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This article explains how to use and manipulate strings in C++.
Strings are an integral part of any programming language due to their ability to store text. In C++, there are dozens of different methods and functions that can be used to manipulate these strings. We’ll be explaining how to create strings and use these methods on them in this C++ string tutorial.
Creating a String in C++
There are two steps to creating a string in C++. First you must import the string library by including an additional header file with the following line.
#include <string>
Next you actually have to declare the string. You can choose to simply declare a string variable, or declare it with an initial value as well. Both ways are shown below.
Without a value:
string name;
With a value:
string name = "Coder";
Accessing Strings
Just like other programming languages, indexing in C++ starts from zero. What this means is that the “index” or “position number” assigned to to first character in a string is not 1, it is 0.
Below is a simple diagram we came up with to demonstrate this effect.
Learning how to access strings correctly has a large number of benefits. Indexing plays a huge role in retrieving individual characters from strings, locating substrings, iterating over strings etc.
Accessing individual characters
#include <iostream> #include <string> using namespace std; int main () { string x = "Hello World"; cout << x[0]; }
H
cout << x[6];
W
cout << x[8];
r
Iterating over a String
Using a for loop, you can easily iterate over a string. You may not see the use of this right now, but later it will help in fields like data analysis (like locating substrings) and such.
There’s more than one way of doing this, but we’ve chosen the following method for it’s simplicity and small size.
First we create a string called
str with some random text. Next we create a for loop and declare a variable of datatype of char called
c. The string we declared earlier is separated from the char data type by
:.
With this format, every iteration of the for loop will load a new character from the string (
str) into the variable
c. Adding a simple
cout line that prints the value of c each iteration shows us this perfectly.
#include <iostream> #include <string> using namespace std; int main() { string str = "Hello"; for(char& c : str) { cout << c; cout << "\n"; } }
H e l l o
String Concatenation
String Concatenation refers to the process where two or more strings are combined together into one. There are two ways of doing so in C++ that we’ll discuss below.
The simpler way of doing so is just to use the
+ between two strings (or more) to combine them.
#include <iostream> #include <string> using namespace std; int main () { string x, y; cout << "Enter string x: "; cin >> x; cout << "Enter string y: "; cin >> y; cout << x + y; }
Enter string x: hello Enter string y: world helloworld
The other way is to use the
append() method which is the more “proper” way of concatenating strings in C++.
int main () { string x, y; cout << "Enter string x: "; cin >> x; cout << "Enter string y: "; cin >> y; cout << x.append(y); }
Enter string x: C++ Enter string y: strings C++strings
Converting Strings (and Vice versa)
In this section we’ll explain how to convert strings to other data types, as well as converting other data types to strings. Converting strings to numbers is the most common, so we’ll cover the conversion to both integer and decimal values.
Using string streams from the sstream library we make these conversions possible. First step is to create a stream object from the string you wish to convert. Next you just have “stream” it to the variable x by using the
>> operator.
#include <iostream> #include <sstream> using namespace std; int main() { string text = "123"; stringstream stream(text); int x; stream >> x; cout << "Value of x : " << x; }
123
The value is just the same, but of a different type. You can use method to convert to integer, double, float and other number related data types.
Other methods
A few other useful things you can do with strings in C++ using methods.
substr(n1, n2)
The
substr() method is meant to locate sub strings within a string. It takes two arguments as input, a start index and a stop index. Everything in between (including the start index) is returned as a sub string (excluding the stop index).
int main () { string x = "Hello World"; cout << x.substr(0,5); }
Hello
size method
A simple but important function that returns the size or “length” of the string.
int main () { string x = "Hello World"; cout << x.size(); }
11
This marks the end of the Strings in C++ tutorial. Any suggestions or contributions for CodersLegacy are more than welcome. Questions regarding the article content can be asked in the comments section below.
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https://coderslegacy.com/c/c-strings/
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Host software for 3D printers
Project description
PRINTRUN 2.X
The master branch holds the development of Printrun 2.x. This new version of Printrun supports Python 3 and wxPython 4. All new features and developments should be merged to it.
Note for OSX users: if OSX tells you the file is corrupted, you don't need to redownload it. Instead, you need to allow OSX to run unsigned apps. To do this, run
sudo spctl --master-disable
Linux
Ubuntu/Debian
There is currently no package for Printrun 2. It must be run from source.
Chrome OS
You can use Printrun via crouton ( ). Assuming you want Ubuntu Trusty, you used probably
sudo sh -e ~/Downloads/crouton -r trusty -t xfce to install Ubuntu. Fetch and install printrun with the line given above for Ubuntu/Debian.ora
You can install Printrun from official packages. Install the whole package using
sudo dnf install printrun
Or get only apps you need by
sudo dnf install pronsole or
pronterface or
plater
Adding
--enablerepo updates-testing option to
dnf might sometimes give you newer packages (but also not very tested).
Archlinux
Packages are available in AUR. Just run
yaourt printrun
and enjoy the
pronterface,
pronsole, ... commands directly.
RUNNING FROM SOURCE
Run Printrun for source if you want to test out the latest features.
Dependencies
To use pronterface, you need:
- Python 3 (ideally 3.6),
- pyserial (or python3-serial on ubuntu/debian)
- pyreadline (not needed on Linux)
- wxPython 4
- pyglet
- appdirs
- numpy (for 3D view)
- pycairo (to use Projector feature)
- cairosvg (to use Projector feature)
- dbus (to inhibit sleep on some Linux systems)
Use Python virtual environment
Easiest way to run Printrun from source is to create and use a Python virtual environment. The following section assumes Linux. Please see specific instructions for Windows and macOS X below.
Ubuntu/Debian note: You might need to install
python3-venv first.
Note: wxPython4 doesn't have Linux wheels available from the Python Package Index yet. Find a proper wheel for your distro at extras.wxpython.org and substitute the link in the bellow example. You might skip the wheel installation, but that results in compiling wxPython4 from source, which can be time and resource consuming and might fail.
$ git clone # clone the repository $ cd Printrun # change to Printrun directory $ python3 -m venv venv # create an virtual environment $ . venv/bin/activate # activate the virtual environment (notice the space after the dot) (venv) $ python -m pip install # replace the link with yours (venv) $ python -m pip install -r requirements.txt # intall the rest of dependencies (venv) $ python pronterface.py # run Pronterface
Cython-based G-Code parser
Printrun default G-Code parser is quite memory hungry, but we also provide a much lighter one which just needs an extra build-time dependency (Cython), plus compiling the extension with:
(venv) $ python -m pip install Cython (venv) $.
Ubuntu/Debian
The above method is the recommended way to run Printrun 2 from source. However, if you can't find a suitable wxPython4 wheel, or if it fails for other reasons, it could be run without using a python virtual environment. For users of Debian 10 Buster or later and Ubuntu 18.04 Bionic Beaver or later.
Install the dependencies:
sudo apt install python3-serial python3-numpy cython3 python3-libxml2 python3-gi python3-dbus python3-psutil python3-cairosvg libpython3-dev python3-appdirs python3-wxgtk4.0
sudo apt install python3-pip pip3 install --user pyglet
Install git, clone this repository:
sudo apt install git git clone cd Printrun
Windows
Download and install Python 3.6 and follow the Python virtual environment section above except use the following to create and activate the virtual environment and install dependencies:
> py -3 -m venv venv > venv\Scripts\activate > python -m pip install -r requirements.txt
macOS X
Install Python 3, you can use Brew:
$ brew install python3
And follow the above Python virtual environment section. You don't need to search for wxPython wheel, macOS wheels are available from the Python Package Index.
USING PRINTRUN or Skeinforge and add its path to the settings.
Slic3r integration
To invoke Slic3r directly from Pronterface your slicing command (Settings > Options > External Commands > Slice Command) should look something like
slic3r $s -o $o. If Slic3r is properly installed "slic3r" will suffice, otherwise, replace it with the full path to Slic3r's executable.
If the Slic3r integration option (Settings > Options > User interface > Enable Slic3r integration) is checked a new menu will appear after application restart which will allow you to choose among your previously saved Slic3r Print/Filament/Printer settings.
USING PRONSOLE
To use pronsole, you need:
- Python 3 (ideally 3.6),
- pyserial (or python3 3 (ideally 3.6) and pyserial (or python3-serial on ubuntu/debian) See pronsole for an example of a full-featured host, the bottom of printcore.py for a simple command-line sender, or the following code example:
Printrun provides two platers: a STL plater (
plater.py) and a G-Code plater (
gcodeplater.py).
3
pronterface and
pronsole start a RPC server, which runs by default
on localhost port 7978, which provides print progress information.
Here is a sample Python script querying the print status:
import xmlrpc.client rpc = xmlrpc.client.ServerProxy('') print(rpc.status())
CONFIGURATION
Build
Macros90 ..>
Copyright (C) 2011-2020 Kliment Yanev, Guillaume Seguin.
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/Printrun/
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Plot pT hard dependent histograms of analysis EMCal PWG-GA QA wagon. More...
#include "TString.h"
#include "TH1F.h"
#include "TH2F.h"
#include "TFile.h"
#include "TCanvas.h"
#include "TPad.h"
#include "TStyle.h"
#include "TLine.h"
#include "TLegend.h"
#include "TMath.h"
#include "TGaxis.h"
Go to the source code of this file.
Plot pT hard dependent histograms of analysis EMCal PWG-GA QA wagon.
Macro to plot few selected histograms to QA MC productions done with pT hard bins (pythia jet-jet)./ Do plots with the calculated scaling factor per pT hard bin and without the scaling. The plots are:
To execute:root -q -b -l DrawPtHardBins.C'(1,50,20,1,kFALSE)'
The input files Scaled.root and NotScaled.root are obtained executing the script:
This script: 1 downloads the analysis QA train output files per pT hard bin and run, 1 merges the files per run in each pT hard bin, 1 extracts the histograms of the EMCAL QA wagon in 2 separate files, in one of them it scales the histograms with the proper cross section 1 adds the different pT hard bins
Definition in file DrawPtHardBins.C.
Main method, produce the plots.
Input:
Definition at line 63 of file DrawPtHardBins.C.
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http://alidoc.cern.ch/AliPhysics/vAN-20180306/_draw_pt_hard_bins_8_c.html
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Compile-time Sequences
Background
Compile-time sequences are an important metaprogramming concept that comes naturally from D support for variadic templates. They allow a programmer to operate on types, symbols and values, enabling the ability to define compile-time algorithms that operate on types, symbols and values.
Note: For historical reasons these sequences can sometimes be called tuples in documentation or compiler internals, but don't get confused - they don't have much in common with tuples that commonly exist in other languages. Sequences of values of different types that can be returned from functions are provided by std.typecons.Tuple. Using the term "tuple" to mean compile-time sequences is discouraged to avoid confusion, and if encountered should result in a documentation bug report.
Consider this simple variadic template:
template Variadic(T...) { /* ... */ }
T here is a TemplateParameterSequence, which is a core language feature. It has its own special semantics, and, from the programmer's point of view, is most similar to an array of compile-time entities - types, symbols (names) and values. One can check the length of this sequence and access any individual element:
template Variadic(T...) { static assert (T.length > 1); pragma(msg, T[0]); pragma(msg, T[1]); } alias dummy = Variadic!(int, 42); // prints during compilation: // int // 42
AliasSeq
The language itself does not provide any means to define such sequences outside of a template parameter declaration. Instead, there is a simple utility provided by the standard library:
alias AliasSeq(T...) = T;
All it does is give a specific variadic argument sequence an externally accessible name so that it can be worked with in any other context:
import std.meta; // can alias to some other name alias Name = AliasSeq!(int, 42); pragma(msg, Name[0]); // int pragma(msg, Name[1]); // 42 // or work with a sequence directly pragma(msg, AliasSeq!("aaa", 0, double)[2]); // double
Available operations
Checking the length
import std.meta; static assert (AliasSeq!(1, 2, 3, 4).length == 4);
Indexing and slicing
Indexes must be known at compile-time
import std.meta; alias Numbers = AliasSeq!(1, 2, 3, 4); static assert (Numbers[1] == 2); alias SubNumbers = Numbers[1 .. $]; static assert (SubNumbers[0] == 2);
Assignment
Works only if the sequence element is a symbol that refers to a mutable variable
import std.meta; void main() { int x; alias seq = AliasSeq!(10, x); seq[1] = 42; assert (x == 42); // seq[0] = 42; // won't compile, can't assign to a constant }
Loops
D's foreach statement has special semantics when iterating over compile-time sequences. It repeats the body of the loop for each of the sequence elements, with the loop iteration symbol being an alias for each compile-time sequence element in turn.
import std.meta; void main() { foreach (sym; AliasSeq!(int, "literal", main)) { static if (is(sym)) pragma (msg, sym); else pragma (msg, typeof(sym)); } } /* Prints: int string void() */
Note: Static foreach should be preferred in new code.
Auto-expansion
One less obvious property of compile-time argument sequences is that when used as an argument to a function or template, they are automatically treated as a sequence of comma-separated arguments:
import std.meta; template Print0(T...) { pragma(msg, T[0]); } alias Dummy = Print0!(AliasSeq!(int, double));
This will only print int during compilation because the last line gets rewritten as alias Dummy = Print0!(int, double). If auto-expansion didn't happen, AliasSeq!(int, double) would be printed instead. This is an inherent part of the language semantics for variadic sequences, and thus also preserved by AliasSeq.
Homogenous sequences
An AliasSeq that consists of only type or value elements are commonly called "type sequences" or "value sequences" respectively. The concept of a "symbol sequence" is used less frequently but fits the same pattern.
Type sequences
It is possible to use homogenous type sequences in declarations:
import std.meta; alias Params = AliasSeq!(int, double, string); void foo(Params); // void foo(int, double, string);
Type sequence instantiation
D supports a special variable declaration syntax where a type sequence acts as a type:
import std.meta; void foo() { AliasSeq!(int, double, string) variables; variables[0] = 42; variables[1] = 42.0; variables[2] = "just a normal variable"; }
The compiler will rewrite such a declaration to something like this:
int __var1; double __var2; string __var3; alias variables = AliasSeq!(__var1, __var2, __var3);
So a type sequence instance is a kind of symbol sequence that only aliases variables, known as an lvalue sequence.
Variadic template functions use a type sequence instance for a function parameter:
void foo(T...)(T args) { // 'T' is a type sequence of argument types. // 'args' is an instance of T whose elements are the function parameters static assert(is(typeof(args) == T)); args[0] = T[0].init; }
Note: std.typecons.Tuple wraps a type sequence instance, preventing auto-expansion, and allowing it to be returned from functions.
Value sequences
It is possible to use a sequence of values of the same type to declare an array literal:
import std.meta; enum e = 3; enum arr = [ AliasSeq!(1, 2, e) ]; static assert(arr == [ 1, 2, 3 ]);
The above sequence is an rvalue sequence, as it is comprised only of literal values and manifest constants. Each element's value is known at compile-time.
The following demonstrates use of an lvalue sequence:
import std.meta, std.algorithm; auto x = 3, y = 7; alias pair = AliasSeq!(x, y); swap(pair); assert(x == 7 && y == 3);
As above, such sequences may use assignment.
Aggregate field sequences
.tupleof is a class/struct instance property that provides an lvalue sequence of each field.
Symbol sequences
A symbol sequence aliases any named symbol - types, variables, functions and templates - but not literals. Like an alias sequence, the kind of elements can be mixed.
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https://dlang.org/articles/ctarguments.html
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Lets say I have a set of a class
Action like this:
actions: Set[Action], and each
Action class has a
val consequences : Set[Consequence], where
Consequence is a case class.
I wish to get a map from
Consequence to
Set[Action] to determine which actions cause a specific
Consequence. Obviously since an
Action can have multiple
Consequences it can appear in multiple sets in the map.
I have been trying to get my head around this (I am new to Scala), wondering if I can do it with something like map() and groupBy(), but a bit lost. I don't wish to revert to imperative programming, especially if there is some Scala mapping function that can help.
What is the best way to achieve this?
Not exactly elegant because
groupBy doesn't handle the case of operating already on a
Tuple2, so you end up doing a lot of tupling and untupling:
case class Conseq() case class Action(conseqs: Set[Conseq]) def gimme(actions: Seq[Action]): Map[Conseq, Set[Action]] = actions.flatMap(a => a.conseqs.map(_ -> a)) .groupBy(_._1) .mapValues(_.map(_._2)(collection.breakOut))
The first line "zips" each action with all of its consequences, yielding a
Seq[(Conseq, Action)], grouping this by the first product element gives
Map[Conseq, Seq[(Conseq, Action)]. So the last step needs to transform the map's values from
Seq[(Conseq, Action)] to a
Set[Action]. This can be done with
mapValues. Without the explicit builder factory, it would produce a
Seq[Action], so one would have to write
.mapValues(_.map(_._2)).toSet. Passing in
collection.breakOut in the second parameter list to
map makes it possible to save one step and make
map directly produce the
Set collection type.
Another possibility is to use nested folds:
def gimme2(actions: Seq[Action]) = (Map.empty[Conseq, Set[Action]] /: actions) { (m, a) => (m /: a.conseqs) { (m1, c) => m1.updated(c, m1.getOrElse(c, Set.empty) + a) } }
This is perhaps more readable. We start with an empty result map, traverse the actions, and in the inner fold traverse each action's consequences which get merged into the result map.
|
http://www.dlxedu.com/askdetail/3/9998d2e54a821defe87f2fd04b8a7a1c.html
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Ticket #854 (closed enhancement: worksforme)
Request - Startup Hook
Description
It would be nice if TG supported some user defined startup code that can be called from startup.startTurboGears()
i think it might support it already - but there are no docs for it
It'd be nice, because then we can set certain variables and/or add some cherrypy filters to access the filter API
Attachments
Change History
Changed 13 years ago by anonymous
- attachment startup.diff
added
comment:1 Changed 13 years ago by jvanasco@…
OK. I patched startup.py myself
this now supports 3 arguments in app.cfg
# filter to preprend to the list tg.udf_cpfilter_pre = 'appname.module.filtername' # filter to append to the list tg.udf_cpfilter_post = 'appname.module.filtername' # function to call on startup tg.udf_startup = 'appname.module.functionname'
if someone can do a better job, please do. this was the only way i could push stuff into cherrypy though - before startup is called in start-appname.py, cherrypy.root isn't declared. elsewhere in the app , we're a request only phase
the filters seem good where they are, but there might be a better place for the udf (user defined function) startup function - perhaps later in the request , right before we enter the reactor loop - not sure where that happens though
comment:2 Changed 13 years ago by alberto
I think there's no need to patch startup for this. You can register any callable to be run at TG startup already:
from turbogears.startup import call_on_startup def insert_your_filters(): ... call_on_startup.append(insert_your_filters)
HTH, Alberto
comment:3 Changed 13 years ago by jvanasco@…
- Status changed from new to closed
- Resolution set to worksforme
i really wish that someone would have tossed that into the docs.
I'm adding a wiki page for the next person.
|
http://trac.turbogears.org/ticket/854
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score:1
Accepted answer
import img from "../../assets/img/logo(name).svg"; render() { return ( <div className="content" style={{ overflow: "auto"}}> <img id="logo-img" src={img} </div> ) }
Source: stackoverflow.com
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- How to pass key value pairs as parameters in Route Path?
- Conditional Rendering with React-semantic UI
- not able to display with reactjs
- React Redux state change
- How to turn HTML widget code into NEXTjs code to use in an app (CoinMarketCap Price Marquee Ticker)
- How to use NPM modules in plane javascript and html project?
- How to use value within JS forms and onSubmit. Do I NEED a submit button?
- How to use TypeScript and forwardRef in ReactJS?
- React / Redux and Multilingual (Internationalization) Apps - Architecture
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https://www.appsloveworld.com/reactjs/200/457/how-to-set-background-image-for-entire-screen-in-app-js-file-in-react-js
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UMAD_SET_ADDR(3) OpenIB Programmer's Manual UMAD_SET_ADDR(3)
umad_set_addr - set MAD address fields within umad buffer using host ordering
#include <infiniband/umad.h> int umad_set_addr(void *umad, int dlid, int dqp, int sl, int qkey);
umad_set_addr() sets the MAD address fields within the specified umad buffer using the provided host ordered fields. dlid is the destination LID. dqp is the destination QP (queue pair). sl is the SL (service level). qkey is the Q_Key (queue key).
umad_set_addr() returns 0 on success, and a negative value on errors. Currently, there are no errors indicated.
umad_set_addr_net(3)
Hal Rosenstock <halr@voltaire.com>IB May 17, 2007 UMAD_SET_ADDR(3)
Pages that refer to this page: umad_set_addr_net(3)
|
https://man7.org/linux/man-pages/man3/umad_set_addr.3.html
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Hosting your Models and Datasets on Hugging Face Spaces using Streamlit
Showcase your Datasets and Models using Streamlit on Hugging Face Spaces
Streamlit allows you to visualize datasets and build demos of Machine Learning models in a neat way. In this blog post we will walk you through hosting models and datasets and serving your Streamlit applications in Hugging Face Spaces.
Building demos for your models
You can load any Hugging Face model and build cool UIs using Streamlit. In this particular example we will recreate "Write with Transformer" together. It's an application that lets you write anything using transformers like GPT-2 and XLNet.
We will not dive deep into how the inference works. You only need to know that you need to specify some hyperparameter values for this particular application. Streamlit provides many components for you to easily implement custom applications. We will use some of them to receive necessary hyperparameters inside the inference code.
- The
.text_areacomponent creates a nice area to input sentences to be completed.
- The Streamlit
.sidebarmethod enables you to accept variables in a sidebar.
- The
slideris used to take continuous values. Don't forget to give
slidera step, otherwise it will treat the values as integers.
- You can let the end-user input integer vaues with
number_input.
import streamlit as st # adding the text that will show in the text box as default default_value = "See how a modern neural network auto-completes your text 🤗 This site, built by the Hugging Face team, lets you write a whole document directly from your browser, and you can trigger the Transformer anywhere using the Tab key. Its like having a smart machine that completes your thoughts 😀 Get started by typing a custom snippet, check out the repository, or try one of the examples. Have fun!" sent = st.text_area("Text", default_value, height = 275) max_length = st.sidebar.slider("Max Length", min_value = 10, max_value=30) temperature = st.sidebar.slider("Temperature", value = 1.0, min_value = 0.0, max_value=1.0, step=0.05) top_k = st.sidebar.slider("Top-k", min_value = 0, max_value=5, value = 0) top_p = st.sidebar.slider("Top-p", min_value = 0.0, max_value=1.0, step = 0.05, value = 0.9) num_return_sequences = st.sidebar.number_input('Number of Return Sequences', min_value=1, max_value=5, value=1, step=1)
The inference code returns the generated output, you can print the output using simple
st.write.
st.write(generated_sequences[-1])
Here's what our replicated version looks like.
You can checkout the full code here.
Showcase your Datasets and Data Visualizations
Streamlit provides many components to help you visualize datasets. It works seamlessly with 🤗 Datasets, pandas, and visualization libraries such as matplotlib, seaborn and bokeh.
Let's start by loading a dataset. A new feature in
Datasets, called streaming, allows you to work immediately with very large datasets, eliminating the need to download all of the examples and load them into memory.
from datasets import load_dataset import streamlit as st dataset = load_dataset("merve/poetry", streaming=True) df = pd.DataFrame.from_dict(dataset["train"])
If you have structured data like mine, you can simply use
st.dataframe(df) to show your dataset. There are many Streamlit components to plot data interactively. One such component is
st.barchart() , which I used to visualize the most used words in the poem contents.
st.write("Most appearing words including stopwords") st.bar_chart(words[0:50])
If you'd like to use libraries like matplotlib, seaborn or bokeh, all you have to do is to put
st.pyplot() at the end of your plotting script.
st.write("Number of poems for each author") sns.catplot(x="author", data=df, kind="count", aspect = 4) plt.xticks(rotation=90) st.pyplot()
You can see the interactive bar chart, dataframe component and hosted matplotlib and seaborn visualizations below. You can check out the code here.
Hosting your Projects in Hugging Face Spaces
You can simply drag and drop your files as shown below. Note that you need to include your additional dependencies in the requirements.txt. Also note that the version of Streamlit you have on your local is the same. For seamless usage, refer to Spaces API reference.
There are so many components and packages you can use to demonstrate your models, datasets, and visualizations. You can get started here.
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A simple, non-opinionated python terminal menu system WITH TABS
Project description
A flexible, non-opinionated, tabbed menu system to interactively control program flow for terminal-based programs. It’s a class with one sole public method which runs in a while loop as you switch tabs (if you want tabs, that is; you’re free not to have any) or if you enter invalid input, and then returns a string based on the value you selected that you can use to control the outer program flow.
Of course, you can run the class itself in a while loop in the enclosing program, getting menu choice after menu choice returned as you navigate a program.
Installation
pip install pytabby
Meow.
Usage
from pytabby import Menu myconfig = Menu.safe_read_yaml('path/to/yaml') # or Menu.read_json() or just pass a dict in the next step mymenu = Menu(myconfig) result = mymenu.run() if result == 'result1': do_this_interesting_thing() elif result == 'result2': do_this_other_thing() # etc...
See it in action!
- *Why did you make this?
- Well, it was one of those typical GitHub/PyPI scenarios, I wanted a specific thing, so I made a specific thing and then I took >10X the time making it a project so that others can use the thing; maybe some people will find it useful, maybe not. I like running programs in the terminal, and this allowed me to put a bunch of utilities like duplicate file finders and bulk file renamers all under one umbrella. If you prefer GUIs, there are plenty of simple wrappers out there,
- Why can’t I return handlers?
- Out of scope for this project at this time, but it’s on the Wish List. For now, the Menu instance just returns strings which the outer closure can then use to control program flow, including defining handlers using control flow/if statement based on the string returned by Menu.run().
- Why are my return values coming in/out strings?
- To keep things simple, all input and output (return) values are converted to string. So if you have config['tabs'][0]['items][0]['item_returns'] = 1, the return value will be ‘1’.
- Why do ‘items’ have both ‘item_choice_displayed’ and ‘item_inputs’ keys?
- To keep things flexible, you don’t have to display exactly what you’ll accept as input. For example, you could display ‘yes/no’ as the suggested answers to a yes or no question, but actually accept [‘y’, ‘n’, ‘yes’, ‘no’], etc.
- I have ‘case_sensitive’ = False, but my return value is still uppercase.
- case_sensitive only affects inputs, not outputs
- What’s up with passing a dict with the tab name as a message to Menu.run()?
- The message might be different depending on the tab, and run() only exits when it returns a value when given a valid item input. It changes tabs in a loop, keeping that implementation detail abstracted away from the user, as is right.
Dependencies
- PyYAML>=5.1
- schema>=0.7.0
Wish List:
- a way to dynamically silence (“grey out”, if this were a GUI menu system) certain menu items, which may be desired during program flow, probably by passing a list of silenced tab names and return values
- have an option to accept single keypresses instead of multiple keys and ENTER with the input() function, using msvcrt package in Windows or tty and termios in Mac/Linux. (This will make coverage platform- dependent, so it will have to be cumulative on travis and appveyor)
Photo Credit
Erik-Jan Leusink via Unsplash
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.
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The term Ajax was invented to describe the technologies that provide background request-response between a web server and client browser. With Ajax, web applications can retrieve data from the server in the background, essentially preloading information that is revealed in response to a user gesture and giving the impression of a more responsive web page. Although the data appears to be downloaded asynchronously, the server responds to client requests — typically through the use of the
XMLHttpRequest object.
Web protocols require that servers respond to browser requests. Ajax falls short for multi-user, interactive pages because one user won't see changes other users make until the browser sends a request. In order for a server to push data to a browser asynchronously, some design workarounds are required. These design strategies are broadly described by the term Reverse Ajax.
One strategy is to use browser polling, in which the browser makes a request of the server every few seconds. Another strategy, known as piggybacking, delays a server's page update until the next request is received from the browser, at which time the server sends the pending update along with the response.
A third strategy, and the one used in the example application presented in this article, is to design with long-lived HTTP connections between the browser and server. With this strategy, a browser does not poll the server for updates; instead, the server has an open line of communication it can use to send data to the browser asynchronously. Such connections reduce the latency with which messages are passed to the server. This technique is known as Comet — a play on words that can be appreciated by users of household cleansers.
A RESTful web service conforms to Representational State transfer (REST) architectural style. The style is characterized by a simple interface that transmits domain-specific data over HTTP without an additional messaging layer such as SOAP.
The example application discussed in this article presents a photo slideshow that can be controlled by multiple users. Actions of one user affect the pages seen by other users. The application provides a chat feature that enables users to comment on photos and let other users see the comments.
The example application incorporates the following technologies. All are available for download.
dojox.cometmodule simplifies programming Comet applications.
Comet is a term coined by Alex Russell to describe applications where the server pushes data to the client over a long-lived HTTP connection. Comet uses the persistent connection feature in HTTP/1.1. This feature keeps alive the TCP connection between the server and the browser until an explicit 'close connection' message is sent by one or the other, or until a timeout or network error occurs. The technique enables the server to send a message to the client when an event occurs without waiting for the client to send a request.
Grizzly is an HTTP framework that uses the Java NIO API to provide fast HTTP processing. Grizzly provides long-lived streaming HTTP connections that can be used by Comet, with support built on top of Grizzly's Asynchronous Request Processing (ARP). With Grizzly ARP, each Comet request doesn't monopolize a thread, and the availability of threads permits scalability.
Bayeux is a protocol for routing JSON-encoded events between clients and servers in a publish-subscribe model. Grizzly provides an implementation of Bayeux, which makes it easy to build Comet applications with
dojox.comet. To build your application, configure GlassFish for Comet and configure your web application's
web.xml file for the Grizzly Bayeux servlet. You can then use the
dojox
cometd publish and subscribe methods to send and receive Comet events. These techniques are described in more detail in the description of the application.
To run the example application, you need to download and install the code and necessary software tools. The sample code is available as a NetBeans project. You can build and run the sample code using the NetBeans IDE. This example uses NetBeans IDE 6.5 Beta — at the time you read this article, the final release version may be available. The example has also been shown to work with NetBeans IDE 6.1.
redline to the GlassFish
domain.xmlfile in the
glassfish-v2ur2\domains\domain1\configdirectory:
slideshow, and can be found in the directory where you extracted the example files. For example, if you extracted the contents of the zip file to the root directory
C:\on a Windows machine, then your newly created directory would be
C:\slideshow.
cometslideshow. A New Database Connection window opens. Click OK to accept the default settings.
cometslideshowdriver and choose Connect from the menu.
cometslideshowdriver and choose Execute Command from the menu. A SQL command window opens.
slides.sqlfile in the
slideshowdirectory and paste the contents into the SQL command window.
slideshow/setup/sun-resources.xmlfile and verify that the property values it specifies match those of the
cometslideshowdatabase you created. Edit the property values as necessary.
slideshownode in the Projects window.). Open another browser window and set its URL to, then enter a name and click the Join button in both browser windows. Now, when you click the Next Slide button in one browser window, you'll see that both browsers are updated with the next slide.
In the following discussion, code in the examples is sometimes highlighted in color to facilitate the explanation. The discussion explains the techniques used to incorporate the technologies described earlier during application development. Headings for each code sample identify the file from which it was taken.
To use Comet and the Grizzly Comet Framework with GlassFish, simply add the line shown in
red to the GlassFish configuration
domain.xml file.
To enable Bayeux on GlassFish, add the line shown in bold text to your Web application's
web.xml file:
Package your
war file and deploy it on GlassFish. Then, every request sent to your
war file's
context-path /cometd/ will be serviced by the Grizzly Bayeux runtime.
The Comet chat feature used in the example application was adapted from an example originally written by Greg Wilkins. As adapted, the feature enables a slideshow presentation to be shared among subscribed clients. Figure 2 shows the Comet Slideshow page, which allows the users to share a slideshow and chat at the same time.
There are three ways to install Dojo, which you can read about in the book of Dojo. A quick and easy way to use Dojo with the NetBeans IDE is to download the JavaScript libraries from dojotoolkit.org. You would then perform the following steps. These steps have already been done for the example project so you do not have to download Dojo in order to run the example.
.../web.
dojo-release-1.1.1/to
src/, which will give you the NetBeans project structure shown in the following figure.
To load Dojo into your application, put the relative path to the
dojo.js file in a
script element in the head section of your HTML page, as shown here:
This script element loads the base Dojo script that gives you access to all the Dojo functionality. The rest of the JavaScript code for this application is in the file
chat.js. Note that NetBeans IDE 6.5 Beta has a very capable JavaScript editor, shown below editing the
chat.js file:
In
chat.js, the application uses the
dojo.require function (similar to the
import directive in Java) to specify which Dojo modules to load.
Upon loading the Slideshow application, a user can enter a username and join a slideshow session, as shown in Figure 3.
When a user clicks the Join button, the
join JavaScript function is called. In the
join function, the call to
dojox.cometd.init initializes a connection to the given Comet server — in this case with the GlassFish Grizzly Bayeux servlet. Note that
/cometd/* is the URL-pattern for the Grizzly Cometd servlet configured in the
web.xml file for the application.
The
dojox.cometd.subscribe line subscribes the
chatCallback callback function to the
/chat/demo channel. Whenever a message is sent to the
/chat/demo channel, the
chatCallback function is called. The
dojox.cometd.publish line publishes a message that the user whose name was entered with the Join button has joined the
/chat/demo channel. All subscribers to the
/chat/demo channel receive the message.
When the user clicks the Next Slide button, a JavaScript function is called that publishes the URL for the next slide, as shown in Figure 4.
The JavaScript function that is called when the user clicks the Next Slide button is shown in the following code sample. This function calls
room.next, which passes the URL for the next slide. The function then increments the index for the next slide. The URLs for the slides are stored in the
slideUrls array, which is loaded at initialization in the
room.loadSlides() function. The function also calls the
slides JAX-RS REST Web service, which is discussed later.
The function
room.next, shown in the following code sample, calls
dojox.cometd.publish to publish the next slide URL (which it receives as an input argument) to the
/chat/demo channel. All subscribers to the
/chat/demo channel receive this message.
When a message is published to a Bayeux channel on the server, it is delivered to all clients subscribed to that channel — in this case, to the
/chat/demo channel.
In the
room.join function described earlier,
dojox.cometd.subscribe("/chat/demo", room, "chatCallback") was called to subscribe the
chatCallback callback function to the
/chat/demo channel. The
chatCallback function, shown in the following code sample, is called with the published message as an input argument. The
chatCallback function updates the browser page by setting the
slide dom element
innerHTML to an HTML
img tag with the slide URL from the published message
"<img src='" + slideUrl + "'/>". This message updates the browser page with the image that corresponds to the slide URL that was published.
The
dojo.addOnLoad function enables you to call a function after a page has loaded and after Dojo has finished its initialization. This application uses
dojo.addOnLoad to call the
init function. The
init function calls the
loadSlides function, which in turn calls the
slides JAX-RS web service and saves the results in the
slideUrls object, as shown in the following code sample.
The
loadTable function calls
dojo.xhrGet to make an
XMLHttpRequest request to the
slides JAX-RS web service that is specified by the
url parameter. When the response from web service is returned, the callback function
handleResponse specified by the
load parameter is called, and the response is passed to the callback function in the
responseObject.
The
handleAs parameter specifies the response data type. Specifically,
handleAs: "json" identifies the type of the returned data as JSON (JavaScript object notation). In the
handleResponse callback function, the slides data (
responseObject.slides.slide) that is returned from the
slides JAX-RS web service is saved in the
slideUrls object. The following example shows a JSON response from the
slides JAX-RS web service.
The
dojo.xhrGet url parameter references the URI
resources/slides/ for the
slides RESTful web service. The
slides RESTful web service was generated using NetBeans, as explained in the tutorial Generating RESTful Web Services from Entity Classes. Beginning with NetBeans 6.1, you can generate JPA entity classes from database tables. You can then generate RESTful web services from these entity classes and test the web services in a browser interface. The
slides RESTful web service was generated from the
slide database table.
The code shown in the following sample is a snippet from the
SlidesResource.java class that was generated by the NetBeans "generate RESTful web services from entity classes" feature.
The
SlidesResource class represents a list of slides. The
SlidesResource get method returns a list of Slide objects in JSON format.
@Pathidentifies the URI path for the resource. For the resource
SlidesResource, the URI path is
/
slides
/.
@GETspecifies the
getmethod that supports the HTTP GET method.
@ProduceMimespecifies the MIME types that a method can produce. Here, the annotation specifies a
getmethod that returns a
JSONArrayobject. The
SlidesConverterclass is a JAXB annotated class that is used to marshal a list of Slide objects into XML or JSON format. The
getEntitiesmethod returns a list of Slide entity objects and is explained below.
@QueryParamspecifies input parameters for methods. When the method is invoked, the input value is injected into the corresponding input argument.
@DefaultValuespecifies a default value for an argument if no input value is given.
The following is an example of an HTTP request for this Web Service.
The following code is an example of an HTTP response for this web service.
The
SlidesConverter class is a JAXB annotated class, used to marshal a list of Slide objects into XML or JSON format. A snippet of the
SlidesConverter class is shown in the following code sample, with annotations shown in
blue .
The
SlidesResource
getEntities method uses the Java Persistence API
Query object to return a list of
slides.
The Java Persistence Query APIs are used to create and execute queries that can return a list of results. The JPA Query interface provides support for pagination via the
setFirstResult() and
setMaxResults() methods:
query.setMaxResults(int maxResult) sets the maximum number of results to retrieve, and
query.setFirstResult(int startPosition) sets the position of the first result to retrieve.
The following code shows the
Slide entity class, which maps to the CUSTOMER table that stores the slide instances. This is a typical Java Persistence entity object. There are two requirements for an entity:
@Entityannotation.
@Idannotation.
Because the fields
id,
name,
description, and so on, are basic mappings from the object fields that identify columns of the same name in the database table, they don't have to be annotated.
For more information on NetBeans and JPA, see the tutorial Java Persistence in the Java EE 5 Platform.
The example application demonstrates the use of Dojo, Comet, Bayeux, and a RESTful Web Service, coded using JAX-RS: Java API for RESTful Web Services (JSR-311), JPA, running on the GlassFish application server with Grizzly and MySQL.
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What Are Partial Types in C#?
What Are Partial Types in C#?
Partial types are another construct that Microsoft has proposed be added to the C# language in order to allow a single class to be defined in more than one file. Although it is recommended that a class be stored in a single source file, sometimes it is just not practical. While you can rewrite a class to inherit some of the code from a subclass, this also is not always practical.
Partial types resolve this by allowing multiple files to be used to declare a single class. When compiled, the classes can be combined so that a single class is created. One of the most notable benefits of using partial types is when you also use a code generator. If you use a tool to generate some of your code, you can use partial types to combine the generated code with your own additions to the class. You can keep both pieces in separate files. You won't have to worry about inadvertently changing some of the generated code.
Implementing Partial Types
Partial:
Listing 1—FileOne.cs—Not a Complete Listing
public class partial MyClass{ // Class stuff... public void FunctionInMyClass() { // Logic... } // more stuff...}
Listing 2—FileTwo.cs—Not a Complete Listing
public class partial MyClass{ // Class stuff... public void AntherFunctionInMyClass() { // Logic... } // more stuff...}
When these listings are compiled together, the logic is combined into a single class as though a single listing were being used.
About the Author
Bradley Jones is the Executive Editor for Earthweb's Software Development channel, which includes sites such as Developer.com, Codeguru, and Gamelan. He is also the author of the book Sams Teach Yourself the C# Language in 21 Days.
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Programmers frequently use console.log to record errors or other informational messages in their Angular applications. Although this is fine while debugging your application, it's not a best practice for production applications. As Angular is all about services, it's a better idea to create a logging service that you can call from other services and components. In this logging service, you can still call console.log, but you can also modify the service later to record messages to store them in local storage or a database table via the Web API.
In this article, you'll build up the logging service in a series of steps. First, you create a simple log service class to log messages using console.log(). Next, you add some logging levels so you can report on debug, warning, error, and other types of log messages. Then you create a generic logging service class to call other classes to log to the console, local storage, and a Web API. Finally, you create a log publishing service that reads a JSON file to choose which log service classes to use.
A Simple Logging Service
To get started, create a very simple logging service that only logs to the console. The point here is to replace all of your console.log statements in your Angular application with calls to a service. Bring up an existing Angular application or create a new one. If you don't already have one, add a folder named shared under the \src\app folder. Create a new TypeScript file named log.service.ts. Add the code shown in the following snippet.
import { Injectable } from '@angular/core'; @Injectable() export class LogService { log(msg: any) { console.log(new Date() + ": " + JSON.stringify(msg)); } }
This code creates an injectable service that can be created by Angular and injected into any of your Angular classes. The log() method accepts a message that can be any type. A new date is created so each message can be logged to the console with the date and time attached to it. The date/time is not that important when just logging to the console, but once you start logging to local storage or to a database, you want the date/time attached so you know when the log messages was created. Notice the use of JSON.stringify around the msg parameter. This allows you to pass an object and it can be logged as a string.
For the purpose of following along with this article, create a new folder called \log-test and add a log-test.component.html page. Add a button to test the logging service.
<button (click)="testLog()"> Log Test </button>
Create a log-test.component.ts TypeScript file and add the code shown in Listing 1 to respond to the button click event.
Add a logger variable to your constructor so Angular can inject this service into this component. Notice that in the testLog() method you now call the this.logger.log() instead of console.log(). The result is the same (See Figure 1) in that the message appears in the console window. However, you've now given yourself the flexibility to log this message to local storage, to a database table, to the console, or to all three. And, the best part is, you don't have to change any code in your application, other than the code in the LogService class. To use this service in your Angular application, you need to import it in your app.module.ts file. Also import the LogTestComponent you created as well.
import { LogService } from './shared/log.service'; import { LogTestComponent } from './log-test/log-test.component';
Add the LogService to the providers property in the @NgModule statement. Add the LogTestComponent class to the declarations property, as shown in the code snippet below.
@NgModule({ imports: [BrowserModule], declarations: [AppComponent, LogTestComponent], bootstrap: [AppComponent], providers: [LogService] }) export class AppModule { }
Add the
Different Types of Logging
There are times when you might want only certain types of logging turned on when running your application. Many logging systems in other languages allow you to log debug messages, informational messages, warning messages, etc. Add this same ability to your LogService class by adding an enumeration and a property that you can set to control which messages to display. First, add a LogLevel enumeration in the log.service.ts file to keep track of what kind of logging to perform. Add this enumeration just after the import statement within the log.service.ts the file. Don't add it within the LogService class.
export enum LogLevel { All = 0, Debug = 1, Info = 2, Warn = 3, Error = 4, Fatal = 5, Off = 6 }
Add a property to the LogService class named level that's of the type LogLevel. Default the value to the All enumeration. While you are adding properties, add a Boolean property named logWithDate to specify whether you wish to add the date/time to the front of your messages or not.
level: LogLevel = LogLevel.All; logWithDate: boolean = true;
Instead of having to set the level property prior to calling your logger.log() method, add the new methods debug, info, warn, error, and fatal to the LogService class (Listing 2). Each one of these methods calls a writeToLog() method passing in the message, the appropriate enumeration value and an optional parameter array. Delete the log() method you wrote previously and replace that one method with all the methods from Listing 2.
The optional parameter array means you can pass any parameters you want to be logged. For example, any of the following calls are valid.
this.logger.log("Test 2 Parameters", "Paul", "Smith"); this.logger.debug("Test Mixed Parameters", true, false, "Paul", "Smith"); let values = ["1", "Paul", "Smith"]; this.logger.warn("Test String and Array", "Some log entry", values);
The writeLog() method, Listing 3, checks the level passed by one of the methods against the value set in the level property. This level property is checked in the shouldLog() method. Both of these methods should now be added to your LogService class.
The shouldLog() method determines if logging should occur based on the level property set in the LogService class. This service is created as a singleton by Angular, so once this level property is set, it remains that value until you change it in your application. The shouldLog() checks the parameter passed in against the level property set in the LogService class. If the level passed in is greater than or equal to the level property, and logging is not turned off, then a true value is returned from this method. A true return value tells the writeToLog() method to log the message.
private shouldLog(level: LogLevel): boolean { let ret: boolean = false; if ((level >= this.level && level !== LogLevel.Off) || this.level === LogLevel.All) { ret = true; } return ret; }
There's one more method call in the writeToLog() method called formatParams(). This method is used to create a comma-delimited list of the parameter array. If all parameters in the array are simple data types and not an object, then the local variable named ret is returned after the join() method is used to create a comma-delimited list from the array. If there is one object, loop through each of the items in the params array and build the ret variable using the JSON.stringify() method to convert each parameter to a string, and then append a comma after each.
private formatParams(params: any[]): string { let ret: string = params.join(","); // Is there at least one object in the array? if (params.some(p => typeof p == "object")) { ret = ""; // Build comma-delimited string for (let item of params) { ret += JSON.stringify(item) + ","; } } return ret; }
Create Log Entry Class
Instead of building a string of the log information, and formatting the parameters in the writeToLog() method, create a class named LogEntry to do all this for you. Place this new class within the log.service.ts file. The LogEntry class, shown in Listing 4, has properties for the date of the log entry, the message to log, the log level, an array of extra info to log, and a Boolean you set to specify to include the date with the log message.
The buildLogString() method is similar to what you wrote in the writeToLog() method earlier. This method gathers the values from the properties of this class and returns them in one long string that can be used to output to the console window. Remove the formatParams() method from the LogService class after you've built the LogEntry class. You're going to use this LogEntry class from each of the different logging classes you build in the rest of this article.
Now that you have this LogEntry class built, and have removed the formatParams() from the LogService class, rewrite the writeToLog() method to look like the code below.
private writeToLog(msg: string, level: LogLevel, params: any[]) { if (this.shouldLog(level)) { let entry: LogEntry = new LogEntry(); entry.message = msg; entry.level = level; entry.extraInfo = params; entry.logWithDate = this.logWithDate; console.log(entry.buildLogString()); } }
After modifying the writeToLog() method, rerun the application and you should still see your log messages being displayed in the console window.
Log Publishing System
When logging exceptions, or any kind of message, it's a good idea to write those log entries to different locations in case one of those locations isn't accessible. In this way, you stand a better chance of not losing any messages. To do this, you need to create three different classes for logging. The first publisher is a LogConsole class that logs to the console window. The second publisher is LogLocalStorage to log messages to Web local storage. The third publisher is LogWebApi for calling a Web API to log messages to a backend table in a database.
Instead of hard-coding each of these classes in the LogService class, you're going to create a publishers property (Figure 2), which is an array of an abstract class called LogPublisher. Each of the logging classes you create extends this abstract class.
The LogPublisher class contains one property named location. This property is used to set the key for local storage and the URL for the Web API. This class also needs two methods: log() and clear(). The log() method is overridden in each class that extends LogPublisher and is responsible for performing the logging. The clear() method removes all log entries from the data store.
Add a new TypeScript file named log-publishers.ts to the \shared folder in your project. You're going to need a few import statements at the top of this file. In fact, you're going to add more later, but for now, just add Observable, the Observable of, and LogEntry classes. Write the code shown in the next snippet to create your abstract LogPublisher class.
import { Observable } from 'rxjs/Observable'; import 'rxjs/add/observable/of'; import { LogEntry } from './log.service'; export abstract class LogPublisher { location: string; abstract log(record: LogEntry): Observable<boolean> abstract clear(): Observable<boolean>; }
Now that you have the template for creating each log publishing class, let's start building them.
Log to Console
The first class you create to extend the LogPublisher class writes messages to the console. You're eventually going to remove the call to console.log() from the LogService class you created earlier. LogConsole is a very simple class that displays log data to the console window using console.log(). Add the following code below the LogPublisher class in the log-publisher.ts file.
export class LogConsole extends LogPublisher { log(entry: LogEntry): Observable<boolean> { // Log to console console.log(entry.buildLogString()); return Observable.of(true); } clear(): Observable<boolean> { console.clear(); return Observable.of(true); } }
Notice that the log() method in this class accepts an instance of the LogEntry class. This parameter coming in, named entry, calls the buildLogString() method to create a string of the complete log entry data to be displayed to the console window. Each log() method needs to return an observable of the type Boolean back to the caller. Because nothing can go wrong with logging to the console, just hard-code a True return value.
The clear() method must also be overridden in any class that extends the LogPublisher class. For the console window, call the clear() method to clear all messages published to the console window.
The Log Publishers Service
As you saw in Figure 2, there's a publishers array property in the LogService class. You need to populate this array with instances of LogPublisher classes. The only class you've built so far is LogConsole, but soon you'll build LogLocalStorage and LogWebApi classes too. Instead of building the list of publishers in the LogService class, create another service class to build the list of log publishers. This service class, named LogPublishersService, is responsible for building the array of log publishing classes. This service is passed into the LogService class so the publishers array can be assigned from the LogPublishersService (Figure 3). At first, you're going to just hard-code each of the log classes, but later in this article, you're going to read the list publishers from a JSON file.
The LogPublishersService class (Listing 5) needs to be defined as an injectable service so Angular can inject it into the LogService class. In the constructor of this class, you call a method named buildPublishers(). This method creates each instance of a LogPublisher and adds each instance to the publishers array. For now, just add the code to create new instance of the LogConsole class and push it onto the publishers array.
Update AppModule Class
Like any Angular service, once you create it, you must register it in the app.module.ts file by importing it and adding it to the providers property of the @NgModule. Open app.module.ts and add the import near the top of the file.
import { LogPublishersService } from "./shared/log-publishers.service";
Next, add the service to the providers property in the @NgModule decorator function.
@NgModule({ imports: [BrowserModule, FormsModule, HttpModule], declarations: [AppComponent, LogTestComponent], bootstrap: [AppComponent], providers: [LogService, LogPublishersService] })
Modify the LogService Class
It's now time to modify the LogService class to use this LogPublishersService class. Open the log.service.ts TypeScript file and add two import statements near the top of the file.
import { LogPublisher } from "./log-publishers"; import { LogPublishersService } from "./shared/log-publishers.service";
Add a property named publishers that is an array of LogPublisher types.
publishers: LogPublisher[];
Add a constructor to the LogService class so Angular injects the LogPublishersService. Within this constructor, take the publishers property from the LogPublishersService and assign the contents to the publishers property in the LogService class.
constructor(private publishersService: LogPublishersService) { // Set publishers this.publishers = this.publishersService.publishers; }
Locate the writeToLog() method and remove the following line of code from this method.
console.log(entry.buildLogString());
Where you removed the above line of code, add a for loop to iterate over the list of publishers. Each time through the loop, invoke the log() method of the logger, passing in the LogEntry object. Because the log() method returns an observable, you should subscribe to the result and write the Boolean return value to the console window.
for (let logger of this.publishers) { logger.log(entry) .subscribe(response => console.log(response)); }
Once again, run the application and click the Test Log button to see a log entry written to the console window. You have added a few classes and a service only to publish to the console window; you should be able to see the advantages of this kind of approach. You can now add new LogPublisher classes, add them to the array in the LogPublishersService class, and you're now publishing to an additional location.
Log to Local Storage
The next publisher to add is one that stores an array of LogEntry objects into your Web browser's local storage. Open the log-publishers.ts file and add the code shown in Listing 6 to this file. The LogLocalStorage class needs to set a key value for setting the items into local storage. Use the location property to set the key value to use. In this case, the location is set in the constructor. When you have a constructor in a derived class, you always need to call the super() method in order to invoke the constructor of the base class.
Local storage allows you to store quite a bit of data, so let's add each log entry each time the log() method is called. The setItem() method is used to set a value into local storage. If you call setItem() and pass in a value, any old value in the key location is replaced with the new value. Read the previous values first from local storage using the getItem() method. Parse that into an array of LogEntry objects, or if there was no value stored in that key location, return an empty array. Push the new LogEntry object onto the array, stringify the new array, and place the stringified array into local storage.
One note of caution on local storage; there's a limit set by each browser to how much data can be stored. The limits vary between browsers, and as of this writing, it varies from 2MB to 10MB. You might want to consider writing some additional code in the catch block of the log() method to remove the oldest values from the array prior to storing the new log entry.
The clear() method is used to clear local storage at the specified key location. Call the removeItem() method of the localStorage object to clear all values within this location.
Now that you have your new class to store log entries into local storage, you need to add this to the publishers array. Open the log-publishers.service.ts file and modify the import statement to include your new LogLocalStorage class.
import { LogPublisher, LogConsole, LogLocalStorage } from "./log-publishers";
Modify the buildPublishers() method of the LogPublishersService class to create an instance of the LogLocalStorage class and push it onto the publishers array as shown in the following code.
buildPublishers(): void { // Create instance of LogConsole Class this.publishers.push(new LogConsole()); // Create instance of LogLocalStorage Class this.publishers.push(new LogLocalStorage()); }
You can now re-run the application and you should be logging to both the console window and to local storage. To test this, set a break point in the log() method of the LogLocalStorage class and see if it retrieves the previous values that you logged into local storage.
