. 3 Lit. and would not be tamed in haste. stored images. And when the soul wishes to contemplate the intelligibles. it was hurled Midst the sign-posts and ruined abodes of this desolate world.» but supports it by means of the Nee-Platonic theory of the emanation of intelligibles directly from the Active Intelligence.s We may close this chapter with his celebrated Ode on the Soul as done into English by the late Prof. The first. when the hour of its homeward flight draws near. Like a gleam of lightning which over the meadows shone. in a moment is gone. as I ween.) And so it returneth. Hut. when it thinks of its home and the peace it possessed. which to leave it was loath. And. of Persia. Yet it wears not a veil. for the veil is raised. It resisted and struggled. though it grieve. Unwilling it sought thee and joined thee. On a lofty height doth it warble its songs of praise. what happens is that it reunites itself with the Active Intelligence.3 It descended upon thee from out of the regions above. and it spies Such things as cannot be witnessed by waking eyes. which was to have a great influence on the mediaeval scholastics. 179. stored meanings or intentions. forgotten at length. Yet it joined thee. E. while no stain to its garmentclings. The eye(I) oflnfirmity smote it.
that where there is a better there must needs also be a best. he set out to devel0.' It is direct and intuitive. namely. As to Averroes. for Aristotle. he is 'beyond activity. Nothing remaining from the pen of Kindi. in accordance with the tenets of his Faith. Avicenna's devotion to the principles of rational thought always predominated. Ghazali's chief concern was to emphasize the limitations of reason.h~_Q~ncol1<:eption the Deity. nor in principle. strictly one. nor in definition. and an agreement in essentials more consistently attempted. nor an intelligible form in an intelligible matter. and to call men to the higher regions of religious experience. nor the matter of a body. life and mind.' Hence as a transcendental being God is. and who. to which Avicenna was anxious to conform and be faithful as far as he possibly could. Of Avicenna's successors. yet he was deeply animated by the desire to see both disciplines brought into harmony. by what amounts to a form of the ontological argument. and does not flow from his knowledge. all-powerful. But his activity is only mental. He may never have failed to attack the theologians when he thought they were in error. Go~~has no knowledge of the universe a~l!ngus. but that need not cast doubt on his protestations of religious faith even though his faith is different from the orthodox. yet he captured and expressed the spirit of his age. of God. 'is not a body. though himself I fa pnilosopiUe. requires us to qualify that statement. Those who have tried to attribute to Aristotle a theistic view of the universe have failed to win general agreement. he has only himself as the object of his thought. and confined himself to a re-statement of the position as he found it. He may have refused to submit to tradition and unquestioned dogma.' He is a Necessary Being in essence as well as in all other respects. nor an intelligible matter for an intelligible form. He is not divisible. He is complete in himself. The Neo-Platonic conception coloured much of Islamic thought. Cf. nor of the evil thatthere may be in it. God. and (accord. moved everything by inspiring love and desire in them. beyond intellect and intellection. and no state in him is to be 'awaited. all-controlling Creator of heaven and earth. to insist on the necessity for dogma. He could not be F* I~ 168 .R. the final cause. and his knowledge 'involves no transition from premises to conclusion. His influence is O:()t irect. and nothing from the more extensive writings of Hirabi that we possess. than in the system of Avicenna. he is One. It would d indeed detract from his perfection were he to be interested in this world of ours. among others.PROBLEMS OF RELIGION CHAPTER VI PROBLEMS OF RELIGION NOWHERE in Islamic philosophy are the problems of reason and revelation better contrasted. but he realized that the mind does not succeed in proving the truth of things in every case. he says. the First. and as the Good. and many others of which he was aware. was an ever-living being whose influence radiates throughout the universe. This Being whose existence he proves. is form and actuality. but out of sincere desire. He may not have succeeded completely.' and. even when applying himself directly to the issue in question' he had nothing new to contribute. not asa matter of policy or convenience asTomenave~ thought. neither in quantity. nor the form of one. Gauthier: La TMorie a'lIm Roclui sure /es Rapports ae fa Religion et de unmoved. As the One he is the first cause.' Finally. The One is 'beyond substance. there was the religious beliefin God as the all-knowing. For Plotinus God was the One. And between -these hardly reconcilable views. pace Aristotle. He is transcendent as well as immanent in the world of the soul.ing to Plato) the Good.
43-'7. there remains nothing incomplete or lacking in him to be awaited -neither will. is pure Good. for in that case they would not be intellected but sensed or imagined and that would be a defect for him.' It is as a separate and abstracted entity that he is an intelligence. Not the smallest atom in the heavens or on earth is hidden from him 'and this is one of the miracles the imagination of which requires a subtle nature. since the reality of every thing is the particularity of its existence which can be proved to belong to it. nor knowledge. he intellects and he is intelligible. This could not apply to what is in essencea possible being. p. By the very fact that he is in essence necessary he becomes a species apart and particular to himself. and therefore he has none like him. God is 'in essence an intelligence.' Then he feels constrained to quote a Qur'anic passage and to assert that He is at the same time aware. 2. though that knowledge is only 'in a general way. And as a species in himself he is One because he is complete in his existence. he who is a necessary being in his essence. pure goodness. This brings us to the nature of God's knowledge of things. and there is nothing more true than him. it is perceived through the senses or the imagination or the mind and the intellectual perception is the highest of them all. for 'there can be no beauty I cr. God as a source of help becomes a source of Good and free of all defect or evil. is intelligible in essence.' Thus Avicenna departs from Aristotle in asserting that God does have knowledge of the world. is pure Good and pure Perfection. he cannot think of them as sometimes existent and at other times non-existent. Najat. God does not think of things from perception of those things directly. to the extent of a single atom. and everything that is possible has already become necessary in him. nor nature. He could not be both at the same time. and he is intelligible because everything that is in essence separate from matter and all the accidents. God possesses the purest of beauty and light. 170 or light more than in a state where the quiddity is pure intellectuality. because he is indivisible and because in the scale of existence his position is that of the necessity of existence which he does not share with any other. pp. Najat. and evil does not exist in essence. perfection and light and who 'intellects' himself with full intellection. So the Necessary Being who possesses the utmost beauty. As compared with the sensual.view~There is in fact no experience to be compared to it. Furthermore. or of any undesirable state of it. And if he is necessary in every way.AVICENNA PROBLEMS OF RELIGION a necessary being in one sense and a possible being in another. intellectual perception is much !he_~rrOllger.:19. because his definition applies only to himself. Avicenna realizes the difficulty of his position and therefore proceeds to explain further. and it is superior as regards the objects that it perceives and the manner of doing so and the purpose which it lias~ln. unblemished by any form of defect. because that would involve contradiction. of all that happens in heaven and earth. considering that the subject and the object of intellection are in reality one and the same in this case. . 'Existence is a goodness.t God as a necessary being in essence is pure truth. nor any of his attributes.r When the Necessary Being intellects his essence and the fact I cr. The Good is what every being keenly desires in order to perfect its existence. 171 2. and the perfection of existence is the goodness of existence: Thus a being that does not suffer any evil in the form of the absence of a substance. it is a condition of perfection. it is in consideration of the fact that he is aware that his essence has a separate entity that he 'intellects'. no associate and no contrary. 'his essence would be to himself the greatest lover and beloved' and the greatest source of pleasure. Good in the sense of useful and profitable is only with the object of attaining perfection in things.' Every suitable beauty and perceptible good is desired and loved. The Necessary Being 'intellects every thing in a general way' and yet he is not ignorant of any particular thing. his intellection is not of changeable things with their constant changes in so far as they are individually changeable in time.
For you it is necessary to know a whole series of causes and effects in the movement of the heavenly bodies in order to know the circumstancesof just one eclipse. The other attributes have this specifiedexistence with some additional quality affirmed or denied. When it is said that he is the first. It is the action and interaction of these causes that bring about particular events and matters. p. his knowledge and conse. the implication is that his existence is beyond the possibility of mixing with matter or with anything related to it. It is a principle in itself. he is intelligible. This is because he could not know the original causes and yet be unaware 'of their results. and supplicated in times of trouble. In the case of God his time. when emanating from him. and therefore knows necessarily the effects that they produce and the time involved between them-and their recurrence.' And the power that he has. it is in relation to all other things.-) as well as postI Cf. God entertains no such purpose. This leads to what became the subject of heated discussion among theologians of all shades of opinion. We love and seek the good. even though they may have occurred to a single person at a particular time and under special conditions.. as pure intellect. or in definition. is due to the fact that his essence intellects every single thing. 173 . When it is said that he is bountiful. is pre-eternal (aralv. and is bent on intellection. When it is said that he is sought as a refuge.~~J.1 In fact God's will is itself a bounty. in itself sufficient to produce results without any intermediary.. if you know the heavenly movements you can tell in a general way every eclipse or conjunction of the stars. And there is no single thing the existenceof which did not become in some way necessary through him. God. but God knows everything because he is the principle of everything. this will is not bound up with any specific consideration. is. without implying in any way multiplicity in essence. perceives and acts continuously. God only needs to think of things. the reason is that he is the principle of the order of the Good. he intellects the origin of the existent things that have proceeded from him. in essence. God contemplates his essence as well as the order of the Good pervading all things. and this leads to the knowledge of the world and 'the keys of what is hidden' from us.. and is not derived from any thing nor dependent on the existence of any thing. And by doing so. In emanating existence. the meaning is that his being. quently his judgement are eternal and all-embracing.the will of God does not differ from his knowledge. 159. Moreover. this means that his existence does not allow division in quantity.Qmesto be. and that intellection becomes the principle of all things. When said that he is One. When it is said that he is an essence or an immaterial substance. the movements and therefore the results. it is meant that he seeks nothing for himself. viz. or in association with other than himself. He knows the causes and therefore the effects. that order emanates from him to all existent things. and that becomes the cause and the starting-point of his acts and 172 the originof aIL!h. and 'powerful' denotes that the existence of all things proceeds from him. Yet your knowledge would be limited by your ability to make the proper calculations and by the fact that you are yourself a momentary being. it means that he is not in a subject. but only for a purpose. When it is said that he is an intellect. He who is the first cause knows full well the various causes and their application and working. moreover. When it is said that he is a living God. 'The knowledge that he has is exactly the will that he has. Islzarat. The first attribute of the Necessary Being is that he is and is existent. it is out of sheer bounty (jl1d). the attributes of God. The intelligible form that moves us. Hence God would be conscious of individual matters inasmuch as they are in principle general matters in their circumstances and nature. Life for us is perfected through perception and action-two different forces in themselves. and he possesses this form of pure intellectual will with no specific aim in view.AVICENNA PROBLEMS OF RELIGION that he is the principle of every existing being. As an illustration. and becomes the source of the concrete form that we reproduce in art.
then. and by means of which the different spheres including our sub-lunary world come into existence. and desirous of the working of such an order. creation is not altogether ex nihilo. not separately.> And in another place Avicenna says that providence is the all-encompassing knowledge of God about things. What of God's providence ('iniiyat) of which we are all in need. his essence and his existence are one. Nor do any of the categories of being apply to him. With these he brings together the necessary causes. • cr. and as a result of that contemplation it emanates from him to this world. He has no quiddity. The matter that constitutes the material cause must be there. he demonstrates all things. he loves and he is beloved. and his life is his power. How is that consummated? It takes two forms. is more direct. contemplates it in its highest conceivable form. And if he has no genus. There is necessity involved in the act. he has no differentia. The absence of one or the other renders an act of creation impossible of consummation. These are all united in him and act in unison. * * * * Shifii. as in the question of the attributes of God. p. These emanate from him. and how they should be that they may attain the best order. I/iiluyat.3 Hence his notion of providence is very general and rather abstract. Aristotle had no theory of divine providence nor of divine 175 174 . What is essential is that the two elements must be present. contrary to the views of the theologians to whom in any case the theory of emanation was also unacceptable. Thus God could not have will and wished not to create the world. but in his characteristic manner gave them a purely rational interpretation. He rejoices in all that emanates from him. It was seen how reflection or contemplation on the part of God makes what is possible in essence necessary for all possible beings. This knowledge of the proper order of existence becomes the source from which good emanates to everything. The efficientcause may be a necessitating will or nature or instrument. Iskarat. and. and he himself is pure existence. This may be called divine providence. Avicenna would not deny any of them. being the source of all good and perfection in so far as it is possible. Creation is one of the acts of God most emphatically stressed by religion. as dogma asserts. It was probably for this reason that the Christian scholastics of the thirteenth century accused him of having denied divine providence completely. In all cases it requires that God should be living and powerful and should possess a knowledge and a will of his own. which is specifiedby distinct terms. The other more active form of creation. There must be an agent and there must be matter. and the evidences of which we see all around us? God. and hence has no definition. Here. knowing himself and the existence of an order of the Good. for genus defines the nature of what is. Avicenna attempts a reconciliation between purely intellectual conceptions and the more concrete ideas of tradition and religious dogma. As a pure substance. for every being that has quiddity besides existence is caused. I8S. and through the action and interaction of the efficient cause and the material or receptive cause. Actually his conception is in full accord with the principles of his metaphysics. 3 cr. unlike all possible beings. he is simple. and the material cause may be a particular disposition that did not exist previously. creation does not depend merely on the wish and will of God at one specified moment and not at another. Moreover. One is through the process of emanation which is inherent in the Necessary Being. Ilaluyyat. It necessarily takes place in consequence of His will and nature. He is love. and he is the most happy of beings. The attributes to which theologians attached such importance were numerous. The world could not have failed to proceed from Him.I Since he has no quiddity. he has no genus. His knowledge is his will. In other words.AVICENNA PROBLEMS OF RELIGION eternal (abaazy). He cannot therefore be demonstrated. I and God's intervention through divine providence explained many a perplexity. Skifii. creation takes place.
The time of creation was the most important issue. If it is for creation itself. designed or brought into being what did not exist before. but necessary through some something else. p. 411 If. it may be supposed that once the act has taken place. and after creation does he continue to keep some sort of relation with his creatures. and who or what determines the time of creation? Avicenna did not take the traditional view on these matters and thereby incurred the displeasure of the theologians. Architects often die leaving their buildings intact after them. • so that ibdii' is of a higher order than takwin or ~diith.to show that there can be no time more suitable than another for creation.1. I24a30) badtn. or the time for it suddenly arrived.iyya. There was the case of ibdii' which appears in some verbal forms for the equivalent of various Greek words in the Arabic translation of the Theology and therefore of Plotinian texts. How could one distinguish when preexistence.then kawn or takwin. 1393a30) kkalq. and the latter did not always define them in the same way. There were also some doctrinal questions involved in the problem of creation. In either case they are necessary through sOl_De ther agency and not in their o I [sniiriit. 3 'Yl:vea~ (Top. at what was the most suitable time. Risiilat al-Nairur. 153. it was after A viccnna that it became established in its specific sense. or some accident besides his will. between God and his creation there is no priority in time. Moreover. 9b3S) takWin. 'Yl:vea~ (Categ. 176 177 . Before that it was a purely religious word of Qur'anic origin. 147 If.I then ~adth or i~diith.r AVICENNA PROBLEMS OF RELIGION creation. khallJ to the natural beings ••• and takwin to the corruptible among them. There could be no purpose or profit when the existence or non-existence of a thing in no way affects him and would be the same for him. or that it was only at that moment that he felt puissant enough to do so? No. This latter class may be continuously necessary. In fact he had argued against the creation of the world. Should he disappear. as for instance: does God know what he creates. There is no question of compulsion or chance. and it took place at a fixed time. Then there was 1chal1J. and the Ash'arites said that the time was determined by God's own will only. Avicenna argues at Iength. and in what way does one time differ from another? Creation must be due to God's nature. They also came to mean one thing to the theologians and another to the Falasifo.'4 The purest and the most original act of God may be called an ibdii' because it is 'when from one thing existence is granted to another-an existence belonging to it only-without an intermediary. and A vicenna differentiated between them and considered that'ibdii' is special to the intelligence . In any case. The Mu'tazelite school of theologians said that the world was created I 7To£eiv (RAet.. be it matter or instrument or time • .•. if God be considered the agent or artificer who acted. • 7Tot7Ja~ (Top. pp. I24a30) kawn. are we to suppose that the moment for doing so just pleased him. and then the bodies. But the translators of his works had used in their Arabic renderings a number of religious terms for creation which gradually came to acquire somewhat different connotations. The way to answer this is to find out what exactly is meant by designing or bringing into effect. 4 Cf. his creation will continue to exist. S [sniiriit. Najiit. which was a period of non-existence.3 These were not always used in a specific sense. If the first beings are the intelligences. and though it may have been used by some Isma'ili authors.' 5 Kindi and Farabi had not given it the same connotation. began and when it ended. there is no more need for the agent or artificer. they are all distinct from the Necessary Being in that they came to be after not being. after which come the souls. Must we suppose that these are changeable and they actually changed when the suitable time for creation arrived? God creates either for the very act of creation or for some purpose or profit. or possible in themselves and in essence. God's disappearance could do no harm to the world nor injury to anyone. On another interpretation beings may be necessary in themselves and in their essence. or for a period of time. pp.
' and by that same power he comes into contact with the Active Intelligence. It is then that the material intelligence may be called the Divine Spirit. a man must rise to become the leader of men. and those necessary for only a certain period. the most noble in character. 'The matter that receives an entelechy or perfection like his. occurs in very rare temperaments. Tis'a Rasa'il." I cr.' • • • • The prophet and his role in society was a subject that Avicenna could not overlook in a system which though philosophical had to consider religious questions as well. as was seen. IlahIyyat. Najat. He who is endowed with the prophetic gift need not do so. cr. God did not have an absolutely free choice. To these is added what he receives through contact with the Active Intelligence. And in a human society men are bound to have constant association with one another. p. To dispense justice there must needs be laws and to lay down laws there must be a lawgiver. And to be chosen for that mission he must possess merits that others either do not have at all or have to a lesser extent than he. By an extraordinary capacity tor intuition. Surely those that are continuously necessary are the more general. though the more religious took strong exception to it. To be a lawgiver. The qualities of a prophet were perfectly human and in no way supernatural. These relations must be governed and directed so that justice may prevail. and devote his life and efforts to the problems of society. fellow-men. Avicenna arguesj? no one is happy entirely alone. his faculty of imagination would be so strong as to reach the point of perfection. 149-50. By these merits he must win the submission and support of his I . and could not appoint any man and make him the instrument of his divine dispensation. though a possible being in essence. and this is prophetic inspiration (ilham) which becomes transformed into revelation (w~y). pp. Shifa. Already in his psychology A vicenna had pointed out the lucidity of mind and unusual intellectual faculties that a prophet must possess. All others must seek 'the middle term of a syllogism' in their logical reasoning. a necessary being through the agency of what is always and for ever a necessary being in essence. and Pi Ithhat al-Nuhuwwat. Greek thought had nothing to contribute in this field. And presumably it is for this reason that he can use such vivid imagery and speak so effectively in metaphors and allegories. Isharat. Hence the relation or attachment (ta'alluq) of the Necessary Being with those that are caused (ma'liii) or that have been acted upon (maf'iil) is predominantly continuousonly in special circumstances is it temporary. devoted some attention to the question. the prophet acquires knowledge 'from within himself. He is thus a superior representative of the human species in his capacities. 178 179 . 303. The intense purity of his soul and his firm link with the Active Intelligence make him 'ablaze with intuition. yet his unequalled excellences were sufficient to make him a necessary and not a free choice. lliihIyyat. Farabi. This is the highest stage which man can reach. except that he is chosen. Shift. What kind of a man is a prophet. F urthermore. in what way does he differ from others. and the traditional teachings he could not accept in their entirety.°AVICENNA PROBLEMS OF RELIGION essence. Hence contrary to the general opinion. Najat.' The forms of the Active Intelligence become imprinted on his soul. authorized and inspired by God who makes his holy spirit descend upon him. and distinguished by godliness. perhaps because the theologians had elaborated a rather complicated theory about it. Tis' a Rasa'i/. Cf. Obviously this leader could not but be a human being like all the rest. Having gained these. just particular cases. it has to extend beyond the period of creation in order that it may continue to be. His successor in tum developed one of his own which seemed to satisfy his rational inclinations. And that being so. and it would then belong to the genus of intellectus in habitu. he can attend to their needs and apply the 'order of the Good' provided for them by God. p. and what is his mission in life? Man lives in a society. 303.
chose to stress the political and social aspects so prominently featured in Farabi. The religious teachings of the prophet are composed of these essentialsthat men should accept and those practices that they must follow. animal and personal acts. He must teach that there is a Creator who is one and powerful and whom man must obey because He has provided rewards and punishment for all human acts. Najat. He must speak in allegories and symbols. His descriptions of the hereafter must be full of imagery depicting eternal bliss or torment. These make I cr. To make them a permanent influence. This last makes men think of him. Of these are prayers and fasting and a pilgrimage to the home of the prophet. It takes two forms. and finds his grace through understanding-and be it noted that the recognition that Avicenna stresses is all intellectual-he is bound to think of the reality of creation. nor by means of the human tongue. and the emotional response drives him to worship the being he has come to accept as the 'Absolute Truth' and appeal to his unfailing loving-kindness. Mehren. Hence. but the impulse is the same. They who exerciseinward prayers. if not forces. for . and by doing so think of God who chose him. and chooses different means to express itself. and perceives him through his mind.' The outward is the one required by the religious law. 180 the soul turn to realms beyond the life it leads on earth. Ates. I cr. * * * * One of the practices that a prophet should enjoin people to observe is prayer. Death does not sever the bonds of love.' But it is the inward prayer that is the most real and elevating. Shifa. and that in turn inclines. When man knows God through reasoning. It is to the common man that he must address his exhortations-the person who is most in need of his help and guidance. there is a twofold process in prayer. They make It seek knowledge and perception and this timeless quest leads to worship. the importance of his mission that makes it 'necessary in God's own wisdom' to send him forth as a messenger and prophet. This moves him and makes him anxious and eager. the other is the inward and the 'real. It is a force that pervades all beingsj even the simple inanimate substances. mainly under the influence of Plato's Republic and Laws and Aristotle's Politics. like the angels who perceive without the need of senses and who ~nderstand without speech. man has a rational soul with activities ontsown that are far more elevated and noble. and they who partake of true worship do so through the love of God. Prayer is an act of knowledge as well as an act of gratitude to the Necessary Being. and of things that people value highly. whether it be sensuous love or the love of heavenly beings. It includes reading and kneeling and prostrating and has its usefulness because 'not all people can scale the heights of the mind. The Islamic conception of prophethood combined these three elements. Supplication to God is not through the members of the body. Fi Miihlyyat ai-Sal at. and the Falasifo. lSI . edit. It begins as a purely intellectual recognition and wonder which provokes an emotional response. ponder and speculate. al-'Ishq. a man to turn towards God. and.AVICENNA PROBLEMS OF RELIGION It is. It means beholding 'the Truth' with a pure heart and a self cleansed of earthly desires. The prophet must not enter into abstruse disquisitions on the nature of God because the vast majority do not understand such things. It takes different forms. The love of God extends throughout nature. Every living thing possesses an inherent love of the Absolute Good which in turn shines forth and illumines it. They are apt 'to rush into the street' and argue and quarrel and be kept away from their proper duties. Ft Mahiyyat . Among these are contemplation and reflection and the thought of Him who has fashioned the world and all that is found therein. a danger that his teachings be neglected or completely lost sight of in later ages. one is the outward and the ritualistic. however. This mission is political and social as well as religious. But what is prayerj" In contrast to his natural. behold God through the mind. There is. however. he must lay down religious practices. according to Avicenna's view. edit.
he completely disregards the resurrection of the body and dwells on the return (ma'ad) of the soul after its separation from the body. so also there is a death of the will and a natural death. and does not feel bound by the literal meaning of certain of the passages.:.) . and in partaking of the Good that emanates from God. in receiving the imprint of the form of the universal order of the intelligible. edit. that is in order that it should appeal to the ordinary man who is unable to appreciate the true significance of all that he reads. If it is full of imagery. It is in fact the release and the resurrection of I the soul that takes place. but he considers the language symbolic and metaphorical. Cf. It is. The soul must perceive the essence of perfection by deducing the unknown from the known. We need not sorrow because there is death. In lengthy expositions. He finds it idle to indulge in the formal exegesis associated with the different schools of theology. His interpretation of one of the most impressive and elevating passages in the QUr'an. The manner in which A vicenna treats the doctrine of the Resurrection is still better illustrated by the interpretations that he places on some of the verses of the Qur'an. it would soon be realized that death is an act of divine wisdom. 3 Cf. so on its return the soul leaves the body behind and goes to join the intelligences and through them the source of all emanations. then as souls and then as bodies. Hence to speak of the resurrection of the body is only figurative. and a world of the mind. J8~ 183 . which for him was something that is in essence divine. It is the soul and not the body that is immortal.r He does not claim to be a fundamentalist. who is God. Only a Muslim can appreciate its boldness. 4 a Sura 24.s but he dwells at some length on the I i ({~9-'. meant to make the ideas more vivid. He seeks philosophical meanings. but will gradually disappear until it has gained the happiness that is its due. and he incorporates them into his system.Tt is. I It is ignorance of what there is in store that makes us so fearful of death. and that not many after him had the. and shows clearly the attitude he chose to take. Tls'a Rasa'il. And just as there is a life of the will and a natural life. significant that the authors of the Epistles were among the very few-if there were anywho had taken that attitude before him. a Sn~fa. And in this he is very much influenced by Plotinian ideas passed on to the Islamic world through the so-called Theology of Aristotle. a world of the imagination._J' . with sincerity and in perfect good faith that he accepts the Scriptures of his religion. Pulfrom s its material attachments. Tis'a Rasa'il. then that of the senses deserves to be considered 'the world of the graves' . Mehren.' is a most revealing example of his religious writings. verse 35. others which we can prove by reasoning and demonstration. And if the consequences of such a possibility be considered.AVICENNA PROBLEMS OF RELIGION death is nothing but the separation of the immaterial . Tis'« Rasii'il. and by striving towards it with constant effort and action.a Avicenna was not a moralist and all he has to say on ethics is derived from Aristotle. Otherwise. Risiilat al-'AU. If men were immortal. He goes still farther and asserts that if there is a world of the senses. not in the pleasures of a fleeting life on earth. the world would have no room to hold them. It is in these that it finds eternal existence.. we believe. to accept the Scriptures literally and in their entirety is an affront to the intelligence. The perfection of the rational soul is achieved in attaining full intellectual knowledge. What it has suffered or will suffer as a result of what the body has done or sustained will not torment it for ever. lliiAiyyiit. And just as beings originated first as intelligences.2 where God is spoken of as 'the light of the heavens and earth. courage to do the same. and the world of the mind is the true 'abode and that is paradise. and does not hesitate to quote Greek philosophers in support of his interpretations. Pi 'llm al-AIcAliiq. If death is a release that men should never mourn. Najiit. what about the doctrine of the Resurrection insisted upon by religious dogma? Here Avicenna is obviously unhappy and feels constrained to point out that there are things which the religious law lays down. however._' Cf. Ft Daf' al-Ghamm min al-Maut.
is called an angel. the consequences would constitute a still greater evil. and still others have bodies.'3 And the third are the angels represented by the heavenly bodies. the evil has come from outside. The spiritual angels that are intelligences and stand highest. it may be something that causes pain or sorrow as the result of some act. an evil. 4 Cf.!. 'It is said that the celestial spheres are living. immortal.'5 The angels that act as I Najat. come down to those that are only one grade above corruptible bodies composed of matter and form.86. immortal. For the vindictive man vindictiveness is a perfection. Najat. Then come the spiritual angels that are called souls. 5 Ft Ithhat al-Nubuw. then the celestial spheres are called angels. God may be said to desire the good as the essence of everything and evil as an accident.result fails to reach fruition. These last differ in grades. Our judgement of evil is always relative and in terms of human action it is with reference to something. reasonable. The highest in rank are the spiritual angels that are pure and free of matter. As an accident it is the concomitant of matter and may come from outside and be an external factor. And If the plant has failed to respond to warmth and growth. or an evil with relation to something that is at least possible [of attainment]. It is not every ~orm of negation. • Risiilat al-l. Hence it is not something definite and determined in itself. Some have intelligences. do not die. intellectual. should this quality in any way diminish in him.at." In the first case of course it is a greater evil. al-ma/ii'i/ca al-muqarraDiin.IuJiit/. p. If clouds gather and prevent the sun from shining on a plant w~ich as a . but the non-existence of what has been provided by nature for the perfection of things. 18S 184 . In essence it is the absence of somethinga negative and not a positive element.'> With this definition Avicenna goes on to explain that angels are intermediaries between the Creator and terrestrial bodies.4 Of the third class.AVICENNA problem of evil. and 'these are the active angels. the answer is that such a situation would not be suitable for our genre of being. If we were to suppose the absence of those privations which we have called evil. as a result of some defect in it. otherwise there would be what might be called universal evil. it may be just the lack of what brings happiness and provides for the good. are called by the philosophers active intelligences. 474. I I PROBLEMS OF RELIGION he would consider it an evil that has befallen him. To the question why God did not make the pure good always prevail unaffected by the presence of evil. p. It could possibly be conceived of absolute being emanating from God and occupied with matters pertaining to the intelligence and the soul but not of the world as it is. What are angels and where do they reside? 'An angel is a pure substance endowed with life and reason. and correspond to those that in the language of religion are spoken of as the angels nearest and closest to God. others have souls. reasonable. 'All the causes of evil are to be found in this sub-lunary world ••• the evil that is in the sense of privation is an evil either with relation to some necessary or useful matter . 3 Najat. It 'may be a defect coming from ignorance or from the disfigurement of the body. p. or from inside and be an internal factor. and for those who may lose something as a result of it. In this sense of the word there is much evil in the world. U9. Its interaction with the good is not wholly devoid of usefulness and may be sometimes even profitable. Burning is for fire a perfection.•. they are called intelligences. It is not a necessary feature of the universe but a by-product that seems to occur unfailingly. When we measure the two we still find reason to be grateful that there is more good in the world than evil. Here again we find Avicenna following Aristotle who believed that there is no evil principle in the world and that there is no evil apart from particular things. the evil has come from the plant itself and. but it cannot be said that it is overwhelmingly more than the good. and beginning with the most noble of them. :l. Avicenna remarks. Evil takes various forms.» since it necessarily occurs. and it is of course at the same time an evil for those who suffer from his vindictiveness. and the living.
They speak in the sense that they make themselves heard. though somewhat related. There may be little in his early works to show an inclination towards mysticism. the most sensuous forms of which were promised for the righteous and for the wicked in the world to come. Aristotle had discussed pleasure and pain at great length. He arrives at the conclusion that the highest and purest form is the intellectual pleasure available to those who can rise above the vulgar notions and practices of the rest. The prophet sees and hears them. And when his works were rendered into Arabic. Under Plotinian influence he emphasizes the two elements of pleasure. I though the majority followed along Aristotelian lines. and what may be called good-fortune? The common people suppose that the most intense of pleasures are the sensuous. These can be attained far more effectively and fruitfully in the intellectual sphere. but not in the language of men and animals. and the mind has another. That being the case. * * * * Scholars have been undecided as to whether to call A vicenna a rational mystic or a mystic rationalist. and sometimes openly challenged its validity. The man who wishes to become a leader deems it necessary to forgo many forms of pleasure. producing some very curious theories. his hectic life could not have been particularly conducive to such a discipline. and they do not always agree. the subject became a favourite topic of discussion among the Faliisifo. and the comparative value of each. they often gain a pleasure beyond anything we can imagine. Zad eI-Musaforin. none of which he could accept in their entirety. The Greeks. And the same may be said of those who choose to renounce the world and become ascetics. and Aristotle in particular. 191. What is happiness. Book X. 186 187 . and with more elevating results. which is not altogether what Aristotle had said. They produce a satisfaction deeper and more lasting. perfection and the perception of it as such. His detractors hit back by saying that this was because he knew exactly where he was destined to end and he feared the punishments in store for him. • Ihid.of pleasures. but not with his ordinary senses.a and had analysed the views of his predecessors.AVICENNA PROBLEMS OF RELIGION intermediaries between God and His prophets. What he tried to point out without expressly affirming it. and finding far more satisfaction in the accomplishment of his aim. In Persian one of the most interesting and detailed arguments is found in a work of Na~ir Khosrowr who strongly disagrees with Razi's definition of pleasure as nothing but a return to the normal state. that act as the souls of the celestial spheres. Ethic. For A vicenna what is more important is the relation of the different forms of pleasure to one another. We see the man bent on avenging a wrong done to him. had stressed them long before him. in order to attain the greater pleasure of realizing his ambition. The human emotions have one conception of good and evil.'! And in like manner 'pain is a perception • • • which to the perceiver is a harm and an evil. p. and the stories about his association with celebrated mystics are not authentic. They are the bearers of inspiration. viz. but that is not difficult to disprove. they differ according to the criteria with which they are judged. He seemed to have had a natural aversion to this doctrine. was the contrast of this conception with the doctrinal ideas of pleasure and pain. what should be said of intellectual pleasures that are more elevated than both the sensuous and the inward? But what exactly is pleasure? 'Pleasure is a perception and an attainment in the quest for that which to the perceiver is a perfection and a good in itself. without the least regret. are those that possess souls. There is of course nothing new in his appreciation of the pleasures of contemplation.'l But good and evil are relative. These and many other similar examples go to show that the 'inward pleasures' are far more powerful than the sensuous. And yet he devotes the closing pages I /sharat. deny himself of all such forms. 3 Nlcom.