Log to Web API
The last logging class you are going to create is one to send an instance of the LogEntry class to a Web API method. From this Web API you could then write code to store the log entry into a database table. I'm not going to provide you with a table - I'll leave that to you. I'm using Visual Studio and C# to create my Web API calls, so I'm going to add a C# class to my project that's the same name and has the same properties as the LogEntry class I created in Angular.
public class LogEntry { public DateTime EntryDate { get; set; } public string Message { get; set; } public LogLevel Level { get; set; } public object[] ExtraInfo { get; set; } }
I'm also adding a C# enumeration to my project to map to the TypeScript LoggingLevel enumeration.
public enum LogLevel { All = 0, Debug = 1, Info = 2, Warn = 3, Error = 4, Fatal = 5, Off = 6 }
Finally, I'm going to add a Web API controller class (Listing 7) to my project. This class has one method at this point to allow Angular to post the LogEntry record to this method. It's in this Post() method that you write the code to store the log data into a database table. For purposes of this article, I'm just going to return a result of OK (true) back to the caller.
Now that you have the Web API classes created, you can go back to the log-publishers.ts file and add some import statements for calling a Web API. Add the following import statements near the top of this file.
import { Http, Response, Headers, RequestOptions } from '@angular/http'; import 'rxjs/add/operator/map'; import 'rxjs/add/operator/catch'; import 'rxjs/add/observable/throw';
Add the LogWebApi class shown in Listing 8 at the bottom of the log-publishers.ts file. The constructor for this class is very similar to the one you wrote for the LogLocalStorage class. You do need to include the HTTP service as you're going to need this to call the Web API. You also must call super() to execute the constructor of the base class. Finally, set the location property to the URL of the Web API call.
The log() method accepts a LogEntry object that's sent to the Web API method. Because you're performing a POST to the Web API, you need to create the appropriate headers to specify the content type you're sending as application/json. The post() method on the Angular HTTP service is called to pass the LogEntry object to the Web API class you created.
You also need a clear() method in this class to override the abstract method in the base class. In order to keep the length of this article shorter, I'm not showing how to do clear log entries, but it's similar to the log() method. You call a Web API method that writes the appropriate SQL to delete all rows from your log table in your database.
Open the log-publishers.service.ts file and modify the import statement to include your new LogWebApi class.
import { LogPublisher, LogConsole, LogLocalStorage, LogWebApi } from "./log-publishers";
Open your log-publishers.service.ts file and add an import for the HTTP service near the top of the file.
import { Http } from '@angular/http';
Next, add the HTTP service to the constructor of this class.
constructor(private http: Http) { // Build publishers arrays this.buildPublishers(); }
Finally, in the buildPublishers() method, create a new instance of the LogWebApi class and pass in the HTTP service as shown in the code below.
buildPublishers(): void { // Create instance of LogConsole Class this.publishers.push(new LogConsole()); // Create instance of LogLocalStorage Class this.publishers.push(new LogLocalStorage()); // Create instance of LogWebApi Class this.publishers.push( new LogWebApi(this.http)); }
You need to register the HTTP service with your AppModule. Open app.module.ts and add the following import near the top of this file.
import { HttpModule } from '@angular/http';
Add the HttpModule to the imports property in the @NgModule() function decorator.
imports: [BrowserModule, HttpModule],
Now that you have this new publisher added to the array, you should be able to run your logging application, and when you click on the Log Test button, you should see that it's making the call to your Web API method.
Read Publishers from JSON File
Open the log-publishers.ts file and add a new class called LogPublisherConfig. This class is going to hold the individual objects read from a JSON file you see in Listing 9.
class LogPublisherConfig { loggerName: string; loggerLocation: string; isActive: boolean; }
Build the JSON file by adding an \assets folder underneath the \src\app folder. Add a JSON file called log-publishers.json in the \assets folder and add the code from Listing 9. Each of the object literals in this JSON array relate to one of the classes you created for logging to the console, local storage, and the Web API.
Add a few more import statements to your log-publishers.service.ts file.
import { Observable } from 'rxjs/Observable'; import 'rxjs/add/operator/map'; import 'rxjs/add/operator/catch'; import 'rxjs/add/observable/throw';
Add a constant just after these imports, to point to this file.
const PUBLISHERS_FILE = "/src/app/assets/log-publishers.json";
In the LogPublishersService class, add a new method named handleErrors (Listing 10) to take care of any errors that might happen during any HTTP service calls. Also, in the LogPublishersService class, create a new method to read the data from this JSON file. Let's call this method getLoggers(). Because you already injected the HTTP service into this class, you can use this service to read from the JSON file.
getLoggers(): Observable<LogPublisherConfig[]> { return this.http.get(PUBLISHERS_FILE) .map(response => response.json()) .catch(this.handleErrors); }
Now that you have this method to return the array from this file, modify the buildPublishers() method to subscribe to this Observable array of LogPublisherConfig object. The new code for the buildPublishers() method is shown in Listing 11.
The buildPublishers() method calls the getLoggers() method and subscribes to the output from this method. The output is an array of LogPublisherConfig objects. The array of configuration objects is filtered to only loop through those that have their isActive property set to a True value. For each iteration through the loop, check the loggerName property and compare that value with those listed in each case statement. If a match is found, a new instance of the corresponding LogPublisher class is created. The loggerLocation property is set to the location property of each LogPublisher class. The newly instantiated publisher object is then added to the publishers array property. As all of this happens in the constructor of this service class; the publishers array is already set to the list of publishers to use by the time it is injected into the LogService class. You should be able to run the Angular application and click on the Log Test button and see the log messages published to all publishers marked as isActive in the JSON file.
Summary
It's always a best practice to log messages as you move throughout your Angular applications. Exceptions should always be logged, but you may also wish to log the debug, warning, and informational messages as well. Creating a flexible logging system like the one presented in this article assists with this best practice. Using a configuration JSON file to store which publishers you wish to log to saves having to hard-code publishers within your log service class.
Listing 1: The LogTestComponent to test the LogService class
import { Component } from "@angular/core"; import { LogService } from '../shared/log.service'; @Component({ selector: "log-test", templateUrl: "./log-test.component.html" }) export class LogTestComponent { constructor(private logger: LogService) { } testLog(): void { this.logger.log("Test the log() Method"); } }
Listing 2: Add methods to your LogService class to write different kinds of messages
debug(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.Debug, optionalParams); } info(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.Info, optionalParams); } warn(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.Warn, optionalParams); } error(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.Error, optionalParams); } fatal(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.Fatal, optionalParams); } log(msg: string, ...optionalParams: any[]) { this.writeToLog(msg, LogLevel.All, optionalParams); }
Listing 3: The writeToLog() method creates the message to write into your log
private writeToLog(msg: string, level: LogLevel, params: any[]) { if (this.shouldLog(level)) { let value: string = ""; // Build log string if (this.logWithDate) { value = new Date() + " - "; } value += "Type: " + LogLevel[this.level]; value += " - Message: " + msg; if (params.length) { value += " - Extra Info: " + this.formatParams(params); } // Log the value console.log(value); } }
Listing 4: Create a LogEntry class to make creating log messages easier
export class LogEntry { // Public Properties entryDate: Date = new Date(); message: string = ""; level: LogLevel = LogLevel.Debug; extraInfo: any[] = []; logWithDate: boolean = true; buildLogString(): string { let ret: string = ""; if (this.logWithDate) { ret = new Date() + " - "; } ret += "Type: " + LogLevel[this.level]; ret += " - Message: " + this.message; if (this.extraInfo.length) { ret += " - Extra Info: " + this.formatParams(this.extraInfo); } return ret; } private formatParams(params: any[]): string { let ret: string = params.join(","); // Is there at least one object in the array? if (params.some(p => typeof p == "object")) { ret = ""; // Build comma-delimited string for (let item of params) { ret += JSON.stringify(item) + ","; } } return ret; } }
Listing 5: The LogPublishersService is responsible for creating a list of publishing objects
import { Injectable } from '@angular/core'; import { LogPublisher, LogConsole } from "./log-publishers"; @Injectable() export class LogPublishersService { constructor() { // Build publishers arrays this.buildPublishers(); } // Public properties publishers: LogPublisher[] = []; // Build publishers array buildPublishers(): void { // Create instance of LogConsole Class this.publishers.push(new LogConsole()); } }
Listing 6: Create a LogLocalStorageService class to store messages into local storage
export class LogLocalStorage extends LogPublisher { constructor() { // Must call super() from derived classes super(); // Set location this.location = "logging"; } // Append log entry to local storage log(entry: LogEntry): Observable<boolean> { let ret: boolean = false; let values: LogEntry[]; try { // Get previous values from local storage values = JSON.parse( localStorage.getItem(this.location)) || []; // Add new log entry to array values.push(entry); // Store array into local storage localStorage.setItem(this.location, JSON.stringify(values)); // Set return value ret = true; } catch (ex) { // Display error in console console.log(ex); } return Observable.of(ret); } // Clear all log entries from local storage clear(): Observable<boolean> { localStorage.removeItem(this.location); return Observable.of(true); } }
Listing 7: The LogController allows you to store log entries via a Web API call
public class LogController : ApiController { // POST api/<controller> [HttpPost] public IHttpActionResult Post( [FromBody]LogEntry value) { IHttpActionResult ret; // TODO: Write code to store logging // data in a database table // Return OK for now ret = Ok(true); return ret; } }
Listing 8: Create a LogWebApiService class to call a Web API for tracking log messages
export class LogWebApi extends LogPublisher { constructor(private http: Http) { // Must call super() from derived classes super(); // Set location this.location = "/api/log"; } // Add log entry to back end data store log(entry: LogEntry): Observable<boolean> { let headers = new Headers( { 'Content-Type': 'application/json' }); let options = new RequestOptions({ headers: headers }); return this.http.post(this.location, entry, options) .map(response => response.json()) .catch(this.handleErrors); } // Clear all log entries from local storage clear(): Observable<boolean> { // TODO: Call Web API to clear all values return Observable.of(true); } private handleErrors(error: any): Observable<any> { let errors: string[] = []; let msg: string = ""; msg = "Status: " + error.status; msg += " - Status Text: " + error.statusText; if (error.json()) { msg += " - Exception Message: " + error.json().exceptionMessage; } errors.push(msg); console.error('An error occurred', errors); return Observable.throw(errors); } }
Listing 9: Create a LogLocalStorageService class to store messages into local storage
[ { "loggerName": "console", "loggerLocation": "", "isActive": true }, { "loggerName": "localstorage", "loggerLocation": "logging", "isActive": true }, { "loggerName": "webapi", "loggerLocation": "/api/log", "isActive": true } ]
Listing 10: You always should have a method to handle errors when using the HTTP service
private handleErrors(error: any): Observable<any> { let errors: string[] = []; let msg: string = ""; msg = "Status: " + error.status; msg += " - Status Text: " + error.statusText; if (error.json()) { msg += " - Exception Message: " + error.json().exceptionMessage; } errors.push(msg); console.error('An error occurred', errors); return Observable.throw(errors); }
Listing 11: Create your array of publishers by reading the values from a JSON file
buildPublishers(): void { let logPub: LogPublisher; this.getLoggers().subscribe(response => { for (let pub of response.filter(p => p.isActive)) { switch (pub.loggerName.toLowerCase()) { case "console": logPub = new LogConsole(); break; case "localstorage": logPub = new LogLocalStorage(); break; case "webapi": logPub = new LogWebApi(this.http); break; } // Set location of logging logPub.location = pub.loggerLocation; // Add publisher to array this.publishers.push(logPub); } }); }
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On Tue, Mar 21, 2006 at 05:54:09PM -0400, Felipe Sateler wrote: > Done. But checkinstall doesn't need it, right? You should probably drop that Depends .. You want to have Replaces+Conflicts, though. You probably also want to add Provides, or a dummy package with the name of the old Debian package which is now included in the new package, to force the new package to be installed. > >> /usr/doc/ is now a policy violation; documentation must live in /usr/share/doc/. >. That makes sense to me too; /usr/share/installwatch smells like namespace polution, and asks for confusion if not collision someday. Justin
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Including the DirectX SDK libraries into your Visual C++ game project
1 min read
If you are new to DirectX game programming, you might have come across this pitfall:
You added the DirectX header to your main file and it didn’t compile because the files couldn’t be found.
#include <d3d11.h> #include <d3dx11.h> #include <d3dx10.h>
Fortunately, solving this problem is relatively straightforward.
Downloading the DirectX SDK
You will need the DirectX SDK Libraries from Microsoft. These contain the aforementioned header files and libraries. Download the latest DirectX SDK from here. When the download is complete, proceed by installing the DirectX SDK. Make sure you remember the installation location as you will need this later.
Installing the DirectX SDK
Add references to your project settings
In order to tell Visual Studio that your game requires DirectX, you will have to add the DirectX libraries and header files to your project.
- Open your project setting
- Navigate to VC++ Directories
- On the right, select Includepaths
- A new window will open, that lets you new include paths. Add a new include path by hitting the New Row button in the top right.
- Now you will have to navigate to your DirectX SDK installation directory and select the Include folder.
Do the same for the library path and you project should compile properly.29 Sep 2011
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Sasa Zivkov wrote:
>
>)
I agree, but one thing I do not understand is the following:
How can one decribe looping in HTML without some "loop code".
Does the PHPLib "comment thing" solve this problem?
<table>
<!-- BEGIN row -->
<tr>
<td>{NAME}</td> <td>{EMAIL}</td>
<tr>
<!-- END row -->
</table>
although I prefer
<table>
<!-- BEGIN row -->
<tr>
<td>%[name]</td> <td>%[email]</td>
<tr>
<!-- END row -->
</table>
or even
<table>
<!-- BEGIN row -->
<tr>
<td>[name]</td> <td>[email]</td>
<tr>
<!-- END row -->
</table>
maybe even:
<table>
<!-- BEGIN [row] -->
<tr>
<td>[name]</td> <td>[email]</td>
<tr>
<!-- END [row] -->
</table>
or
<table>
<!-- BEGIN %[row] -->
<tr>
<td>%[name]</td> <td>%[email]</td>
<tr>
<!-- END %[row] -->
</table>
As far as I can see there is template code from 3 people
on this list which appeared in the last weeks.
Quite confusing, but nevertheless very interesting.
Also "Zope Page Templates" could be yet another approach..
--
Tom Schwaller
On Fri, Apr 06, 2001 at 03:28:31PM -0000, Sasa Zivkov wrote:
> What Template System Should Be and What Template System Should Not Be
Oh, so you DID write about what the template system should not be.
I guess we're crossing in the mail.
> we want programers to write the code and we want
> designers to make HTML.
Yes, the purpose is to separate logic from presentation, so that one can
be changed (or completely replaced) without affecting the other.
I have already ported three personal sites from HTML to Zope to PHP (ASP
style) and am now putting them into Webware. Changing the templates is
the most time-consuming part by far because of the assumptions built
into the templates about the environment it's running in. Meanwhile at
work we have made a site () using
PHPLib's template class, and it is a much better model. If we were
someday to switch this site to Webware, I could just drop in the
templates as is. What a glorious thought!
> If we start to make a template system where somebody can actually put
> some logic (loops for example) into the template, or where the
> template knows something about the code (method or function name for
> example) then we are building a new language.
Hello, DTML..
--
-Mike (Iron) Orr, iron@... (if mail problems: mso@...) English * Esperanto * Russkiy * Deutsch * Espan~ol
Some time ago, I posted this extremly small template class, that is modeled
like FastTemplate (php). See
I worked with it since and it does most things I want it to do.
Anyway, I thing we should use the %(var)s syntax instead of {var}.
This will show up in any html Browser or design tool just as normal text and
makes the use so much easier in python.
This FastTemplate approach seem to get quite messy when a certain number of
templates is exceeded. I just forget after a while, what a specific template
is for :-(
What is your experience with the PHPLib approach?
I strongly fell that we should have at least three different methods
available in the end:
1. something easy like FastTemplate
2. something on the middle ground like PHPLib
and
3. the XML approach that was earlier mentioned in this thread
just my two cents
--stephan
>
>
>_______________________________________________
>Webware-discuss mailing list
>Webware-discuss@...
>
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at.
Tavis Rudd wrote:
>
> Here's the final code for my template-filling packages
>
> NameMapper v1.6
> ==============
> * my extended implementation of NamedValueAccess
> --standalone
>
> TemplateFiller v1.5
> ==============
> * a very flexible template filler that supports all the
> features of NameMapper and plus namespace cascading
> * will replace varNames in %()s, %()d, or %()d plus any
> custom delimeters of your choice, defaults to %[]
> -- needs on NameMapper v1.6
>
> SkeletonPage v1.3
> ==============
> * an example of how to implement TemplateFiller in a
> complete, easy to use, templating framework
> -- needs on NameMapper v1.6 and TemplateFiller v1.5
>
> Yet to come:
> ==========
> - a servlet factory that implements the idea in my last
cool, I like your approach.
I think there's a small typo in SkeletonPage in
the Default class
def currentYr(self):
return time.strftime("%Y",time.localtime())
should be:
def currentYr(self):
return time.strftime("%Y",time.localtime(time.time()))
One thing I probably missed is a small example how
to do looping or is this not covered in your approach.
hope you get along with the ServletFactory code soon,
so peple can experiment with it in an easy fashion..
--
Tom Schwaller
On Fri, Apr 06, 2001 at 01:05:30PM -0000, Sasa Zivkov wrote:
> I think that we should somehow join our efforts to make a good
> template based solution compatible with Webware's approach.
Definitely. Having one great package would be better than three OK
packages where choosing any one means losing the advantages of the
other two.
Right now I'm still trying to get my head around Travis' implementation.
I think somehow my class could fit as a wrapper around his, which would
gain the NameMapper access. What I don't see is how his package handles
blocks or nested templates. Perhaps I'm missing something, or perhaps
that belongs on a level outside his classes.
Travis, can you take the test() function from my module and show how you
would implement the equivalent using your classes? This would give an
example of how to do blocks.
If we make a specification, the motto should be "flexibility". An
extensible back end that alternative front ends can be latched onto.
Thus, while I'm really attached to my block(), keep() and kill()
methods, and the ability to do nested templates in one umbrella object,
maybe somebody else isn't.
There's two ways to handle blocks and nested templates. One is PHPLib's
approach, which puts everything in a flat namespace. This is simple but
it means you sometimes have to be creative with names to avoid name
collision. The other approach would be to extract the block to a new
template instance. Nested templates could also be handled this way.
This could work under a NameMapper scenario if the template's __str__
method did the equivalent of of Travis's fill(). ...which may not be
a bad idea in any case.
We should also not lock in certain opening and closing delimeters.
Nor should we require the two to be the same length (which PHPLib does).
Travis' implementation of a regex with a group to match the placeholders
seems like the best. I would suggest replacing regex1 ( %[key] ) and
regex2 ( %(key)s ) with a list of regexes which would be tried in
order. In particular, {key} must be allowed even if it isn't enabled
by default.
We also need to allow "escaping" the opening delimeter so it can be used
as a literal. This can be accomplished by writing a regex which doesn't
match the escaped syntax. For instance, the "%" operator matches
%(key)s but not %%(key)s.
The expressions used and other configuration values should be class
attributes. It looks like Travis' implementation makes you pass these
to every constructor. Presumably the user consistently use the same
configuration for all templates in an application.
> - what template system should be and what template system should not be
I didn't see anything in your description about what a template system
should not be.
> - make a proposal on how to implement template system that will be
> compatible with current WebKit's approach for building HTML pages
What are the WebKit conventions that apply to templates?
The biggest one I can think of is there should be an elegant integration
between the template system and the Page class, because most
applications will be using both together. How will the template
system be integrated with writeHeader, writeBody, writeFooter? Will the
site superclass have one template which the page's class should put the
content into? Or will the writeBody class manage its own template?
Who will do the write()'ing? How can we make this flexible so the
application developer has the most freedom?
> and Zope's idea of acqusition.
It sounds like NameMapper does as much acquisition as we'll need.
One thing is, it may be desirable to limit acqisition. For instance,
I'm not sure that I'll always want the template to go exploring down
through my objects to find plug-in values when I can tell it
specifically which values I want. But I suppose the existing NameMapper
class can handle this if you don't pass it your Page object.
--
-Mike (Iron) Orr, iron@... (if mail problems: mso@...) English * Esperanto * Russkiy * Deutsch * Espan~ol
quaterly.psp
----------------------------------------
<%
import Templates.Report as template
import Reports.Quarterly as report
import Styles.Classic as style
tblWidth = 750
# override the tblWidth in the Classic style
# all style properties can be overriden in this manner
introParagraph = '''
This is our quaterly report. Blah blah blah blah blah
blah blah blah blah blah blah blahblah blah blah
blahblahblah blah blah blahblah blah blah blah blah
blah blahblah blah'''
exec template.write()
%>
-----------------------------------------
template.write() returns a code object, that executes the
following code in
the current local namespace when called with python's exec
statement:
# from TemplateFiller import BoundTemplate
# if not hasattr(locals(),'style'):
# style = {}
# _boundTemplate = BoundTemplate(template.template,
# locals(), style, template.defaults)
# self.write( _boundTemplate.output() )
Variable names embedded in the template are searched for in
locals() first. If they aren't found there it searchs style
and then Templates.Reports.defaults
If you don't like the exec/codeObject approach you could
either type this code in yourself or include it as a psp
include. However, exec template.write() is much
easier for beginners.
Alternately, you can type this
-> exec template.saveOutput('reportHTML')
to assign the output to the variable reportHTML
in this namespace, where you can do whatever you want
with it: caching, filtering, self.write(reportHTML), etc.
Each template would have .write() and .saveOutput methods
that return code objects that look for variables it wants
from the names space the method is called from, like style
in the example.
-----------------------------------------)
- Sasa
Tavis Rudd wrote:
> I just realized that it's very simple to extend the
> template frame I just posted so it can handle something
> like this:
> ----------------------------------------
> quaterlyReport.tmpl
> (accessed as an URL, and processed similar to PSP)
> the var values defined in this file would be fed into a
> template that is stored in another file/package.
> ----------------------------------------
> <@template
> or <@template
>
> <set var="type">Quaterly</set>
>
> <set var="bgColor">white</set>
> <set var="tblWidth">750</set>
>
> <set var="introParagraph">
> This is our quaterly report. Blah blah blah blah blah blah
> blah blah blah blah blah blahblah blah blah blahblahblah
> blah blah blahblah blah blah v blah blah vblah blahblah
> blah
> </set>
>
> -----------------------------------------
> Is this all valid XML?
Except for the @template: use <template package="Report"/> and it is.
> Of course all the xml crap can be intimidating so here's my
> preferred route:
> -----------------------------------------
> @useTemplate: Report
>
> type = Quarterly
> bgColor = white
> tblWidth = {num} 750
> innerTblWidth = {num} %[tblWidth]-20
>
> introParagraph = <<<EOT
> This is our quaterly report. Blah blah blah blah blah blah
> blah blah blah blah blah blahblah blah blah blahblahblah
> blah blah blahblah blah blah v blah blah vblah blahblah
> blah
> EOT
>
> Your thoughts?
>
This looks almost like python (but a little more like perl, and way too much like sh). Why not make it python and skip writing the parser?
----------- foo.instance ----
template = Template("Report")
type = "Quarterly"
bgColor = "white"
tblWidth = 750
innerTblWidth = tblWidth-20
introParagraph = """
This is our quaterly report. Blah blah blah blah blah blah
blah blah blah blah blah blahblah blah blah blahblahblah
blah blah blahblah blah blah v blah blah vblah blahblah
blah
"""
----------
The instantiation code looks something like this:
-----------
from whatever import Template
def applyTemplateInstance( filename, defaults )
ns = {}
ns.update(defaults)
execfile(filename, globals(), ns )
ns['template'].fill( ns )
----------
Who is going to write this file? A programmer or a designer? the XML is going to be easier to build fancy tools for to keep the designers happy.
Tavis Rudd wrote:
> I agree with all of this. It's a perfect compromise.
>
> On Thursday 05 April 2001 06:52, you wrote:
> > About dict-like access for fields, sessions, cookies,
> > etc.
> >
> > I'd propose that it also could be used as:
> >
> > request = self.request()
> > fields = request.fields()
> > foo = fields['foo']
> > cookies = request.cookies()
> > baz = cookies['baz']
> > cookies['abc'] = 'def'
>
You can already do this.
> > AND as:
> >
> > request = self.request()
> > fields = request.fields()
> > foo = fields.foo
> > cookies = request.cookies()
> > baz = cookies.baz
> > cookies.abc = def
> >
Change the _fields object to an instance of MiscUtils.NamedValueAccess.
cookies are slightly more complicated, since each cookie is itself a mapping type. hmm.
Thanks to Tavis and Mike for being interested into Templates subject.
I think that we should somehow join our efforts to make a good
template based solution compatible with Webware's approach.
Of course, first, we need some kind of spec.
What I am going to do in my next postings is to make a small
discussion on next subjects:
- how PHPLib's template system works
- what template system should be and what template system should not be
- make a proposal on how to implement template system that will be
compatible with current WebKit's approach for building HTML pages
This discussion will be based on my experience in builbing template
based solutions in our last 6 web projects combining PHPLib's Template class
and Zope's idea of acqusition.
- Sasa
> -----Original Message-----
> From: Tavis Rudd [mailto:tavis@...]
> Sent: 5. apríl 2001 17:55
> To: Sasa Zivkov; Webware-discuss@...
> Subject: Re: [Webware-discuss] Templates (Again)
>
>
> Sasa,
> I've been working on something very similar to what Mike
> just posted. It's only a few hours off now...
> The two modules it uses are attached.
>
> In the meantime, can you refresh me on how PHPLib does it?
>
> In brief, what I'm working on:
> - uses templates with variable names inserted like this:
> """ a template with a %[varName]"""
> """ a template that calls a %[function] """
> """ a template that calls a %[object.method] """
> """ a template that calls a %[function('with args')"""
> """ a template that calls a method of an obj in a dict
> %[dict.object.method(argA=anotherVarName)] """
> """ a template that is linked to an object and can call
> its methods directly %[methodA(arg=1234)]
> """ a template that is linked to an object and can access
> its attributes directly %[myAttribute.subItem1]
>
>
> - can search for the variable names in a template in a
> cascade of objects, dictionaries, classes, BTrees,
> etc. So if you want to override only a few values and
> use the defaults for everything else, it's very easy
> (see the example below)
>
> - caching, nesting of templates and all conditional logic
> are left to standard python or python/psp. This gives
> the user max. flexibilty to use TemplateFiller how they
> see fit.
>
> It allows you to do something like this:
> ----------------------------------
> from Templates.Report import template, defaults
> from TemplateFiller import BoundTemplate
>
> from Styles import formalStyle
> from Reports.Quarterly import reportData
>
> myValues = {
> 'bgColor': '#FFFFFF',
> 'tableWidth': 750,
> 'reportStyle': formalStyle(),
> 'reportData': reportData()
> }
>
> output = BoundTemplate(template, myValues, defaults).fill()
> response.write(output)
> -----------------------------------
> BoundTemplate fills the template with the values from
> myValues first, and it the variables in the template can't
> be found in myValues it gets them from defaults. It will
> continue searching through however many dictionaries you
> provide it with.
>
> BTW, you can leave the () off formalStyle and any other
> callable objects in myValues (functions, etc.).
> BoundTemplate will recognize them as callable.
>
> Of course all this would be daunting to a non-programming
> so it could all be abstracted into a single function to
> hide all the plumming. They would then type this instead:
>
> writeReport(type='Quaterly', style='formalStyle',
> tableWidth=750)
>
> Tavis
>@...
>
>
>
Chuck Esterbrook wrote:
> >Application could easily become a Manager-- then it would make sense for
> >AppServer to "own"/manage it.
>
> I don't understand what that means besides changing the name of the class...
> Can you expand on how your idea of "Manager" is different from the current
> Application?
"Manager" meaning one of many available services or plugins.
>
> I thought Application was semi-independent already: it doesn't know what
> servlets are going to do to generate their content; only that servlets must
> generate content.
>
See the Admin example below.
>
> >Manager/Service/Plugin seem to be very similar in purpose.
>
> Plug-ins are just Python packages with the added convention that they are
> Webware components (e.g., have a Properties.py) and an InstallInWebKit() hook.
>?
> > > 'ports': {
> > > 8086: 'WKRRProtocol', # WKRR = WebKit Request-Response
> > > 80: 'HTTPProtocol',
> > > },
> > >
> > > WebKit.Protocol would be the base class from which these other classes
> > > would derive.
> >
> >I would like to have something a little more general than this. What you
> >call a Protocol, I call a Connector (the connector (aka Adapter)
> >communicates using the "protocol").
>
>.
Compelling example: I would like to manage the server remotely, but in my paranoia, I want to be able to run the admin context on a nonstandard port that I can lock down with TCPWrappers. I would also like to not have the admin context available from the standard namespace. (This is where Application needs to become separate from Container.)
> > > I did, in fact, intend Application to be a singleton.
> >
> >All the more reason to make Connector not a singleton. 8-)
>
> In the design I'm currently thinking of, there is one AppServer, one or
> more Applications (but typically just one) and the AppServer has multiple
> protocols. Each one digests a request into a Python Request instance which
> then gets rolled into a transaction and sent on to a servlet.
That is what I am thinking too. Just don't call the adapter/connector a protocol.
> That's fine, but I'd like to see a script that can generate these from a
> full fledged component. So you'd have:
>
> PSP-3.01.tgz (everything)
> PSP-bare-3.01.tgz
> ...
Yes. That works too.
> >(In particular, I don't think PSP.InstallInWebKit should add its example
> >context to app. I'm sure this was just an oversite.)
>
> Yeah, basically it was a hack to cover the fact that WebKit will not
> automatically pick up Example contexts from plug-ins.
And SHOULD not. The webmaster should control what gets served. This is a good case for being able to run many appserver processes. The install script can muck all it wants to with the Examples server, and not touch the Production server.
> >Another to add:
> > * have an option to ship the docs already generated, intead of creating
> > them in install.py. This would also allow DocSupport to be factored back
> > out into a separate package.
>
> You mean WebKit/DocSupport or Webware/DocSupport? In any case, yes those
> need more attention.
I never could figure out the difference.
> Shipping generated docs? Seems like a serious waste of bandwidth.
huh?
does anyone have any sample code for working with the DBPool class?
jack.
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Overview
In C++, dynamic memory allocation is done by using the new and delete operators. There is a similar feature in C using malloc(), calloc(), and deallocation using the free() functions. Note that these are functions. This means that they are supported by an external library. C++, however, imbibed the idea of dynamic memory allocation into the core of the language feature by using the new and delete operators. Unlike C's dynamic memory allocation and deallocation functions, new and delete in C++ are operators and are a part of the list of keywords used in C++.
Although, in both C and C++, dynamic memory is allocated in the heap area and gets a pointer returned to the object created, C++ is stricter in the construction norms. C++ never gives the memory of the allocated element direct access to initialize, but a constructor is used instead so as to ensure that:
- Initialization is guaranteed.
- There is no accidental access to an uninitialized object.
- A wrong sized object can't be returned.
Prior to the use of object created, proper initialization is vital. This one thing can help in avoiding many programming problems. Also note that the operators in C++ actually performs twin functions—it dynamically allocates the memory and also invokes the constructor for proper initialization.Prior to the use of object created, proper initialization is vital. This one thing can help in avoiding many programming problems. Also note that the operators in C++ actually performs twin functions—it dynamically allocates the memory and also invokes the constructor for proper initialization.
The cleanup procedure with the delete operator also automatically calls the destructor. Although both C and C++ both have a dynamic memory allocation feature, C++ has made it more elegant.
Dynamic Memory Management
The allocation or deallocation of an object—be it arrays of any built-in type or any user-defined type—can be controlled in memory at runtime by using the new and delete operators.
The new Operator
The new operator allocates the exact amount of memory required by the object during execution. The allocation is performed on the free memory area, called the heap, assigned to each and every program especially for the purpose of dynamic memory allocation. The allocation, if successful by using the new operator, returns a pointer to the object; if it fails, a bad_alloc exception is raised. However, on success we can access the object via pointer returned by the new operator.
For example, when we write,
IntArray *intArray = new IntArray(10); MyClass *obj = MyClass;
What happens here is that the new operator allocates the exact amount of memory required by the object in the free store or heap area, invokes the default constructor to initialize the properties of the object, and returns a pointer to the type-specified object allocated in the memory. However, during the allocation process, if the operator finds that there is not enough space in memory to allocate for the object, it throws an exception to indicate the error. The exception gives an opportunity to handle the error programmatically.
Handling new Failures
The following example illustrates how exceptions from new can be raised and handled efficiently through try..catch clauses. Here, we allocate an array of massive values to simulate the failure of the new operator. As soon as it fails, it raises the bad_alloc exception, handled by the catch handler, and is processed further. Here, we have simply printed what caused the exception in the catch block.
#include <iostream> #include <new> int main() { const int SIZE = 10; double *dArray[SIZE]; try { for(int i=0;i<SIZE;++i){ dArray[i] = new double[999999999]; std::cout<<i<<"th object allocated" <<std::endl; } } catch (std::bad_alloc &ex) { std::cerr<<"Exception: "<<ex.what() <<std::endl; } return 0; }
There is another way to handle new failures, by using a function called set_new_handler, defined in the standard <new> header. This function takes a pointer to a function that returns void as an argument. This function is called as soon as the new fails. The idea is similar to what was shown earlier, but without using try...catch.
Here is a quick example.
#include <iostream> #include <new> void myhandler(){ std::cerr<<"myhandler called."<<std::endl; abort(); } int main() { const int SIZE = 10; double *dArray[SIZE]; std::set_new_handler(myhandler); for(int i=0;i<SIZE;++i){ dArray[i] = new double[999999999]; std::cout<<i<<"th object allocated" <<std::endl; } return 0; }
The delete Operator
As soon as we do not need the allocated space, such as, due to object going out of scope, and so forth, we can ensure that the memory occupied is returned back to the store or freed by using the delete operator. The freed memory then again can be reused by succeeding new operator calls. For example, if we write as follows,
double *dArray = new double[50]{}; MyClass *obj = new MyClass;
The empty braces indicate that each element must be initialized with its default initialization. The default initialization of fundamental types is 0.
Now, to deallocate the memory we use the following statement:
delete [] dArray; delete obj;
Note that dArray is an array object; therefore, the square bracket ([]) ensures freeing all of the memory occupied by the array. If we do not use brackets, the result is undefined because some compilers call for the destructor for the first object only whereas other elements of the array remain allocated in the memory.
Therefore, using delete without brackets should be avoided both for user-defined or for built-in arrays. For built-in arrays, it is a runtime error. To ensuring proper destruction of single element, we must use delete instead of delete []; otherwise, the result is undefined.
The delete expression requires an address of an object and always calls the destructor before releasing the memory. Therefore, all the cleanup operations, such as closing an open file, releasing a database connection, and so on, must be put into the destructor.
Some say that it is a good idea to initialize a pointer with null/zero after deleting it because a zero pointer never calls for deallocation. Because deleting an object twice is a bad idea, initializing a pointer with zero/null after deletion just emphasizes the point that it will not call for destruction again.
Four Key Takeaways
The C++ as a language has implemented four noticeable things with dynamic memory allocation.
- Unlike C, the feature is made part of the language and not merely a support from an external library.
- The procedure altogether is made more elegant and efficient with operators.
- These operators are flexible to be overloaded. This means that we can change their behavior to suit our needs.
- We have an option to deal with when the heap runs out of storage.
These are the four key takeaways from dynamic object creation in C++.
Conclusion
Understand that object created in a stack is much more optimal and efficient that objects created in a heap, because the size and lifetime of the object is built into the generated code and known to the compiler prior to compilation. Heap objects, on the other hand, are dynamic and hence involve both time and space overhead. C++ 11's introduction to unique_ptr made dynamic memory allocation management more efficient. For example, it automatically destroys itself when it goes out of scope and returns the space to the free store. The evolution of dynamic object creation in C++ has many other improvements worthy to be noted.
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gss-server
Naturally, the client needs a server to perform a security handshake. Where the client initiates a security context and sends data, the server must accept the context, verifying the identity of the client. In doing so, it might need to authenticate itself to the client, if requested to do so, and it may have to provide a “signature” for the data to the client. Plus, of course, it has to process the data!
gss-server takes this form on the command line (the line has been broken up to make it fit):
gss-server does the following:
Parses the command line.
Translates the mechanism name given on the command-line, if any, to internal format.
Acquires credentials for the caller.
Checks to see if the user has specified using the
inetd daemon for connecting or not.
Establishes a connection.
Gets the data.
Signs the data and returns it.
Releases namespaces and exits.
Following is a step-by-step description of how gss-server works. Because it is a sample program designed to show off functionality, the parts of the program that do not closely relate to the steps above are skipped here.
gss-client begins with the main() function. main() performs the following tasks:
It parses command-line arguments, assigning them to variables:
port, if specified, is the port number to listen on. If no port is specified, the program uses port 4444 as the default.
If -verbose is specified, the program runs in a quasi-debug mode.
The -inetd option indicates that the program should use the inetd daemon to listen to a port; inetd uses stdin and stdout to hand the connection to the client.
If -once is specified, then the program makes only a single-instance connection.
mechanism is the (optional) name of the security mechanism to use, such as Kerberos v5, to use. If no mechanism is specified, the GSS-API uses a default mechanism.
The name of the network service requested by the client (such as
telnet,
ftp, or login service) is specified by service_name.
An example command line might look like this:
It converts the mechanism, if specified, to a GSS-API object identifier (OID). This is because GSS-API functions handle names in internal format.
It acquires the credentials for the service (such as ftp), for the mechanism being used (for example, Kerberos v5).
It calls the sign_server() function, which does most of the work (establishes the connection, retrieves and signs the message, and so on).
If the user has specified using inetd, then the program closes the standard output and standard error and calls sign_server() on the standard input, which inetd uses to pass connections. Otherwise, it creates a socket, accepts the connection for that socket with the TCP function accept(), and calls sign_server() on the file descriptor returned by accept().
If inetd is not used, the program creates connections and contexts until it's terminated. However, if the user has specified the -once option, the loop terminates after the first connection.
It releases the credentials it has acquired.
It releases the mechanism OID namespace.
It closes the connection, if it's still open...
Having acquired credentials for the service, the server program checks to see if the user has specified using
inetd (see Overview: main() (Server)) and then calls sign_server(), which does the main work of the program. The first thing that sign_server() does is establish the context by calling server_establish_context().
inetd is not covered here. Basically, if
inetd has been specified, the program calls sign_server() on the standard input. If not, it creates a socket, accepts a connection, and then calls sign_server()
on that connection.
sign_server() does the following:
Accepts the context.
Unwraps the data.
Signs the data.
Returns the data.
Because establishing a context can involve a series of token exchanges between the client and the server, both context acceptance and context initialization should be performed in loops, to maintain program portability. Indeed, the loop for accepting a context is very similar to that for establishing one, although rather in reverse. (Compare with Establishing a Context.)
The first thing the server does is look for a token that the client should have sent as part of the context initialization process. Remember, the GSS-API does not send or receive tokens itself, so programs must have their own routines for performing these tasks. The one the server uses for receiving the token is called recv_token() (it can be found at recv_token()):
do { if (recv_token(s, &recv_tok) < 0) return -1;
Next, the program */
where
min_stat is the error status returned by the underlying mechanism.
context is the context being established.
server_creds is the credential for the service being provided (see Acquiring Credentials).
recv_tok is the token received from the client by recv_token().
GSS_C_NO_CHANNEL_BINDINGS is a flag indicating not to use channel bindings (see Channel Bindings).
client is the ASCII name of the client.
oid is the mechanism (in OID format).
send_tok is the token to send to the client.
ret_flags are various flags indicating whether the context supports a given option, such as message-sequence-detection.
NULL and NULL indicate that the program is not interested in the length of time the context will be valid, nor in whether the server can act as a client's proxy.
The acceptance loop continues (barring an error) as long as gss_accept_sec_context() sets maj_stat to GSS_S_CONTINUE_NEEDED. If maj_stat is not equal to either that value nor to GSS_S_COMPLETE, there's a problem and the loop exits.
gss_accept_sec_context() returns a positive value for the length of send_tok if there is a token to send back to the client. The next step is to see if there's a token to send, and, if so, to send it:
if (send_tok.length != 0) { . . . if (send_token(s, &send_tok) < 0) { fprintf(log, "failure sending token\n"); return -1; } (void) gss_release_buffer(&min_stat, &send_tok); }
After accepting the context, the server receives the message sent by the client. Because the GSS-API doesn't provide a function to do this, the program uses its own function, recv_token():
if (recv_token(s, &xmit_buf) < 0) return(-1);
Since the message might be encrypted, the program uses the GSS-API function gss_unwrap() to unwrap it: it, and puts the result in msg_buf. Two arguments to gss_unwrap() are noteworthy: conf_state is a flag to indicate whether confidentiality was applied for this message (that is, if the data is encrypted or not), and the final NULL indicates that the program isn't interested in the QOP used to protect the message.
All that is left, then, is for the server to “sign” the message — that is, to return the message's MIC (Message Integrity Code, a unique tag associated with message) to the client to prove that the message was sent and unwrapped successfully. To do that, the program uses the function gss_get_mic():
maj_stat = gss_get_mic(&min_stat, context, GSS_C_QOP_DEFAULT, &msg_buf, &xmit_buf);
which looks at the message in msg_buf and produces the MIC from it, storing it in xmit_buf. The server then sends the MIC back to the client with send_token(), and the client verifies it with gss_verify_mic(). See Verifying the Message.
Finally, sign_server() performs some cleanup; it releases the GSS-API buffers msg_buf and xmit_buf with gss_release_buffer() and then destroys the context with gss_delete_sec_context().().
Back in the main() function, the application deletes the service credential with gss_delete_cred() and, if an OID for the mechanism has been specified, deletes that with gss_delete_oid() and exits.
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Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptuser1601529 Jun 22, 2015 11:21 AM
Hi Experts,
My system configuration contain
OS: Win 7 – 64-bit
ODI : version 11.1.1.7.0 – 64 bit
Oracle DB: 11G – 64 – bit
When I execute a simple Interface from File --> Oracle DB using "LKM File to Oracle (SQLLDR)" is gives error, same Interface runs successfully when "LKM File to SQL" is used.
I am seeing and error is at 6th Step where SQLLDR is been called. Error is:
"org.apache.bsf.BSFException: exception from Jython:
Traceback (most recent call last):
File "<string>", line 22, in <module>
Load Error: See C:\ODI\RAW/SAMPLE.log for details
at org.apache.bsf.engines.jython.JythonEngine.exec(JythonEngine.java:146)
at com.sunopsis.dwg.codeinterpretor.SnpScriptingInterpretor.execInBSFEngine(SnpScriptingInterpretor.java:322)
at com.sunopsis.dwg.codeinterpretor.SnpScriptingInterpretor.exec(SnpScriptingInterpretor.java:170)
at com.sunopsis.dwg.dbobj.SnpSessTaskSql.scripting(SnpSessTaskSql.java:2472)
at oracle.odi.runtime.agent.execution.cmd.ScriptingExecutor.execute(ScriptingExecutor.java:47)77)
at com.sunopsis.dwg.dbobj.SnpSessStep.treatSessStep(SnpSessStep.java:468)
at com.sunopsis.dwg.dbobj.SnpSession.treatSession(SnpSession.java:2128):745)
Caused by: Traceback (most recent call last):
File "<string>", line 22, in <module>
Load Error: See C:/ODI/PRODUCTSQLLDR.log for details
at org.python.core.PyException.doRaise(PyException.java:219)
at org.python.core.Py.makeException(Py.java:1166)
at org.python.core.Py.makeException(Py.java:1170)
at org.python.pycode._pyx0.f$0(<string>:59)
at org.python.pycode._pyx0.call_function(<string>)
at org.python.core.PyTableCode.call(PyTableCode.java:165)
at org.python.core.PyCode.call(PyCode.java:18)
at org.python.core.Py.runCode(Py.java:1204)
at org.python.core.Py.exec(Py.java:1248)
at org.python.util.PythonInterpreter.exec(PythonInterpreter.java:172)
at org.apache.bsf.engines.jython.JythonEngine.exec(JythonEngine.java:144)
... 19 more"
Below is the command executes at the back in Jython.
"
import java.lang.String
import java.lang.Runtime as Runtime
from jarray import array
import java.io.File
import os
import re
ctlfile = r"""C:\ODI\RAW/SAMPLE.ctl"""
logfile = r"""C:\ODI\RAW/SAMPLE.log"""
outfile = r"""C:\ODI\RAW/SAMPLE.out"""
oracle_sid=''
if len('xe')>0: oracle_sid = '@'+'xe'
loadcmd = r"""sqlldr 'GM_ODI_WORK_1/<@=snpRef.getInfo("DEST_PASS") @>%s' control='%s' log='%s' > "%s" """ % (oracle_sid,ctlfile, logfile, outfile)
rc = os.system(loadcmd)
if rc <> 0 and rc <> 2:
raise "Load Error:", "See %s for details and " % loadcmd
# Init Vars
nbIns = 0
nbRej = 0
nbNull = 0
strprt = ""
maxAllowedError = r"""0"""
c = 0
flag = 0
# Open log file
f = open(logfile, "r")
try:
lines = f.readlines()
for line in lines:
if line.rstrip().upper().endswith(r"""GM_ODI_WORK_1.TC$_0SAMPLEFILE:""".upper()):
flag = 1
c = 0
if flag == 1:
if c > 0 and c <= 4:
if c == 1 :
nbIns = int(re.findall("\d+", line)[0])
elif c == 2:
nbRej = int(re.findall("\d+", line)[0])
elif c == 4:
nbNull = int(re.findall("\d+", line)[0])
break
c+=1
strprt = "\n\tIns:\t%s\n\tReject:\t%s\n\tNullField:\t%s" % (nbIns, nbRej, nbNull)
finally:
f.close()
# if some rows has been rejected due to invalide data, check KM option LOA_ERRORS
if rc == 2:
if nbRej > int(maxAllowedError):
raise strprt
break
"
When I printed the value of "loadcmd" then I found the below command and it executes successfully in the command prompt
sqlldr 'GM_ODI_WORK_1/GM_ODI_WORK_1@xe' control='C:\ODI\RAW/SAMPLE.ctl' log='C:\ODI\RAW/SAMPLE.log' > "C:\ODI\RAW/SAMPLE.out"
Can anyone let me understand the root cause why the above sqlldr command not executes from ODI ?
Thanks,
-Vikram Singh
1. Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptSH_INT Jun 22, 2015 11:33 AM (in response to user1601529)
When you run the command from the command line is it on the same server that the ODI agent running the process is located? If yes, does the user profile you use to manually execute the command have the same security profile as the ODI agent?
2. Re: Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptuser1601529 Jun 22, 2015 2:22 PM (in response to SH_INT)
Hi SH,
Everything is on my local system. I am performing all these steps on my laptop. I never faced this issue on my older 32-bit WIN-7 machine but now I have to do the same on 64 bit WIN7 and its not working.
SH wrote:
When you run the command from the command line is it on the same server that the ODI agent running the process is located? If yes, does the user profile you use to manually execute the command have the same security profile as the ODI agent?
I first tried using without agent "Local (No Agent)", it didn't work. Then I tried using after installing of Agent, that too not worked. It should worked at-least using "Local (No Agent)".
Below is the screen-print where I ran the sqlldr command on command prompt and sample records inserted successfully in the table .
Do we need to have some security settings in ODI for "Local (No Agent)" ? I searched this issue under the Oracle community but didn't found any root cause for this.
Thanks,
-Vikram Singh
3. Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptSH_INT Jun 22, 2015 2:40 PM (in response to user1601529)1 person found this helpful
The local agent will run under the OS user that was used to start ODI Studio, so if it is the same user that used to initiate your command window their should not be a difference in terms of the file access profiles
4. Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptuser1601529 Jun 22, 2015 3:17 PM (in response to SH_INT)
Thanks SH for your quick Reply,
Please let me know if there is something I am missing or any help on "File --> Oracle DB" data transfer using SQLLDR. This is very basic level of data transfer and important too. I am interested to do any kind of troubleshooting to find the root cause.
Experts help is greatly appreciated.
Thanks,
-Vikram Singh
5. Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptemonteci Jun 24, 2015 8:01 PM (in response to user1601529)1 person found this helpful
This is a bug in ODI 11.1.1.7 (or lower) and Windwos 7, solved in 12c.
But there is a workaround, please see at oracle support the Doc ID 1634619.1, where the LKM is modified.
Hope it helps.
Emilio
6. Re: Call sqlldr gives error to see log files but no log file exists, same sqlldr command execute at command promptuser1601529 Jun 25, 2015 5:01 AM (in response to emonteci)
Thanks Emilio for let us know that its a bug. Currently I dont have "Support Identifiers" to see the linked Doc ID 1634619.1, can you please paste the instruction or the code inside the LKM.
Your help is really appreciated.
Thanks,
-Vikram Singh
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https://community.oracle.com/thread/3749337
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Bit.
Basics
Before exploring bitwise and bit shift operator in Java, its prerequisite that you must be familiar with binary format, bits, bytes and bit wise operations like AND, OR, XOR, NOT etc. Knowledge of binary arithmetic is also important to understand code written using bitwise operators in Java programming language.
1) Binary format has just two bit, 0 and 1 and that's why is called binary.
2) In binary arithmetic :
0 + 0 = 0
0 + 1 = 1
1 + 1 = 10
3) Negation bitwise operation will change 0 to 1 and 1 to 0 and it’s denoted by ~.
4) OR bitwise operation will return 1 if any of operand is 1 and zero only if both operands are zeros.
5) AND bitwise operation will return 1 only if both operands are 1, otherwise zero.
6) XOR bitwise operation will return 1 if both operands are different e.g. one of them is 1 and other is zero and returns zero if both operands are same e.g. 1,1 or 0,0
7) Integral types in Java (int, long, short and byte) are signed numbers in Java where most significant bit (MSB) represent sign of number. 1 will denote a negative number and 0 as MSB will denote a positive numbers
8) Negative numbers in Java are represented as 2's complement of number. 2's complement of a number is 1's complement + 1 and 1's complement means all zero will turn to 1 and all 1 turned to zero in a binary number e.g. 1's complement of 10 would be 01. and 2's complement of 10 would be 10+1 = 11 (all in binary).
Bitwise operators in Java
Java provides several bitwise operator e.g. ~ for complement, & for AND bitwise operation, | for OR bitwise operation and ^ for bitwise XOR operation. All of these operator implements there respective operation and operates on bit level. By the way bitwise AND and OP operators are entirely different than logical AND && and logical OR operators ||, which operates on boolean variables and also implements AND and OR operation. Bitwise operator compares each bits of two operands, for example if you apply bitwise AND operator & on two integers ( which is a 32 bit data type in Java), bitwise AND will apply AND operation on each bits of both operands.
Bitwise Operators Examples in Java
In this section we will see example of each of bitwise operator e.g. bitwise negation or complement operator (~), bitwise AND (&), bitwise OR(|) and bitwise XOR(^) operator in Java.
Bitwise unary complement operator (~) Example
Bitwise unary complement operator changes bits from 0 to 1, or vice versa and can only be applied on integral types. It’s not applicable on boolean types.For example int variable contains 32 bits; Applying this operator to a value whose bit pattern is 0000 would change its pattern to 11111. Here is an example of bitwise unary complement operator in Java :
int number = 2; //0010
//example of bitwise unary complement operator (~)
System.out.println(" value of number before: " + number);
System.out.println(" value of number after negation: " + ~number);
Output:
value of number before: 2
value of number after negation: -3
Bitwise AND operator (&) Example
Bitwise AND operator works similar to logical AND operator (&&) and returns 1 if both operands are 1. Difference with bitwise AND and logical AND also known as short-circuit AND operator is that, logical AND operator applies only to boolean type. Also bitwise AND operator is denoted by singe & while short circuit AND operator is denoted by &&. If A represent 0010 and B represent 1010 then result of A&B would be 0010. Here is another example of bitwise AND operator in Java
int a = 2; //0010
int b = 4; //0100
//example of bitwise AND operator &
System.out.println("Result of a&b is " + (a&b)); //should be zero
Output:
Result of a&b is 0
Bitwise OR operator (|) Example
Bitwise OR operator is also similar to bitwise AND operator and applies to individual bits. It’s different than short-circuit OR operator, which is denoted by (||) and operates on boolean variable. Bitwise OR operator produce result of OR operation on two bits as shown in below example. Like other bitwise operator in Java, bitwise OR is only applicable to integral types.
int a = 2; //0010
int b = 4; //0100
System.out.println(" value of A bitwise OR B in Java : " + (a|b) );
Output:
value of A bitwise OR B in Java : 6
Bitwise XOR operator (^) Example
Bitwise XOR operator is denoted by ^ and also work on individual bits. There is no short-circuit XOR operator in Java and result of bitwise XOR operator is XOR operation of individual bits. see the truth table of XOR operation for predicting result. in short bitwise XOR operators will return 1 if both bits are different and return 0 if both bits are same. Bitwise XOR operator also offers a nice trick to swap two numbers without using temp variables. Here is a code example of using bitwise XOR operator in Java:
int a = 2; //0010
int b = 4; //0100
System.out.println(" value of a XOR B in Java : " + (a^b) );
Output:
value of a XOR B in Java : 6
Bit Shift operator in Java- Example
Apart from bitwise operators, Java also provides bit shift operators, which can be used to shift bit from one position to another on both left and right side in a number. Java provides three bit shift operator signed left shift operator "<<", signed right shift operator ">>" and unsigned right shift operator ">>>". Left shift operator with sign, shifts bit into left side and fill the empty place with zero, while right shift operator with sign, shifts the bit on right side and fills the empty place with value of sign bit. For positive number it fills with zero and for negative numbers it fills with 1. On the other hand ">>>" right shift without sign operator will only shift the bit towards right without preserving sign of number. As per syntax of bitshift operator, left hand side of operand is the number whose bit needs to be shift and right hand side of operator is how many bits needs to shift. This will be much clear with following example of signed left shift, signed right shift and right shift without sign operators:
public class BitShiftTest {
public static void main(String args[]) {
int number = 8; //0000 1000
System.out.println("Original number : " + number);
//left shifting bytes with 1 position
number = number<<1; //should be 16 i.e. 0001 0000
//equivalent of multiplication of 2
System.out.println("value of number after left shift: " + number);
number = -8;
//right shifting bytes with sign 1 position
number = number>>1; //should be 16 i.e. 0001 0000
//equivalent of division of 2
System.out.println("value of number after right shift with sign: " + number);
number = -8;
//right shifting bytes without sign 1 position
number = number>>>1; //should be 16 i.e. 0001 0000
//equivalent of division of 2
System.out.println("value of number after right shift with sign: " + number);
}
}
Output:
Original number : 8
value of number after left shift: 16
value of number after right shift with sign: -4
value of number after right shift with sign: 2147483644
From above example of bit shift operators in Java, you can imply that signed left shift operators are equivalent of multiplying by 2 and signed right shift operator with sign are dividing by two. I won’t suggest to do that in production quality code, because it reduces readability.
Important points to remember while using bit shift operators in Java
1. Smaller types like byte, short are promoted to int before applying bit shift operator in Java. This requires explicit casting on lower type of result.
2. If number of shift positions exceeds with number of bits in a variable, then remainder operator is used to calculate effective bit movement. For example int variables contains 32 bit, and if you shift bits to 33 times, then its equivalent of shifting bits 33%32 or just 1 time. e.g. 8 >> 33 is equal to 8 >> 1 and this is true for all bit shift operators.
3. Since bit shift operators can simulate divide by 2 and multiplied by 2 operation they can be used to implement fast multiplication and division but on the cost of readability as its difficult to comprehend code written using bit shift operators in Java.
That's all on bitwise and bit shift operators in Java. We have seen basics and examples of different bitwise e.g. AND, OR and XOR and bitshift operators such as right shift, left shift and right shift without sign. Java is very rich in terms of bit wise operations and not only provides operators to manipulate bits but also bit shift operator which can move bits on both left and right direction. Only caveat of bitwise and bit shift operator is readability but they are the first choice if you intend to do fast operations in Java.
Related Java Programming articles from Javarevisited Blog
13 comments :
>> 1's complement of 10 would be 01. and 2's complement of 10 would be 10+1 = 11 (all in binary).
----------
Hm, two's compliment of 10 will be 01+1, which is 10. Right?
@Sergey Rogov, you are absolutely correct, that a typo. Thanks for pointing that out.
"then its equivalent of shifting bits 33%32 or just 1 time. e.g. 8 >> 33 is equal to 8 >> 33"
Don't you mean 8 >> 33 is equal to 8 >> 1
@Anonymous, good catch, you are correct, I actually meant 8 >> 1. Thanks
For positive number it fills with zero and for negative numbers it fills with 1.
Please check this one? is it true or reverse is true?
I have two different variables defined as byte e.g.
byte a;
byte c;
a = a|c;
I have to do the Or operations between them but unfortunatelly does not give the right one. it responds always different values. I wrote a function but nothing changes. Any idea.
The ~ of int 2 should be more like 1111111111111111111111111111101 not 1101 or -3 as you say since ints are 32 bit.
You should probably update your comments here. You have right shifts (with and without) sign saying that the answer should be 16. Obviously 1000 right shifted with sign is 1100 which is your -4 (in 2's complement form). I think you just copied the comments over and forgot to change them.
The ~ of 2(0010) is 1101 which is -5. Right?
The ~ of 2(0010) is 1101 which is -5. Right? - Wrong it is -3.
I am commenting here since most of you have confusion with the ~2:
Explanation:
int number = 2 will store 2 as a 32 bit integer value: 00000000000000000000000000000010
When you do ~2, the bits will be inverted i.e 1 will become 0 and vice versa. The inverted number will be 11111111111111111111111111111101
This number is in 2's complement form represent -3.
Since int stores all the numbers in their 2's complement form the result is -3.
how to multiply by 3 or divide by 3 using bitwise operators ?
Meherprasad ... these are binary operators .. i.e. powers of 2. If you want to do general math, then don't use these operators. (I.e. just do /= 3 or *= 3 instead.)
Or ... invent a base-3 based computer, where each bit represents 3 numbers, then I guess << 1 would be a *= 3 for you ;)
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http://javarevisited.blogspot.com/2013/03/bitwise-and-bitshift-operators-in-java-and-or-xor-left-right-shift-example-tutorial.html?showComment=1381239892818
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In this blog , we will focus on Image Data Augmentation using keras and how we can implement same.
Problem
When we work with image classification projects, the input which a user will give can vary in many aspects like angles, zoom and stability while clicking the picture. So we should train our model to accept and make sense of almost all types of inputs.
This can be done by training the model for all possibilities. But we can’t go around clicking the same training picture in every possible angles and imagine that when the training set is as big as 10000 pictures!
This can be easily be solved by a technique called Image Data Augmentation, which takes an image, converts it and save it all the possible forms we specify.
Image augmentation Introduction
Image augmentation is a technique that is used to artificially expand the data-set. This is helpful when we are given a data-set with very few data samples. In case of Deep Learning, this situation is bad as the model tends to over-fit when we train it on limited number of data samples.
Image augmentation parameters that are generally used to increase the data sample count are zoom, shear, rotation, preprocessing_function and so on. Usage of these parameters results in generation of images having these attributes during training of Deep Learning model. Image samples generated using image augmentation, in general results in increase of existing data sample set by nearly 3x to 4x times.
Implementation
Let’s start with importing all necessary libraries:
pip install tensorflow pip install scipy pip install numpy pip install h5py pip install pyyaml pip install keras
We have installed
scipy ,
numpy ,
h5py ,
pyyaml because they are dependencies required for
keras and since keras works on a
tensorflow backend, there is a need to install that as well. You can read more about tensorflow installation here. We will be using
keras for performing Image Augmentation.
Let’s import keras image preprocessing.
from keras.preprocessing.image import ImageDataGenerator,img_to_array, load_img
Here,
ImageDataGenerator is used to specify the parameters like rotation, zoom, width we will be using to generate images, more of which will be covered later.
img_to_array is used to convert the given image to a numpy array which will be used by the
ImageDataGenerator,
load_img will be used to load the image to modify into our program.
datagen = ImageDataGenerator( rotation_range=40, width_shift_range=0.2, height_shift_range=0.2, shear_range=0.2, zoom_range=0.2, horizontal_flip=True, fill_mode='nearest')
Arguments:
We have used
ImageDataGenerator() here to specify the parameters for generating our image, which can be explained as follows:
rotation_range : amount of rotation
width_shift_range , height_shift_range : amount of shift in width, height
shear_range : shear angle in counter-clockwise direction as radians
zoom_range : range for random zoom
horizontal_flip : Boolean (True or False). Randomly flip inputs horizontally
fill_mode : One of {“constant”, “nearest”, “reflect” or “wrap”}. Points outside the boundaries of the input are filled according to the given mode
After specifying the parameters and storing them in
datagen variable, we move towards importing our image.
img = load_img('lion.jpg')
Here, I am using lion image , you can simply use your own sample image.
x = img_to_array(img) # creating a Numpy array with shape (3, 150, 150) x = x.reshape((1,) + x.shape) # converting to a Numpy array with shape (1, 3, 150, 150)
load_img
is used to load the required image, you can use any image you like but I
would recommend an image with a face like that of a cat, a dog or a
human!
Next, we use
img_to_array to convert the image to something numerical, in this case a numpy array, which can be easily fed into our
flow() function (don’t worry it is explained later!). We store our converted numpy array to a variable
x.
Then, we have to reshape the numpy array, adding another parameter of size 1. We do so in order to make it a numpy array of order 4 instead of order 3, to accommodate a parameter called channels axis. In case of grayscale data, the channels axis should have value 1, and in case of RGB data, it should have value 3.
This is my input image (a lion):
output:
Now that we have our input in form, let’s start producing some output.
i = 0 for batch in datagen.flow(x,save_to_dir='output', save_prefix='lion', save_format='jpeg'): i += 1 if i > 20: break
we use
datatgen.flow() function in each iteration. We have given
x– the numpy array for the input image,
save_to_dir– the directory to save output,
save_prefix– the prefix for the names of the images and
save_format– the image format as input.
This is how our output images will look like:
Notice that each image is a bit different from the other due to zoom, rotation, width or height shift etc. This will help the model you will be building to recognize a large number of images, thus making it more efficient.
So , this is overview of image augmentation in keras.
Moreover follow Machinex page for more updates for same:
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https://blog.knoldus.com/machinex-image-data-augmentation-using-keras/
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In this section you will learn how to sort ArrayList in java. ArrayList support dynamic array that can grow as needed. Array are of fixed length, after array are created they cannot grow or shrink. In this tutorial we will sort the ArrayList using sort method of collection. ArrayList does not have sort method so using sort method collection which sort the Arraylist. Now here is the code to sort the ArrayList in java.
import java.util.ArrayList; import java.util.Collections; public class Sort { public static void main(String args[]) { System.out.println("Sorting of Arraylist"); ArrayList
al= new ArrayList (); al.add("Rose"); al.add("India"); al.add("Welcomes"); al.add("You"); System.out.println("Before Sort"); System.out.println("*****************"); for(String temp:al){ System.out.println(temp);} System.out.println("*****************"); System.out.println("After Sort"); System.out.println("*****************"); Collections.sort(al); for(String temp1:al){ System.out.println(temp1); } } }
Description : In the above code we have taken a ArrayList that can accept string and then adding the element to list and sorting by sort method of collection, lastly displaying the sorted arraylist to console using for each loop.
Output : When you will compile and execute code the output will be displayed as follows :
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Hello, my name is Mariatta. I work as a Platform Engineer at Zapier. I am a Python Core Developer, and I also help organize the PyCascades conference.
At PyCascades, diversity in our community is a priority, not an afterthought. One of the ways we try to achieve this is by having a strong code of conduct and enforcement. To facilitate the reporting of code of conduct issues, Alan Vezina, one of our organizers, created a code of conduct (CoC) hotline. The hotline has since been adopted by PyCon US 2018 and DjangoCon 2018.
Here's how the first PyCascades CoC hotline works. When someone wishes to report a code of conduct issue, they can call the hotline number. At that time, all of our organizers will be notified, and the caller will then be connected to the first organizer who responds. For accountability, information about the call is also posted to a Slack channel, so we have a record of the call.
Since the hotline launched, I've been thinking of ideas for how the hotline can be enhanced for the coming year.
In this blog post, I'm going to show you how I used Nexmo Voice API and Zapier to enhance the PyCascades Code of Conduct Hotline.
These are the features in the enhanced hotline:
- The caller is greeted, letting them know that they've reached PyCascades Code of Conduct Hotline. It is important that the caller knows they've reached the correct number, the official PyCascades Code of Conduct Hotline.
- All calls are automatically recorded. Code of Conduct reporting is an important and sensitive matter. Having a recording helps us to stay accountable, as well as allowing us to go back and replay the call so we don't miss any details.
Hold music now plays while the caller is waiting to be connected to one of our staff members.
When an organizer answers the call, the caller will hear a message identifying the organizer: "Mariatta is joining this call."
We've added an alert to let the organizer know that this call is regarding PyCascades Code of Conduct. I screen my calls. I often ignore calls from 1-800 numbers or unknown calls whose number I don't recognize. During the conference period, I need to know whether these calls are regarding Code of Conduct issues (which I should take), or if the calls are a telemarketing call offering me a free cruise (which I will ignore).
A ledger of all CoC call activities is now logged in a Google Spreadsheets.
In addition, the following feature still needs to work:
- Info about incoming calls to the CoC hotline posted to Slack. Slack is one of the main ways PyCascades organizers communicate. The Slack message serves as both notification, and a record that a call took place, even if no one answered.
Other technical info:
The hotline is written in Python, and my web framework of choice is aio an async web server and client framework for Python. I've used aiohttp to build GitHub bots like miss-islington and black-out.
The web service is deployed to Heroku. Most of The PSF's web infrastructure is hosted on Heroku, so as a Python core developer, I've been more familiar with Heroku than other types of cloud infrastructure.
One of the main reasons for choosing Nexmo API, for me, is because Nexmo has supported the Python community in many ways including sponsoring PyCon US 2018, DjangoCon 2018 and the first ever PyCascades ? The other reason for choosing Nexmo API is because the nexmo-python library is available open source, and it is compatible with the newer Python versions and tested against Python 3.7.
You can view the source code of the Enhanced CoC Hotline..
Nexmo Voice App Setup
First, let me give you a walkthrough of how my Nexmo Voice application is set up.
When setting up a Voice application in Nexmo, you need to configure two webhook URLs, an Event URL and an Answer URL.
The Event URL is always required; this is where Nexmo will send you information whenever there is a change in the state of the call.
Receiving the Events webhook and logging the activities
The following is an example payload delivered by the Event webhook:
{ "status": "started", "direction": "outbound", "from": "12025550124", "uuid": "80c80c80-80ce-80c8-80c8-80c80c80c80c", "conversation_uuid": "CON-be2be2be-a0dd-a0dd-a0dd-34b34b34b34b", "timestamp": "2018-10-25T17:42:17.552Z", "to": "12025550124" }
It contains information like the caller's number, which number was dialled, the status of the call, the timestamp, and unique call and conversation identifiers. This is all useful information that can be logged so we have records of each activity.
Instead of creating my own web service to receive these webhooks, I've created a Zapier integration. One of the integrations you can use in Zapier is Webhooks by Zapier. With Webhooks by Zapier, you can receive data from any service or send requests to any URL without writing code or running servers. In other words, you can receive and give webhooks.
When I created a new Zap using Webhooks by Zapier as the trigger action, Zapier generated a "hooks.zapier.com" URL that I can use for receiving the webhooks. I supplied the hooks.zapier.com URL as the Events URL in Nexmo Voice Application.
Now that I've set up Zapier to receive the events webhook from Nexmo, I can do many things. First, I added a Slack integration, so a message is automatically posted in our private CoC channel about incoming calls to the hotline. Next, I added a Google Sheets integration, so any activities related to the hotline are automatically added as a new row in Google Sheets.
Answering calls
When a caller dials in the number for the hotline, Nexmo will send the payload of that event to the answer URL. The Answer URL needs to return an NCCO (Nexmo Call Control Object) that governs this call.
The answer URL is set to my webservice's
/webhook/answer/ URL. (source code)
I wanted the caller to be greeted and notified that they've reached the PyCascades Code of Conduct Hotline. Therefore, the first NCCO I returned is a "talk" action:
ncco = [ { "action": "talk", "text": "You've reached the PyCascades Code of Conduct Hotline. This call is recorded." } ]
Next, since I'm now receiving events when a caller has dialled the hotline, I need to call all of our staff members and connect them to the same call. For this, I need to add the caller and the staff into a conference call.
To add callers into a conference call I'll add a "conversation" NCCO action with the same name.
{ "action": "conversation", "name": conversation name, }
So, do I need to make up a "name" for the conversation? Not necessarily. Take a look at the payload delivered the Answer URL
An example GET request to the answer_url is as follows:
Notice that the payload includes a
conversation_uuid. Instead of "making up" new names for the conversation, I decided to use the same
conversation_uuid as the conversation name.
So I retrieved the
conversation_uuid from the request and used it in the NCCO.
conversation_uuid = request.rel_url.query["conversation_uuid"].strip() ... { "action": "conversation", "name": conversation_uuid, ... }
To record the conversation, I can specify
"record": True in the conversation NCCO dictionary. When the recording ends, Nexmo will also send a webhook to the
eventUrl, and the payload to this webhook will include the url where the recording is stored.
The following is an example payload to the recording
eventUrl webhook:
{ " }
Again, instead of configuring my own web service to receive the webhook, I made use of Webhooks by Zapier. I created a different Zap for receiving the recording webhooks.
In this Zap, I added a Google Spreadsheet integration, so that the information from the payload, including the
recording_url, are automatically added as a new row in Google Spreadsheets. In addition, I added a Slack integration so that our staff members are notified of the new recording.
At this point, the conversation NCCO looks like the following:
conversation_uuid = request.rel_url.query["conversation_uuid"].strip() ... { "action": "conversation", "name": conversation_uuid, "record": True, "eventUrl": [os.environ.get("ZAPIER_CATCH_HOOK_RECORDING_FINISHED_URL")], ... }
At this point, there are two things that I need the hotline to do. First, I need it to call each staff member, so I can add them to the conversation. And second, I need it to play some music while the caller is waiting to be connected.
Play music while the caller waits
Playing music into this call is quite straightforward. Add the
"musicOnHoldURL" to the NCCO, and supply a url to the music to be played, for example:
"musicOnHoldUrl": ["
I’m using the music from Wistia’s Music collection, specifically from The Let ‘Em In Sessions. You can view the license for these music here.
import random MUSIC_WHILE_YOU_WAIT = [ " " " " " ] ncco = { ... "musicOnHoldUrl": [random.choice(MUSIC_WHILE_YOU_WAIT)], }
Call the other staff members to the conference call
Now I need to call each of the staff members and add them to this call.
This is not something I can accomplish in the NCCO. So I made use of the Nexmo Python
client library. It can be installed using
pip, so I added
nexmo to my requirements.txt file.
I created a helper function for instantiating the client.
def get_nexmo_client(): app_id = os.environ.get("NEXMO_APP_ID") private_key = os.environ.get("NEXMO_PRIVATE_KEY_VOICE_APP") client = nexmo.Client(application_id=app_id, private_key=private_key) return client
I also created a helper function for retrieving the staff phone numbers. The phone numbers are stored as environment variables in Heroku, in the following format:
[ { "name": "Mariatta", "phone": "12025550124" }, { "name": "Miss Islington", "phone": "12025550123" } ]
The helper function is quite straightforward:
import json def get_phone_numbers(): return json.loads(os.environ.get("PHONE_NUMBERS"))
Now that I have functions to retrieve the nexmo client, as well as the phone numbers to dial, I can dial the numbers.
To call a number using Nexmo Python client library:
response = client.create_call({ 'to': [{'type': 'phone', 'number': 12025550124}], 'from': {'type': 'phone', 'number': 12025550123}, 'answer_url': [' })
In the
create_call call method, I needed to supply the
to phone number, as well as the
from phone number. The
to phone number is the staff's phone number that I'd like to call.
For the
from number, instead of giving the hotline caller's phone number, I used the
hotline number itself; this way, the staff knows by reading the caller ID that this call is from the hotline.
What about the
answer_url? The
answer_url is the webhook for when a staff answers this call. The desired behavior here is that the staff who answered the call gets added to the conversation where the hotline caller is. Therefore, in addition to the Nexmo-provided payload to the webhook, I need to pass in the
conversation_name (which is the
conversation_uuid).
I created a new endpoint in my web service to handle this webhook by including both the
conversation_uuid and the call
uuid to in the URL:
@routes.get( "/webhook/answer_conference_call/{origin_conversation_uuid}/{origin_call_uuid}/" ) async def answer_conference_call(request): origin_conversation_uuid = request.match_info["origin_conversation_uuid"] origin_call_uuid = request.match_info["origin_call_uuid"] ...
With this endpoint created, whenever a staff member answers the call from the hotline, I will have a way to find out which conversation to add them to.
Finally, the answer webhook looks like the following:
@routes.get("/webhook/answer/") async def answer_call(request): conversation_uuid = request.rel_url.query["conversation_uuid"].strip() call_uuid = request.rel_url.query["uuid"].strip() ncco = [ { "action": "talk", "text": "You've reached the PyCascades Code of Conduct Hotline. This call is recorded.", }, { "action": "conversation", "name": conversation_uuid, "record": True, "eventMethod": "POST", "musicOnHoldUrl": [random.choice(MUSIC_WHILE_YOU_WAIT)], "eventUrl": [os.environ.get("ZAPIER_CATCH_HOOK_RECORDING_FINISHED_URL")], "endOnExit": False, "startOnEnter": False, }, ] client = get_nexmo_client() phone_numbers = get_phone_numbers() for phone_number_dict in phone_numbers: client.create_call( { "to": [{"type": "phone", "number": phone_number_dict["phone"]}], "from": { "type": "phone", "number": os.environ.get("NEXMO_HOTLINE_NUMBER"), }, "answer_url": [ f" ], } ) return web.json_response(ncco)
Adding Staff Members to the Conference Call
The
answer_conference_call endpoint was created with the purpose of adding the staff members to the conference call. To accomplish this, I needed to return an NCCO to the webhook that contains a "conversation" action and the name of the conversation. But before they are added, I'd like to greet the staff so they know that they're joining the PyCascades Code of Conduct Hotline.
Recall that the
PHONE_NUMBERS environment variable also includes the names of the phone number owner.
I created the following function to retrieve the name of the phone number owner:
def get_phone_number_owner(phone_number): phone_numbers = get_phone_numbers() for phone_number_info in phone_numbers: if phone_number_info["phone"] == phone_number: return phone_number_info["name"] return None
With that function, I can greet the staff as follows:
@routes.get( "/webhook/answer_conference_call/{origin_conversation_uuid}/{origin_call_uuid}/" ) async def answer_conference_call(request): to_phone_number = request.rel_url.query["to"] origin_conversation_uuid = request.match_info["origin_conversation_uuid"] phone_number_owner = get_phone_number_owner(to_phone_number) ncco = [ { "action": "talk", "text": f"Hello {phone_number_owner}, connecting you to PyCascades hotline.", }, { "action": "conversation", "name": origin_conversation_uuid, "startOnEnter": True, "endOnExit": True, }, ] return web.json_response(ncco)
At this time, you might be wondering, what the
origin_call_uuid is used for. I figured that it could be a nice courtesy to let the hotline caller know that which member of the PyCascades staff is answering their call. Also, remember that this is a conference call, so potentially more than one person may join. Instead of letting someone join silently, I'm giving a heads up to everyone in the call of who just joined.
client = get_nexmo_client() response = client.send_speech( origin_call_uuid, text=f"{phone_number_owner} is joining this call." )
So now the
answer_conference_call endpoint looks like the following:
@routes.get( "/webhook/answer_conference_call/{origin_conversation_uuid}/{origin_call_uuid}/" ) async def answer_conference_call(request): to_phone_number = request.rel_url.query["to"] origin_conversation_uuid = request.match_info["origin_conversation_uuid"] origin_call_uuid = request.match_info["origin_call_uuid"] phone_number_owner = get_phone_number_owner(to_phone_number) client = get_nexmo_client() try: response = client.send_speech( origin_call_uuid, text=f"{phone_number_owner} is joining this call." ) except nexmo.Error as er: print( f"error sending speech to {origin_call_uuid}, owner is {phone_number_owner}" ) print(er) else: print(f"Successfully notified caller. {response}") ncco = [ { "action": "talk", "text": f"Hello {phone_number_owner}, connecting you to PyCascades hotline.", }, { "action": "conversation", "name": origin_conversation_uuid, "startOnEnter": True, "endOnExit": True, }, ] return web.json_response(ncco)
The Completed Call Flow
With that, the enhanced PyCascades Code of Conduct is completed.
The complete call flow is as follows:
- A caller dials the hotline.
- PyCascades staff members receive a Slack notification that there is an incoming call to the hotline.
- Information on the call is added to Google Sheets.
- Caller hears a message: "Welcome to the PyCascades Code of Conduct Hotline. This call is recorded."
- Caller hears music while they wait to be connected.
- Each PyCascades staff receive a call from the hotline.
- A PyCascades staff answers the call, and hears, "Hello {staffname}, connecting you to PyCascades hotline."
- Meanwhile, the caller hears the message "{staffname} is joining this call."
- Staff and caller continue the conversation.
- Staff hangs up, at which point the call recording is completed.
- Staff members receive a Slack notification that there is a new recording.
- Information on the recording is also added in Google Sheets.
Downloading the Recording
The recording can be downloaded by using Nexmo Python client, and the
recording_url is the url received in the recording events webhook.
client = get_nexmo_client() recording = client.get_recording(recording_url)
Call recordings are stored in Nexmo for one month before they get automatically deleted. Since these calls are important and we don't want to lose the recordings, I've created a command line script that can be used to downloading the recordings.
The script can be run as follows:
python3 -m download_recording url1 url2 url3 ...
Once the script is run, the recordings are downloaded and stored locally in the
recording directory.
Conclusions
Thanks to Nexmo and Zapier, I'm able to enhance the PyCascades Code of Conduct hotline. Setting up this hotline does seem to be more complicated than before.
However, I believe the new enhancements like auto-recording, auto-logging in Google Spreadsheets are useful to all of our staff members, so I'm willing to spend the extra time to set this up for PyCascades. In addition, by using Zapier instead of hardcoding it, we can be more flexible in case we want to add additional integrations.
Thanks for reading! If you have further questions, regarding the hotline, PyCascades, or Zapier, please do not hesitate to email me at mariatta.wijaya@zapier.com
Note from Nexmo Developer Relations: We’re super happy Mariatta decided to use Nexmo to help make PyCascades Code of Conduct reporting better. We believe having a CoC is a vital part of creating a welcoming and inclusive space. We’d like to show our support to any conference or meet-up which would like to run a Code of Conduct hotline. If you are an event organiser and you would like to use Mariatta’s Code of Conduct hotline for your event please email devrel@nexmo.com and we’ll happily support you in setting up the application and with some free Nexmo credit.
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https://developer.vonage.com/blog/2018/11/15/pycascades-code-of-conduct-hotline-nexmo-voice-api-dr
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Fighting Condensation in the Smart Home
Monitoring humidity, checking weather forecasts and predicting when condensation might occur. An alerting system for the Smart Home.
Living in Scotland, I’m no stranger to condensation. As a student, I once lived in a tenement flat where even my phone screen would be wet on a morning. Armed with data from my smart heating system, I was finally ready to fight back. I set up an alerting system that texts my phone on evenings where there’s a risk of waking up to wet windows.
Where’s the data?
I previously wrote about hacking my smart heating system and logging its data to Amazon Web Services. I have a setup that pushes temperature, humidity and heating data to S3 — Amazon’s ‘simple storage service’.
Hacking my Smart Heating with AWS
Logging from radiator valves to Amazon Web Services, via NodeMCU, Lambda functions, S3 and Athena.
medium.com
I also needed weather forecast data to work out how cold my windows might get at night. There are plenty of options for free APIs to use, being British I opted for the Met Office’s DataPoint service.
Weather API
The Met Office’s DataPoint API offers free, 3 hourly forecasts for 5,000 sites in the UK. You just need to register a personal account to get an API key. There’s an endpoint to retrieve the list of locations and their corresponding IDs:<key>
I looked up the ID for my nearest forecast site and queried the forecast endpoint with it:<key>
The response is fairly comprehensive, with forecasts for the next week covering weather type, temperature, ‘feels like’ temperature, wind, rain, visibility, UV and humidity.
I wrote some Golang code to parse the JSON response and calculate the coldest temperature forecast over the coming evening. The plan was to create an AWS Lambda function that queries the weather each hour, checks the readings in the house, and alerts if condensation is likely.
The Maths Bit
Calculating the Dew Point
The temperature below which moisture in air starts to condense is called the dew point. It can be approximated using the Magnus formula:
I took the b=17.62 and c=243.12℃ constants from an application note I found, which cites a journal article from the 80s. The note shows that these values give a very good approximation for any temperature we’re likely to see in the home.
I implemented the Magnus formula within my AWS Lambda function:
func dewpoint(T float64, RH float64) float64 {
b := 17.62
c := 243.12
H := math.Log(RH/100) + (b*T)/(c+T)
DP := c * H / (b - H)
return DP
}
How cold are my windows?
One complicating factor in this project is that my windows are going to be much colder than the ambient room temperature. Without a sensor attached to the window, I’d need to approximate the window temperature as a function of ambient and external readings. Fortunately, the University of Liverpool hosts a fantastic video showing how to derive the surface temperature of a window.
Windows are typically marketed with a U value in units of W/m²K, being the heat transfer rate per square metre per degree temperature difference. I was happy enough to use a typical value for that to capture the heat loss through the window. I could also assume that the heat transfer out of the window was equal to the heat transfer to the window from the room via convection. Taking a typical heat transfer coefficient h for air in a room gives a heat transfer of:
I didn’t pay enough attention in first-year thermodynamics lectures but the above seems to work well enough. I implemented the simplified window interior surface temperature calculations as below:
func windowSurfaceTemperature(Texterior float64, Tinterior float64, Uvalue float64, Hinterior float64) float64 {
return (Hinterior*Tinterior + Uvalue*Texterior) / (Hinterior+Uvalue)
}
Codensation Alerts
I could now work out when condensation might occur. I could compare the dew point for the moisture in each room against how cold my windows might get through the night. I set the Lambda function to query the current temperature and humidity via Athena every hour in the evening. If condensation is likely, it sends an alert (via a Simple Notification Service topic) with a warning and the related measurements. All that’s left is to open a window or bump up the heating when an alert arrives!
The code for this has been added to the git repo for my Wiser system hacking. I’m quite pleased with this setup but one thing bugs me. Only the room thermostat measures humidity and the Wiser kit comes with just one of those. They’re also much more expensive than the smart radiator valves I have around the house. For this alerting system to really work, I need to measure humidity in every room. Stay tuned for a future blog post on adding DIY humidistats to the system!
Leader image cropped from a photo by Patrick Hendry, via Unsplash.
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https://medium.com/data-day/fighting-condensation-with-data-fec405b69e23
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, 2007-11-08 at 12:08 +0100, Joel Wilsson wrote:
> Anyway, here is the error message I'm getting:
> C:\Program Files\Gtk2Hs\demos\fastdraw>ghc --make FastDraw.hs
> [1 of 1] Compiling Main ( FastDraw.hs, FastDraw.o )
> Linking FastDraw.exe ...
>
> C:\Program Files\Gtk2Hs\demos\fastdraw>fastdraw.exe
> bytes per row: 768, channels per pixel: 3, bits per sample: 8
> fastdraw.exe: gtk/Graphics/UI/Gtk/Gdk/PixbufData.hs.pp:58:0: No instance nor def
> ault method for class operation Data.Array.Base.getNumElements
>
> C:\Program Files\Gtk2Hs\demos\fastdraw>ghc --version
> The Glorious Glasgow Haskell Compilation System, version 6.8.1
Yes. I get the same.
What has happened is that in GHC 6.8.x the definition of the MArray type
class has changed to add a new method getNumElements which is used to do
an extra bounds check to guard against incorrectly written Ix instances.
So we were missing this class method. I've added it in the darcs version
but that doesn't help you a lot in the short term.
There are a couple workarounds, one is to use ghc-6.6.1 (the installer
supports both 6.6.1 and 6.8.1), the other is to use
unsafeRead/unsafeWrite rather than readArray/writeArray. This bypasses
the bounds check that uses getNumElements.
import Data.Array.Base (readArray, writeArray)
unsafeRead/unsafeWrite always use Int indexes.
Duncan
On Thu, 2007-11-08 at 11:33 +0100, Wolfgang Jeltsch wrote:
> Am Donnerstag, 8. November 2007 03:14 schrieb Duncan Coutts:
> > […]
>
> > * multi-platform support with native look
>
> Really? I thought that GTK+ paints all the widgets by itself and therefore
> doesn’t get the native look completely right. Especially not on Mac OS X.
It uses a combination. On Windows it uses the native theming dll to
follow the theme, though yes it has to paint the classic theme itself.
The native look is not 100% but it's really pretty close these days.
Note that I didn't say native look and feel :-)
You're right on OSX it's not close. We're waiting for the native
(non-X11) GTK+ backend on OSX. That's still in development.
> > * LGPL licence
>
> Oh, I didn’t know this. I think, this could be a serious problem. The LGPL
> doesn’t allow usage of the library in proprietary software, except where the
> library code is only linked with the proprietary code. I suppose that GHC
> doesn’t just link different packages but uses information of used packages
> during compiling. This would mean that it’s not possible to build
> proprietary software with Gtk2Hs which would be bad. Please use BSD3 for
> Haskell libraries!
We've used LGPL because that's the license that GTK+ itself uses. If you
think it's a major problem we could see about adding a linking exception
to allow static linking of the Gtk2Hs library. Obviously the GTK+ C libs
are always dynamically linked to satisfying the LGPL there is easy.
It's not that easy to change however as there have been many
contributers so it's not easy to relicence (or add an exception) as we
need their consent.
Another alternative (as of GHC version 6.8.x) is to build Haskell
libraries as dynamic libs. That would then put us in the same situation
as for the GTK+ C libs.
Duncan
Am Donnerstag, 8. November 2007 03:14 schrieb Duncan Coutts:
> [=E2=80=A6]
> * multi-platform support with native look
Really? I thought that GTK+ paints all the widgets by itself and therefore=
=20
doesn=E2=80=99t get the native look completely right. Especially not on Ma=
c OS X.
> * LGPL licence
Oh, I didn=E2=80=99t know this. I think, this could be a serious problem. =
The LGPL=20
doesn=E2=80=99t allow usage of the library in proprietary software, except =
where the=20
library code is only linked with the proprietary code. I suppose that GHC=
=20
doesn=E2=80=99t just link different packages but uses information of used p=
ackages=20
during compiling. This would mean that it=E2=80=99s not possible to build=
=20
proprietary software with Gtk2Hs which would be bad. Please use BSD3 for=20
Haskell libraries!
> [=E2=80=A6]
Best wishes,
Wolfgang
Gtk@... or in our bug
tracker
Contributions and feedback are also most welcome.
Windows release notes:
The installer expects GHC 6.8.1 or GHC 6.6.1.
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https://sourceforge.net/p/gtk2hs/mailman/gtk2hs-users/?viewmonth=200711&viewday=8
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Hi, Hmm, have the new xlib bindings been tested? For instance, when I run the following program: ---------------------------------------------------------------- module Main where import Graphics.X11.Xlib import Graphics.X11.Xlib.Display main :: IO () main = do display <- openDisplay "" root <- rootWindow display $ defaultScreen display getGeometry display root closeDisplay display return () ---------------------------------------------------------------- It prints out: xtest: user error (Error bad status 1 raised in function getGeometry) >From the code it looks like the haskell getGeometry is calling XGetGeometry - which has type Status XGetGeometry(...) - and interpreting the 1 return value as an error (via the internal wrapper 'throwUnlessSuccess' which takes 0 for success). But the Xlib Programming Manual says "Some errors, such as failure to open a font, are indicated by return values of type Status on the appropriate routine ... The returned values are *zero* on failure and *nonzero* on success." (emphasis added) So unless I'm really misinterpreting things, the binding to each and every one of the 13 functions that uses 'throwUnlessSuccess' is wrong. Well, before I realized this I'd gone ahead and written a reasonably significant program against the binding assuming that at least the basics would work, but it seems there is some distance to go before the library is usable. One would think that with a "Stability: provisional" library every function has been run successfully at least once, but I can't imagine that this is the case here. Is there even a working Haskell equivalent of 'basicwin' from the Xlib Programming Manual to test things out? This would also be a helpful example for users. Regards, Frederik --
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http://www.haskell.org/pipermail/libraries/2005-May/003746.html
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The Code Below Is Made In Python 3.7.0! May Not Work In Older Versions!
Just Copy And Paste This!
from tkinter import * import os creds = 'tempfile.temp' # This just sets the variable creds to 'tempfile.temp' def Signup(): # This is the signup definition, global pwordE # These globals just make the variables global to the entire script, meaning any definition can use them global nameE global roots roots = Tk() # This creates the window, just a blank one. roots.title('Signup') # This renames the title of said window to 'signup' intruction = Label(roots, text='Please Enter new Credidentials\n') # This puts a label, so just a piece of text saying 'please enter blah' intruction.grid(row=0, column=0, sticky=E) # This just puts it in the window, on row 0, col 0. If you want to learn more look up a tkinter tutorial :) nameL = Label(roots, text='New Username: ') # This just does the same as above, instead with the text new username. pwordL = Label(roots, text='New Password: ') # ^^ nameL.grid(row=1, column=0, sticky=W) # Same thing as the instruction var just on different rows. :) Tkinter is like that. pwordL.grid(row=2, column=0, sticky=W) # ^^ nameE = Entry(roots) # This now puts a text box waiting for input. pwordE = Entry(roots, show='*') # Same as above, yet 'show="*"' What this does is replace the text with *, like a password box :D nameE.grid(row=1, column=1) # You know what this does now :D pwordE.grid(row=2, column=1) # ^^ signupButton = Button(roots, text='Signup', command=FSSignup) # This creates the button with the text 'signup', when you click it, the command 'fssignup' will run. which is the def signupButton.grid(columnspan=2, sticky=W) roots.mainloop() # This just makes the window keep open, we will destroy it soon def FSSignup(): with open(creds, 'w') as f: # Creates a document using the variable we made at the top. f.write(nameE.get()) # nameE is the variable we were storing the input to. Tkinter makes us use .get() to get the actual string. f.write('\n') # Splits the line so both variables are on different lines. f.write(pwordE.get()) # Same as nameE just with pword var f.close() # Closes the file roots.destroy() # This will destroy the signup window. :) Login() # This will move us onto the login definition :D def Login(): global nameEL global pwordEL # More globals :D global rootA rootA = Tk() # This now makes a new window. rootA.title('Login') # This makes the window title 'login' intruction = Label(rootA, text='Please Login\n') # More labels to tell us what they do intruction.grid(sticky=E) # Blahdy Blah nameL = Label(rootA, text='Username: ') # More labels pwordL = Label(rootA, text='Password: ') # ^ nameL.grid(row=1, sticky=W) pwordL.grid(row=2, sticky=W) nameEL = Entry(rootA) # The entry input pwordEL = Entry(rootA, show='*') nameEL.grid(row=1, column=1) pwordEL.grid(row=2, column=1) loginB = Button(rootA, text='Login', command=CheckLogin) # This makes the login button, which will go to the CheckLogin def. loginB.grid(columnspan=2, sticky=W) rmuser = Button(rootA, text='Delete User', fg='red', command=DelUser) # This makes the deluser button. blah go to the deluser def. rmuser.grid(columnspan=2, sticky=W) rootA.mainloop() def CheckLogin(): with open(creds) as f: data = f.readlines() # This takes the entire document we put the info into and puts it into the data variable uname = data[0].rstrip() # Data[0], 0 is the first line, 1 is the second and so on. pword = data[1].rstrip() # Using .rstrip() will remove the \n (new line) word from before when we input it if nameEL.get() == uname and pwordEL.get() == pword: # Checks to see if you entered the correct data. r = Tk() # Opens new window r.title(':D') r.geometry('150x50') # Makes the window a certain size rlbl = Label(r, text='\n[+] Logged In') # "logged in" label rlbl.pack() # Pack is like .grid(), just different r.mainloop() else: r = Tk() r.title('D:') r.geometry('150x50') rlbl = Label(r, text='\n[!] Invalid Login') rlbl.pack() r.mainloop() def DelUser(): os.remove(creds) # Removes the file rootA.destroy() # Destroys the login window Signup() # And goes back to the start! if os.path.isfile(creds): Login() else: # This if else statement checks to see if the file exists. If it does it will go to Login, if not it will go to Signup :) Signup()
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This notebook contains a solution to a problem posted on Reddit; here's the original statement of the problem:
So, I have two sets of data where the elements correspond to each other:
A = {122.8, 115.5, 102.5, 84.7, 154.2, 83.7, 122.1, 117.6, 98.1, 111.2, 80.3, 110.0, 117.6, 100.3, 107.8, 60.2} B = {82.6, 99.1, 74.6, 51.9, 62.3, 67.2, 82.4, 97.2, 68.9, 77.9, 81.5, 87.4, 92.4, 80.8, 74.7, 42.1}
I'm trying to find out the probability that (91.9 <= A <= 158.3) and (56.4 <= B <= 100). I know that P(91.9 <= A <= 158.3) = 0.727098 and that P(56.4 <= B <= 100) = 0.840273, given that A is a normal distribution with mean 105.5 and standard deviation 21.7 and that B is a normal distribution with mean 76.4 and standard deviation 15.4. However, since they are dependent events, P(BA)=P(A)P(B|A)=P(B)P(A|B). Is there any way that I can find out P(A|B) and P(B|A) given the data that I have?
The original poster added this clarification:
I'm going to give you some background on what I'm trying to do here first. I'm doing sports analysis trying to find the best quarterback of the 2015 NFL season using passer rating and quarterback rating, two different measures of how the quarterback performs during a game. The numbers in the sets above are the different ratings for each of the 16 games of the season (A being passer rating, B being quarterback rating, the first element being the first game, the second element being the second, etc.) The better game the quarterback has, the higher each of the two measures will be; I'm expecting that they're correlated and dependent on each other to some degree. I'm assuming that they're normally distributed because most things done by humans tend to be normally distributed.
As a first step, let's look at the data. I'll put the two datasets into NumPy arrays.
a = np.array([122.8, 115.5, 102.5, 84.7, 154.2, 83.7, 122.1, 117.6, 98.1, 111.2, 80.3, 110.0, 117.6, 100.3, 107.8, 60.2]) b = np.array([82.6, 99.1, 74.6, 51.9, 62.3, 67.2, 82.4, 97.2, 68.9, 77.9, 81.5, 87.4, 92.4, 80.8, 74.7, 42.1]) n = len(a) n
16
And make a scatter plot:
thinkplot.Scatter(a, b, alpha=0.7)
It looks like modeling this data with a bi-variate normal distribution is a reasonable choice.
Let's make an single array out of it:
X = np.array([a, b])
And compute the sample mean
x̄ = X.mean(axis=1) print(x̄)
[ 105.5375 76.4375]
Sample standard deviation
std = X.std(axis=1) print(std)
[ 21.04040384 14.93640163]
Covariance matrix
S = np.cov(X) print(S)
[[ 472.21183333 161.33583333] [ 161.33583333 237.96916667]]
And correlation coefficient
corrcoef = np.corrcoef(a, b) print(corrcoef)
[[ 1. 0.4812847] [ 0.4812847 1. ]]
Now, let's start thinking about this as a Bayesian estimation problem.
There are 5 parameters we would like to estimate:
The means of the two variables, μ_a, μ_b
The standard deviations, σ_a, σ_b
The coefficient of correlation, ρ.
As a simple starting place, I'll assume that the prior distributions for these variables are uniform over all possible values.
I'm going to use a mesh algorithm to compute the joint posterior distribution, so I'll "cheat" and construct the mesh using conventional estimates for the parameters.
For each parameter, I'll compute a range of possible values where
The center of the range is the value estimated from the data.
The width of the range is 6 standard errors of the estimate.
The likelihood of any point outside this mesh is so low, it's safe to ignore it.
Here's how I construct the ranges:
def make_array(center, stderr, m=11, factor=3): return np.linspace(center-factor*stderr, center+factor*stderr, m) μ_a = x̄[0] μ_b = x̄[1] σ_a = std[0] σ_b = std[1] ρ = corrcoef[0][1] μ_a_array = make_array(μ_a, σ_a / np.sqrt(n)) μ_b_array = make_array(μ_b, σ_b / np.sqrt(n)) σ_a_array = make_array(σ_a, σ_a / np.sqrt(2 * (n-1))) σ_b_array = make_array(σ_b, σ_b / np.sqrt(2 * (n-1))) #ρ_array = make_array(ρ, np.sqrt((1 - ρ**2) / (n-2))) ρ_array = make_array(ρ, 0.15) def min_max(array): return min(array), max(array) print(min_max(μ_a_array)) print(min_max(μ_b_array)) print(min_max(σ_a_array)) print(min_max(σ_b_array)) print(min_max(ρ_array))
(89.757197120005102, 121.31780287999489) (65.235198775056304, 87.639801224943696) (9.5161000378105989, 32.564707642175762) (6.7553975307657055, 23.117405735750815) (0.031284703359568844, 0.93128470335956881)
Although the mesh is constructed in 5 dimensions, for doing the Bayesian update, I want to express the parameters in terms of a vector of means, μ, and a covariance matrix, Σ.
Params is an object that encapsulates these values.
pack is a function that takes 5 parameters and returns a
Param object.
class Params: def __init__(self, μ, Σ): self.μ = μ self.Σ = Σ def __lt__(self, other): return (self.μ, self.Σ) < (self.μ, self.Σ)
def pack(μ_a, μ_b, σ_a, σ_b, ρ): μ = np.array([μ_a, μ_b]) cross = ρ * σ_a * σ_b Σ = np.array([[σ_a**2, cross], [cross, σ_b**2]]) return Params(μ, Σ)
Now we can make a prior distribution. First,
mesh is the Cartesian product of the parameter arrays. Since there are 5 dimensions with 11 points each, the total number of points is
11**5 = 161,051.
mesh = product(μ_a_array, μ_b_array, σ_a_array, σ_b_array, ρ_array)
The result is an iterator. We can use
itertools.starmap to apply
pack to each of the points in the mesh:
mesh = starmap(pack, mesh)
Now we need an object to encapsulate the mesh and perform the Bayesian update.
MultiNorm represents a map from each
Param object to its probability.
It inherits
Update from
thinkbayes2.Suite and provides
Likelihood, which computes the probability of the data given a hypothetical set of parameters.
If we know the mean is
μ and the covariance matrix is
Σ:
The sampling distribution of the mean,
x̄, is multivariable normal with parameters μ and
Σ/n.
The sampling distribution of
(n-1) Sis Wishart with parameters
n-1and
Σ.
So the likelihood of the observed summary statistics,
x̄ and
S, is the product of two probability densities:
The pdf of the multivariate normal distrbution evaluated at
x̄.
The pdf of the Wishart distribution evaluated at
(n-1) S.
class MultiNorm(thinkbayes2.Suite): def Likelihood(self, data, hypo): x̄, S, n = data pdf_x̄ = multivariate_normal(hypo.μ, hypo.Σ/n) pdf_S = wishart(df=n-1, scale=hypo.Σ) like = pdf_x̄.pdf(x̄) * pdf_S.pdf((n-1) * S) return like
Now we can initialize the suite with the mesh.
suite = MultiNorm(mesh)
And update it using the data (the return value is the total probability of the data, aka the normalizing constant). This takes about 30 seconds on my machine.
suite.Update((x̄, S, n))
1.6385250666091713e-15
Now to answer the original question, about the conditional probabilities of A and B, we can either enumerate the parameters in the posterior or draw a sample from the posterior.
Since we don't need a lot of precision, I'll draw a sample.
sample = suite.MakeCdf().Sample(300)
For a given pair of values, μ and Σ, in the sample, we can generate a simulated dataset.
The size of the simulated dataset is arbitrary, but should be large enough to generate a smooth distribution of P(A|B) and P(B|A).
def generate(μ, Σ, sample_size): return np.random.multivariate_normal(μ, Σ, sample_size) # run an example using sample stats fake_X = generate(x̄, S, 300)
The following function takes a sample of $a$ and $b$ and computes the conditional probabilites P(A|B) and P(B|A)
def conditional_probs(sample): df = pd.DataFrame(sample, columns=['a', 'b']) pA = df[(91.9 <= df.a) & (df.a <= 158.3)] pB = df[(56.4 <= df.b) & (df.b <= 100)] pBoth = pA.index.intersection(pB.index) pAgivenB = len(pBoth) / len(pB) pBgivenA = len(pBoth) / len(pA) return pAgivenB, pBgivenA conditional_probs(fake_X)
(0.8174603174603174, 0.865546218487395)
Now we can loop through the sample of parameters, generate simulated data for each, and compute the conditional probabilities:
def make_predictive_distributions(sample): pmf = thinkbayes2.Joint() for params in sample: fake_X = generate(params.μ, params.Σ, 300) probs = conditional_probs(fake_X) pmf[probs] += 1 pmf.Normalize() return pmf predictive = make_predictive_distributions(sample)
Then pull out the posterior predictive marginal distribution of P(A|B), and print the posterior predictive mean:
thinkplot.Cdf(predictive.Marginal(0).MakeCdf()) predictive.Marginal(0).Mean()
0.7246540147158328
And then pull out the posterior predictive marginal distribution of P(B|A), with the posterior predictive mean
thinkplot.Cdf(predictive.Marginal(1).MakeCdf()) predictive.Marginal(1).Mean()
0.8221366197059744
We don't really care about the posterior distributions of the parameters, but it's good to take a look and make sure they are not crazy.
The following function takes μ and Σ and unpacks them into a tuple of 5 parameters:
def unpack(μ, Σ): μ_a = μ[0] μ_b = μ[1] σ_a = np.sqrt(Σ[0][0]) σ_b = np.sqrt(Σ[1][1]) ρ = Σ[0][1] / σ_a / σ_b return μ_a, μ_b, σ_a, σ_b, ρ
So we can iterate through the posterior distribution and make a joint posterior distribution of the parameters:
def make_marginals(suite): joint = thinkbayes2.Joint() for params, prob in suite.Items(): t = unpack(params.μ, params.Σ) joint[t] = prob return joint marginals = make_marginals(suite)
And here are the posterior marginal distributions for
μ_a and
μ_b
thinkplot.Cdf(marginals.Marginal(0).MakeCdf()) thinkplot.Cdf(marginals.Marginal(1).MakeCdf());
And here are the posterior marginal distributions for
σ_a and
σ_b
thinkplot.Cdf(marginals.Marginal(2).MakeCdf()) thinkplot.Cdf(marginals.Marginal(3).MakeCdf());
Finally, the posterior marginal distribution for the correlation coefficient,
ρ
thinkplot.Cdf(marginals.Marginal(4).MakeCdf());
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https://allendowney.blogspot.com/2016/04/bayesian-update-with-multivariate.html
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I was writing up a little game kit, when i ran into a little problem. When you enter a command, it skips past all the if/else statements, and defaults to the final else statement.
import java.util.*; //used to make imput work class Text_Game_Kit { //main method, where the game takes place public static void main(String args[]) { //Declaring everything //position as a Y cordinate int POSY = 0; //position as an X cordinate int POSX = 0; //Placeholder for input String input = ""; //The First Chest is not open boolean Chest1 = false; String Chest1OPCL = " closed"; // the first chest is closed. This is to enhance the text. //Is there an enemy? boolean enemy = false; String enemyname = ""; //Type of enemy. i.e. Skeleton, Zombie, etc. // boolean to see if the game is done boolean done = false; //if the game is not done, keep running while (!done) { //quickly check if the game is done. if it is, break everything if (done) { break; } //these are commands. try to see how they work. all commands must be lowercase. //Movement Outputs: tells the user what the character sees if (POSX==0&&POSY==0) //If you are at the starting position: 0,0. You see a chest from here. Reach it by saying "move up" 3 times. { System.out.println("You wake up in a poorly lit room. You see a" + Chest1OPCL + " chest 3 steps to the north"); } else if (POSX==0&&POSY==3) //You have just moved up 3 times. you can open the chest by saing "open" { System.out.println("There is a" + Chest1OPCL + " chest in front of you."); } //Danger Commands: tells the user other information besides the Movement Outputs if (enemy) { System.out.println("You are being attacked by a" + enemyname + "."); } //Get the input input=in(); //handle the input. This includs all do able commands. typing help will list them. typing help and then a command will describe it. The only changing here should be to add commands //Moving Commands if (input==("up")) { POSY++; //move up } else if (input==("down")) { POSY--; //go down } else if (input==("left")) { POSX--; //move left } else if (input==("right")) { POSX++; //move right } //opening commands: deals with: is there a chest, is it open, and what happens else if (input==("open")) { if (POSX==0&&POSY==3&&!Chest1) //if the chest isnt open and you are at 0,3: the place where chest1 is. { System.out.println("You open the chest and find a sword. You hear the rattling of bones behind you."); enemy=true; enemyname=" Skeleton"; Chest1=true; Chest1OPCL="n open"; //now text thinks its open // you open the chest and are now being attacked by a skeleton. use "attack" to kill it. } // you can insert more chests here, you must use else if //if there is no chest else { System.out.println("You see nothing to open!"); } } //Attacking Command else if (input=="attack") { if (enemy) { System.out.println("You attack a" + enemyname + ". It falls rather easily."); //Staging. this is rather difficult because the attack command dosent know what you just attacked. if (enemyname == " Skeleton") { done=true; //in this short kit, killing the skeleton is the end. however, you can use anything here. if you want, you can make this progress, or have another enemy pop up, a door open, etc. if you need help here, just ask. I understand its a bit vague. } } else { System.out.println("You find nothing to attack, so you swing at the air for good measure"); } } //help, and any variants. Add more if you make new commands else if (input=="help") { System.out.println("Commands are: up, down, left, right, open, help, and attack. Say help with a command after it to see more information"); //make sure to put any added here. } //indepth command help else if (input=="help up") { System.out.println("This makes you move fowdard"); } else if (input=="help down") { System.out.println("This makes you move backwards"); } else if (input=="help left") { System.out.println("This makes you move left"); } else if (input=="help right") { System.out.println("This makes you move right."); } else if (input=="help open") { System.out.println("This opens a chest, if there is one."); } else if (input=="help attack") { System.out.println("This attacks an enemy, if there is one."); } else if (input=="help help") { System.out.println("You IQ must me in the double digits"); } //The end of the command cycle. all other commands must be above this else { System.out.println("That is not a command. Try using help to find more commands."); } } //end of the loop. only goes here when the game is done System.out.println("Congradulations! You've won!"); } //This method gets input public static String in() { Scanner scan=new Scanner(System.in); String word = "Temp"; word=scan.next(); return word; } }
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Recently the CES 2020 concluded in Vegas and for those who aren’t aware, CES is the annual trade show for consumer electronics around the world. As such, it an excellent indicator of the direction consumer technology is heading towards in the coming years.