There are besides a number of short treatises. they may take the path to 'the world of sanctity.' There are certain things that are hidden within them. He is the man who bears the name of'iirif. Mysticism is a native growth in many parts of the world. is called an ascetic (tahid). he likes to point out. separated and free. and perhaps for that reason his is an intellectualized form of mysticism that never became a fundamental part of his philosophical system. in some cases. revelation. active and ambitious man. Interest. Gnostic and perhaps Hermetic provenance. 189 . The things that they demonstrate to everyone are denounced by those who disapprove of them.'I These introductory remarks summarize in some ways Avicenna's whole attitude to Sufism. Some ideas and practices can be traced to India.AVICENNA PROBLEMS OF RELIGION of one of his latest books. while others are indubitably of Neo-Platonic. He who has been initiated into the mystic order. he who devotes his whole time to religious practices such as prayers. The intellectualizedform ofNeo-Platonic mysticism seemedcongenial and more to his liking. except that they were of entirely different temperaments themselves. the Iskariit. is considered a pietist and a worshipper C iihid). and. and there is no doubt that what is known as Sufismwas in its essentialsa distinctive contribution of the Persian mind. The theory that the chief features of the Islamic form of this discipline are all of Neo-Platonic origin has been discarded. Farabi had done the same before him. or during the period of its sojourn in the human body. and that his interest in the mystics and their way of life did not develop early in him. The sources of Avicennian mysticism are twofold. to what is avowedly mystic thought. viz. not all of which have been published. It is not therefore surprising that he should have gradually come to see the significanceof the mystic path. and there is much that is similar in their attitudes towards it. Avicenna was a highspirited. /shiiTiit. Often in his psychology he speaks of certain relations of the soul as being mysterious and baffling to the human mind. and the interpretations which it offered for problems that he had found difficult to explain. Unlike his predecessor. Avicenna tells us. even the violent condemnation of Persian Sufis. fasting and nocturnal vigils. Yet he had never denied what may be called divine truths and spiritual values. and 188 he incurred the displeasure. There is the indigenous element and the Neo-Platonic. As a philosopher he was drawn inescapably to some of its principal conceptions. and others that they show publicly. 198. appreciation and acknowledgement they contain. though the indigenous element is rarely absent. but it is safe to assume that they are all rather late works. though oddly enough the writings of the Faliisifo may have had something to do with it. and he who concentrates his thoughts on the Almighty I Cf. The importance that some have attempted to give to this aspect of his thought is hardly justified. has states and stages particular to him and the life that he leads. but no commitment. and highly praised by those who know and understand. containing mystic tales and allegories. Exactly how they found their way into Sufism is not clear. He who renounces the goods of the world and all the benefits that they offer. hoping to find some help. and the power of prayers. though there may be some relation between the two names). the knower (and whom here we might call the gnostic without in any way associating him with Gnostics. Nevertheless foreign influences from both the East and the West coloured many of its doctrines. but in a very objective tone. This explains why there is so much of Plotinian thought in his account of the soul. p. not pretending to be one of them. Sufis are different from asceticsand pietists. He had admitted and justified such things as inspiration. and 'we shall relate them to YOU. whether in relation to God. have a way of escaping from them in order that. The dates of these have not yet been determined. Avicenna does not seem particularly attracted to the devotional aspects of Sufism. He writes with appreciation and sympathy about the mystics. Mystics while still inhabiting their earthly bodies. It is in such cases that he turns to mysticism.
There is nothing that he would prefer to knowing God and worshipping Him. and that necessitatesa lawgiver who must prove by signs and symbols that he has been appointed by God. 199.AVICENNA PROBLEMS OF RELIGION so that the light of God may dawn upon his inner self. a rising above everything other than the Truth. but can it be said that he must have had some mystic experience himself? Certain scholars have been positive about it. and there are cases where they are found in combination. With it he gains the ardent desire to bind himselfwith the bonds of faith. In contrast to the practical requirements of the ordinary man. These have to come from God.1 . renunciation is abstention from anything that may distract his inner self from its intimacy with the Truth. there is agreement and disagreement between him and the others. a constant exchange of things and ideas. It means that he has not yet attained full satisfaction and joy. It is then that the intimate of the inner self becomes enamoured of the brilliant dawn. It is that with which he strengthens his resolve to demonstrate his convictions. lovingkindness and bounty at work. He has also to promise reward and punishment. p. In the regulation of this all-encompassing order we can see God's wisdom. He thereby turns them away from the near regions of pride to the distant realms of divine truth. The first stage in the progressive development of the mystic is what they call 'the will' (al-irrida). Man does not live alone. and the position of worshipper is a noble relationship towards Him. the gnostic seeks the truth only for its own sake. however. is given the special name of knower (' ririf) or gnostic. They are taught how to do so. but an intermediary leading to Him who is the ultimate goal sought by all. But for the gnostic it is a discipline for his energy and an exercise for the estimative and imaginative faculties of his soul. though we do not find sufficient evidence for that. and that love and devotion become an established habit. so that whenever it wishes to penetrate into the light of truth without doubts or fears to obstruct. 191 190 . It is as though it buys the goods of the next world with those of this world. in the form of rewards that he has been promised. when Truth turns its effulgence upon them with nothing to mar the light. not because of hope or fear. It is then that the truth is no more the goal. prove an intimate knowledge of all that the mystics strive for and ultimately claim to have attained. It is as though the pietist labours in this world for a payment that he will receive in the next world. have the advantage of deriving from these forms of worship a profit peculiar to themselves when they tum their facescompletely towards God. Whereas with the gnostic. the other is the respect that he entertains for the gnostic and his graphic description of mystic experience. two points are noticeable. they are enjoined to say their prayers so often because repetition helps them to remember God in their daily lives. One is the scorn with which Avicenna speaks of ascetics and pietists. The passage I ]shiiriit. There must be a law to regulate these relations. but due to the fact that God deserves to be worshipped. And yet among others besides the gnostics ascetism takes the form of a business transaction. he is in social contact with his fellow-men. and that makes people try to know Him and worship Him. it is not surprising that he had no use for ascetismor pietism. he cannot do everything for himself. He stands to the real gnostic as a young boy in comparison to the man of mature experience. There they will abide in peace with the intimate (sirr) of the inner self. In this passage in which we have tried to be as faithful to the original as possible. The gnostics. which in tum assists in the maintenance of justice necessary for the survival of the human species. does. In a similar manner pietism or worship is with other than the gnostic a commercial transaction. These qualities are sometimes held separately. it will be encouraged by that light until it finds itself wholly and completely in the path of sanctity (qudS). on the other hand. When the ways of his life are remembered. And yet he who gives an intermediary position to truth is to be pitied in a way. nor can he think everything by himself. for obvious reasons.
he would be left sad and perplexed. and the other following the mystic experience. The third form requires subtle thought. This acquaintance or mutual knowledge is at first only sometimes arrived at. implies an exchange and a give-and-take in addition to it. These are the occasions they themselves call 'moments' (awqat). he is overwhelmed by the frequency with which the moments come to him. all that there is hidden in the gnostic is revealed to him. and the lightning glimpses would be transformed into flames of light. he is carried away to the realms of sanctity by the evocation of a happy memory. He has used his will and strengthened his resolve. later I Cf. Until the time comes when.irfan). At that limit. and therefore I the ecstasies. the sermon of a preacher when it is intelligent. he claims that the gnostic gains what he calls a willing acquaintance (mu'arifo) at that stage. leads to real ascetism. and become concentrated solely on what is sanctified. He gains an acquaintance that will remain permanently with him and whose constant companionship affords him profit and satisfaction. he has reached the highest degree and attained the goal. and travelling far away even when in his place.02. so that he seems to be absent even when present. p. Should that acquaintance ever desert him thenceforth. G 193 . And when describing how he reaches the state of complete knowledge (ma'rifo). p. with no more exercises necessary. the use of melodies to serve the faculties of the soul. 203. his labours have borne fruit. In such a case the imaginative and estimative faculties cease to be occupied with matters that are base and low. he is a 'seeker' (mudd). with discipline and exercise he has passed the different stages of self-purification. [sharat. And if he perseveres in the exercises. [sharat. But he needs other things in addition. eloquently expressed and delivered in an impressive tone. It might be said that he sees the Creative Truth in everything. such as the practice of worship associated with thought.a). And these moments are preceded and also followed by periods of ecstasy (wajd)-one period leading to the moment. and every time that he does so. And third. and make a satisfied and confident soul rule :mpreme.' So far the man of the mystic path has gone through states and stages of preparation. and a certain limit has been reached. Making use of the same Arabic root meaning to know. Second. It is then that by merely fixing his eyes on something. Avicenna introduces what seems a new idea. The first form of discipline. So long as he is in that stage. It is then that the intimate of his inner self moves towards the realms of sanctity that it may profit from the bliss of attaining that goal. to enable him to overcome the self that rules the passions. though based on knowledge. The second form includes various exercises. the moments will become more frequent. He is now in contact (ittital) with God. he says. He must have spiritual discipline and exercise (riyaq. And yet he can proceed still farther. First to enable him to tum away and disregard all things save the Truth. furtive glimpses of the light of God begin to be revealed to him-visions 'delicious to behold. The long periods of quietude (sakma) have ended. The purpose of these is threefold. but if he penetrates into this relationship of acquaintance. it is to render the 'intimate' more gentle and capable of yielding his undivided attention and complete devotion. His word connotes some sort of reciprocal relationship which. :1. to which may be added the words that are chanted. and his companions can notice that he is no more at rest. and thus bring peace to his soul. He has been describing throughout the journey of the gnostic ('arif) along the mystic path in his quest for knowledge or gnosis (. A vicenna unexpectedly changes his terminology. not by the force of passion.! In the account on which this last passage is based. And when that has advanced sufficiently.AVICENNA PROBLEMS OF RELIGION to attach himself to that unfailing source of determination.' Like lightning they appear and they are gone. Exercise can carry him to the stage where his 'moments' would be thought to be periods of 'quietude'. it becomes less and less apparent to him. his ecstatic escapes would become habitual. and pure and chaste love directed by the beauty of the beloved.
He could not be otherwise now 194 195 . and total abandonment to Him who is creative and true seems the only salvation. The traveller having climbed to the surnmit and reached his destination. now at the realms of Truth. A vicenna had spoken of this twofold relation of the human soul-its contact with the heavenly world. one must be of those who have reached the fountain-head. but those are very difficult to understand. the description of them by Avicenna had a profound influence on his successors. take the view that he was animated solely by the desire to analyse an experience that he is prepared to accept as profoundly true. 180. There is first the state in which he begins to have 'moments' . or more. finds himself completely transformed. he sees another also. the renunciation is in order to gain freedom. His values are changed and his outlook surprisingly altered. and after that he is hesitant and never sure. In some of his other works also. which is the state of complete unity. • Cf. words fail to describe them. is a common theme in Sufi literature. We. And if he ever turns again to his soul. not of those who have only listened to the tale. It begins with separation. and fixes his eyes solely on the Lord of sanctity. and then a complete refusal. Gauthier. but of which he does not claim personal knowledge. and its attachment to the body that it occupies. 204. edit. and finally he 'arrives' at union with the Creative Truth. one has t~ be a man of contemplation and not of lipservice. and we find it difficult to agree with the claim that it was an Avicennian contribution. It is then and there that he reaches the ultimate goal. modest and humble withal. maintain that he is writing of things he passed through himself. Once he has passed all the stages of exercise and has truly attained the goal. They claim in addition that while certain notions are related to Plotinan thought. it is only to see it looking on. others are undoubtedly Avicennian. There are specific elements in this quest for gnosis which we call mysticism. Gardet. until such time as he arrives at oneness. Whether the stages are divided into only three. and he will be overjoyed to find that his soul has traces of God upon it. This is why the gnostic is so happy and gay. 'There is in truth the arrival (al-wUjul). and we find it quoted by Ibn Tufail in Andalusia> Here again the problem is posed: Does this exposition prove that Avicenna had a genuine mystic experience? Some have insisted that this is the casejs and I 3 /s/ziiriit. Cf. /fayy hen Yaqd/ziin ••• . To arrive at the proper conception. p. The separation is from things that might tum him away from his quest. they can better be imagined. and not to appreciate its splendour. finally relinquishes his self completely. And he can proceed still farther and reach a stage where it depends no more on his desire. and the idea constantly occurs to him to leave this world of illusion and seek the realms of Truth. The gnostic who stood with reluctant feet gazing. Through the execution of these acts the gnostic succeeds in concentrating on the essential attributes of God. and dependence on those faculties that he always found so submissive in himself now seems an exasperating weakness. There are certain degrees to which a . Whenever he notices one thing. however. then there is a denunciation. This dual activity. and the complete refusal is the neglect of all else save the goal. the denunciation is of the things that used to engage and occupy him.gnostic can pass even beyond these.'1 This account of the life-long journey stresses the different stages through which the gnostic has to pass. in order that he may profit by them and eventually acquire them. p. then a renunciation. then at his own soul. however. the intimate of his self becomes a highly polished mirror turned towards the Creative Truth.AVICENNA PROBLEMS OF RELIGION he can have it when he wishes. Occupation with things that he had most reluctantly renounced now becomes a tiresome and frustrating labour. then come the periods of 'quietude'. He takes one look at the realms of Truth and another at his soul. and even then it is not the true thing. and then there is a standstill (wuquf). after that he achieves 'contact'. Pensee religieuse d'Avicenne. Pride in the qualities that adorned his self appears misguided even though justified. And pleasures from on high will come pouring down upon him. of personal insight and not of hearsay.
But once he has reached and gained the station of 'arrival' (wu~iil). It is the strength that comes from joy. Fear and sorrow weaken a man. an admonition for the accomplished. according to the plans and purposes that they have in view. In those moments when he has turned towards the Truth. let him blame himself. H. 2. or the intimate of his soul cause a simple motion to disturb him. IsAarat. pp. and the explanation not difficult to see. and when the concerted exercise of one faculty prevents the operation of digestion and therefore of hunger. The same applies when they interact with the physical forces and requirements of the human body. These psychic powers can weaken or strengthen the physical forces. there is nothing contrary to the natural law. he is grieved and annoyed. A vicenna has left some tales couched in symbolic language and of semi-mystic. The gnostic has states in which he cannot bear even the murmur of the breeze. And everything has been provided for him who was created for it. Perhaps it does not suit him. when they disdain all earthly things. Some continue the religious practices. and finds man an object of pity in search of what is utterly futile.' Avicenna ends this chapter of the Ishiiriit with the remark that 'what is comprised in this section [of our book] is a source of laughter for the thoughtless. Others do not hesitate to partake of what life can offer. or doing something no one else is capable of.> In their desire to bring about a closer rapprochement with religious belief. It was seen in the study of psychology that the faculties of the soul are in constant interaction with one another. it was seen that particulars are engraved in the world of the intellect in a general way and universally.07. and also' to the other. p. Avicenne et le Ricit visionnaire. A vicenna says. He never loses his temper with anyone. and confidence and faith in God that make a gnostic capable of doing things others cannot. • Cf.07-10. 2. and sever his relations with all else. He who has heard it and felt revulsion. and forgetful of all that was done to him because he is now occupied wholly with God. semiphilosophical slgnificance. Some choose to be austere and lead a humble life-sometimes even a miserable one. 2. while hate. do not be surprised and do not disbelieve it. vols. He is brave because he does not fear death. A typical case is when fear paralyses sexual passion. And the reason why he can foretell the future sometimes is that he gains an unusual capacity to judge from the past and reason things out and thus arrive at a conclusion. 196 197 . Furthermore. and that they can for long or short periods render one another ineffective and inoperative. Hence in this case also the process is a natural one. he would rather advise and give gentle counsel. much less such unnecessary preoccupations as might engage him. and those who develop the proper disposition can have these particulars engraved upon their own souls to a certain extent. magnanimous because his soul is now too great to worry about the evils committed by his fellow-men.! Besides this analysis of the mystic life. rivalry and also joy make him stronger. devoting attention to this world. generous because he loves no more what he now deems futile. or to try to combine the two.he then has the choice either to devote himself wholly to the Truth. All these have a perfectly natural explanation. And how could he be when overwhelmed by such a sense of pity for man? Instead of administering blame. IsMrat. or even foretelling a future event. The gnostics differ sometimes in their modes of life. Corbin. and prevents the execution of the most ordinary acts. the Islamic thinkers had claimed that there was an exact correspondence between the different intelligences of which the philosophers spoke and the I Cf.AVICENNA PROBLEMS OF RELIGION that he sees the truth in everything. should his self raise a veil to separate him. nor is he ever very angry. others neglect them after their 'arrival. or digestion.'I What of the prodigies usually associated with these mystic divines in the popular imagination? If you hear of a gnostic going I for long periods without food. In fact psychic powers directed by the faculties of the soul have complete control over the body.
to remain constantly in flight and not hide within the nest lest that may become a trap for them. And as to the Active Intelligence. it was identified with the angel Gabriel. the Dator F ormarum. In a dramatized tale. which symbolize the search after knowledge. They cannot be discarded now. According to the interpretation of his pupil who has left a commentary on this tale. It is the abode of Matter. his companions are his senses. That is where the light sets. It is by logical thought and reasoning that he must be guided. Another such allegorical tale is entitled the Treatise of the Bird» Here a bird wings its way from place to place in search of a friend to whom it can confide its secret. and hide what has been apparent. though it is not given to everyone to travel the whole way. and can then embark unimpeded on his quest. wherein is to be found everyI thing that is composed of matter and form combined. They flew over happy fields and lovely I lfaiy ilm Yaq\. Then there are the realms of the East. In reply to the request that he should accompany him on his journeys. The East is where the sun dawns. It is where the sun rises in all its glory. the old man remarks that that could not be done while still hampered by the presence of the companions. The bird calls out to its 'brothers in truth' to share one another's secrets. But how is he to find his way. These souls were celestial beings possessing imagination. only to find that such beings are rare now that friendship has become a matter of commerce. and the venerable man (from whom he is to seek information). Risiilat al-Tair. The time will come when he (the narrator) will be entirely free and separate from them. and they are in constant strife. That should be sufficient to prevent him from getting lost in the wilderness. there it resides for all who seek it. There are three directions he could take. To it must such faces turn as seek illumination. And thirdly are the lands situated between the East and the West.we find A vicenna relating how one day he went out for a ramble in the vicinity of a town together with a few companions." and my lineage "son of the vigilant. The people in the West are strangers from distant climes. Mehren. In their account of the cosmos they had argued that each of the celestial spheres had a soul of its own. to love death in order that they may live. The bird then begins to relate the story of how once together with other birds it was beguiled into a pleasant place. and there they were all caught in the nets that had been carefully laid for them." . they are places of darkness and therefore of ignorance. how can he choose between the different paths? Here the rationalist emerges. and to join in an effort to seek perfection. and there chanced to meet a man who though to all appearance extremely old. none other than the Active Intelligence personified. and might rightly be called celestial angels.•. 'My name is "the living.AVICENNA PROBLEMS OF RELIGION angels about whom religion was so positive. These reflections were expressed in symbolic language a thousand years ago by a philosopher who at the time of writing was actually a prisoner deep in the dungeon of a fortress. The polar regions should be avoided. Until one day the narrator-bird managed to escape from its cage. he himself represents the seeker after truth. edit. and join them in their flight to lands where they could all be safe. as some others had done before it. My profession is unceasing travel in the regions of the world . 'and as to my home-town. There are first the regions of the West and the countries beyond it.<in. and my face is always turned toward my father who is "The Living. had the full vigour and alertness of youth. It bids them make manifest their inner selves. and that not until a brotherhood is established based on truth and guided from above. That should lead him to knowledge which is an all-revealing source of light. It is he who can confront his tomorrow with confidence that is truly alive and awake. and with whom it can share its sorrows. can there be free communion among all. to remove the veil that separates their hearts." . It is the home and fountain-head of Form. it is the city of celestial Jerusalem (the sacred abode). 198 199 . the old man says. and the sun is the giver of forms. Above them stood the intelligences who might be considered the same as the Cherubim. and they suffered in their captivity.
Just as his Shija. A Treatise on the Canon ••• 200 201 . but the Canon though already printed in full.s and still awaits a patient and competent student. Greek medicine reached the Islamic world before philosophy. The Shija.! but of the second we only know through the short commentary of Tfi~i. But they continued till after passing over nine mountains. we are told. is an encyclopaedia of the medical knowledge of his day. One was of Hermetic origin and had been translated into Arabic by Hunain.AVICENNA mountains where they were tempted to remain. In Baghdad. has been frequently if not comprehensively studied. Of the tale of Salanum and Absal there were two versions. They entered into the palace and were invited into his presence. a Christian monk who lived in Alexandria not long before the Arab conquest.I has been examined only in parts. together with the results of his medical practice and the experiencethat he had gained. The first version has survived. yet he is commonly referred to as 'the prince and chief of physicians'. Carame. into Arabic. • Cf. Romae. Persian and Indian medicine became incorporated with the Greek. they finally reached the City of the King. Avicenna may not be as great a physician as a philosopher. was by Avicenna himself. Gruner. which was to become equally renowned in both the East and the West. edit. r CHAPTER VII MEDICINE AND THE NATURAL SCIENCES Cf Tis'a Rasa'il. Already in Ummayad times a Persian Jew by the name of Masarjawaih had translated the Pandects of Ahron.. this voluminous undertaking. he worked at the same time. and it is supposed that with him Islamic medicine reached its zenith. The former was basically Aristotelian with important contributions of Avicenna's own. was concerned with all aspects of philosophy. When their eyes fell on the King they were so overwhelmed that they forgot all their afflictions. It also includes what his immediate predecessors had written on the subject. whereupon the King assured them that such things would never happen again. In concept as well as in method there are points of similarity between the two books on which. whilst his minor treatises deal with separate diseasesand their treatment. this comprises in the main what Hippocrates and Galen had taught. MDXCIII. to which he refers in the /sharat. He gave them courage and they reported all that they had undergone. The process had in fact THE r Canonis MeJicinae. though the whole of it has not yet been edited. the other. Canon of Medicine is Avicenna's chief medical work. for he was sending his Messenger whose mission was to make sure that peace and justice should prevail. | https://www.scribd.com/doc/51068801/afnan | CC-MAIN-2018-17 | refinedweb | 71,646 | 68.47 |
In Python, how can I print the current call stack from within a method (for debugging purposes).
Here's an example of getting the stack via the traceback module, and printing it:
import traceback def f(): g() def g(): for line in traceback.format_stack(): print(line.strip()) f() # Prints: # File "so-stack.py", line 10, in <module> # f() # File "so-stack.py", line 4, in f # g() # File "so-stack.py", line 7, in g # for line in traceback.format_stack():
If you really only want to print the stack to stderr, you can use:
traceback.print_stack()
Or to print to stdout (useful if want to keep redirected output together), use:
traceback.print_stack(file=sys.stdout)
But getting it via
traceback.format_stack() lets you do whatever you like with it. | https://codedump.io/share/ko7s9aUffdfq/1/print-current-call-stack-from-a-method-in-python-code | CC-MAIN-2018-05 | refinedweb | 129 | 68.57 |
#include <hallo.h> * Will Newton [Thu, Jul 14 2005, 05:36:05PM]: > > Thus, it won't contradict with your requirement to > > be able to just build-depend on libXXX-dev. > > I may be wrong, but I thought it was incorrect to build-dep only on a pure > virtual package? e.g.: > > Build-Depend: xlibmesa-gl-dev | libgl-dev I just though the same. In addition, that proposal removes the possibility to depend on a certain -dev package and all newer versions (by setting a versioned dependency on libfoo-dev). Regards, Eduard. -- <vicbro> ich kotz gleich. warum reichen 512mb nicht für konqueror, konsole, kopete, kontact, ksirc, openoffice und 10 weitere programme aus? <jjFux> kbloat, kmemeater, kleak ...
Attachment:
signature.asc
Description: Digital signature | https://lists.debian.org/debian-devel/2005/07/msg00678.html | CC-MAIN-2017-13 | refinedweb | 121 | 57.87 |
Issues
ZF2-18: Extending Zend_Log using namespaces
Description
In Zend_Log::factory in line 139 (ZF 1.11) an instance of Zend_Log is created with $log = new self;.
Let me give a use-case to explain:
somewhere at bootstrapping:
$autoloader = Zend_Loader_Autloader::getInstance(); $autoloader->registerNamespace("My_"); $autoloader->setFallbackAutoloader(true);
extending Zend_Log:
My_Log extends Zend_Log { public function log($message, $priority, $extras = null) { // do something else parent::log($message, $priority, $extras); } }
Also at bootstrapping:
$logger = My_Log::factory(...);
So the My_Log::log method never will be called -> $log = new self;
First option is to override the Zend_Log::factory and replace $log = new self to $log = new My_Log, but this is urgh. Better code this:
$log = new static;
With this pice of code it is possible to get, due to late static binding, a instance of My_Log, and not Zend_Log...
What do u think?
Tested with ZF 1.8 - 1.11 - works fine (of course > PHP5.3)
cheers
Posted by Benoît Durand (intiilapa) on 2011-06-06T21:06:04.000+0000
@Eric ZF1 must be compatible with PHP 5.2.
Posted by Matthew Weier O'Phinney (matthew) on 2011-06-06T21:15:21.000+0000
I'm going to move this issue to the ZF2 issue tracker, as LSB is only available in PHP >= 5.3, and ZF1's minimum version is 5.2.6. There may be other ways to potentially support this in 5.2, but the proper way is using LSB.
Posted by Benoît Durand (intiilapa) on 2011-06-07T04:55:52.000+0000
All factory methods of logger, writers, filtesr, and formatters are being refactored within ZF2.
Posted by Eric Andre (eandre) on 2011-06-07T08:55:23.000+0000
Okay, i dont respect the compatibility. So thanks for regarding this issue.
Posted by Benoît Durand (intiilapa) on 2011-09-03T08:26:39.000+0000
Once the common API (puggable, configurator, etc.) will have been decided for the core components of ZF2, Logger will adopt it. Being able to extend any core component is a requirement for this solution.
It is also possible to consider including events in order to customize the logging.
Posted by Evan Coury (evan.pro) on 2011-12-21T22:14:42.000+0000
I see no reason for us to wait until after we refactor for the new configuration style to make this change. LSB is the correct way to handle a situation like this, and it's a simple enough change. I went ahead and issued a PR for this:
Posted by Rob Allen (rob) on 2011-12-22T19:38:20.000+0000
Merged to master | http://framework.zend.com/issues/browse/ZF2-18 | CC-MAIN-2015-18 | refinedweb | 429 | 68.16 |
Using Progressbar.js as a Vue Component
vue-progress
Projects can require a lot for elements and in Vue projects, there are many plugins to use directly to fulfill a specific need. Vue components which serve a certain purpose are fairly easy to use and one of them is the vue-progress which serve to use Progressbar.js as a Vue Component. Look how progress bars can look in the demo page.
Take a look at the example below to see how to install and use.
Example
Install
yarn add vue-progress
Import as a vue plugin
import VueProgress from 'vue-progress' Vue.use(VueProgress)
Use it directly to your template binding to props:
<progress-bar </progress-bar>
or
<progress-bar</progress-bar> ... options: { color: '#E91E63', strokeWidth: 0.9, }
Result:
To see more ProgressBar component attributes and vm methods head to the GitHub repo where you can also find out how to build custom progress bars. | https://vuejsfeed.com/blog/using-progressbar-js-as-a-vue-component | CC-MAIN-2020-34 | refinedweb | 156 | 63.9 |
Hi this code is working fine storing on a shared memory integers, but i want to store strings, how can i modify it to do that?
For example the output will be Written: This is the line number 1 and in the next line Written: This is the line number 2
#include <string.h>
#include <stdio.h>
#include <memory.h>
#include <sys/shm.h>
#include <unistd.h>
void main()
{
key_t Clave;
int Id_Memoria;
int *Memoria = NULL;
int i,j;
Clave = ftok ("/bin/ls", 33);
if (Clave == -1)
{
printf("No consigo clave para memoria compartida");
exit(0);
}
Id_Memoria = shmget (Clave, 1024, 0777 | IPC_CREAT);
if (Id_Memoria == -1)
{
printf("No consigo Id para memoria compartida");
exit (0);
}
Memoria = (int *)shmat (Id_Memoria, (char *)0, 0);
if (Memoria == NULL)
{
printf("No consigo memoria compartida");
exit (0);
}
for (j=0; j<100; j++)
{
Memoria[j] = j;
printf( "Written: %d \n" ,Memoria[j]);
}
shmdt ((char *)Memoria);
shmctl (Id_Memoria, IPC_RMID, (struct shmid_ds *)NULL);
}
You need to copy string character by character to shared memory. Actual pointer pointing to the variable in shared memory needs to stay outside because shared memory can be in different addresses in different process. (You could use delta pointers but they are a lot easier in C++ boost::offset_ptr)
For manipulating strings there is string utility functions in string.h. Specially strncpy would be useful when moving strings to different memory locations.
Also it would be good idea to use new posix shared memory instead of your current sysv implementation. You can see more details about posix shared memory in shm_overview man page. Of course if you have an old OS that supports only sysv interface then you have to stick with old api. | https://codedump.io/share/oFo3K4tU4lJE/1/store-an-string-on-a-shared-memory-c | CC-MAIN-2017-51 | refinedweb | 280 | 59.43 |
Happy New Year! Looking back at 2017, it was a great year for ArcGIS Pro extensibility. We saw many developers taking advantage of the Pro SDK in extending Pro to meet their organizations’ specific needs and workflows. The ArcGIS Pro teams developed powerful new Pro SDK functionality, and grew the SDK significantly. Here’s a brief overview of some highlights from the 2017 Pro releases:
Pro SDK 1.4:
- Solution Configurations – a new add-in pattern / template which allows you to customize the Pro UI/UX at start-up.
- API enhancements – New classes and methods for working with Geodatabase, Geometry and new UI controls.
- Light/dark theme styling – with the new Pro 1.4 light and dark theme capability, the SDK was expanded to allow add-ins and configurations to be styled for optimal visibility.
Pro SDK 2.0:
- API enhancements – New classes and methods for working with Content, Editing, Geodatabase, Geometry, Mapping and Raster.
- Visual Studio 2017 Support – the ability to build your add-ins and configurations in the latest version of Visual Studio.
- Additional styling capabilities – New styling at 2.0 with updates for brushes and colors.
A custom start page from the sample solution configuration, ConfigWithStartWizard:
Solution Configurations offer developers a powerful new way to bring a new Pro user experience to their organizations. Also, developers were able to take advantage of many new capabilities available in the API enhancements, such as the new Raster namespace, as well as many new community samples with ready-to-run solutions.
Also in 2017, new training resources became available with the early 2017 release of the instructor-led course, Extending ArcGIS Pro with Add-Ins, and the Pro SDK DevLabs were also made available. Many developers were able to attend Dev Summit and UC and take advantage of the many Pro SDK sessions and get updates from the SDK team and other ArcGIS Pro teams. We also saw excellent participation in the GeoNet Pro SDK Group, as more developers are finding their way to the group to collaborate, find resources and get their questions answered.
2017 also saw new Pro add-ins deployed in production workflows at several user organizations, and also new commercial add-ins from Esri Business Partners making their way onto the market. 2017 also brought new opportunities to distribute add-ins via the ArcGIS Marketplace.
Looking Ahead into 2018
Here in January, the ArcGIS Pro 2.1 EAC is wrapping up, with preparations underway for the final release. There will be plenty of new SDK functionality made available in 2018 with Pro 2.1 and Pro 2.2.
Pro SDK 2.1 highlights:
- Annotation – Create and edit annotation features
- Layout – Create new layouts and layout elements, and manage layout views and selections
- Metadata – Manage project item metadata
- Portal – Query portal and online for groups, folders, and content
- Utility Network – Create custom utility network tools, traces and workflows
Looking ahead to Pro 2.2 later this year, the teams are planning new SDK functionality for Metadata, Portal, Topology, and adding more UI controls.
The Layout Map Series add-in sample, coming at Pro 2.1:
In 2018, we’re very focused on helping more developers and organizations make their way forward in migrating ArcMap customizations to ArcGIS Pro. The upcoming functionality in Pro 2.1 makes it a great release to begin working with the Pro SDK. As always, we want your feedback on what your needs are.
Learning Opportunities
The following are some great Pro SDK learning opportunities available early this year:
- GeoDev Webinar – Building ArcGIS Pro SDK Add-Ins and Solution Configurations
- Instructor-led Pro SDK training – Extending ArcGIS Pro with Add-Ins
- Developer Summit – The best conference for Pro SDK training and updates
At Dev Summit, there will be many Pro SDK learning opportunities:
- Pre-Summit Hands-On Training –
Introduction to Programming with the ArcGIS Pro SDK for .NET
Just prior to the Dev Summit, this workshop is a great way to leverage your Dev Summit trip and get two full days of in-person, hands-on training with the Esri Training Services team.
- Technical sessions and demo theaters –
Search the Dev Summit agenda with keywords “Pro SDK” to quickly find the many sessions available throughout the week.
- Getting Started with the Pro SDK Workshop –
There will be a new 5-hour introductory hands-on workshop available this year during Dev Summit. Bring your own machine, pre-installed with ArcGIS Pro and Microsoft Visual Studio 2015 or 2017, and get started with the Pro SDK. The workshop will have lectures and exercises which introduce SDK concepts, helpful tips and practical steps to help you get started developing add-ins to extend ArcGIS Pro. As it’s offered during the Dev Summit week, no pre-registration is required.
We’ll have more information and updates on all these offerings as we get closer to Dev Summit.
Your Feedback
Again and as always, we encourage and invite your feedback on the Pro SDK. We’re always keen to hear what you want to see added to make your Pro customization experience better. Let us know, find out more and collaborate with others in the GeoNet Pro SDK Group.
Thank you for sharing your Pro development accomplishments with us in 2017. We look forward to seeing more of your great work and what you develop with ArcGIS Pro and the Pro SDK in 2018.
Commenting is not enabled for this article. | https://www.esri.com/arcgis-blog/products/announcements/announcements/arcgis-pro-extensibility-looking-back-and-ahead-into-2018/ | CC-MAIN-2021-31 | refinedweb | 904 | 52.9 |
Building a simple coverage based fuzzer for binary codexct
In this post I will walk through the process of creating a simple coverage based fuzzer. The code of this project is on available here. The general idea here is that you download the code and read this post to understand what it does on the more interesting parts so you are able to extend it or write your own fuzzer based on the concepts.
On a high level view the fuzzer takes one or more seed files, traces the program execution with the seeds as inputs and builds up a map of all paths seen within the program. It then generates new inputs that will be traced as well. If any of these new inputs generates coverage that has not been seen before it is added to the queue. Files in queue are combined and mutated to generate new inputs for the next round of fuzzing. This process is continued and aimed towards optimizing coverage.
For obtaining the necessary code coverage for our fuzzer many methods exist. The goal is to record (trace) which basic blocks are executed when the target program runs. AFL for example uses a custom version of qemu usermode to achieve this tracing, while hongfuzz supports several more recent methods, one of them being Intel Processor Trace, a hardware tracing feature of recent Intel CPUs (>= Skylake) that allows tracing with minimal overhead. While hardware tracing certainly is the most effective method, not everyone has a Intel CPU so at this point the fuzzer will be based on software tracing.
Dynamorio is a binary instrumentation framework that allows all kinds of manipulation and information gathering of running binaries. For obtaining coverage it already contains a tool we can use named
drcov.