For exampple, the cover image presents to you Neon developed by Samsung’s STAR Labs which are Artificial Intelligence-powered virtual beings that look and behave like real humans. Unlike AI assistants like Siri or Alexa though, Neon isn’t programmed to be “know-it-all bots” or an interface to answer users’ questions and demands. Instead, the avatars are designed to converse and sympathize “like real people” in order to act as hyper lifelike companions. This includes being able to move, express themselves, and speak. They can also remember and learn things about their user, and speak in any language. CEO Pranav Mistry further explains the vision he has for his Neon.
“Neon is like a new kind of life. Neons will be our friends, collaborators, and companions, continually learning, evolving, and forming memories from their interactions.” – Pranav Mistry, Neon’s CEO.
Apart from Neon, there were various innovative products revolving around AI and specifically, Deep Learning.
So that’s wonderful but how is this relevant to the topic at hand you might ask.
Well, CES is often quoted to be the window to the future and that window has shown us that going into this new decade, it’s not going to be possible to talk about technology without in some part involving Artificial Intelligence or Machine Learning & Deep Learning (to be precise).
At Eduonix, we’ve thoroughly covered the officially supported Deep Learning API of Keras. If you’ve missed out, be sure to check the Keras series.
Articles from Kerass Series!
- Deep Neural Networks with Keras
- Functional API of Keras
- Convolutional Neural Networks with Keras
- Recurrent Neural Networks and LSTMs with Keras
Now because Deep Learning is such an active field, every once in a while something comes along that has the potential of changing the landscape in the field of Deep Learning. Facebook’s PyTorch is one such library. Since its stable release in early October 2018, many researchers have adopted it as a go-to library because of its ease of building a novel and even extremely complex graphs. So in the next few blogs, we’ll scuba dive into PyTorch starting with the one today!
Before we start with today’s agenda, however, it would be unfair for us to proceed before making a proper case for the readers of why this blog is worth any of their time. So here’s a little graph showing the unique mentions of PyTorch (solid lines) vs TensorFlow (dotted lines) in various global conferences (marked out with different colors).
To put this into perspective, consider the tabulation below:
But hey! We get it. You’re not into research really rather just an Artificial Intelligence practitioner! Well, here’s another bit of data to put things into even better perspective for the practitioners:
By the end of 2019, TensorFlow had 1541 new job listings vs. 1437 job listings for PyTorch on public job boards. Considering TensorFlow came out several years earlier than a stable release of PyTorch did and the research community, as well as the industry, had adopted TensorFlow as the de facto standard already by then, it’s now come pretty neck to neck between the two.
Read More: A Beginners Guide To Tensorflow – What Is The Big Deal?
A quick note to the readers: although it may seem like Keras is far out in the race, Keras is now officially bundled with every release of TensorFlow which means TensorFlow and Keras is very closely linked to each other. So your Keras expertise is not in vain but quite the opposite in fact!
We’d like to think we’ve made a pretty convincing case for the people working in the industry and also for the practitioners. But if you’re an enthusiast or a hobbyist, just here for the fun, we reckon you’d be just fine ignoring PyTorch since most of the research papers still do have TensorFlow versions of their code released along with the PyTorch versions for you to look at. But we implore you to make this investment today because we don’t know how long it is until TensorFlow versions of the code stop being released altogether by researchers and everything is just PyTorch within the research community. Maybe this year, or the next, who knows? But the dark horse is taking the lead that’s for sure!
Hold up! But what exactly is this PyTorch thing?
Finally! We’re glad you asked. So surprise surprise but PyTorch is not just a Deep Learning framework. The creators had two goals with PyTorch:
- A replacement for NumPy.
- A deep learning platform that provides maximum flexibility and speed.
Let’s start with the first one.
NumPy and PyTorch
We’re all familiar with NumPy and take it for granted because it’s one of the things that just happen to be there somehow in every Machine Learning program???
Well, the reason is that in Machine Learning or Deep Learning, we work with multidimensional arrays. For example, an image is often represented as an array of (height, width, number of color channels). So, for a grayscale (no color) image, we’d represent it as an array of shape (height, width, 1). Similarly, for a color image that would change to (height, width, 3). This is all very standard. It’s also standard to use NumPy to initialize these arrays. In scientific computing, these multidimensional arrays are called ‘Tensors’. I mean, it’s just neat because now instead of calling an image a multidimensional array, I can just call it a tensor.
It goes something like this, a scalar (a single number) has zero dimensions, a vector has one dimension, a matrix has two dimensions and a tensor has three or more dimensions. That’s it!
However, there’s a catch when you use NumPy arrays for computations. You cannot directly leverage the power of GPUs. PyTorch on the other end provides a framework to define tensors with direct GPU compatibility. So basically, PyTorch tensors are similar to NumPy’s arrays, with the addition being that PyTorch tensors can also be used on a GPU to accelerate computing. This is clearly an advantage over NumPy since Deep Learning heavily relies on GPU based model training.
Okay okay, that’s great. But how do I define a PyTorch tensor?
Right. Syntactically, defining a tensor in PyTorch is a breeze. But first, let us install the PyTorch library.
# Python 3.x pip3 install torch torchvision # Python 2.x` pip install torch torchvision # Anaconda conda install pytorch torchvision -c pytorch
Now, let us construct a randomly initialized tensor:
import torch x = torch.rand(5, 3) print(x)
Out:
tensor([[0.7799, 0.1989, 0.5753], [0.4624, 0.5366, 0.7436], [0.8719, 0.9631, 0.3204], [0.8461, 0.0422, 0.3457], [0.9910, 0.8967, 0.5962]])
Now, to construct a tensor filled zeros and of dtype long:
x = torch.zeros(5, 3, dtype=torch.long) print(x)
Out:
tensor([[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]])
That’s how simple it is! Just like NumPy! In fact, you can use standard NumPy-like indexing on these tensors too!
print(x[:, 1])
Out:
tensor([0.1989, 0.5366, 0.9631, 0.0422, 0.8967])
The syntax for addition remains exactly the same as for NumPy. For multiplication, we can use the torch.matmul(x, y) and for division, torch.div(x, y) where x and y are PyTorch tensors.
Hey! You know what? That’s cool. But why should I adopt PyTorch when I’m already so comfortable with NumPy?
Ah! See that’s the thing. PyTorch is not expecting that you migrate over to PyTorch leaving NumPy. In fact, NumPy arrays and PyTorch tensors are interconvertible!
We use the from_numpy() method!
import numpy as np # define a NumPy array a = np.ones(5) # convert into pyTorch tensor b = torch.from_numpy(a) # change the NumPy array np.add(a, 1, out=a) print(a) print(b)
Out:
[2. 2. 2. 2. 2.] tensor([2., 2., 2., 2., 2.], dtype=torch.float64)
Notice how changing the NumPy array changed the PyTorch Tensor automatically!
We’ve mentioned earlier that the entire power of PyTorch over NumPy lies in able to leverage GPU acceleration. But what is the syntax for it?
So let’s say we’ve got NumPy arrays and access to a GPU and would like to speed up our computations using PyTorch,
Here’s how we go about it:
import torch # check if a GPU device is available. If not, use the CPU device = 'cuda' if torch.cuda.is_available() else 'cpu' # The data is in NumPy arrays x and y, but we need to transform them into PyTorch's Tensors to leverage GPU speed. # So we convert them using earlier syntax and then we send them to the chosen device x_tensor = torch.from_numpy(x).to(device) y_tensor = torch.from_numpy(y).to(device)
Simple as that!
PyTorch seems a good choice for a GPU. But what if I don’t have one? Why should I use PyTorch then?
That’s a very valid question. So let us throw some speed tests your way.
Clearly, PyTorch is faster than NumPy in basic mathematical operations. This is because of the faster array element access that PyTorch provides.
Let’s go for one more speed test. We’ll take a one-dimensional vector having size 10 billion random elements. And, try to access the middle element from both NumPy, as well as PyTorch.
The result is decisive, PyTorch is clearly a winner in array traversing. It took about 0.00009843 seconds in PyTorch, while over 0.01 seconds for NumPy!
So should you completely ditch NumPy and use PyTorch everywhere? Not just yet. If you’re using TensorFlow, you’re probably better off using NumPy to avoid compatibility issues but if you’re using PyTorch to build your models, we highly recommend using PyTorch instead of NumPy.
Ha! Maybe I’ll just use both and convert them into each other as and when required!
While that’s a very possible thing to do, we recommend against such a practice because interconversion between these two data types is both computationally heavy, and complex. And it is best to avoid doing so.
So we talked about NumPy vs PyTorch with its basic syntax and compared the two on a variety of factors before coming to a conclusion. Now let’s move on and talk about why PyTorch has so rapidly gained popularity among the research community!
PyTorch as a Deep Learning Framework
PyTorch differentiates itself from other machine learning frameworks in that it does not use static computational graphs – defined once, ahead of time – like TensorFlow, Caffe2, or MXNet. Instead, PyTorch computation graphs are dynamic and defined by a run.
Woah Woah Woah! There’s too much happening! What does any of this even mean???
Alright. Let’s go over it nice and slow.
Dynamic vs Static Graphs
Generally, in the majority of programming environments, adding two variables x and y representing numbers produces a value containing the result of that addition.
For example, in standard Python:
x = 4 y = 2 x + y
Out:
6
However, this is not the case in a static graph environment like TensorFlow. In TensorFlow, x and y would not be numbers directly, but would instead be handles to graph nodes representing those values, rather than explicitly containing them. Furthermore, and more importantly, adding x and y would not produce the value of the sum of these numbers, but would instead be a handle to a computation graph, which, only when executed, produces that value:
import tensorflow as tf x = tf.constant(4) y = tf.constant(2) x + y
Out:
<tf.Tensor 'add:0' shape=() dtype=int32>
As such, when we write TensorFlow code, we are in fact not programming, but metaprogramming – we write a program (our code) that creates a program (the TensorFlow computation graph). Naturally, the first programming model is much simpler than the second. It is much simpler to speak and think in terms of things that are than speak and think in terms of things that represent things that are.
PyTorch’s major advantage is that its execution model is much closer to the former than the latter. At its core, PyTorch is simply regular Python, with support for Tensor computation like NumPy, but with added GPU acceleration of Tensor operations as we’ve seen above.
One of the many reasons for PyTorch gaining popularity is because, going back to the simple showcase above, we can see that programming in PyTorch resembles the natural “feeling” of Python:
import torch x = torch.ones(1) * 4 y = torch.ones(1) * 2 x + y
Out:
6 [torch.FloatTensor of size 1]
The choice of using static or dynamic computation graphs severely impacts the ease of programming. The aspect it influences most severely is the control flow.
In a static graph environment, control flow must be represented as specialized nodes in the graph. For example, to enable branching, TensorFlow has a tf.cond() operation, which takes three subgraphs as input: a condition subgraph and two subgraphs for the if and else branches of the conditional. Similarly, loops must be represented in TensorFlow graphs as tf.while() operations, taking a condition and body subgraph as input. In a dynamic graph setting, all this is simplified. Since graphs are traced from Python code as it appears during each evaluation, control flow can be implemented natively in the language, using if clauses and while loops as you would for any other program.
This turns awkward and unintuitive TensorFlow code:
import tensorflow as tf x = tf.constant(2) y = tf.constant(3) w = tf.while_loop( lambda x: tf.matmul(x, y) < 10, lambda x: tf.square(x), [x]) into natural and intuitive PyTorch code: import torch.nn x = torch.tensor([2]) y = torch.tensor([3]) while x.sum() < 100: x = torch.square(x)
The benefits of dynamic graphs from an ease-of-programming perspective reach far beyond this, of course. Simply being able to inspect intermediate values (like values being passed in and out of complex architecture model layers) with simple Python print statements (as opposed to tf.Print() nodes for TensorFlow) or a debugger is a big plus because computation graph in PyTorch is defined at runtime you can use our favorite Python debugging tools such as pdb, ipdb, PyCharm debugger. This is not the case with TensorFlow. At this stage, it is quite clear why a researcher would be inclined towards using PyTorch rather than TensorFlow!
Okay, I have begun to understand why PyTorch is gaining popularity with the research community but is that all the ways in which PyTorch is different from TensorFlow?
As a matter of fact, the answer is no. Apart from this, there are several other major differences when it comes to PyTorch than a framework like TensorFlow like in visualization support, pipelining support, deployment support, etc! But that’s nothing to worry about because we’ll go all of it in detail in the forthcoming blogs with the next blog being on how to define and train a Deep Neural Network with PyTorch!
We hope this has served as a basic introduction to PyTorch with the emphasis being on why the readers should invest time in PyTorch and the reason why it is gaining popularity with researchers around the world!
I hope that you liked it and we’ll see ya in the next blog!
More From The Series:
#1. PyTorch: The Dark Horse of Deep Learning Frameworks (Part 1)
#2. The Next Step: Building Neural Networks with PyTorch (Part 2)
#3. Marching On: Building Convolutional Neural Networks with PyTorch (Part 3)
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Hey guys I have to create a program that computes the mean, standard deviation, and finds the max and min of a group of numbers read in from a file. I'm having trouble storing the objects from the file in an array and then reading it to compute the mean. Here's what I have so far:
Code :
import java.io.*; import java.util.*; public class Assignment5 { public static void main(String[] args) throws FileNotFoundException { Scanner input = new Scanner(new File("nerd.txt")); double[] data = new double[1000]; double mean = 0; double sum = 0; double n = 0; while (input.hasNextDouble()){ double element = input.nextDouble(); data[element]++; n++; } for(int x = 0; x < data.length; x++){ sum = sum + data[x] * x; } mean = (double)sum / n; System.out.println("The mean is " + mean); } }
I don't really understand arrays. But basically I have to: Use an array to store the numbers being read. Keep a count each time a number is read (this will be N).
I just really don't know how to store the numbers from the file :/. Any help will be greatly appreciated :D
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http://www.javaprogrammingforums.com/%20collections-generics/1589-need-help-making-program-printingthethread.html
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BBC micro:bit
More Buttons
Introduction
This page describes a method for connecting multiple buttons to a single analogue pin using a resistor ladder.
Making The Circuit
The circuit consists of 5 pushbuttons and 6 resistors. The schematic will give you a clearer idea of what is happening.
There is a different value resistor connected from the 3V supply to each switch. The other ends of the switches are connected together through a resistor to the GND pin on the micro:bit. The 1K resistor that connects the buttons to GND will drag our reading close to 0V when no buttons are pressed. When a button is pressed, it brings one of the other resistors into the circuit. These are connected to the power supply and are pulling the reading high, towards 1023 when a button is pressed. The different values of resistor ensure a different reading for each button.
Here is the circuit on a breadboard.
In order to work out how to use the buttons, we need to find the analogue reading that we get for each button. We can do that with a simple program and by printing the readings. Open the REPL window before you flash the program. There will be numbers scrolling down the screen.
from microbit import * while True: reading = pin0.read_analog() print(reading) sleep(20)
Press each button in turn and write down the readings that you get. The readings I got were as follows,
This is pretty good news. There's a lot of room between the readings for each button press. Now to make use of them in a program. The following program uses the LED matrix to display the number of the button being pressed. A little bit of slack is allowed for small variations in the readings we get from things like temperature changes.
from microbit import * while True: reading = pin0.read_analog() if reading>838: display.show("1") elif reading>700: display.show("2") elif reading>513: display.show("3") elif reading>325: display.show("4") elif reading>180: display.show("5") else: display.clear() sleep(10)
Challenges
- Once you have this working, you need to experiment a little. The way that the last program was written changes the behaviour of the buttons when more than one of them is pressed. If you go back to the test program and write down the reading you get for every different combination of buttons, you can see if any of them come out the same. You can then adapt the program to allow at least some combinations of button press.
- 4 buttons on one pin means you could get a Simon Says game going with some lovely buzzing. Shift the input pin along to pin 1 and use pin 0 for a buzzer or some headphones you've hacked. Use the matrix to give instructions and feedback for the game.
- Rearrange the buttons to make a D pad configuration. Write a matrix based program and move a sprite around in 4 directions.
- If you have a wide variety of resistors, you can add some more buttons. You can either experiment with them or look up the reasoning behind the staggered values.
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http://multiwingspan.co.uk/micro.php?page=pybutt
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c# bitarray to int
How can I convert BitArray to single int? - private int getIntFromBitArray(BitArray bitArray) { if (bitArray.Length > 32) throw new ArgumentException("Argument length shall be at most 32
Convert a BitArray to Int in C# - Just copy the bit array to an int array and take the first element. BitArray bitArray = new BitArray(new int[] { 5 }); int[] array = new int[1]; bitArray.
.net - 1 Answer. You've made it much more complicated than necessary. The conversion to a BitArray needlessly copies the values to the bool array bits . You could instead use that on the conversion back to int .
.net - You've made it much more complicated than necessary. The conversion to a BitArray needlessly copies the values to the bool array bits .
BitArray.CopyTo(Array, Int32) Method (System.Collections - array is multidimensional. -or-. The number of elements in the source BitArray is greater than the available space from index to the end of the destination array .
BitConverter.ToInt32 Method (System) - Returns a 32-bit signed integer converted from four bytes at a specified position in a C# Copy. using System; public class Example { public static void Main()
BitArrays Are Cool, C# - BitArrays Are Cool in C#. Next(256); BitArray t = new BitArray(new byte[]{val}); Console. //printing out the bit array as a binary number Console.Write("Binary:
Converting BitArray to short, int, long - I need to read 16, 32, or 64 bits from a BitArray, and get a short, int, long respectively. Does anyone have, or know of a efficient, compact algorithm for doing this.
Convert int to BitArray - C# / C Sharp - I want to convert an int to binary and put the binary number's bits into a BitArray. Anyone know how to do this? -- Message posted via
C# BitArray Class - C# BitArray Class - Learn C# in simple and easy steps starting from basic to You can access items from the BitArray collection by using an integer index, which
bit array
Bit array -.
BitArray Class (System.Collections) - Manages a compact array of bit values, which are represented as Booleans, where true indicates that the bit is on (1) and false indicates the bit is off (0).
Find Duplicates of array using bit array - You have an array of N numbers, where N is at most 32,000. The array may have duplicates entries and you do not know what N is. With only 4 Kilobytes of
bitarray · PyPI - This module provides an object type which efficiently represents an array of booleans. Bitarrays are sequence types and behave very much like usual lists.
Array of bits - The C programming language provides all the necessary operations to allow the programmer (= you) to implement an "array of bits" data structure.
Save space with bit arrays - A colleague of mine had the bright idea to use a bit array, and it worked very well - we were able to compress the data by a factor of 18 or more.
Bit Array Discussions | C++ - Can you by any chance explain to me why some bit array solutions (like the one provided by mohammed_anees:) take much longer
Bit Arrays (Episode 1) - The Bits class is the base class for BitArray and so (with the exception of __hash __ ) all of its methods are also available for BitArray objects. The initialiser is
The BitArray class - C# BitArray Class - Learn C# in simple and easy steps starting from basic to advanced concepts with examples including Overview, Environment setup, Program
C# BitArray Class - Let's start at the very beginning! HTMs rely heavily on bit arrays, so here are the basics. Intro
string to bitarray c#
.NET C# String to Bit Array - MSDN - Answers. First use an encoding to convert the string to an array of bytes. Then use Convert.ToString( n, 2 ) to convert each byte to a string in base 2. You can use .PadLeft( 8, '0' ) to ensure that there are leading zeroes and that it has exactly 8 binary digit characters per byte.
Load a (0/1) string into a bit array - You can do it with LINQ: var res = new BitArray(str.Select(c => c == '1').ToArray()); .
Text to Binary in C# - How would I convert text to binary using c#. Reverse(btText); BitArray bit = new BitArray(btText); StringBuilder sb = new StringBuilder(); for (int
BitArrays Are Cool, C# - BitArrays Are Cool in C#. public class Program { static Random Rand = new Random(); public static void Main(string[] args) { //converting byte --> bool[] as bits
Convert string to binary and binary to string in C# - The following two snippets allow you to convert a string to binary text and also to convert binary back to string. String to binary method: public
Converting BitArray to string - C# Discussion Boards - Dear Friends, i have small problem can U please tell where do i make mistake? i am converting string value "0000000000000001" to byte array then again i am
Convert Byte Array To String In C# - This code snippet is example of how to convert a C# byte array to a string in .NET Core.
C# BitArray Class - C# BitArray Class - Learn C# in simple and easy steps starting from basic to Decision Making, Loops, Methods, Nullables, Arrays, Strings, Struct, Enums, File
C# Convert String to Byte Array - This C# article converts a string to a byte array. It then converts a byte array to a string.
Use the BitArray class in C# - The BitArray class stores an array of Boolean values packed into a bit class. private void Form1_Load(object sender, EventArgs e) { string txt
convert byte array to bit array c#
Convert Byte Array to Bit Array? - The obvious way; using the constructor that takes a byte array: BitArray bits = new BitArray(arrayOfBytes);.
Converting C# byte to BitArray - Yes, using the appropriate BitArray() constructor as described here: var bits = new BitArray(arrayOfBytes); You can call it with new BitArray(new byte[] { yourBite }) to create an array of one byte. if you have a byte number or even an integer, etc.
BitArray Constructor (System.Collections) - Remarks. The first byte in the array represents bits 0 through 7, the second byte represents bits 8 through 15, and so on. The Least Significant Bit of each byte
BitArray.CopyTo(Array, Int32) Method (System.Collections - Copies the entire BitArray to a compatible one-dimensional Array, starting at . array types for CopyTo on BitArrays are Boolean[], Int32[] and Byte[]. at System.
Bit Array To Byte Array (2) : Byte Array « File Stream « C# / C Sharp - Bit Array To Byte Array (2) : Byte Array « File Stream « C# / C Sharp. ArgumentException("must have at least length 1", "bitarray"); } int num_bytes = bitarray.Length / 8; if (bitarray. 1. Convert a byte array to string using default encoding. 2.
Bit Array To Byte Array : Byte Array « File Stream « C# / C - Length - 1; i >= 0; i--) { bool bit = bits[i]; sb.Append(Convert.ToInt32(bit)); } return sb.ToString(); } public static byte[] BitArrayToByteArray(this BitArray bits) { return
BitArrays Are Cool, C# - BitArrays Are Cool in C#. static void Main(string[] args) { //converting byte --> bool[] as bits of a byte byte val = (byte)Rand.Next(256); BitArray t = new BitArray( new byte[]{val}); Console. //printing out the bit array as a binary number Console.
Convert a BitArray to byte[] in C# - Here's an extension method that packs a C# BitArray to a byte array: public static byte[] ToByteArray(this BitArray bits) { int numBytes = bits.
C# BitArray Class - C# BitArray Class - Learn C# in simple and easy steps starting from basic to Type Conversion, Variables, Constants, Operators, Decision Making, Loops, of size 8 BitArray ba1 = new BitArray(8); BitArray ba2 = new BitArray(8); byte[] a
Convert Byte Array to Int in C# - The code snippet in this article converts different integer values to a byte array and vice-versa using BitConverter class.
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Author: Iqbal M. Khan.
In this article, I will discuss how NCache object querying works.
NCache provides an Object Query Language (OQL) to let you search the cache. You have to make API calls and specify a search based on this OQL in order to fetch a collection of objects from the cache. Here is what you need to use in your .NET application in order to query the cache.
public class Program { public static void Main(string[] args) { NCache.InitializeCache("myReplicatedCache"); String query = "SELECT NCacheQuerySample.Business.Product WHERE this.ProductID > 100"; // Fetch the keys matching this search criteria ICollection keys = NCache.Cache.Search(query); if (keys.Count > 0) { IEnumerator ie = keys.GetEnumerator(); while (ie.MoveNext()) { String key = (String)ie.Current; Product prod = (Product)NCache.Cache.Get(key); HandleProduct(prod); Console.WriteLine("ProductID: {0}", prod.ProductID); } } NCache.Cache.Dispose(); } }
The above code searches the cache and returns a collection of keys. Then, it iterates over all the returned keys and individually fetches the corresponding cached items from the cache. The benefit of this approach is that the query does not automatically return a lot of data and instead only returns keys. Then, the client application can determine which keys it wants to fetch. The drawback of this approach is that if you're going to fetch most of the items from the cache anyway, then you'll end up making a lot of trips to the cache. And, if the cache is distributed, this may eventually become costly. If that becomes the case, then you can conduct a search that returns the keys and the items together.
As you have seen already, a simple Cache.Search(...) returns a collection of keys. However, if you intend to fetch all or most of the cached items associated with these keys, then Cache.Search(...) is not a very efficient way to search the cache. The reason is that you'll first make a call to do the search. Then, you'll make a number of calls to fetch the items associated with each key. This can become a very costly operation. In these situations, it is better to fetch all the keys and items in one call. Below is the example doing just that.
public class Program { public static void Main(string[] args) { NCache.InitializeCache("myReplicatedCache"); String query = "SELECT NCacheQuerySample.Business.Product WHERE this.ProductID > 100"; // Fetch the keys matching this search criteria IDictionary dict = NCache.Cache.SearchEntries(query); if (dict.Count > 0) { IDictionaryEnumerator ide = dict.GetEnumerator(); while (ide.MoveNext()) { String key = (String)ide.Key; Product prod = (Product)ide.Value; HandleProduct(prod); Console.WriteLine("Key = {0}, ProductID: {1}", key, prod.ProductID); } } NCache.Cache.Dispose(); } }
The above code searches the cache and returns a dictionary containing both keys and values. This way, all the data based on the search criteria is fetched in one call to NCache. This is much more efficient way of fetching all the data from the cache than doing
Cache.Search().
Please note that NCache requires all searchable attributes to be indexed. This is because without indexing, NCache would have to traverse the entire cache in order to find the items the user is looking for. And, that is a very costly operation with potential of slowing down the entire cache and undo the major reason why people would NCache, namely to boost their application performance and scalability.
NCache provides its own indexing mechanism. You can identify the objects in your .NET assemblies that you want to index. Then, when you add data to NCache, it checks to see whether you're adding these objects. And, if you are, then it uses .NET Reflection to extract data from the indexed attributes and builds its internal index. Then, when you query the cache with Cache.Search() or Cache.SearchEntries(), NCache uses these indexes to quickly find the desired objects and returns them to you.
Figure 1: NCache Manager lets you index object attributes before starting your cache
Please note that any time you specify indexes on object attributes, it adds a little bit to the processing time for Add, Insert, and Remove operations. However, Get operation is unaffected.
Although, the search behavior from the client application's perspective is the same regardless of what caching topologies you're using, the internals of search vary from topology to topology. For example, if you're doing a search on a replicated cache, your search is conducted entirely on the cache server you initiated this search from. This is because the entire cache is available there. Here is how a query is run in a replicated cache.
Figure 2: Query runs locally on one server
However, if you have partitioned or partitioned-replica caching topology, then not all the data resides on a single cache node in the cluster. In this situation, the cache server where the query is initiated sends the query to all other servers in the cluster and also runs it locally. The query then runs in all servers in a parallel and its results are returned from all the nodes to this originating server node. This server node then combines all the results (does a "union") and returns them to the client. Below is a diagram showing all of this.
Figure 3: Query runs in parallel on all server nodes
In NCache, indexing is done on the server nodes. However, NCache uses .NET Reflection on the client-end to extract the values of object attributes and sends them to the server. Therefore, your .NET assemblies that contain the object definition are only required on the client-end where your application resides. Whether you're running in InProc or OutProc mode, your assemblies need to be in a directory where your client application can access them.
Additionally, NCache also supports object query language for Java clients.
NCache supports SQL-like language called Object Query Language (OQL). This language has the following syntax in NCache.
SELECT NCacheQuerySample.Business.Product WHERE this.ProductID > 100"; SELECT NCacheQuerySample.Business.Product WHERE (this.ProductID != 100 AND this.ProductID <= 200); SELECT NCacheQuerySample.Business.Product WHERE (this.ProductID == 150 OR this.ProductID == 160); SELECT NCacheQuerySample.Business.Product WHERE this.ProductID IN (1, 4, 7, 10); SELECT NCacheQuerySample.Business.Product WHERE this.ProductID NOT IN (1, 4, 7, 10); SELECT NCacheQuerySample.Business.Employee WHERE this.HiringDate > DateTime.now; SELECT NCacheQuerySample.Business.Employee WHERE this.HiringDate > DateTime ('01/01/2007'); SELECT NCacheQuerySample.Business.Employee WHERE this.Hired = true;
You can combine multiple expressions together with AND and OR and by using nested parenthesis. The full query language syntax grammar is specified below.
<Query> ::= SELECT <ObjectType> | SELECT <ObjectType> WHERE <Expression> <Expression> ::= <OrExpr> <OrExpr> ::= <OrExpr> 'OR' <AndExpr> | <AndExpr> <AndExpr> ::= <AndExpr> 'AND' <UnaryExpr> | <UnaryExpr> <UnaryExpr> ::= 'NOT' <CompareExpr> | <CompareExpr> <CompareExpr> ::= <Atrrib> '=' <Value> | <Atrrib> '!=' <Value> | <Atrrib> '==' <Value> | <Atrrib> '<>' <Value> | <Atrrib> '<' <Value> | <Atrrib> '>' <Value> | <Atrrib> '<=' <Value> | <Atrrib> '>=' <Value> | <Atrrib> 'IN' <InList> | <Atrrib> 'NOT' 'IN' <InList> | '(' <Expression> ')' <Atrrib> ::= <ObjectValue> <Value> ::= '-' <NumLiteral> | <NumLiteral> | <StrLiteral> | 'true' | 'false' | <Date> <Date> ::= 'DateTime' '.' 'now' | 'DateTime' '(' StringLiteral ')' <StrLiteral> ::= StringLiteral | 'null' <NumLiteral> ::= IntegerLiteral | RealLiteral <ObjectType> ::= '*' | <Property> <Property> ::= <Property> '.' Identifier | Identifier <ObjectValue> ::= Keyword '.' Identifier <InList> ::= '(' <ListType> ')' <ListType> ::= <NumLiteralList> | <StrLiteralList> | <DateList> <NumLiteralList> ::= <NumLiteral> ',' <NumLiteralList> | <NumLiteral> <StrLiteralList> ::= <StrLiteral> ',' <StrLiteralList> | <StrLiteral> <DateList> ::= <Date> ',' <DateList> | <Date>
As you have seen, NCache makes it very simple to query the distributed cache. This is a powerful feature that allows you to use your cache in a more meaningful way and find things in it more easily. Check it out.
Author: Iqbal M. Khan works for Alachisoft, a leading software company providing .NET and Java distributed caching, O/R Mapping and SharePoint Storage Optimization solutions. You can reach him at iqbal@alachisoft.com.
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void Telegraph::send_message(const char* message) {
//Telegraph/examples/HelloWorld/HelloWorld.pde#include "telegraph.h"const unsigned int OUTPUT_PIN = 13;const unsigned int DIT_LENGTH = 100;Telegraph telegraph(OUTPUT_PIN, DIT_LENGTH);void setup() {}void loop() { telegraph.send_message("SM"); //note that there were no entries for punctuation marks in the Morse Code character array delay(5000);}
//Telegraph/Telegraph.pdevoid setup() ()void loop() {}
//Telegraph/telegraph.cpp#include <ctype.h>#include <WProgram.h>#include "telegraph.h"char* LETTERS[] = { ".-", "-...", "-.-.", "-..", ".", // A-E "..-.", "--.", "....", "..", ".---", // F-J "-.-", ".-..", "--", "-.", "---", // K-O ".--.", "--.-", ".-.", "...", "-.--", // P-T "..-", "...-", ".--", "-..-", "-.--", // U-Y "--.."};char* DIGITS[] = { "-----", ".----", "..---", "...--", // 0-3 "....-", ".....", "-....", "--...", // 4-7 "---..", "----."}(); }}void Telegraph::dit() { Serial.print("."); output_symbol(_dit_length);}void Telegraph::dah() { Serial.print("-"); output_symbol(_dah_length);}void Telegraph::output_symbol(const int length) { digitalWrite(_output_pin, HIGH); delay(length); digitalWrite(_output_pin, LOW);}void Telegraph::send_message(const char* message) { for (int i = 0; i < strlen(message); i++) { const char current_char = toupper(message[i]); if (isalpha(current_char)) { output_code(LETTERS[current_char - 'A']); delay(_dah_length); } else if (isdigit(current_char)) { output_code(DIGITS[current_char - '0']); delay(_dah_length); } else if (current_char == ' ') { Serial.print(" "); delay(_dit_length * 7); } } Serial.println();}
//telegraph/telegraph.h#ifndef __TELEGRAPH_H__ // this line is part of the "double-include" prevention mechanism - allowing TELEGRAPH_H to only be compiled ONCE. #define __TELEGRAPH_H__ // this line defines the "body" of the header file as a preprocessor macro __TELEGRAPH_H__ ONLY if it has not been previously defined. class Telegraph { //create class Telegraph public: // This is the PUBLIC part of the class that users of the class have access to Telegraph(const int output_pin, const int dit_length); void send_message(const char* message); private: //This is the PRIVATE part of the class only members of the class can use void dit(); //declare function dit() void dah(); //declare function dah() void output_code(const char* code); //declare function "output_code" with parameter void output_symbol(const int length); //declare function "output_symbol" with parameter int _output_pin; int _dit_length; int _dah_length; };#endif
I.
But when I tried removing "strlen(message)" and replacing it with the number 4 (to get it to loop 4 times) the result was still the same as above.
Telegraph::Telegraph(const int output_pin, const int dit_length) { _output_pin = output_pin; _dit_length = dit_length; _dah_length = dit_length * 3;}void Telegraph::begin(){ pinMode(_output_pin, OUTPUT);}
Serial.print("Pattern to output: ");Serial.println(code);
I have a project built from a book called Arduino: A Quick-Start Guide, which is a Morse Code generator...what I am getting is simply one "." followed by one "-", repeating every 5 seconds. It seems to be a problem with a loop of some sort.
void Telegraph::output_symbol(const int length) { digitalWrite(_output_pin, HIGH); delay(length); digitalWrite(_output_pin, LOW); delay(_dit_length); // davekw7x: This separates the dits and dahs within a character}
telegraph.send_message("CQ CQ CQ de W1AW");
QuoteI.Which version of the IDE are you using?
... the LED will see between 0.25 to 0.1 milliAmps of current. With Arduino Pin 13 set as an input...Enough to light-up a small LED...quite dim
//// From davekw7x: A way to query the mode of an Arduino I/O pin//// This is a simplified function to get mode of I/O pin.//// For a somewhat more robust one, see replies #5 and #8 at// #include <pins_arduino.h>int getPinMode(unsigned int p){ // Convert designated Arduino pin to ATMega port and pin uint8_t pbit = digitalPinToBitMask(p); uint8_t pport = digitalPinToPort(p); if (pport == NOT_A_PIN) { return -1; } // Read the ATmega DDR for this port volatile uint8_t *pmodereg = portModeRegister(pport); // Test the value of the bit for this pin and return // 0 if it is reset and 1 if it is set return ((*pmodereg & pbit) != 0);}
#include "telegraph.h"const unsigned int OUTPUT_PIN = 13;const unsigned int DIT_LENGTH = 100;Telegraph telegraph(OUTPUT_PIN, DIT_LENGTH);void setup(){ Serial.begin(9600); // // davekw7x: Find out whether the LED pin is an Input or an Output // int mode = getPinMode(OUTPUT_PIN); Serial.print("Pin "); Serial.print(OUTPUT_PIN); Serial.print(" is operating in "); if (mode == INPUT) { Serial.print(" IN"); } else { Serial.print("OUT"); } Serial.println("PUT mode."); }
It is version 0022
QuoteIt is version 0022Then you do not need to go through all those steps. Modify the library. Save it. Verify or Upload. That's it. No need to restart or any of the other stuff.
No. It's a problem with your dit and dah functionality.I don't have that particular book, so I can't say whether it is correct, but here's the deal for Morse: dits and dahs in a character are separated by delays of dit duration.So:For a "dit" The LED should go high for _dit_length, and low for _dit_length.For a "dah" the LED should go high for _dah_length and low for _dit_length.To implement this you can make a simple change in your class code:
If the class that you posted is directly and correctly copied from the book, then it is obvious that the code wasn't tested. That's not a Good Thing. (See Footnote.)Regards,Dave
...That fixed it!!
...when you print a book, and the information in it is wrong, it stays wrong forever.
Which steps, exactly, are you referring to that I don't need?
But I like the IDE's assistance in showing colors, following braces, and allowing me to verify the code.
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Tree Traversals. The diagram below shows a limited version of a book with only two chapters. Note that the traversal algorithm works for trees with any number of children, but we will stick with binary trees for now.
.
The code below is a simple Python implementation of a preorder
traversal of a binary tree. This approach is particularly elegant because our
base case is simply to check if the tree exists. If the tree parameter
is
None, then the function returns without taking any action.
def preorder(node): if node: print(node['val']) preorder(node.get('left')) preorder(node.get('right'))
The algorithm for the
postorder traversal, shown below, is nearly identical to
preorder
except that we move the call to print to the end of the function.
def postorder(node): if node: postorder(node.get('left')) postorder(node.get('right')) print(node['val'])
We have already seen a common use for the postorder traversal, namely evaluating a parse tree. What we did in the previous chapter to evaluate the parse tree was to evaluate the left subtree, evaluate the right subtree, then combine them in the root through the function call to an operator.
The final traversal we will look at in this section is the inorder
traversal. In the inorder traversal we visit the left subtree, followed
by the root, and finally the right subtree.
Notice that in all three of the traversal functions we are
simply changing the position of the
def inorder(node): if node: inorder(node.get('left')) print(node['val']) inorder(node.get('right')) below.
def construct_expression(parse_tree): if parse_tree is None: return '' left = construct_expression(parse_tree.get('left')) right = construct_expression(parse_tree.get('right')) val = parse_tree['val'] if left and right: return '({}{}{})'.format(left, val, right) return val
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Camera Usage and Features, from iOS* to Windows* 8 Store App
Publicado el 17 de abril de 2013
Download Article
Download Camera Usage and Features, from iOS* to Windows* 8 Store App [PDF 1.26MB]
Abstract
Modern applications take advantage of camera features to enable new types of usage models and enhanced user experiences. In this article we will cover how to use the camera feature in a Windows* 8 Store app to take pictures and how to convert the picture into base64 encoding, which can then be transmitted as JSON data over the network to a backend server or persisted into a local database. We will also discuss how iOS* camera usage compares to Windows 8 and some tips on migrating your code.
Contents
- Overview
- Camera Controls and UI
- A Healthcare Line of Business Windows Store App
- Migrating Camera related code from iOS to Windows 8
- Summary
Overview
The camera is one of the most used features in mobile device applications. Users can capture photos or record videos with different configuration settings. All of the modern OS platforms like iOS and Windows 8, provide APIs and platform services to make camera usage seamless for the end user and easy to use for the programmer. This gives users a well-known user interface to interact with the camera, common across all apps. Some apps may create a fully customized camera usage depending on their requirements, but for most applications the default usage is recommended.
In this article we will cover how iOS developers can port their camera-related code to a Windows 8 Store app. We will discuss how to invoke the default camera UI control, process the result using async programming patterns, and use the Image control to display the picture in a Windows Store app UI.
We will also cover how to encode and decode the picture to/from base64 format, which can be very useful in line of business apps that may require transmitting the image over the network as JSON data for RESTful backend services.
Camera Controls and UI
The default camera UI controls come with some standard options that users can tweak. They usually handle all user interactions with the camera UI, including the touch gestures, finally returning the result (captured picture or video) to the code invoking it (via delegates or asynchronous callbacks).
Depending on the API settings, the camera controls let users edit the picture (e.g., crop) and customize as needed. For advanced editing and customization, we may have to develop our own camera UI control as the default control capabilities are limited.
These controls also provide a way for users to play with different device camera capabilities like flash, brightness, and other standard features depending on the platform.
The code required to use these controls is usually simple and easy to integrate as long as you stick to the platform recommended API usage patterns.
A Healthcare Windows Store App
Like we did in several other articles in this forum, we will build the case study around a healthcare Windows Store application. We will extend it with the capability to take a picture and update the patient’s profile., such as the profiles, doctor’s notes, lab test results, vital graphs, etc.
Figure 1: The “Patients” page of the Healthcare Line of Business app provides a list of all patients. Selecting an individual patient provides access to the patient’s medical records.
In Figure 1 all the profile pictures are shown as generic avatars. With the camera feature enabled, we will be able to update those images to the most recent profile picture of each patient as needed.
Migrating Camera related code from iOS to Windows 8
The iOS platform provides you with both a default camera UI control option and a more advanced custom solution that has greater flexibility. UIImagePickerController API gives us the simple, default, common camera usage for taking pictures and the AV foundation framework has the fully customizable solution. This document has more details:
iOS developers looking to port camera-related features in their apps to Windows 8 Store apps can use the default camera UI and control, CameraCaptureUI, which is part of Windows.Media.Capture namespace.
Using the Windows 8 camera UI and some tips on delegating the code
In this article we assume basic familiarity with Windows Store app development. Similar to other modern OSs (e.g., iOS), Windows 8 Store apps must declare camera capability in the app manifest. Double clicking on the Package.appxmanifest in your Visual Studio* 2012 project should bring up a manifest UI that you can use to tweak the settings. Figure 2 shows the webcam capability enabled in the manifest, which lets us use the camera feature.
Figure 2: App manifest showing the webcam package capability (captured from Visual Studio* 2012)
Our project should now be ready to access the camera feature.
When the app accesses the camera for the first time, Windows 8 brings up a user permission dialog allowing the user to either block or enable camera access. Figure 3 shows an example.
Figure 3: Camera permission dialog (capture from Windows* 8)
As discussed previously, Windows Store apps can use the system-provided default camera UI control (CameraCaptureUI class under Windows.Media.Capture namespace) for most of the use cases. This has an additional advantage in that users will already be familiar with the UI controls, gestures, and usage.
The app usually invokes the camera control in response to some kind of user action—a button click or a touch gesture.
Figure 4 shows the app bar with a camera button labeled “Photo.”
Figure 4: Camera button and icon (captured from Windows* 8)
We can use the Windows standard icon (
PhotoAppBarButtonStyle) for styling our camera button. Figure 5 shows the sample XAML code for a camera button as part of the app bar.
<Button x:
Figure 5: XAML code for camera button and default icon as part of app bar ++
In Windows 8 the button click input events from all sources (touch, mouse, etc.) are automatically routed to the same input handler, in this case the Command property (PatientPicCmd binding). The PatientPicCmd command is covered later in this article.
It is usually recommended to design your code in an MVVM pattern for XAML-based apps. Please refer to the article below for more details on MVVM:
This allows us to implement our button event handler logic inside the patient view model and use the same view model and logic in any UI page of the app by simply binding to properties. Figure 6 shows another UI page where we have another camera button. No need for re-implementing the button click handler in XAML code behind, as we simply bind to the same patient view model class (which has our camera button click handler logic).
Figure 6: Another UI page with camera button (captured from Windows* 8)
Invoking the camera dialog is straightforward in Windows 8. We just have to create an instance of CameraCaptureUI class, configure the instance with any custom settings, and then show the camera UI dialog with CaptureFileAsync method of the instance. Since this method is implemented as an async pattern, we will need to use the await keyword to invoke it.
For more details on asynchronous programming in Windows 8 Store apps, please refer to the following article.
Figure 7 shows sample code for invoking the default camera UI in Windows 8.
private async void DoPatientPicCmd(object sender) { try { CameraCaptureUI dialog = new CameraCaptureUI(); dialog.PhotoSettings.CroppedAspectRatio = new Size(4, 3); // fix the photo size to 300x300 //dialog.PhotoSettings.CroppedSizeInPixels = new Size(300, 300); StorageFile photo = await dialog.CaptureFileAsync(CameraCaptureUIMode.Photo); if (photo == null) return; // custom process the photo } catch (Exception ex) { // custom exception handling code } }
Figure 7: Sample code for invoking camera UI dialog ++
The CameraCaptureUI class has two main properties: PhotoSettings and VideoSettings. We can invoke the Camera Dialog in Photo mode only by specifying “CameraCaptureUIMode.Photo” when invoking the dialog.
PhotoSettings is an instance of the CameraCaptureUIPhotoCaptureSettings class and can be used to specify options such as cropping, aspect ratio, max resolution, and format. Please refer to the following article for more details:
In our sample code we enabled cropping with an aspect ratio 4:3. Figure 8 shows the default Camera UI dialog. It has the video option disabled since we invoked the control with photo mode. Other options are change camera (to switch to back, front, or other cameras), camera options (e.g., resolution), and timer functionality.
Figure 8: Default camera UI dialog (captured from Windows* 8)
Users can either single tap or click anywhere on the screen to take a photo. Depending on the configuration, the app brings up another dialog allowing users to crop or edit the picture. The edit options are basic and limited. For advanced editing, a custom camera UI control is recommended (or you can add a process for editing later).
Figure 9: Camera UI control allows basic editing (captured from Windows* 8)
After users are satisfied with their photos, they can click ok to accept, or retake as needed. After a successful action (photo is captured and OK is selected), the camera UI dialog returns the photo captured as an image file (instance of “StorageFile” class in Windows.Storage namespace), which can then be processed further or persisted to data model.
Converting the photo image file into an image buffer
To transmit photo images as JSON to a backend server (typical use case in enterprise apps), we want it to be in base64 encoded string format. To enable this conversion we first need to convert the photo file into an image buffer, as the encoding/decoding APIs expect a buffer.
It is strongly recommended to use an async pattern where possible, as all of this processing is happening inside the photo button click handler.
We access the photo file as a random access stream and copy it into a buffer using DataReader interface. Sample code is shown in Figure 10.
StorageFile photo = await dialog.CaptureFileAsync(CameraCaptureUIMode.Photo); if (photo == null) return; byte[] photoBuf = null; using (IRandomAccessStream photostream = await photo.OpenReadAsync()) { photoBuf = new byte[photostream.Size]; using (DataReader dr = new DataReader(await photo.OpenReadAsync())) { await dr.LoadAsync((uint)photostream.Size); dr.ReadBytes(photoBuf); } }
Figure 10: Sample code to convert the photo file into a buffer ++
Encoding and decoding image buffers into/from base64 encoded strings
We can use the Convert class in System namespace to encode and decode base64 format strings. In the previous section we discussed how to convert the photo image into a byte buffer, which we can use in base64 conversion APIs. The ToBase64String method is documented here:
The code snippet below shows how to convert the photoBuf buffer we created in the previous section into a base64 encoded string.
Pic = Convert.ToBase64String(photoBuf, 0, photoBuf.Length);
The variable “Pic” is a public member variable of the patient view model class we discussed earlier.
To convert the string back into a buffer:
var photoBuf = Convert.FromBase64String(pic);
Displaying the picture using Image Control and BitmapImage Binding
We can use the XAML Image control to display our photo. Please refer to the following document for more information:
The Image control is very flexible, allowing different image formats and options. For example, we can display our photo by binding to our patient view model, as shown below:
<Image Margin="0,40,20,0" DataContext="{Binding Patient}" Source="{Binding Image}"></Image>
The Source property on the Image control can automatically convert either a BitmapImage instance or even a direct source path to an image file. To dynamically update our image, it is convenient if we bind it to a BitmapImage instance. You can find more details on this class here:
To reiterate, it’s strongly recommended to use async methods where possible as these properties are bound to XAML UI elements.
BitmapImage gives us the option to directly use a URI or set our photo buffer as the input stream via the SetSourceAsync method. We use the SetSourceAsync method for generating the profile picture if available, or else a random avatar (from app assets) depending on patient gender. Please refer to the code snippet in figure 10 below.
public class PatientsViewModel : BindableBase { public PatientsViewModel() { this.PatientPicCmd= new DelegateCommand(DoPatientPicCmd); } private string pic = string.Empty; public string Pic { get { return pic; } set { this.SetProperty(ref pic, value); } } private BitmapImage image = null; public BitmapImage Image { get { if (image == null) GetImageAsync(); return image; } } public async Task GetImageAsync() { image = new BitmapImage(); if (pic.Length > 1) { var photoBuf = Convert.FromBase64String(pic); using (InMemoryRandomAccessStream mrs = new InMemoryRandomAccessStream()) { using (DataWriter dw = new DataWriter(mrs.GetOutputStreamAt(0))) { dw.WriteBytes(photoBuf); await dw.StoreAsync(); } await image.SetSourceAsync(mrs); } } else { Random rand = new Random(); String url = "ms-appx:///Assets/" + gender.ToLower() + rand.Next(1, 4).ToString() + ".png"; StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri(url)); using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read)) { await image.SetSourceAsync(fileStream); } } OnPropertyChanged("Image"); } … …
Figure 10: sample code for displaying a photo in an Image control using BitmapImage & SetSourceAsync ++
Pic string property stores the base64 encoded string that we converted from our camera photo file. This property can be persisted to a local database or transmitted to backend server. The “Image” property (of type BitmapImage), which we bind to our XAML image control, simply returns a BitmapImage depending on what is in the “Pic” variable. If it is empty, it returns a random avatar or else converts the “Pic” base64 string back into a byte buffer and returns a BitmapImage instance containing it.
Figure 11 shows the updated patients screen we referred to in Figure 1.
Figure 11: Updated patients UI page (captured from Windows* 8)
Users can click on any patient and update his/her profile picture, and the XAML binding will automatically update all references to it in Image controls.
Summary
We have discussed how iOS developers can port their camera-related code to Windows 8. We covered how to invoke the default camera UI control, process the result, use async programming patterns, and use the Image control to display the picture in Windows Store apps UI. We also covered how to encode and decode the picture to/from base64 format, which can then be easily transmitted as JSON data to RESTful backend services.
*Other names and brands may be claimed as the property of others.
++This sample source code is released under the Intel OBL Sample Source Code License (MS-LPL Compatible), Microsoft Limited Public License, and Visual Studio* 2012 License.
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https://software.intel.com/es-es/articles/camera-usage-and-features-from-ios-to-windows-8-store-app
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Hi everybody, fun.
Step 1: All What You Need
This is the list of all what I need to do my Photobooth:
- 1 Raspberry pi (for me Raspberry 1 model B because I've got it before but you can take a newer version)
- 1 SD Card for the raspberry
- 1 micro USB cable + power adapter 5V and 2A (to power raspberry)
- 1 Camera module for raspberry
- 1 USB Hub powered
- 1 photo printer compatible with raspbian (for me HP Photosmart 475)
- 1 massive arcade button 100mm with led
- 1 12v transformer for button led
- 1 PC screen (if it's not an HDMI screen you will need an HDMI adapter to plug to Raspberry)
- 3 spotlights with transformer
- 1 desk grommet of 80mm to fix the camera module
- Pieces of wood to make the box
- All decoration you want to embellish your Photobooth (for me pink wallpaper).
Step 2: Prepare Your Raspberry Pi
First of all you have to prepare your Raspberry pi and test all your installation with the program (I will give you my program don't worry ;)).
1. Load the OS of Raspberry pi into the SD card => Raspbian (Linux OS for Raspberry)
From your computer (windows / mac / linux):
- Download Raspbian with desktop from this page:
- Download Etcher and install it from this page:
- Connect an SD card reader with the SD.
You can find more information on this page:
2. Enable Camera module
To enable the camera module there is a little configuration to do:
3. Prepare Raspbian with all librairies you need
- Install Python (because program is made with Python), you will find how to do here:
- Install Pygame (library for python graphical interface), more information here:
- Install Picamera (library for the camera module of Raspberry pi):
- Install Python module RPI.GPIO (library for control Raspberry GPIO for the arcade button):
- Install CUPS to add a printer on Raspbian, you will find how to do here:
- Install PIL (library for images on Python):
Step 3: Wire Arcade Button on Raspberry Pi photobooth.
On the code you can change the path of the folder where pictures will be saved.
To run it you just have to launch a terminal, navagate to the program folder and type "sudo python camera.py"
If you want to test it without a button wire on GPIO Pin 25 of the raspberry, you can push down arrow of your keyboard.
Finally, I wanted to run the program at startup of the raspberry pi so I followed this tuto
The script which launch at startup is on the Github: photobooth-script.sh
Step 5: Make the Box
You will find here all step of construction of the box
41 Discussions
Question 5 weeks!
2 months 10 months 10 months ago
Hi,
I think you Forgot to install CUPS on your raspberry. It is explain on step 2 how to install it.
Reply 7 months ago
Same problem, I re installed everything and no luck
Reply 7 months ago
I thank I Forgot à step, installing cups for python. To do that open a terminal and type apt-get python-cups. I think this Step will solve your issue
Reply 7 months ago
I did install python cups but when i run the code it gives me a
Error
ImportError: No module named cups
I tried re-installing and no luck
Answer 10 months ago
No it's definitely not that as I said in my post I've installed cups. I've used cups to test the printer. But it's not recognising cups when running the camera.py code in terminal.
Reply 8 months ago
Hi,
I had the same problem resolved with the command sudo apt-get python-cups
because you need to install cups for python.
hope this helps if you didn't find the answer
Question 8 months ago
The photobooth module crashes when I go to press the button to print and nothing is sent to my printer. Do i need to make a configuration?
Answer 7 months ago
Its happening to me also, did you figure it out?
Question 10 months ago
Any recommendations for someone trying to do this without the printer?
Answer 10 months ago
Hi,
You can use my code but you have to modify it just a little bit to remove the printing part (remove from line 354 to line 392). Pictures will be saved on the raspberry pi.
Reply 8 months ago
hello where are they registered? and how are the photos recovered when the script is launched?
Question 8 months.
Answer 8 months ago
My button doesn't work?
Also when I use the arrow key to try printing. The whole thing freezes and I have to restart the pi.
Any ideas?
Question 10 months ago
hi , i have a problem with install when i try run : sudo python camera.py then i have :
pi@raspberrypi:~/Downloads/photoboothdiy-master $ sudo python camera.py
Traceback (most recent call last):
File "camera.py", line 6, in <module>
import cups
ImportError: No module named cups
Can you help me ?
Answer 8 months ago
Hi,
I had the same problem resolved with the command sudo apt-get python-cups
because you need to install cups for python.
hope this helps if you didn't find the answer
Answer 10 months ago
Hi MariuszC4 ,
I think you Forgot to install CUPS on your raspberry. It is explain on step 2 how to install it.
Question 8 months ago
I keep receiving the error...
ImportError: No module named cups
Any tips on how to resolve this?
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https://www.instructables.com/id/Wedding-Event-Photobooth/
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Dezi - REST search platform
Start the Dezi server, listening on port 5000:
% dezi -p 5000
Add a document foo to the index:
% curl -XPOST \ -d '<doc><title>bar</title>hello world</doc>' \ -H 'Content-Type: application/xml'
Search the index for bar:
% curl '' % curl ''
Read the usage statement:
% dezi -h
Dezi is a search platform based on Apache Lucy, Swish3, Search::OpenSearch and Search::Query.
Dezi integrates several CPAN search libraries into one easy-to-use interface.
This document is a placeholder for the namespace and documentation only. You should read:
Peter Karman,
<karman at cpan.org>
Many of the code ideas in Dezi were developed while working on search-related projects for the Public Insight Network at American Public Media..
Please report any bugs or feature requests to
bug-dezi,
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http://search.cpan.org/~karman/Dezi-0.002010/lib/Dezi.pm
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Hello all,
I have a doubt concerning to overloaded operators.
Does the compiler create new temporary object to the elements involved on the overloaded operation?
E.g. Operator + overloaded.
a = b + c;
Does the compiler creat temporary object for b and c?
See the following code and the print outs. When the + operator is called, 3 new objects are destroyed and I cant see the construction message.
I guess the default copy constructor is called by the compiler, but I am not sure.
Does any one knows the answer for this question???
Thank you,
Helbert
// Class1.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> using namespace std; class Rectangle{ int x, y; public: Rectangle(int x, int y); Rectangle(){cout << "Created: " << this << endl;}; void set_values(int x, int y); int getX() {return x;}; int getY() {return y;}; int area() {return (x*y); } Rectangle operator +(Rectangle); ~Rectangle(); }; Rectangle::Rectangle(int x, int y){ this->x = x; this->y = y; cout << "Created: " << this << endl; } Rectangle::~Rectangle(){ cout << "Retangle has been destroyed " << this << endl; } Rectangle Rectangle::operator +(Rectangle add){ Rectangle tmp; tmp.set_values(add.getX(), add.getY()); return tmp; } void Rectangle::set_values(int x, int y){ this->x = x; this->y = y; } int main(){ Rectangle rect(2,3); Rectangle rectb(1,2); Rectangle rectc; cout << "AREA: " << rect.area() << endl; cout << "AREA: " << rectb.area() << endl; rectc = rect + rectb; cout << "AREA: " << rectc.area() << endl; return 0; }
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https://www.daniweb.com/programming/software-development/threads/123596/operator-overload-question
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Synopsis
#include <gtk/gtk.h> GtkRuler; GtkRulerMetric; void gtk_ruler_set_metric (GtkRuler *ruler, GtkMetricType metric); void gtk_ruler_set_range (GtkRuler *ruler, gdouble lower, gdouble upper, gdouble position, gdouble max_size); GtkMetricType gtk_ruler_get_metric (GtkRuler *ruler); void gtk_ruler_get_range (GtkRuler *ruler, gdouble *lower, gdouble *upper, gdouble *position, gdouble *max_size);
Object Hierarchy
GObject +----GInitiallyUnowned +----GtkObject +----GtkWidget +----GtkRuler +----GtkHRuler +----GtkVRuler
Implemented Interfaces
GtkRuler implements AtkImplementorIface, GtkBuildable and GtkOrientable.
Properties
"lower" gdouble : Read / Write "max-size" gdouble : Read / Write "metric" GtkMetricType : Read / Write "position" gdouble : Read / Write "upper" gdouble : Read / WriteHRuler to learn how to create a new horizontal ruler. See GtkVRuler to learn how to create a new vertical ruler.
Details
GtkRuler
typedef struct _GtkRuler GtkRuler;
All distances are in 1/72nd's of an inch. (According to Adobe thats a point, but points are really 1/72.27 in.)
GtkRulerMetric
typedef struct { gchar *metric_name; gchar *abbrev; /* This should be points_per_unit. This is the size of the unit * in 1/72nd's of an inch and has nothing to do with screen pixels */ gdouble pixels_per_unit; gdouble ruler_scale[10]; gint subdivide[5]; /* five possible modes of subdivision */ } GtkRulerMetric;
This should be points_per_unit. This is the size of the unit in 1/72nd's of an inch and has nothing to do with screen pixels.
gtk_ruler_set_metric ()
void gtk_ruler_set_metric (GtkRuler *ruler, GtkMetricType metric);
This calls the GTKMetricType to set the ruler to units defined. Available units are GTK_PIXELS, GTK_INCHES, or GTK_CENTIMETERS. The default unit of measurement is GTK_PIXELS.
gtk_ruler_set_range ()
void gtk_ruler_set_range (GtkRuler *ruler, gdouble lower, gdouble upper, gdouble position, gdouble max_size);
This sets the range of the ruler.
gtk_ruler_get_metric ()
GtkMetricType gtk_ruler_get_metric (GtkRuler *ruler);
Gets the units used for a GtkRuler. See
gtk_ruler_set_metric().
Property Details
The
"max-size" property
"max-size" gdouble : Read / Write
Maximum size of the ruler.
Default value: 0
The
"metric" property
"metric" GtkMetricType : Read / Write
The metric used for the ruler.
Default value: GTK_PIXELS
Since 2.8
The
"position" property
"position" gdouble : Read / Write
Position of mark on the ruler.
Default value: 0
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http://www.manpagez.com/html/gtk/gtk-2.16.6/GtkRuler.php
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On Tue, 2009-06-30 at 13:46 -0700, Glenn Faden wrote: > > > >>> My personal question now is : why didn't I find it by myself ! :-) > >>> > >> Because it doesn't work. See: > >> > >> > >> > >> 1403 /* > >> 1404 * Cross-zone mount triggering is disallowed. > >> 1405 */ > >> 1406 if (fnip->fi_zoneid != getzoneid()) > >> 1407 return (EPERM); /* Not owner of mount */ > >> > > > > This place is easy to fix if you ask me. The real question is what kind > > of long lasting impact would allowing such a thing have. And this is > > a conversation I'm very interested in having. > > > > If this were easy it would have fixed already.
This depends of what "it" is. Your answer seems to be applicable to the original question. But it doesn't answer mine (hence a change of a subject line). Perhaps the answer to my question is -- it is a bad idea and it shouldn't be implemented. Fine. I still would like to know the reasons of why it might be considered a bad idea. So if is no to much to ask of this list -- I'd appreciated being educated on this subject. I'm also curious to know if what I'm requesting is reasonable but I should use a different "feature" to achieve what I want. To repeat *my* question: would it be possible to have a tunable parameter that would force all the FS traffic into a global zone the way this workaround does for NFS: Since all the processes running in zones are nothing but regular processes I would like to have an option of making their FS related requests behaving like ones. Per my explicit request, of course. > I think the following is what we really need: > > 1. Allow non-global zones to be NFS servers > > 2. Allow automounting between zones > > I had also tried (and failed) to implement a new kind of automap similar > to the existing entry > > /net -hosts > > but using zone names instead of hostnames: > > /zone -zones > > I implemented this for Trusted Extensions in 2005 but couldn't fix the > zone and automounter deadlocks, so it never go putback to OpenSolaris. Again, the above is all good and fine but it doesn't answer the question I asked (sorry -- I didn't change the subject before to avoid such a confusion). Thanks, Roman. _______________________________________________ zones-discuss mailing list zones-discuss@opensolaris.org
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https://www.mail-archive.com/zones-discuss@opensolaris.org/msg04801.html
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Notes for Package maintainers¶
If you are maintaining packages of software that uses pbr, there are some features you probably want to be aware of that can make your life easier. They are exposed by environment variables, so adding them to rules or spec files should be fairly easy.
Versioning¶
pbr, when run in a git repo, derives the version of a package from the git tags. When run in a tarball with a proper egg-info dir, it will happily pull the version from that. So for the most part, the package maintainers shouldn’t need to care. However, if you are doing something like keeping a git repo with the sources and the packaging intermixed and it’s causing pbr to get confused about whether its in its own git repo or not, you can set PBR_VERSION:
PBR_VERSION=1.2.3
and all version calculation logic will be completely skipped and the supplied version will be considered absolute.
Distribution version numbers¶
pbr will automatically calculate upstream version numbers for dpkg and rpm using systems. Releases are easy (and obvious). When packaging preleases though things get more complex. Firstly, semver does not provide for any sort order between pre-releases and development snapshots, so it can be complex (perhaps intractable) to package both into one repository - we recommend with either packaging pre-release releases (alpha/beta/rc’s) or dev snapshots but not both. Secondly, as pre-releases and snapshots have the same major/minor/patch version as the version they lead up to, but have to sort before it, we cannot map their version naturally into the rpm version namespace: instead we represent their versions as versions of the release before.
Dependencies¶
As of 1.0.0 pbr doesn’t alter the dependency behaviour of setuptools.
Older versions would invoke pip internally under some circumstances and required the environment variable SKIP_PIP_INSTALL to be set to prevent that. Since 1.0.0 we now document that dependencies should be installed before installing a pbr using package. We don’t support easy install, but neither do we interfere with it today. If you observe easy install being triggered when building a binary package, then you’ve probably missed one or more package requirements.
Note: we reserve the right to disable easy install via pbr in future, since we don’t want to debug or support the interactions that can occur when using it.
Tarballs¶
pbr includes everything in a source tarball that is in the original git repository. This can again cause havoc if a package maintainer is doing fancy things with combined git repos, and is generating a source tarball using python setup.py sdist from that repo. If that is the workflow the packager is using, setting SKIP_GIT_SDIST:
SKIP_GIT_SDIST=1
will cause all logic around using git to find the files that should be in the source tarball to be skipped. Beware though, that because pbr packages automatically find all of the files, most of them do not have a complete MANIFEST.in file, so its possible that a tarball produced in that way will be missing files.
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https://docs.openstack.org/developer/pbr/packagers.html
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.
(Python 3 is used for the duration of the article.)
The Global Interpreter Lock
It’s impossible to talk about concurrent programming in Python without mentioning the Global Interpreter Lock, or GIL. This is because of the large impact it has on which approach you select when writing asynchronous Python. The most important thing to note is that it is only a feature of CPython (the widely used “reference” Python implementation), it’s not a feature of the language. Jython and IronPython, among other implementations, have no GIL.
The GIL is controversial because it only allows one thread at a time to access the Python interpreter. This means that it’s often not possible for threads to take advantage of multi-core systems. Note that if there are blocking operations which happen outside Python, long-wait tasks like I/O for instance, then the GIL is not a bottleneck and writing a threaded program will still be all this is that if you need true parallelism and need to leverage multi-core CPUs, threads won’t cut it and you need to use processes. A separate process means a separate interpreter with separate memory, its own GIL, and true parallelism. This guide will give examples of both thread and process architectures.
The concurrent.futures module
The
concurrent.futures module is a well-kept secret in Python, but provides a uniquely simple way to implement threads and processes. For many basic applications, the easy to use
Pool interface offered here is sufficient.
Here’s an example where we want to download some webpages, which will be much quicker if done in parallel.
"""Download webpages in threads.""" import requests from concurrent.futures import ThreadPoolExecutor download_list = [ {'name': 'google', 'url': ""}, {'name': 'reddit', 'url': ""}, {'name': 'ebay', 'url': ""}, {'name': 'bbc', 'url': ""} ] def download_page(page_info): """Download and save webpage.""" r = requests.get(page_info['url']) with open(page_info['name'] + '.html', 'w') as save_file: save_file.write(r.text) if __name__ == '__main__': pool = ThreadPoolExecutor(max_workers=10) for download in download_list: pool.submit(download_page, download)
Most of the code is just setting up our downloader example; it’s only the last block which contains the threading-specific code. Note how easy it is to create a dynamic pool of workers using
ThreadPoolExecutor and submit a task. We could even simplify the last two lines to one using
map:
pool.map(download_page, download_list)
Using threads works well in this case since the blocking operation that benefits from concurrency is the act of fetching the webpage. This means that the GIL is not an issue and threading is an ideal solution. However, if the operation in question was something which was CPU intensive within Python, processes would likely be more appropriate because of the restrictions of the GIL. In that case, we could have simply switched out
ThreadPoolExecutor with
ProcessPoolExecutor.
The threading module
Whilst the
concurrent.futures module offers a great way to get off the ground quickly, sometimes more control is needed over different threads, which is where the ubiquitous
threading module comes in.
Let’s re-implement the website downloader we made above, this time using the
threading module.
"""Download webpages in threads, using `threading`.""" import requests import time import thread = threading.Thread(target=download_page, args=(download,)) downloader.start() status = threading.Thread(target=status_update) status.start()
For each thread we want to create, we make an instance of the
threading.Thread class, specifying what we would like our worker function to be, and the arguments required.
Note that we’ve also added a status update thread. The purpose of this is to repeatedly print “Still downloading” until we’ve finished fetching all the web pages. Unfortunately, since Python waits for all threads to finish executing before it exits, the program will never exit and the status updater thread will never stop printing.
This is an example of when the
threading module’s multitude of options could be useful: we can mark the updater thread as a daemon thread, which means that Python will exit when only daemon threads are left running.
status = threading.Thread(target=status_update) status.daemon = True status.start()
The program now successfully stops printing and exits when all downloader threads are finished.
Daemon threads are generally most useful for background tasks and repetitive functions which are only required when the main program is running, since a daemon can be killed at any moment, causing data loss.
The combination of threading and queues
So far we’ve only looked at cases where we know exactly what we want the threads to be working on when we start them. However, it’s often the case that mark tasks as done is as simple as this:
from queue import Queue # maxsize=0 means infinite size limit tasks = Queue(maxsize=0) tasks.put("a task") tasks.put("another task") while not tasks.empty(): print(tasks.get()) # execute task tasks.task_done()
Ok, that’s pretty basic so far. Now let’s use it to create a tasks queue for our website downloader. We’ll create a group of worker threads which can all access the queue and wait for tasks to come in.
"""Download webpages in threads, using `threading` and `queue`.""" import requests import threading from queue import Queue NUM_WORKER_THREADS = 3 def download_page(page_info): """Download and save webpage.""" r = requests.get(page_info['url']) with open(page_info['name'] + '.html', 'w') as save_file: save_file.write(r.text) def handle_tasks(tasks_queue): """Monitor tasks queue and execute tasks as appropriate.""" while True: download_page(tasks_queue.get()) tasks_queue.task_done() if __name__ == '__main__': tasks = Queue(maxsize=0) # Create and start worker threads for i in range(NUM_WORKER_THREADS): worker = threading.Thread(target=handle_tasks, args=(tasks,)) worker.daemon = True worker.start() # Add some tasks to the queue tasks.put({'name': 'google', 'url': ""}) tasks.put({'name': 'reddit', 'url': ""}) tasks.put({'name': 'ebay', 'url': ""}) tasks.put({'name': 'bbc', 'url': ""}) tasks.join()
Note that in this example all the tasks were added in one go for the sake of brevity, but in a real application the tasks could trickle in at any rate. Here we exit the program when the tasks queue has been fully completed, using the
.join() method.
The multiprocessing module
The
threading module is great for detailed control of threads, but what if we want this finer level of control for processes? You might think that this would be more challenging since once a process is launched, it’s completely separate and independent – harder to control than a new our examples above. Our simple downloader would become this:
"""Download webpages in threads, using `multiprocessing`.""" import requests import time import multiprocess = multiprocessing.Process(target=download_page, args=(download,)) downloader.start() status = multiprocessing.Process(target=status_update) status.daemon = True status.start()
We think it’s awesome that Python manages to keep the same syntax between the
threading and
multiprocessing modules, when the action taking place under the hood is so different.
When it comes to distributing data between processes, the
queue.Queue that we used for threading will not work send it through a pipe between processes – a very convenient abstraction.
Summary
Writing concurrent code in Python can be a lot of fun due to the inbuilt language features that abstract away a lot of problems. This doesn’t mean that a detailed level of control cannot be achieved either, but rather that the barrier to getting started with simple tasks is lowered. So when you’re stuck waiting for one process to finish before starting the next, give one of these techniques a try.
7 thoughts on “Thread Carefully: An Introduction To Concurrent Python”
A little bit sad to not see asyncio in there.
asyncio is great, the only reason I didn’t include it is that it’s an inherently different architecture to the modules used here; these are basic introductory examples where you mostly don’t need to do anything fancy. Asyncio may make an appearance in future!
Non-blocking; that is, concurrency ? Probably multiprocessing if you have the correct hardware. But for doing in code and if you are using sleep, then asyncio is the most obvious and straight -forward solution. You do know that multiprocessing, asyncio, and threading libs all use a different scheduler?
Everyone criticizes the GIL. The GIL was the secret that both Luke and Neo sought. The GIL explains the failed quest for human meaning in a vast uncaring universe. It is all an illusion. We are but an abstracted class of many illusory methods that are rendered for a non-existent (time) slice of a virtual existence.
[img][/img]
Python? Don’t thread on me.
Excellent post and it has been very helpful to me. But I’m faced with a challenge to execute two independent functions, totally unrelated and I can’t do that. I have both functions working perfectly in series, but when I try to parallelize them, using pool or threading (as proposed here) they continue running in series. Could you help me with a post or a clue about parallelization of at least two independent functions, please?
Hi, glad to hear you found it useful. It depends what you’re trying to do with them, but a good start might be the multiprocessing module or concurrent.futures.ProcessPoolExecutor, since it sounds like you want to be using processes instead of threads.
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https://hackaday.com/2018/12/18/thread-carefully-an-introduction-to-concurrent-python/
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The ODROID is a series of single-board computers manufactured by Hardkernel in South Korea. The ODROID-C1+ ($35) and the ODROID-C2 ($46) have a form factor similar to the Raspberry Pi 3. The higher end ODROID-XU($59) which is around 5 times faster than the Pi 3 has a signifigently different board layout.
For my testing I looked at the ODROID-C2 ($46), it is a little more expensive than a Pi 3 but the literature states that it’s 2-3 times faster.
My goal was to see if I could use the ODROID-C2 for some typical Raspberry Pi applications. In this blog I will be looking at doing C, Python and NodeRed programming from a Pi user perspective.
I’ve been happy with the functionality and openness of the Raspberry Pi platform, however I find its desktop performance to be sluggish. For only a few dollars more than a Pi 3 the ODROID-C2 CPU, RAM and GPU specs are impressive.
First Impressions
The ODROID-C2 is almost the same footprint as the Raspberry Pi 3 but not exactly. I found that because the microSD mounting is different some, but not all, of my Pi cases could be used .
When you are designing your projects it is important to note that the ODROID-C2 does not have a built in Wifi or Bluetooth adapters, so you’ll need wired connections or USB adapters. Like some of the Orange Pi modules the ODROID-C2 has a built-in IR connection.
ODROID-C2 can be loaded with Ubuntu, Arch Linux and Android images. For my testing I used the Armbian 5.40 Ubuntu desktop and the performance was signifigently faster than my Raspberry Pi 3 Raspian desktop. I could definitely see ODROID-C2 being used as a low cost Web browser station.
The ODROID-C2 images are quite lean, so you will need to go the ODROID Wiki,, for instructions on loading additional software components.
The ODROID-C2 has a 40 pin General Purpose Input/Output (GPIO) arrangement like the Pi 3, so it is possible to use Pi prototyping hats on the ODROID-C2 .
There are some noticeable differences in the pin definitions between the two modules, so for this reason I didn’t risk using any of my intelligent Pi hats on the ODROID-C2. The gpio command line tool can be used to view the pin definitions:
The Raspberry Pi GPIO names are in the range of 2 to 27, whereas the ODROID-C2 GPIO ranges are in the 200’s, because of this don’t expect to be able to run all your Raspberry Pi code “as is” on the ODROID-C2.
Unlike the Arduino the Raspberry Pi platform has no built in support for analog inputs. I got pretty excited when I noticed that the ODROID-C2 had two built in Analog-to-Digital Converter (ADC) pins (AIN.1 on pin 37 and AIN.0 on pin 40). However after some investigation I found that these pins had virtually no example code and they only support 1.8 volts. Most of my analog input sensors require 3.3V or 5V so I’m not sure how often these ADC pins will be used.
Python Applications
The ODROID-C2 Wiki references the RPi.GPIO and wiringpi Python libraries. I tested both of these libraries and I found that standard reads and writes worked, but neither of these libraries supported the callback functions like the Raspberry Pi versions.
For existing Pi projects where you are using callback functions for rising and/or falling digital signals (like intrusion alarms) you will need to do some re-coding with a polling method. It’s also important to note that the ODROID RPi.GPIO library is a little confusing because it uses the Pi pin names and not the ODROID pin names, so for example ODROID-C2 physical pin 7 is referenced as GPIO.04 (as on a PI) and not GPIO.249 (the ODROID-C2 name). Below is simple Python example that polls for a button press and then toggles an LED output when a button press is caught.
import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) button = 4 # physical pin 7, PI GPIO.04, ODROID-C2 GPIO.249 led = 17 # physical pin 11, PI GPIO.17, ODROID-C2 GPIO.247 GPIO.setup(led, GPIO.OUT, initial=GPIO.LOW) GPIO.setup(button, GPIO.IN, pull_up_down = GPIO.PUD_UP) print ('Wait for button...') while True: if GPIO.input(button) == 1: GPIO.output(led,0) else: GPIO.output(led,1) print "button pressed"
There are some excellent Python libraries that are designed to work with the Raspberry Pi. However it will require some trial and error to determine which libraries will and won’t work with the ODROID-C2.
I tried testing the DHT11 temperature and humidity sensor with the ODROID-C2, and unfortunately the library had a “Segmentation Error” when I tried running an example.
Node-Red
NodeRed can be installed on ODROID-C2 by using the manual install instructions for Raspbian at nodered.org. This install procedure will add a start item to the desktop Application menu, but due to hardware differences the Raspberry Pi GPIO input/output components will not load.
To read and write to Raspberry Pi GPIO a simple workaround is to use exec nodes to call the gpio utility.
The command line syntax for writing a gpio output is: gpio write pin state, and for reading it is: gpio read pin. One of the limitations of this workaround is that you will need to add a polling mechanism, luckily there are some good scheduling nodes such as Big Timer that can be used.
C Applications
Programming in C is fairly well documented and an ODROID “C Tinkering Kit” is sold separately. The wiringPi library is used in C applications.
Below is a C version of the Python example above. It is important to note that these 2 examples talk to the same physical pins but the C wiringPi library uses the ODROID-C2 wPi numbers and the Python RPi.GPIO library uses the Pi BCM numbers.
// led.c - Read/Write "C" example for an Odroid-C2 // #include <wiringPi.h> int main(void) { wiringPiSetup(); int led = 0; int button = 7; pinMode(led, OUTPUT); pinMode(button, INPUT); for (;;) { if (digitalRead(button) == 1) { digitalWrite(led, LOW); } else { digitalWrite(led, HIGH); } } return 0; }
To compile and run this program:
$ gcc -o led led.c -lwiringPi -lpthread $ sudo ./led
Summary
I liked that I could reuse some of my Pi cases and prototyping hats with the ODROID-C2.
As a PI user I found that coding in C, Python and NodeRed on the ODROID-C2 was fairly easy, but there were many limitation compared to the Pi platform. The ODROID Wiki had the key product documentation, but it was no where near the incredibly rich documentation that exists with Raspberry Pi modules.
There are a some excellent Python libraries and PI hardware add-ons that support a variety of sensors and I/O applications, these may or not work with the ODROID hardware.
During the development cycle of a project it is nice to have a faster interface, but typically my final projects do not need any high end processing and they can often run on low end Raspberry Pi 1 modules. So for now I would stick to a Raspberry Pi for GPIO/hardware type projects.
I enjoying playing with the ODROID-C2 and for projects requiring higher performance such as video servers, graphic or Web applications then the ODROID-C2 module is definitely worth considering.
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Installing S50N and S50V Systems Notes, Cautions, and Warnings NOTE: A NOTE indicates important information that helps you make better use of your computer. CAUTION: A CAUTION indicates potential damage to hardware or loss of data if instructions are not followed. WARNING: A WARNING indicates a potential for property damage, personal injury, or death. Information in this publication is subject to change without notice. © 2010 Dell Force10. All rights reserved. Reproduction of these materials in any manner whatsoever without the written permission of Dell Inc. is strictly forbidden. Trademarks used in this text: Dell™, the DELL logo, Dell Precision™, OptiPlex™, Latitude™, PowerEdge™, PowerVault™, PowerConnect™, OpenManage™, EqualLogic™, KACE™, FlexAddress™ and Vostro™ are trademarks of Dell Inc. Intel®, Pentium®, Xeon®, Core™ and Celeron® are registered trademarks of Intel Corporation in the U.S. and other countries. AMD® is a registered trademark and AMD Opteron™, AMD Phenom™, and AMD Sempron™ are trademarks of Advanced Micro Devices, Inc. Microsoft®, Windows®, Windows Server®, MS-DOS® and Windows Vista® are either. Citrix®, Xen®, XenServer® and XenMotion® are either registered trademarks or trademarks of Citrix Systems, Inc. in the United States and/or other countries. VMware®, Virtual SMP®, vMotion®, vCenter®, and vSphere® are registered trademarks or trademarks. November 2011 P/N 101-00059-03 Contents 1 About this Guide Information Symbols and Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 System Overview Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 System Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 LED Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3 Site Preparations Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Cabinet Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Rack Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Fans and Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 S50N-DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 S50N and S50V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Power over Ethernet (PoE) Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Storing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Tools Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4 Installing the Switch Inserting Optional Modules (10-Gigabit or Stacking) . . . . . . . . . . . . . . . . . . . . . . . . 17 Installing the System on a Tabletop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Installing the System in a Rack or Cabinet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Two-Post Rack Mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Four-Post Rack-mounting with Threaded Rails . . . . . . . . . . . . . . . . . . . . . . . . . 19 Four-Post Rack-mounting with Cage Nuts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Stacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Using SFTOS Stacking Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Using FTOS Stacking Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Connecting Stack Ports (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Supplying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 S50N-DC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5 Installing Backup Power Backup Power Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Contents | 3 | support.dell.com The Power Connections on the Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Installing the Backup DC Power Supply for the S50V. . . . . . . . . . . . . . . . . . . . . . . . 30 Inserting Tandem S50V PSUs into a Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Connecting the S50V DC-to-DC Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Installing the Backup DC Power Supply for the S50N . . . . . . . . . . . . . . . . . . . . . . . 34 DC Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Installing the External Power Shelf (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Inserting an S50N PSU into the EPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Connecting the DC-to-DC Cable for the S50N PSU . . . . . . . . . . . . . . . . . . . . . 37 6 Installing Ports Accessing the Console Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Connecting S50V Ethernet Ports with PoE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Installing Optics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Installing SFPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Installing XFPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 7 Switch Specifications Chassis Physical Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Environmental Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Power Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 AC Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 DC Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Agency Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Safety Standards and Compliance Agency Certifications . . . . . . . . . . . . . . . . . 51 Electromagnetic Compatibility (EMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Product Recycling and Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 8 Technical Support The iSupport Website . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Accessing iSupport Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Contacting the Technical Assistance Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Locating Serial Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Requesting a Hardware Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Index 4 | Contents 1 About this Guide This guide provides site preparation recommendations, step-by-step procedures for rack mounting and desk mounting the S50V or S50N switches (and related models, such as S50N-DC), inserting optional modules, and connecting to a power source. Except where noted, descriptions and instructions in this guide apply to all variants of these switches. After you have completed the hardware installation and power-up of the switch, refer to the SFTOS™ Configuration Guide for software configuration information and to the SFTOS™ Command Reference for detailed Command Line Interface (CLI) information. Information Symbols and Warnings The following graphic symbols are used in this document to bring attention to hazards that exist when handling the switch and its components. Please read these alerts and heed their warnings and cautions. Table 1-1 describes symbols contained in this guide. Table 1-1. Symbol Information Symbols Warning Description Note This symbol informs you of important operational information. Caution This symbol informs you that improper handling and installation could result in equipment damage or loss of data. Warning This symbol signals information about hardware handling that could result in injury. WARNING: The installation of this equipment shall be performed by trained and qualified personnel only. Read this guide before installing and powering up this equipment. This equipment contains two power cords. Disconnect both power cords before servicing. WARNING: Class 1 laser product. Attention: Produit laser de classe 1 Warnung: Laserprodukt der Klasse 1 About this Guide | 5 | support.dell.com WARNING: This equipment contains optical transceivers, which comply with the limits of Class 1 laser radiation. Visible and invisible laser radiation may be emitted from the aperture of the optical transceiver ports when no cable is connected. Avoid exposure to laser radiation and do not stare into open apertures. WARNING: Building Supply Notice for AC Power Supply Use. This product relies on the building's installation for short-circuit (overcurrent) protection. Ensure that a fuse or circuit breaker no larger than 120 VAC, 15A U.S. (240 VAC, 10A international) is used on the phase conductors (all current-carrying conductors). Attention: Pour ce qui est de la protection contre les courts-circuits (surtension), ce produit dépend de l'installation électrique du local. Vérifier qu'un fusible ou qu'un disjoncteur de 120 V alt., 15 A U.S. maximum (240 V alt., 10 A international) est utilisé sur les conducteurs de phase (conducteurs de charge). Warnung: Dieses Produkt ist darauf angewiesen, daß im Gebäude ein Kurzschluß- bzw. Überstromschutz installiert ist. Stellen Sie sicher, daß eine Sicherung oder ein Unterbrecher von nicht mehr als 240 V Wechselstrom, 10 A (bzw. in den USA 120 V Wechselstrom, 15 A) an den Phasenleitern (allen stromführenden Leitern) verwendet wird. WARNING: Building Supply Notice for DC Power Supply Use. An external disconnect must be provided and be easily accessible. Dell Force10 recommends the use of a 60A circuit breaker. ATTENTION: Un interrupteur externe doit être fournis et doit être facilement accessible. Dell Force10 recommande l'utilisation d'un disjoncteur de 60Ampères. WARNUNG: Eine leicht zugängliche Tren Dell Force10 nvorrichtung muss in der Verdrahtung eingebaut sein. Dell Force10 empfiehlt einen 60A Sicherungsautomaten zu benutzen CAUTION: Wear grounding wrist straps when handling this equipment to avoid ESD damage. CAUTION: Earthing (AKA grounding) connection essential before connecting supply. Always make the ground connection first and disconnect it last. CAUTION: Disposal of this equipment should be handled according to all national laws and regulations. See Product Recycling and Disposal on page 52. CAUTION: This unit has more than one power supply connection; all connections must be removed to remove all power from the unit. ATTENTION: Cette unité est équipée de plusieurs raccordements d'alimentation. Pour supprimer tout courant électrique de l'unité, tous les cordons d'alimentation doivent être débranchés. WARNUNG: Diese Einheit verfügt über mehr als einen Stromanschluß; um Strom gänzlich von der Einheit fernzuhalten, müssen alle Stromzufuhren abgetrennt sein. CAUTION: Lithium Battery Notice. Danger of explosion if battery is replaced with incorrect type. Replace only with the same type recommended by the manufacturer. Dispose of used batteries according to the manufacturer's instructions. ACHTUNG - Explosionsgefahr wenn die Battery in umgekehrter Polarität eingesetzt wird. Nur miteinem gleichen oder ähnlichen, vom Hersteller empfohlenen Typ, ersetzen. Verbrauchte Batterien müssen per den Instructionen des Herstellers verwertet werden. ATTENTION - Il y a danger d'explosion s'il. NOTE: Other cautionary statements appear in context elsewhere in this book. 6 | About this Guide Related Publications The S50V or S50N (and related models, such as S50N-DC) can run on either FTOS or SFTOS. Depending on which software your system contains, refer to the following documents: Table 1-2. Documentation FTOS Documentation SFTOS Documentation FTOS Configuration Guide for the S-Series SFTOS Configuration Guide FTOS Command Reference for the S-Series SFTOS Command Reference S-Series and FTOS Release Notes S-Series and SFTOS Release Notes S25P Quick Reference The Technical Documentation CD-ROM contains the S-Series hardware guides and the FTOS and SFTOS files listed above, respectively, except for the Release Notes. The CD-ROMs also have: • MIBs: Files for all SNMP MIBs supported by the software • Data sheets: Links to Dell Force10 product data sheets NOTE: Documentation CD-ROMs do not have software. For the most recent documentation and software, please visit iSupport (registration for access to some sections is required): CSPortal20/Main/SupportMain.aspx NOTE: The iSupport website also has a section for S-Series techtips and FAQs. About this Guide | 7 8 | About this Guide | support.dell.com 2 System Overview The S50V and S50N models of the Dell Force10 S-Series are stackable, Layer 2 switch/Layer 3 routers with 48 built-in 10/100/1000 Base-T ports, four SFP ports, and up to four optional 10-Gigabit (10GbE) ports (XFP or CX4), in two expansion slots. Figure 2-1 shows the front panel of the S50V. The S50N has the same layout; just the catalog number differs. The S50N-DC (see Figure 3-1 on page 15) differs only in that DC1 and DC2 status LEDs appear where the AC and DC status LEDs are on the S50V and S50N. Figure 2-1. The S50V Front View Status Panel LEDs Stack ID Indicator LED OK Alarm AC DC XFP49 XFP51 XFP51 XFP52 Link/Active Indicator LEDs (SFP Ports 45-48) Catalog # (S50-01-GE-48T-V) Alarm AC S50-01-GE-48T-V DC XFP49 51 XFP50 P52 fn00157s50V Stack ID RJ-45 Console Port Figure 2-2. Ethernet Ports (10/100/1000) Shared 10/100/1000 Ports (45-48) SFP Ports (45-48) The S50V Rear View Label (Part #, Serial #, MAC Address, Bar Code, FRU #) 10-Gigabit Modules or Stacking Modules (optional). Optical ports numbered from left to right. DC Power 11.5 -48V Current Ethernet Port Numbers 49 to 52, Right to Left Ground Connector fn00158s50V FG RTN -48V Sharing AC Power Receptacle The rear of the S50N differs only in that its DC terminal block has a different lug arrangement, as shown in Figure 3-1 on page 15, while the S50N-DC replaces the AC receptacle with a second DC terminal block. System Overview | 9 | support.dell.com Equipment The following items are necessary to install the system: • The switch • At least one grounded AC or DC power source per S50V or S50N switch; one or two grounded DC power sources per S50N-DC switch. • Cable (included) to connect the AC power source to the switch • Brackets for rack installation (included) • Screws for rack installation (included) and #2 Phillips screwdriver (not supplied) Other optional components are: • Stacking cables for connecting switches when stacked (not supplied). See Connecting Stack Ports (optional) on page 25. • Backup DC Power Module (see Chapter , Installing Backup Power, on page 29) • Optical networking components (see Chapter , Installing Ports, on page 41) • Stacking components (see Ports, below) Features • Internal power supply with power redundancy from built-in 1+1 AC/DC (AC: 110v/220v auto-detect; DC: -48V standards-based with terminal-type connectors). The one difference between the S50V and S50N is that the S50V has built-in support for 360W Power over Ethernet (PoE) — IEEE 802.3af — with power allocation control available through the CLI. • 256MB RAM and 32MB internal Flash memory • Supports up to 32000 MAC address entries, with hardware-assisted aging • Stackable switch features • 19-inch rack-mountable and standard 1U chassis height • Six built-in fans with automatic speed adjustment for temperature changes • Supports 9252-byte jumbo frames in FTOS, 9216-byte jumbo frames in SFTOS • Back-pressure support at half-duplex, IEEE 802.3x flow control at full duplex • Extensive LED system with per-port LEDs Ports • 48 fixed 10/100/1000 Mbps auto-sensing and auto-MDIX RJ45 ports, up to 15.4W PoE each • Four ports capable of using 10/100/1000 Base-T or 1000 Base-X using auto-media detect • Console port (see Chapter , Installing Ports, on page 41): Supplied with console cable (straight-through Ethernet copper cable) and terminal adapter (DB-9 to RJ-45) 10 | System Overview • Expansion slots that accept any combination of the following optional, high-capacity uplink modules: 10GbE XFP (two ports), 10GbE CX4 (two ports), 12G stacking (two ports) or 24G stacking (one port). See Inserting Optional Modules (10-Gigabit or Stacking) on page 17 and Connecting Stack Ports (optional) on page 25. System Status Chassis status information can be derived in several ways, including physical LED displays and boot menu options, both discussed here, along with CLI show commands, and SNMP traps. For details on those options, see the Command Reference and Configuration Guide for your software (FTOS or SFTOS). LED Displays As shown in Figure 2-2 on page 9, the front panel of the switch contains several sets of LEDs: • Stack ID: This is the LED at the far left of the front panel labeled “STACK ID”. See Stack ID in Table 2-2 on page 12). For more on stack unit numbering, see Stacking on page 23. • Status indicator LEDs on the left side of the front panel, to the right of the Stacking LED. See Table 2-2. • Each port has status indicator LEDs, described in Table 2-1. Table 2-1. Port LED Displays Feature Description 10/100/1000 Port LED* Speed LED (left side of each port) Green — 1000M Amber — 100M Off — 10M Link/Active LED (right side of each port) Green — Link up on this port Blinking Green — Activity, transmitting or receiving packet at this port. Amber — Link up and power supplied on this port Off — No Link detected at this port SFP Port LED* Link/Activity LED Green — Link up on this port Blinking Green — Activity, transmitting or receiving packet in link up state Off — No Link detected at this port XFP Port LED Link/Activity LED (Each XFP port has a status LED on the module and in the Status Display at the left front of the switch) Green — Link up on this port Blinking Green — Activity, transmitting or receiving packet in link up state Off — No Link detected at this port * The LEDs for a 10/100/1000 port numbered 45 through 48 are inactive if the shared SFP port (also labeled 45 through 48) is enabled. System Overview | 11 | support.dell.com NOTE: As suggested by the footnote above, the fiber SFP ports have priority over the four 10/100/1000 ports with the same number. The following table describes the LED status indicators on the left side of the front panel. Table 2-2. Status Panel LED Display Label LED Color Description Left Side of the Status Panel OK Green Off Green Blinking Amber Unit is online. Unit is powered off. Unit is booting up. (blinking rate is 16 Hz) Error during boot-up. AC (on the S50V and S50N) DC1 (on the S50N-DC) Green Amber Off Power supply is present and OK. Power supply is present but failed. Power supply is not present. XFP49* Green Blinking Green Off A valid 10G link is established on the port. Transmitting or receiving packets on the port. No link is established on the port. XFP50* Green Blinking Green Off A valid 10G link is established on the port. Transmitting or receiving packets on the port. No link is established on the port. STACK ID Green Indicates the stack ID (sometimes called "switch ID") of the unit. Starting with FTOS 7.8.1.0: • “A” is displayed to the left of the stack ID if the unit is a standalone or master (management) unit. • “B” is displayed for a standby unit. (Actually, it’s an 8, because of the limitations of the 7-segment LED.) • “0” is displayed next to the stack ID, as before, for the other units. Right Side of the Status Panel Alarm Amber Red Off Minor alarm: Fan or temperature is operating outside parameters. Major alarm No alarm DC (on the S50V and S50N) DC2 (on the S50N-DC) Green Amber Off Power supply is present and OK. Power supply is present but failed. Power supply is not present. XFP51* Green Blinking Green Off A valid 10G link is established on the port. Transmitting or receiving packets on the port. No link is established on the port. XFP52* Green Blinking Green Off A valid 10G link is established on the port. Transmitting or receiving packets on the port. No link is established on the port. *The four XFP LEDs on the front panel also indicate the status when CX4 ports are installed in the bay. 12 | System Overview 3 Site Preparations This chapter describes requirements and procedures to install your system in the following topics: • Site Selection • Cabinet Placement on page 13 • Rack Mounting on page 14 • Fans and Airflow on page 14 • Power on page 14 • Storing Components on page 16 • Tools Required on page 16 For detailed switch specifications, refer to Chapter , Switch Specifications, on page 47. NOTE: Install the switch into a rack or cabinet before installing any optional components. Site Selection Make sure that the area where you install your switch meets the following safety requirements: • Near an adequate power source. Connect the system to the appropriate branch circuit protection as defined by your local electrical codes. See cautions in Information Symbols and Warnings on page 5. • Environmental temperature between 32° – 122°F (0° – 50°C). • Relative humidity that does not exceed 85% non-condensing. • In a dry, clean, well-ventilated and temperature-controlled room, away from heat sources such as hot air vents or direct sunlight. • Away from sources of severe electromagnetic noise. • Positioned in a rack, cabinet, or on a desktop with adequate space in the front, rear, and sides of the unit for proper ventilation, and access. Cabinet Placement The cabinet must meet the following criteria: • Minimum cabinet size and airflow are according to the EIA standard. • Minimum of 5 inches (12.7 cm) between the side intake and exhaust vents and the cabinet wall. Site Preparations | 13 | support.dell.com Rack Mounting When you prepare your equipment rack, ensure that the rack is earth ground. The equipment rack must be grounded to the same ground point used by the power service in your area. The ground path must be permanent. Fans and Airflow Ventilation is side-to-side, with six fans on the left side of the switch. For proper ventilation, position the switch in an equipment rack (or cabinet) with a minimum of five inches (12.7 cm) of clearance around the side intake and exhaust vents. When two S-Series systems are installed side by side, position the two chassis at least 5 inches (12.7 cm) apart to permit proper airflow. The acceptable ambient temperature ranges are listed in Environmental Parameters on page 48. As listed in Table 2-2 on page 12, the front panels of the S50N and S50V series have an Alarm status LED, which is green when the switch is operating within required temperature parameters and all components are operating normally, including fans. The LED is amber when the temperature or components are outside expected parameters, red in a major alarm. The fan speed increases when the temperature reaches 72 degrees C, and decreases to normal speed when the temperature falls to 57 degrees C. The switch never intentionally stops managing traffic. SFTOS logs a temperature warning message when a temperature of 77 degrees C is reached, and logs another message when the temperature returns to normal. The Command Line Interface (CLI) also reports an alarm. Use the show logging command to see the log messages. For details, see the System Logs chapters of the SFTOS Command Reference and SFTOS Configuration Guide. In a stack, each unit has its own temperature monitoring and control. Status logging is identified by unit in the system log. Fan replacement in the field is not offered as an option. Power S50N-DC As shown below, the right side of the S50N-DC contains two terminal blocks for two 150W DC power supply inputs. The terminal blocks are labeled DC1 and DC2, which corresponds to the labels of the status LEDs on the front left of the switch. When both blocks are connected, they act in load-sharing mode with backup capability (one power supply can run the whole system). 14 | Site Preparations Figure 3-1. The S50N-DC Rear View Label (Part #, Serial #, MAC Address, Bar Code, FRU #) 10-Gigabit Modules or Stacking Modules (optional). Optical ports numbered from left to right. DC2 Ethernet Port Numbers 49 to 52, Right to Left Ground Connector -48V -48V FG RTN fn00158s50N-DC -48V -48V FG RTN DC1 S50N and S50V CAUTION: The power supply cord is used as the main disconnect device; ensure that the socket-outlet is located/installed near the equipment and is easily accessible. As shown in Figure 2-2 on page 9, the rear of the S50N and S50V models have both an auto-sensing 110/ 220V AC receptacle and a standard -48V terminal-type DC connector. The rear of an S50N differs only in the arrangement of the lugs on its DC terminal block (Figure 3-1). Each system ships only with the AC power cord. There is no power switch. Connecting the switch to either an AC or DC power source starts the switch. On both the S50N and S50V, either the AC or DC power supplies alone are sufficient to power the switch. When both AC and DC power supplies are connected, they act in roughly a 60%/40% load-sharing mode. On the S50V, when the Dell Force10 470W DC Backup Power Supply is connected to the Current Sharing connection on the S50V DC terminal block, the switch uses the DC and AC power supplies in current-sharing (load-sharing plus additive) mode, so that the total capability is 470W+470W = 940W. See Backup Power Components on page 29. Dell Force10 also offers an external 180W DC power supply for the S50N and S50N-DC models, the same power supply used by the S50. However, the connections differ from those on the S50, so the power supply ships with DC cables to support each model. Rack-mounting hardware is supplied. For details on connecting to a power source, see Supplying Power on page 27. Power over Ethernet (PoE) Support Along with the optional DC power supply noted above, the S50V includes an internal 470W power supply that supports both the operation of the switch and an independent power distribution system to supply power to the 48 copper Ethernet ports, supporting the IEEE 802.3af standard for Power over Ethernet (PoE). Connect only powered devices that adhere to IEEE 802.3af. Site Preparations | 15 | support.dell.com The total PoE power budget for the switch is between 320W and 790W, depending on the power sources available. If the external 470W Redundant Power Supply (catalog # S50-01-PSU-V) from Dell Force10 is attached to the Current Sharing terminal (see Chapter , Installing Backup Power, on page 29), you can use the power-budget command in FTOS to convert the power supply to current-sharing mode to provide up to 790W of PoE. When running SFTOS, use the inlinepower threshold command. Each port can provide a maximum of 15.4W, subject to the power budget, voltage, power priority, and power limit settings. PoE is, by default, enabled globally on a first-come, first-serve basis, until it exceeds the total available power. Alternatively, the switch administrator can use the CLI to allocate power on a per-port and a per-stack-unit basis, with per-port power limits and port prioritization. For a brief introduction in this guide to the PoE commands, see Connecting S50V Ethernet Ports with PoE on page 42. For details, see the PoE Commands sections in the Command Reference and Configuration Guide for your software. Storing Components If you do not install your system and components immediately, Dell Force10 recommends that you properly store the switch and all optional components until you are ready to install them. WARNING: Electrostatic discharge (ESD) damage can occur when components are mishandled. Always wear an ESD-preventive wrist or heel ground strap when handling the switch and its accessories. After you remove the original packaging, place the switch and its components on an antistatic surface. Follow these storage guidelines: • Storage temperature should remain constant, in the range from -40° to 158° F (-40°C to 70° C). • Storage humidity should be within 10 to 90% (relative humidity), non-condensing • Store on a dry surface or floor, away from direct sunlight, heat, and air conditioning ducts. • Store in a dust-free environment. Tools Required S-Series switches are shipped fully assembled, encased in foam. A utility knife is useful for cutting the packing tape, and a Phillips #2 screwdriver is required for attaching rack screws, and is also used for making some attachments, including DC cables and rear cover plates. Wear an anti-static guard, as noted above. 16 | Site Preparations 4 Installing the Switch To install S50V or S50N systems, Dell Force10 recommends that you complete the installation procedures in the order presented in this chapter: • Inserting Optional Modules (10-Gigabit or Stacking) • Installing the System on a Tabletop on page 18 • Installing the System in a Rack or Cabinet on page 19 • Stacking on page 23 • Supplying Power on page 27 WARNING: As with all electrical devices of this type, take all the necessary safety precautions to prevent injury when installing this system. Electrostatic discharge (ESD) damage can occur if components are mishandled. Always wear an ESD-preventive wrist or heel ground strap when handling the switch and its components. See other relevant cautions in the Preface. Inserting Optional Modules (10-Gigabit or Stacking) The S50V (catalog number S50-01-GE-48T-V) and S50N (catalog number S50-01-GE-48T-AC for ACpowered version of S50N; S50-01-GE-48T-DC for S50N-DC) have two expansion slots in the back of the chassis, for which there are four modules available: Module Description Catalog Number 2-port 10GbE XFP (optical connection) S50-01-10GE-2P 2-port 10GbE CX4 (copper connection) S50-01-10GE-2C 2-port 12GbE Stacking S50-01-12G-2S 1-port 24GbE Stacking S50-01-24G-1S The system supports any of the modules inserted in any combination of slots (although connecting all four ports of two 12G stacking modules is not supported, nor is connecting a 12G stack port in one switch to a 24G stack port in another switch). The ports are numbered 49 through 52, from left to right as you face the front of the chassis. So, for clarity in the use of the CLI in port assignment, if you are only using one XFP or CX4 module, insert it in the left-most expansion slot. NOTE: The 10G modules cannot be used for stacking. See Connecting Stack Ports (optional) on page 25. Installing the Switch | 17 | support.dell.com To install a module, follow the steps below: Step 1 Task If the system is on, save the running configuration, if desired (and different from the startup configuration) with the command write memory. Then power down the system by unplugging it from its power source. CAUTION: Hot-swapping (inserting or removing) a module can crash and lock up the system, requiring a power cycle. Use a #2 Phillips screwdriver to remove either a module faceplate or an existing module. Note that these slots, when used for 10G Ethernet ports, are assigned port numbers from left to right as you face the front of the system. So, for clarity in programming those ports, you might favor the left-most slot for the first 10G module that you install. 