To get started get and build dynamorio:
git clone cd dynamorio && mkdir build64 && cd build64 cmake .. make -j32
Obtaining coverage is fairly simple – you start
drrun with
drcov and tell it which binary to run:
~/dynamorio/build64/bin64/drrun -t drcov -dump_text -- objdump -d /usr/bin/id
This creates a file named
drcov.x86_64-linux-gnu-objdump.18410.0000.proc.log with the following contents:
... 4, 4, 0x00007f1477464000, 0x00007f147746b000, 0x00007f147746c2b0, 0000000000000000, /usr/bin/x86_64-linux-gnu-objdump 5, 4, 0x00007f147746b000, 0x00007f14774a0000, 0x00007f147746c2b0, 0000000000007000, /usr/bin/x86_64-linux-gnu-objdump 6, 4, 0x00007f14774a0000, 0x00007f14774b6000, 0x00007f147746c2b0, 000000000003c000, /usr/bin/x86_64-linux-gnu-objdump 7, 4, 0x00007f14774b7000, 0x00007f14774be000, 0x00007f147746c2b0, 00000000000523d0, /usr/bin/x86_64-linux-gnu-objdump 8, 8, 0x00007f147b494000, 0x00007f147b495000, 0x00007f147b495090, 0000000000000000, /usr/lib/x86_64-linux-gnu/ld-2.28.so 9, 8, 0x00007f147b495000, 0x00007f147b4b3000, 0x00007f147b495090, ... module[ 9]: 0x0000000000001090, 8 module[ 9]: 0x0000000000001e90, 85 module[ 9]: 0x0000000000001ee5, 64 module[ 9]: 0x0000000000001f43, 6 module[ 9]: 0x0000000000001f33, 16 ...
At the top you can see a list of loaded modules, showing an index, at which addresses they are loaded and their name. After the module section we see the actual basic blocks that have been executed with their addresses, relative to their module start. To use this in our fuzzer it is important to run the target binary via dynamorio and parse the results, which is done by the run_and_trace method.
... cmd = [dynamorioHOME+"/bin64/drrun", "-t", "drcov", "-dump_text","--"] for i in target.split(" "): cmd.append(i) proc = await asyncio.create_subprocess_exec(*cmd, stdout=asyncio.subprocess.PIPE) await proc.wait() ...
As shown before this runs the target and generates coverage data. The output is read back and module and basic block data are parsed via regexes into lists.
Now that we have obtained coverage a widely used approach is to create a map from it that records all edges in the program. The idea here is that programs can be viewed as graphs where the nodes are basic blocks and the transition between the basic blocks are edges.
We are going to follow the approach afl is using in this post, which is xoring the from and to address of two basic blocks together on a transition. Since we want to distribute the map entries evenly we first map the addresses to unique random values:
def store(self, addr): if addr not in self.bbs: self.bbs[addr] = random.randint(0, 0xFFFFFFFF) return self.bbs[addr] def get(self, num): for k, v in self.bbs.items(): if v == num: return self.bbs[k] assert(num in self.bbs.values())
Afterwards we xor them and store them in said map:
def update(self, addr1, addr2): cov = False addr1 = self.store(addr1) addr2 = self.store(addr2) e = addr1 ^ addr2 if e not in self.edges: cov = True self.edges[e] = 0 if self.verbose: print(" +Cov") else: self.edges[e] += 1 return cov
The whole point of it is to save information about which transitions are already known so new transitions can be recognized and treated accordingly.
As we can now trace executions with any input files it is time to think about how to create input files. There a various approaches on handling this – for this post I will use a simple genetic algorithm.
We select 2 random inputs from queue and combine them into one new input. To achieve this I loop through all of inputs bytes and choose a byte from on or the other parent while creating the child. This makes sure the new input has bytes from both parents. The following code snippet shows the generate method of the genetic input generator:
def generate(self): child = b'' # selection (choose parents) left = random.choice(self.samples) right = random.choice(self.samples) # crossover length = random.choice([len(left),len(right)]) for i in range(length): coin = random.randint(0,1) if coin == 0 and len(left) >= i: child += left[i:i+1] elif coin == 1 and len(right) >= i: child += right[i:i+1] else: if len(left) > len(right): child += left[i:i+1] else: child += right[i:i+1] # mutate length (and fill with random bytes) multiplier = random.uniform(1.0, 2.0) length = int(length * multiplier) # random mutation mutated = b'' for i in range(length): coin = random.randint(0, 100) if coin < self.mutation_rate: # n % chance mutated += os.urandom(1) else: mutated += child[i:i+1] child = mutated return child
Compared to other coverage driven fuzzers this one is very slow because it is written in python, doesn’t optimize process loading and various other reasons. If you want to write a productive one I suggest to look into the technical details of AFL – speed is essential when fuzzing. This concludes this post – feel free to reach out for questions, ideas or feedback. | https://www.vulndev.io/2019/06/22/building-a-simple-coverage-based-fuzzer-for-binary-code/ | CC-MAIN-2022-40 | refinedweb | 1,084 | 63.49 |
The
javap tool is one of the JDK tools used to disassemble class files. The benefits of using this tool is to understand how the compiler deals with our code in case we have doubts about some of the micro-optimization techniques.
The syntax of the tool is as follows:
javap [options] <classes>
We can add many classes and separate them using spaces. The most important options are as follows:
ACC_PUBLIC)
-l: This option is to print line and local variable tables
-public: This option is to show only public classes and members
-protected: This option is to show only protected and public classes and members
-package: This option is ...
No credit card required | https://www.oreilly.com/library/view/java-ee-7/9781782176428/ch11s04.html | CC-MAIN-2018-51 | refinedweb | 114 | 57 |
Greetings,
Well, I spend a whole afternoon trying to implement a simple navigation system using vectors. Finally it worked, here's a fragment of what I did (from a Spaceship class):
def moveForward(self): self.center -= self.step * Vector2D(1,0).rotate(self.angle).invX() self.rect.center = self.center.toPoint()
Basically, I use right and left arrow keys to rotate the spaceship to right or left direction, respectly. And, I have the previous fragmente code to move forward. Due the fact that (0,0) grows from left to right (x-coordinate) and from top to bottom, I have to invert the x-coordinate (invX() method) from the rotated vector in order to "correct" the spaceship navigation. Is there another way to make this simpler, for example, changing the origin or somewhat like that?
Thank you | http://www.gamedev.net/topic/638173-simplify-reference-system-and-vector-movement/ | CC-MAIN-2015-32 | refinedweb | 136 | 51.38 |
, LOAD and Ajax.
LOAD_post', signature
The full signature of the LOAD helper is the following:
LOAD(c=None, f='index', args=[], vars={}, extension=None, target=None, ajax=False, ajax_trap=False, url=None,user_signature=False, timeout=None, times=1, may or may not be created with web2py).
user_signaturedefaults to False but, if you are logged in, it should be set to True. This will make sure the ajax callback is digitally signed. This is documented in chapter 4...
Redirect from a component
To redirect from a component, use this:
redirect(URL(...),client_side=True)
but note that the redirected URL will default to the extension of the component. See notes about the argument
extension in the URL function in Chapter 4
Reload page via redirect after component submission
If you call an action via Ajax and you want the action to force a redirect of the parent page you can do it with a redirect from the LOADed controller function. If you want to reload the parent page, you can redirect to it. The parent URL is known (see Client-Server component communications )
so after processing the form submit, the controller function reloads the parent page via redirect:
if form.process().accepted: ... redirect( request.env.http_web2py_component_location,client_side=True)
Note that the section below, Client-Server component communications, describes how the component can return javascript, which could be used for more sophisticated actions when the component is submitted. The specific case of reloading another component is described next.
Reload another component
If you use multiple components on a page, you may want the submission of one component to reload another. You do this by getting the submitted component to return some javascript.
It's possible to hard-code the target DIV, but in this recipe we use a query-string variable to inform the submitting-controller which component we want to reload. It's identified by the id of the DIV containing the target component. In this case, the DIV has id 'map'. Note that it is necessary to use
target='map' in the LOAD of the target; without this, the target id is randomised and reload() won't work. See LOAD signature above.
In the view, do this:
{{()
For more information about response.js see Client-Server component communications (below).
Ajax post does not support multipart forms.
LOAD and and the A Helper helper ._1<<
plugin_comments and we make it better. We want to be able to customize: = _()
Notice how all the code except the table definition is encapsulated in a single function called
_ so that it does not pollute the global namespace. repositories, plugin install via admin
While there is no single repository of web2py plugins you can find many of them at one of the following URLs: (this is the leading repository and is integrated to the web2py admin application for one-click installs)
Recent versions of web2py admin allow automatic fetch and install of plugins from web2pyslices. To add a plugin to an app, edit it via the admin application, and choose Download Plugins, currently at the bottom of the screen.
To publish your own plugins, make an account at web2pyslices.
Here is a screenshot showing some of the auto-installable plugins:
| http://web2py.com/book/default/chapter/12 | CC-MAIN-2014-41 | refinedweb | 535 | 53.92 |
Today when I was visiting a website and wanted to take a screenshot, I pressed Shift+Print Screen. Then I changed my mind and right-clicked the mouse to cancel the screenshot. After I did this, however, the gnome-shell collapsed and there came out a notification asking me to send messages to ubuntu. A moment later the gnome-shell restarted again. So I tried again the operations described above and the same thing happened, except that gnome-shell didn't restart at this time. What was worse, I couldn't input via my keyboard any more! That means I couldn't restart my computer in the terminal. So I used tty2 to restart and reported the problem here, wondering if this is a bug? Or the conflict with other programs? The distribution I use is Ubuntu 12.04.1, and the gnome-shell's version is 3.4.1.
Hope my messages do some help. Thank you for reading!
Question information
- Language:
- English Edit question
- Status:
- Answered
- Assignee:
- No assignee Edit question
- Last query:
- 2012-09-19
- Last reply:
- 2012-09-19
I'm sorry that I'm a freshman here and I don't know how to reply a user. These are words replied to actionparsnip (andrew-
Is the command you mentioned a way to take a full screenshot? I have tried the command at the terminal and it asked me to install imagemagick. If the command is just for a screenshot, it's totally unnecessary as the screenshot I'm using is enough, ignoring the unusual phenomenon I can hardly meet in daily use. If not, what should I do then? I don't quite understand CLI although I had google for it, and I don't know whether the terminal at ubuntu is a part of it.
Whatever, thank you for your answer. XD
Try scrot or imagemagick at CLI with:
import ~/Screenshot.png
Sounds like a bug to me | https://answers.launchpad.net/ubuntu/+source/gnome-shell/+question/208962 | CC-MAIN-2019-22 | refinedweb | 324 | 74.69 |
Doubleclick on delimiter
The idea is simple: After double clicking on the delimiter, the text is selected to another delimiter.
If someone liked it, I ask you to support the idea with your posts, which would show the developers the importance of the feature.
- Scott Sumner last edited by Scott Sumner
Keyboard is easier (trying to double click a single character with a smallish font turns it into a video game).
Keyboard Ctrl+Alt+B
If you truly like the mouse option, you could replicate this behavior with a scripting plugin, e.g. Pythonscript.
It’s not a problem. And we can use the keyboard.
But it seems to me that such behavior is natural.
If you double-click on a word, it becomes highlighted.
If you double-click on the parenthesis, what is between the parenthesis becomes highlighted.
It will be convenient if this becomes the native behavior of the program.
- Scott Sumner last edited by
So purely for fun, here’s the Pythonscript version:
def callback_sci_DOUBLECLICK(args): ap = args['position'] if editor.getTextRange(ap, ap) in '([{}])': notepad.menuCommand(43053) editor.callback(callback_sci_DOUBLECLICK, [SCINTILLANOTIFICATION.DOUBLECLICK])
@Scott-Sumner said:
So purely for fun, here’s the Pythonscript version
And it’s all? Only four lines?
In this case, the developers really need to include this feature in the program.
Now a double click on the delimiter has no reasonable behavior.
Currently, if you
Ctrl+Double Clickanywhere inside the delimiter pair it selects everything inside.
Currently, if you
Ctrl+Double Clickanywhere inside the delimiter pair it selects everything inside.
This is a nice feature! Thanks for the tip!
But the current implementation of the feature has two weaknesses.
- If there are several lines between delimiters, the feature does not work.
- Delimeters are not selected at the beginning and end (Ctrl+Alt+B does this).
So, it would be useful to add to the current implementation double click on the delimiter.
- If there are several lines between delimiters, the feature does not work.
Settings > Preferences > Delimiter > Allow on several lines
- Delimeters are not selected at the beginning and end (Ctrl+Alt+B does this).
You are correct. In most cases I find I don’t want the delimiters selected (for example selecting all the parameters within a function call) but under some cases (such as yours) I do see it helpful to have the delimiters selected as well.
- Scott Sumner last edited by
Maybe worth pointing out that the Ctrl + double-left-click method only works for ONE type of delimiter (whatever is configured in the Delimiter preferences). The Pythonscript method handles several types, specifically
{ },
[ ]and
( ).
Settings > Preferences > Delimiter > Allow on several lines
It solves almost all problems!
In this case, we only need an option that sets whether to select delimiters or not.
Of course Scott is right, delimiters should be assigned to the current language. Or at an additional setting.
And further. It would be nice to have [ctrl + alt + b] work anywhere between the parentheses (like dblclck + ctrl). In this case, if you press [ctrl + alt + b] several times, the selection should expand to the next and next delimiters. | https://community.notepad-plus-plus.org/topic/15265/doubleclick-on-delimiter | CC-MAIN-2021-17 | refinedweb | 520 | 57.57 |
perlglossary - Perl Glossary, explained clearly enough.
The sort of characters we put into words. In Unicode, this is all letters including all ideographs and certain diacritics, letter numbers like Roman numerals, and various combining marks..
Used to describe a referent that is not directly accessible through a named variable. Such a referent must be indirectly accessible through at least one hard reference. When the last hard reference goes away, the anonymous referent is destroyed without pity.
A bigger, fancier sort of program with a fancier name so people don’t realize they are using a program...
The open source license that Larry Wall created for Perl, maximizing Perl’s usefulness, availability, and modifiability. The current version is 2. ()..
See hash. Please. The term associative array is the old Perl 4 term for a hash. Some languages call it a Camel chapter 13, “Overloading”.. the section “The Little Engine That /Couldn(n’t)” in Camel chapter 5, “Pattern Matching”.. the
bless function in Camel chapter 27,
“Functions”..
A syntactic construct consisting of a sequence of Perl statements that is delimited by braces.
The
if and
while statements are defined in terms of
BLOCKs,
for instance.
Sometimes we also say “block” to mean a lexical scope; that is,
a sequence of statements that actsC
A function that is predefined in the language.
Even when hidden by overriding,
you can always get at a built- in function by qualifying its name with the
CORE:: pseudopackage.
A group of related modules on CPAN. (Also sometimes refers to a group of command-line switches grouped into one switch cluster.)
A piece of data worth eight bits in most places...
A data repository. Instead of computing expensive answers several times, compute it once and save the result.
A handler that you register with some other part of your program in the hope that the other part of your program will trigger your handler when some event of interest transpires..
Reduced to a standard form to facilitate comparison.
The variables—such as
$1 and
$2,
and
%+ and
%– —that hold the text remembered in a pattern match.
See Camel chapter 5,
“Pattern Matching”.
The use of parentheses around a subpattern in a regular expression to store the matched substring as a backreference. (Captured strings are also returned as a list in list context.) See Camel chapter 5, “Pattern Matching”.
Copying and pasting code without understanding it, while superstitiously believing in its value. This term originated from preindustrial cultures dealing with the detritus of explorers and colonizers of technologically advanced cultures. See The Gods Must Be Crazy..
Comparing or matching a string case-insensitively.
In Perl,
it is implemented with the
/i pattern modifier,
the
fc function,
and the
\F double-quote translation escape.
The process of converting a string to one of the four Unicode casemaps; in Perl,
it is implemented with the
fc,
lc,
ucfirst,
and
uc functions.
The smallest individual element of a string. Computers store characters as integers, but Perl lets you operate on them as text. The integer used to represent a particular character is called that character’s codepoint.
A square-bracketed list of characters used in a regular expression to indicate that any character of the set may occur at a given point. Loosely, any predefined set of characters so used.
A predefined character class matchable by the
\p or
\P metasymbol.
Unicode defines hundreds of standard properties for every possible codepoint,
and Perl defines a few of its own,. Also see instance method.
In networking, a process that initiates contact with a server process in order to exchange data and perhaps receive a service..
A regular expression subpattern whose real purpose is to execute some Perl code—for example,
the
(?{...}) and
(??{...}) subpatterns.
The order into which characters sort. This is used by string comparison routines to decide, for example, where in this glossary to put “collating sequence”.
A person with permissions to index a namespace in PAUSE. Anyone can upload any namespace, but only primary and co-maintainers get their contributions indexed...
The values you supply along with a program name when you tell a shell to execute a command.
These values are passed to a Perl program file (or string,
in the case of
eval) that is currently being compiled.
The process of turning source code into a machine-usable form. See compile phase.
Any time before Perl starts running your main program.
See also run phase.
Compile phase is mostly spent in compile time,
but may also be spent in runtime when
BEGIN blocks,
use or
no declarations,
or constant subexpressions are being evaluated.
The startup and import code of any
use declaration is also run during compile phase. Camel chapter 16, “Compiling”.
The time when Perl is trying to make sense of your code, as opposed to when it thinks it knows what your code means and is merely trying to do what it thinks your code says to do, which is runtime. the section “Creating References” in Camel chapter 8, “References”., or subroutine that composes, initializes, blesses, and returns an object. Sometimes we use the term loosely to mean a composer.)..
The corpse of a process, in the form of a file left in the working directory of the process, usually as a result of certain kinds of fatal errors.
The Comprehensive Perl Archive Network. (See the Camel Preface and Camel chapter 19, “CPAN” for details.)
The typical C compiler’s first pass,
which processes lines beginning with
# for conditional compilation and macro definition,
and does various manipulations of the program text based on the current definitions.
Also known as cpp(1).
Someone who breaks security on computer systems. A cracker may be a true hacker or only a script kiddie.
The last filehandle that was designated with
select(FILEHANDLE);
STDOUT,
if no filehandle has been selected.
The package in which the current statement is compiled. Scan backward in the text of your program through the current lexical scope or any enclosing lexical scopes until you find a package declaration. That’s your current package name.
See working directory.
In academia,
a curriculum vitæ,
a fancy kind of résumé.
In Perl,
an internal “code value” typedef holding a subroutine.
The
CV type is a subclass of SV.
A bare,
single statement,
without any braces,
hanging off an
if or
while conditional.
C allows them.
Perl doesn’t.
A packet of data, such as a UDP message, that (from the viewpoint of the programs involved) can be sent independently over the network. (In fact, all packets are sent independently at the IP level, but stream protocols such as TCP hide this from your program.)
How your various pieces of data relate to each other and what shape they make when you put them all together, as in a rectangular table or a triangular tree.
A set of possible values,
together with all the operations that know how to deal with those values.
For example,
a numeric data type has a certain set of numbers that you can work with,
as well.
Stands for “Database.
Something that tells your program what sort of variable you’d like.
Perl doesn’t require you to declare variables,
but you can use
my,
our,
or
state to denote that you want something other than the default.
To subtract a value from a variable,
as in “decrement
$x” (meaning to remove 1 from its value) or “decrement
$x by 3”.
A value chosen for you if you don’t supply a value of your own. the
defined entry in Camel chapter 27,
“Functions”..
A pod directive. See Camel chapter 23, “Plain Old Documentation”.
A special file that contains other files. Some operating systems call these “folders”, “drawers”, “catalogues”, or “catalogs”.
A name that represents a particular instance of opening a directory to read it,
until you close it.
See the
opendir function.
Some people need this and some people avoid it. For Perl, it’s an old way to say I/O layer..
A standard, bundled release of a system of software. The default usage implies source code is included. If that is not the case, it will be called a “binary-only” distribution.
Some modules live both in the Standard Library and on CPAN. These modules might be developed on two tracks as people modify either version. The trend currently is to untangle these situations.
An enchantment, illusion, phantasm, or jugglery. Said when Perl’s magical dwimmer effects don’t do what you expect, but rather seem to be the product of arcane dweomercraft, sorcery, or wonder working. [From Middle English.] runtime..
The veil of abstraction separating the interface from the implementation (whether enforced or not), which mandates that all access to an object’s state be through methods alone.
See little-endian and big-endian.
When you change a value as it is being copied. [From French “in passing”, as in the exotic pawn-capturing maneuver in chess.].
See status.
Used as a noun in this case, this refers to a known way to compromise a program to get it to do something the author didn’t intend. Your task is to write unexploitable programs...
A spoonerism of “creeping featurism”, noting the biological urge to add just one more feature to a program.”. “wildcard” match on filenames.
See the
glob function..
One name for a file.
This name is listed in a directory.
You can use it in an
open to tell the operating system exactly which file you want to open,
and associate the file with a filehandle,
which will carry the subsequent identity of that file in your program,
until you close it. built-in unary operator that you use to determine whether something is true about a file,
such as
–o $filename to test whether you’re the owner of the file.
A program designed to take a stream of input and transform it into a stream of output.
The first PAUSE author to upload a namespace automatically becomes the primary maintainer for that namespace. The “first come” permissions distinguish a primary maintainer who was assigned that role from one who received it automatically.).
Sometimes informally used to refer to certain regex modifiers..
The act of emptying a buffer, often before it’s full.
Far More Than Everything You Ever Wanted To Know. An exhaustive treatise on one narrow topic, something of a super-FAQ. See Tom for far more..
To create a child process identical to the parent process at its moment of conception, at least until it gets ideas of its own. A thread with protected memory.
The generic names by which a subroutine knows its arguments.
In many languages,
formal arguments are always given individual. “Global Declarations” in Camel chapter 4,
“Statements and Declarations”. Perl calls when your program needs to respond to some internal event, such as a signal, or an encounter with an operator subject to operator overloading. See also callback..
A data structure used internally by Perl for implementing associative arrays (hashes) efficiently. See also bucket. Camel chapter 27,
“Functions”.
(Header files have been superseded by the module mechanism.) 15 are customarily represented by the letters
a through
f.
Hexadecimal constants in Perl start with
0x.
See also the
hex function in Camel chapter 27,
“Functions”..)
The computer on which a program or other data resides.
Excessive pride, the sort of thing for which Zeus zaps Camel chapter 27,
“Functions”.
To increase the value of something by 1 (or by some other number, if so specified). function merely locates the position (index) of one string in another.
An expression that evaluates to something that can be used as a filehandle: a string (filehandle name), a typeglob, a typeglob reference, or a low-level IO object.
If something in a program isn’t the value you’re looking for but indicates where the value is, that’s indirection. This can be done with either symbolic references or hard.
In English grammar,
a short noun phrase between a verb and its direct object indicating the beneficiary or recipient of the action.
In Perl,
print STDOUT "$foo\n"; can be understood as “verb indirect-object object”,
where
STDOUT is the recipient of the
"$foo" is the object being printed.
Similarly,
when invoking a method,
you might place the invocant in the dative slot between the method and its arguments:
$gollum = new Pathetic::Creature "Sméagol"; give $gollum "Fisssssh!"; give $gollum "Precious!";";.
See instance variable.. runtime system then interprets. to do what you think it’s supposed to do. We usually “call” subroutines but “invoke” methods, since it sounds cooler.
Input from, or output to, a file or device.
An internal I/O object. Can also mean indirect object.
One of the filters between the data and what you get as input or what you end up with as output.
India Pale Ale. Also the International Phonetic Alphabet, the standard alphabet used for phonetic notation worldwide. Draws heavily on Unicode, including many combining characters.ET signatures.
The string index to a hash, used to look up the value associated with that key.
See reserved words.
A name you give to a statement so that you can talk about that statement elsewhere in the program.newline characters terminated with a newline character. On non-Unix machines, this is emulated by the C library even if the underlying operating system has different ideas.
A grapheme consisting of either a carriage return followed by a line feed or any character with the Unicode Vertical Space character property.
Used by a standard I/O output stream that flushes its buffer after every newline. Many standard I/O libraries automatically set up line buffering on output that is going to the terminal..
Used as a noun, a name in a directory that represents..
In Unicode, not just characters with the General Category of Lowercase Letter, but any character with the Lowercase property, including Modifier Letters, Letter Numbers, some Other Symbols, and one Combining Mark. ASCII Camel chapter 12, “Objects”.
The path Perl takes through
@INC. By default, this is a double depth first search, once looking for defined methods and once for
AUTOLOAD. However, Perl lets you configure this with
mro.
A CPAN mirror that includes just the latest versions for each distribution, probably created with
CPAN::Mini. See Camel chapter 19, “CPAN”.
The belief that “small is beautiful”. Paradoxically, if you say something in a small language, it turns out big, and if you say it in a big language, it turns out small. Go figure.
In the context of the stat(2) syscall, refers to the field holding the permission bits and the type of the file.
See statement modifier, regular expression, and lvalue,”.
Short for one member of Perl mongers, a purveyor of Perl.
A temporary value scheduled to die when the current statement finishes.
See method resolution order.
An array with multiple subscripts for finding a single element. Perl implements these using references—see Camel chapter 9, “Data Structures”.
The features you got from your mother and father, mixed together unpredictably. (See also inheritance and single inheritance.) In computer languages (including Perl), it is.
Not a number. The value Perl uses for certain invalid or inexpressible floating-point operations.
The most important attribute of a socket, like your telephone’s telephone number. Typically an IP address. See also port.
A single character that represents the end of a line, with the ASCII value of 012 octal under Unix (but 015 on a Mac), and represented by
\n in Perl strings. For Windows machines writing text files, and for certain physical devices like terminals, the single newline gets automatically translated by your C library into a line feed and a carriage return, but normally, no translation is done.
Network File System, which allows you to mount a remote filesystem as if it were local.
Converting a text string into an alternate but equivalent canonical (or compatible) representation that can then be compared for equivalence. Unicode recognizes four different normalization forms: NFD, NFC, NFKD, and NFKC.
A character with the numeric”.
See either switches or regular expression modifiers.
An abstract character’s integer value. Same thing as codepoint.
Giving additional meanings to a symbol or construct. Actually, all languages do overloading to one extent or another, since people are good at figuring out things from context. the section “Overriding Built-in Functions” in Camel chapter 11, “Modules”), and to describe how you can define a replacement method in a derived class to hide a base class’s method of the same name (see Camel chapter 12, “Objects”)..
The Perl Authors Upload SErver (), the gateway for modules on their way to CPAN.
A Perl user group, taking the form of its name from the New York Perl mongers, the first Perl user group. Find one near you at...
The markup used to embed documentation into your Perl code. Pod stands for “Plain old documentation”. See Camel chapter 23, “Plain Old Documentation”.
A sequence, such as
=head1, that denotes the start of a pod section.).
The notion that you can tell an object to do something generic, and the object will interpret the command in different ways depending on its type. [< Greek πολυ- + μορϕή, many forms.], such as a mobile home or London Bridge.
Someone who “carries” software from one platform to another. Porting programs written in platform-dependent languages such as C can be difficult work, but porting programs like Perl is very much worth the agony.
Said of quantifiers and groups in patterns that refuse to give up anything once they’ve gotten their mitts on it. Catchier and easier to say than the even more formal nonbacktrackable..
The author that PAUSE allows to assign co-maintainer permissions to a namespace. A primary maintainer can give up this distinction by assigning it to another PAUSE author. See Camel chapter 19, “CPAN”.
A subroutine..
See script.
A system that algorithmically writes code for you in a high-level language. See also code generator.
Pattern matching matching>that picks up where it left off before.
See either instance variable or character property.
In networking, an agreed-upon way of sending messages back and forth so that neither correspondent will get too confused..)
A construct that sometimes looks like a function but really isn’t. Usually reserved for lvalue modifiers like
my, for context modifiers like
scalar, and for the pick-your-own-quotes constructs,
q//,
qq//,
qx//,
qw//,
qr//,
m//,
s///,
y///, and
tr///.
Formerly, a reference to an array whose initial element happens to hold a reference to a hash. You used to be able to treat a pseudohash reference as either an array reference or a hash reference. Pseduohashes are no longer supported.
An operator X
that looks something like a literal, such as the output-grabbing operator, <literal moreinfo="none"`> Camel chapter 5, “Pattern Matching”.
An option on a pattern or substitution, such as
/i to render the pattern case- insensitive..
A name for a concrete set of behaviors. A role is a way to add behavior to a class without inheritance.
The superuser (
UID == 0). Also the top-level directory of the filesystem.
What you are told when someone thinks you should Read The Fine Manual.
Any time after Perl starts running your main program. See also compile phase. Run phase is mostly spent in runtimeanalyzed each time the pattern match operator is evaluated. Runtime walled off area that’s not supposed to affect beyond its walls. You let kids play in the sandbox instead of running in the road. See Camel chapter 20, “Security”..
From how far away you can see a variable,.
The area in which a particular invocation of a particular file or subroutine keeps some of its temporary values, including any lexically scoped variables. glyph used in magic. Or, for Perl, the symbol in front of a variable name, such as
$,
@, and
%.
A bolt out of the blue; that is, an event triggered by the operating system, probably when you’re least expecting it. the
%SIG hash in Camel chapter 25, “Special Names” and the section “Signals” in Camel chapter 15, “Interprocess Communication”. output> filehandle
STDERR. You can use this stream explicitly, but the
die and
warn built-ins write to your standard error stream automatically (unless trapped or otherwise intercepted).
The default input stream for your program, which if possible shouldn’t care where its data is coming from. Represented within a Perl program by the filehandle
STDIN.
A standard C library for doing buffered input and output to the operating system. (The “standard” of standard I/O is at.
Everything that comes with the official perl distribution. Some vendor versions of perl change their distributions, leaving out some parts or including extras. See also dual-lived.
The default output stream for your program, which if possible shouldn’t care where its data is going. Represented within a Perl program by the filehandle
STDOUT...
If you’re a C or C++ programmer, you might be looking for Perl’s
state keyword.
No such thing. See class method.
No such thing. See lexical scoping.
No such thing. Just use a lexical variable in a scope larger than your subroutine, or declare it with
state instead of with
my.
A special internal spot in which Perl keeps the information about the last file on which you requested information. Camel chapter 27, “Functions”..
given. See “The
given statement” in Camel chapter 4, “Statements and Declarations”.
Generally, any token or metasymbol. Often used more specifically to mean the sort of name you might find in a symbol table.. σύνταξις, “with-arrangement”. How things (particularly symbols) are put together with each other.
An internal representation of your program wherein lower-level constructs dangle off the higher-level constructs enclosing them. say “syscall” for something you could call indirectly via Perl’s
syscall function, and never for something you would call with Perl’s
system function.
The special bookkeeping Perl does to track the flow of external data through your program and disallow their use in system commands.
Said of data derived from the grubby hands of a user, and thus unsafe for a secure program to rely on. Perl does taint checks if you run a setuid (or setgid) program, or if you use the
–T switch.
Running under the
–T switch, marking all external data as suspect and refusing to use it with system commands. See Camel chapter 20, “Security”.. one another.
The bond between a magical variable and its implementation class. See the
tie function in Camel chapter 27, “Functions” and Camel chapter 14, “Tied Variables”...
The thing you’re working on. Structures like
while(<>),
for,
foreach, and
given set the topic for you by assigning to
$_, the default (topic) variable. type definition in the C and C++ languages.
A lexical variable lexical>that is declared with a class type:
my Pony $bill.
Use of a single identifier, prefixed with
*. For example,
*name stands for any or all of
$name,
@name,
%name,
&name, or just
name. How you use it determines whether it is interpreted as all or only one of them. See “Typeglobs and Filehandles” in Camel chapter 2, “Bits and Pieces”...
In Unicode, not just characters with the General Category of Uppercase Letter, but any character with the Uppercase property, including some Letter Numbers and Symbols. Not to be confused with titlecase.
An actual piece of data, in contrast to all the variables, references, keys, indices, Camel chapter 27, “Functions” and the
warnings pragma in Camel chapter 28, “Pragmantic Modules”.
An expression which, when its value changes, causes a breakpoint in the Perl debugger.
A reference that doesn’t get counted normally. When all the normal references to data disappear, the data disappears. These are useful for circular references that would never disappear otherwise. extension language called (exasperatingly) XS.
An external subroutine defined in XS.
Yet Another Compiler Compiler. A parser generator without which Perl probably would not have existed. See the file perly.y in the Perl source distribution.
A subpattern assertion matching the null string between characters.. | http://search.cpan.org/~llap/perlfaq-5.0150044/lib/perlglossary.pod | CC-MAIN-2015-40 | refinedweb | 4,006 | 58.69 |
Define resources in Azure Resource Manager templates
When creating Resource Manager templates, you need to understand what resource types are available, and what values to use in your template. The Resource Manager template reference documentation simplifies template development by providing these values.
If you are new to working with templates, see Quickstart: Create and deploy Azure Resource Manager templates by using the Azure portal for an introduction to working with templates.
To determine locations that available for a resource type, see Set location in templates. To add tags to resources, see Tag resources in Azure Resource Manager templates.
If you know the resource type, you can go directly to it with the following URL format:{provider-namespace}/{resource-type}. For example, the SQL database reference content is available at:
The resource types are located under the Reference node. Expand the resource provider that contains the type you are looking for. The following image shows the types for Compute.
Or, you can filter the resource types in navigation pane:
| https://docs.microsoft.com/ja-jp/azure/templates/ | CC-MAIN-2019-51 | refinedweb | 168 | 54.83 |
I'm using Max OS X 10.10.3, and I finally got the
graphics.py to show in Python 3, before it was saying no module existed.
However, now when I try
import graphics, or
from graphics import *, I get the message:
"source code string cannot contain null bytes"
Does any Mac user (using Python 3) perhaps know what is wrong? Has anyone used the Zelle book and his
graphics.py module? Thanks.
For posterity: I had the same problem and fixed it using,
sed -i 's/\x0//g' FILENAME
The file seemed to be messed up in numerous ways (wrong endings, etc); no idea how...
See
I just encountered this problem, which is usually caused by the encoding format. You can use Notepad++ to change the encoding format of python files to UTF-8.
Open your file with an editor that can show you all invisible character. You will see where is the invalid char, just delete and re-type it.
If you are on mac you can do it with Coda > Open your file > Show invisible characters.
I've got the same error and the solution is to uninstall the Library and if you can't simply delete it and reinstall the Library. should work it has work for me...
I am using Visual Studio Code, the encoding was set to UTF-16 LE. You can check the encoding on the right bottom side of VSCode. Just click on the encoding and select "save with encoding" and select UTF-8. It worked perfectly.
- Go to python folder
python36/Lib/site-packages/scipy/
- Open
__init__.py
Change:
from scipy._lib._testutils import PytestTester
to:
from scipy._lib.test__testutils import PytestTester
It worked on my windows 7
I got this message when I wanted to use
eval for my input for my function that sometimes it takes string or int/float but when it takes
numpy numbers, it throws this exception,
eval(number).
My solution was
eval(str(number)).
This kind of error is not from your project source code. This kind of error emerges from your python interpreter. So the best solution is to set your python interpreter in your project env directory. or set the interpreters virtual env properly using your IDE's interpreter configuration.
来源： | https://www.tfzx.net/article/916704.html | CC-MAIN-2020-34 | refinedweb | 379 | 74.69 |
Hello everyone,
I am working on a project where I have to automate the process of entering data through a website. I decided to use the WebBrowser control in .NET for this task.