3 Grasp the module faceplate, and remove the module from its packaging, then slide it into the slot until the module faceplate is flush with the rear cover of the system. 4 Secure the captive screws on either side of the module. 5 The optical XFP 10-Gigabit module (Catalog # S50-01-10GE-2P) requires additional XFP transceiver inserts, which are not included in the module kit. See Installing XFPs on page 44 or the installation instructions that come with the transceiver. fn00144s50V 2 CAUTION: You can connect a CX4 cable to an XFP port through a CX4 XFP converter (catalog number GP- XFP-1CX4) in the slot. However, an XFP port does not support the use of the cx4-cable-length command, discussed next. CX4 module (catalog number S50-01-10GE-2C) ports do not require inserts. If you are installing a CX4 module, and you are connecting the ports with a cable substantially shorter or longer than 5 meters, use the cx4-cablelength command to set the signal strength. Use cx4-cable-length long for a longer cable, cx4-cable-length short for a shorter cable. For details when using FTOS, see the Interfaces chapter in the FTOS Command Reference. When using SFTOS, see the System Management Commands chapter in the SFTOS Command Reference for details. NOTE: Take care not to connect CX4 ports to 12G stack ports in the switch. The receptacles and cables are the same, but they are incompatible. CX4 ports are labeled as such; stack ports are not labeled. You can order several cable lengths of each type; they are not part of the module kit. For details, see Using CX4 Cables (CX4 Cable Matrix) in the S-Series tech tips on iSupport: ToolTipsSSeries.aspx Installing the System on a Tabletop The system can be positioned on a stable tabletop. Four rubber standoffs are provided for that purpose in the plastic bag in the switch shipping box. Keep the following in mind when using a tabletop: 18 | Installing the Switch • Ensure that your tabletop is stable and can handle the weight of the switch or a stack of switches, if that is the case, along with any added backup power supplies. • Position the table for proper ventilation and easy access to separate power outlets for each device. Installing the System in a Rack or Cabinet The system provides three rack-mounting methods: • Two-Post Rack Mounting • Four-Post Rack-mounting with Threaded Rails • Four-Post Rack-mounting with Cage Nuts Two-Post Rack Mounting The switch is shipped with the universal front-mounting brackets (rack ears) attached. Ensure that there is adequate clearance surrounding the rack to permit access and airflow. If you are installing two switches side-by-side, position the two chassis at least 5 inches (12.7 cm) apart to permit proper airflow. Position the chassis in the rack. Secure the chassis with two of the supplied screws through each bracket and onto the rack post. Figure 4-1. Two-post (Front-mounted) Rack-mounting fn00147as50V Four-Post Rack-mounting with Threaded Rails Ensure that there is adequate clearance surrounding the cabinet or rack to permit access and airflow. If you are installing two S-Series side-by-side, position the two units at least 5 inches (12.7 cm) apart to permit proper airflow. Follow the steps below to install a unit into a 4-post 19-inch equipment rack, using the attached front mounting brackets and the optional adjustable rear-mounting brackets. Installing the Switch | 19 | support.dell.com Step Task Align the three screw holes of the adjustable rear mounting bracket with the three holes in the unit, and secure the mounting bracket with three screws. 2 Insert the unit into the rack, and secure the chassis to the front post with two screws. Then secure it to the rear posts with two screws. fn00146s50V 1 fn00147s50V 20 | Installing the Switch Step 3 Task Set the adjustable rear mounting bracket to the length (one of three lengths) for your bracket. Secure the length with the four screws. Figure 4-2. Four-post Rack-mounting with Adjustable Rear-mounting Brackets fn00148s50V Four-Post Rack-mounting with Cage Nuts Ensure that there is adequate clearance surrounding the cabinet or rack to permit access and airflow. If you are installing two S-Series systems side-by-side, position them at least 5 inches (12.7 cm) apart. Follow the steps below to install the unit into a four-post rack mounting with cage nuts. Step 1 Task Attach the two rear brackets to the side panels. Align the three holes in the bracket with the three holes on the chassis, and secure the brackets to the chassis using the screws. Top View of Brackets Align brackets fn00147f_s50V 2 Align and secure the adjustable bracket onto the rear bracket. Installing the Switch | 21 | support.dell.com Step Task Insert the chassis into the rear of the rack. Position and secure the chassis with two screws into each front bracket flange and into the rack post. 4 Position the cage nuts over the holes on each bracket flange and each rack post. fn00147a_s50V(4post) 3 fn00147d_s50V 22 | Installing the Switch Step 5 Task Align the rack filler panel to the rear bracket and rack posts. Secure by inserting two screws into the hole in the filler panel through to the holes in the rack post. fn00147e_s50V Stacking You can add, remove, or swap units in an existing stack. The units in the stack can continue running as you add new units, but new units should be powered down during the connection. All units in a stack must run the same version of the operating system. If you attempt to attach a unit with a different version of the operating system to an existing stack, the CLI will display an error, and the unit will not be added until you install compatible software. The order in which the units come on-line or are added to or removed from the stack can affect how the stack identifies them, and how the units identify themselves, influencing unit numbers, management addresses, and other elements of the configuration file. How units are identified within the stack is determined by the selected identification algorithm. The default algorithm has the units self-identify as Unit 1 through Unit [last] based on the order in which they come on-line. So, when setting up a new stack, you should have no trouble forcing the identification of the management unit and unit IDs by methodically supplying power to the units in your preferred sequence. Similarly, when you add a brand new unit to the stack, the unit will be gracefully added as Unit [last] (the lowest unused number) with the current configuration. If you have a pre-configured unit to add to the stack, but you want to make sure that the configuration does not override the configuration of the stack, it is best to add the unit while it is powered down, in order to avoid stack management conflicts. Installing the Switch | 23 | support.dell.com Using SFTOS Stacking Commands If the switch is running SFTOS, the commands available to manage stacking are described in the Stacking chapters of the SFTOS Command Reference and the SFTOS Configuration Guide. You can execute clear config on the switch to start a clean configuration. Then pre-configure it, as recommended in Best Practices in the Stacking chapter of the SFTOS Configuration Guide. You can use the SFTOS CLI to make stack identification changes on the fly: • Renumber units: switch renumber • Assign a new management unit: movemanagement • Remove a unit from stack membership: no member You can also use commands such as switch priority and member that override the default unit identification algorithms. Use the show switch command to see the current assignment of the management unit. Use the show switch unit command to see the serial number of the designated unit. For details on and other stacking commands, see the Stacking chapter in the SFTOS Configuration Guide and the Stacking Commands chapter in the SFTOS Command Reference. Using FTOS Stacking Commands If the switch is running FTOS, the following commands are available to manage stacking: • Use the stack-unit unit priority 1-14 command to configure the ability of an S-Series switch to become the management unit of a stack. • Use the stack-unit unit provision {S25N|S25P|S25V|S50N|S50V} command to pre-configure a stacking ID of a switch that will join the stack. This is an optional command that is executed on the management unit. • Use the stack-unit unit renumber unit command to renumber a standalone S-Series or any stack member except the management unit. • Use the show system brief command to see the current assignment of the management unit. • Use the show system stack-unit unit command to see the serial number of the designated unit and other system details. • Use the show system stack-ports command to see the stacking topology and status. For details on using FTOS to remove a unit from a stack or use other stacking commands, see the Stacking Commands chapter in the FTOS Command Reference and the S-Series Stacking chapter in the FTOS Configuration Guide. 24 | Installing the Switch Connecting Stack Ports (optional) The switch contains two expansion slots in the rear, in either of which you can insert stacking modules for converting the switch into a virtual slot in a single virtual switch, called a stack, comprised of any SSeries model running the same software. The S50V and S50N include two optional choices in stacking modules — a single-port 24G module and a two-port 12G module. You cannot interconnect the two types. If you use single-port 24G modules, you can insert one in each expansion slot to accomplish the ring topology. You can connect the switches while they are powered down or up. You can use either a ring topology or cascade topology connection (see Figure 4-3). Use the special stacking cables to connect them. Dell Force10 recommends that you mount the switches before you make your stack port connections. Figure 4-3. Switch Stacking Topologies (showing dual-port modules) Ring Topology Switch 1 Switch 2 Switch 3 A B A B A B Cascade Topology Switch 1 Switch 2 Switch 3 A B A B A B While the diagram, above, shows A-B port connections, the ports are bi-directional, so you can connect A to A and/or B to B, as shown below in examples of two-switch (Figure 4-5) and three-switch (Figure 4-6) ring topologies. Figure 4-4 shows the use of 24G stacking ports in each of the two rear modules to create a ring. Of course, this topology does not allow the use of any rear modules for XFP ports. A cascade topology, removing the stack port modules in the B slots of switches 1 and 2, would free those slots for use by XFP modules. Installing the Switch | 25 | support.dell.com Figure 4-4. Stacking Topology Using 24G Single-port Modules Module A Switch 1 Switch 2 Switch 3 Module B A B A B A B Ring topology using two 24Gig modules per unit Connecting Two Switches Insert one end of the special stacking cable into a stack port, and insert the other end into a stack port of the adjacent switch. Optionally, insert a second cable into the other open stack port, as shown in Figure 4-5. The second cable provides both backup connectivity and increased data transfer between the units. Figure 4-5. Stack Ports of Two S50V Switches Connected in a Ring FG -48V -48V Current RTN Sharing STACK STACK FG -48V -48V Current RTN Sharing STACK Stack Port A Stack Port B fn00151s25V1 STACK NOTE: These diagrams and instructions use “Stack Port A” and “Stack Port B” for clarifying the connections, but the modules are not labeled. Connecting Three Switches Dell Force10 recommends the ring topology, as outlined above (Figure 4-3 on page 25), for stacking SSeries switches, providing redundant connectivity. Using the example of three switches in the stack (Figure 4-6), and starting with the switch at the bottom of the stack: • Insert one end of the first cable into Stack Port A. • Insert the other end of the cable into Stack Port A of the middle switch. • Insert the second cable into Stack Port B of the middle and top switches. 26 | Installing the Switch • Connect the remaining cable to the top and bottom switches by inserting one end of the cable into the open Stack Port B of the bottom switch and the other end of the cable into Stack Port A of the top switch. Figure 4-6. S50V Rear View Showing Ring Topology Stacking FG -48V -48V Current RTN Sharing STACK STACK FG -48V -48V Current RTN Sharing STACK STACK FG -48V -48V Current RTN Sharing Stack Port A STACK Stack Port B fn00152s50V1 STACK Supplying Power Supply power to the switches in a stack only after they are mounted and the stack ports are connected. There is no on/off switch, and the stack members partly determined the stack management unit from the order in which they come on-line (see below). The S50V and S50N switches have both AC (3-prong plug receptacle) and DC (-48V terminal-type) connections on the back of the unit (see Figure 2-2 on page 9 and Figure 3-1 on page 15). They can use either power source independently or in combination, with the DC source in a backup mode (except for the 470W DC power supply, as noted in the section Power on page 14). In other words, you have three options for providing power to the switch — AC only, DC only, or using both AC and DC sources. If you select the third choice — AC and DC — the switch will only use the DC source after the AC source fails. In addition, Dell Force10 provides, as an option, an external DC Redundant Power Supply Unit (PSU), which has an AC input and a cable for connecting the PSU to the DC terminal leads on the switch. To connect the switch to a DC power supply, refer to Chapter , Installing Backup Power, on page 29. For PoE use, see Connecting S50V Ethernet Ports with PoE on page 42. For the S50V and S50N, to use AC only, connect the supplied AC power cord first to the switch (receptacle on the right as you face the rear of the chassis) and then to the power source (see AC Power Requirements on page 48). Connect the plug to the AC receptacle at the right rear of the switch, making sure that the power cord is secure. S50N-DC As shown in the section Power on page 14 in the Site Preparation chapter, S50N-DC switches have two terminal blocks on the right side (instead of an AC receptacle) for two DC power supply inputs. The terminal block on the right, as you face the back of the chassis, is matched to the DC1 status LED on the Installing the Switch | 27 | support.dell.com front left of the switch (see Figure 2-2 on page 9); the left block is matched to the DC2 status LED. You must provide your own cables to connect to the power source. Cables must be sized for 11.5 A service at no more than -48VDC input (per NEC in the United States; internationally, follow local safety codes.). Before you make the cable connections, apply a coat of antioxidant paste to unplated metal contact surfaces. File unplated connectors, braided straps, and bus bars to a shiny finish. 1 2 3 4 5 6 28 | Make sure that the remote power source (the circuit breaker panel) is in the OFF position. Remove the safety cover from the DC terminal block. Connect the grounding cable to the FG terminal first, then connect the opposite end to the appropriate grounding point at your site to ensure an adequate chassis ground. Connect the -48 V and -48 V RTN (Return) cables to the switch terminals and then to the remote power sources, ideally on separate circuit breakers. Replace the safety covers on the DC terminal blocks. If you are connecting both terminal blocks, do not supply power until both terminal blocks are connected. You can supply power to either one or both. The S50N-DC does not set a precedence for either power source. Installing the Switch 5 Installing Backup Power This chapter covers the following topics: • Backup Power Components • The Power Connections on the Switch on page 30 • Installing the Backup DC Power Supply for the S50V on page 30 • Inserting Tandem S50V PSUs into a Rack on page 31 • Connecting the S50V DC-to-DC Cable on page 32 • Installing the Backup DC Power Supply for the S50N on page 34 • DC Components on page 34 • Installing the External Power Shelf (optional) on page 35 • Inserting an S50N PSU into the EPS on page 36 The S50V and S50N switches have both AC and DC power connections (S50N-DC has two DC terminal blocks, no AC). You can connect either one or both. When both are connected, the AC input is slightly preferred over the DC (about 60% / 40%). When you connect the Dell Force10 470W DC Power Supply Unit (PSU) to the Current Sharing terminal of the S50V, the AC and DC are in additive mode, totalling 940W. NOTE: Neither internal nor external S-Series power supplies are field serviceable. If an internal power supply fails, the switch must be replaced. WARNING: To prevent electrical shock, make sure the switch is grounded properly. If you do not ground your equipment correctly, excessive emissions can result. Use a qualified electrician to ensure that the power cables meet your local electrical requirements. See other relevant cautions in Information Symbols and Warnings on page 5. Backup Power Components The optional Redundant Power Supply Unit (PSU) for the S50V supplies 470W DC, supporting both the switch itself and the PoE feature. The PSU kit includes: • The AC/DC rectifier (catalog number S50-01-PSU-V) • DC-to-DC cable to connect the PSU to the switch • AC cable to connect the PSU to the AC power source • PSU mounting hardware: extended rack ears, twinning plate, screws, cage nuts, and four rubber feet that you can attach to the PSU if you want to set it on a table Installing Backup Power | 29 | support.dell.com The Power Connections on the Switch The S50V and S50N contain both AC and DC connections. An AC cable is supplied with the switch (see Supplying Power on page 27). You can connect one or both of the AC or DC inputs to power. If both connections are made and able to supply power, the switch will use them in load-sharing mode. The DC input to the switch uses industry-standard terminal leads on a terminal block. The S50V has four connections — ground (FG), -48 volt input, return (RTN), and Current Sharing, as shown in Figure 5-1: Figure 5-1. DC Terminals on the S50V The S50N has three DC connections — return (RTN), -48 volt input, field ground (FG) — from left to right. Figure 5-2. DC Terminals on the S50N The S50N-DC has two terminal blocks, each with the same three DC connections as the S50N. WARNING: A qualified electrician should make the DC connections. Installing the Backup DC Power Supply for the S50V The Redundant Power Supply Unit (PSU) for the S50V is a 470W AC/DC rectifier. It includes rackmounting hardware, an AC cable, and a cable to connect to the DC power leads on the S50V. The power supply is oversized to support the Power over Internet (PoE) feature, too large to install in the S50 External Power Shelf. Instead, to install the Redundant Power Supply in a rack, complete the steps below 30 | Installing Backup Power for a single unit. For a tandem installation, see Inserting Tandem S50V PSUs into a Rack on page 31. Step 1 Task Using a #2 Phillips screwdriver, attach the short sides of the rack ears to the front corners of the power supply with the supplied screws. Figure 5-3. Attaching Rack Ears to PSU 2 Insert the power supply into the rack and brace it temporarily in the rack so that the screw holes in the long sides of the rack ears are flush and align with the screw holes in the rack posts. 3 Secure the power supply on the left and right sides by tightening the supplied screws through the flanges to the side of the rack, as shown in Figure 5-4. (Cage nuts are also supplied for racks that have mounting holes without threads.) Figure 5-4. Mounting Single PSU in Rack Inserting Tandem S50V PSUs into a Rack To install two S50V PSUs (the 470W Redundant Power Supply) in tandem (side-by-side) in a rack, follow these steps: Step 1 Task Using a #2 phillips screwdriver, attach the supplied extended rack ears to the outside, front sides of the two PSUs. As shown in Figure 5-6, the long side of the rack ear is attached to the PSU, with the short side projecting at right angles away from the front corner of the PSU. Installing Backup Power | 31 | support.dell.com Step 2 Task Join the two units with the supplied twinning plate (the small, flat, I-beam-shaped metal adapter with four screw holes), using two screws on each side of the plate through the front inside corners of the two switches. Orient the adapter with the cross-bars of the I-beam horizontally, so that the fan and power LEDs in the left-hand PSU are not obscured. Figure 5-5. Twinning Plate Oriented over Two PSUs Power Fan 3 As shown on the left side of Figure 5-6, attach the rack ears to the rack with the supplied screws or cage nuts, depending on the style of your rack. Figure 5-6. Two PSUs Mounted Side-by-Side Connecting the S50V DC-to-DC Cable The PSU kit for the S50V includes two power cables — the cable that connects the PSU to the AC source and the DC-DC cable that connects the PSU to the terminal block on the back of the S50V. The DC-DC cable length is 1.5 meter (5 feet), with a keyed plug connector at one end that connects to the PSU, and, at the other end, individual wires that connect to the DC terminal leads in the rear of the S50V (Figure 5-7). 32 | Installing Backup Power Figure 5-7. DC-DC Cable for S50V PSU Follow the steps below to connect the S50V switch to the S50V external PSU. Step 1 Task With the switch unplugged from AC power, connect the individual leads of the DC-to-DC cable to the DC terminal lugs of the switch (Figure 5-8), with a #2 Phillips screwdriver. Connect the gray wire to FG, red to RTN, brown to -48V. If you connect the blue lead of the Dell Force10 PSU to Current Sharing, you put the PSU in load-sharing mode, which helps to enable more PoE ports. Alternatively, leaving the wire unconnected puts the PSU in backup mode. The downside of selecting load-sharing mode is that, if either the AC or DC fails, all PoE functionality is lost. Figure 5-8. DC Terminals of the S50V Connected to the PSU Cable CAUTION: Use only -48V DC. Using a higher voltage causes the DC source to take precedence over the internal AC PSU, causing the AC PSU to continually attempt to boot up. The symptom is a clicking noise. Installing Backup Power | 33 | support.dell.com Step 2 Task Insert the plastic plug of the DC-to-DC cable into the receptacle on the lower left side of the DC Power Module (DPM), which is the bottom box in Figure 5-9. Note that one of the three leads on the plug has a trapezoidal key , which goes in the receptacle that is toward the center of the PSU. The key is not strong enough to resist being inserted in the opposite receptacle, and it is difficult to see, so you must take care to insert it correctly. To help you orient it, note that the top side of the plug has a knurled pattern. Figure 5-9. DC-to-DC Connection S50V 11.5 -48V Current FG RTN -48V Sharing fn00153s50V DC-to-DC Cable DC Power Module 3 Tighten the captive screws on the sides of the connector cable by turning them clockwise. 4 Insert the supplied AC-to-AC cable into the AC receptacle of the DC power supply. Ideally, you should connect that cable to an AC source separate from the AC connection made directly to the S50V. Installing the Backup DC Power Supply for the S50N The Redundant Power Supply Unit (PSU) for the S50N is a 180W AC/DC rectifier. It is less powerful than the S50V PSU, because it does not need to support PoE. This 180W PSU is the same as used for the S50, so it can be housed in the External Power Shelf supplied for the S50. It does not have screw holes for rack ears, so it cannot be hung in a rack by itself. CAUTION: Use only the power cords supplied with the power supply. Do not supply power to the system until the power supply and modules have been installed. DC Components • The External Power Shelf (EPS) (Catalog# SA-01-EPS) • S50/S50N Power Supply Unit (PSU) (Catalog# SA-01-PSU), an external AC-to-DC rectifier • PSU mounting hardware: captive screws for attaching the unit to the External Power Shelf (EPS) 34 | Installing Backup Power • 5’(1.5m) DC-to-DC cable (two versions are included with the rectifier; see below.) • AC cable to the rectifier Installing the External Power Shelf (optional) Installing the PSU in a rack requires the External Power Shelf (EPS) (Catalog# SA-01-EPS), shown in Figure 5-10. It is a 2.5RU chassis that can house up to eight PSUs (for up to eight switches). Figure 5-10. Front and Back Views of External Power Shelf (EPS) (before inserting PSUs) Figure 5-11. EPS Mounting Bracket Shown here on its side, the bracket (rack ear) used for front and rear mounting of the EPS has two holes at one end of the rack flange that are closer together than those at the other end. When attached to the front corners of the EPS, the close-set holes are at the top on the left side of the EPS and at the bottom on the right side of the EPS. To connect to the typical rack, you insert screws through the outside holes on the left-side flange and through the inside holes on the right-side flange. Procedure: Attach the rack ears to the front or rear corners of the EPS, depending on where you are mounting it. 2 For front-mounting the EPC, slide the EPS into the rack from the front until the rack ears are flush with the rack posts. Then secure the EPS by tightening the supplied screws through its left and right rack ears. Figure 5-12 on page 36 shows the EPS mounted below an S50. 1 For rear-mounting the EPC, slide the EPS into the rack from the rear until the rack ears are flush, and Installing Backup Power | 35 | support.dell.com continue, as above. Figure 5-12 on page 36 shows the typically-used screw hole locations circled in red. Figure 5-12. 3 EPS Rear-Mounted (shown fully populated with PSUs) Insert a PSU into a bay of the PSE so that the captive screws align with the screw holes in the PSE, and then tighten the screws. Figure 5-13. EPS Front-Mounted (shown below an S50) fn00155s50 Inserting an S50N PSU into the EPS The Power Supply Unit (PSU) that supports both the S50 and S50N is an optional, external AC/DC rectifier that provides 180W DC at 48V. 36 | Installing Backup Power Figure 5-14. Power Supply Unit (PSU) for the S50 and S50N (shown upside down to show standoffs) To install the PSU into the External Power Shelf (EPS), follow these steps: Step Task 1. Grip the PSU by the attached handle (at the top of the PSU). 2 Slide the PSU into the bay until its front panel is flush with the shelf. 3 Secure it by tightening the screws on the left and right sides of the PSU. Connecting the DC-to-DC Cable for the S50N PSU The PSU kit for the S50 and S50N includes an AC cable and two DC-DC cables. One DC-DC cable is for the PSU-S50 connection (it has a plastic plug for connecting to the S50). The other DC-DC cable, for connecting the PSU to the S50N, has, at the S50N end, three individual wires with fork connectors that connect to the DC terminal block in the rear of the S50N (see Figure 5-15). In both cases (S50 and S50N), the DC-DC cable length is 1 meter (39 inches), with, at the end that connects to the PSU, a plastic plug containing two rows of three plastic connectors (see Figure 5-14). NOTE: You can also attach PSUs to one or both of the terminal blocks of an S50N-DC. The connections are the same as to the S50N. Installing Backup Power | 37 | support.dell.com Figure 5-15. DC-DC Cable for S50N Follow the steps below to connect the switch to the PSU: Step 1 Task With the switch unplugged from AC power, connect the DC-DC plug to the switch. Connect the individual leads of the DC-to-DC cable to the DC terminal lugs of the S50N switch (Figure 5-16) using a #2 Phillips screwdriver. Connect the gray wire to FG (field ground), red to RTN, brown to -48V: Figure 5-16. 38 | Installing Backup Power DC Terminals of the S50N Connected to the PSU Cable Step 2 Task Plug the other end of the DC-to-DC cable into the receptacle on the lower left side of the external PSU (Figure 5-9). Figure 5-17. DC-to-DC Connection S50N , 3.6A -48V RTN -48V FG fn00153s50N DC-to-DC Cable DC Power Module 3 Tighten the captive screws on the sides of the connector cable by turning them clockwise. 4 Insert your AC cable into the AC receptacle of the PSU. Ideally, you should connect that AC cable to an AC source separate from the AC connection made directly to the switch. Installing Backup Power | 39 40 | Installing Backup Power | support.dell.com 6 Installing Ports This chapter contains these major sections: • Accessing the Console Port on page 41 • Connecting S50V Ethernet Ports with PoE on page 42 • Installing Optics on page 43 Accessing the Console Port Table 6-1. Connect the RJ-45/DB-9 adapter that is shipped with the S50V system to the RJ45 cable. Console port pinout: Pin 1 = NC Pin 2 = NC Pin 3 = RXD Pin 4 = GND Pin 5 = GND Pin 6 = TXD Pin 7 = NC Pin 8 = NC Figure 6-1. Console Port of S50V Set your initial console terminal settings to match the default console settings on the switch: • 9600 baud rate 4 9 D arm • No parity 5 0 51 5 • 8 data bits • 1 stop bit • No flow control (console port only) After establishing a connection, you can modify the settings to match at each end of the connection. To access the console port, follow the procedure below. Step 1 Task Install the RJ-45 copper cable that is shipped with the S50V system into the console port. CAUTION: You must install a straight-through RJ-45 copper cable (a standard Ethernet cable) into the console port. This is different from many other implementations that require an Ethernet crossover cable (or rollover cable). If connecting to a terminal server and using a crossover cable, daisy chain another crossover cable to effectively get a straight-through cable connection. Many console terminal servers use octopus cables that are crossover cables. To accommodate the octopus cable, connect an additional crossover cable, as above, to effectively install a straight-through cable. 2 If necessary, connect the RJ-45/DB-9 adapter that is shipped with the S50V system to the end of the RJ-45 cable that will connect to your terminal. 3 Verify that your terminal default settings match the default settings, as listed above, on the console port: Installing Ports | 41 | support.dell.com Step 4 Task (continued) If you use the console port to download software to the switch, you should raise the console baud rate. If SFTOS is installed, establish a connection with the default settings to verify the connection. Then use the lineconfig command to access the Line Config mode, and use the serial baudrate command to raise the baud rate on the console port. Match the settings in your terminal access program. If FTOS is installed, to make other console port configuration changes, such as setting the console port timeout or setting up access security, use the line console command in the CONFIGURATION mode. Connecting S50V Ethernet Ports with PoE The copper ports (1 through 48) in the S50V are enabled by default to deliver power to connected powered devices that follow the IEEE 802.3af specification for Power over Ethernet (PoE). For delivering PoE, use the same Cat. 5 cables and RJ-45 connectors that you use for non-PoE connections. The PoE pinout is shown in Figure 6-2. Figure 6-2. RJ-45 PoE Pinout The internal AC 470 watt power supply will limit PoE power to 320 watts if the switch requires power for other uses, and the default PoE configuration limits PoE power to 288 watts. As described in Power over Ethernet (PoE) Support on page 15, you can raise that limit with an external power supply running in loadsharing mode and with certain FTOS and SFTOS commands. The PoE commands of FTOS and SFTOS are summarized here. NOTE: For details on commands that control PoE, see the PoE chapters of the Configuration Guide and Command Reference for your software. 42 | Installing Ports Table 6-2. PoE Commands FTOS SFTOS [no] power-budget stack-unit 0-7 321-790: inlinepower {disable | enable} unit-id: (Global Config (CONFIGURATION mode) Enable PoE power from a 470W mode) Enable or disable PoE for a specified switch in an SRedundant Power Supply (catalog # S50-01-PSU-V), if Series stack. attached to the designated stack member. inlinepower admin {off | auto}: (Interface Config mode) Enable or disable PoE on a particular port. [no] power inline {auto [max_milli-watts] | static [max_milli- inlinepower limit 1-20: watts]}: (INTERFACE mode) Enable power to be supplied to (Interface Config mode) Set a power limit on the port. a device connected to a port [no] power inline priority {critical | high | low}: (INTERFACE mode) Set the PoE priority of the port. inlinepower priority {critical | high | low}: (Interface Config mode) Set a PoE priority on the port. show power inline: (EXEC, EXEC privilege modes) Display inlinepower threshold 0-100 unit-id: the ports that are enabled with PoE and the amount of power (Global Config mode) Override the 80% default limit of the PoE power budget. that each is consuming show power supply: (EXEC, EXEC privilege modes) Display show inlinepower [unit/slot/port | all]: the power supply status. (User Exec, Privileged Exec modes) Display the power status for one or all ports. Installing Optics This section contains two subsections: • Installing SFPs on page 43 • Installing XFPs on page 44 The S50N and S50V each have four receptacles at the right end of their faceplates that accommodate 10/100/1000 SFP optical transceivers. On the back of the switches, there are two bays that accept either stacking modules or 10GbE modules (CX4 or XFP). A 10GbE module contains two ports. 10GbE modules should only be inserted or removed when the switch is powered down, as detailed in Inserting Optional Modules (10-Gigabit or Stacking) on page 17 in Chapter 4, Installing the Switch. SFP and XFP transceivers can be inserted or removed while the switch is running. CAUTION: Before connecting a transceiver to a source, check the receive power of the transceiver with an optical power meter. Generally, Dell Force10 specified optics are not to be subjected to receive power higher than that stipulated by the optic specification. If the optic is exposed to optical power in excess of the specification, there is a high likelihood that it will be damaged. Optical specifications for Dell Force10 branded devices are at the following URL: Dell Force10 offers various types of SFP and XFP transceivers. For details, see: Installing SFPs To install an SFP transceiver into an open optical port at the right front of the switch, use the steps below: Installing Ports | 43 | support.dell.com WARNING: Electrostatic discharge (ESD) damage can occur if components are mishandled. Always wear an ESD-preventive wrist or heel ground strap when handling the switch and its components. Step Task 1 Position the SFP so it is in the upright position. (The SFP has a key that prevents it from being inserted incorrectly.) 2 Insert the SFP into the port until it gently snaps into place. Figure 6-3. Front View of S50V with SFP fn00162s50V Installing XFPs To install an XFP into one of the two ports in the optional 10GbE optical module (see Inserting Optional Modules (10-Gigabit or Stacking) on page 17) on the back of the switch, follow the procedure below: WARNING: Electrostatic discharge (ESD) damage can occur if components are mishandled. Always wear an ESD-preventive wrist or heel ground strap when handling the switch and its components. WARNING: Do not look directly into any optical port. Failure to follow this warning could result in physical harm. For details, see Information Symbols and Warnings on page 5. Step Task 1 Position the XFP so it is in the upright position. (The XFP has a key that prevents it from being inserted incorrectly.) 2 Insert the XFP into the port until it gently snaps into place. Figure 6-4. Rear View of S50V with XFP fn00160s50V CAUTION: You can insert and connect XFP transceivers while the switch is operating. You can also disconnect and remove XFP transceivers while the switch is operating. However, inserting or removing the module is not supported; it can crash or lock up the switch, requiring a reboot. 44 | Installing Ports CAUTION: The CX4 module does not use transceivers. However, you can use a CX4 cable with an XFP port by inserting a CX4 XFP converter (catalog name GP- XFP-1CX4) into the slot. An XFP port does not support the use of the cx4-cable-length command. For details, see Inserting Optional Modules (10-Gigabit or Stacking) on page 17. For enabling ports with FTOS, see the FTOS Configuration Guide. With SFTOS, see the SFTOS Configuration Guide or the S50V and S50N Quick Reference. Installing Ports | 45 46 | Installing Ports | support.dell.com 7 Switch Specifications This chapter contains these sections: • Chassis Physical Design • Environmental Parameters on page 48 • Power Requirements on page 48 • Agency Compliance on page 49 NOTE: The specifications in this chapter, unless otherwise noted, pertain to the S50V (catalog # S50-01-GE48T-V) and S50N (catalog # S50-01-GE-48T-AC for AC-powered version of S50N; catalog # S50-01-GE-48TDC for S50N-DC). Chassis Physical Design Parameter Specifications Weight (weight with factory-installed components) 14.41 pounds (approx.) (6.54 kg) Height 1.73 inches (4.4 cm) Width 17.32 inches (44 cm) (19" rack-mountable) Depth 16.73 inches (42.5 cm) (standard 1 rack unit – 1RU) Rack clearance required Front: 5 inches (12.7 cm) Rear: 5 inches (12.7 cm) Switch Specifications | 47 | support.dell.com Environmental Parameters Parameter Specifications Temperature Operating: 32° to 122°F (-0° to 50°C) Non-operating (storage temperature): -40° to 158°F (-40° to 70°C) Maximum Thermal Output S50N: 531 BTU/Hour S50N-DC: 465 BTU/Hour S50V: 497 BTU/Hour Maximum altitude No performance degradation to 10,000 feet (3,048 meters) Relative humidity 10 to 85% non-condensing Shock Designed to meet MIL-STD-810 Vibration Telcordia GR-63-CORE ISO 7779 A-weighted sound pressure level S50N: 42.0 dBA at 73.4°F (23°C) S50V: 62.2 dBA at 73.4°F (23°C) Power Requirements AC Power Requirements Parameter Specifications Nominal input voltage 100 – 240 VAC, 50/60 Hz Maximum current draw 6.5 A @ 115 VAC 3.25 A @ 200/240 VAC Maximum power consumption S50N: 156W S50N-DC: 136 W S50V: 146W Maximum PoE power 320W for PoE using either AC or DC inputs 790W for PoE using load-sharing AC and DC inputs DC Power Requirements 48 | Parameter Specifications Nominal input voltage -48V to -54Vz Maximum current draw S50N-DC: 3.6 A at -48 VDC S50V: 11.5 A @ -48VDC Maximum system power consumption S50V: 470W (790W using current-sharing AC and DC inputs) S50N: 102W S50N-DC: 136W Switch Specifications NOTE: The S50N and S50V switches contain a lithium battery. The switch contains no user-serviceable parts. For details on recycling the switch or any of its components, see Product Recycling and Disposal on page 52. Agency Compliance The S50N and S50V are designed to comply with the following safety and agency requirements. USA Federal Communications Commission (FCC) Statement This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC rules. These limits are designated to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy. If it is not installed and used in accordance to the instructions, it may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in which case users will be required to take whatever measures necessary to correct the interference at their own expense. Properly shielded and grounded cables and connectors must be used in order to meet FCC emission limits. Dell Force10 is not responsible for any radio or television interference caused by using other than recommended cables and connectors or by unauthorized changes or modifications in the equipment. Unauthorized changes or modification. Canadian Department of Communication Statement European Union EMC Directive Conformance Statement This product is in conformity with the protection requirements of EU Council Directive 2004/108/EC on the approximation of the laws of the Member States relating to electromagnetic compatibility. Dell Force10 cannot accept responsibility for any failure to satisfy the protection requirements resulting from a non-recommended modification of this product, including the fitting of non-Dell Force10. WARNING: This is a Class A product. In a domestic environment, this device may cause radio interference, in which case, the user may be required to take adequate measures. European Community Contact Dell Force10, EMEA - Central Dahlienweg 19 66265 Heusweiler Germany Tel: +49 172 6802630 Email: EMEA Central Sales Switch Specifications | 49 | support.dell.com Japan: VCCI Compliance for Class A Equipment This is Class A product based on the standard of the Voluntary Control Council For Interference by Information Technology Equipment (VCCI). If this equipment is used in a domestic environment, radio disturbance may arise. When such trouble occurs, the user may be required to take corrective actions. WARNING: AC Power cords are for use with Dell Force10 equipment only. Do not use Dell Force10 AC power cords with any unauthorized hardware. Korea (MIC certification) Korea Certification 50 | Switch Specifications Korea Information Safety Standards and Compliance Agency Certifications • CUS UL (60950-1, 1st Edition) • CSA 60950-1-03, 1st Edition • EN 60950-1, 1st Edition • EN 60825-1, 1st Edition • EN 60825-1 Safety of Laser Products—Part 1: Equipment Classification Requirements and User’s Guide • EN 60825-2 Safety of Laser Products—Part 2: Safety of Optical Fibre Communication Systems • FDA Regulation 21CFR 1040.10 and 1040.11 • IEC60950-1 1st Ed including all National Deviations and Group Differences Electromagnetic Compatibility (EMC) Emissions • Australia/New Zealand: AS/NZS CISPR 22: 2006, Class A • Canada: ICES-003, Issue-4, Class A • Europe: EN55022 2006 (CISPR 22: 2006), Class A • Japan: VCCI V3/ 2007.04 Class A • USA: FCC CFR47 Part 15, Subpart B, Class A Immunity • EN 300 386 v1.3.3: 2005 EMC for Network Equipment • EN 55024 1998 + A1: 2001 + A2: 2003 • • • • EN 61000-3-2 Harmonic Current Emissions EN 61000-3-3 Voltage Fluctuations and Flicker EN 61000-4-2 ESD EN 61000-4-3 Radiated Immunity Switch Specifications | 51 | support.dell.com • • • EN 61000-4-4 EFT EN 61000-4-5 Surge EN 61000-4-6 Low Frequency Conducted Immunity Product Recycling and Disposal This switch must be recycled or discarded according to applicable local and national regulations. Dell Force10 encourages owners of information technology (IT) equipment to responsibly recycle their equipment when it is no longer needed. Dell Force10 offers a variety of product return programs and services in several countries to assist equipment owners in recycling their IT products. Waste Electrical and Electronic Equipment (WEEE) Directive for Recovery, Recycle and Reuse of IT and Telecommunications Products Dell Force10 switches are labeled in accordance with European Directive 2002/96/EC concerning waste electrical and electronic equipment (WEEE). The Directive determines the framework for the return and recycling of used appliances as applicable throughout the European Union. This label, as shown in Figure 7-1 on page 52 is applied to various products to indicate that the product is not to be thrown away, but rather reclaimed upon end of life per this Directive. Figure 7-1. The European WEEE symbol In accordance with the European WEEE Directive, electrical and electronic equipment (EEE) is to be collected separately and to be reused, recycled, or recovered at end of life. Users of EEE with the WEEE marking per Annex IV of the WEEE Directive, as shown above,. Dell Force10 products, which fall within the scope of the WEEE, are labeled with the crossed-out wheelie-bin symbol, as shown above, as required by WEEE. For information on Dell Force10 product recycling offerings, see the WEEE Recycling instructions on iSupport at:. For more information, contact the Dell Force10 Technical Assistance Center (TAC) (see Contacting the Technical Assistance Center on page 56). Notice to Recyclers To open the case: 1 52 | Remove the small phillips screws that connect the top to the body. There should be three evenly spaced across the rear and three evenly spaced along each side. Switch Specifications Slide the top backwards until its front flange slides free of the faceplate, then lift it off. To remove the lithium closed-cell clock battery (clearly visible towards the right rear of switch): 2 Insert a small, flat screw driver blade under the battery and in one of the slots of the plastic retainer underneath the battery. 2 Lever the battery up against the coin cell clip (the hold-down lead on top of the battery) far enough to provide room for the battery to be lifted above the edge of its retainer, as shown in this photograph. 1. For proper collection and treatment, contact your local Dell Force10 representative. Figure 7-2. The European WEEE symbol Switch Specifications | 53 | support.dell.com 54 For California: Perchlorate Material — Special handling may apply. See: The foregoing notice is provided in accordance with California Code of Regulations Title 22, Division 4.5 Chapter 33. Best Management Practices for Perchlorate Materials. | Switch Specifications 8 Technical Support This appendix contains these major sections: • The iSupport Website • Contacting the Technical Assistance Center on page 56 • Locating Serial Numbers on page 56 • Requesting a Hardware Replacement on page 57 The iSupport Website iSupport provides a range of documents and tools to assist you with effectively using Dell Force10 equipment and mitigating the impact of network outages. Through iSupport you can obtain technical information regarding Dell Force10 products, access to software upgrades and patches, and open and manage your Technical Assistance Center (TAC) cases. Dell Force10 iSupport provides integrated, secure access to these services. The iSupport website contains a publicly available interface that includes access to techtips, white papers, and user manuals. After you get an account and log in, the available documentation expands to other types, including bug lists, error message decoder, release notes. You can even track your own Dell Force10 inventory. Accessing iSupport Services The URL for iSupport is. To access iSupport services you must have a userid and password. If you do not have one, you can request one at the website: On the Dell Force10 iSupport page, click the Account Request link. 2 Fill out the User Account Request form, and click Send. You will receive your userid and password by E-mail. 3 To access iSupport services, click the LOGIN link, and enter your userid and password. See Contacting the Technical Assistance Center, below, for more. 1 Technical Support | 55 | support.dell.com Contacting the Technical Assistance Center How to Contact Dell Force10 TAC Information to Submit When Opening a Support Case Log in to iSupport at, and select the Service Request tab. • Your name, company name, phone number, and E-mail address • Preferred method of contact • Model number • Serial Number (see Locating Serial Numbers on page 56) • Software version number • Symptom description • Screen shots illustrating the symptom, including any error messages. These can include: Managing Your Case Log in to iSupport, and select the Service Request tab to view all open cases and RMAs. Downloading Software Updates Log in to iSupport, and select the Software Center tab. Technical Documentation Log in to iSupport, and select the Documents tab. This page can be accessed without logging in via the Documentation link on the iSupport page. Contact Information E-mail: support@force10networks.com Web: Telephone: US and Canada: 866.965.5800 International: 408.965.5800 Locating Serial Numbers You can use the show switch unit command in the CLI to access the serial number of the designated switch (unit = stack ID). The serial number of the chassis is located on a sticker on the back of the chassis in the middle. The serial number is below the bar code and has 11integers (numbers). 56 | Technical Support Figure 8-1. Serial Numbers on Back of Chassis Labels (Part #, Serial #, Mac Address, Bar Code, FRU #) 1234567 1234567 1234567 11.5 Current fn00163s50V -48V FG RTN -48V Sharing The serial numbers of the optional data modules (10G Ethernet and Stacking) are located on labels on their faces (some early-production modules have the PN on their baseboards). For serial numbers of the SFP optics, you can also access them through the CLI with either the show hardware or show runningconfig commands. The serial number label of the optional DC Backup Power Supply (see Backup Power Components on page 29) is located on the base of the chassis. Requesting a Hardware Replacement To request replacement hardware, follow these steps: Step Task 1 Determine the part number and serial number of the component. To list the numbers for all components installed in the chassis, use the show hardware command. 2 Request a Return Materials Authorization (RMA) number from TAC by opening a support case. Open a support case by: • Using the Create Service Request form on the iSupport page (see Contacting the Technical Assistance Center on page 56). • Contacting Dell Force10 directly by E-mail or by phone (see Contacting the Technical Assistance Center on page 56). Provide the following information when using E-mail or phone: • Part number, description, and serial number of the component. • Your name, organization name, telephone number, fax number, and e-mail address. • Shipping address for the replacement component, including a contact name, phone number, and e-mail address. • A description of the failure, including log messages. This generally includes: Technical Support | 57 58 | Technical Support | support.dell.com Index Numerics 10G module serial number 57 10-Gigabit module 15 10-Gigabit module, inserting 17 24G stack ports 25 A AC (110v/220v auto-detect) 10 AC Power Supply 6 AC/DC rectifier 30, 34 acoustic noise 48 AC-to-AC cable 34 AC-to-DC rectifier 34 adding units to an existing stack Agency Compliance 49 Alarm status LED 14 altitude, maximum 48 B back-pressure support 10 backup capability 14 Backup DC Power Module backup power 30 backup power (S50N) 34 backup power shelf 35 battery removal 53 battery, lithium 49 baud rate 41 brackets 10 23 10 C cabinet placement 13 cable, AC-to-AC 34 catalog name GP- XFP-1CX4 (for CX4 XFP) 45 catalog number GP- XFP-1CX4 (for CX4 XFP) 18 catalog number S50-01-10GE-2C (CX4 module) 18 catalog number S50-01-GE-48T-V (S50V) 17 catalog number, S50V 9, 17 catalog numbers 17 catalog numbers, module 17 Catalog# SA-01-EPS (S50 power shelf) 35 Catalog# SA-01-PSU (S50/S50N rectifier) 34 Catalog# SA-01-PSU-V (external rectifier for S25V and S50V) 29 Chassis Physical Design depth 47 height 47 width 47 commands cx4-cable-length 18 inlinepower threshold 16 member 24 movemanagement 24 no member 24 PoE 43 power-budget 16 show logging eventlog 57 show switch 24 show system brief 24 show system stack-ports 24 show system stack-unit 24 show tech 57 stack-unit priority 24 stack-unit provision 24 stack-unit renumber 24 switch priority 24 switch renumber 24 Connecting Stacking Ports 25 console port 15 console terminal settings 41 Current Sharing connection 15 current-sharing 15 CX4 module 45 CX4 ports 11 CX4 status LEDs 12 CX4 XFP converter 18, 45 cx4-cable-length command 18 D Danger 5, 6 DB-9 to RJ-45 10 DC (48V with terminal-type connectors) DC power module 27 DC Power Module (DPM) 34 DC Power Supply 6 DC-DC cable length 32, 37 DC-to-DC cable 29, 35 depth of chassis 47 disposal, switch 52 DPM (DC Power Module) 34 10 Index | 59 | support.dell.com E earth ground 14 electromagnetic noise 13 electrostatic discharge 16, 17 Emissions 51 Environmental Parameters 48 ESD 16, 17, 44 Ethernet crossover cable 41 Ethernet ports 15 European WEEE Directive 52 J jumbo frames L LED Displays 11 LEDs, port status 11 LEDs, stacking 11 LEDs, Status indicator 11 load-sharing 30 load-sharing mode 14, 15 Locating Serial Numbers 56 log messages 14 F fan replacement 14 fan speed 14 fans 10, 14 fans and ventilation 14 Flash memory 10 flow control 41 front panel 9 front panel, S50V 11 G ground connector grounding 14, 29 M MAC address 10 major alarm 14 Maximum altitude 48 Maximum Thermal Output 48 member command 24 modules, optional 17 mounting hardware 29 movemanagement command 24 15 H hardware, requesting replacement heat production 48 humidity, acceptable 13, 48 N no member command noise, acoustic 48 | Index 24 57 I ID, stack 12 IEEE 802.3af (PoE standard) 10 Immunity 51 inlinepower admin command 43 inlinepower command 43 inlinepower limit command 43 inlinepower priority command 43 inlinepower threshold command 16, 43 Installation Cabinet 19 Power shelf 35 Rack 19 Rack or Cabinet 19 Tabletop 18 iSupport 55 60 10 O octopus cables 41 optical port warning 44 P parity 41 pinouts, console port 41 PoE 10 PoE (Power over Ethernet) 10, 15, 16, 42 PoE (Power over Ethernet) commands PoE power budget 16 Port LED 11 port status indicator LEDs 11 ports 11 ports, shared 15 Power 14 power AC requirements 48 consumption 48 43 redundant DC requirements 48 Power components 29, 34 power cord 10, 15 power inline command 43 power inline priority command 43 Power over Ethernet (PoE) 10, 42 power receptacle 15 power shelf 35 power source 10 power supply 10 power supply LED 12 Power Supply module serial number power supply, tandem installation 31 power-budget command 16, 43 57 R rack clearance 47 Rack Installation 19 Rack Mounting 14 Four-post with threaded rails 19 grounding 14 Rear 21 Two-Post 19 RAM 10 rectifier 30, 34 recycling, switch 52 Redundant Power Supply Unit (PSU) removing a unit from a stack 23, 24 removing battery 53 requesting replacement hardware 57 RJ-45 installation 41 30, 31, 34 S S50-01-GE-48T-AC (S50N catalog number) 17 S50-01-GE-48T-DC (S50N-DC catalog number) 17 S50-01-GE-48T-V (S50V catalog number) 17 S50N (Cat# S50-01-GE-48T-AC) 9 S50N-DC (Cat# S50-01-GE-48T-DC) 9 S50V (Cat# S50-01-GE-48V) 9 S50V front view 9, 15 S50V PSU 30, 31, 34 S50V rear view 15 SA-01-EPS (catalog number for power shelf) 34, 35 SA-01-PSU (catalog number for rectifier) 34 Safety Standards 51 screws for rack installation 10 serial number, 10G Ethernet and Stacking modules 57 serial number, Backup Power Supply module serial number, SFP optics 57 serial number, switch 56 Serial Numbers, Locating 56 SFP installation 43 SFP Port LED 11 SFP ports 15 SFPs, Installing 44 shock and vibration 48 show commands 11 show inlinepower command 43 show logging command 14 show logging eventlog command 57 show power inline command 43 show power supply command 43 show switch command 24 show switch unit command 56 show system brief command 24 show system stack-ports command 24 show system stack-unit command 24 show tech command 57 SNMP traps 11 sound level 48 sound levels 48 Specifications Agency Compliance 49 chassis 47 environmental 13, 48 stack ID 12 stack port 15 Stack Ports diagram 26 stack ports, 24G 25 Stack, Swapping Units 23 stack, swapping units 23 Stacking cables 10 stacking connections 26 stacking indicator LED 15 Stacking LEDs 11 stacking limitations 25 stacking module, Inserting 17 stacking ports 11 Stacking Ports, Connecting 25 stacking S-Series switches 25 57 Index | 61 | support.dell.com stack-unit priority command 24 stack-unit provision command 24 stack-unit renumber command 24 Status indicator LEDs 11 status panel LEDs 9, 15 storage guidelines 16 Storing Components 16 straight-through cable 41 support contacts 55 Swapping Units 23 Swapping Units in a Stack 23 switch ID 12 switch priority command 24 switch recycling 52 switch renumber command 24 System Logs chapters 14 System Status 11 T Tabletop Installation 18 temperature acceptable ambient range 48 fans and ventilation 14 operating 48 relative humidity 16 storage 16, 48 warning message 14 terminal server 41 terminal settings, console 41 Thermal Output, Maximum 48 Tools Required 16 topology cascade 25 ring 25 V ventilation voltage 48 14 W Warning 6 AC Power Supply DC Power Supply WEEE 52, 53 Weight 47 width of chassis 47 62 | Index 6 6 X XFP Installation 44 XFP LINK/ACT 15 XFP Port LED 11 XFP ports 11 Printed in the U.S.A. | support.dell.com
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http://manualzz.com/doc/1627211/dell-s50v-specifications
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Set container and it’s important functions in C++ STL
Introduction
Set is an associative container present in C++ STL (Standard Template Library) that stores unique objects as keys. Set does not consider duplicate values. In the set, container key is equal to the value. Like any other associative containers in STL, a lookup for any element is done on the basis of keys.
To use set in C++ program ; include <set> header file.
Based upon the order in which keys are stored in a set container, they can be categorized into ordered and unordered sets.
1. Ordered set/Set
In an ordered set, unique keys are stored in an ordered manner, usually, they are stored in ascending order. The average time complexity for operations like insert and delete is logarithmic.
Declaration syntax : set <object_datatype > set_name;
ex: set <int> s; This statement will create an set container named s , that will store unique key of integer type in non-decreasing order.
Storing elements in the set in descending order
Use functional object class, greater<int> for changing the default order in which keys are stored in the set container.
#includes<bits/stdc++.h> using namespace std; int main() { set<int,greater<int>> s; s.insert(-9); s.insert(9); s.insert(19); s.insert(99); s.insert(-99); for(auto x: s) cout<<x<<' '; return 0; }
output:
99 19 9 -9 -99
2. Unordered set
In an unordered set, unique keys are stored in random order, i.e., Stored keys do not follow any particular order. Unordered set operations are generally faster than ordered set operations. The average time complexity for general operations like insertion and deletion is constant.
Declaration syntax : unordered_set <object_datatype > set_name;
frequently used functions in set :
begin(): it returns an iterator pointing to the first element of the set.
end(): it returns an iterator pointing to the hypothetical element post the last element of the set. Note: It is good practice to avoid accessing the memory location pointed by the end() function.
insert(): this function is used to store elements in the set container.
count(x) : this function returns count of element x, in the set. Since the set stores only unique elements, so the count of every element stored in the set is 1. The return type of this function is boolean, i.e., 0 or 1 in the set. If key x is not present in the set, then this it returns 0, otherwise 1.
find(x): this function returns an iterator pointing to the key x, if it is present in the set otherwise it returns the end() iterator.
functions for deleting elements in C++ set container
erase(): this function is used to delete a key or a range of stored keys. It can be used in 3 ways based on its input parameter:
- When a value, x is inserted as a parameter like erase(x), then key x is deleted from the set if it would have been present in the set.
- When an iterator, itr is passed as a parameter like erase(itr), then the key pointed by the iterator is deleted.
- A certain range of iterators can also be passed into erase() function to be deleted like erase(it, s.end()). This will delete all the keys stored at the memory location pointed by the leftmost iterator up to one position less than the rightmost iterator. NOTE: The right side iterator is excluded i.e., [left_iterator, right_iterator)
size(): it returns the size or no of keys stored in the set.
#include<bits/std++.h> using namespace std; int main() { set<int>s; s.insert(10); s.insert(20); s.insert(50); s.insert(100); s.insert(2); s.insert(-5); s.insert(10); cout<<"elements in set : "; for(auto x:s) { cout<<x<<' '; } cout<<"\nelements in set : "; if(s.count(10)) cout<<"10 is present in set\n"; else cout<<"10 is not present in set\n"; auto it=s.find(10); cout<<*it<<"\n"; cout<<"size of set is : "<<s.size()<<"\n"; s.erase(10); cout<<"elements in set after deleting 10 from it\n"; for(auto it=s.begin(); it!=s.end(); ++it) cout<<*it<<' '; it=s.find(-5); s.erase(it); cout<<"elements in set after deleting -5 from it\n"; for(auto it=s.begin(); it!=s.end(); ++it) cout<<*it<<' '; it=s.find(50); s.erase(it, s.end()); cout<<"elements in set after deleting -5 from it\n"; for(auto it=s.begin(); it!=s.end(); ++it) cout<<*it<<' '; return 0; }
Output :
elements in set : -5 2 10 20 50 100
elements in set : 10 is present in set
10
size of set is : 6
elements in set after deleting 10 from it
-5 2 20 50 100 elements in set after deleting -5 from it
2 20 50 100 elements in set after deleting -5 from it
2 20
lower_bound(x):
- This function returns an iterator to the first occurrence of the key, x if it is present in the set.