The problem I am having is that when I try to click on certain buttons, nothing happens. After lookign at the HTML code, I saw a pattern. I can click on buttons where the input type is submit, but I have trouble with the buttons where input type is button and they only have an onclick attribute with javascript code.
I have also tried to use the InvokeScript() method, but that also does not work.
The only think I can think of is that JavaScript is disabled for the WebBrowser control.
Can anyone give me any ideas on how I might be able to resolve this issue?
WebBrowser control is the wrong approach. Trust me, I know. Did something similar to autoamtically fill a range of textboxes on a webpage. Have a look into the SHDocVw and the mshtml namespaces / libraries. Add a reference to them. ShDocVw you can find at :
C:\Windows\System32
And the mshtml you can find at :
C:\Program Files\Microsoft.NET\Primary InterOp Assemblies
Also include your using statements to reference these libraries.
Once done, you can manipulate the webpage ( HTMLDocument ) object through code.
All my Articles
Hannes
I have heard of MSHTML, but what is SHDocVw?
Here is a nice article giving you more details :
Forum Rules | http://forums.codeguru.com/showthread.php?515003-How-to-find-regex-expression-for-a-string&goto=nextnewest | CC-MAIN-2017-04 | refinedweb | 246 | 75.61 |
1. Download and install SharpDevelop. SharpDevelop is a free and open-source development environment for Microsoft .NET. As of this writing, the latest installer is available at the URL ““.
2. Download ServiceStack. ServiceStack is an open-source framework for implementing REST services. As of this writing, the latest versions of the .dlls are available in an archive file of sample code named “ServiceStack.Examples-master.zip” at the URL ““. Note that the ServiceStack site itself recommends using the NuGet package manager built into Visual Studio to get ServiceStack instead.
3. Extract the downloaded .zip file into any convenient location, then navigate down into the “lib” folder and locate the ServiceStack .dll files within it.
4. Start SharpDevelop.
5. Select the item “Main – New – Solution” from SharpDevelop’s main menu bar. The “New Project” dialog will appear.
6. In the “Categories” pane of the New Project dialog, select the tree item “C# – Windows Applications”. The contents of the “Templates” pane will change to display the available template types.
7. In the Templates pane, click the item named “Console Application” to select it.
8. In the Name box, enter the value “ServiceStackHelloWorldService”.
9. Click the Create button. The New Project dialog will be dismissed, focus will return to the main SharpDevelop window, and the structure of the newly created solution will be displayed in the “Projects” pane that (by default) is docked on the left side of the window.
10. Right click the node for the ServiceStackHelloWorldService project (not the node for the solution of the same name, which is its parent) and select the “Add Reference” item from the menu that appears. The “Add Reference” dialog will appear.
11. On the Add Reference dialog, click the tab named “.NET Assembly Browser”, then the “Browse” button. A Windows Explorer dialog titled “Open” will appear.
12. In the Open dialog, select the ServiceStack .dlls which were located in a previous step and then click the “Open” button. The Open dialog will be dismissed and focus will return to the Add Reference dialog, where the specified .dlls will be listed in the “Selected References” pane.
13. Click the OK button the Add Reference dialog to dismiss it and add the specified references to the project. Focus will return to the main SharpDevelop window.
14. Replace the automatically-generated contents of the Program.cs file with the text below and save. Note that this code is very minimally adapted from a sample found at the URL ““.
using System; using ServiceStack.ServiceInterface; using ServiceStack.WebHost.Endpoints; class Program { // This code is minimally adpated from a sample found at the URL // "".HostHttpListenerBase { public AppHost() : base("StarterTemplate HttpListener", typeof(HelloService).Assembly) { } public override void Configure(Funq.Container container) { Routes.Add("/hello"); Routes.Add("/hello/{Name}"); } } //Run it! static void Main(string[] args) { var listeningOn = args.Length == 0 ? "http://*:1337/" : args[0]; var appHost = new AppHost(); appHost.Init(); appHost.Start(listeningOn); Console.WriteLine("AppHost Created at {0}, listening on {1}", DateTime.Now, listeningOn); Console.ReadKey(); } }
15. Build and execute the application by selecting the “Project – Run Project” item from the main menu bar, or by pressing the F5 key. The code will be compiled, and a console window will appear that displays the message “AppHost Created at [current date and time], listening on http://*:1337“.
16. Open a web browser and navigate to the URL ““. A web page that contains the text, “Hello, world!” will be loaded.
Notes
- You could obviously also use Visual Studio for this, if you’d like. Or maybe even MonoDevelop.
The type or namespace name ‘Service’ could not be found (are you missing a using directive or an assembly reference?) Same for AppHostHttpListenerBase and Funq.
You need to add the references to the project: ServiceStack, ServiceStack.Interfaces, ServiceStack.ServiceInterface (with ServiceStack v3 it worked)
This helped me greatly, thanks ! Here is what I’m using (ServiceStack v3): | https://thiscouldbebetter.wordpress.com/2013/08/07/a-hello-world-service-in-servicestack-and-net-using-sharpdevelop/ | CC-MAIN-2017-13 | refinedweb | 643 | 60.51 |
Work at SourceForge, help us to make it a better place! We have an immediate need for a Support Technician in our San Francisco or Denver office.
1. As you've discovered, if validation=strict is specified, then doc() will
fail if the document cannot be validated against the schema, and
doc-available() will return false.
2. You may be able to get better diagnostics by using the -TF option (trace
external functions). The message "Failed to load document" is returned when
the external URI resolver returns null.
Regards,
Michael Kay
> -----Original Message-----
> From: Steven Ericsson-Zenith [mailto:steven@...]
> Sent: 09 September 2009 07:49
> To: Mailing list for the SAXON XSLT and XQuery processor
> Subject: Re: [saxon] oxygen: uri in doc and document functions
>
>
> And just so that I am clear. In this case, the target
> document was valid, the schema contained a newly introduced error.
>
> Steven
>
>
> On Sep 8, 2009, at 11:42 PM, Steven Ericsson-Zenith wrote:
>
> > Dear George,
> >
> > Okay, I am on top of this now. The issue is one of reporting.
> >
> > For the URI given, doc(uri) returns the following error in oxygen
> > "Failed to load document" doc-available(uri) returns false
> when using
> > SaxonSA.
> >
> > Neither error message provides any indication that these
> failures are
> > the product of validation errors. The file is, in fact,
> available, a
> > validation error prevents the file being loaded.
> >
> > This is why I get different results from SaxonB and SaxonSA.
> >
> > I'm not sure what the XPATH/XSLT standard requires here. Is doc-
> > available meant to return "true" only if the document is
> available AND
> > valid according to the currently specified schema? I'd
> guess so in a
> > schema aware environment but the simple two words "validation error"
> > in the error report would have saved me a good deal of time.
> >
> > With respect,
> > Steven
> >
> > --
> > Dr. Steven Ericsson-Zenith
> > Institute for Advanced Science & Engineering
> >
> >
> >
> >
> >
> >
> > On Sep 8, 2009, at 3:05 AM, George Cristian Bina wrote:
> >
> >> Hi Steven,
> >>
> >> I also used the schema-aware version of Saxon-SA 9.1.0.7
> and Saxon-EE
> >> 9.2. Maybe you can post the exact output you get when you run the
> >> samples I posted with Saxon SA?
> >>
> >> Best Regards,
> >> George
> >> --
> >> George Cristian Bina
> >> <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
> >>
> >>
> >> Steven Ericsson-Zenith wrote:
> >>> My note is with respect to the Schema Aware version of Saxon and
> >>> this code does not run immediately against that parser. I get the
> >>> same result you do with SaxonB.
> >>>
> >>> Steven
> >>>
> >>> On Sep 8, 2009, at 2:10 AM, George Cristian Bina wrote:
> >>>
> >>>> Hi Steven,
> >>>>
> >>>> I was not able to reproduce the issue you describe. For
> example, I
> >>>> configured a connection to the eXist demo server with
> the following
> >>>> data
> >>>>
> >>>> Name: memeio
> >>>> XML DB URI: xmldb:exist://demo.exist-db.org:8098/exist/xmlrpc
> >>>> User: guest
> >>>> Password: guest
> >>>> Collection: /db
> >>>>
> >>>> We created there a similar structure as in your message and the
> >>>> following XSLT and XQuery work fine:
> >>>>
> >>>> <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet
> >>>> xmlns:xsl="";
> >>>> xmlns:xs="";
> >>>>
> >>>> <xsl:output
> >>>> <xsl:template
> >>>> <xsl:variable
> >>>>oxygen:/eXist$memeio/db/memeio/documents/iase.info/
> >>>> supplement.xml</xsl:variable>
> >>>> <result>
> >>>> <status>
> >>>> <xsl:value-of select="if (doc-available($file)) then
> >>>> 'File supplement.xml exists, and is XML'
> else 'File
> >>>> not found or is not in XML format'"/>
> >>>> </status>
> >>>> <content>
> >>>> <xsl:copy-of</xsl:copy-of>
> >>>> </content>
> >>>> </result>
> >>>> </xsl:template>
> >>>> </xsl:stylesheet>
> >>>>
> >>>>
> >>>>
> >>>> declare variable
> >>>> $file:="oxygen:/eXist$memeio/db/memeio/documents/iase.info/
> >>>> supplement.xml";
> >>>> <result>
> >>>> <status>{
> >>>> if (doc-available($file))
> >>>> then 'File supplement.xml exists, and is XML'
> >>>> else 'File not found or is not in XML format'
> >>>> }</status>
> >>>> <content>{
> >>>> doc($file)
> >>>> }</content>
> >>>> </result>
> >>>>
> >>>> giving as result
> >>>>
> >>>> <?xml version="1.0" encoding="UTF-8"?> <result> <status>File
> >>>> supplement.xml exists, and is XML</status> <content>
> >>>> <supplement>Supplement file content</supplement> </content>
> >>>> </result>
> >>>>
> >>>> Maybe you can try the same examples against a connection to the
> >>>> eXist demo server and see if you get different results.
> >>>> We tested both with oXygen 10.3 /Saxon 9.1.0.7 and with
> the current
> >>>> oXygen code (not yet released) with Saxon 9.2.
> >>>>
> >>>> Best Regards,
> >>>> George
> >>>> --
> >>>> George Cristian Bina
> >>>> <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
> >>>>
> >>>>
> >>>> Steven Ericsson-Zenith wrote:
> >>>>> Dear List/Mike,
> >>>>>
> >>>>> I am having a problem when using the following URI
> >>>>>
> >>>>>
> oxygen:/exist$memeio/db/memeio/documents/iase.info/supplement.xml
> >>>>>
> >>>>> in SaxonSA. The collection function has no problem with the
> >>>>> similar
> >>>>>
> >>>>>
> oxygen:/exist$memeio/db/memeio/documents/iase.info/catalog.xml
> >>>>>
> >>>>> but doc doc-available and document indicate a problem. doc and
> >>>>> document return no error, they process the URI without
> complaint.
> >>>>> doc-
> >>>>> available returns false.
> >>>>>
> >>>>> The processed file is at a similar URI. All schema imports and
> >>>>> namespace declarations handle such URIs without complaint.
> >>>>>
> >>>>> By way of confirming the URI I cut and paste from an
> xsl:message
> >>>>> the same URI into Open URI in oxygen and it opens the correct
> >>>>> file.
> >>>>>
> >>>>> I've been beating my head on this for a day or two
> worried that I
> >>>>> have made some obvious blunder - if I have, I can't see it.
> >>>>>
> >>>>> What am I missing? Obvious question = does doc-available handle
> >>>>> such URIs correctly?
> >>>>>
> >>>>> With respect,
> >>>>> Steven
> >
> >
> >
> ----------------------------------------------------------------------
> > -------- Let Crystal Reports handle the reporting - Free Crystal
> > Reports 2008 30-Day trial. Simplify your report design, integration
> > and deployment - and focus on what you do best, core application
> > coding. Discover what's new with Crystal Reports now.
> >
> > _______________________________________________
> > saxon-help mailing list archived at
> > saxon-help@...
> >
>
> --
> Dr. Steven Ericsson-Zenith
> Institute for Advanced Science & Engineering
>
>
>
>
>
>
>
>
>
> --------------------------------------------------------------
> ----------------
> Let Crystal Reports handle the reporting - Free Crystal
> Reports 2008 30-Day trial. Simplify your report design,
> integration and deployment - and focus on what you do best,
> core application coding. Discover what's new with Crystal
> Reports now.
> _______________________________________________
> saxon-help mailing list archived at
> saxon-help@...
>
View entire thread | http://sourceforge.net/p/saxon/mailman/message/23511864/ | CC-MAIN-2014-35 | refinedweb | 970 | 56.45 |
Matt Draisey <matt at draisey.ca> wrote: [snip] -1 . The only thing that possibly should be fixed is that modules should only be inserted into sys.modules after they have been imported completely and correctly. > This would be a big change in module import semantics, but should have > remarkably few consequences, as it really is an enforcement mechanism > for good style. How is it an enforcement for good style? If I can do exactly what I'm doing now, then it isn't an enforcement mechanism in any way. Regardless, the way to handle not allowing the rest of your program to muck with partially initialized modules is to not use the standard import machinery. There are various ways of emulating module loading, many of which can allow you to insert the module into sys.modules *after* the module was loaded completely correctly. I actually use one of these methods to handle the dynamic loading and reloading of Python macros in a source code editor, and none of the macros are available in sys.modules . > The copying from the temporary namespace into the > module object would be a good place to insert a hook function to filter > what objects are actually published to the module. You could by default > not copy any object indentified by a leading underscore. You can already do this with the following code: __gl = globals() for name in __gl.keys(): if name[:1] == '_' and len(name) > 1 and name.count('_') == 1: del __gl[name] del __gl - Josiah | https://mail.python.org/pipermail/python-ideas/2007-January/000064.html | CC-MAIN-2017-30 | refinedweb | 253 | 64.61 |
Enum is a user-defined datatype. It is a set of integral constants termed as enumerators.
Enum has a limitation. Two enum in a scope cannot have same enumerators. To remove this limitation, C++11 introduced Strongly Typed Enum. Strongly Typed Enum allows you to have enumerators which can be redundant from any other enum. In declaration, a keyword 'class' is added after enum to specify it is a strongly typed enum.
syntax: enum class user-definedDatatype { ....};
Strongly typed enum, provides flexibility at the cost that it has to be used with scope resolution. The surrounding gets corrupted because of redundant enumerators. Hence it is a compilation error to declare or use strongly typed enum without scope resolution. Attached snippet will make it clear
Snippet of the same code to copy and try:
using namespace std;
int main(){
enum class colors { red, blue, aquamarine, yellow };
enum class PrimaryColors { green, blue, red };
enum SecondaryColors { magenta, yellow, cyan };
enum trafficlights { red, /*yellow, */ green }; //yellow is redundant
SecondaryColors sc = yellow;
// colors r = red;
colors r = colors::red;
}
Discussion (0) | https://practicaldev-herokuapp-com.global.ssl.fastly.net/jumana/strongly-typed-enum-1khh | CC-MAIN-2021-31 | refinedweb | 176 | 56.96 |
On Thursday 05 January 2006 10:54, Bjorn Helgaas wrote:> On Thursday 05 January 2006 10:37, Matt Domsch wrote:> > This system (Dell PowerEdge 7250, very very similar to an Intel> > 4-way Itanium2 server) doesn't have an SPMI table, but it does have> > the IPMI information in the SMBIOS table.> > But the IPMI device *should* be described in the ACPI namespace, so> using acpi_bus_register_driver() should be sufficient.You mentioned on IRC that /sys/firmware/acpi/namespace didn'tcontain anything that looked like an IPMI device. Try dumping theactual DSDT and looking there -- I'm not sure everything makes itinto /sys/firmware/acpi/...Use the latest "pmtools" from here: "iasl" to disassemble it.I did this on an Intel Tiger, and didn't see any "IPI" devices in thenamespace either. I think it's a firmware bug if the hardwareis there but not described in the namespace.So maybe you'd have to grub through SMBIOS to workaroundthe firmware defect.-To unsubscribe from this list: send the line "unsubscribe linux-kernel" inthe body of a message to majordomo@vger.kernel.orgMore majordomo info at read the FAQ at | http://lkml.org/lkml/2006/1/5/543 | CC-MAIN-2016-50 | refinedweb | 189 | 54.63 |
Opened 3 years ago
Closed 11 months ago
Last modified 11 months ago
#9520 closed bug (invalid)
Running an action twice uses much more memory than running it once
Description (last modified by )
EDIT: A detailed analysis of the problems discussed in this ticket can be found at . There is no ghc bug here, as such, except perhaps #8457 "-ffull-laziness does more harm than good". See also #12620 "Allow the user to prevent floating and CSE".
This started as a Haskell cafe discussion about conduit. This may be related to #7206, but I can't be certain. It's possible that GHC is not doing anything wrong here, but I can't see a way that the code in question is misbehaving to trigger this memory usage.
Consider the following code, which depends on conduit-1.1.7 and conduit-extra:
import Data.Conduit ( Sink, (=$), ($$), await ) import qualified Data.Conduit.Binary as CB import System.IO (withBinaryFile, IOMode (ReadMode)) main :: IO () main = do action "random.gz" --action "random.gz" action :: FilePath -> IO () action filePath = withBinaryFile filePath ReadMode $ \h -> do _ <- CB.sourceHandle h $$ CB.lines =$ sink2 1 return () sink2 :: (Monad m) => Int -> Sink a m Int sink2 state = do maybeToken <- await case maybeToken of Nothing -> return state Just _ -> sink2 $! state + 1
The code should open up the file "random.gz" (I simply
gziped about 10MB of data from /dev/urandom), break it into chunks at each newline character, and then count the number of lines. When I run it as-is, it uses 53KB of memory, which seems reasonable.
However, if I uncomment the second call to
action in
main, maximum residency shoots up to 45MB (this seems to be linear in the size of the input file. I additionally tried copying
random.gz into two files,
random1.gz and
random2.gz, and changed the two calls to
action to use different file names. It still resulted in large memory usage.
I'm going to continue working to make this a smaller reproducing test case, but I wanted to start with what I had so far. I'll also attach the core generated by both the low-memory and high-memory versions.
Attachments (3)
Change History (20)
Changed 3 years ago by
Changed 3 years ago by
High memory
comment:1 Changed 3 years ago by
Well I don't understand
conduit. But looking at
bad.core I see:
main3is called twice (in the RHS of
main1). This corresponds to the two calls of
action.
- So I wonder if there are any values shared between call calls of
main3. These will be top-level CAFs.
- Aha yes!
main5is shared. But it's fine: it is simply
Done ().
- Aha again! We see
main6 :: Data.Conduit.Internal.Pipe Data.ByteString.Internal.ByteString Data.ByteString.Internal.ByteString Data.Void.Void () IO Int main6 = main9 main8 (main7 `cast` ...)So if
main6generates a big data structure, it will be retained across both calls.
Back to you
comment:2 Changed 3 years ago by
OK, I've got a version of this that only relies on
base now:
import System.IO (withBinaryFile, IOMode (ReadMode), Handle, hIsEOF, hGetChar) main :: IO () main = do action --action action :: IO () action = do _ <- withBinaryFile "1mb" ReadMode $ \h -> connect (sourceHandle h) sinkCount return () data Conduit i o m r = Pure r | M (m (Conduit i o m r)) | Await (i -> Conduit i o m r) (Conduit i o m r) | Yield (Conduit i o m r) o sourceHandle :: Handle -> Conduit i Char IO () sourceHandle h = loop where loop = M $ do isEof <- hIsEOF h if isEof then return $ Pure () else do c <- hGetChar h return $ Yield loop c sinkCount :: Monad m => Conduit i o m Int sinkCount = loop 0 where loop cnt = Await (\_ -> loop $! cnt + 1) (Pure cnt) connect :: Monad m => Conduit a b m r' -> Conduit b c m r -> m r connect _ (Pure r) = return r connect (Yield left b) (Await right _) = connect left (right b) connect (Pure x) (Await _ right) = connect (Pure x) right connect (M mleft) right = mleft >>= flip connect right
Same behavior regarding
action. I'll attach a heap profile with the large memory usage.
Changed 3 years ago by
base-only heap profile
comment:3 Changed 3 years ago by
So if
main6generates a big data structure, it will be retained across both calls.
Well, that's sort of the idea: conduit is essentially a free monad, and it's evaluated by interpreting steps like "wait for next input" or "provide next value." What *should* be happening is that it creates a value indicating the next step, and that value is immediately consumed and garbage collected. Instead, for some reason it's maintaining this structure between multiple calls, even though the two data structures will not match (not that the
Handle used by each loop will be different).
Hopefully the base-only version of the code will demonstrate the issue more clearly.
comment:4 follow-up: 7 Changed 3 years ago by
Apologies if this is becoming repetitive, but here's a slightly simpler version demonstrating the same issue:
import System.IO data Sink i r = Sink (i -> Sink i r) r sinkCount :: Sink i Int sinkCount = loop 0 where loop cnt = Sink (\_ -> loop $! cnt + 1) cnt feed :: Handle -> Sink Char r -> IO r feed h = loop where loop (Sink f g) = do eof <- hIsEOF h if eof then return g else do c <- hGetChar h loop $! f c action :: IO () action = withBinaryFile "1mb" ReadMode $ \h -> do feed h sinkCount return () main :: IO () main = do action action
The following code, however, does *not* demonstrate the problem:
import System _) = loop (i - 1) (f 'A') action :: IO () action = do feed sinkCount return () main :: IO () main = do action action
comment:5 Changed 3 years ago by
comment:6 Changed 3 years ago by
As pointed out by Bryan Vicknair in the cafe thread, my first example in my previous comment does not always leak memory. In particular, I had to turn on optimizations (either
-O or
-O2) to get it to happen.
comment:7 Changed 3 years ago by
Replying to snoyberg:
Without looking at the core,
sinkCount has the potential to become a large shared data structure, if the
loop $! cnt + 1 part is floated out like so:
sinkCount :: Sink i Int sinkCount = loop 0 where loop cnt = let sink' = loop $! cnt + 1 in Sink (\_ -> sink') cnt
Then the run-time representation of
(\_ -> sink') is a closure that points to the next sink,
sink'. The first time
sinkCount is used it'll produce many sinks
(Sink (\_ -> sink') cnt) for increasing counts, each pointing to the next.
Ideally,
sinkCount and
feed should be fused, but that requires inlining parts of
sinkCount which given its recursive definition is tricky.
comment:8 Changed 3 years ago by
comment:9 Changed 12 months ago by
I have no answers here, just more questions. I ran into this problem again with a large project that uses conduit. My program suffered from a large memory leak, and in the
-hy profile the types were reported as
->Pipe and
Sink; moreover, the
-hc profile told me memory was being retained by a CAF. All of this pointed to the exact problem discussed in this ticket, and indeed adding
{-# OPTIONS_GHC -fno-full-laziness #-}
to the top of my module got rid of the problem. However, I can't say I fully understand what is going on. Experimenting with @snoyberg 's examples, above, I noticed that the memory behaviour of these modules interacts in odd ways with profiling options, which doesn't make this any easier! For @snoyberg's first example ():
| No profiling | -prof | -prof -fprof-auto ----+--------------+---------+------------------ -O0 | OK | OK | OK -O1 | OK | OK | LEAK(1) -O2 | OK | OK | LEAK(1)
where OK means "runs in constant space" and LEAK(1) indicates a memory leak consisting of
Int,
->Sink and
Sink, according to
+RTS -hy. In other words, this has a memory leak only when both optimization and
-fprof-auto are specified (
-fprof by itself is not enough).
Bizarrely, for the second example the behaviour is reversed (perhaps this is why Michael concluded that this example "however, does not demonstrate the problem"?):
| No profiling | -prof | -prof -fprof-auto ----+--------------+---------+------------------ -O0 | OK | OK | OK -O1 | LEAK | LEAK(1) | OK -O2 | LEAK | LEAK(1) | OK
Unlike for the first example, here we also get a LEAK without any profiling enabled (as indicated by a very high maximum residency reported by
+RTS -s).
I added a third example:
foreign import ccall "doNothing" doNothing :: _) = doNothing >> loop (i - 1) (f 'A') action :: IO () action = do feed sinkCount return () main :: IO () main = do action action
This differs from @snoyberg 's second example only in the additional call to
doNothing in
feed.loop;
doNothing is defined in an external
.c file:
void doNothing() {}
(I used an externally defined C function because I wanted something that the optimizer couldn't get rid of but without getting all kinds of crud about
Handles etc in the core/STG output, which is what would happen with a print statement, say.) I have no idea why, but this program's memory behaviour is quite different from version 2:
| No profiling | -prof | -prof -fprof-auto ----+--------------+---------+------------------ -O0 | LEAK | LEAK(2) | LEAK(2) -O1 | LEAK | LEAK(1) | LEAK(1) -O2 | LEAK | LEAK(1) | LEAK(1)
Now this program leaks no matter what we do; although LEAK(2) reported here, according to
RTS -hy, consists of different type (a single type, in fact:
PAP).
Getting to the bottom of this would require more time than I currently have; I guess for me the take-away currently is: full laziness is dangerous when using free monads such as conduit.
comment:10 Changed 12 months ago by
As Andres points out, my version 3 is not particularly enlightening; without any optimization, the loop in
feed is not tail recursive (this relies on unfolding of
>>); with optimization, we are bitten by the full laziness problem again. Bit of a red herring. (I had been trying to simulate the
hIsEOF in the original example.)
So I guess the only take away from my experimentation is: CAFs/full laziness and profiling modes interact in ways that make memory behaviour very unpredictable. Proceed with caution.
comment:11 Changed 11 months ago by
comment:12 Changed 11 months ago by
comment:13 Changed 11 months ago by
Ok, I believe there is no ghc bug here, although admittedly these issues are incredibly subtle. The memory leak comes from the full laziness optimization, as @int-e points out. The interaction with -fprof-auto that I observed comes from interaction of cost centres with the state hack. And the difference between Michael's two examples turns out to be unimportant; if you split example one into two separate modules so that the optimizer gets less change to optimize the heck out of it, the memory behaviour of both examples is identical.
I've written a long blog post that explores these issues in great detail; will publish soon.
comment:14 Changed 11 months ago by
Edsko: when you've written the post, do link it from this ticket so that people following the trail can find it. (Both as a comment and in the main Description, I suggest.)
Thanks
Simon
comment:15 Changed 11 months ago by
Sure. Article is now published at . It discusses all the issues mentioned in this ticket (including, as a bonus why prof-auto has the effect it has :). As requested will also add a link in the ticket description.
comment:16 Changed 11 months ago by
comment:17 Changed 11 months ago by
Terrific. I've added it to the Haskell Performance Resource
Simon
Low memory | https://ghc.haskell.org/trac/ghc/ticket/9520 | CC-MAIN-2017-34 | refinedweb | 1,951 | 67.08 |
Red Hat Bugzilla – Bug 68602
import gives bad results if X session being hit isn't current VT
Last modified: 2008-05-01 11:38:02 EDT
Description of Problem:
see bug #68601 - basically attempting to import -window root on a fresh X gives
weird results
Version-Release number of selected component (if applicable):
ImageMagick-5.4.3.11-1
How Reproducible:
100%
Steps to Reproduce:
1. X :2 (or whatever's not taken)
2. import -display :2 -window root /tmp/sshot.png
3. kview /tmp/sshot.png (or whatever viewer)
Actual Results:
bizarre - i'll attach my sshot attempt results, although bug 68601 has it too
Expected Results:
an sshot that shows the black X cursor, gray background, etc.
Additional Information:
I'd guess it's because X hasn't really displayed anything yet, so what get
sshot'd it just the pattern that X inititialized the double-buffering location
(not in video ram I'd imagine) to - not sure though
Created attachment 64826 [details]
sshot attempt of a fresh X
actually, it looks like it's not just limited to that case - I just tried to
sshot KDE starting up just after I logged in to kdm and the results are just as
bad - attempted sshot to come
Created attachment 64984 [details]
attempted shot of kde starting up
ok, playing around some more, what looks to be the problem is that if the import
runs when the X server being import'd isn't the currently selected vt, then you
get the garbage sshot's. Since import does the same in both cases, I'm more
likely to believe this is XF86's issue to deal with, so I'll change the assignment.
Mike - lemme know what I can do to debug this further
changing summary to better reflect the bug
Created attachment 65144 [details]
sshot of :0 when it wasn't the currently selected vt
Created attachment 65267 [details]
XFree86.0.log - hopefully helpful if this is specific to the driver
Multiple concurrant X servers do not simultaneously "share" the video
hardware. They use it one at a time. When you VTswitch out of one X
server, it completely restores the video card to it's state prior
to entering X, and switching to the other X server restores the video
state that that X server set up.
I'm not exactly sure I'd call this a bug. However if it is in fact
a bug, there isn't anything I/we can do about it, as I have no Savage
video hardware or documentation, so any fixes will have to come
from the upstream XFree86 Savage video driver maintainer. I recommend
discussing this on xpert@xfree86.org list to get a concensus of the
issue first, then contact Tim Roberts if it turns out to be considered
a bug.
Feel free to update this report with your findings, and if a patch or
fix results, I'll try to include it if possible. | https://bugzilla.redhat.com/show_bug.cgi?id=68602 | CC-MAIN-2017-13 | refinedweb | 498 | 50.91 |
Python Anonymous Function
We came so far in this tutorial series and reaching the end. This is the 19th part of the series Python. In this am gonna talk about Python Anonymous Function in details. In addition to that, I’ll also give some useful explanations to give you a clear cut view. But, before going any further, I recommend you guys, kindly go through the previous chapter. It will help you in grasping the things more easily. Anonymous Function
An anonymous function is a function which doesn’t require any name or we can say that it can be defined without using a def keyword, unlike normal function creation in the python.
In python anonymous function is defined using ‘Lambda’ keyword, that’s why it is also called a Lambda function.
Example:
find_val = lambda x : x*x+2 print (find_val(2))
Output:
6 27 >>>
Why Anonymous Function ??
Now, there might be a question blinking in your mind, what is the real use of lambda / anonymous function in Python, as we have already general functions available (using def keyword). Actually in python we do use anonymous function when we require a nameless for a short span of time.
Anonymous functions are actually quite useful. Python supports a style of programming called functional programming where you can pass functions to other functions to do some really cool stuff.
The above argument may be sound unfamiliar, let me explain in short.
“We do use anonymous function as an argument to a higher order function.”
Let’s take a close look at some example for more better understanding:
Example:
A simple program of sorting out even number from a list, using the traditional function: defining function name by using def keyword. Take a look
def myfunc(x): return (x % 2 == 0) even_num = list(filter(myfunc, [1, 2, 3, 4, 5, 6, 7, 8, 9])) print (even_num)
Output:
[2, 4, 6, 8] >>>
Explanation:
As you can observe it’s filtering the digits as per our function and respective operation. But we didn’t use anything specific. Now let’s achieve the same functionality using the anonymous method in python using lambda keyword. Take a look..
Example:
even_num = list(filter(lambda x: x % 2 == 0, [1, 2, 3, 4, 5, 6, 7, 8, 9])) print (even_num)
Output:
[2, 4, 6, 8] >>>
Explanation:
This method will also produce the same result.
Motive
The motive behind explaining the Python Anonymous Function is here to give you an insight. Insight about how easily you can achieve the same functionality using some different approach. Undoubtedly, the code will be better from time and space complexity as well.
Pin Points
- An anonymous function can not be directly call to the print, because unlike normal function lambda requires expression.
- It can take any number of the arguments but returns only one value in form of expression.
- Anonymous functions have their own local namespace.
- Anonymous functions can’t access variables other than those in their functioning parenthesis.
Never seen anything before, on Py anonymous function. You must have pulled your brain for that. | http://www.letustweak.com/tutorials/python-anonymous-function/ | CC-MAIN-2019-13 | refinedweb | 511 | 63.19 |
Should Languages be Multi-Lingual?
(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)
Arek Stryjski replied on Wed, 2009/10/21 - 4:26am
I don't think translating code has any advantages.
There is also question in which language we should learn programming languages.
Maybe to some people surprise, I'm not able to read Polish (my mother tongue) books about Java. When I started only English books where available, and when thinking and speaking about programming I just use English words even when talking in Polish.
Most programmers adopted this way to communicate. However some academics insist to not use this jargon, but pure Polish. In my opinion this makes they books less understandable for average developer.
To me the only open point in this discussion will be about language of specification and documentation.
Once I was in the project in Poland, with 100% Polish team, and for a Polish customer, and we used English for everything. There where some advantages for our employer in this case, but I also believe there where many disadvantages for a team.
In the end I think English is "lingua franca" of IT and it should stay this way.
To be a medical doctor you need to learn Latin, to be programmer you need to learn English. I don't have a problem with it.
Fab Mars replied on Wed, 2009/10/21 - 6:05am
I like this topic very much cause it's raised in any project with a non-anglo-saxon customer. And my return on experience on it is tha, most of the time, money matters drive you straight to english.
For the fun of it, I saw tricky situations with French a few times in past projects: Imagine nice things like method names with accents éèêàùô. Imagine english code with frequent french variable names and comments in arabic above. Sometimes a mix of all of this. Needless to say this happens in projects where the coding rules are not well clarified and where there's no serious code review. I saw that kind of things until 2005, and then less and less.
Indeed, in nowadays' globalization of the developments, the odds are that people who develop use a different language (and even alphabet) than the people who specify, which is different from the language (and alphabet) of the customer. You know like me that IT companies will commit to conduct developments in cheaper countries in order to get a lower bid price...or increase their margin. In that case it's very hard ot opt for something else than a 100% english usage, possibly using a glossary matching english business terms with the native language's one. We did that, it works but you have to review the code or good habits will be quickly lost :)
Needless to say that if a customer wants code and/or comments written in French, it's ok for me - the customer is always right - but he must be ready to have all his developments taking place in France, Belgium, Luxemburg, Québec or North Africa, and pay more than if the dev team was in India.
In any case, clear coding conventions must be written and enforced at all times.
I wouldn't advise a DSL in a specific language because of the overhead, and because I can bet my ass that, one day or another, a foreigner will have to have a look at it or support it.
The other way around, how about having language syntax using your own language? We've seen the VisualBasic example, thank you.
The flexibility offered by loke, lisp, etc, is really interesting but, in my area at least, customers want "a full blown enterprise language well established on the market, with no risk of having to pay for experts later like it's the case with Cobol now"...money concerns, again. So, 99% of mainstream projects developments will be in Java, .net, C(++) or PHP, Javascript, hence no chance of taking advantage of other languages' poossibilities.
Overall, IMO, in the Enterprise area, money concerns drive developments to 100% english and there's few you can to to curb it (provided you really want to). If you're doing a studies project, a homemade development or if your company insources all with its self employed team, you're welcome do what you want :)
Mike P(Okidoky) replied on Wed, 2009/10/21 - 11:25am
Myself, I'm from Dutch background, and learned programming when the Dutch weren't big yet on translating everything to Dutch. Also, TV was (is) generally subtitled and unlike, say, the Germans, I got used to English sounds that way. I've lived in Canada for quite a while, and I have had a particularly easy time working in English.
But what about having to work with people that are not comfortable with English. Like many Chinese?
How about using a small translation tool that is able to pick up translation definitions from the source files.
Like so:
public class Tree extends JTree /* Tree = nl:Boom ge:Baum */
{
private int name; /* name = nl:naam ge:nahm (?) */
}
etc. A tool could find these translation definitions and change the source code so the other guy can read it. It could be an Eclipse/Netbeans plugin that could do this on the fly. When checking the code back in (CVS, Git, whatever), it could automatically translate back to English.
This way, each person can comfortably work in their own language. New names that are added by people that don't know how to translate it could be added as:
private int #$@*(%$; /* #$@*(%$ = ? */
Which allows the translation tool to list words that aren't translated yet, which one of the team members that knows multiple languages can then help translate.
Danny Lee replied on Thu, 2009/10/22 - 8:34am
It's OK to produce multilingual DSLs for customisers and other non developers.
But multilingual programming language is a total overkill. If you want to lear a programming language you may be able to remember couple dozens keywords in English. | http://java.dzone.com/articles/should-languages-be-multi | CC-MAIN-2014-23 | refinedweb | 1,027 | 69.21 |
OK, suppose the following happens:
- Front-line helpdesk forwards (rather than bounces) a query into RT.
- The ticket appears with the helpdesk as requestor.
- We delete the helpdesk and add the email address of the end user as
requestor.
This email address isn’t an RT user at present, so RT tries to look
it up to change the requestor ID, and fails. Requestor ID is still
the helpdesk’s ID.
- We send correspondence, which correctly goes to the end user by email.
- End user replies.
Now what happens? End user doesn’t actually have a “user” entry in the
RT database, so when he replies, RT creates one for him. RT then
checks to see if this new user is the same as the requestor of the
ticket - which obviously it isn’t, because we’ve established in (3)
that the ID is still the helpdesk’s ID. (Trust me, we’ve seen this
happen here.) So the end user ends up having his mail bounced and
being told he’s not actually the requestor and doesn’t have permission
to correspond on the ticket.
Moral of the story? Requestors must have valid user IDs. This patch
makes it so.
— /home/simon/rt-2-0-6/lib/RT/Watcher.pm Tue Apr 3 07:31:14 2001
+++ RT/Watcher.pm Wed Oct 17 17:29:20 2001
@@ -78,8 +78,25 @@
}
}
- if ($args{‘Type’} eq “Requestor” and $args{‘Owner’} == 0) {
# Requestors *MUST* have an ID.
my $NewUser = RT::User->new($RT::SystemUser);
my ($Val, $Message) =
$NewUser->Create(Name => ($Username || $Address),
RealName => "$Name",
Password => undef,
Privileged => 0,
);
return (0, "Could not create watcher for requestor")
unless $Val;
if ($NewUser->id) {
$args{'Owner'} = $NewUser->id;
delete $args{'Email'};
}
- }
#Make sure we’ve got a valid type
#TODO — move this to ValidateType
return (0, “Invalid Type”)
Simon Cozens
Unix Systems Programmer
Oxford University Computer Services | https://forum.bestpractical.com/t/requestors-must-have-an-id/6483 | CC-MAIN-2020-24 | refinedweb | 313 | 72.97 |
Language INtegrated Queries are SQL-like C# queries that can be used to manipulate collections of objects.
In this article, I will show some cases of usage that show how LINQ can be used to query collections of objects.
The goal of this article is to be a beginners guide for LINQ, and a reference/reminder for others.
When people hear about LINQ, they in most cases think about something like
the Entity Framework, i.e., the possibility to write queries directly
in C# code that will be directly translated to SQL statements and executed against the database. It is important to know that this is not LINQ.
LINQ is a set of C# functions, classes, and operators that enable developers to execute queries against
a collections of objects.
True LINQ queries are executed against collections.
There are a lot of extensions of LINQ that translate queries to SQL, XML/XPath, REST, etc. In this article, I will talk about basic LINQ to collection queries.
There are two forms of LINQ operations - queries and functions. You can see more details about them in the following sections.
In the LINQ package is added a set of predefined operators (queries) that enable developers to create SQL-like queries on
a collection of objects.
These queries return new collections of data according to the query conditions. Queries are used in
the following form:
from <<element>> in <<collection>>
where <<expression>>
select <<expression>>
As a result of the query, a generic collection (IEnumerable<T>) is returned. Type <T> in the generic collection
is determined using the type of expression in the select <<expression>> part of
the query. An example of a LINQ query that returns
book titles for books with prices less than 500 is shown in the following listing:
IEnumerable<T>
<T>
<<expression>>
from book in myBooks
where book.Price < 500
select book.Title
This query goes through a collection of books myBooks that takes book entities which have a price property less than 500,
and for each title, returns the title. The result of the query is an object IEnumerable<String> because String is a type
of return expression in the select query (the assumption is that the
Title property of a book is string).
myBooks
IEnumerable<String>
String
Title
string
LINQ adds a set of useful function that can be applied to collections. Functions are added as new methods of collection objects and can be used in
the following form:
All LINQ queries are executed on the collections of type IEnumerable<T> or
IQueryable<T>, and as results are returned as new
collections (IEnumerable<T>), objects, or simple types. Examples of LINQ queries or functions that return collections are:
IQueryable<T>
IEnumerable<T> myBooks = allBooks.Except(otherBooks);
IEnumerable<string> titles = myBooks.Where(book=>book.Price<500)
.Select(book=>book.Title);
int count = titles.Count();
First of these three functions creates a new collection where are placed all books expect the ones that are in the otherBooks collection.
The second function takes all books with prices less than 500, and returns a list of their titles. The
third function finds a number of titles in the titles collection.
This code shows the usage of each of the three LINQ functions shown above.
otherBooks
titles
Note that there is a dual form of the LINQ queries and functions. For most of the queries you can write equivalent function form. Example is shown in the following code:
from book in myBooks
where book.Price < 500
select book.Title
myBooks
.Where(book=>book.Price<500)
.Select(book=>book.Title);
In the following sections can be found more examples about LINQ to collections.
As explained above, LINQ queries and functions return either classes or collections of classes. In most cases, you will use existing domain classes (Book, Author,
Publisher, etc.) in the return types of queries. However, in some cases you might want to return custom classes that do not exist in your class model.
As an example, you might want to return only the ISBN and title of the book, and therefore you do not want to return
an entire Book object with all properties
that you do not need at all. A similar problem will be if you want to return fields from different classes (e.g., if you want to return
the title of the book and name of publisher).
Book
In this case, you do not need to define new classes that contain only fields you want to use as return values. LINQ enables you to return so called
"anonymous classes" - dynamically created classes that do not need to be explicitly defined in your class model.
An example of such a kind of query is shown in the following example:
var items = from b in books
select new { Title: b.Title,
ISBN: b.ISBN
};
The variable items is a collection of dynamically created classes where each object has Title and ISBN properties. This class is not explicitly defined in your
class model - it is created dynamically for this query. If you try to find the type of variable items, you will probably see something like IEnumerable<a'> -
the .NET Framework
gives some dynamic name to the class (e.g., a'). This way you can use temporary classes just for the results of queries without
the need to define them in the code.
items
ISBN
IEnumerable<a'>
Many people think that this is a bad practice because we have used objects
here without type. This is not true - the items variable does have a type, however
the type
is not defined in some file. However, you have everything you need from the typed object:
However, there is a way to use untyped objects in .NET. If you replace the keyword var with
the keyword dynamic,
the variable items will be truly untyped. An example is shown in the following listing:
var
dynamic
dynamic items = from b in books
select new { Title: b.Title,
ISBN: b.ISBN
};
In this case you have a true untyped object - there will be no compile-time check (properties will be validated at run-time only) and you will not have
any Intellisense support for dynamic objects.
Although var is better than dynamic (always use
var where it is possible), there are some cases where you will be forced
to use dynamic instead of var. As an example, if you want to return
the result of some LINQ query as a return value of a method you cannot
declare the return type of the method as var because the scope of
the anonymous class ends in the method body. In that case you will need to either define
an explicit
class or declare the return value as dynamic.
In this article I will use either explicit or anonymous classes.
While you are working with LINQ, you will find some "weird syntax" in the form x => y. If you are not familiar with this syntax, I will explain it shortly.
x => y
In each LINQ function you will need to define some condition that will be used to filter objects. The most natural way to do this is to pass some function
that will be evaluated, and if an object satisfies a condition defined in the function, it will be included in the result set of the LINQ function.
That kind of condition function will need to take an object and return a true/false value that will tell LINQ whether or not this object should be included
in the result set. An example of that kind of function that checks if the book
is cheap is shown in the following listing:
public bool IsCheapBook(Book b)
{
return (b.Price < 10);
}
If the book price is less than 10, it is cheap. Now when you have this condition, you can use it in the LINQ clause:
var condition = new Func<Book, bool>(IsBookCheap);
var cheapBooks = books.Where(condition);
In this code we have defined a "function pointer" to the function IsBookCheap in the form Func<Book, bool>,
and this function is passed to the LINQ query. LINQ will evaluate this function for each book object in the books collection and return
a book in the resulting
enumeration if it satisfies the condition defined in the function.
IsBookCheap
Func<Book, bool>
This is not a common practice because conditions are more dynamic and it is unlikely that you can create a set of precompiled functions somewhere in the code,
and they will be used by all LINQ queries. Usually we need one expression per LINQ query so it is better to dynamically generate and pass
a condition to LINQ. Fortunately C# allows us to do this using delegates:
var cheapBooks = books.Where(delegate(Book b){ return b.Price < 10; } );
In this example, I have dynamically created Function<Book, bool>, and put it directly in the
Where( ) condition.
The result is the same as in the previous example but you do not need to define
a separate function for this.
Function<Book, bool>
Where( )
If you think that this is too much typing for a simple inline function, there is a shorter syntax - lambda expressions. First you can see that we
don't need the delegate word (the compiler should know that we need to pass
a delegate as an argument). Also, why do we need to define the type of the argument
(Book b)? As we are applying this function to the collection of books, we know that
b is a Book - therefore we can remove this part too.
Also, why should we type return - an expression that defines the return condition will be enough. The only thing we would need to have is
a separator that will
be placed between the argument and the expression that will be returned - in C#,
we use => symbol.
delegate
Book b
b
return
=>
When we remove all the unnecessary stuff and put a separator =>, we are getting
a lambda expression syntax in the form argument => expression.
An original delegate and equivalent lambda expression replacement is shown in the following example:
argument => expression
Funct<Book, bool> delegateFunction = delegate(Book b){ return b.Price < 10; } ;
Funct<Book, bool> lambdaExpression = b => b.Price< 10 ;
As you can see, a lambda expression is just a minimized syntax for inline functions. Note that
we can use lambda expressions for any kind of function (not only functions that
return bool values). As an example, you can define a lambda expression that takes
a book and author, and returns a book title in the format book
"title (author name)". An example of that kind of lambda expression is shown in the following listing:
bool
Func<Book, Author, string> format = (book, author) => book.Title + "(" + author.Name + ")";
This function will take two arguments (Book and Author), and return
a string as a result (the last type in the Func<> object is always
the return type).
In the lambda expression are defined two arguments in the brackets and the string expression that will be returned.
Author
Func<>
Lambda expressions are widely used in LINQ, so you should get used to them.
In the examples, we will use a data structure that represents information about books, their authors, and publishers.
The class diagram for that kind of data structure is shown on the figure below:
Each book can have several authors and one publisher. The fields associated to entities are shown on
the diagram. Book has information about ISBN, price, number of pages,
publication date, and title. Also, it has a reference to a publisher, and a reference to
a set of authors. Author has a first name and last name without reference back
to a book, and publisher has just a name without reference to books he published.
There will be the assumption that a collections of books, publishers, and authors are placed in
the SampleData.Books, SampleData.Publishers, and SampleData.Authors fields.
In this section I will show some examples of basic queries/functions that can be used. If you are
a beginner this should be a good starting point for you.
The following example shows the basic usage of LINQ. In order to use a LINQ to
Entities query, you will need to have a collection (e.g., array of books)
that will be queried. In this basic example, you need to specify what collection will be queried ("from <<element>>
in <<collection>>" part) and what data will be selected in
the query ("select <<expression>>" part).
In the example below, the query is executed against a books array, book entities are selected, and returned as result of queries.
The result of the query
is IEnumerable<Book> because the type of the expression in
the "'select << expression>>" part is the class
Book.
IEnumerable<Book>
Book[] books = SampleData.Books;
IEnumerable<Book> bookCollection = from b in books
select b;
foreach (Book book in bookCollection )
Console.WriteLine("Book - {0}", book.Title);
As you might have noticed, this query does nothing useful - it just selects all books from the book collection and puts them in the enumeration. However, it shows
the basic usage of the LINQ queries. In the following examples you can find more useful queries.
Using LINQ, developers can transform a collection and create new collections where elements contain just some fields.
The following code shows how you can create
a collection of book titles extracted from a collection of books.
Book[] books = SampleData.Books;
IEnumerable<string> titles = from b in books
select b.Title;
foreach (string t in titles)
Console.WriteLine("Book title - {0}", t);
As a result of this query, IEnumerable<string> is created because
the type of expression in the select part is string.
An equivalent example written as a select function and lambda expression is shown in the following code:
IEnumerable<string>
Book[] books = SampleData.Books;
IEnumerable<string> titles = books.Select(b=>b.Title);
foreach (string t in titles)
Console.WriteLine("Book title - {0}", t);
Any type can be used as a result collection type. In the following example,
an enumeration of anonymous classes is returned, where each element in the enumeration
has references to the book and the first author of the book:
var bookAuthorCollection = from b in books
select new { Book: b,
Author: b.Authors[0]
};
foreach (var x in bookAuthorCollection)
Console.WriteLine("Book title - {0}, First author {1}",
x.Book.Title, x.Author.FirstName);
This type of queries are useful when you need to dynamically create a new kind of collection.
Imagine that you want to return a collection of authors for a set of books. Using
the Select method, this query would look like the one in the following example:
Book[] books = SampleData.Books;
IEnumerable< List<Author> > authors = books.Select(b=>b.Authors);
foreach (List<Author> bookAuthors in authors)
bookAuthors.ForEach(author=>Console.WriteLine("Book author {0}", author.Name);
In this example, from the book collection are taken a list of authors for each book. When you use
the Select method, it will return an element in the resulting
enumeration and each element will have the type List<Author>, because that is a type of property that is returned in
the Select method. As a result,
you will need to iterate twice over the collection to display all authors - once to iterate through the enumeration, and then for each list in
the enumeration, you
will need to iterate again to access each individual author.
List<Author>
However, in some cases, this is not what you want. You might want to have a single flattened list of authors and not
a two level list. In that case, you will
need to use SelectMany instead of the Select method as shown in the following example:
SelectMany
Book[] books = SampleData.Books;
IEnumerable<Author> authors = books.SelectMany(b=>b.Authors);
foreach (Author authors in authors)
Console.WriteLine("Book author {0}", author.Name);
The SelectMany method merges all collections returned in the lambda expression into the single flattened list. This way you can easily manipulate
the elements of a collection.
Note that in the first example, I have used the ForEach method when I have iterated through the list of authors in order to display them.
The ForEach method is not
part of LINQ because it is a regular extension method added to the list class. However it is
a very useful alternative for compact inline loops (that is probably the reason
why many people think that it is part of LINQ). As the ForEach method,
it is not part of LINQ, you cannot use it on an enumeration as a regular LINQ method
because it is defined as an extension for List<T> and not
Enumerable<T> - if you like this method, you will need to convert your enumerable to
a list in order to use it.
ForEach
List<T>
Enumerable<T>
Using LINQ, developers can sort entities within a collection. The following code shows how you can take
a collection of books, order elements by book publisher name and
then by title, and select books in an ordered collection. As a result of the query, you will get
an IEnumerable<Book> collection sorted by book publishers and titles.
Book[] books = SampleData.Books;
IEnumerable<Book> booksByTitle = from b in books
orderby b.Publisher.Name descending, b.Title
select b;
foreach (Book book in booksByTitle)
Console.WriteLine("Book - {0}\t-\tPublisher: {1} ",
book.Title, book.Publisher.Name );
Alternative code using functions is shown in the following example:
Book[] books = SampleData.Books;
IEnumerable<Book> booksByTitle = books.OrderByDescending(book=>book.Publisher.Name)
.ThenBy(book=>book.Title);
foreach (Book book in booksByTitle)
Console.WriteLine("Book - {0}\t-\tPublisher: {1} ",
book.Title, book.Publisher.Name );
This type of queries is useful if you have complex structures where you will need to order
an entity using the property of a related entity (in this example,
books are ordered by publisher name field which is not placed in the book class at all).
Using LINQ, developers can filter entities from a collection and create a new collection containing just entities that satisfy
a certain condition.
The following example creates a collection of books containing the word "our" in the title with price less than 500. From
the array of books are selected
records whose title contains the word "our", price is compared with 500, and these books are selected and returned as members of
a new collection.
In ''where <<expression>>'' can be used a valid C#
boolean expression that uses the fields in a collection, constants,
and variables in a scope (i.e., price). The type of the returned collection is IEnumerable<Book> because in
the ''select <<expression>>''
part is the selected type Book.
Book[] books = SampleData.Books;
int price = 500;
IEnumerable<Book> filteredBooks = from b in books
where b.Title.Contains("our") && b.Price < price
select b;
foreach (Book book in filteredBooks)
Console.WriteLine("Book - {0},\t Price {1}", book.Title, book.Price);
As an alternative, the .Where() function can be used as shown in the following example:
.Where()
Book[] books = SampleData.Books;
int price = 500;
IEnumerable<Book> filteredBooks = books.Where(b=> (b.Title.Contains("our")
&& b.Price < price) );
foreach (Book book in filteredBooks)
Console.WriteLine("Book - {0},\t Price {1}", book.Title, book.Price);
You can use local variables in LINQ queries in order to improve the readability of your queries.
Local variables are created using the let <<localname>> = <<expression>> syntax inside the LINQ query.
Once defined, local variables can be used in any part in the LINQ query (e.g.,
where or select clause). The following example shows how
you can select a set of first authors in the books containing the word 'our' in
the title, using local variables.
let <<localname>> = <<expression>>
where
IEnumerable<Author> firstAuthors = from b in books
let title = b.Title
let authors = b.Authors
where title.Contains("our")
select authors[0];
foreach (Author author in firstAuthors)
Console.WriteLine("Author - {0}, {1}",
author.LastName, author.FirstName);
In this example, variables Title and Authors reference
the title of the book and the list of authors. It might be easier to reference these items via variables instead of
a direct reference.
Authors
Using LINQ, you can modify existing collections, or collections created using other
LINQ queries. LINQ provides you a set of functions that can be applied to collections.
These functions can be grouped into the following types:
These functions are described in the following sections.
Set operators enable you to manipulate collections and use standard set operations like unions, intersects, etc. LINQ set operators are:
Assuming that the booksByTitle and filteredBooks collection are created in previous examples,
the following code finds all books in booksByTitle
that do not exist in filteredBooks, and reverses their order.
booksByTitle
filteredBooks
IEnumerable<Book> otherBooks = booksByTitle.Except(filteredBooks);
otherBooks = otherBooks.Reverse();
foreach (Book book in otherBooks)
Console.WriteLine("Other book - {0} ", book.Title);
In the following example, booksByTitle and filteredBooks are concatenated and
the number of elements and number of distinct elements is shown.
IEnumerable<Book> mergedBooks = booksByTitle.Concat(filteredBooks);
Console.WriteLine("Number of elements in merged collection is {0}", mergedBooks.Count());
Console.WriteLine("Number of distinct elements in merged collection is {0}", mergedBooks.Distinct().Count());
In this example is shown an example of client side paging using the Skip(int) and
Take(int) methods. Assuming that there are ten books per page,
the first three pages are skipped using Skip(30) (ten books per page placed on three pages), and all books that should be shown on
the fourth page are taken using Take(10). An example code is:
Skip(int)
Take(int)
Skip(30)
Take(10)
IEnumerable<Book> page4 = booksByTitle.Skip(30).Take(10);
foreach (Book book in page4)
Console.WriteLine("Fourth page - {0} ", book.Title);
There is also an interesting usage of the Skip/Take functions in the
SkipWhile/TakeWhile form:
Skip
Take
SkipWhile
TakeWhile
IEnumerable<Book> page1 = booksByTitle.OrderBy(book=>book.Price)
.SkipWhile(book=>book.Price<100)
.TakeWhile(book=>book.Price<200);
foreach (Book book in page1)
Console.WriteLine("Medium price books - {0} ", book.Title);
In this example, books are ordered by price, all books with price less than 100 are skipped, and all books with price less than 200 are returned.
This way all books with price between 100 and 200 are found.
There are several useful functions that can be applied when you need to extract
a particular element from a collection:
First
FirstOrDefault
ElementAt
The following example shows the usage of the FirstOrDefault and
ElementAt functions:
Book firstBook = books.FirstOrDefault(b=>b.Price>200);
Book thirdBook = books.Where(b=>b.Price>200).ElementAt(2);
Note that you can apply functions either on the collection, or on the result of some other LINQ function.
There are a few conversion functions that enable you to convert the type of one collection to another. Some of these functions are:
ToArray
ToList
ToDictionary
Dictionary
OfType
IEnumerable<T1>
T2
IEnumerable<T2>
The following example shows the usage of the ToArray and ToList functions:
Book[] arrBooks = books.ToArray();
List<Book> lstBook = books.ToList();
ToDictionary is an interesting method that enables you to quickly index
a list by some field. An example of such a kind of query is shown in the following listing:
Dictionary<string, Book> booksByISBN = books.ToDictionary(book => book.ISBN);
Dictionary<string, double> pricesByISBN = books.ToDictionary( book => book.ISBN,
book=>book.Price);
If you supply just one lambda expression, ToDictionary will use it as a key of new dictionary while
the elements will be the objects. You can also supply
lambda expressions for both key and value and create a custom dictionary. In the example above,
we create a dictionary of books indexed by the ISBN key, and a dictionary of prices indexed by ISBN.
In each collection, you can find a number of logical functions that can be used to quickly travel through
a collection and check for some condition.
As an example, some of the functions you can use are:
Any
All
An example of usage of functions is shown in the following example:
if(list.Any(book=>book.Price<500))
Console.WriteLine("At least one book is cheaper than 500$");
if(list.All(book=>book.Price<500))
Console.WriteLine("All books are cheaper than 500$");
In the example above, the All and Any functions will check whether the condition that price is less than 500 is satisfied for books in the list.
Aggregation functions enable you to perform aggregations on elements of a collection. Aggregation functions that can be used in LINQ are
Count, Sum, Min, Max, etc.
Count
Sum
Min
Max
The following example shows the simple usage of some aggregate functions applied to
an array of integers:
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
Console.WriteLine("Count of numbers greater than 5 is {0} ", numbers.Count( x=>x>5 ));
Console.WriteLine("Sum of even numbers is {0} ", numbers.Sum( x=>(x%2==0) ));
Console.WriteLine("Minimum odd number is {0} ", numbers.Min( x=>(x%2==1) ));
Console.WriteLine("Maximum is {0} ", numbers.Max());
Console.WriteLine("Average is {0} ", numbers.Average());
As you can see, you can use either standard aggregation functions, or you can preselect
a subset using a lambda condition.
This section shows how you can create advanced queries. These kinds of queries includes joining different collections and using group by operators.
LINQ enables you to use SQL-like joins on a collection of objects. Collections are joined
the same way as tables in SQL. The following example shows how you can join
three collections publishers, books, and authors, place some restriction conditions in
the where section, and print results of
the query:
var baCollection = from pub in SampleData.Publishers
from book in SampleData.Books
from auth in SampleData.Authors
where book.Publisher == pub
&& auth.FirstName.Substring(0, 3) == pub.Name.Substring(0, 3)
&& book.Price < 500
&& auth.LastName.StartsWith("G")
select new { Book = book, Author = auth};
foreach (var ba in baCollection)
{ Console.WriteLine("Book {0}\t Author {1} {2}",
ba.Book.Title,
ba.Author.FirstName,
ba.Author.LastName);
}
This query takes publishers, books, and authors; joins books and publishers via Publisher reference, joins authors and publications by
the first three letters of the name.
In addition results are filtered by books that have prices less than 500, and authors with name starting with letter "G". As you can see,
you can use any condition to join collection entities.
LINQ enables you to use thw ''<<collection>> join <<collection>> on <<expression>>'' operator
to join two collections on join condition. It is similar to the previous example but you can read queries easily.
The following example shows how you can join publishers with
their books using a Book.Publisher reference as a join condition.
Book.Publisher
var book_pub = from p in SampleData.Publishers
join b in SampleData.Books on p equals b.Publisher
into publishers_books
where p.Name.Contains("Press")
select new { Publisher = p, Books = publishers_books};
foreach (var bp in book_pub){
Console.WriteLine("Publisher - {0}", bp.Publisher.Name);
foreach (Book book in bp.Books)
Console.WriteLine("\t Book - {0}", book.Title);
}
A collection of books is attached to each publisher record as a publishers_books property. In the
where clause, you can filter publishers by a condition.
publishers_books
Note that if you are joining objects by references (in the example above, you can see that
the join condition is p equals b.Publisher) there is a possibility
that you might get an "Object reference not set to the instance objects" exception if
the referenced objects are not loaded. Make sure that you have loaded all related
objects before you start the query, make sure that you handled null values in
the query, or use join conditions by IDs instead of references where possible.
p equals b.Publisher
LINQ enables you to use group by functionality on a collection of objects.
The following example shows how you can group books by year when they are published.
As a result of the query is returned an enumeration of anonymous classes containing
a property (Year) that represents a key used in the grouping, and another property (Books)
representing a collection of books published in that year.
Year
Books
var booksByYear = from book in SampleData.Books
group book by book.PublicationDate.Year
into groupedByYear
orderby groupedByYear.Key descending
select new {
Value = groupedByYear.Key,
Books = groupedByYear
};
foreach (var year in booksByYear){
Console.WriteLine("Books in year - {0}", year.Value);
foreach (var b in year.Books)
Console.WriteLine("Book - {0}", b.Title);
}
Using LINQ and group by, you can simulate a "
select title, count(*) from
table
var raw = new[] { new { Title = "first", Stat = 20, Type = "view" },
new { Title = "first", Stat = 12, Type = "enquiry" },
new { Title = "first", Stat = 0, Type = "click" },
new { Title = "second", Stat = 31, Type = "view" },
new { Title = "second", Stat = 17, Type = "enquiry" },
new { Title = "third", Stat = 23, Type = "view" },
new { Title = "third", Stat = 14, Type = "click" }
};
var groupeddata = from data in raw
group data by data.Title
into grouped
select new { Title = grouped.Key,
Count = grouped.Count()
};
foreach (var data in groupeddata){
Console.WriteLine("Title = {0}\t Count={1}", data.Title, data.Count);
}
LINQ enables you to use nested queries. Once you select entities from a collection, you can use them as part of
an inner query that can be executed on the other collection.
As an example, you can see the class diagram above that has class Book
that has a reference to the class Publisher, but there is no reverse relationship. Using nested LINQ queries, you
can select all publishers in a collection and for each publisher entity, call other LINQ queries that find all books that have
a reference to a publisher. An example of such
a query is shown below:
Publisher
var publisherWithBooks = from publisher in SampleData.Publishers
select new { Publisher = publisher.Name,
Books = from book in SampleData.Books
where book.Publisher == publisher
select book
};
foreach (var publisher in publisherWithBooks){
Console.WriteLine("Publisher - {0}", publisher.Name);
foreach (Book book in publisher.Books)
Console.WriteLine("\t Title \t{0}", book.Title);
}
When a new instance is created in a query, for each publisher entity is taken
a collection of Books set in the LINQ query and shown on console.
Using local variables you can have a better format for the query as shown in
the following example:
var publisherWithBooks = from publisher in SampleData.Publishers
let publisherBooks = from book in SampleData.Books
where book.Publisher == publisher
select book
select new { Publisher = publisher.Name,
Books = publisherBooks
};
foreach (var publisher in publisherWithBooks){
Console.WriteLine("Publisher - {0}", publisher.Name);
foreach (Book book in publisher.Books)
Console.WriteLine("\t Title \t{0}", book.Title);
}
In this query, books for the current publisher are placed in the publisherBooks variable, and then is returned
an object containing the name of the publisher and his books.
publisherBooks
This way you can dynamically create new relationships between entities that do not exist in your original class model.
Usage of LINQ on collections of entities may significantly improve your code. Some common operations on collections like filtering, sorting, finding minimum or maximum,
can be done using a single function call or query. Also, a lot of LINQ features enable you to use collections in
a SQL-like manner enabling you to join collections, and group
them like in standard SQL. Without LINQ, for that kind functionality you might need to create several complex functions, but now with
the LINQ library, you can do it in a single statement.
If you have any suggestions for improving this article or some interesting usage of LINQ queries, let me know and I will add. | https://www.codeproject.com/Articles/286255/Using-LINQ-Queries?msg=4557557 | CC-MAIN-2020-16 | refinedweb | 5,232 | 56.15 |
A little video to explain pointer basics in C++ to your kids... If you for some weird reason want to do that...
I.
Using coding katas is a good way to learn and fine tune TDD/BDD skills. A common way to perform the code katas is in a coding dojo. But a coding dojo involves a lot of people and doing katas on your own might feel a little bit boring. At least I think doing katas alone is boring. So recently I tried out Project Euler. Project Euler is a site where you solve different more or less difficult problems and you solve them any way you like. I've started solving the problems using BDD style specs with the xUnit.net framework. Even though most problems are mathematical in nature I think it is a fun alternative to doing code katas on your own. And you get a chance to dust off a few of the mathematical skills from school that you thought you'd never need again.
If you have a Project Euler account and is logged in you can use this link to view my stats.
Many (agile) projects uses a burn down chart to track remaining time. It is a commonly used visualization "tool" for progress. But there are also teams that keep track of completed time for each task. Typically they do this in order to see how the completed time corresponds to the initial estimate. using this information the team hopes to improve their ability to estimate things correctly.
So even though the purpose is often the same, the reason is often one of two things. If the team is lucky it was the team that decided to track completed effort because the team believed this was the best way to improve the team's estimation skills. On the other hand I think a much more common scenario is that management want the team to track completed effort because they want to know how good the team is at estimating and management thinks that tracking completed effort will help the team improve estimation skills.
In the past I've had no problem when the team decides to track completed effort since it is a team decision. But when it is enforced by management all kinds of alarms are triggered in my head and I do my best to prevent it. I guess this is how many people see this and many other things. As long as it is a team decision to do something it is alright. The team will stop doing it if it turned out to be a bad idea.
So if you're working as an agile coach and the team comes up with the idea of tracking completed effort in order to gather data and improve their estimation skills, should you encourage them to do so? Up until recently I would have said yes every time. But now I've changed my mind since I recently was involved in a discussion regarding this and I was presented with an argument that made me change my mind completely. take a look at the following burn down chart.
The chart consists of an iteration with 20 working days. The team starts the iteration with the assumption it will complete 20 story points (or what ever you want to call them). So in essence they believe they will complete one story point per day. So if the team is making correct estimations they will complete just that and there is no need to track completed effort since the estimate is correct.
Now look at the green (over estimate) line. The team have over estimated the effort and completes 20 story points in just 14 days. This means their velocity is not 1 story point per day but rather 1,43 story points per day. So they have over estimated every thing by approximately 40%. Without having to look at each task we can see that the estimates should be reduced by 40% if we want to do 20 story points each day.
Looking at the red (under estimating) line we see that the team completed 14 story points in 20 days giving us a velocity of 0,7 story points per day. Adjusting the estimates means we have to add 40% to each existing estimate if the goal is to do 20 story points in each iteration.
When using story points you don't typically change the estimates - you change the velocity for the next iteration. But I think this example shows that tracking completed effort is not really needed if you want to improve estimation skills. Some estimations will always be higher and some lower. And looking at the totals there is no need to track completed effort since the total completed effort is a known value. It is the length of the iteration. Using this technique you'll probably have enough data to improve without adding the overhead of tracking completed effort or risking the team thinking tracking completed effort is just a way of tracking who does a good job and who doesn't.
So now for the advanced part of this dilemma. I still think there is one situation where tracking completed effort may be of value. First of all it must be a team decision. Second, it must be a team decision. And third, the purpose is to identify tasks that grow extremely much in order to evaluate the reason for such growth during the retrospect. The team might even be good at estimating on average, but they have a feeling (or just know) that some things are extremely over- and/or under estimated. And the team wants to make sure they identify these tasks in order to discuss them specifically during the retrospect. But the team must remember the purpose here. The completed effort does not need to be very accurate. Just accurate enough to identify the extremes. And in order to do that I don't think the team have to track effort on every task.
The..
When.
Since I'm not a fan of mocks I guess my prayers have been heard. Microsoft Research will soon release a stub framework. That's right. Stubs and not mocks! It is part of Pex that I have mentioned before. And you don't need to use Pex if you don't want. You can just use the stub framework by it self.
The new stub framework can currently be used to stub interfaces. It creates the stubs by generating code. At first this scared me since I feared it would not regenerate the stubs when the interface changed (which might happen quite common when creating the interface using BDD). But it works just fine and detects changes in the assembly and regenerates the stubs. Very convenient.
Another convenient thing is that it supplies default implementations for methods if I want. The default is to throw an StubNotImplementedException but I can change that and return default values (null, 0, empty string etc) if that is what I want. And the change can be made globally for all stubs created after the change or for a single stub object.
So how does this work? Consider the following interface:
public interface IMyInterface
{
int DoStuff();
}
I just tell the stub framework to generate stubs for the assembly containing the interface and it will generate a new namespace with the stubs. If IMyInterface is part of MyNamespace the stub framework will create a new namespace MyNamespace.Stubs with a class SMyInterface. Now we want to make a test. The test below doesn't really make since since it tests the stub instead of something using the stub, but I want to show the code that makes the stub work without the surrounding stuff so bare with me...
void TestStub()
{
MyNamespace.Stubs.SMyInterface o = new MyNamespace.Stubs.SMyInterface();
MyNamespace.IMyInterface i = o;
Assert.Equal(42, i.DoStuff());
}
Now the test will fail since the stub will throw an exception since the stub is not implemented. Let's use the default implementation:
void TestStub()
{
MyNamespace.Stubs.SMyInterface o = new MyNamespace.Stubs.SMyInterface();
o.DefaultStub = Microsoft.Stubs.DefaultStub<MyNamespace.Stubs.SMyInterface>.DefaultValue;
MyNamespace.IMyInterface i = o;
Assert.Equal(42, i.DoStuff());
}
Still a failure since the stub returns zero for DoStuff(). Let's stub that method.
void TestStub()
{
MyNamespace.Stubs.SMyInterface o = new MyNamespace.Stubs.SMyInterface();
o.DefaultStub = Microsoft.Stubs.DefaultStub<MyNamespace.Stubs.SMyInterface>.DefaultValue;
o.DoStuff = (stub) => { return 42; };
MyNamespace.IMyInterface i = o;
Assert.Equal(42, i.DoStuff());
}
Now the test passes! I think this new framework is an excellent addition to the developer's toolbox. And I think it is a better starting framework than all the mock frameworks out there. In the few cases that a mock framework is really needed (over a stub framework) you can easily extend your stub to verify behavior in the same way as a mock does. Currently the stub framework have a few limitations such as only being able stub interfaces. But I'll guess we'll have to wait and see what will be part of the release once it is available to the public (when writing this I've been using an internal release available to Microsoft staff only).