- If x is not present in the set, then it returns an iterator to the element just greater than x.
- If x is greater than the last element present in the set then it returns the hypothetical iterator s.end().
upper_bound(x):
- This function returns an iterator to a key just greater than x whether x is present in the set or not.
- It behaves the same as lower_bound when x is greater than the last element.
#include<bits/stdc++.h> using namespace std; int main() { set<int>s={0,1,3,-3,-6,10, 98, 786, 0, 1, 2, 3, 4}; cout<<"Elements stored in set : "; for(auto x:s) cout<<x<<' '; cout<<"\n"; set<int>::iterator it=s.lower_bound(0); cout<<*it<<"\n"; it=s.lower_bound(6); cout<<*it<<"\n"; it=s.lower_bound(1000); if(it==s.end()) cout<<"yes"<<"\n"; it=s.upper_bound(0); cout<<*it<<"\n"; it=s.upper_bound(6); cout<<*it<<"\n"; it=s.upper_bound(1000); if(it==s.end()) cout<<"yes"<<"\n"; return 0; }
output :
Elements stored in set : -6 -3 0 1 2 3 4 10 98 786
0
10
yes
1
10
yes
Based on the uniqueness of elements stored in the set, there is one more variation of the set, Multiset. This article is about MULTISET.
If this article added any value to your algorithmic knowledge then please share your valuable feedback in the comment section. Thank you!
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https://www.codespeedy.com/set-container-and-its-important-functions-in-c-stl/
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My youngest daughter asked me this morning whether you can find the number 2013 in the digits of pi. I said it must be possible, then wrote the following Python code to find where 2013 first appears.
from mpmath import mp mp.dps = 100000 digits = str(mp.pi)[2:] digits.find('2013')
I use the multi-precision math package
mpmpath to get pi to 100,000 significant figures. I save this as a string and cut off the “3.” at the beginning to have just the string of digits after the decimal point.
The code returns 6275, so “2013” appears in the 6275th position in the string of digits. However, we usually count decimal places starting from 1 but count positions in a string starting from 0, so 2013 starts in the 6276th decimal place of pi.
So π = 3.14159…2013… where the first “…” represents 6,270 digits not shown.
* * *
Now we jump off into deeper mathematical water.
For some purposes, the digits of pi are random. The digits are obviously not random — there are algorithms for calculating them — and yet they behave randomly, and random is as random does.
If the digits of pi were random, then we could almost certainly find any sequence we want if we look long enough. Can we find any finite sequence of digits in the decimal expansion of pi? I would assume so, but I don’t know whether that has been proven.
You might expect that not only can you find 2013 in pi, but that if you split the digits of pi into blocks of 4, then 2013 and every other particular block would occur with the same frequency in the limit. That is, one would expect that the expansion of pi is uniform in base 10,000.
More generally, you might conjecture that pi is a normal number, i.e. that the digits of pi are uniformly distributed in every base. This has not been proven. In fact, no one has proved that any particular number is normal [reference]. However, we do know that almost all numbers are normal. That is, the set of non-normal numbers has Lebesgue measure zero.
22 thoughts on “Finding 2013 in pi”
In particular, it seems like we can claim to be able to find periodic sequences of arbitrary length in the expansion of an irrational number. Which seems true, but strange.
@Patrick Honner, do you think that’s is strange? I guess you never heard of The Book:
The Smartest Man in Babylon
(note: official abstrusegoose is currently in downtime)
Or, in tau, the proper circle constant, “2013” starts at digit 3480 (counting from 0, like a real programmer, 3479.)
@Patrick Honner, Not strange, I guess you never heard of The Book .
As you say, if pi truly does continue forever without repeating and is a truly random series of numbers, we would expect to find any finite series of numbers within the digits of pi. Let’s call the number represented by that series of digits x.
There must be no upper limit to the number of digits in x; the only stipulation is that it is finite.
Let f(n) be the integer truncation of pi times 10 to the n. So f(3) is 3,141 and f(5) is 314,159.
For any n, f(n) must appear somewhere in pi. Given the above, this can be trivially proven through induction.
Does this imply that the decimal digits of pi must include pi?
That seems wrong, because it violates the stipulation that the length of x’s digit string must be finite. but if it’s wrong, that means there exists some n where f(n) is not included in the decimal digits of pi.
There’s probably some property of infinite sets that I’m forgetting from college that makes this question silly, and I’ve never been much for higher maths. But I’m having a bit of trouble turning it over in my head.
Hello, John.
Are you aware of this definition?
In particular “it is widely believed that the numbers √2, π, and e are normal, but a proof remains elusive.”
Awesome. I hear that every knowledge that can be written are contained in pi. Is there any proof of this? I mean, can we proof that any character combination if converted to number are exist on pi?
@Nathan: Such is the nature of infinity.
The fact that almost all numbers are normal helps drive home the fact that the set of numbers humans actually use (or ever will use) has measure zero.
Nitpicking, but wouldn’t it be the 6274th decimal place of pi? You went 1 in the wrong direction. For example, look at the first “5” in pi:
pi = 3.141592…
String position(0-indexed): 5th
Decimal place: 4th
so 6275th string position should be the 6274th decimal, not 6276th?
Or did I misunderstand something?
Funny: I just wrote a function that looks for the first integer that doesn’t appear in digits. Seems to be 10000.
Last I looked into it IIRC, if every particle in the universe was used to encode a digit of pi, there would be a 50% chance of finding an arbitrary 300 digit number therein. Bits instead of digits perhaps, but the point remains: finding particular data of any meaningful length in pi is theoretically assured but practically improbable.
@Mufti: In an infinite sequence of random digits, there will eventually come a sequence of consecutive digits that encodes (say) the complete works of Mark Twain, or Mahler’s 9th symphony, or any other work, using any prespecified encoding.
Using the definition of “normal number” at the link John provided — i.e. a number where the limiting frequency of any sequence of k digits is 1/b^k in base b — this will also be true of any normal number. If the complete works of Mark Twain requires k digits to encode, then once in every b^k subsequences of length k (on average) you will get the complete works of Mark Twain.
So, if pi is normal, then the answer is yes. I’m not clever enough to know whether, if pi is not normal, the answer might still be yes.
That pi is normal only implies that pi contains all *finite* sets of information in it. Pi probably does not contain, for instance, all the digits of sqrt2 or e consecutively. And it can only contain countably many finite sets of information.
About normal numbers, this has to relate to Kolmogorov complexity in some way, no?
Maybe PI is a normal number, but I wonder if it would no longer be true when looking at at a higher statistical moments of the distribution (but maybe I’m misunderstanding the concept of “density” used in the definition of normal number).
It would seem paradoxal that a number with a low Kolmogorov complexity (such as PI) appears as random as a number with a high Kolmogorov complexity (a true random coin flip).
There seems to be some incorrect information floating around in the post and comments. There are many specific numbers known to be normal (in base 10), Champerknowne’s number is a classic example. However, all of the numbers known to be normal are defined by way of their expansion, not through geometry or algebra.
For a number to be normal, it is not enough for every finite string to appear in its expansion, it must appear with the correct frequency! It is quite possible (in the logical sense) that every finite string of digits appears in the expansion of pi, but that pi is not normal. Nobody considers that a realistic possibility, but we are still unable to rule it out. In fact, it is still possible that from some point on the only digits that appear in pi are 0 and 3, say. IIRC, in Carl Sagan’s book Contact, some apparent non-normality of pi is discovered and this has implications for the plot.
There are many numbers known to be irrational but whose expansions are not normal and do not contain every finite string. For example, let a_i be 1 if there is a multiple of sqrt{3} between i and i+1, and let a_i be 0 otherwise. Then the number 0.a_1a_2a_3… is irrational (since it is not repeating and not finite), but you will never see two consecutive 0’s, nor three consecutive 1’s.
Here are some data points regarding the connection between normality and Kolmogorov complexity. The Kolmogorov complexity of x is – more or less – the length of the shortest program that takes input k and returns the k-th binary digit of x). pi is believed to be normal to every base, while it has low Kolmogorov complexity. The 0.a_1a_2… number in my earlier comment is not normal base-10 (but probably is to other bases), and also has low Kolmogorov complexity. Champernowne’s constant is definitely normal base-10, but likely not to other bases, and has low Kolmogorov complexity. In “Absolutely Abnormal Numbers”, Greg Martin gives a low Kolmogorov complexity number that is not normal to any base. A random sequence of 0’s and 1’s, with 0 twice as likely as 1, considered as the binary expansion of x, will have high Kolmogorov complexity will not be normal.
It does “feel” like there should be a connection, but I don’t see what form it could take.
100,000 was a pretty good guess for the precision, because the last 4 digit number that occurs in the fractional part of the decimal expansion of π is 6716, starting at 99,846.
Low level contribution: /mpmpath/mpmath/, link broken.
@Kevin
Last time I asked, was told that normal numbers and Kolmogorov complexity are not necessarily related, and basically are independent definitions of randomness. Certainly Pi is a good candidate for and example of it (if only we could prove it’s normal)
Did you include that bit about “random” and “normal” in the explanation to your daughter? If you kept her attention with that…good for her!
Can you check when will be the second, the third,.. of the occurrence of “2013”?
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* David S. Miller <20050127163146.33b01e95.davem@xxxxxxxxxxxxx> 2005-01-27 16:31
> The basic idea is that we stop trying to build TSO frames
> in the actual transmit queue. Instead, TSO packets are
> built impromptu when we actually output packets on the
> transmit queue.
Sound great.
> static inline int tcp_skb_data_all_paged(struct sk_buff *skb)
> {
> return (skb->len == skb->data_len);
> }
You could also define this as (skb_headlen(skb) == 0)
> The logic is simple because if TSO is being done we know
> that all of the SKB data is paged (since SG+CSUM is a
> requirement for TSO). The one case where that
> invariant might fail is due to a routing change (previous
> device cannot do SG+CSUM, new device has full TSO capability)
> and that is handled via the tcp_skb_data_all_paged() checks.
I assume the case when reroute changes oif to a device no
longer capable of SG+CSUM stays the same and the skb remains
paged until dev_queue_xmit?
> My thinking is that whatever added expensive this new scheme
> has, is offset by the simplifications the rest of the TCP
> stack will have since it will no longer need to know anything
> about multiple MSS values and packet counts.
I think the overhead is really worth the complexity that can
be removed with these changes.
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http://oss.sgi.com/archives/netdev/2005-01/msg01282.html
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Apache OpenOffice (AOO) Bugzilla – Issue 64689
Bubble chart
Last modified: 2013-02-24 21:20:59 UTC
cf : sample from Excel
Created attachment 35964 [details]
5.d-Bubble_charts.xls
accepted, set keywords, target and prio
Tony, could you also add a scr'eenshot of the bubble chart foc those not having
Excel ? Thanks !
Created attachment 36010 [details]
png sample
Hi Ingrid, this issue is UNCONFIRMED ?
Sorry, now it's accepted, as it should be :-)
*** Issue 71714 has been marked as a duplicate of this issue. ***
*** Issue 71692 has been marked as a duplicate of this issue. ***
This is the single reason I still have to resort to M$ Excel <sigh>
This has been outstanding for over a year, and is much more important to real
users than many of the eye candy changes to chart. This is forcing my users,
and many others, to Excel. Maybe it's time for a priority upgrade.
I do agree totally!
And I wonder why my 2 votes for this issue constitute 50% of all votes for this
issue :-(
It really is much more important than shown by the few votes.
Gisbert
Any news on this ?
more example of bubble charts
I use OpenOffice - among other things - to teach and do research in statistics,
and try to spread its use whenever possible. In this field, the absence of
bubble charts is a significant and annoying problem.
The continuing lack of bubble charts is one of those incomprehensible gaps that
sometimes go on unnoticed for years.
When I heard a revamping was in order for the charting module in 2.3, I wholly
believed bubble charting would be included. And I must agree that many of the
implemented improvements, while appreciable, were far less indispensable than a
good, flexible bubble chart option.
Almost everyday I have to answer - with difficulty and embarassment - some
students that ask about this problem.
Maybe it could be solved with an extension?
Or, as someone else suggested, it is simply time to give it a 2.4 target
milestone.....
change target to 3.x
28 votes ... I guess we'll never see this feature ...
the lack of this feature is the only reason why i need to keep Excel
installed.....
How can we make something happen? A petition? A hunger strike? I am positively
desperate about this...... I have the depressing perspective of another course
year on basic data management and analysis with OO calc WITHOUT bubble
charting.... please no!
Voted.
reset to new
@weiz, please implement the bubble chart.
For saving use the string 'bubble' for the attribute chart:class as defined in
ODF1.2.
You can take the scatter chart as example ( e.g. XML_SCATTER in xmloff ).
x and y values need to be saved within domain elements.
@weiz, a good start might be the chart type tab page. Introduce a new entry
there that represents the bubble chart and you will have something to test right
from the beginning on.
Look at class ChartTypeTabPage how the list m_aMainTypeList is filled.
Each main type is represented by a ChartTypeDialogController. Create a new class
BubbleChartDialogController. Use XYChartDialogController as example.
Created attachment 60455 [details]
patch_090224
@iha: The attached zip file contains the patch and new files for bubble chart.
Please let me know your suggestions. thanks.
This is absolutely good news!!!! I am starting my OpenOffice basic statistics
course just next monday.... what a coincidence.
If the patch works I will be able to use in the forthcoming weeks.
I will post any emerging problem here in the near future.
Thanks
I beg your pardon....
I am a quite low-tech user... how do I install the patch???
I thought some instructions would be included... or it had the form of an
extension.... or an exe. But how do I make use of a .patch file?
Sorry for my deep incompetence. Any hint appreciated!
@scagni, this kind of patch is nothing that can be installed to the product but
it is something to modify the underlying code. So it is necessary to apply the
changes to the OpenOffice.org code and then compile it.
All, please be careful when picking single patches from within the middle of the
developing phase. If you use them there is a general risk that you create files
that cannot be parsed by the final version! In addition there were no people
from the Quality Assurance involved so far.
@weiz, thanks for the patch! I will start to a look at it soon. Currently I am
in the middle of correcting and hopefully finalizing another patch/modification
that broke quite a lot in the fist attempts.
Thanks for the info. I will wait for a compiled version to be available then.
I hope this comes soon of course, but it will be welcome anyway whether after a
long or short time.
Sorry for the misunderstanding.
the known problems in the patch_090224:
* the save and load feature has not been completed.
* If the bubble chart has only one series, then click "Insert series" item in
the "Data Table" dialog, a new series include the "X-Values" "Y-Values" and
"Size-Values" will be inserted, it caused by "lcl_getSharedSequences" in
"DataBrowserModel.cxx", the comment in the function "if we have only one series,
we don't want any shared sequences".
* the patch only support 2D bubble chart.
I am very happy things are moving briskly on this:
regarding the problems reported, I would be in favour of implementing a working
version as soon as possible, leaving optional enhancements for later upgrades.
This holds for example for the present lack of 3D functionality: AFAIK a good 2D
bubble chart is used - and is appropriate - 95% of the times. Start with it
then: 3D bubble objects can easily follow later on
Thanks anyway for all the effort!
@weiz, I'll take over for implementation of save and load.
Save and load is implemented now.
Searching for further problems.
Set Daniel to CC for xls-im&-export.
The new role is "values-size".
The new service name is "com.sun.star.chart2.BubbleChartType".
import from XLS, XLSX; export to XLS done
test files: -> Chart Types ->
Scatter/bubble charts -> BIFF8, XML2003, XML2007
Thanks Daniel! :-)
Now its also possible to set color etc. for a single bubble point.
The bubble sizes for small values (<1) were wrong as the maximum was calculated
wrongly (>=1). This is corrected now.
Created attachment 61314 [details]
example with small bubble sizes < 1
Also corrected the scaling of the bubble sizes. They now do scale with the
diagram size. The maximum bubble size is now 25% of the diagram size (min of
width and height).
Found and fixed further problems with the automatic detection of number formats
to be used for the y-axis, the data table and the data label. I'll attach a file
to illustrate.
First the case where data comes from a spreadsheet. If no number format is set
explicitly at the y axis the number format used for the labels at the y axis
should be that of the value sequence representing the y values (not the size
values). If no number format is set explicitly for the data series (or point)
the number format used for the data point labels should be that from the size
sequence.
After copying such a chart from calc to impress the number format usage should
be as follows: Within the data table the x values should be displayed with the
number format set at the x-axis. The y-values should be displayed with the
number format set at the y axis and the size values should be displayed with the
number format set for the data labels at the series. During copy past the former
auto-detected number formats have to be set explicitely to the axis and data
series. This is aquivalent to how it works for xy charts within OOo 3.1.
Created attachment 61358 [details]
example for automatic number format detection
I updated several specifications:
-
A new entry 'Bubble' is inserted after 'XY (Scatter)' in the list of chart types.
-
For bubble charts a new entry 'Bubble Sizes' is offered per data series in the
'Data ranges' list.
-
For bubble charts the options 'Leave gap' and 'Assume zero' are available.
-
For bubble charts and scatter chart the option 'Show value as percentage is
disabled'. For bubble charts the same placement options are available as for
scatter charts.
Feedback from i-team was positive.
Created issue 101637 to update the documentation and issue 101635 to update the
automatic tests.
Finally added some spacing between data labels and bubbles.
Fixed in CWS bubblechart. Will resync to dev300m50 if that becomes available.
48 votes currently
The service description for the new type in the com::sun::star::chart-API was
also missing ->added.
Further options were not added to the bubble chart so far as they are not
defined with ODF yet, so it is not possible to save them with the document
currently. Those additional options can be added later after the file format is
extended.
I have written a feature request for example for the option to use the
size-values as diameter instead of area: issue 102779.
Please write additional issues if you want more options. Thanks for your input
and feedback.
50 votes.
->Thomas, please verify in CWS bubblechart.
Created attachment 63228 [details]
Testcasespecification Bubblechart
Long time waiting for and now -> verified in cws bubblechart
Just a _minor_ flaw I would like to mention:
In the schematic preview thumbnails of the bubble chart in the Chart Wizard
(seen here) are no
axes displayed, although there are axes.
E.g. the preview thumbnails of the pie charts have also no axes as there are
none, but column, bar, area, etc. does have axes in the picture...
(BTW: In case of Line and XY its also inconsistent as the axes are only
displayed in the left (first) preview, but not in the second previews on the right.)
@famo, the bubble icons were created consistently with the line and scatter
chart icons. If you think that it is worth the effort to change them all, please
write an issue to sts, as she designs the icons. Maybe such a change can be done
together with an overall redesign, as it sometimes happens. Thanks for your
input anyhow!.
Seen ok in current master -> closed
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Variables
A statement such as x = 5; seems obvious enough. As you would guess, we are assigning the value of 5 to x. But what exactly is x? x is a variable.
x = 5; defined, a piece of that memory is set aside for that variable.
In this section, we are only going to consider integer variables. An integer is a whole number, such as 1, 2, 3, -1, -12, or 16. An integer variable is a variable that holds an integer value.
In order to define a variable, we generally use a declaration statement. Here’s an example of defining variable x as an integer variable (one that can hold integer values):.
One of the most common operations done with variables is assignment. To do this, we use the assignment operator, more commonly known as the = symbol. For example:
When the CPU executes this statement, it translates this to “put the value of 5 in memory location 140″.
Later in our program, we could print that value to the screen using std::cout:
l-values and r-values
In C++, variables are a type of l-value (pronounced ell-values). An l-value is a value that has an address (in memory). Since all variables have addresses, all variables are l-values. The name l-value came about because l-values its value can not be reassigned. When an l-value has a value assigned to it, the current value at that memory address is overwritten.
5 = 6;
The opposite of l-values are r-values (pronounced arr-values). An r-value refers to any value that can be assigned to an l-value. r-values are always evaluated to produce a single value. Examples of r-values are single numbers (such as 5, which evaluates to 5), variables (such as x, which evaluates to whatever value was last assigned to it), or expressions (such as 2 + x, which evaluates to the value of x plus 2)..
Programmers don’t tend to talk about l-values or r-values much, so it’s not that important to remember the terms. The key takeaway is that on the left side of the assignment, you must have something that represents a memory address (such as a variable). Everything on the right side of the assignment will be evaluated to produce a value.
Uninitialized variables
Unlike some programming languages, C/C++ does not initialize variables to a given value (such as zero) automatically (for performance reasons). Thus when a variable is assigned to a memory location by the compiler, the default value of that variable is whatever garbage happens to already be in that memory location! A variable that has not been assigned a value is called an uninitialized variable.
Note: Some compilers, such as Visual Studio, will initialize the contents of memory when you’re using a debug build configuration. This will not happen when using a release build configuration.
Uninitialized variables can lead to interesting (and by interesting, we mean unexpected) results. Consider the following short program:
In this case, the computer will assign some unused memory to x. It will then send the value residing in that memory location to
A couple of notes if you want to run this program yourself: assign values to variables when they are defined. C++ makes this easy by letting you assign values on the same line as the declaration of the variable:
This ensures that your variable will always have a consistent value, making it easier to debug if something goes wrong somewhere else.
Rule: Assign values to your variables when you define them.
Quiz
What values does this program print?
Quiz Answers
To see these answers, select the area below with your mouse.
1) Show Solution
2) Show Solution
3) Show Solution
4) Show Solution
5) Show Solution
The Code:
#include “stdafx.h”
#include
int main()
{
using namespace std;
cout > x; // read number from console and store it in x
cout
It Dosent Work
When you use the cout call from the output stream the directional indicator needs to be < .
The > is for the cin call from the library.
You forgot to initialize x (ie. x = 7;)! I also think it is better if you put using namespace std; OUTSIDE main, to make it global.
I disagree. This can very easily in larger programs cause cryptic errors from name conflicts. Keeping using namespace within functions limits it’s scope, and thus limits its potential for causing problems. The safest, though, is to simply always refer to the namespaces, i.e. “std::cout << x” instead.
When i try and run the code to enter a number and have it be displayed it isn’t working right. A box opens and it asks my number and i type it in and the box just closes. Not sure what im doing wrong.
Try the following Kyle, it will surely work:
Ravi..
No, unfortunately it will not. His problem was that the program closed immediately after input. It is most likely because he has an IDE which breaks program execution immediately after main() returns 0. As such, he would need to either use a pause function such as system(“PAUSE”) to prompt the user to press enter, before the program breaks execution.
system(“pause”) may work on some systems (e.g. windows), but not on others.
A better (platform independent) solution is presented in section 0.7 -- A few common cpp problems.
It doesent Work.
When is Try it says
inter number here i enter the number and the Prg Closes
Lol, which IDE and which OS are you using? Under Windows, you can use a function called system(“PAUSE”) in order to pause the program before it goes on (in your case, exits).
In your case, you then first need to write the following in the beginning of the program:
This will include the C standard library into your program.
Then, before the return statement in main(), add system(“PAUSE”), as such:
That should do it. However, the bad thing here is that I think this works ONLY on Windows…not good! Also, I have heard that the system() function is very unsafe and should generally be avoided in professional projects, which is perhaps not so important here because you are just studying.
Hope that helps! If you need more help you can mail me (csvanefalk@hushmail.me) or of course ask the owner of the site (Alex). Me and Alex are not affiliated in any way, I would just like to help out Dont forget to give the props to Alex for his great site though!:
//for terminating the application
cout < > exitapp;
cout < < "terminating" <).
This is feature of building debug C++ software with Visual Studio. Anything you don’t initialise yourself is set to 0xCCCCCCCC (interpreted as -858993460 if it’s an int).
Try switching the build type from debug to release, and the value will be truly uninitialised and may change each time you run it..
see your cout <> This seems to be wrong
You cuold have probably went into a little more detail about those 2 functions but you did a good job of getting us on the right track…to start with.
Try to use system() as small as possible. It will be better (in our situation) to use getch(); whicl allocated at conio.h
conio.h is not part of the C++ standard set of libraries, and is not included with all compilers. Consequently I would recommend avoiding its use whenever possible.
Would this work? thank you!
hey fluxx,
As soon as i saw your code i went at it trying to fix it. and to my pleasent suprize, i got it working.
here is the perfected code:
first of all, the whole “int caculate” part was compelely useless and unessary. second, “useing namespace std;” is suppost to be affter “int main ()”. third, many of your slash brackats are wrong, when useing cout, all slash brackets are facing the left . About the “system (“puase”)” part near the end, depending on what compiler you are useing you may not need it to be there. i’m useing a compiler that requires me to input a puase code. but even if your compiler dose not need it, it shoulden’t hurt anything.
Proof that ive actually learned something from this tutorial although in c I can make it so you can type booth the numbers on the same line but Im still learning both languages at the same time XD
I made this
And it worked!!!
O_o
I suppose a kind compiler will accept that. Kind of… unconventional though.
Hi alex i would like to ask you somthing when i put:
int x;
x = 5
it gives me this error 25 D:\Dev-Cpp\main.cpp expected constructor, destructor, or type conversion before ‘=’ token
and i am greatly confused plz help
Thankz
Justin
C++ learner
I don’t see anything wrong there, except that you don’t have a semicolon after x=5.
So, it is optimal to use the minimum amount of variables, when creating a program, to make it ‘light’ on resources (RAM)?
Only if you have a really huge number of variables (eg. in the thousands). Otherwise it won’t make much difference.
dude ur pciture is the funniest thing i have EVER seen
even 8 years later
Hey Alex, great site you have here! I was taking a C++ class years ago, but as soon as we got to pointers I gave up. Since then, I have increased my knowledge a bit, at least with python / javascript, so I figured I would give C++ another go. Anyways, im learning a lot more here then I did in school, so thanks for the site!
Also, as far as pausing is concerned, I read this technique somewere -
They said their reasoning is it would be cross platform compilable, because pause.exe is windows specific, and also if someone / something were to tamper with pause.exe, executing pause.exe could be dangerous.
It seems to work well, what are your thoughts / opinions on it?
It’ll work in the majority of cases, and yes, it’s better than using pause.exe.
The only time it’ll fail is if there are extra characters in the input buffer -- _getch() will read them and not stop for more input.
I present a slightly improved version of this in lesson 0.7 -- a few common cpp problems that fixes that particular issue.
Sadly enough, the pausing issue is by far the most common topic on this site.
Thank you who ever wrote this. Gave a very well explanation on wtf was going on. C is similar but cpp makes variables much simpler
Hi Alex, i am new to C++, please could you explain to me why you used the following lines:
y = 4; // 4 evaluates to 4, which is then assigned to y
y = 2 + 5; // 2 + 5 evaluates to 7, which is then assigned to y
as later you say that y=7 which it does …but if y=4 ..then y = 2 + 5 = 7
why did we have to use y = 4 ?
regards,
Jason
The idea was to show that if you re-assign a value to Y, then it will change.
Alex,
do this #include alone work?
y they r nt giving anything aftr tht?
what does #include alone mean?
Thanks
#include by itself means nothing, and isn’t valid C++. The compiler will throw an error.
Alex, you are amazing. Thank you so much for writing these tutorials.
I’ve spent almost two hours reading (and re-reading until I made sure I understood what you are trying to say) chapter 1.3 and below. That might seem like a lot of time, but I want to know 100% what I’m doing.
I’m 14 years old and one day I’d love to work at a job having to do with programming (I’m looking at Valve Software right now). I knew nothing at all about C++, but very little Java, so I thought I should start here. Hopefully these tutorials will give me a good start, and I will continue to learn and practice C++ until I reach my goal. I understand that making games with C++ may be very different from what you’re teaching, but like I said, I’m hoping these tutorials will give me a good start.
Excuse my typing, it’s 2:40 AM and I’m a bit tired. I remembered what you mentioned at the beginning of the tutorial about being tired and/or unhappy.
Can’t wait for tomorrow!
Ok so if your values are assigned to a random memory address if we make the value just x then how will you find it?
We don’t need to. We call the variable by name(x), and the program itself keeps track of where in memory the variable points.
I keep getting an error message: error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
and error C2065: ‘cout’ : undeclared identifier
and error C2065: ‘endl’ : undeclared identifier
I don’t know why the first one getting numbers worked fine but this one does not at all, all i tried to do was erase the old stuff and enter the new stuff.
You forgot the
You just have:
It doesn’t seem to like words. Whenever you type your name in it gives you a bunch of numbers back… is there anything I can do?
There are several variable types in C++, in this case you’re declaring an integer variable(a variable that only stores numbers) so when you’re trying to output that variable it gives you crazy stuff.
Hello, Jack you wrote this.
#include
#include
int main()
{
using namespace std;
cout << "Please enter your age:" <> x;
cout << "Please enter your name:" << endl;
int y;> y;
cout << "Hello " << y << ", you are " << x << "-years-old." << endl;
return 0;
}
All you have to do is change (int y; to char y [20];) I dont know thats this is the best way but it works for me.
Sorry, I forgot the HTML tags lets try again.
Hello, Jack you wrote this code.
I hope I used the tags right if not sorry.
I’ve got a problem nobody else seems to have. I’m following this tutorial with both an IDE and a text editor/command terminal. I’m running Ubuntu 10.04 with Qt Creator for an IDE, and gedit for an editor.
When I compile the gedit version of the program manually using “g++ -o first first_C_prog.cpp” it runs and works just fine.
When I build essentially the same code in the IDE it builds fine and runs but when I put in a number and hit enter it just goes to a new line. It doesn’t display anything back to the screen and keeps running, I have to kill it manually.
Here’s the code, the only difference is in the manually compiled version I remove the #include Qtcore (seems like the same thing as stdafx.h).
I’m going to dig into the IDE help next, and see if I can figure it out. I’m an engineering student and have been programming extensively in Fortran, so an editor and terminal is just fine by me, but I think an IDE is going to be essential if I want to make a jump to GUI applications.
The professors say “if you can program in Fortran you can program in anything”, and it seems like C++ is the backbone of just about everything. Most people don’t care about things like Romberg integration or finite difference in a 3d matrix they just want a pretty window on their computer screen that gives them an answer. So, I’m off to learn C++ and this is the best tutorial I’ve found, thanx Alex.
Anybody have suggestions on how to make this IDE behave?
When assigning a number to “x” I can’t assign the number “9999999999” to it. I figure that it is too large of a number. Is there a way to get around this?
hi sega,
i have newly registered today only.
and i have found this great website to learn c++
all the credit to alex
please check if my solution suits your problem
double x = 9999999999;
cout << setprecision(16);
cout << "value =" << x;
Use the type “long” instead of “int”. We cover this (and other types) in more detail in lesson 2.4 -- Integers.
When I run this with Visual C++ 2008, the console opens up and it doesn’t say anything. Only says:
Press Enter to continue…
should be in between the brackets in main()
Try it out 😉
Why doesnt this work?? have tried to change some functions but it is taken from the solution from question 5.
#include “StdAfx.h”
#include
int doubleNumber(int x)
{
return 2 * x;
}
int main()
{
using namespace std;
int x;
cin >> x;
cout << doubleNumber(x) <> x;
x = doubleNumber(x);
cout << x <---- Build started: Project: igne, Configuration: Debug Win32 ----
1> igne.cpp
1>c:\users\mathias\desktop\projects\igne\igne\igne.cpp(24): error C2084: function ‘int main(void)’ already has a body
1> c:\users\mathias\desktop\projects\igne\igne\igne.cpp(13) : see previous definition of ‘main’
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
The following is my code :
#include “stdafx.h”
#include
int doubleNumber(int x)
{
return 2 * x;
}
int _tmain(int argc, _TCHAR* argv[])
{
using namespace std;
int x;
cin >> x;
cout << doubleNumber(x)<<endl;
x = doubleNumber(x);
cout << x<<endl;
return 0;
}
By the way,maybe your problem is the "main" function,please check your code ,and make sure there's just one main function.
Good luck!
Sounds like you have function main() declared twice, once at line 13 and once at line 24.
When I run this program it looks like I input a number and always get output of 0.
It should take the user input in function input1 and save it to variable a. Then return a to main to be cout. I added a cout in input1 after the user input to see if the user’s inputs was being stored as a. It was. It seems though that when a is returned to main a is being reset to 0.
you are printing the local copy of ‘a’ and not the return value. The local copy of ‘a’ is initialized to 0 and not changed anywhere in the main. hence 0 is displayed.
solution:
update the local copy of ‘a’ with the return value.
a = input1(a);
cout << a;
Or simply pass the variable to input1() by reference instead of by value. Like this:
#include <iostream>
void input1(int& a)
{
using namespace std;
cin >> a;
}
int main()
{
using namespace std;
int a = 0;
input1(a);
cout << a;
return 0;
}
What does the l in l-value and the r in r-value stand for? right and left?
…also I don’t get how I can go as far as to copy the thing I was supposed to do exactly and there are build errors or something. It seem to do the exact same thing the last program did…
…what does cout stand for? what does cin stand for? why is << sometimes facing one way and sometimes facing another without an obvious reason?
1) Yes, r-value stands for right value, and l-value stands for left value.
2) What errors are you talking about? Did you copy only the code without the line numbers? did you remove the VS part?
It’s quite possible that the author had some typos, but it might be a problem on your end too.
3) c - standard (don’t ask me), out - output, in - input. As for ‘>>’ and ‘<<' - I can't really explain why is that.
Hi after several attempts of my program not running after question # 1 on the quiz I finally got it to run by using:
#include "stdafx.h"
#include <iostream>.
Declaring a variable as “int (a)” is invalid, and your compiler should complain.
I am so glad to find your website. There is a very logical rationale behind your explanation which makes it simpler and at the same time joyful to learn.
Many thanks for all the hard and smart work.
when i compiled the program that uses the cin cout. i enter the number then press enter and suddenly the program closes. and this is the code i compiled.please tell me if there is anything wrong with it. (im using code blocks but on windows).
#include
int variables ()
{
using namespace std;
cout <> b;
int e;
e = b*10;
int l;
l = e/100;
int a;
a = e+b;
int d;
d = l+e;
int s;
s = 2*(d-a);
int m;
m = b+l;
cout << b << e << l << a << d << s << m;
}.
Thank you for these tutorials, they are straight forward and include what you have to know. By the time I finish all of these sections should I be able to program games like pingpong?″, it’s evaluating it as “x = 5 - 2″, which makes a lot more sense. I’ll try to clarify this in the lesson itself.
Thank you for the answer.I wonder if it works same in C#.
It works the same way in C#..
Can you add return 0 in your example?
Fixed. Thanks!
Wow, great tutorial on variables! I have worked with C++ before but was totally unaware that uninitialized variables could slip past the compiler.
I tried this but I never got a result even after switching it to the release configuration
void doNothing(const int &x)
{
}
{
/.
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(. C++ and Java is often used concurrently in many software projects. Programmers jump back and forth between C++ and Java will find this Java-like classes very helpful. Various examples are given which demonstrate the usage of this library and the Standard C++ Library.
This document is not a textbook on C++, and there are already several excellent on-line text books on the internet. Since C++ is being used for a long time there are very large number of C++ documents/articles/tutorials on Internet. If you are new to C++ and you never programmed in C++, then it is strongly suggested that you first either read an online C++ textbook given in chapter C++ Online Textbooks or you buy a C++ book from online bookstores such as Amazon or barn.
C++ is one of the most powerful languages and will be used for a long time in the future in spite of emergence of Java or PHP-scripting. Programs which need real-time ultra fast response use C/C++. C++ runs extremely fast and is in fact 10 to 20 times FASTER than Java. Java is the "offspring" of C++. The only complaint against Java is - "Java is GOD DAMN SLOW" . Java byte-code is slower when running in a VM than the equivalent natively compiled code. Java runs faster with JIT (Just-In-Time) compiler, but it is still slower than C++. And optimized C/C++ program is about 3 to 4 times faster than Java compiled to native code with JIT compiler or ahead-of-time.
When should you use C++ and when you should use Java/PHP?
Bottom line is, you use C++:
NOTE: There are lot of improvements in Java compilers (JIT and ahead-of-time). Java programs can be compiled with GNU GCJ, GCJ is a portable, optimizing, ahead-of-time compiler for the Java programming language. It can compile - Java source code directly to native machine code, Java source code to Java bytecode (class files), and Java bytecode to native machine code.
The Java native code compiler "gnu GCJ" is very rapidly maturing and in near future everybody will be programming in Java instead of C++. Special optimizers in gnu GCJ compiler can make Java programs as fast as C++ programs. The gnu GCJ compiler is 2-3 years away in becoming the de facto compiler on all platforms (initially on Linux and then on MS Windows).
GCJ resources:
Language choice is very difficult. There are too many parameters - people, people skills, cost, tools, politics (even national politics) and influence of business-people). Development costs of Ada is half of C++ as per Stephen F. Zeigler. Ada95 is available at -
The C++ compiler is lot more complex than a C compiler and C++ programs may run bit slower than C programs. The C compiler is very mature and seasoned.++. Java programmers who jump to and from C++ to Java will like this String class.
If you want to bypass the edit-compile-debug-compile cycle of C++ then see scripting languages like PHP which can be used for web development and for general purpose programming. Scripting languages like PHP and PERL enable rapid application development. PHP has some features of object-oriented programming. PHP is at.
Since C++ is increase the productivity of programmers via different methods addressed to solve the memory defects in C++. Memory related bugs are very tough to crack, and even experienced programmers take several days or weeks to debug memory related problems. Memory bugs may do everything that char * or char [] do. One of the added benefits is that you do not have to worry about the memory problems and memory allocation at all.
The current C++ standard adopted by ISO and ANSI was first finalized in 1997, this means that not all compilers are up to pace yet, and not supporting all features - it is extremely important that you get a standard compliant C++ compiler.
Since MS Windows is quite popular for C++ development, the String class library given in this document works well and runs very well on all the versions of MS Windows i.e. MS Win XP/2000/NT/95/98/ME. The C++ compilers for MS Windows are:
In a GNU world, you will always be best off with GCC (GNU Compiler Collection), GCC is distributed with most Linux distributions, FreeBSD and most other UNIX clones. The GCC homepage is located at. The latest version of GCC (3.0) is one of the most standards compliant compilers out there.
The string class is the one of the most vital objects in programming, and string manipulations are most extensively used. There is a lot of varieties of string classes. Of course, you can build your own string class by simply inheriting from these string classes -
As mentioned above, you can build your own custom string class from the pre-built classes by single or multiple inheritance. In this section we will build a sample custom string class by using multiple inheritance, inheriting the standard C++ library string class and the String class presented in Appendix A.
Start by downloading the sample file 'string_multi.h' from Appendix A .
That file is reproduced below:
// ****************************************************************** // Sample program to demonstrate constructing your own string class // by deriving from the String class and stdlib's "string" class // ****************************************************************** #ifndef __STRING_MULTI_H_ALDEV_ #define __STRING_MULTI_H_ALDEV_ #include <string> #include "String.h" #include "StringBuffer.h" #ifdef NOT_MSWINDOWS #else using namespace std; // required for MS Visual C++ compiler Version 6.0 #endif // Important Notes: In C++ the constructors, destructors and copy // operator are NOT inherited by the derived classes!! // Hence, if the operators like =, + etc.. are defined in // base class and those operators use the base class's contructors // then you MUST define equivalent constructors in the derived // class. See the sample given below where constructors mystring(), // mystring(char[]) are defined. // // Also when you use operator as in atmpstr + mstr, what you are really // calling is atmpstr.operator+(mstr). The atmpstr is declared a mystring class mystring:public String, string { public: mystring():String() {} // These are needed for operator=, + mystring(char bb[]):String(bb) {} // These are needed for operator=, + mystring(char bb[], int start, int slength):String(bb, start, slength) {} mystring(int bb):String(bb) {} // needed by operator+ mystring(unsigned long bb):String(bb) {} // needed by operator+ mystring(long bb):String(bb) {} // needed by operator+ mystring(float bb):String(bb) {} // needed by operator+ mystring(double bb):String(bb) {} // needed by operator+ mystring(const String & rhs):String(rhs) {} // Copy Constructor needed by operator+ mystring(StringBuffer sb):String(sb) {} // Java compatibility mystring(int bb, bool dummy):String(bb, dummy) {} // for StringBuffer class int mystraa; // customizations of mystring private: int mystrbb; // customizations of mystring }; #endif // __STRING_MULTI_H_ALDEV_
All the programs, examples are given in Appendix of this document. You can download as a single tar zip, the String class, libraries and example programs from
You may a have question of mis-trust go here and click on 'Source code for!!
Take have the same name as that of Java language's String class. The function names and the behaviour is exactly the"; ....... }
C++ and Java are often used concurrently in many software projects. Programmers who jump back and forth between C++ and Java will find this string class very helpful.
In C++ (or any object oriented language), you just read the "class data-structure" (i.e. interface) to begin using that class. You just need to understand the interface and not the implementation of the interface. In case of String class, you just need to read and understand the String class in String.h file. You do not need to read the entire implementation (String.cpp) in order to use String class. The object oriented classes are real time saver and they very neatly hide the implementation.
(In object oriented Java language there is the equivalent called 'interface' , which hides the implementation details.)
Given below is the sample String.h file and see also Appendix A String.h
The String.h has more than 200 string manipulation functions but below only few functions are shown as sample.
// I compiled and tested this string class on Linux (Redhat 7.1) and // MS Windows Borland C++ version 5.2 (win32). This should also work // using MS Visual C++ compiler class String { public: String(); virtual ~String(); // Functions below imitate Java language's String object unsigned long length(); char charAt(int where); void getChars(int sourceStart, int sourceEnd, char target[], int targetStart); char* toCharArray(); char* getBytes(); bool equals(String str2); bool equals(char *str2); bool equalsIgnoreCase(String str2); bool regionMatches(int startIndex, String str2, int str2StartIndex, int numChars); bool regionMatches(bool ignoreCase, int startIndex, String str2, int str2StartIndex, int numChars); String toUpperCase(); String toLowerCase(); bool startsWith(String str2); bool startsWith(char *str2); bool endsWith(String str2); bool endsWith(char *str2); int compareTo(String str2); int compareTo(char *str2); int compareToIgnoreCase(String str2); int compareToIgnoreCase(char *str2); int indexOf(char ch, int startIndex = 0); int indexOf(char *str2, int startIndex = 0); int indexOf(String str2, int startIndex = 0); int lastIndexOf(char ch, int startIndex = 0); int lastIndexOf(char *str2, int startIndex = 0); int lastIndexOf(String str2, int startIndex = 0); String substring(int startIndex, int endIndex = 0); String replace(char original, char replacement); String replace(char *original, char *replacement); String trim(); String concat(String str2); String concat(char *str2); String concat(int bb); String concat(unsigned long bb); String concat(float bb); String concat(double bb); String reverse(); String deleteCharAt(int loc); String deleteStr(int startIndex, int endIndex); String valueOf(char ch) {char aa[2]; aa[0]=ch; aa[1]=0; return String(aa);} String valueOf(char chars[]){ return String(chars);} String valueOf(char chars[], int startIndex, int numChars); String valueOf(bool tf) {if (tf) return String("true"); else return String("false");} String valueOf(int num){ return String(num);} String valueOf(long num){ return String(num);} String valueOf(float num) {return String(num);} String valueOf(double num) {return String(num);} // See also StringBuffer class in this file given below // ---- End of Java like String object functions ----- ////////////////////////////////////////////////////// // List of additional functions not in Java ////////////////////////////////////////////////////// String ltrim(); String rtrim(); /////////////////////////////////////////////////////////////////////// // More than 200 string manipulation functions are provided (see the // "Download String" section) but only few functions are shown here. /////////////////////////////////////////////////////////////////////// void ensureCapacity(int capacity); void setLength(int len); void setCharAt(int where, char ch); int parseInt(String ss) {return ss.toInteger();} int parseInt(char *ss) {String tmpstr(ss); return tmpstr.toInteger();} long parseLong(String ss) {return ss.parseLong();} long parseLong(char *ss) {String tmpstr(ss); return tmpstr.parseLong();} float floatValue() {return (float) toDouble(); } double doubleValue() {return toDouble(); } // All Operators ... String operator+ (const String rhs); String operator+= (const String rhs); String operator= (const String rhs); bool operator== (const String rhs); bool operator!= (const String rhs); char operator [] (unsigned long Index) const; ostream operator << (ostream Out, const String str2); istream operator >> (istream In, String str2); bool String::operator< (const char rhs); /////////////////////////////////////////////////////////////////////// // More than 200 string manipulation functions are provided (see the // "Download String" section) but only few functions are shown here. /////////////////////////////////////////////////////////////////////// };
C++ and Java are often used concurrently in many software projects. Programmers jump back and forth between C++ and Java will find this stringbuffer class very helpful.
// // Author : Al Dev Email: alavoor[AT]yahoo.com // //(); String); };
C++ and Java is often used concurrently in many software projects. Programmers jump back and forth between C++ and Java will find this stringtokenizer class very helpful.
// // Author : Al Dev Email: alavoor[AT]yahoo.com // // Imitate Java's StringTokenizer class // provided to compile Java code in C++ and vice-versa class StringTokenizer: public String { public: StringTokenizer(String str); StringTokenizer(String str, String delimiters); StringTokenizer(String str, String delimiters, bool delimAsToken); ~StringTokenizer(); int countTokens(); bool hasMoreElements(); bool hasMoreTokens(); String nextElement(); // in Java returns type 'Object' String nextToken(); String nextToken(String delimiters); };
While references occurrence of Ben was found at: " << position << endl;
This code makes a case sensitive search for 'Ben' in the string, and puts.
C++.
In C, you use malloc(), free() and variants of malloc() to allocate and free memory, but these functions have their pitfalls. Therefore C++ introduced operators for handling memory, these operators are called new and delete. These operators allocates and frees memory from the heap (or sometimes called the free store) at runtime.
In C++, you should always use new and delete unless you're really forced to use malloc() and free(). But be aware that you cannot mix the two. You cannot malloc() memory, and then delete it afterwards, likewise you can't "new" memory, and then free it with free().
The delete and new operators in C++ are much better than the malloc and free functions of C. Consider using new and zap (delete function) instead of malloc and free as much as possible.
To make delete operators even more cleaner, make a Zap() inline function. Define a zap() function like this:
// Put an assert to check if x is NULL, this is to catch // program "logic" errors early. Even though delete works // fine with NULL by using assert you are actually catching // "bad code" very early // Defining Zap using templates // Use zap instead of delete as this will be very clean template <class T> inline void zap(T & x) { {assert(x != NULL);} delete x; x = NULL; } // In C++ the reason there are 2 forms of the delete operator is - because // there is no way for C++ to tell the difference between a pointer to // an object and a pointer to an array of objects.. This will ensure that even if multiple zap()'s are called on the same deleted pointer then the program will not crash. Please see the function zap_example() in example_String.cpp click on 'Source code of C++'.
// See zap_example() in example_String.cpp zap(pFirstname); //zap(pFirstname); // no core dumps. Because pFirstname is NULL now //zap(pFirstname); // no core dumps. Because pFirstname is NULL now zap(pLastname); zap(pJobDescription); int *iiarray = new int[10]; zaparr(iiarray);
There is nothing magical about this, it just saves repetetive code, saves typing time and makes programs more readable. The C++ programmers often forget to reset the deleted pointer to NULL, and this causes annoying problems causing core dumps and crashes. The zap() takes care of this automatically. Do not stick a typecast in the zap() function -- if something errors out on the above zap() function it likely has another error somewhere.
Also my_malloc() , my_realloc() and my_free() should be used instead of malloc(), realloc() and free(), as they are much cleaner and have additional checks. For an example, see the file "String.h" which is using the my_malloc() and my_free() functions.
WARNING : Do not use free() to free memory allocated with 'new' or 'delete' to free memory allocated with malloc. If you do, then results will be unpredictable.
See the zap examples in example_String.cpp click on 'Source code of C++'.
Try to avoid using malloc and realloc as much as possible and use new and zap(delete). But sometimes you may need to use the C style memory allocations in C++. Use the functions my_malloc() , my_realloc() and my_free(). These functions do proper allocations and initialisations and try to prevent memory problems. Also these functions (in DEBUG mode) can keep track of memory allocated and print total memory usage before and after the program is run. This tells you if there are any memory leaks.
The my_malloc and my_realloc is defined as below. It allocates little more memory (SAFE_MEM = 5) and initializes the space and if it cannot allocate it exits the program. The 'call_check(), remove_ptr()' functions are active only when DEBUG_MEM is defined in makefile and are assigned to ((void)0) i.e. NULL for non-debug production release. They enable the total-memory used tracing.
void *local_my_malloc(size_t size, char fname[], int lineno) { size_t tmpii = size + SAFE_MEM; void *aa = NULL; aa = (void *) malloc(tmpii); if (aa == NULL) raise_error_exit(MALLOC, VOID_TYPE, fname, lineno); memset(aa, 0, tmpii); call_check(aa, tmpii, fname, lineno); return aa; } char *local_my_realloc(char *aa, size_t size, char fname[], int lineno) { remove_ptr(aa, fname, lineno); unsigned long tmpjj = 0; if (aa) // aa != NULL tmpjj = strlen(aa); unsigned long tmpqq = size + SAFE_MEM; size_t tmpii = sizeof (char) * (tmpqq); aa = (char *) realloc(aa, tmpii); if (aa == NULL) raise_error_exit(REALLOC, CHAR_TYPE, fname, lineno); // do not memset memset(aa, 0, tmpii); aa[tmpqq-1] = 0; unsigned long kk = tmpjj; if (tmpjj > tmpqq) kk = tmpqq; for ( ; kk < tmpqq; kk++) aa[kk] = 0; call_check(aa, tmpii, fname, lineno); return aa; }
An example on usage of my_malloc and my_free as below:
char *aa; int *bb; float *cc; aa = (char *) my_malloc(sizeof(char)* 214); bb = (int *) my_malloc(sizeof(int) * 10); cc = (float *) my_malloc(sizeof(int) * 20); aa = my_realloc(aa, sizeof(char) * 34); bb = my_realloc(bb, sizeof(int) * 14); cc = my_realloc(cc, sizeof(float) * 10);
In C/C++ Garbage Collection is not a standard feature and hence allocating and freeing storage explicitly is difficult, complicated and is error-prone. The Garbage Collection (GC) is not part of the C++ standard because there are just so many ways how one could implement it; there are many GC techniques, and deciding to use a particular one would not be good for certain programs. Computer scientists had designed many GC algorithms, each one of them catering to a particular problem domain. There is no one single generic GC which will tackle all the problem domains. As a consequence, GC is not part of C++ standard, they just left it out. Still, you always have the choice of many freely available C++ libraries that do the job for you.
Visit these sites:
You must use const at every opportunity. The const is your most powerful anti-crash weapon. An additional benefit is that it makes your code self-documenting. For instance, look at this:
const("James", "Bond 007"); strcat(pchName, " jumps out of the plane and parachutes down");("Big galaxies", "Big stars");
Even if you declared pchName as a const char *, the moment you modified its contents with strcat() you'd get a compile error. The const keyword helps the programmer keep any errors localized, thus greatly reducing the likelihood of side-effect errors.
Forget you ever knew printf(). Use cout <<. Of course, scanf() was flirting with disaster even in the rough and ready C days. Use cin >>, or make your own input routines or classes. What about that wonderful sprintf()? Instead of this:
#include <iostream.h> #include <stdio.h> /* . . . */ char myaString[100]; sprintf(myaString, "%s, %s %c", myaLname, myaFname, *myaMname); cout << myaString << '\n';
#include <iostream.h> #include <strstream.h> /* . . . */ ostrstream ost; ost << myaLname << ", " << myaFname << " " << *myaMname; ost.put(0); //null terminate the string cout cout << ost.str() << '\n';
Pointers are not required for general purpose programming. In modern languages like Java there is no support for pointers (Java internally uses pointers). Pointers make the programs messy and programs using pointers are very hard to read.
Avoid using pointers as much as possible and use references. Pointers are really a great pain. It is possible to write an application without using pointers. You should pointers only in those cases where references will not work.
A reference is an alias; when you create a reference, you initialize it with the name of another object, the target. From the moment on, the reference acts as an alternative name of the target, and anything you do to the reference is really done to the target.
Syntax of References: Declare a reference by writing the type, followed by the reference operator (&), followed by the reference name. References MUST be initialized at the time of creation. For example -
int weight; int & rweight = weight; DOG aa; DOG & rDogRef = aa;
Do's of references -
Do not's of references -
Finding the exact source to a bug can be a troublesome process, however there is several techniques used for debugging:
Sites to help debugging:
To debug any C++ or C programs include the file debug.h and in your 'Makefile' define DEBUG_STR, DEBUG_PRT, DEBUG_MEM to turn on the traces from the debug.h functions. When you remove the '-DDEBUG_STR' etc.. then the debug function calls are set to ((void)0) i.e. NULL, hence it has no impact on final production release version of project. You can generously use the debug functions in your programs and it will not increase the size of production executable.
See the file debug.cpp for implementation of debug routines.
And see the file my_malloc.cpp for a sample which uses debug.h and debug functions.
See the sample Makefile .
When programming C++, it is a good idea to used to an editor or an IDE. Most programmers have their own favourites, and it's a religious discussion on which is better.