First. | http://blogs.msdn.com/b/cellfish/archive/2008/10.aspx?PageIndex=1 | CC-MAIN-2015-14 | refinedweb | 1,548 | 64.1 |
I'm getting some strange errors that I've worked through to this point.
I have an Ubuntu server setup with Apache + mod_wsgi + Django. When I'm SSH'd into the server, I can access the website fine from a browser on a different machine, and everything looks splendid. When I'm not SSH'd in, I get a 404 Not Found on my Browser, with this as the error in my Apache logs:
[Wed Apr 18 10:15:02 2012] [error] [client ..*.*] Target WSGI script not found or unable to stat: /home/zen/kiosk
[Wed Apr 18 10:15:02 2012] [error] [client ..*.*] Target WSGI script not found or unable to stat: /home/zen/kiosk
(The thing that bothers me the most about this error, is that the target WSGI script is not the full path I have listed in my apache config file)
Versions:
Apache Config:
Alias /static/ /home/zen/kiosk/static/
User zen
<Directory /home/zen/kiosk/static>
Order deny,allow
Allow from all
</Directory>
WSGIScriptAlias / /home/zen/kiosk/server/config/django.wsgi
#Alias / /home/zen/kiosk/server/config/django.wsgi
<Directory /home/zen/kiosk/server/config>
Order allow,deny
Allow from all
</Directory>
When Using just Alias instead of WSGIScriptAlias (as commented out in the Config file), I'm able to see the wsgi file if I'm SSH'd in, but get the same 404 I get up above with this as the error message:
[Wed Apr 18 11:10:01 2012] [error] [client ..*.*] File does not exist: /home/zen/kiosk
[Wed Apr 18 11:10:01 2012] [error] [client ..*.*] File does not exist: /home/zen/kiosk
WSGI Config (/home/zen/kiosk/server/config/django.wsgi)
import os, sys
sys.path.insert(0, '/home/zen/kiosk/server')
sys.path.insert(0, '/home/zen/kiosk')
os.environ['DJANGO_SETTINGS_MODULE'] = 'server.settings'
os.environ['PYTHON_EGG_CACHE'] = '/var/www/.python-eggs'
os.environ["CELERY_LOADER"] = "django"
import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()
sys.stdout = sys.stderr
Everything /home/zen/kiosk and under were chmoded to 755, but that didn't really seem to matter.
drwxr-xr-x 8 zen zen 4096 2012-04-16 16:13 /home/zen
zen@KioskServer:~$ ls -ld /home/zen/kiosk
drwxr-xr-x 8 zen zen 4096 2012-04-11 12:52 /home/zen/kiosk
zen@KioskServer:~$ ls -ld /home/zen/kiosk/server/
drwxr-xr-x 8 zen zen 4096 2012-04-16 15:05 /home/zen/kiosk/server/
zen@KioskServer:~$ ls -ld /home/zen/kiosk/server/config/
drwxr-xr-x 3 zen zen 4096 2012-04-03 22:05 /home/zen/kiosk/server/config/
zen@KioskServer:~$ ls -l /home/zen/kiosk/server/config/django.wsgi
-rwxr-xr-x 1 zen zen 504 2012-04-16 14:44 /home/zen/kiosk/server/config/django.wsgi
When I remove "User zen" from the Apache Config file, I get the following error instead of the Target WSGI script one, as long as I'm not SSH'd into the server.
[Wed Apr 18 10:29:02 2012] [error] [client ..*.*] (13)Permission denied: access to /login/ denied
[Wed Apr 18 10:29:02 2012] [error] [client ..*.*] (13)Permission denied: access to /login/ denied
Where my Browser has a 403 Forbidden error. This error also doesn't occur when I'm SSH'd in.
This feels like some Permissions error, or maybe some issue with some Path variables. Unfortunately, I'm kind of stuck at this point and I'm not sure what else to try.
Thanks
Edit: I saw on a different thread someone ask for this command (dpkg -l *apache* |grep -E '^ii') so I figured I'd add it now. I used to have prefork but switched to worker when someone suggested it might help. The error was occurring with prefork and in worker exactly the same.
ii apache2 2.2.16-1ubuntu3.5 Apache HTTP server metapackage
ii apache2-mpm-worker 2.2.16-1ubuntu3.5 Apache HTTP Server - high speed threaded model
ii apache2-utils 2.2.16-1ubuntu3 utility programs for webservers
ii apache2.2-bin 2.2.16-1ubuntu3.5 Apache HTTP Server common binary files
ii apache2.2-common 2.2.16-1ubuntu3.5 Apache HTTP Server common files
ii libapache2-mod-wsgi 3.2-2 Python WSGI adapter module for Apache
Edit2: Looks like this has to do with an Encrypted Home Directory, which I was unaware of I had on this server. I can't post an answer for it yet due to Reputation, but I will when I can so other people with the same issue will be able to figure out the deal much quicker.
After two days of searching, I found someone else with the same issue.
Basically, the server was setup with an Encrypted Home Directory (unbeknownst to me), so when I was logged in and testing everything went as expected. But as soon as I wasn't, the home directory was no longer available to Apache.
Hopefully, if anyone else runs across this issue this post will help them out. The quickest way I found to see if you have an Encrypted Home Directory is to run:
$ mount | grep ecryptfs
The process of "unencrypting" your home directory seemed painful, so I resolved this issue by moving my Django directory outside of /home and into /var/www
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Awake is called when the script instance is being loaded..
#pragma strict private var target: GameObject; function Awake() { target = GameObject.FindWithTag("Player"); } .
#pragma strict // Make sure that Cube1 is assigned this script and is inactive at the start of the game. public class Example1 extends MonoBehaviour { function Awake() { Debug.Log("Awake"); } function Start() { Debug.Log("Example1"); } function Update() { if (Input.GetKeyDown("b")) { print("b key was pressed"); } } }:
#pragma strict public class Example2 extends MonoBehaviour { public var GO: GameObject; function Start() { Debug.Log("Example2"); } private var activateGO: boolean = true; function Update() { if (activateGO == true) { if (Input.GetKeyDown("space")) { Debug.Log("space key was pressed"); GO.SetActive(true); activateGO = false; } } } } cannot be a co-routine.
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Shane's Vitarana's thoughts on technology tag:shanesbrain.net,2009:mephisto/ Mephisto Noh-Varr 2008-10-10T04:42:42Z Rants and annoucements about Ruby, Rails, and social software.41.900332-87.669276 shane tag:shanesbrain.net,2008-10-10:6033 2008-10-10T00:45:00Z 2008-10-10T04:42:42Z iPhone FriendFeed Client Open-Sourced <p>When the iPhone <span class='caps'>SDK</span> was first released in March, I got my feet wet with Objective-C and the <span class='caps'>SDK</span> by building a FriendFeed client. I never got around to finishing it, and don’t want it to languish away on my Mac. So I’m releasing it to you guys under the <span class='caps'>MIT</span> license. It was last developed on an early beta of 2.0, but has been updated to compile using the released 2.0 <span class='caps'>SDK</span>..</p> <p>FriendFeed Touch is hosted on GitHub: <a href=''></a></p> <p>Warning: This is not release quality software. I leave it as an exercise for the reader to finish.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-10-08:6035 2008-10-08T18:28:00Z 2008-10-10T04:53:40Z Speaking at iPhoneLive 2008 <p>I’m going to be speaking at <a href=''>iPhoneLive 2008</a> in San Jose, on November 18th, O’Reilly’s new conference for iPhone developers. Now that the <span class='caps'>NDA</span> has been lifted, this conference is going to be a chock full of information. The <a href=''>line-up</a> looks amazing, and includes some of the best speakers from <a href=''>iPhoneDevCamp</a> and <a href=''>C4</a>.</p> <p>I’m going to talk about criteria for successful iPhone apps, and about the Audio APIs available in the <span class='caps'>SDK</span>. If you would like to hear about anything else, please leave a comment here or <a href=''>send me a tweet</a>. I’m looking forward to meeting you and hearing your questions and ideas.</p> <p>Early registration ends on 10/14, so <a href=''>sign up now</a>. If you register now, you’ll get an additional 20% off early registration with discount code ‘ip08gd20’.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-07-31:3774 2008-07-31T03:51:00Z 2008-07-31T03:52:44Z Rails on Facebook Published <p>I’m happy to announce the publication of my first <span class='caps'>PDF</span> book, <a href=''>Rails on Facebook</a>, along with co-author <a href=''>David Clements</a>.</p> <p><a href=''><img src='' alt='' /></a></p> <blockquote> <p>“This 67 page <span class='caps'>PDF</span> will get you up and running with the Facebooker plugin. You’ll learn to install and configure the plugin. You’ll send <span class='caps'>HTML</span>, Javascript, and images to Facebook (with caching). You’ll learn about the parts of Facebook that you can augment. Finally, you’ll learn how to write tests for your Facebook application”. —Peepcode Press</p> </blockquote> <p>Like all <a href=''>Peepcode</a> books, there’s no fluff here. Just straight ahead how to make a Facebook application using Ruby on Rails. David and I made sure it covers the latest <span class='caps'>API</span> additions and changes.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-07-09:3456 2008-07-09T18:29:00Z 2008-07-31T03:56:33Z Using Xcode with Git <p>For Xcode and Git to work smoothly with each other, you need to make sure Git treats Xcode project files properly. You do this by configuring Git via .gitignore and .gitattributes. Create these files in your repo’s root folder and add the following lines:</p> <p>.gitignore</p> <code> <pre> # xcode noise build/* *.pbxuser *.mode1v3 # old skool .svn # osx noise .DS_Store profile </pre> </code> <p>.gitattributes</p> <code> <pre> *.pbxproj -crlf -diff -merge </pre> </code> <p>The line in .gitattributes treats your Xcode project file as a binary. This prevents Git from trying to fix newlines, show it in diffs, and excludes it from merges. Note that you will still see it shown as a conflict in merges, although the file won’t have changed. Simply commit it and things should be good.</p> <p>Thanks to <a href=''>Jonathan Wight</a> and <a href=''>Chris Double</a>.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-04-08:2256 2008-04-08T07:03:00Z 2008-04-13T21:35:34Z iPhone App: FriendFeed Touch <p> [This video demo has been removed] </p> <p>Here’s my first iPhone app demo, a client for FriendFeed, created with the official <span class='caps'>SDK</span>..</p> <p.</p> <p>When released, this will probably go under a different name than FriendFeed Touch, since it has to be obvious that third-party apps aren’t affiliated with FriendFeed.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-04-04:2224 2008-04-04T18:36:00Z 2008-04-04T18:37:01Z iPhone Development <p>For those who are <a href=''>following me on Twitter</a>, it’s quite obvious that I’ve been playing with the iPhone <span class='caps'>SDK</span>.</p> <p>I’ll be posting some video demos of app prototypes soon. Stay tuned.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-02-11:1645 2008-02-11T17:15:00Z 2008-02-11T17:17:45Z Spacer, Yes with an 'e', Released <p><img src='' alt='' /></p> <p><strong><span class='caps'>DESCRIPTION</span></strong></p> <p>Ruby <span class='caps'>API</span> for the MySpace Platform <span class='caps'>REST API</span></p> <p><strong><span class='caps'>FEATURES</span>/PROBLEMS</strong></p> <ul> <li>Implements v1.0 of the MySpace Platform <span class='caps'>REST API</span></li> <li>Uses OAuth to securely authenticate with MySpace</li> <li>Uses <span class='caps'>JSON</span> for minimal transport footprint</li> </ul> <p><strong><span class='caps'>PLAY</span></strong></p> <p><img src='' alt='' /></p> <code><pre> @myspace = Spacer::Client.new(api_key, secret_key) user = @myspace.user('3454354') puts user.interests.music puts user.photos.first.caption </pre></code> <p><strong><span class='caps'>REQUIREMENTS</span></strong></p> <ul> <li>OAuth</li> <li>ActiveSupport</li> <li>Mocha (for testing)</li> </ul> <p><strong><span class='caps'>INSTALL</span></strong></p> <ul> <li>sudo gem install spacer</li> </ul> <p><strong><span class='caps'>DOCUMENTATION</span></strong></p> <p>Rubyforge: <a href=''></a> (submit bugs here)</p> <p>RDocs: <a href=''></a></p> <p>Goolge Group: <a href=''></a></p> <p><strong><span class='caps'>NOTES</span></strong></p> <p>MySpace is still actively making changes to their <span class='caps'>API</span>, so this is far from a 1.0 release. However, as of the day of this post, it implements all the features of their <span class='caps'>REST API</span>.</p> <p>Thanks to Ken Pelletier for coming up with the very creative name.</p> <p><span>photo credits: <a href=''>bub.blicio.us</a> and <a href=''>Scott Beale / Laughing Squid</a></span></p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-02-11:1653 2008-02-11T07:57:00Z 2008-02-11T08:08:41Z Introducing YouTube-G <p><a href=''>Walter Korman</a> and I are proud to release youtube-g version 0.4.1.</p> <p>youtube-g is a pure Ruby client for the YouTube GData <span class='caps'>API</span>. It provides an easy way to access the latest YouTube video search results from your own programs. In comparison with the earlier Youtube search interfaces, this new <span class='caps'>API</span> and library offers much-improved flexibility around executing complex search queries to obtain well-targeted video search results.</p> <p>More detail on the underlying source Google-provided <span class='caps'>API</span> is available at:</p> <p><a href=''></a></p> <p><strong><span class='caps'>FEATURES</span></strong></p> <p>Aims to be in parity with Google’s YouTube GData <span class='caps'>API</span>. Core functionality is currently present—work is in progress to fill in the rest.</p> <p><strong><span class='caps'>USE</span></strong></p> <p>Create a client:</p> <pre><code>require 'youtube_g' client = YouTubeG::Client.new</code></pre> <p>Basic queries:</p> <pre><code>client.videos_by(:query => "penguin") client.videos_by(:tags => ['tiger', 'leopard']) client.videos_by(:categories => [:news, :sports]) client.videos_by(:categories => [:news, :sports], :tags => ['soccer', 'football']) client.videos_by(:user => 'liz')</code></pre> <p>Standard feeds:</p> <pre><code>client.videos_by(:most_viewed) client.videos_by(:top_rated, :time => :today)</code></pre> <p>Advanced queries (with boolean operators OR (either), <span class='caps'>AND</span> (include), <span class='caps'>NOT</span> (exclude)):</p> <pre><code>client.videos_by(:categories => { :either => [:news, :sports], :exclude => [:comedy] }, :tags => { :include => ['football'], :exclude => ['soccer'] })</code></pre> <p><strong><span class='caps'>DOCUMENTATION</span></strong></p> <p>Rubyforge project: <a href=''></a></p> <p>RDoc: <a href=''></a></p> <p>Google Group: <a href=''></a></p> <p><strong><span class='caps'>INSTALL</span></strong></p> <ul> <li>sudo gem install youtube-g</li> </ul> <p>Changes:</p> <p>0.4.1 / 2008-02-11</p> <ul> <li>Added 3GPP video format [shane]</li> <li>Fixed tests [shane]</li> </ul> <p>0.4.0 / 2007-12-18</p> <ul> <li>Fixed <span class='caps'>API</span> projection in search <span class='caps'>URL</span> [Pete Higgins]</li> <li>Fixed embeddable video searching [Pete Higgins]</li> <li>Fixed video embeddable detection [Pete Higgins]</li> <li>Fixed unique id hyphen detection [Pete Higgins, Chris Taggart]</li> </ul> <p>0.3.0 / 2007-09-17</p> <ul> <li>Initial public release</li> </ul> <p><strong><span class='caps'>NOTES</span></strong></p> <p><em>Our previous library, youtube, has been deprecated. Please use youtube-g from now on.</em></p> <p>Who can guess what the name youtube-g is in reference to? Hint: Like us, you probably used <a href=''><span class='caps'>BBS</span>’s</a> before the days of the web, when wide adoption of <span class='caps'>TCP</span>/IP was still a few years away.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2008-02-11:1644 2008-02-11T00:54:00Z 2008-02-11T02:09:21Z Super Rewards Client API Released <p><strong><span class='caps'>DESCRIPTION</span></strong></p> <p>A Ruby client for the $uper Rewards <span class='caps'>API</span> by <span class='caps'>KITN</span> Media, the Facebook monetization tool.</p> <p><strong><span class='caps'>FEATURES</span></strong></p> <ul> <li>Aims to implement all the functionality of the $uper Rewards service</li> </ul> <strong><span class='caps'>USE</span></strong> <code><pre> offer_code = SuperRewards::Client.offers_display(:iframe, uid) points = SuperRewards::Client.get_points(uids).first.user.points </pre></code> <p><strong><span class='caps'>REQUIREMENTS</span></strong></p> <ul> <li><span class='caps'>API</span> / Secret keys for the $uper Rewards service</li> <li>Shoulda gem (for testing)</li> </ul> <p><strong><span class='caps'>INSTALL</span></strong></p> <ul> <li>sudo gem install superrewards</li> </ul> <p><strong><span class='caps'>DOCUMENTATION</span></strong></p> <p>Rubyforge: <a href=''></a></p> <p>RDocs: <a href=''></a></p> <p><strong><span class='caps'>NOTES</span></strong></p> <p>I released this on December 17th, 2007, so the service may have changed since then. All the tests still pass as of the day of this post.</p> <p>Thanks to Eugene from <span class='caps'>KITN</span> Media for helping me with debugging and testing, and Jason Bailey for moral support.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-10-27:619 2007-10-27T06:38:00Z 2007-10-27T17:24:01Z YouCast: White-label video sharing site <p>YouCast is a Ruby on Rails video sharing application that you host on your own servers. It can be rebranded easily for your company or used as is.</p> <p>Main features:</p> <ul> <li>Upload videos, images, and music via web or <b>mobile phone</b> via <span class='caps'>SMS</span>/MMS attachment</li> <li>Create a playlist of your videos, images, and music</li> <li>Play your media in a Flash player</li> <li>Get the code for the player to embed in any site (myspace, blog, etc)</li> <li>Generates thumbnails for videos</li> <li>Multi-user support with user login and user management</li> <li>Export your playlist in <a href=''><span class='caps'>XSPF</span>/Spiff</a> format</li> </ul> <p>Tech specs:</p> <ul> <li>Ruby on Rails application designed with RESTful methodology</li> <li>Supports all major video and image formats, and mp3 for music</li> <li>Encodes all video to Flash</li> <li>Uses <a href=''><span class='caps'>MMS2R</span></a> for mobile media processing</li> <li><a href=''><span class='caps'>XSPF</span>/Spiff</a> format used for playlists for maximum portability</li> </ul> <p>What you get:</p> <ul> <li>Full source code</li> <li>10 hours of free consulting, including help with installation and migration</li> <li>Option to hire me for additional consulting</li> </ul> <p>What can you do with YouCast?</p> <ul> <li>Create an internal video sharing site for your company or small business</li> <li>Use it as a base for your own video-related site</li> <li>Merge it with your existing site to add video and mobile media support</li> <li>Re-create YouTube to impress your friends</li> </ul> <p>How much does it cost?</p> <ul> <li>YouCast will cost a yet-to-be-determined one-time fee, which includes free updates to that version. I will determine the cost once I get a better idea of demand.</li> </ul> <p>Email me at the address in the <a href=''>About Me page</a> if you are interested in seeing a demo and/or purchase.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-10-10:485 2007-10-10T21:30:00Z 2007-10-10T21:30:27Z Video Jukebox Facebook Application Launched <p><img src='' alt='' /></p> <p><a href=''>Video Jukebox</a> finds music videos of your favorite music and lets you put them on your profile.</p> <p>You must have the favorite music section in your profile filled out for Video Jukebox to figure out what you like.</p> <p>This uses a pre-release version of <a href=''>youtube-g</a>, a Ruby <span class='caps'>API</span> for the <a href=''>GData</a> version of YouTube’s <span class='caps'>API</span>.</p> <p>Thanks to <a href=''>Walter Korman</a> for brainstorming the idea with me and Jesus Duran for help with the name.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-09-01:432 2007-09-01T19:28:00Z 2007-09-13T07:56:31Z MyFitBuddy.com Launched! <p><img src='' alt='MyFitBuddy.com logo' /></p> <p>I’m pleased to announce the launch of <a href=''>MyFitBuddy.com<. </p> <p>I mainly built this site for myself, as I wanted a super simple way to keep a record of my workouts and see graphs of my improvement. I thought it would be a great idea for a social site, as many studies have shown that people exercise more when they have a workout buddy or do it as part of a group. In <a href=''>MyFitBuddy.com</a>, you will be motivated to exercise by seeing the activity of your friends and others on the site. </p> <p>Some of the other interesting features on the site include user generated exercise information from Wikipedia, and videos of exercise form from YouTube. Soon I’ll be adding weight and calorie tracking, as well as the ability to SMS text in your workouts from your mobile phone. The site is currently completely free to use.</p> <p>Give it a spin and help me knock off some bugs. I’d love to hear feedback and any suggestions.</p> <p><em>Update:</em> <a href=''>KillerStarups</a>, a sort of digg for startups, is the first to review MyFitBuddy.com. If you are in a generous mood, <a href=''>please vote for it</a>.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-08-14:403 2007-08-14T18:57:00Z 2007-08-14T19:12:53Z Pardon the Dust <p>I recently migrated this blog from Typo to Mephisto and have a few cleanup activities to perform. Markdown formatting has to be converted, sidebar stuff has to be added, and the design needs some minor tweaks to get things looking like how they did before. So sorry for the temporary ugliness.</p> <p>I’ve been really busy working on client projects and trying to get my own startup launched, and therefore have been falling behind on the open source work. Thanks to those who sent me contributions to the youtube gem. I plan on making one more release before working on version 2. youtube2 will use the GData format since YouTube is changing the <span class='caps'>API</span> to fit more with Google’s other APIs. It is slated for release later in the year.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-06-12:38 2007-06-12T22:42:05Z 2007-07-17T19:27:47Z > YouTube Gem 0.8.6 Released <p>This is mainly a bugfix release but also makes it easier to search for videos by category. Searching by category greatly helps in finding videos that are more relevant. You can now do:</p> <pre><code>videos = videos_by_category_and_tag(YouTube::Category::MUSIC, 'bush')</code></pre> or if you wanted to: <pre><code>videos = videos_by_category_and_tag(YouTube::Category::NEWS_POLITICS, 'bush')</code></pre> <p>For more details check out the <a href=''><span class='caps'>CHANGELOG</span></a>. Thanks to all the contributers, <a href=''>Walter Korman</a>, <a href=''>Lucas Carlson</a>, Rob Tsuk, and Thomas Cox.</p> <p>Related posts:<br /></p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> shane tag:shanesbrain.net,2007-05-30:37 2007-05-30T13:33:10Z 2007-07-17T19:27:47Z Managing database.yml with Capistrano 2.0 <p>Jeremy Voorhis posted <a href=''>a really great Capistrano recipe for managing database.yml</a> which dynamically creates a database.yml file in your shared directory on setup, and symlinks your app’s database.yml once it’s deployed. This is great if you don’t version control your database.yml file for security reasons or working with multiple developers. </p> <pre><code>changes the syntax for task callbacks and gets rid of the useful render method. However, using <a href=''>ERb</a>, Ruby's built-in templating system, isn't much more difficult than using the old render method. Here is Jeremy's script updated for Capistrano 2.0 using ERb and the new namespaced callback syntax.</code></pre> <pre><code>require 'erb' before "deploy:setup", :db after "deploy:update_code", "db:symlink" namespace :db do desc "Create database yaml in shared path" task :default do db_config = ERB.new <<-eof base:><<:><<:><<:></code></pre> <p>Until I get better syntax highlighting for this blog, check out the <a href=''>Pastie for the color version</a>. For more info on whats new in Capistrano 2.0, check out <a href=''>Jamis’ preview</a> and <a href=''>Geoff’s post</a>. Also, props to Jamis for suggesting I use ERb directly.</p> <p><b>Update:</b> Updated code to use its own :db namespace instead of the default one. The database yaml file will be created by the default :db task, and the symlink will be created by the db:symlink task. Note how namespaces in Cap 2.0 allows us to have two symlink tasks, one in the deploy namespace and the other in db.</p> <div class="feedflare"> <a href=""><img src="" border="0"></img></a> <a href=""><img src="" border="0"></img></a> </div> | http://feeds.feedburner.com/ShanesBrainExtension | crawl-002 | refinedweb | 3,560 | 55.54 |
[System design] From service to architecture
The new series refers to the system design explanation of the nine chapters algorithm
Article Directory
- Specification of system design interview
- 4S analysis method
- System design-Twitter design newsfeed
- storage storage-PUll model (drop down)
- storage storage-PUSH model (send)
- Model comparison
- upgrade
- celebrity effect
- Attention and clearance
- Store likes
- Design user system-understand database and cache
- The impact of different QPS on storage systems
- Features of the user system
- Friendship Store
- Prevent single point of failure (slicing, backup)
- Consistent Hash Algorithm
- Backup and copy
- System Design————Design a short URL system
- Short URL algorithm
- Optimization (how to speed up)
- Custom URL
- Is it necessary to ensure one-to-one correspondence between long and short URLs?
- 301 or 302 jump
- System Design-Geographical Information Service
- How to store and query geographic location information
- Implement GeoHash algorithm
- System design-real-time chat system
- The flow of users sending and receiving messages
- System design-how to limit current
- Google's Ratelimiter source code
- System design-datadog, website visit data statistics
- System design-web crawler system
- Implementation
- Upgrade strategy
- System design-spelling association
- Distributed File System (GFS)
- Real question
- Map Reduce (counting in big data scenarios)
- System Design of Map Reduce
- Distributed database Bigtable
- Read and write process of the complete system
- Clustered Bigtable+GFS
Specification of system design interview
Feasible solutions are 25%, special problems in specific scenarios are 20%, analysis capabilities are 25%, trade-offs are 15%, and knowledge reserves are 15%.
According to my understanding of the school’s enrollment requirements, first examine our communication skills in such questions, whether we can understand the idea of the interview, and can we clearly express our thoughts. The second is to look at the individual's ability to think about problems, including understanding the scene of the problem, abstracting a problem, and proposing a feasible solution. Try to grasp the core of the problem as quickly as possible. If you further upgrade, you should also show your comprehensiveness in thinking about the problem as much as possible. The feasible solution is not perfect. We can further analyze the advantages and disadvantages of this method. And give your own upgrade strategy. Here is the role of trade-offs and knowledge reserves.
4S analysis method
- Scenario scenario: Analyze clearly what scenarios and services are needed. QPS, DAU, Interface
- Service service: The core module of the large system is split.
- Storage: The storage of data. Here design to the object-oriented design, how to design the table, what kind of structure is used to store data. Data, SQL, Nosql, File System
- Scale upgrade: scalability, what are the problems with the current feasible solution, and how to upgrade. (Upgrade, maintenance-robustness, single point of failure; scalability, coping with surge in traffic)
Scenario analysis: Given some reference, the daily active users of Twitter are about 150M+. Choose some core services, post a tweet, TimeLine, News Feed, etc. Here you can make some reasonable estimates, including the number of concurrent users (daily active * average number of requests per user / number of seconds in a day), peak value (three times the average), read and write frequency (300k, 5k)
The core of the service is replay and merger, designing services for each requirement, and merging the same services.
Storage: Relational database: suitable for user information, etc.; non-relational: suitable for tweets, social graphs, etc.; file system: suitable for pictures and videos, etc. A reasonable design table is also needed here.
System design-Twitter design newsfeed
Similar needs still exist with Weibo, Moments, etc. The core of the new thing system is the relationship between attention and being followed, and what everyone sees is different.
storage storage-PUll model (drop down)
Idea: The idea of K-way merging is adopted. When the user wants to view, the first 100 items that the user pays attention to are obtained, and then merged to obtain topK. Similar to K road merge.
Complexity analysis: It is very slow when the user obtains the information flow, and it needs to read the database N times; when it is sent quickly, it is directly written to the DB once
Disadvantages: It is slower every time you look at a new event stream. Need to read the sort from the database. User experience is slightly worse
storage storage-PUSH model (send)
- Idea: Each user creates a list to store everyone's feed news. After the user sends a tweet, it is sent to each user's News feed. (Keywords, fanout, fanout). In this way, only the first 100 messages need to be read.
- Complexity analysis: Reading messages is fast, one DB read. Sending tweets is troublesome, and N fans need to perform N DB writes. But this step can be done asynchronously without waiting.
- Defect: Not timely, because there may be many followers. There is a delay, which may be a problem for celebrities’ social networks.
Model comparison
Facebook-pull; Twitter-pull; Ins-Push+pull It can be seen that the pull method is the mainstream. Because for applications, user experience is the core, so issues such as latency and zombie fans must be considered
Push is suitable for two-way attention, such as a circle of friends. The fans are not large, the real-time performance is not high, and the resources are very small. Pull is suitable for high real-time, one-way attention to celebrity issues, and Weibo.
upgrade
- PULL method: add a cache before the DB, and cache the tweets of some users. The cache maintains the message queue of a user in the timeline . In this way, N times of BD becomes N times of cache request. And you can make a trade-off, and use LRU to eliminate outdated caches. Cache each user’s News Feed and directly maintain the user’s new feed.
- PUSH method: The push model puts the NewsFeed model in memory. The cost of this is actually not high.
celebrity effect
For hot stars, there is a lot of pressure to fan out. It can be solved by adding a server in a short time. Don't change the model when you come up here, it will cost a lot.
- Push+pull: Ordinary users still push, while celebrity users use the pull method. Star users maintain their own timeline, and fans need to make their own songs.
Attention and clearance
After following a user, merge his Timeline into your News Feed asynchronously. After Unfollow a user, asynchronously remove his Tweets from your News Feed. Asynchrony allows users to get feedback quickly, but the disadvantage is that it may delay the effect.
Store likes
Design user system-understand database and cache
Design the user system, including the realization of registration, login, user information query, etc. The difficulty lies in the storage of data , including the storage of friend relationships .
4S analysis
- Scenario: registration, login, query, user information modification. Among them, query is the biggest demand, and the QPS to be supported is the highest.
- Service: Registration and login module, module for querying user information, responsible for storage of friend relations
The impact of different QPS on storage systems
- SQL databases such as MySQ: probably support up to 1K qps
- Hard disk Nosql such as MongoDB can support up to 10K
- 100k performance of Redis/Memcached in-memory database
Features of the user system
Read a lot and write very little. For a system that reads more and writes less, you must consider using Cache optimization . The system for human use is more writing and less writing, and the high probability of using it for machines is writing more and less reading.
For the use of cache: be sure to first get in the db, and then set from the cache. When deleting, delete it from the cache first, and then update it in the DB.
Ensure user login: use cookie or session. Users will bring their own cookies when sending visits to the server.
This Session Table can be stored in the cache or in the DB. If there are a lot of users, you can use Cache optimization. However, you need to be wary that putting all of them in the cache may cause a large-scale re-login after a power failure, and the database pressure will increase sharply.
Friendship Store
It can be non-repetitive storage, numbering the user, with the small number in the front and the large number in the back; or it can be repeated storage, where A’s friends have B, and B also has A.
If transactions are required, caches are generally not used.
Prevent single point of failure (slicing, backup)
Data splitting is to ensure that a certain library is down, and it will not cause the website to be 100% unavailable. You can use sub-database and sub-table. Vertical splitting is actually splitting according to the business, disassembling large tables into small tables, and try to use small tables for some hot data. Prevent lock problems. Horizontal segmentation is to consider the splitting of some huge tables. The key here is the selection of the sub-table key and the method of sub-table. Table sharding keys generally need to be related to business application scenarios. Table sharding methods include simple modulo, etc. Crude methods have problems such as hot data and not easy to expand. A better method is to use consistent hashing. This can minimize the trouble of re-separation after expansion.
Data backup is to consider master-slave backup, cluster. You can also write to the main library and read from the library to reduce pressure.
Consistent Hash Algorithm
Regarding the entire hash interval as a ring, the size of the ring is [0, 2 64 − 1] [0, 2^{64}-1] [ 0 ,26 4−1 ]. And introduced the concept of virtual nodes (Virtual nodes). Each physical machine corresponds to 1000 points on the ring. When we add a piece of data, we calculate the hash value of the key to correspond to a point on the ring. Find the first virtual node storage clockwise. When a new machine is added for data migration, the 1000 virtual nodes all ask for data from their first virtual node clockwise.
- Why is it 1000 points?
Because if it is one point, it is easy to be uneven. For example, if we only have three servers, 3,000 points are definitely more even than 3 points. Why not more? There is a trade of here. We need to store the position of all virtual nodes on the ring. The storage form is using TreeMap, which is essentially the use of red-black trees. O (l o n g n) O(longn) O ( l o n g n )Quickly find the first virtual node that is greater than the current data hash value within a period of time. Therefore, too many nodes will increase the cost of storage.
Backup and copy
Backups are generally periodic, and replication is generally real-time. Let's take Mysql's master-slave model as an example. The principle is that any operation of Write Ahead Log, which is the main library of sql, will be recorded in the log, and then this log will be sent to the slave node through a dedicated io thread. Of course , the issue of master-slave delay needs to be considered here
System Design————Design a short URL system
The short URL system is to map a relatively long URL such as to
- Scenario: Realize the mutual conversion from long URL to short URL. And you can enter the short url and then jump to the long url correctly.
- Requirements: QPS+Storage can also estimate QPS based on DAU, and consider the peak situation to select a suitable storage system. The required hard disk space can be calculated based on the storage required by the URL.
- Service: Only a simple URL conversion
- Storage: Both sql and nosql are available.
Short URL algorithm
- Use the last 6 bits of the hash function directly (not feasible). Although it is very fast, there will be collisions that cannot be resolved.
- Randomly generate a short URL and use the database to remove duplicates. The implementation is very simple, but it will become slower and more serious as the short URL increases later.
- Base 62 conversion . The URLs that can be used include (0-9, az, AZ), a total of 62. Can be changed to 62 hexadecimal. Each URL corresponds to an integer. The integer is the primary key of the database table and is self-increasing. This 6-digit number can store 57 billion content. The advantage is high efficiency, but the disadvantage is that it relies on the self-incrementing primary key and can only use the sql database.
If you use a randomly generated method . If using a SQL database, we need to index the two URLs separately for quick search. Or create two tables in the nosql database to store the corresponding key-value pairs.
If the method of hexadecimal conversion is adopted . You must use an sql database with an auto-incrementing primary key. Only the primary key and the long URL are required, and the short URL can be converted from the primary key.
Optimization (how to speed up)
First, you can use the cache layer to speed up the reading efficiency , and store commonly used converted long and short URLs. Some elimination algorithms can be used here.
Secondly, you can use geographic location information to speed up , optimize server access speed, resolve users from different regions to different servers through DNS, and further, you can store the Chinese website in the Chinese database, and the US website in the US database.
We also need to solve the problem of how to expand. The bottleneck of this system design is that it is too busy, not that it can't be saved . Therefore, we can use the method of horizontal sub-table , but this is designed to the selection of sub-table keys . There are contradictory factors. If you select ID as the sub-table key, you cannot quickly query the long URL in that sub-database, and you can only use the broadcast method. A better way is to introduce an identification bit , such as AB123->0 AB123, the 0 is obtained according to (Hash(long_URL)%62), so that it can be found quickly. At the same time, for the case of sub-database, we also need to use consistent hashing .
For the global self-incrementing ID after sub-table, you can use a database to realize the operation of self-incrementing ID, or use ZooKeeper. In fact, this is not necessarily a single point, it can be divided into single number, double number, etc.
Custom URL
We need to create a new CustomURLTable to store the abbreviations we want to define ourselves, instead of adding a column to the original table, which will cause a lot of holes.
Is it necessary to ensure one-to-one correspondence between long and short URLs?
The long URL corresponding to the short URL must be corresponding, but the short URL corresponding to the long URL is completely unnecessary. We can use a simple kv pair and set the expiration time to 24h. When the long URL comes, check it in the cache first, and return it if there is one, otherwise, just give a new short URL.
301 or 302 jump
This is also an interesting topic. First of all, of course, examine a candidate's understanding of 301 and 302. Understanding of browser caching mechanism. Then it is to examine his business experience. 301 is a permanent redirection, and 302 is a temporary redirection. The short address will not change once it is generated, so using 301 is consistent with http semantics. At the same time, the pressure on the server will also be reduced to a certain extent.
But if 301 is used, we cannot count the number of clicks on the short address. And this number of clicks is a very interesting data source for big data analysis. There are many things that can be analyzed. So although choosing 302 will increase the server pressure, I think it is a better choice.
Of course, we generally do not allow short URLs to expire.
System Design-Geographical Information Service
Many apps need to use location information, and then collect some information closest to your current location and feed it back to the user. The typical type is Didi, Dianping and other local life apps.
- Scenario: The system needs to know the driver's location in real time, that is, the driver's location needs to be reported; when the user requests a taxi, it needs to match the nearest nearby driver based on the user's current location. It can be analyzed from this that uber should be a write-intensive requirement, because we need to synchronize the driver's position every 4s. Assuming a 200k driver, the write request per second is 50k, and the peak value can reach 150k. For storage, if each location is saved, 200k 86400/4 100bytes = 0.5T per day. If only the current position is recorded, it is probably 200k*100bytes=20M;
- Service: Two large modules need to be included, one is location record and the other is location matching.
- Storage: Obviously, the storage of the location is high-write, and the query of the order is high-read. And the storage of geographic information is relatively simple, you can use kv key-value pairs, here you can use high-speed redis. For the query of order information because the comparison table will be more complicated, it is better to use the sql database here.
The OOD design of the order table and the driver table in Sql can be as shown in the figure below.
How to store and query geographic location information
Two commonly used algorithms, one is the google S2 algorithm, which uses the Hilbert curve to map the address space to 2 64 2^{64} 26 4Integers. Two points that are similar in space are generally similar in integers. The library functions of this method are relatively rich and more accurate. Another method is to use GeoHash . The algorithmic idea converts the geographic location into a string. The more two strings match, the closer the two points are generally. The algorithm is a bipartite map, and the specific code implementation is implemented below.
For geographic location storage, you can use sql database, because we often search, so we need to index geohash, and use LIKE to query. However, this is not very consistent with the military regulations of SQL. First, the indexed column should not be inserted frequently, which will cause the appearance of index holes and waste space. Secondly, LIKE query is relatively slow, generally not recommended.
Since we are writing frequent operations, we can use redis to create a simple key-value pair, where the key is the position and the value is the set of the driver number. For example, if the location of the Driver is 9q9hvt, it can be stored in the 3 keys of 9q9hvt, 9q9hv, and 9q9h, because the accuracy of the four positions is already 20km, so you won't be able to take a car over 20km. For the 6-digit agreement, it is already within one kilometer, and it is accurate enough. If the match is successful (the distance is close enough, the driver is free, the driver will take the order), the system returns the driver's number. Then go to the database or another redis table to query the specific latitude and longitude information of the driver. That is, we need to get the location of the nearby driver from the geographic location, and we also need to know the id of the driver to get the location
- Expansion: To solve the single point of failure problem, the performance bottleneck that can be solved through multiple redis. Of course, it is also necessary to allocate traffic reasonably. A better idea is to divide it according to the city. In fact, it is a mathematical problem of judging whether a point is in a polygon. How to determine whether the user is in the airport area or not, you can first determine the city, and then find whether the user is in the promotion area in the headset content.
Implement GeoHash algorithm
Base32, 0-9, az remove (a, i, l, o). The Piano curve used here is actually used for coverage. When converting to a character string, it usually crosses the latitude and longitude information. The reason for choosing 32 bits is that this number is exactly 2 to the 5th power. It is also conducive to calculation under the condition of ensuring accuracy.
Since GeoHash divides the area into regular rectangles and encodes each rectangle, it will cause the following problems when querying nearby POI information. For example, the red point is our location, and the green two points are nearby. Two restaurants, but when you query, you will find that the GeoHash code of the farther restaurant is the same as ours (because they are in the same GeoHash area), while the GeoHash code of the closer restaurant is inconsistent with us. The cases where the distance is close but the codes are not the same often occur at the boundary.
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To solve this problem, we need to consider all the eight surrounding squares, traverse both the own square and the points in the surrounding eight squares, and then return to the points that meet the requirements. So how do you know the prefix of the surrounding squares? Carefully observe the adjacent squares, we will find that the two small squares will differ by 1 in the binary code of the longitude or latitude; after we parse the binary code through the GeoHash code, the longitude or latitude (or both) Add one to the binary code and combine it again into a GeoHash code.
We already know that the existing GeoHash algorithm uses the Peano space filling curve. This curve will produce abrupt changes, causing the problem that the codes are similar but the distances may vary greatly . Therefore, when querying nearby restaurants, first select the similar GeoHash codes. POI point, and then calculate the actual distance.
public class GeoHash { /* * @param latitude: one of a location coordinate pair * @param longitude: one of a location coordinate pair * @param precision: an integer between 1 to 12 * @return: a base32 string */ private String _base32 = "0123456789bcdefghjkmnpqrstuvwxyz"; // base32算法 public String encode(double latitude, double longitude, int precision) { // write your code here // 实现GeoHash算法 涉及到的函数包括地理位置的转换为二进制，二进制转换为字符串 // 然后根据字符串的匹配程度可以知道位置的误差信息 //String _base32 = "0123456789bcdefghjkmnpqrstuvwxyz"; // base32算法 String x = getBin(latitude, -90.0, 90.0); String y = getBin(longitude,-180.0, 180.0); StringBuffer sb = new StringBuffer(); for (int i = 0;i<30 ;i++){ sb.append(y.charAt(i)); sb.append(x.charAt(i)); } StringBuffer ans = new StringBuffer(); String res = sb.toString(); for (int i = 0;i<60;i+=5){ ans.append(_base32.charAt(Integer.parseInt(sb.substring(i,i+5),2))); } return ans.toString().substring(0,precision); } private String getBin(double position, double left, double right){ StringBuffer sb = new StringBuffer(); // 这里为什么是30呢？因为我们最终的字符串的长度是12，因此二进制需要有12*5=60 // 因为是由经纬度拼接成的，所以各自都需要时30 for(int i = 0;i<30;i++){ double mid = (left+right)/2.0; if (position<=mid){ sb.append("0"); right = mid; }else{ sb.append("1"); left = mid; } } return sb.toString(); } public double[] decode(String geohash) { // write your code here //String _base32 = "0123456789bcdefghjkmnpqrstuvwxyz"; int[] mask = {16, 8, 4, 2, 1}; double[] x = {-180, 180}; double[] y = {-90, 90}; boolean is_even = true; for (int i = 0; i < geohash.length(); i++){ int index = _base32.indexOf(geohash.charAt(i)); for(int j = 0; j<5;j++){ // j之所以是5，因为我们还是32个base if (is_even){ refine_interval(x, index, mask[j]); }else{ refine_interval(y, index, mask[j]); } is_even = !is_even; } } double[] location = {(y[0]+y[1])/2.0, (x[0]+x[1])/2.0}; return location; } private void refine_interval(double[] pos, int val, int mask){ // 判断当前位是向左还是向右 if((val & mask) != 0){ pos[0] = (pos[0] + pos[1])/2.0; }else{ pos[1] = (pos[0] + pos[1])/2.0; } } }
System design-real-time chat system
The basic problem is obvious, which is to design a WeChat type design.
- Scenarios and main functions: send messages between users, group chats, user status settings. Facebook's data is 1 billion monthly active users, and the daily active data is about 75%, so there can be 75 million daily active users. Therefore, we need to design a million-level system, assuming a user sends 20 messages a day, QPS=100M*20/86400~20K. Storage, each record is about 30bytes, 2B messages a day, about 60G storage.
- Service: message service information management, responsible for the basic transmission and storage of information; RealTime service, mainly responsible for information reading operations.
- storage:
For a chat software, the storage of information is the key. The normal idea is to only keep in the table, from_user_id sender id, to_user_id receiver id, content content, created_time creation time. But this design has obvious shortcomings. For example, when we query the conversation between two people, we need
SELECT * FROM message_table WHERE from_user_id=A and to_user_id=B OR to_user_id=B and from_user_id=A ORDER BY created_at DESC;
This query is obviously very inefficient, and if it is a multi-group chat, this method is difficult. For applications such as WeChat, any interaction is two-way between receiving and sending, so it is a better idea to define a dialog, introduce sessionId, and identify each dialog. We can design a Message table. This table is for the storage of messages for all users of the entire app. In addition, there is a Thread table for everyone. The two tables are connected by thread id. The advantage of this design is that we can easily query all the user's speech information for the message table. For the user to retrieve the information of a certain dialogue, the parameter Thread id must be specified, so we can easily query the information of a certain dialogue when we inquire. And for the user's dialog settings, it actually includes a lot of private settings, such as chat notes and mute settings. In other words, the information sent by all users is a common table, and the conversations of all users are another table.
For the message table sub-table key, thread id is best. As we mentioned earlier, the conversation id is usually specified every time a query is made. This can be used as a sub-table (the setting of the sub-table key must be considered from the business side. When most queries are made, which parameters we will carry, this parameter is suitable as the sub-table key). For thread table, owner_id is more suitable as a sub-table key, because this is generally provided to users, and users only need to query "what conversations do I have". The primary key of this table should be [owner_id, thread_id], it may be better to index this. At the same time, we also need to index the Owner ID+update time, because what we generally provide to users is sorted by update time.
For the message table, the amount of data is relatively large and simple, and there is no need to increase the id. Each message is a log. You can use persistent nosql, use thread id as the key, and the value can be {user_id, content, created_time} json. For the Thread table, because the index needs to be used and the search and filtering are often performed, it is better to use sql.
The flow of users sending and receiving messages
- The user sends a message message service:
First, the client sends the message and the message receiver to the server, here is a conversation for 1vs1. If it is a multi-person chat, it will generally retrieve whether there is a corresponding session id in the machine now, if it exists, send the session id directly to the server, otherwise entrust the server to establish one (let the server query whether there is a session among multiple people ID is very troublesome. It is necessary to also index the participants in the thread table, which is more troublesome). Then the server creates a message, which contains {user_id, content, created_time}. There are some clever optimizations here. ThreadId can have some tricks when it is created. For example, for a conversation between two people, we can define the ID to be a combination of the IDs of two people, so that it is easier to find. The group chat ID can be creator + creation time, etc.
- User acceptance information RealTime service:
The simpler method is to ask the server to check if there is any information in 5s. This is the simplest, but there is a significant delay. The concept of socket can be introduced here, and the server provides push service, which can maintain a long connection with the client. When the user opens the app, he connects to his own socket in the push service. When someone sends a message, the message service receives the message and sends it out through the push service. If a user does not open the app for a long time, he can cut off the connection and release the port. Both Android GCM and ios APNS can be maintained. The core difference between socket and http is that HTTP can only request data from the server from the client, but the server can actively push data to the client under the socket . From the perspective of architecture, it is possible to separate the two modules of information sending and information pushing.
- Group chat between users
The number of group chats is very large, and each message has to be sent to many people. But many users are actually offline, only the push service module knows whether the user is online. Therefore, we add a layer in the middle, channel service. For larger group chats, online users need to subscribe to the corresponding group chat channel first. When a user goes online, find the group chat to which the user belongs and mark it. The channel knows which channels the user is still alive. When the user goes offline, the push service notifies the channel. Therefore, when sending a message, the message is sent to the channel, and the channel pushes online users. This part uses memory storage, and restarts when it hangs up.
- Inquiry of user online status The
server needs to know which users are online at each moment; the user also needs to know which friends are online. It can also be divided into two ideas, push and pull.
Push is when the user tells the server to go online and offline. But the disadvantage of this is that after a sudden network error, the user cannot tell the server. The server tells all users at regular intervals which of their friends are online.
The pull method is better. The heartbeat strategy is still adopted. After the user goes online, a heartbeat is sent to the service every few seconds to tell the server to survive. Every time an online friend requests the server to check the online status of his friend. Therefore, this method is also easy to know how long the user has been offline.
System design-how to limit current
The current limit often appears in the program, limiting the number of times to refresh the webpage in a short period of time, etc. For general business, current limit can be achieved by simply maintaining the database. But for the spike business, the database method is very efficient, and we need to design a better strategy. First of all, from the perspective of engineering implementation, Google has the open source RateLimiter tool, which uses the token bucket algorithm, which can effectively limit the input traffic. Of course, this module can actually be considered as a small system design problem, and we can also use the 4S method for analysis.
- Scenario: Limit the user's behavior, such as limiting the behavior within the last 30s, and limit the behavior if the number exceeds this amount.
- Service: It is already the smallest module in itself and cannot be further refined.
- Storage: This part of the data can be used to analyze website traffic, etc. And it does not require very strong consistency and accuracy, but the rate of reading and writing is very high. Therefore, the efficient access structure of redis can be used.
Design ideas:
- The first is a relatively simple design method, we use the redis key expiration strategy. For example, if we require that an operation cannot exceed 10 operations in one minute, then I will use the minute of the current system time as the key and set the expiration time to 2 minutes to ensure that the number of times within this minute is fully calculated. This method is relatively simple. What granularity we need is limited by what granularity is used as the key. But it is not completely accurate. For example, we can think that in the most extreme case, there may be twice the traffic in the net time. However, the requirements for current limiting are generally not required to be accurate.
- Another strategy is to use the most fine-grained time as the key, such as the second level, the expiration time is the minute level, and then when the minute traffic is counted, the cumulative sum can be looped. In this way, the traffic in the last minute can be obtained very accurately. The idea is similar to constantly writing a looping array. Generally speaking, we want to count the minute-level traffic, then our key is the second-level, and the expiration time is the minute-level. If it is day level, the key is the hour level, and the expiration time is the day level. This can ensure that the number of loops will not be too many when querying.
Of course, this will bring some errors. If you still need to get it accurately, we can use a multi-level query strategy. For example, we want to get the number of visits in the most recent day. The current time is 23:30:33, and the sum includes the second level 23:30:00 ~ 23:30: 33 a total of 34 queries, in the sub-query 23: 00 ~ 23: 29 a total of 30 queries, the current query 00 ~ 22, a total of 23 times. In addition, yesterday’s 26 seconds and 29 minutes, a total of 42 queries.
Google's Ratelimiter source code
The token bucket design idea is adopted, which can limit the number of submitted threads and limit the amount of data to be executed. The most distinctive feature is the delayed waiting strategy, which means that the number of requested licenses does not affect the control of the request itself. For example, if 100 tokens are currently requested, the system will also release them, but subsequent requests will compensate for the waiting.
Explain RateLimiter in detail
System design-datadog, website visit data statistics
Need to count website traffic, which can be used as system analysis data. For visits to a certain webpage, each visit is incremented by one, and we need to know the last counted times.
- Storage: This is a counting problem, which means that the system is almost all writes and almost no reads. And we need to be persistent. And the function should be very simple, we can use the "name + timestamp" of the operation as the key, and +1 for each access; but it should be noted that the granularity of the storage is. For the most recent week’s data, we may need the minute level, this month’s need ten minutes level, this year’s need hour level, last year’s data may be based on the day. Therefore, we can learn from the idea of multi-bucket, and organize and summarize each time. Reorganize regularly.
Taking into account the detection every time, if you need to monitor a lot of business, one update per second is very large qps, so you can entrust the server to cache the data every 15s, and then focus on the datadog feedback. At the same time, it is necessary to periodically Retention the data to lose weight.
System design-web crawler system
The crawler system can help companies collect information, and will use knowledge such as multithreading and system design. The crawler can obtain the corresponding text information by crawling the source code of the webpage of the website url address. For crawler systems, all web pages need to be crawled regularly for updates, and more storage space is required.
- Scenario: One trillion webpages, 160w webpages per second. It needs to be updated once a week. The storage space is 10K per web page, and it takes about 10 petabytes to save it.
- service: Including crawling system, taskservice, storageservice
- Storage: DB storage can be used for crawling tasks, but the crawled data may only be stored using BigTable.
Implementation
We directly consider the multi-threaded design. First, we give multiple starting portals as the starting point, and then when the crawler goes to this url to crawl, it reads the source code of the web page, and then can use regular expressions to complete the response Crawling of specific content. For example, we want to crawl a certain
Tags surrounded by
<h3[^>]*><a[^>]*>(.*?)<\/a><\/h3>memory . In order to use multithreading, the search method of bfs is more convenient. But here we can’t use queue to allocate tasks, because the queue is stored in memory, but because there are too many URLs, it cannot be loaded into memory; and the URL queue is not very good to control the priority of grabbing, etc. Some news pages may be crawled more frequently. Therefore, we can use db to store a task table so that we can crawl more customized.
Upgrade strategy
- How to control the crawl frequency? It can be compared each time it is crawled. If the content of the web page changes, the crawling frequency will be doubled. If nothing changes, you can reduce the frequency. Thereby dynamically adjusting the update frequency.
- How to solve the problem of crawling dead links? The content of the portal may be internally redirected, and we need to have a limit, for example, the current limit of qq.com requires 10%.
- Reptiles are distributed in many regions. For American websites, crawl from the United States, and for Chinese websites from China.
System design-spelling association
When we type, type, or search engines, we often have the association function. In fact, this is a topK query with a specific prefix.
- Scenario: An application with a DAU of 500m, the search volume per day can be considered to be used 6 times, each time about 4 characters. So the qps is about 4 * 6 * 500m / 86400 = 138K. The peak value is expected to be about 2 to 3 times.
- Services: query services, data collection services. The query service is based on the current prefix of the user to obtain topK. Data collection needs to consider the most recent query hot words, and then sort and store them.
- Storage: For query services, we must be in memory, and the cache can be used to speed up the more efficient. Then the general data can be in the form of a dictionary tree. The storage of complete data must be stored in the hard disk through log data.
Using the dictionary tree, it is easy to find what the current high-frequency words are. This is a way of thinking about space-for-time. Of course, this structure is stored in the content, and it can be considered that this part should be allocated to the query service. Finally, it is put into the hard disk through serialization.
The user's search records are recorded in the form of log, which can be sorted regularly using dataCollectionService. For example, it is updated every hour, and then the data is reintegrated into a new trie tree, and then hot-switched.
- expand
- Performance evaluation: After entering the prefix, the time to give the recommended word can be used as an indicator; the hit rate is also an indicator.
- How to improve the response time? First, you can use the browser for caching, and secondly, there is a pre-fetch idea. For example, when I input ab, I search for the top10 of ab and the top10 of these words, which is 100 data. So progressive, so that we greatly increase the speed of response.
- How to deal with the situation that tire is too large. We can use the consistent hashing method. For example, when we have multiple queryService machines, when inputting a, the consistent hash points to machine 1 for searching and returning the answer. Then when you enter ab, go to machine 2 to search again.
- The log file takes up too much space? You can use the probability method to compress the log. Whenever someone queries amazon, I will do a randomization from 1-1000. Therefore, we can understand that we have used this probability method for recording. The premise of this is that you only want to query a large amount of data.
Distributed File System (GFS)
Google Three Musketeers, GFS (google file system) file system, Map Reduce quickly process data, how Bigtable connects the underlying storage and the upper data.
The commonly used distributed file system is HDFS, which is an open source distributed file system. But it mainly comes from the evolution of GFS.
- Scenario: The user needs to write and read files. The files that support writing can be very large. At the same time, we need to be able to use multiple machines to store these files, so we need to consider the collaboration between machines.
- Service: It is a client+server model, and our client needs to split files and so on. The server needs to complete the storage. At the same time, how to store is involved here.
Commonly used models include the peer2peer model , which has no central node, which makes it difficult to cause consistent synchronization. The advantage is that there is no bottleneck, and the node can continue to work if it is hung up. The difficulty is synchronization consistency.
The Master-slave model has a central node, and the others are slaves. The master node is only responsible for control and does not perform any storage operations; the storage operations are all handled by the child nodes, which is very similar to the sentinel mode. The advantage is that it is easy to maintain data consistency, but the disadvantage is that the master node has become a performance bottleneck. If the master hangs, restart it immediately.
- Storage: Large files are stored in the file system. Data is generally stored in relatively small information files. For very large files, slicing may be required, and it is best to put them in a dedicated file system.
A large file may include basic file information such as metadata-file name, creation and modification time, size, and the specific content of the file. It is best to store the two separately, the metadata file can be loaded directly into the memory, so this part of the file is relatively small and often accessed. The theme of the file is stored in the hard disk. For windows, continuous storage is used, and Linux uses a better separate storage.
The advantage of separate storage is that it can solve the problem of space fragmentation. Large files are divided into small chunks, each of which is about 64M in size. The advantage is that the size of the metadata file can be reduced, because the relative position of all chunks needs to be stored in the metadata, and the disadvantage will be a little fragmented. After using the master-slave model, the real data is stored in the salve, and the master only stores the metadata, which will indicate where each chunk is stored. And the offset does not need to be stored in the metadata, it can be stored in the corresponding chunk.
The metadata of a 64M file is probably only 64B, so for a very large file, the metadata can actually be read into the memory.
Write : It is written by splitting, and the splitting process is completed on the client. This ensures that the cost of error retransmission during transmission is also relatively small. In the writing process, the client first interacts with the master, and then the master can tell the client that it should be stored on the slave according to the idle condition of the disk and the busy condition of the node. The client is in contact with the slave.
Modification : GFS itself does not support the modification of the file. If the modification is really done, it is in fact to write a new copy in a new space.
Reading : The client interacts with the master, the master tells the client where to read the fragment from, and then the client reads in the slave.
That is, the task of the master includes: storing the metadata of all files, storing a map (file name + chunk index -> chunk server), and assigning it during reading and writing.
- expand:
Q: Is single master a bottleneck: Single master is a strategy used by 90% of the industry because of its simpler design. If necessary, you can also upgrade to multiple masters, paxos algorithm to coordinate multiple masters
Q: How to perform verification? Use checksums, simply include MD5, etc. Add a checksum to the end of each chunk. The checksum is very small, 4bytes=32bit, for a 1P file, it is 1P/64MB*32bit=62.5MB. Check the checksum when reading this file. If it is inconsistent, you can correct it from other backup points.
Q: How to detect whether a slave node is working normally? The slave node periodically performs a heartbeat detection mechanism.
Q: How to back up the writing process first? A better method is that the client only writes to one slave node during each transmission, and then this slave node becomes a team leader node, responsible for synchronizing other nodes. This idea is very similar to the design idea of sentry + cluster. The selection of the team leader node can be the nearest geographically or idle. The team leader here may not be fixed, and there can be a different team leader according to each client request.
Real question
Q: Design a read-only lookup service. The data in the background is 10 billion key-value pairs, and the service format is to accept the key input by the user and return the corresponding value. It is known that the size of each key is 0.1kB, and the size of each value is 1kB. Requires system qps >= 5000, latency <200ms.
Server parameters: commodity server, 8X CPU cores on each server, 32G memory, 6T disk . Use any number of servers to design this service.
A:
total key size ~ 10 billion * 0.1kB = 1T;
total value size ~ 10 billion * 1kB = 10T.
So each server uses two hard drives, a total of 12T. The data structure uses SSTable (Sorted String Table).
To make full use of memory, I originally wanted to use a binary search tree as an index, but I think about it carefully that this service is read-only, and the hard disk stores the key-value pairs using SSTable, which is ordered, and the key and value lengths are fixed, so Just store the keys in the memory in an orderly manner. When querying, perform a binary search on the keys, and then use the offset of the key in the memory to calculate the offset of the key-value pair in the hard disk. 1T/32G = 31.25. So a total of 32 servers are required to share the key index. Add a master in front to manage consistent hasing. lg(32G) = 35, the average query for a key is 18 memory accesses, which is only about 1800ns, which can be ignored on the order of ms.
For each request, the time to read 1kB value on the hard disk: 10ms(disk seek) + 4ms(rotation delay for 7200rpm) + 1kB/1MB * 30ms(reading 1kB sequentially from disk) = 14ms. Currently a server can handle QPS: 1000ms/14ms = 71, total QPS: 71 * 32 = 2272. There is still more than twice the gap from the requirements. So we can install 6 6T hard disks for each server to form 3 sets of data hard disks. The 3 sets of hard disks can process 3 requests in parallel, which can be regarded as slightly using the 8X multi-core CPU. At this time, QPS is 2272 * 3=6816.
delay:
- Master memory search time for consistent hashing map: Ignore
- The round trip delay of master and slave: 1 round trip in the same data-center is 1ms.
- Slave memory index query time: Ignore
- Slave hard disk read time: 14ms
so total latency is 15ms.
Map Reduce (counting in big data scenarios)
Map reduce, GFS, the three carriages of Google's big data.
Background of the problem: Count the frequency of words in all websites. If a single machine performs statistics, there is a performance bottleneck, so the big data processing method is selected. Multiple machines are responsible for the two processes of map and reduce. The map is responsible for counting the number of words in an article, and the reduce is responsible for merging the number of specific words.
The whole process can be divided into six processes. Input sets the input file, split system completes the average distribution of files to the machine, map implements article segmentation into words , transfers and organizes, reduce implements word unity , and output sets output files. The big data framework has helped us complete the basic construction, we only need to implement map and reduce. Pay attention to the input and output of the two functions. Map input: key article storage address, value article content. Reduce input: key, key output by map, value: value output by map.
/** * Definition of OutputCollector: * class OutputCollector<K, V> { * public void collect(K key, V value); * // Adds a key/value pair to the output buffer * } */ public class WordCount { public static class Map { public void map(String key, String value, OutputCollector<String, Integer> output) { // key 对应这个文章的地址 // value 对应文章的内容 String[] tokens = value.split(" "); for(String word:tokens){ output.collect(word,1); } // Output the results into output buffer. // Ps. output.collect(String key, int value); } } public static class Reduce { public void reduce(String key, Iterator<Integer> values, OutputCollector<String, Integer> output) { int sum = 0; while(values.hasNext()){ sum += values.next(); } output.collect(key,sum); // Output the results into output buffer. // Ps. output.collect(String key, int value); } } }
The number of machines for map and reduce is up to you. But it is not necessarily the more machines, the better, the increase of machines can increase the parallel speed of data processing, but the cost of starting the machine needs to be considered, and there is an upper limit for reduce (the type of words), blindly increasing the machine will lead to the master The pressure has also increased.
When the word frequency is counted, there is a stopwords list. The content of this list needs to be filtered for some high-frequency meaningless words, including I, you, the, etc. When these words are counted, skip directly.
The sorting here can only use outer sorting, because the amount of data is very large, so it cannot be loaded into memory and sorted directly. The basic idea of external sorting is to first split the large files into the memory and read them normally, then sort the small files in the memory, and then use the K-way merge strategy to merge.
Typical topic
- Inverted list: Count in which articles a certain word appears. Here we need to count which words (map) appear in each article, and then distribute (reduce) statistics according to the words and finally output an inverted list.
- Similar words: Split a large number of words, and then count which words appear in a certain sort.
System Design of Map Reduce
Both input files and output files need to be placed on GFS. The intermediate process volume only needs to be placed on the local hard disk without special processing.
- Q: What is the working order of mapper and reducer? The mapper needs to complete the work before the reducer can start working.
- Q: What should I do if the mapper or reducer hangs during operation? When we start again, there is actually a machine pool, and then the master controls and controls the machines to perform different tasks. If it hangs, it will reassign a machine for execution.
- Q: What problems can be caused by the fact that the statistical value of a key is very large? How to solve it? It will lead to imbalance, and the running time of a reducer is very long. You can add a random number after the key, which is equivalent to dividing the key into several blocks.
Distributed database Bigtable
Solve Nosql database problems in big data scenarios. The file system generally gives an address and then returns a file. The database system obtains certain data from files (tables) filled in according to certain specifications. The core is to query data. Under normal circumstances, the database system is established on the file system, responsible for organizing and storing some data in the file system, and the external interface is more convenient to manipulate the data.
- Scenario (requirement): Query a key and be able to return the corresponding value. The scene is relatively simple. The data is not stored in the form of a table, but may be written in json format, etc., and then serialized and stored in a file.
How to search from the files on the hard disk? Due to the huge amount of data, it is impossible to read all of it into the memory for searching. A feasible idea is to save the data to the hard disk in an orderly manner, and then divide the files on each hard disk into two. Here, the idea of partial sorting is designed. The idea of hard disk dichotomy is also to partially read in and then search.
How to solve the data modification problem? It is not possible to modify directly from the file, because the file size after modification cannot be guaranteed; it is also inappropriate to read the entire file for copying, and the efficiency is too low. The feasible approach is to directly append at the end of the file. But this will cause some new problems. First of all, because this part of the data is modified later, it must be disordered, and there will be multiple data, it is not easy to find the correct data. Only after a period of time, the files can be organized in an orderly manner. For example, each time we put the added information in the memory, after reaching a certain size, it will be sorted in the memory once, and then written to the hard disk for persistence. The advantage of this is that each file is a small block, ensuring that the data is in order within each block, and only the last added information is out of order in the memory. Therefore, when we are looking for data, for loops each hard disk and then divides the hard disk into two. For the modified data, we can add a timestamp to ensure that the data obtained is the latest data. Since this may result in the storage of some redundant information, we can perform K-way merging and sorting data every once in a while.
Read and write process of the complete system
During the data writing process, the starting cheap address of each file block is stored in the memory. The writing process is first performed in the memory, where the data structure of the jump table is used , and then serialized to the hard disk. Ensure that the hard drives are in order. In order to ensure that in case of memory power failure, data loss, we need to additionally adopt WAL strategy. Of course, wal needs to write to the hard disk, but this is very fast. Therefore, the writing process requires memory sorting + one hard disk uniform write + one hard disk log write.
In the process of data reading, first go to the memory to read, if it is read, it will directly return to the latest; otherwise, it will go to each hard disk file for dichotomy. In order to speed up the indexing we can build, each file will be indexed by itself. Because each file is internally ordered, but the files may not be in order, the index is stored in the memory (if it is too large, it can be placed on the hard disk and read in batches). The index can be used quickly Positioning should go to a certain position of a file block to read. Sstable = Sorted String Table
How to quickly check whether a certain data is in the file? If a file is not in the file, there is no need to read it. It is possible to use a hashmap, but for a large amount of data, it will take up more space. It is better to use the bloom filter. The bloom filter is Multiple hash functions are composed of bit arrays. For a key, each hash function is hashed to get the corresponding value, and the corresponding position is set in the bit array. In this way, when we judge, we can judge whether the corresponding positions are all 1s. Therefore, you can see the characteristics of the Bloom filter, he said that there must be no, and that some may be misjudged. The probability of misjudgment is related to the number of hash functions, the length of the bit array, and the number of strings added.
Clustered Bigtable+GFS
How to implement clustering? It is also necessary to have a master to perform control operations such as consistent hashing. Where the master directs the client to read and write data. If the amount of data continues to increase and the stand-alone hard disk cannot be written or opened, GFS can be used in combination. Split bigtable's sstable into small chunks and write them into GFS.
We generally turn Bigtable's salve into a Tablet server, which is actually the slave server of the stored tablet. For bigtable, we need to consider competition issues because of modification operations, so we need to introduce distributed locks. Such as chubby used by Google or zookeeper used by hadoop. When the user reads, the request will be sent to lock. After the lock performs consistent hashing, the corresponding node will be locked, and then the node information will be returned to the client for reading and writing. After completion, the lock resource will be released. In other words, lock has taken over part of the original master's services. The main task of the master now is to detect the health of the slave and perform sharding at startup. The rest of the metadata can be handed over to the lock operation.
Therefore, the entire system requires Client + Master + Tablet Server + Distributed Lock. Among them, distributed locks need to update metadata (index information, etc.), and lock and unlock the key.
In the whole design idea, in order to speed up writing, we adopt additive writing and use sstable; in order to speed up reading: hard disk is divided into two, metadata maintains index and bloom filter. | https://ideras.com/system-design-from-service-to-architecture/ | CC-MAIN-2021-25 | refinedweb | 10,005 | 62.38 |
JVM in the uWSGI server (updated to 1.9)¶
Introduction¶
As of uWSGI 1.9, you can have a full, thread-safe and versatile JVM embedded in the core. All of the plugins can call JVM functions (written in Java, JRuby, Jython, Clojure, whatever new fancy language the JVM can run) via the RPC subsystem or using uWSGI The uWSGI Signal Framework The JVM plugin itself can implement request handlers to host JVM-based web applications. Currently The JWSGI interface and The Clojure/Ring JVM request handler (Clojure) apps are supported. A long-term goal is supporting servlets, but it will require heavy sponsorship and funding (feel free to ask for more information about the project at info@unbit.it).
Building the JVM support¶
First of all, be sure to have a full JDK distribution installed. The uWSGI build system will try to detect common JDK setups (Debian, Ubuntu, Centos, OSX...), but if it is not able to find a JDK installation it will need some information from the user (see below). To build the JVM plugin simply run:
python uwsgiconfig.py --plugin plugins/jvm default
Change ‘default’, if needed, to your alternative build profile. For example if you have a Perl/PSGI monolithic build just run
python uwsgiconfig.py --plugin plugins/jvm psgi
or for a fully-modular build
python uwsgiconfig.py --plugin plugins/jvm core
If all goes well the jvm_plugin will be built. If the build system cannot find a JDK installation you will ned to specify the path of the headers directory (the directory containing the jni.h file) and the lib directory (the directory containing libjvm.so). As an example, if jni.h is in /opt/java/includes and libjvm.so is in /opt/java/lib/jvm/i386, run the build system in that way:
UWSGICONFIG_JVM_INCPATH=/opt/java/includes UWSGICONFIG_JVM_LIBPATH=/opt/java/lib/jvm/i386 python uwsgiconfig --plugin plugins/jvm
After a successful build, you will get the path of the uwsgi.jar file. That jarball containes classes to access the uWSGI API, and you should copy it into your CLASSPATH or at the very least manually load it from uWSGI’s configuration.
Exposing functions via the RPC subsystem¶
In this example we will export a “hello” Java function (returning a string) and we will call it from a Python WSGI application. This is our base configuration (we assume a modular build).
[uwsgi] plugins = python,jvm http = :9090 wsgi-file = myapp.py jvm-classpath = /opt/uwsgi/lib/uwsgi.jar
The jvm-classpath is an option exported by the JVM plugin that allows you to add directories or jarfiles to your classpath. You can specify as many jvm-classpath options you need. Here we are manually adding uwsgi.jar as we did not copy it into our CLASSPATH. This is our WSGI example script.
import uwsgi def application(environ, start_response): start_response('200 OK', [('Content-Type','text/html')]) yield "<h1>" yield uwsgi.call('hello') yield "</h1>"
Here we use uwsgi.call() instead of uwsgi.rpc() as a shortcut (little performance gain in options parsing). We now create our Foobar.java class. Its static void main() function will be run by uWSGI on startup.
public class Foobar { static void main() { // create an anonymous function uwsgi.RpcFunction rpc_func = new uwsgi.RpcFunction() { public String function(String... args) { return "Hello World"; } }; // register it in the uWSGI RPC subsystem uwsgi.register_rpc("hello", rpc_func); } }
The uwsgi.RpcFunction interface allows you to easily write uWSGI-compliant RPC functions. Now compile the Foobar.java file:
javac Foobar.java
(eventually fix the classpath or pass the uwsgi.jar path with the -cp option) You now have a Foobar.class that can be loaded by uWSGI. Let’s complete the configuration...
[uwsgi] plugins = python,jvm http = :9090 wsgi-file = myapp.py jvm-classpath = /opt/uwsgi/lib/uwsgi.jar jvm-main-class = Foobar
The last option (jvm-main-class) will load a java class and will execute its main() method. We can now visit localhost:9090 and we should see the Hello World message.
Registering signal handlers¶
In the same way as the RPC subsystem you can register signal handlers. You will be able to call Java functions on time events, file modifications, cron... Our Sigbar.java:
public class Sigbar { static void main() { // create an anonymous function uwsgi.SignalHandler sh = new uwsgi.SignalHandler() { public void function(int signum) { System.out.println("Hi, i am the signal " + signum); } }; // register it in the uWSGI signal subsystem uwsgi.register_signal(17, "", sh); } }
uwsgi.SignalHandler is the interface for signal handlers.
Whenever signal 17 is rased, the corresponding JVM function will be run. Remember to compile the file, load it in uWSGI and to enable to master process (without it the signal subsystem will not work).
The fork() problem and multithreading¶
The JVM is not fork() friendly. If you load a virtual machine in the master and then you fork() (like generally you do in other languages) the children JVM will be broken (this is mainly because threads required by the JVM are not inherited). For that reason a JVM for each worker, mule and spooler is spawned. Fortunately enough, differently from the vast majority of other platforms, the JVM has truly powerful multithreading support. uWSGI supports it, so if you want to run one of the request handlers (JWSGI, Clojure/Ring) just remember to spawn a number of threads with the --threads option.
How does it work?¶
uWSGI embeds the JVM using the JNI interface. Unfortunately we cannot rely on JVM’s automatic garbage collector, so we have to manually unreference all of the allocated objects. This is not a problem from a performance and usage point of view, but makes the development of plugins a bit more difficult compared to other JNI-based products. Fortunately the current API simplifies that task.
Passing options to the JVM¶
You can pass specific options to the JVM using the --jvm-opt option.
For example to limit heap usage to 10 megabytes:
[uwsgi] ... jvm-opt = -Xmx10m
We have already seen how to load classes and run their main() method on startup. Often you will want to load classes only to add them to the JVM (allowing access to external modules needing them) To load a class you can use --jvm-class.
[uwsgi] ... jvm-class = Foobar jvm-class = org/unbit/Unbit
Remember class names must use the ‘/’ format instead of dots! This rule applies to --jvm-main-class too.
Request handlers¶
Although the Java(TM) world has its J2EE environment for deploying web applications, you may want to follow a different approach. The uWSGI project implements lot of features that are not part of J2EE (and does not implement lot of features that are a strong part of J2EE), so you may find its approach more suited for your setup (or taste, or skills).
The JVM plugin exports an API to allow hooking web requests. This approach differs a bit from “classic” way uWSGI works. The JVM plugin registers itself as a handler for modifier1==8, but will look at the modifier2 value to know which of its request handlers has to manage it. For example the The Clojure/Ring JVM request handler plugin registers itself in the JVM plugin as the modifier2 number ‘1’. So to pass requests to it you need something like that:
[uwsgi] http = :9090 http-modifier1 = 8 http-modifier2 = 1
or with nginx:
location / { include uwsgi_params; uwsgi_modifier1 8; uwsgi_modifier2 1; uwsgi_pass /tmp/uwsgi.socket; }
Currently there are 2 JVM request handlers available:
- The JWSGI interface
- The Clojure/Ring JVM request handler (for Clojure)
As already said, the idea of developing a servlet request handler is there, but it will require a sponsorship (aka. money) as it’ll be a really big effort.
Notes¶
- You do not need special jar files to use UNIX sockets – the JVM plugin has access to all of the uWSGI features.
- You may be addicted to the log4j module. There is nothing wrong with it, but do take a look at uWSGI’s logging capabilities (less resources needed, less configuration, and more NoEnterprise)
- The uWSGI API access is still incomplete (will be updated after 1.9)
- The JVM does not play well in environments with limited address space. Avoid using --limit-as if you load the JVM in your instances. | http://uwsgi-docs.readthedocs.org/en/latest/JVM.html | CC-MAIN-2014-52 | refinedweb | 1,373 | 57.47 |
derwin, newwin, subwin - window creation functions
#include <curses.h> WINDOW *derwin(WINDOW *orig, int nlines, int ncols, int begin_y, int begin_x); WINDOW *newwin(int nlines, int ncols, int begin_y, int begin_x); WINDOW *subwin(WINDOW *orig, int nlines, int ncols, int begin_y, int begin_x);
The derwin() function is the same as subwin(), except that begin_y and begin_x are relative to the origin of the window orig rather than absolute screen positions.
The newwin() function creates a new window with nlines lines and ncols columns, positioned so that the origin is (begin_y, begin_x). If nlines is zero, it defaults to LINES - begin_y; if ncols is zero, it defaults to COLS - begin_x.
The subwin() function creates a new window with nlines lines and ncols columns, positioned so that the origin is at (begin_y, begin_x). (This position is an absolute screen position, not a position relative to the window orig.) If any part of the new window is outside orig, the function fails and the window is not created.
Upon successful completion, these functions return a pointer to the new window. Otherwise, they return a null pointer.
No errors are defined.
Before performing the first refresh of a subwindow, portable applications should call touchwin() or touchline() on the parent window.
Each window maintains internal descriptions of the screen image and status. The screen image is shared among all windows in the window hierarchy. Refresh operations rely on information on what has changed within a window, which is private to each window. Refreshing a window, when updates were made to a different window, may fail to perform needed updates because the windows do not share this information.
A new full-screen window is created by calling:
newwin(0, 0, 0, 0);
delwin(), is_linetouched(), doupdate(), <curses.h>. | http://pubs.opengroup.org/onlinepubs/7990989799/xcurses/derwin.html | crawl-003 | refinedweb | 291 | 53.41 |
Head First Java (2nd Ed.) p. 112
marsooka
Greenhorn
Joined: Dec 31, 2006
Posts: 3
posted
Dec 31, 2006 10:43:00
0
The instructions on page 112 are to "Drop all three classes(...) into the same directory...
my question is based on the fact that the only successful class/java-file i compiled was the one called GameHelper. What is the exact syntax and file name(s) of the other two supposed to be, i've tried many and continue to get compile errors...
the other two (saved in one .java file together, or two separate .java files) are referred to as SimpleDotCom and SimpleDotComGame.
thanks, marsooka
[ December 31, 2006: Message edited by: barclay mcdaniel ]
Bert Bates
author
Sheriff
Joined: Oct 14, 2002
Posts: 8898
5
posted
Dec 31, 2006 11:59:00
0
Hey Barclay,
Can you tell us a little more about exactly what files you have (their exact names), what directory(ies) they are in, what compiler command you're using, and exactly what errors you're getting?
Thanks!
Bert
Spot false dilemmas now, ask me how!
(If you're not on the edge, you're taking up too much room.)
Davy Kelly
Ranch Hand
Joined: Jan 12, 2004
Posts: 384
posted
Dec 31, 2006 13:11:00
0
i think what they are trying to say is that the 3 classes should be in the same directory e.g. C:\Program Files\Java\jdk1.5.0_03 so that you can compile and run them you only compile the SimpleDotComTestDrive file and the rest should compile automatically
then run it.
so to re-iterate, have all 3
java
files in a directory typically, where the bin file is.
save all 3 files with their Class_Name.java, here is the code:
public class SimpleDotComTestDrive { public static void main(String[] args) { int numOfGuesses = 0; //variable to track how many guesses a user makes GameHelper helper = new GameHelper(); //this is a special class that has the method for getting user input (made up class) SimpleDotCom theDotCom = new SimpleDotCom(); //instantiate a simple DotCom object int randomNum = (int)(Math.random() * 5); //a random number for the first cell of the locations array int[] locations = {randomNum, randomNum+1, randomNum+2}; //make an int array for the location of the DotCom (3 cnosecutive out of 7) theDotCom.setLocationCells(locations); //invoke the setter method on the DotCom boolean isAlive = true; //a boolean to track whether the game is still alive, to use in the while loop while (isAlive == true) { String guess = helper.getUserInput("enter a number"); String result = theDotCom.checkYourself(guess); //invoke the check method on the DotCom object and pass it the fake guess numOfGuesses++; //increment post count if (result.equals("kill")) //if it is a kill set boolean to false { isAlive = false; System.out.println("You took "+numOfGuesses+ " guesses"); } //end if } //end while } //end main method } //end class
class SimpleDotCom { int[] locationCells; int numOfHits = 0; public void setLocationCells(int[] locs) { locationCells = locs; } public String checkYourself(String stringGuess) { int guess = Integer.parseInt(stringGuess); //converting the string guess to an int String result = "miss"; //a variable to hold the result, miss is default for (int cell: locationCells)//repeat with each cell in the locationCells array (each cell location of the object) { if (guess == cell) //compare the user guess to this element (cell) in the array { result = "hit"; numOfHits++; //increment numOfHits by one break; //break out of the for loop }//end if }//end for loop if (numOfHits == locationCells.length) //we are out of the loop but is the object been hit 3 times succesfully { result = "kill"; }//end if System.out.println(result); //display the result for the user return result; // return the result back to the calling method }//end checkYourself method }
import java.io.*; import java.util.*; public class GameHelper { private static final String alphabet= "abcdefg"; private int gridLength = 7; private int gridSize = 49; private int[] grid = new int[gridSize]; private int comCount =("IOException: "+e); } return inputLine.toLowerCase(); } public ArrayList<String> placeDotCom(int comSize) { ArrayList<String> alphaCells = new ArrayList<String>(); String[] alphacoords = new String[comSize]; //holds "f4" type coords String temp = null; //tekp string for concat int[] coords = new int[comSize]; //current candidate coords int attempts = 0; //current attempt counter boolean success = false; //flag = found a good location int location = 0; //current starting location comCount++; //nth dot com to place int incr = 1; //set horizontal increment if ((comCount % 2) == 1) //if odd dot com (place vertically) { incr = gridLength; //set vertical increment } while (!success & attempts++ < 200) //main search lpp[ (32) { location = (int)(Math.random()*gridSize); //get random starting point //System.out.print("try "+location); //cheat int x = 0; //nth position in the dot com to place success = true; //assume success while (success && x < comSize) //look for adjacent unused spots { if (grid[location] == 0) //if not already used { coords[x++] = location; //save location location += incr; //try next adjacent if (location >= gridSize) //out of bounds - bottom { success = false; //failure } //end if if (x > 0 && (location % gridLength == 0)) //out of bounds right edge { success = false; //failure }//end if } else //found already used location { //System.out.print(" used "+location); //cheat success = false; //failure }//end outer if/ else }//end inner while }//end outer while int x = 0; //turn location into alpha coords int row = 0; int column = 0; //System.out.println("\n"); //make a new line while (x < comSize) { grid[coords[x]] = 1; //mark master grid pts. as 'used' row = (int)(coords[x] / gridLength); //get row value column = coords[x] % gridLength; //get numeric column value temp = String.valueOf(alphabet.charAt(column)); //convert to alpha alphaCells.add(temp.concat(Integer.toString(row))); x++; //System.out.prit(" coord "+x+" = " +alphaCells.get(x=1)); //this is exactly where the dot com is located } //System.out.println("\n"); //new line return alphaCells; } }
compile "javac SimpleDotComTestDrive.java" this will in turn compile the rest, then run it java SimpleDotComTestDrive this should run all 3 classes as the game.
davy
[ December 31, 2006: Message edited by: Davy Kelly ]
How simple does it have to be???
Jeanne Boyarsky
author & internet detective
Marshal
Joined: May 26, 2003
Posts: 32016
200
I like...
posted
Dec 31, 2006 13:33:00
0
Barclay,
Yes, each (public) class should be in a separate file. When you compile them, be sure to compile in one step so all the classes are found.
>javac *.java
[
marsooka
Greenhorn
Joined: Dec 31, 2006
Posts: 3
posted
Dec 31, 2006 14:05:00
0
thanks...
[ December 31, 2006: Message edited by: barclay mcdaniel ]
I agree. Here's the link:
subject: Head First Java (2nd Ed.) p. 112
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16 June 2010 16:29 [Source: ICIS news]
WASHINGTON (ICIS news)--US wholesale prices for organic chemicals and plastic resins fell in May, the Labor Department said on Wednesday, part of a general decline in overall producer prices.
The department said that prices paid at the producer level - also known as wholesale prices - declined by 0.4% in May from April for basic organic chemicals.
That downturn followed month-to-month wholesale price gains for chemicals of 3.2% in March and 0.6% in April.
For plastic resins and materials, the producer price decline in May was much sharper, falling by 7.6% compared with April.
The May decline followed an 11.4% gain in April and a 1.8% drop in March.
Overall, the department said its producer price index (PPI) edged down by 0.3% in May and marked a second straight monthly decline after April’s marginal 0.1% drop.
Most of the decline in overall wholesale prices last month was attributed to a 1.5% decline in energy products, chiefly gasoline, and a 0.6% drop in consumer foods.
If energy and food products are taken out of the overall wholesale prices data, producer prices for all other goods rose slightly by 0.2% in May, the department said.
Economists typically look at producer prices minus fuels and foods - the so-called core wholesale prices - because those two categories frequently show wide month-to-month swings.
With the core producer prices data showing that modest 0.2% increase in May, economists saw little threat of inflationary pressures. That in turn would allow the Federal Reserve Board, the ?xml:namespace>. | http://www.icis.com/Articles/2010/06/16/9368560/us-wholesale-prices-decline-for-chemicals-plastics-in-may.html | CC-MAIN-2013-20 | refinedweb | 274 | 68.26 |
Test-driven development (TDD) is all the rage these days and has been a discussion topic for quite some time. If you are brand new to TDD, this article should serve as a good introduction to what TDD is, why it’s useful, what a typical TDD workflow looks like, and when to use TDD.
We’ll even go through an example in which we build a caesar cipher in JavaScript with Jest to run our unit tests.
Let’s get started.
What is TDD?
What is test-driven development? In short, it’s a development strategy in which you write your tests first, then your app code.
In other words, product requirements are turned into very specific test cases, and then the software is improved so that the tests pass.
This is the opposite of a workflow in which you write your app code first and then your tests second. To be clear, either of these approaches are far superior to not having any unit tests at all.
The “Red, Green, Refactor” Cycle
TDD can be more easily understood by looking at a simple diagram:
- Write a failing test. You’re writing your tests before your app code, so you know this test is going to fail. You haven’t implemented the feature yet! This is considered the “red” state (some tests failing).
- Make the test pass. Here you write your app code, so you actually implement whatever functionality the test is looking at. Once you have your test passing, you’re now in the “green” state (all tests passing).
- Refactor. Now that your test is passing, go make your code better. As the famous quote from Kent Beck goes: “Make it work. Make it right. Make it better. In that order.” Note that we don’t refactor until we’re in the “green” state. By having all our tests passing, we can refactor with confidence because if we break something, tests will start failing again, letting us know our refactor isn’t working perfectly yet.
- Repeat. Go write another test now! Continue to loop through steps 1–3 as you write more tests and implement more functionality in your app.
Why use TDD?
Ok, so that’s what TDD is and how the development process works. But why should you use it? There are several benefits to using TDD, but here are three:
- Tests are built right into your development cycle, not as an afterthought.
- It makes sure your tests are testing the right things.
- Every branch is covered (in theory).
Let’s explore each of these benefits.
Tests are built right into your development cycle, not as an afterthought.
Have you ever written all your app code, and then gone back and thought, “As a responsible developer I should probably write some tests for this code” and then dreaded the next few hours or days of writing tests?
Or has writing the tests ever felt pointless? After all, you’ve already manually tested your code, and it seems to be working fine, so why bother writing tests now? Let’s just ship it.
When you use TDD, however, tests are just part of your development process. Because you are writing them at the same time that you’re writing your app code, the tests feel more meaningful, and you know that they are actually serving some purpose.
(Side note: Tests are more for the future than for the present. While they’re helpful in verifying your functionality is working now, they’re even more useful when the next developer three months from now has to modify some of your code. If tests are in place, he or she can refactor with confidence. It’s especially nice when that developer is you!)
It makes sure your tests are testing the right things.
If your tests are being written directly based on product requirements, then hopefully your tests are testing the core functionality that the end users care about. Simple enough.
By writing tests based on product requirements, you are also documenting the acceptance criteria for your app, in a way. Remember to avoid testing internal implementation details as much as possible!
Every branch is covered (in theory).
If you’re writing your tests after your app code, do you ever find yourself struggling to hit those last few percentages of code coverage?
There are debates on how much code coverage is enough (80%? 90%? 95%? 100%?), but in general I feel like your code should have close to 100% code coverage. It’s nice to know that there are no hidden corners of your application that are lacking tests, especially if those spots are crucial parts of your application.
In practice, 100% code coverage probably isn’t always realistic or worth your time, but it’s a good ideal to strive for.
A nice side effect of using TDD is that it should result in 100% code coverage. If all the app code you're writing is to satisfy tests, then in theory you shouldn’t have written any app code that isn’t being tested.
If you have an if/else statement in your app code where two possible outcomes could occur, it’s very likely you had some sort of product requirement stating “if A, then B should happen; if C, then D should happen”.
For example, “If the user is logged in, they should be able to see this page content. If the user is not logged in, they should not be able to see this page content.”
When should you use TDD?
It’s important to note that TDD is not a magic bullet. It won’t solve all your problems, and there are definitely cases where it doesn’t make sense to use TDD.
TDD is great when you:
- have clear project requirements
- have clear inputs and outputs (pure functions, API endpoints)
- are fixing bugs!
Clear Project Requirements
It’s hard to write your test cases up front if you don’t have clear project requirements. However, if you know exactly what the acceptance criteria are and what the expected functionality is, go start writing your tests!
Clear Inputs and Outputs
Same for when you have clear inputs and outputs. If you are writing a currency formatting function, and you know that
formatCurrency(3.50, 'USD') should result in
$3.50, then go write your tests first!
Think of all the weird input you could get and how would you handle it. What if your method was called with missing arguments, like
formatCurrency()? What if a string was passed instead of a number, like
formatCurrency('sorry', 'CAD')? How would you handle those cases? What would your method do? Return
undefined or
null? Throw an error?
Writing your tests upfront allows you to think about all those edge cases and then helps you write your function so that it behaves properly.
Bug Fixes
Do you have a bug you’re fixing? Great! Write a test for what should be happening when the app is functioning properly. Now go fix the bug. Look at you! You just did some TDD!
A huge benefit to this approach is also that you’ve now written a test to help ensure this particular bug won’t creep back into your application again.
When not to use TDD?
TDD probably doesn’t make sense for:
- exploratory programming
- UI development (debatable)
Exploratory Programming
If you don’t know what exactly you're building, or if you don’t have clear requirements, then it’s really hard to write tests first, because you don’t know what the expected behavior should be! If you’re experimenting with something or trying out something new in your app, TDD might not make sense to use.
UI Development
This one I’m still undecided on, so I would love to hear anyone’s thoughts and opinions on this. In the past, I’ve avoided doing TDD when developing UIs because most of the time, I don’t know perfectly beforehand what HTML elements I’m going to use, or what my app state will look like, or what functions I’ll end up writing.
That’s not to say that TDD is impossible in this case, it just takes a little more forethought. And maybe that’s not such a bad thing.
However, the new frontend testing philosophies that are starting to emerge seem like they would make TDD with UI development make much more sense.
In particular, the React world seems to be moving away from using Enzyme, which allows you to shallow render and to test implementation details of your components, and moving towards Kent Dodds’ React Testing Library, which emphasizes testing things that a user could actually see and interact with.
So rather than writing tests stating that some function will be called and it will change the state in some way, you would test that some button is present on the page, and that when the button is clicked, some other text or data is present on the page after that.
This seems like a much more approachable way to do TDD while developing UIs.
Demo
Demo time! Let’s see what a typical development process might look like when using TDD while creating a caesar cipher implemented in JavaScript.
All the code that follows can be found on GitHub here.
If you’re not familiar with what a caesar cipher is, it’s a very simple method of “encoding” a message, which the person receiving the message can then “decode”. The message is encoded by shifting each letter in the message by a specified amount and then decoded by shifting each letter in the opposite direction by that same amount.
For example, if the un-encoded message is
Hello world!, and the shift amount is 5, then the encoded message becomes
Mjqqt btwqi!. The “H” moves forward 5 letters in the alphabet to “M”, the “e” moves forward 5 letters in the alphabet to “j”, and so on.
Product Requirements
Ok, so what might our product requirements be? Let’s define them as:
- takes a string and a shift value and returns a new string
- shifts the A-Z characters by the correct amount
- does not affect non-alphabetic characters
- maintains case and handles uppercase and lowercase letters
- handles wrapping past the end of the alphabet
- handles shift values greater than 26
- handles shift values less than 0
- handles bad input
Initial app code and test code
Let’s say that we’ll have two files:
caesar-cipher.js and
caesar-cipher.test.js.
The test file looks like this:
import { encode } from './caesar-cipher' describe('caesar cipher', () => { // TODO: write tests here })
And the source code looks like this:
export const encode = () => {}
Requirement 1: takes a string and a shift value and returns a new string
Let’s write our test first by putting this test inside the
describe block:
it('takes a string and a shift value and returns a new string', () => { expect(typeof(encode('abc', 1))).toBe('string') })
The test fails! And of course it will, because we just have an empty shell of an
encode method right now that just returns
undefined.
Now let’s write our source code to make the test pass:
export const encode = (str, shiftAmount) => { return str }
This is just returning the original string that the method is passed, but that’s ok for now. Our test is just concerned with the type of data the method returns, so with this test passing, we’re ready to move on to the next product requirement.
Requirement 2: shifts the A-Z characters by the correct amount
Our test will be:
it('shifts the A-Z characters by the correct amount', () => { expect(encode('abc', 1)).toBe('bcd') expect(encode('test', 2)).toBe('vguv') })
The test fails! And that’s expected, because again, we’re not encoding the string yet. We’re just returning the original unmodified string.
Let’s write some source code to meet this requirement:
export const encode = (str, shiftAmount) => { const encryptedMessage = str.split('').map((character, index) => { const code = str.charCodeAt(index) const shiftedCode = code + shiftAmount return String.fromCharCode(shiftedCode) }) return encryptedMessage.join('') }
This code splits the string into an array of characters and then loops over them. For each character, it finds the character code, adds the shift amount to it, and then gets the character from the new character code. It then joins the array back into a string and returns our encrypted message.
All tests are passing now, so we can move on to our next product requirement.
Requirement 3: does not affect non-alphabetic characters
Let’s write a test:
it('does not affect non-alphabetic characters', () => { expect(encode('abc123', 1)).toBe('bcd123') })
The test fails! Our method is shifting the numbers as well as the letters. Let’s modify our source code to address this:
export const encode = (str, shiftAmount) => { const encryptedMessage = str.split('').map((character, index) => { const code = str.charCodeAt(index) // 97-122 => a-z if (code >= 97 && code <= 122) { const shiftedCode = code + shiftAmount return String.fromCharCode(shiftedCode) } return character }) return encryptedMessage.join('') }
Now we’re only transforming characters that fall into the character code range of 97–122, which maps to the characters a-z.
Let’s move on to our next requirement.
Requirement 4: maintains case and handles uppercase and lowercase letters
Here’s our test:
it('maintains case', () => { expect(encode('aBc', 1)).toBe('bCd') })
The test fails! Again, our method is only transforming characters in the 97–122 character code range, which means that while we’re handling lowercase a-z, we’re ignoring uppercase A-Z. Let’s also add the correct range for that, which is 65–90:
export const encode = (str, shiftAmount) => { const encryptedMessage = str.split('').map((character, index) => { const code = str.charCodeAt(index) // 97-122 => a-z; 65-90 => A-Z if ((code >= 97 && code <= 122) || (code >= 65 && code <= 90)) { const shiftedCode = code + shiftAmount return String.fromCharCode(shiftedCode) } return character }) return encryptedMessage.join('') }
There we go, much better. On to the next requirement.
Requirement 5: handles wrapping past the end of the alphabet
Let’s write our test:
it('handles wrapping past the end of the alphabet', () => { expect(encode('xyz', 2)).toBe('zab') })
The test fails! Rather than wrapping the letters at the end of the alphabet back to the beginning of the alphabet, the method is just moving each character to the shifted character code, even if that character code is outside of our range.
To fix this, we can make use of the modulo operator:
export const encode = (str, shiftAmount) => { const encryptedMessage = str.split('').map((character, index) => { const code = str.charCodeAt(index) // 97-122 => a-z; 65-90 => A-Z if (code >= 65 && code <= 90) { const shiftedCode = ((code + shiftAmount - 65) % 26) + 65 return String.fromCharCode(shiftedCode) } else if (code >= 97 && code <= 122) { const shiftedCode = ((code + shiftAmount - 97) % 26) + 97 return String.fromCharCode(shiftedCode) } return character }) return encryptedMessage.join('') }
Now our messages will wrap properly around the ends of the alphabet. Next requirement.
Requirement 6: handles shift values greater than 26
Similar to how letters near the end of the alphabet should wrap properly, using a large shift amount should wrap properly too. For example, even the letter “a” shifted by 28 moves further than the full length of the alphabet, so it needs to wrap to become “c”.
Here’s our test:
it('handles shift values greater than 26', () => { expect(encode('abc', 26)).toBe('abc') expect(encode('abc', 28)).toBe('cde') })
And… the test passes! Would you look at that. It turns out that our modulo operator we used during requirement 5 helped us out here with requirement 6.
So, no new source code to write at the moment. And that’s ok. Sometimes you’ve already covered the test case, whether intentionally or unintentionally.
Let’s move on to the next requirement.
Requirement 7: handles shift values less than 0
What if we wanted to shift our characters in the other direction by using a negative shift amount? We’ll need to make sure our letters will wrap properly from the beginning of the alphabet back around to the end of the alphabet.
Here’s our test:
it('handles shift values less than 0', () => { expect(encode('abc', 0)).toBe('abc') expect(encode('abc', -2)).toBe('yza') })
The test fails! Ok let’s go fix this in our source code by also applying the modulo operator to the shift amount:
export const encode = (str, shiftAmount) => {('') }
This ensures that our shift amount is always transformed into a positive number when we start to encode our characters.
Requirement 8: handles bad input
Last but not least, let’s make sure our method can gracefully respond to bad input or when it is used incorrectly.
Our test will be:
it('handles bad input', () => { expect(encode()).toBe('') expect(encode(1, 1)).toBe('') expect(encode(1, 'abc')).toBe('') expect(encode('abc')).toBe('abc') })
We could probably write some more expectations as well, but this at least looks for missing arguments and incorrect argument types.
Let’s update our source code to handle this now:
export const encode = (str = '', shiftAmount = 0) => { if (typeof str !== 'string' || typeof shiftAmount !== 'number') { return '' }('') }
Adding some default values and doing some type checking makes the test pass. We did it! All 8 requirements are now complete.
If you were to check the code coverage on our caesar cipher right now, you’d see that we have 100% code coverage. Awesome! While this code isn’t incredibly complex, we did have some default values for the function parameters, and we had some branching logic looking at the value types and the character codes.
By using TDD, we’ve made sure every condition of our method is adequately tested, so we can use the caesar cipher in our made up app with confidence.
Conclusion
Well, that’s it for now! We’ve gone over what TDD is, why it’s useful, what a typical TDD workflow looks like, when to use TDD, when not to use TDD, and even did some hands-on TDD to write our
encode method for our caesar cipher.
If you want some more practice, go write a
decode method!
Discussion (2)
I've seen a lot of people talk about how good TDD is and they provide lots of contrived examples but personally I have found that not having clear requirements and not having clear inputs and outputs are the norm. I can't remember the last time I worked on anything of even low complexity where I knew how the end result would look ahead of time, enough to write tests. In my experience, almost all programming is exploratory.
That said, I do find TDD more applicable at the function level, rather than the application level. It ties in with the benefits of pure functions since these are easier to test in isolation and it is more common for a pure function to have a set interface defined ahead of time.
But for anything larger than a few thousand lines of code (which I would consider small), the whole process of building the application involves exploration around which interface works best. This includes the boundary between user and application as well as boundaries between various subsystems. It would be counter productive to write the tests first and then be constrained to stick with what could well be a sub-optimal design. My applications typically take the form of building a proof of concept, then iterating over the design until it feels right (efficient, less code, low on resources, easy to maintain) and then optimising where it makes sense. During that process the interface will almost always change. I feel like TDD requires a crystal ball, and the one constant in the software industry is changing requirements.
Sorry I realise this comes across as arguing against TDD but really I just want to hear how people would apply TDD at the application level. How often do you write software where the design and interface is fully known at the start and doesn't change?
As I said if I'm writing a function or a small subsystem that seems critical and has a clear interface, then yes I'll write a unit test. Most of the time everything I write is open to be refactored, and the reliability is crafted into the app design in other ways (good data structures, types etc). I write more unit tests for things that are designed to be reused a lot. But I still write them after the fact. Because that is after the interface has been worked out via trial and error.
TDD is always my favorite topic of software development. Don't forget about the three rules of TDD | https://dev.to/thawkin3/an-introduction-to-test-driven-development-1bfp | CC-MAIN-2022-05 | refinedweb | 3,462 | 72.26 |
Hi All, This appears to be a bug in IE, not prototype, as it is not applying the class attribute using the specified 'className' property (http:// msdn.microsoft.com/en-us/library/ms533560(VS.85).aspx), but using the attribute name 'class' instead, so as a work around I have added this around line 1809 in prototype.js:
Advertising
if (Prototype.Browser.IE && (parseFloat(navigator.appVersion.split ("MSIE")[1]) >= 8.0) && (name == "className")) name='class'; so it now looks like: ... name = t.names[attr] || attr; if (Prototype.Browser.IE && (parseFloat(navigator.appVersion.split ("MSIE")[1]) >= 8.0) && (name == "className")) name='class'; value = attributes[attr]; ... This seems to fix the problem and I have tested in IE7, IE8, FF3, Opera 9.5, Safari 3 and Chrome 2.0 (all on Windows) and it appears to have no other side effects. Kinds regards, Andrew Completely Free Dating On Mar 21, 12:22 pm, "T.J. Crowder" <t...@crowdersoftware.com> wrote: > @masterleep: > > I think there are still some IE8 issues. Now that a final is out, > they'll probably get resolved soon. I know kangax (at least) is > working on some of them and several have already been resolved in the > trunk version. Would you give the trunk version a go? > > @RobG: > > > Then that is a bug in IE 8. > > It _may_ be. Half the point of readAttribute it that it "...cleans up > the horrible mess Internet Explorer makes when handling attributes"[1] > and consequently it does a *lot* of processing around the getAttribute > call, including (in trunk) several IE8-specific branches. Always > possible that that code isn't handling something right. Equally, it's > entirely possible that there's a (new) bug in IE8. :-) I don't > currently have a machine I can load IE8 on to find out whether the > fault is in IE8's getAttribute or Prototype's readAttribute. > > [1] > > -- > T.J. Crowder > tj / crowder software / com > Independent Software Engineer, consulting services available > > On Mar 21, 11:29 am, RobG <rg...@iinet.net.au> wrote: > > > On Mar 20, 6:18 am, masterleep <bill-goo...@lipa.name> wrote: > > > > OK, I found this particular one... if you call > > > input_elem.readAttribute('value'); > > > on an input element, and the value is equal to the empty string, then > > > in IE8 the result is null. > > > Then that is a bug in IE 8. readAttribute uses getAttribute, which > > returns a string in browsers that are compliant with the W3C DOM Core > > spec: > > > <URL:> > > > > On other browsers, the result is the empty > > > string. > > > Which is compliant with the spec. > > > An alternative is to use the DOM property for HTML attributes (i.e. > > inputElement.value) - what does that return (I don't have access to IE > > 8 at the moment)? > > > -- > > Rob --~--~---------~--~----~------------~-------~--~----~ -~----------~----~----~----~------~----~------~--~--- | https://www.mail-archive.com/prototype-scriptaculous@googlegroups.com/msg04854.html | CC-MAIN-2017-34 | refinedweb | 452 | 67.86 |
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