You can choose to use an IDE (Integrated Development Environment), which is an application with embedded editor, compiler, documentation and more. And then there is the stand-alone editors, which some people like better.
The following IDE tools (Integrated Development Environment) are available for C++:
The problem with IDE's is many times their editors have a big lack of functionality. Therefore many people want a powerful editor alone, and then supply compiler next to it.
Of powerful editors, vim and emacs can be mentioned. They are both available for most platforms - and they support syntax highlighting and other things which will make you more efficient.
Other editors include UltraEdit(win32 only) and EditPlus(win32 only).
There++
Coding
The or PIKE will become most widely used scripting language as it is object oriented and it's syntax is very identical to that of C/C++.
Programming productivity will increase by five times by using the PHP or Pike C++ scripting language. And PHP or PIKE is very useful for 'proof of concept' and developing prototypes rapidly.
PHP is exploding in popularity for general purpose programming and for web development. PHP may become the most widely used scripting language in near future..
Templates:
Please liberty type. In particular it is not necessary to know how big you want the vector to be when you declare it, you can add new elements to the end of a vector using the push_back function. (In fact the insert function allows you (separated true. difference.
This section is written by Ryan Teixeira and the document is located here .
Multi threaded programming is becoming ever more popular. This section presents a design for a C++ class that will encapsulate the threading mechanism. Certain aspects of thread programming, like mutexes and semaphores are not discussed here. Also, operating system calls to manipulate threads are shown in a generic form.
To understand threads one must think of several programs running at once. Imagine further that all these programs have access to the same set of global variables and function calls. Each of these programs would represent a thread of execution and is thus called a thread. The important differentiation is that each thread does not have to wait for any other thread to proceed. All the threads proceed simultaneously. To use a metaphor, they are like runners in a race, no runner waits for another runner. They all proceed at their own rate.
Why use threads you might ask. Well threads can often improve the performance of an application and they do not incur significant overhead to implement. They effectively give good bang for a buck. Imagine an image server program that must service requests for images. The program gets a request for an image from another program. It must then retrieve the image from a database and send it to the program that requested it. If the server were implemented in a single threaded approach, only one program could request at a time. When it was busy retrieving an image and sending it to a requestor, it could not service other requests. Of course one could still implement such a system without using threads. It would be a challenge though. Using threads, one can very naturally design a system to handle multiple requests. A simple approach would be to create a thread for each request received. The main thread would create this thread upon receipt of a request. The thread would then be responsible for the conversation with the client program from that point on. After retrieving the image, the thread would terminate itself. This would provide a smooth system that would continue to service requests even though it was busy servicing other requests at the same time.. This is what we will use as the entry point. There is a gotcha here though. Static member functions do not have access to the this pointer of a C++ object. They can only access static data. Fortunately, there is way to do it. Thread entry point functions take a void * as a parameter so that the caller can typecast any data and pass in to the thread. We will use this to pass this to the static function. The static function will then typecast the void * and use it to call a non static member function.
It should be mentioned that we are going to discuss a thread class with limited functionality. It is possible to do more with threads than this class will allow.
class Thread { public: Thread(); int Start(void * arg); protected: int Run(void * arg); static void * EntryPoint(void*); virtual void Setup(); virtual void Execute(void*); void * Arg() const {return Arg_;} void Arg(void* a){Arg_ = a;} private: THREADID ThreadId_; void * Arg_; }; Thread::Thread() {} int Thread::Start(void * arg) { Arg(arg); // store user data int code = thread_create(Thread::EntryPoint, this, & ThreadId_); return code; } int Thread::Run(void * arg) { Setup(); Execute( arg ); } /*static */ void * Thread::EntryPoint(void * pthis) { Thread * pt = (Thread*)pthis; pthis->Run( Arg() ); } virtual void Thread::Setup() { // Do any setup here } virtual void Thread::Execute(void* arg) { // Your code goes here }
It is important to understand that we are wrapping a C++ object around a thread. Each object will provide an interface to a single thread. The thread and the object are not the same. The object can exist without a thread. In this implementation, the thread does not actually exist until the Start function is called.
Notice that we store the user argument in the class. This is necessary because we need a place to store it temporarily until the thread is started. The operating system thread call allows us to pass an argument but we have used it to pass the this pointer. So we store the real user argument in the class itself and when the execute function is called it can get access to the argument.
Thread(); This is the constructor.
int Start(void * arg); This function provides the means to create the thread and start it going. The argument arg provides a way for user data to be passed into the thread. Start() creates the thread by calling the operating system thread creation function.
int Run(void * arg); This is a protected function that should never be tampered with.
static void * EntryPoint(void * pthis); This function serves as the entry point to the thread. It simply casts pthis to Thread * and
virtual void Setup(); This function is called after the thread has been created but before Execute() is called. If you override this function, remember to call the parent class Execute().
virtual void Execute(void *); You must override this function to provide your own functionality.
To use the thread class, you derive a new class. You override the Execute() function where you provide your own functionality. You may override the Setup() function to do any start up duties before Execute is called. If you override Setup(), remember to call the parent class Setup().
This section presented an implementation of a thread class written in C++. Of course it is a simple approach but it provides a sound foundation upon which to build a more robust design.
If you have comments or suggestions, email to Ryan Teixeira
Visit the following sites for C++ Utilities
Use the following memory debugging tools supersedes.
You can download all programs as a single tar.gz file from Download String and give the following command to unpack
bash$ man tar bash$ tar ztvf C++Programming-HOWTO.tar.gz This will list the table of contents bash$ tar zxvf C++Programming-HOWTO.tar.gz This will extract the files
The())
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I have a Proxy implementation for JDK 1.2 that I could contribute
(e.g. I have copyright), either as a starter implementation or for
reference. It's the one used by OpenEJB for JDK 1.2 support. But it
doesn't use BCEL. I've used BCEL a bit, enough to do everything up until
field interception, but I'm probably going to be spending my time on
JSR-88 more than this in the short term.
BTW, I'm not convinced the best way to handle CMP 2.0 is to allow
the Proxy to extend abstract classes as well as interfaces. If we have
the byte code wizardry to do the byte code mangling for the last point,
why don't we just generate non-proxy concrete subclasses of the CMP 2.0
abstract classes and ditch the reflection altogether?
Aaron
On Fri, 22 Aug 2003, Dain Sundstrom wrote:
> We are going to need some BCEL code which varies from simple to quite
> complex. If you are an expert or eager to learn, here is what we need
> (from simple to complex):
>
>
>
> Interface proxy generator -- This is a copy of java.reflection.Proxy.
> Why do we need a copy? Well I think it is a good starting point for
> the rest of the stuff, and I know we can do it better. I would like
> the proxy generator to be able to generate class names that have some
> meaning other then Proxy$24, and I think we can write code that this
> faster.
>
>
>
> Dynamic instance factory -- One slow thing we will run into with the
> proxy generator above is normally the core of the generator looks like
> this:
>
> Object getProxy(Class[] interfaces) {
> Class clazz = getProxyClass(interfaces);
> Constructor constructor = clazz.getConstructor(null);
> constructor.newInstance(null);
> }
>
> Jeremy and I did some benchmarks the other day and the call to
> newInstance on constructor is surprisingly expensive (the rest can be
> optimized out). The fastest way we found to create a class was to
> generate the byte code for an instance factory. The factory would be
> the equivalent of this Java code:
>
> public class MyProxyInstanceFactory implements InstanceFactory {
> public Object newInstance() {
> return new MyProxy();
> }
> }
>
> So the line newInstance line becomes:
>
> InstanceFactory factory = getInstanceFactory(clazz);
> return factory.newInstance();
>
> Notice this is not using a reflection call, it would raw byte code to
> create a new instance the normal java way and has the exact same cost
> as calling an interface method (duh, it is a call on an interface
> method). This is another flexibility versus speed trade off. To keep
> the factory simple, it can only create classes with no arguments. I
> used beclifier to do this, but I really don't understand BECL, so I
> would not want to commit it.
>
>
>
> Abstract class proxy generator -- We need this for the CMP 2.x
> implementation. In CMP 2.x the bean provider writes an abstract class
> and we generate a concrete sub class. I think the best way to
> implement this, is to extend the interface proxy generator above, to
> allow one of the specified interfaces to be a class. When it detects a
> real class, the proxy generator would generate a subclass of the class
> and implement any abstract methods by delegating them to an
> InvocationHandler.
>
>
>
> Field interception -- This will make CMP 1.x much easier to implement.
> In CMP 1.x, the bean provider writes a concrete class where the
> persistent fields are simple public fields of the class. If we can
> replace all byte code that access these fields with a call to the
> InvocationHandler, it will make CMP 1.x look like CMP 2.x. This
> technique is also used by JDO so it will make our JDO implementation
> (when we get to that) easier.
>
>
>
> This should be a very fun project. I'd do it myself, but I've got too
> many other things on my plate right now.
>
> -dain
>
> /*************************
> * Dain Sundstrom
> * Partner
> * Core Developers Network
> *************************/
>
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memcmp()
Compare the bytes in two buffers
Synopsis:
#include <string.h> int memcmp(cmp() function compares length bytes of the buffer pointed to by s1 to the buffer pointed to by s2.
Returns:
- < 0
- The object pointed to by s1 is less than the object pointed to by s2.
- 0
- The object pointed to by s1 is equal to the object pointed to by s2.
- > 0
- The object pointed to by s1 is greater than the object pointed to by s2.
Examples:
#include <stdio.h> #include <string.h> #include <stdlib.h> int main( void ) { char buffer[80]; int retval; strcpy( buffer, "World" ); retval = memcmp( buffer, "hello", 5 ); if( retval < 0 ) { printf( "Less than\n" ); } else if( retval == 0 ) { printf( "Equal to\n"); } else { printf( "Greater than\n"); } return EXIT_SUCCESS; }
produces the output:
Less than
Classification:
Last modified: 2014-06-24
Got questions about leaving a comment? Get answers from our Disqus FAQ.comments powered by Disqus
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Advanced mathematical operators
Posted February 27, 2013 at 02:49 PM | categories: python | tags: | View Comments
Updated March 06, 2013 at 06:29 PM
The primary library we will consider is nil, which provides many mathematical functions, statistics as well as support for linear algebra. For a complete listing of the functions available, see. We begin with the simplest functions.
import numpy as np print np.sqrt(2)
1.41421356237
1 Exponential and logarithmic functions
Here is the exponential function.
import numpy as np print np.exp(1)
2.71828182846
There are two logarithmic functions commonly used, the natural log function nil and the base10 logarithm nil.
import numpy as np print np.log(10) print np.log10(10) # base10
2.30258509299 1.0
There are many other intrinsic functions available in nil which we will eventually cover. First, we need to consider how to create our own functions.
Copyright (C) 2013 by John Kitchin. See the License for information about copying.
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A backtracking problem can usually be solved by traversing a tree, where each node represents a potential answer (in this case, each node (the variable comb) represents a combination of numbers in [1,...,n]).
The trick to make a solution to a backtracking problem faster is to traverse as few nodes as possible in the tree.
Thus, when you know that there aren't going to be any valid answers even if you traverse deeper, stop (in this case, the 3 "break" conditions prevent the algorithm from traversing deeper).
...
public class Solution {
List<List<Integer>> res; static final int MIN_NUM = 1; static final int MAX_NUM = 9; public List<List<Integer>> combinationSum3(int k, int n) { res = new LinkedList<List<Integer>>(); dfs(new ArrayList<Integer>(k), k, n, MIN_NUM); return res; } public void dfs(List<Integer> comb, int k, int n, int startNum){ if(n==0 && k==0){ res.add(new ArrayList<Integer>(comb)); } else { for(int num=startNum; num<=MAX_NUM; num++){ if(MAX_NUM-num+1 < k || // make sure that there're at least k nums between [startNum,startNum+1,..,9] k*num+(k-1)*k/2 > n || // make sure that the min sum: num+(num+1)+..+(num+k-1) is at most n MAX_NUM*k-(k-1)*k/2 < n // make sure that the max sum: 9+(9-1)+..+(9-(k-1)) is at least n ) { break; } comb.add(num); dfs(comb, k-1, n-num, num+1); comb.remove((int)(comb.size()-1)); } } }
}
...
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Aliases: readdir_r(3), readdir_r(3), readdir_r(3), readdir_r(3), readdir_r(3), readdir_r(3), readdir_r(3)
NAME
readdir - read a directory
SYNOPSIS
#include <dirent.h>
struct dirent *readdir(DIR *dirp);
DESCRIPTION:The data returned by readdir() may be overwritten by subsequent calls to readdir() for the same directory stream..
ERRORS
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7)..
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
NOTES
A directory stream is opened using opendir(3).
The order in which filenames are read by successive calls to readdir() depends on the filesystem implementation; it is (\(aq\0\(aq)..
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This is due within a few hours, and I am unable to spot what is causing the program to not work.
Any suggestions?
["""Bounce - is a game that has a ball which increases in speed when you click
on the ball. That click signals the ball to speed up, records the click as a
win for the player. Once the player has reached the maximum speed, they have
the choice to restart or finish. The ball will never leave the screen but it
has a random pattern so when you lose and start over; one can not tell where
the ball will begin at."""
import time
import random
from math import *
from graphics import *
win = GraphWin("Bounce", 500, 500)
win.setCoords(0.0, 0.0, 500, 500)
from graphics import *
import random
class Bounce(object):#class
def __init__ (self, circle):#construtor
self.circle = circle
self.wins = 0
self.speed = 2
def ball(self):
#Ball, creates the ball for the game- has its shape, path and speed
#create windown
#draw ball, red ball, starts near upper window? or random
#Print game title near top
#self.circle = Circle(Point (random.randint(0,400), random.randint(0,400)), 25)#may change
#to smaller for challenge, or adjustable size
self.circle.setFill("red")
self.circle.draw(win)
#needs move function
for i in range(100):
self.circle.move(random.randint(-100,150),random.randint(-100,175))#the move needs
#to be inside the window, make sure the numbers are different
#the move moves in one direction!
# if self.circle.getCenter().getX() > 500:
# self.circle.move(200,0)
#elif self.circle.getCenter().getY() < 500:
# self.circle.move(0,200)
# elif self.circle.getCenter().getX() < 0:
# self.circle.move(200,0)
#elif self.circle.getCenter().getY() > 0:
# self.circle.move(0, 200)
time.sleep(self.speed)# go back over the sides after everything else
#the speed is going to be added to over time after certain event
#can I get it to move in other directions
#goes off screen, due to random; but since its random I can't predict it coming back on
#use if statements to keep on screen.
def isclicked(self):
#allows the user to click the ball and increase the speed due to click.
p = win.getMouse()
X1 = self.circle.getCenter().getX()
Y1 = self.circle.getCenter().getY()
X2 = p.getX()
Y2 = p.getY()
D = sqrt(((X2-X1)**2)+((Y2-Y1)**2))#distance formula from center to click
r = self.circle.getRadius()
if D <= r:
print D
def Wins(self):
#wins, records the amount of wins one gets whenever the ball is clicked.
self.wins = self.wins + 1
self.speed = self.speed *.01
winner = str(self.wins) + str(self.speed) + "Winner"
return winner
def main():
b = Bounce(Circle(Point (random.randint(0,400),random.randint(0,400)), 25))
b.isclicked()
b.Wins()
main()
]
|
https://www.daniweb.com/programming/software-development/threads/276356/game-for-computer-science-class
|
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|
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| 470
| 69.48
|
’ll be doing end-to-end tests and checking if certain features actually work as expected. To do this, we’ll use Jest and Puppeteer (you can read about Puppeteer here).
Build a React app
We’ll be writing tests for a functional React app and see what happens when the tests pass and fail. To get started, we’ll use the create-react-app package to quickly scaffold a React app.
npx create-react-app react-puppeteer
Once the project directory has been created and installed, navigate to the newly created directory and run the command below in your terminal.
npm i --save-dev jest jest-cli puppeteer faker
Jest — a testing tool created by Facebook to test React apps or basically any JavaScript app
jest-cli — a CLI runner for Jest
Puppeteer — a Node library which provides a high-level API to control headless Chrome or Chromium over the DevTools Protocol. We’ll use this to carry out tests from a user’s perspective.
faker — a tool that helps to generate massive amounts of fake data in the browser. We’ll use it to generate data for Puppeteer.
In your
package.json file, add the following line of code in the
scripts object.
"test": "jest"
With all the necessary packages installed, you can run the React app with the command
npm start and just leave it running in the background.
Write the tests
To start off with the tests, we’ll first write a test to check if there’s a particular text on a page and also a test to see if a contact form submits successfully. Let’s start off with checking if there’s a particular text on a page.
The
App.test.js file is where we’ll be writing the tests. Jest is automatically configured to run tests on files have the word
test in them. Open up the
App.test.js and edit with the following code.
const faker = require('faker'); const puppeteer = require('puppeteer'); const person = { name: faker.name.firstName() + ' ' + faker.name.lastName(), email: faker.internet.email(), phone: faker.phone.phoneNumber(), message: faker.random.words() }; describe('H1 Text', () => { test('h1 loads correctly', async () => { let browser = await puppeteer.launch({ headless: false }); let page = await browser.newPage(); page.emulate({ viewport: { width: 500, height: 2400 }, userAgent: '' }); await page.goto(''); await page.waitForSelector('.App-title'); const html = await page.$eval('.App-title', e => e.innerHTML); expect(html).toBe('Welcome to React'); browser.close(); }, 16000); });
In the first part of the code block above,
faker and
puppeteer are both imported and we generate a bunch of data from
faker which will be used later.
The
describe function acts as a container that’s used to create a block that groups related tests into one test suite. This can be helpful if you want your tests to be organized into groups. The
test function is declared by Jest with the name of the test suite.
Inside the
test function, a browser is launched with Puppeteer with the option of
headless mode set to
false. This means that we can see the browser while testing.
browser.newPage() allows you to create a new page.
The
.emulate() function gives you the ability to emulate certain device metrics and User-agent. In the code block above, we set it to have a viewport of
500x2400.
With the page open and it’s viewport defined, we then tell it to navigate to the app we’ll be testing with the
.goto() function. The
.waitForSelector() function tells Puppeteer to hold on until the particular selector has been loaded on the DOM. Once it’s loaded, the
innerText of that selector is stored in a variable called
html.
The next line is where the real testing happens.
expect(html).toBe('Welcome to React')
In the line of code above, the Jest
expect function is set to check if the content of the variable
html is the same as
Welcome to React. As previously mentioned, we are testing if a particular text on the app is what it should be, a very straightforward test. At the end of the test, the browser is closed with the
.close() function.
Let’s now run the test, in your terminal, run the command below.
npm run test
The test would pass, therefore your command output should be the same as above. You can actually change the content of the
.App-title selector to see what would happen to failed tests.
Here, the output actually indicates both that the test failed and why it failed. In this case, the received value is not the same as the expected value.
More testing!
For the next test, we’ll simulate and test submitting a contact form on the React app.
In the React app code, open up the
App.js file and edit with the code below.
import React, { Component } from 'react'; import logo from './logo.svg'; import './App.css'; class App extends Component { constructor(props) { super(props); this.state = { fullname: '', email: '', message: '', terms: false, test: '' } this.handleChange = this.handleChange.bind(this); this.handleSubmit = this.handleSubmit.bind(this); } handleChange(event) { const target = event.target; const value = target.type === "checkbox" ? target.checked : target.value; const name = target.name; this.setState({ [name]: value }); } handleSubmit(event) { event.preventDefault(); console.log(this.state) } render() { return ( <div className="App"> <header className="App-header"> <img src={logo} <h1 className="App-title">Welcome to a React app</h1> </header> <p className="App-intro"> To get started, edit <code>src/App.js</code> and save to reload. </p> <div className="container contact-form m-t-20"> <p>Contact Form</p> <form onSubmit={this.handleSubmit}> <div className="field"> <div className="control"> <label className="label">Full Name</label> <input name="fullname" type="text" placeholder="Full Name" className="input" value={this.state.fullname} onChange={this.handleChange}/> </div> </div> <div className="field"> <div className="control"> <label className="label">Email Address</label> <input name="email" type="email" placeholder="Email Address" className="input" value={this.state.email} onChange={this.handleChange}/> </div> </div> <div className="field"> <div className="control"> <label className="label">Message</label> <textarea className="textarea" placeholder="Message here" name="message" value={this.state.message} onChange={this.handleChange}></textarea> </div> </div> <div className="field"> <div className="control"> <label className="checkbox"> <input name="terms" type="checkbox" checked={this.state.terms} onChange={this.handleChange} /> I agree to the{" "} <a href="">terms and conditions</a> </label> </div> </div> <div className="field"> <div className="control"> <label className="label"> Do you test your React code? </label> <label className="radio"> <input type="radio" name="test" onChange={this.handleChange} <input type="radio" name="test" onChange={this.handleChange} <div className="control"> <button type="submit" className="button is-link">Submit</button> </div> </div> </form> </div> </div> ); } } export default App;
The
App.js has being updated to have a contact form and the submit button simply logs the form data to the console.
Next, add the code block below to your
App.test.js file.
describe('Contact Form', () => { test('Can submit contact form', async () => { let browser = await puppeteer.launch({ headless: false, devtools: true, slowMo: 250 }); let page = await browser.newPage(); page.emulate({ viewport: { width: 500, height: 900 }, userAgent: '' }); await page.goto(''); await page.waitForSelector('.contact-form'); await page.click("input[name=fullname]"); await page.type("input[name=fullname]", person.name); await page.click("input[name=email]"); await page.type("input[name=email]", person.email); await page.click("textarea[name=message]"); await page.type("textarea[name=message]", person.message); await page.click("input[type=checkbox]"); await page.click("input[name=question]"); await page.click("button[type=submit]"); browser.close(); }, 9000000); });
This test suite is similar to the one above, the
puppeteer.launch() function launches a new browser along with some config. In this case, there are two additional options,
devtools which displays the Chrome devtools and
slowMo which slows down Puppeteer processes by the specified amount of milliseconds. This allows us to see what is going on.
Puppeteer has the
.click and
.type actions that actually simulate the whole process of clicking on input fields and typing in the values. The details for the form fields are gotten from
faker which set in the
person object earlier.
This test suite fills the contact form and tests if the user can actually submit this form successfully.
You can run the
npm run test command in your terminal and you should a Chrome browser open and watch the actual testing process.
For the next set of tests, we’ll write tests to assert the following:
— Users can login
— Users can logout
— Users are redirected to the login page for unauthorized view
— Nonexistent views/route returns a 404 page
The tests above are end to end tests that are carried out from the user’s perspective. We are checking if a user can actually use the app for the most basic things.
To carry out these tests, we’ll need a React app. We’ll use Robin Wieruch’s React Firebase Authentication Boilerplate code on GitHub. It ships with a built in authentication system, all that needs to be done is creating a Firebase project and adding the Firebase keys.
I modified the code a bit and added some selectors and IDs that makes the app suitable for testing. You can see that here on GitHub. Go ahead and clone the GitHub repo to your local system and run the following commands.
npm i
npm start
Don’t forget to create a Firebase account and add your credentials in the
src/firebase/firebase.js file.
Let’s go ahead with writing tests for the React app. Once again, we’ll need to install
jest
faker, and
puppeteer, also a
App.test.js file is needed.
npm i --save-dev jest jest-cli puppeteer faker
Once the installation is done, create a file named
App.test.js and let’s begin to edit with the code block below.
const faker = require('faker'); const puppeteer = require('puppeteer'); const person = { email: faker.internet.email(), password: faker.random.word(), }; const appUrlBase = '' const routes = { public: { register: `${appUrlBase}/register`, login: `${appUrlBase}/login`, noMatch: `${appUrlBase}/ineedaview`, }, private: { home: `${appUrlBase}/home`, account: `${appUrlBase}/account`, }, };
Just like the tests written above,
faker and
puppeteer are imported. A
person object is created and it stores a random email and password that will be used for testing. The
appUrlBase constant is the link to the React app — if you haven’t started the React app, run
npm start in your terminal and change
appUrlBase to the link.
The
routes object contains the various URLs to the views we’ll be testing. The
public object contains links to routes in the React app that can viewed by anyone (not logged in), while the
private object contains links to routes that can only be viewed if you’re logged in.
Note that
noMatch is what will be used to test for nonexistent views/route returns a 404 page, that’s why it aptly leads to
/ineedaview.
Alright, let’s write the first test now.
Users can login
//create global variables to be used in the beforeAll function let browser let page beforeAll(async () => { // launch browser browser = await puppeteer.launch( { headless: false, // headless mode set to false so browser opens up with visual feedback slowMo: 250, // how slow actions should be } ) // creates a new page in the opened browser page = await browser.newPage() }) describe('Login', () => { test('users can login', async () => { await page.goto(routes.public.login); await page.waitForSelector('.signin-form'); await page.click('input[name=email]') await page.type('input[name=email]', 'yomi@mail.com') await page.click('input[name=password]') await page.type('input[name=password]', 'password') await page.click('button[type=submit]') await page.waitForSelector('[data-testid="homepage"]') }, 1600000); }); // This function occurs after the result of each tests, it closes the browser afterAll(() => { browser.close() })
The code block above is different from the first set of tests we wrote above. First, the
beforeAll function is used to launch a new browser with its options and create a new page in that browser as opposed to creating a new browser in every single test suite like we did in the tests earlier.
So how do we test here? In the test suite, the browser is directed to the login page which is
routes.public.login and just like the contact form test, puppeteer is used to fill the form and submit it. After submitting the form, puppeteer then waits for a selector
data-testid='homepage' which is a
data-id that is present on the Home page — the page the React app redirects to after a successful login.
I already created an account with the user details in the code block, therefore this test should pass.
The
afterAll function happens after the end of tests and it closes the browser.
Users can logout
This is the view that’s shown after a successful login. Now we want to test what happens when a user clicks on the sign out button. The expected outcome is the localStorage is cleared, logged out and the user is redirected back to the Sign In page.
In the same
App.test.js file, add the code below just before the
afterAll function.
describe('Logout', () => { test('users can logout', async () => { await page.waitForSelector('.nav-link'); await page.click('[data-testid="signoutBtn"]') await page.waitForSelector('.signin-form') }, 9000000); });
This test is fairly straightforward. puppeteer waits for the
.nav-link selector and it clicks on the button with a data attribute of
data-testid=”signoutBtn” and that is actually testing if the button can be clicked. After the
page.click() function, puppeteer waits for the selector
Congratulations, another test passed.
Users are redirected to the login page for unauthorized view
We don’t want users having access to views and routes that they are not authorized to view. So let’s test if the code does that.
Add the code block below to the existing code, just before the
afterAll function
describe('Unathorized view', () => { test('users that are not logged in are redirected to sign in page', async () => { await page.goto(routes.private.home); await page.waitForSelector('.signin-form') }, 9000000); });
In the code block above, we test by going to a private route in the React and then wait for the
This means after a user navigates to a private route, they are automatically redirected to the login form.
Nonexistent views/route returns a 404 page
It’s important for all apps to have a 404 page so as to explain to a user that that particular route doesn’t exist. It was implemented in this React app too, let’s test if it works as expected.
Add the code block below to the existing code, just before the
afterAll function.
describe('404 Page', () => { test('users are redirected to a 404 page for nonexistent views', async () => { await page.goto(routes.public.noMatch); await page.waitForSelector('.no-match') }, 9000000); });
The
routes.public.noMatch link we created earlier points to a route that doesn’t exist. Therefore when puppeteer goes to that link, it’s expecting that it automatically redirects to the 404 page. The
.no-match selector is located on the 404 page.
Conclusion. Puppeteer is still being actively developed so make sure to check the API reference for more features.
The codebase for this tutorial can be seen on GitHub here and here.
Resources
Jest:
Puppeteer: “End-to-end testing React apps with Puppeteer and Jest”
The CRA seems to have updated the App.js, the css selector is now .App-header and the content is not Welcome to React. It would be helpful if you can update the App.test.js. Thanks!
|
https://blog.logrocket.com/end-to-end-testing-react-apps-with-puppeteer-and-jest-ce2f414b4fd7/
|
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| 58.28
|
Timeline
Aug 22, 2007:
- 6:52 PM Changeset [6691] by
- Fixed indexing to fetch line from shape.
- 1:26 PM Ticket #2258 (wms GetFeatureInfo response displays a different scale on Windows than ...) created by
- The scale in the response to a GetFeatureInfo? is different as the one …
- 11:53 AM Ticket #2257 (WMS describelayer doesn't return the correct version on Windows) created by
- When I issue the following request on Windows with MapServer …
- 11:45 AM Changeset [6690] by
- Tagging source as rel-5-0-0-beta5
- 11:45 AM Changeset [6689] by
- Creating tags/rel-5-0-0-beta5
- 11:43 AM Changeset [6688] by
- Update for 5.0.0-beta5
- 11:38 AM Ticket #2256 (XSS vulnerabilities in mapserv CGI) closed by
- fixed: The attached patch (above) can be used to patch your MapServer 4.8 or …
- 11:31 AM Changeset [6687] by
- Fixed XSS vulnerabilities (#2256)
- 11:29 AM Changeset [6686] by
- Fixed XSS vulnerabilities (#2256)
- 11:28 AM Changeset [6685] by
- Fixed XSS vulnerabilities (#2256)
- 11:20 AM Milestone 4.10.3 release completed
-
- 11:13 AM Changeset [6684] by
- Tagging 4.10.3 source
- 11:12 AM Changeset [6683] by
- Creating tags/rel-4-10-3
- 11:09 AM Changeset [6682] by
- Update for 4.10.3
- 11:06 AM Changeset [6681] by
- Fixed XSS vulnerabilities (#2256)
- 11:01 AM Changeset [6680] by
- Removed unnucessary gsub() call in last changeset
- 10:55 AM Changeset [6679] by
- Fixed XSS vulnerabilities (#2256)
- 10:53 AM Ticket #2215 (HowTo Build AGG with freetype support from sources) closed by
- fixed: Thomas has committed r6677 that fixes a few typo in my r6676 changes …
- 10:22 AM Changeset [6678] by
- move ogr locking defines outside use_ogr ifdef
- 10:06 AM Changeset [6677] by
- typos in agg configure logic - changed error message when …
- 9:27 AM Changeset [6676] by
- configure --with-agg=DIR now automatically tries to build …
- 9:06 AM Changeset [6675] by
- AGG: clean up font rendering function.
- 8:09 AM Changeset [6674] by
- removed GetLegendGraphic? and GetStyles? as they are not output for 1.1.0 DTD
- 8:08 AM Changeset [6673] by
- Adding missing includes for the AGG builds
- 7:06 AM Changeset [6672] by
- New.
- 7:04 AM Changeset [6671] by
- New.
- 6:20 AM Ticket #2256 (XSS vulnerabilities in mapserv CGI) created by
- Chris Schmidt has reported a XSS vulnerability in the mapserv CGI and …
- 5:29 AM Ticket #2255 (C#(MapServer 5.0 Beta3) - Exceptions caused by imageObj.write() and ...) created by
- Hi there, I've compiled MapServer 5.0 Beta3 myself with VS2005, …
- 4:04 AM Changeset [6670] by
- Added the example for writing onto a FileStream?
Aug 21, 2007:
- 2:00 PM Ticket #2254 (Response to WMS getcapabilities request version 1.1.1 asks for a ...) created by
- When I issue a WMS getcapabilities request to MapServer 5.0.0-beta4 by …
- 1:52 PM Ticket #2253 (Response to a WMS getcapabilities version 1.1.0 request doesn't ...) created by
- I issue the following request to MapServer 5.0.0-beta4 through …
- 1:28 PM Ticket #2252 (Possible buffer overflow in template processing) closed by
- fixed: Fixed. Will be in 5.0-beta5 (r6669) and in 4.10.3 (r6668).
- 1:28 PM Changeset [6669] by
- Fixed possible buffer overflow in template processing (#2252)
- 1:26 PM Changeset [6668] by
- Fixed possible buffer overflow in template processing (#2252)
- 1:24 PM Changeset [6667] by
- Fixed old refs to libmap.a (now libmapserver.a) in PHP MapScript? build …
- 12:59 PM Ticket #2252 (Possible buffer overflow in template processing) created by
- There is a small possibility of buffer overflow in processLine() …
- 11:54 AM Changeset [6666] by
- Fix build problem on windows
- 9:55 AM Changeset [6665] by
- fix blending of transparent layers with RGBA images
- 7:29 AM Changeset [6664] by
- rename variable to something more sensible
- 7:20 AM Changeset [6663] by
- AGG: greatly speed up pixmap marker rendering
Aug 20, 2007:
- 9:05 PM Ticket #2220 (factory for creating map objects from mapfile strings and fragments) closed by
- fixed
- 9:50 AM Changeset [6662] by
- warning cleanup #2237
- 9:23 AM Changeset [6661] by
- don't use a zero-width contour for fonts
- 9:07 AM Ticket #2244 (WCS supportedFormats - need to split <formats> tag) closed by
- fixed: I wonder what I meant by the cryptic "fix the correct result" message? …
- 8:25 AM Changeset [6660] by
- modified due to change in r6050
- 8:13 AM Changeset [6659] by
- added empty ContactInformation? element and svg as a GetMap? format as …
- 7:20 AM Ticket #2226 (maptime.c warnings) closed by
- fixed: Fixed in r6658 using _GNU_SOURCE in maptime.c as described above. I …
- 7:17 AM Changeset [6658] by
- Fixed compile warnings
- 7:08 AM Changeset [6657] by
- Implement OGR thread-safety via use of an OGR lock. (#1977)
- 7:00 AM Changeset [6656] by
- Implement OGR thread-safety via use of an OGR lock. (#1977)
- 6:57 AM Ticket #2249 (Adding MS_CURRENT besides MS_BASE in the Windows builds) closed by
- fixed: Applied in the trunk
- 6:51 AM Ticket #2251 (mappdf.c compile warnings ... PDF support broken?) closed by
- fixed: Fixed in r6655. All warnings except the last one were related to …
- 6:50 AM Changeset [6655] by
- Fixed compile warnings
- 6:48 AM Ticket #2251 (mappdf.c compile warnings ... PDF support broken?) created by
- mappdf.c produces the following warnings: […] The warning from …
- 4:34 AM Changeset [6654] by
- Allow BINDIR to be specified externally
- 2:15 AM Changeset [6653] by
- agg: cleanup unused includes and left over gd functions
Aug 19, 2007:
- 8:51 PM Changeset [6652] by
- ArcSDE tests
- 8:50 PM Changeset [6651] by
- ArcSDE test results
- 7:29 PM Changeset [6650] by
- add a -valgrind option for running all of the tests (slowly) under …
- 5:09 PM Changeset [6649] by
- updated
- 2:51 PM Changeset [6648] by
- Adding MS_CURRENT besides MS_BASE in the Windows builds (#2249)
- 12:33 PM Changeset [6647] by
- Note about fixing #2250
- 12:21 PM Changeset [6646] by
- fix last fix (r6642)
- 10:49 AM Changeset [6645] by
- ignore Makefiles
- 9:23 AM Changeset [6644] by
- add expected output for ArcSDE tests
- 9:20 AM Ticket #2250 (Adding -DUSE_GENERIC_MS_NINT to the WIN64 builds) closed by
- fixed: Applied in trunk r6642
- 9:16 AM Changeset [6643] by
- fix last fix (r6605)
- 8:37 AM Changeset [6642] by
- Adding -DUSE_GENERIC_MS_NINT to the WIN64 builds (#2250)
- 5:39 AM Ticket #2247 (Labels not wrapping in AGG with WRAP in LABEL definition) closed by
- fixed: this was fixed just after beta3. please try with beta4.
Aug 18, 2007:
- 4:16 PM Ticket #2250 (Adding -DUSE_GENERIC_MS_NINT to the WIN64 builds) created by
- When compiling mapserver for the Win64 platform using the default …
- 3:00 PM Ticket #2249 (Adding MS_CURRENT besides MS_BASE in the Windows builds) created by
- In order to add the mapscript python build steps to the buildbot we …
Aug 17, 2007:
- 4:04 PM Ticket #2240 (Support to run the mapscript c# examples on x64 platform) closed by
- fixed: Committed to the SVN trunk
- 4:00 PM Ticket #2241 (Adding msSaveImageBuffer and use that from the mapscript library to ...) closed by
- fixed: Applied in the SVN trunk
- 3:56 PM Changeset [6641] by
- Adding msSaveImageBuffer and use that function from the mapscript …
- 3:54 PM Changeset [6640] by
- Adding msSaveImageBuffer and use that function from the mapscript …
- 2:34 PM Changeset [6639] by
- ensure formats are split into seperate elements (#2244)
- 2:32 PM Changeset [6638] by
- formats now split into multiple elements (#2244)
- 2:30 PM Changeset [6637] by
- ensure formats are split into seperate elements (#2244)
- 2:26 PM Ticket #2248 (GetObservation SWE DataBlock support) created by
- > Can you expand on the swecommon response a bit more? Is this the > …
- 2:12 PM Ticket #1088 (GetMap Width/Height/Format are required parameters) closed by
- fixed: Thanks Norm! So the msautotest/wxs which were affected by this ticket …
- 1:35 PM Ticket #2247 (Labels not wrapping in AGG with WRAP in LABEL definition) created by
- When using DRIVER AGG/PNG in OUTPUTFORMAT and WRAP ' ' in LABEL, the …
- 1:32 PM Ticket #2246 (upgrade SOS to 1.0.0) created by
- SOS is currently v 0.1.2. (Correct me if I'm wrong, please.) Are …
- 1:32 PM Changeset [6636] by
- Make sure truncate_on_decimal supports long numbers.
- 1:26 PM Ticket #2245 (Wrapping of labels by width/# characters) created by
- It would be useful to have the ability to specify that labels be …
- 1:02 PM Changeset [6635] by
- Added width, height, format, srs and style in the getmap request …
- 1:02 PM Changeset [6634] by
- Ajusted aspect ratio following addition of width, height, format, srs …
- 1:01 PM Changeset [6633] by
- Added width, height, format, srs and style in the getmap request …
- 12:59 PM Changeset [6632] by
- Ajusted aspect ratio following addition of width, height, format, srs …
- 12:54 PM Changeset [6631] by
- Added C# sample for imageObj.getBytes (#2241)
- 12:50 PM Changeset [6630] by
- Added width, height, format, srs and style in the getmap request …
- 12:50 PM Changeset [6629] by
- Ajusted aspect ratio following addition of width, height, format, srs …
- 12:47 PM Changeset [6628] by
- Added width, height, format, srs and style in the getmap request …
- 12:44 PM Changeset [6627] by
- Ajusted aspect ratio following addition of width, height, format, srs …
- 12:17 PM Changeset [6626] by
- Visually identical. Updated.
- 12:11 PM Changeset [6625] by
- Adjusted extents and image size in the getmap request to keep the …
- 12:09 PM Changeset [6624] by
- Added width, height, format, srs and style in the getmap request …
- 12:07 PM Changeset [6623] by
- Ajusted aspect ratio following addition of width, height, format, srs …
- 11:22 AM Changeset [6622] by
- Fix last patch (restore removed lines).
- 11:04 AM Changeset [6621] by
- Removed outdated Log messages.
- 10:57 AM Changeset [6620] by
- Support to run the mapscript c# examples on x64 platform (#2240)
- 10:56 AM Changeset [6619] by
- Support to run the mapscript c# examples on x64 platform (#2240)
- 9:48 AM Ticket #2244 (WCS supportedFormats - need to split <formats> tag) created by
- WCS 1.0 should have a seperate <formats> tag for each format …
- 9:17 AM Ticket #2243 (Icons are not generated for HTML legends) closed by
- fixed: Fixed in r6618. The problem had been introduced in r6583... the test …
- 9:15 AM Changeset [6618] by
- Fixed processIcon() which was producing enpty legend icons due to a …
- 8:48 AM Ticket #2242 ([WMS Client] set styles parameter when sending remote WMS GetMap requests) closed by
- fixed: Looking at mapwmslayer.c (line 308 ish), the code already did most …
- 8:46 AM Changeset [6617] by
-
- 8:43 AM Changeset [6616] by
- set STYLES no matter what, even if it's empty (i.e. "STYLES=") …
- 8:32 AM Ticket #2243 (Icons are not generated for HTML legends) created by
- I have found a bug with HTML legends in MapServer 5 beta 4. The icons …
- 8:25 AM Ticket #2242 ([WMS Client] set styles parameter when sending remote WMS GetMap requests) created by
- As a result of #1088, STYLES is a required parameter in MapServer WMS …
- 7:48 AM Ticket #2241 (Adding msSaveImageBuffer and use that from the mapscript library to ...) created by
- So as to keep the renderer specific msSaveImageBufferGD and …
- 7:06 AM Ticket #2239 (Support for encoding in legend and SVG output) closed by
- fixed: Fixed with a final patch to fix the retrun value of msDrawLegend() in …
- 7:00 AM Changeset [6615] by
- Fixed problem with return value introduced with last change (#2239)
- 6:57 AM Ticket #2083 (Load/update map objects from config strings) closed by
- fixed: ok. This bug just seemed like more of a political statement with no …
- 6:22 AM Changeset [6614] by
- Fixed support for label encoding in SVG output (#2239)
- 6:04 AM Ticket #2240 (Support to run the mapscript c# examples on x64 platform) created by
- When compiling mapscript with VS2005 the default setting does not …
- 6:02 AM Changeset [6613] by
- Support for label encoding in legend (#2239)
- 5:47 AM Ticket #2239 (Support for encoding in legend and SVG output) created by
- […]
- 4:52 AM Ticket #42 (Memory leaks) closed by
- fixed: I think it's safe to close this one. We've been doing lots of leak …
- 4:46 AM Changeset [6612] by
- Added GEOS in the list of needed dependencies.
- 12:17 AM Ticket #2083 (Load/update map objects from config strings) reopened by
-
- 12:17 AM Ticket #2083 (Load/update map objects from config strings) closed by
- invalid: This work is done for 5.0, correct?
- 12:12 AM Ticket #2229 (msFreeHashItems should not set an error for a table with no items) closed by
- fixed
Aug 16, 2007:
- 11:46 PM Ticket #1907 (More useful msSetError message clobbered by less useful msSetError message) closed by
- fixed: Closing. Re-open if this is still a problem. RFC 18 also addresses a …
- 11:45 PM Ticket #1906 (segmentation violation when layer item indexes are used and initValues ...) closed by
- fixed: Looks like this can be closed. Re-open if necessary…
- 11:40 PM Ticket #1831 (MapServer doesn't flex or bison on Windows) closed by
- fixed: These files are now kept in SVN by default.
- 11:23 PM Ticket #1404 (error compilation mapserver) closed by
- worksforme: Closing for lack of follow up.
- 11:19 PM Ticket #1038 (FCGI on Windows does not kill mapserv processes) closed by
- worksforme: Brock, Please re-open this if it is still an issue. The SDE driver …
- 11:15 PM Ticket #563 (Show Big-5 with new version of GD) closed by
- fixed: I think this topic is well covered now and this bug can be closed. …
- 3:32 PM Ticket #2207 (msGeometry Property does not substitute the group ...) closed by
- invalid: To verify, comment:2 outlines the examples in the GML 2.1.2 …
- 1:13 PM Changeset [6611] by
- New result, visually identical.
- 1:10 PM Changeset [6610] by
- New result, visually identical.
- 12:42 PM Changeset [6609] by
- gml_include_items was not set. This is why no result was found.
- 12:40 PM Changeset [6608] by
- Small decimal changes in the feature coordinates.
- 11:34 AM Changeset [6607] by
- cast to const for second argument of iconv in msConvertWideStringToUTF8
- 11:33 AM Changeset [6606] by
- use appropriate cast for iconv function in msConvertWideStringToUTF8
- 11:32 AM Changeset [6605] by
- don't leak so much
- 10:57 AM Changeset [6604] by
- use msConvertWideStringToUTF8 for unicode conversion for SDE
- 9:39 AM Changeset [6603] by
- comment out msConvertWideStringToUTF8 for now
- 9:33 AM Changeset [6602] by
- add msConvertWideStringToUTF8 for wide character conversion
- 8:43 AM Ticket #2233 (Polygon outline thickness keeps growing and growing...) closed by
- fixed: Scale factors are can be something other than 1 when SYMBOLSCALE is …
- 8:35 AM Ticket #1892 (Use getExpressionString/getFilterString/getTextString in PHP MapScript) closed by
- fixed: Fixed in r6601: Added class.getTextString() and deprecated/renamed …
- 8:34 AM Changeset [6601] by
- Added class.getTextString() and deprecated/renamed …
- 7:55 AM Ticket #2238 (incorrect qouting of generated mapfile) created by
- When a mapfile is generated from a mapobject (using the python …
- 7:49 AM Ticket #480 ([MapScript] QueryByAttributes() requires qitem arg even if unused) closed by
- fixed: Steve had fixed msQueryByAttributes() to accept qitem=NULL, but …
- 7:48 AM Changeset [6600] by
- Treat empty qitem arg the same way as NULL in msQueryByAttributes() (#480)
- 6:54 AM Ticket #900 ([PHP MapScript] Add layer.getFeature()) closed by
- fixed: layer.getFeature(int shapeindex [, int tileindex = -1]) added to PHP …
- 6:53 AM Changeset [6599] by
- Added layer.getFeature() in PHP MapScript? with optional tileindex arg, …
- 6:11 AM Ticket #1007 (WMS GetLegendGraphic and out of scale layers (or empty legends)) closed by
- fixed: I did a few more tests with the current 5.0 code in SVN, and …
- 5:56 AM Ticket #1009 (WMS GetLegendGraphic should honour class->scale) closed by
- fixed: Sounds like support of class minscale/maxscale would have been fixed …
- 5:40 AM Changeset [6598] by
- don't scale outline width for polygon and circle layers (bug 2233)
- 5:22 AM Changeset [6597] by
- history
- 5:11 AM Ticket #2235 ([AGG] PIXMAP symbols render incorrectly on PPC builds) closed by
- fixed: fixed in r6596
- 5:10 AM Changeset [6596] by
- AGG: fix pixmap rendering on MSB architectures
Aug 15, 2007:
- 11:15 PM Ticket #2067 (CLASSITEMs are no longer case insensitive) closed by
- fixed: Haven't found any problems. We can reopen if something shows up.
- 8:07 PM Ticket #2237 (msGetEncodedString does not work with wide strings) created by
- I have been unable to get msGetEncodedString to work when for drawing …
- 7:54 PM Ticket #2236 (mapserver 4.10.2 does not render tiled shapefile data layers with ...) created by
- Up until mapserver 4.8.4, we have been able to render multiple …
- 2:03 PM Ticket #2235 ([AGG] PIXMAP symbols render incorrectly on PPC builds) created by
- When rendering symbols of type PIXMAP with the AGG renderer, the …
- 1:29 PM Ticket #2234 (Test MapServer against OGC WMS 1.1.1 compliance test engine) created by
- Normand, this ticket is to track testing of MapServer's WMS 1.1.1 …
- 12:50 PM Ticket #2233 (Polygon outline thickness keeps growing and growing...) created by
- Polygon outlines, e.g. […] should always be 1 pixel but with AGG …
- 11:26 AM Changeset [6595] by
- Tag source as rel-5-0-0-beta4
- 11:25 AM Changeset [6594] by
- Creating tags/rel-5-0-0-beta4/
- 11:24 AM Changeset [6593] by
- Updated for 5.0.0-beta4
- 9:16 AM Ticket #2224 (Compile error on 5.0beta3 with AGG) closed by
- wontfix: I don't think I'll fix this as this seems to be a compiler bug. …
- 8:41 AM Ticket #2231 (AGG:) closed by
- fixed: I added a test to make sure the format is RGB or RGBA, throws an error …
- 8:40 AM Changeset [6592] by
- Updated msImageCreateGD to only allow RGB or RGBA pixel models. (bug 2231)
- 8:17 AM Ticket #1962 (setimagepath problem) closed by
- fixed: I have verified that Howard's fix in r6565 solves the issue for PHP as …
- 8:17 AM Changeset [6591] by
- Fixed problem with symbol.setImagePath() when file doesn't exist …
- 8:16 AM Changeset [6590] by
- Added an AGG specific error code.
- 7:37 AM Ticket #1164 (Enhancement of the symbolObj class in php mapscript to handle pixmaps ...) closed by
- fixed: This was fixed in v4.8 with the implementation of …
- 7:36 AM Ticket #1367 (symbolObj fixes for PHP Mapscript 4.6.0-beta2) closed by
- fixed: This was fixed in v4.8 with the implementation of …
- 7:21 AM Changeset [6589] by
- Added note about #2218 (same issue as #2228)
- 7:20 AM Ticket #2218 (Segmentation fault with some of the Chameleon samples (Chameleon ...) closed by
- fixed: The problem was that all those samples had legends with layers with no …
Aug 14, 2007:
- 10:20 PM Changeset [6588] by
-
- 9:41 PM Ticket #2021 (INCLUDE is only parsed in the first mapfile) closed by
- fixed: Marking as fixed for 5.0. Any reason to backport to 4.10? If so, we …
- 9:38 PM Changeset [6587] by
- Changed lexer initalization for file and string parsing to set the …
- 9:06 PM Ticket #2227 (AGG:incorrect lookup of symbol in symbolset) closed by
- fixed: Closing…
- 9:04 PM Changeset [6586] by
- Fixed a bounds check for symbol indexes in the GD code that sneeked …
- 8:51 PM Ticket #2089 (Per-Mapscript reporting too many open files) closed by
- fixed: Marking as fixed... (if we issue another 4.10 release I will backport) …
- 8:30 PM Changeset [6585] by
- no need to free the layer now that we are dynamic
- 3:41 PM Ticket #2232 ("minfeaturesize auto" causes labels to never be drawn) created by
- Issue: "minfeaturesize auto" is documented as causing labels to appear …
- 2:42 PM Ticket #2231 (AGG:) created by
- A mapfile where the IMAGEMODE "PC256" using the AGG driver causes a …
- 2:26 PM Ticket #2230 (Beta-3 python script test failed) created by
- ...................................F................................... …
- 2:08 PM Ticket #966 (GetLegendGraphic output not aligned) closed by
- fixed: Fixed in r6584. We simply had to override the legend->label.position …
- 2:06 PM Changeset [6584] by
- Fixed alignment of GetLegendGraphic? output when mapfile contains no …
- 1:19 PM Ticket #2228 (Seg Fault with HMTL legend in processIcon) closed by
- fixed: Fixed in r6583 (will be in 5.0.0-beta4). The HTML legend generation …
- 1:17 PM Changeset [6583] by
- Fixed seg. fault when generaing HTML legend for raster layers with no …
- 9:20 AM Changeset [6582] by
- typo
- 8:30 AM Ticket #2229 (msFreeHashItems should not set an error for a table with no items) created by
- msFreeHashItems is setting an error that eventually gets thrown as a …
- 8:07 AM Ticket #1903 ([WFS-Server] DescribeFeatureType output with ows_metadataurl_type) closed by
- fixed: Replying to sdlime: > I think the docs are up-to-date, …
- 7:55 AM Changeset [6581] by
- Fixed warning about msyylex_destroy() in maputil.c.
- 7:53 AM Changeset [6580] by
- Cleaned up one comment in mapgml.c.
- 7:36 AM Changeset [6579] by
- Restrict GML transformation to the gml_ metadata prefix to avoid …
- 7:32 AM Ticket #2228 (Seg Fault with HMTL legend in processIcon) created by
- In ticket #1946, jparapar wrote: > > We have compiled beta 3 and …
- 1:52 AM Ticket #2227 (AGG:incorrect lookup of symbol in symbolset) reopened by
- When I have "SYMBOL 1" I still get a core dump in mapagg.cpp line 1418 …
Aug 13, 2007:
- 3:38 PM Changeset [6578] by
- added former username when CVS was used
- 2:14 PM MapServerAsWMS edited by
- (diff)
- 1:53 PM Changeset [6577] by
- added ContactInformation? and svg as GetMap? format
- 1:52 PM Changeset [6576] by
- added stroke-opacity as default
- 1:50 PM MapServerAsWMS edited by
- (diff)
- 1:50 PM Changeset [6575] by
- updated GetMap? params, which are now required
- 1:49 PM Changeset [6574] by
- changed to 1.1.1 as default
- 1:46 PM MapServerAsWMS created by
-
- 1:28 PM Changeset [6573] by
- changed as a result of changes in #1088
- 12:00 PM Changeset [6572] by
-
- 11:19 AM Changeset [6571] by
- don't do a case sensitive search in string2list (#2067)
- 11:04 AM Changeset [6570] by
- commit an extra large layer->items to prevent string2list in …
- 10:42 AM Ticket #1637 (SLD WMS GetStyles: bug translating regex to PropertyIsLike) closed by
- fixed
- 10:28 AM Ticket #2227 (AGG:incorrect lookup of symbol in symbolset) closed by
- fixed: fixed in r6569 thanks
- 10:26 AM Changeset [6569] by
- bail out if symbol is invalid (closes #2227)
- 9:01 AM Changeset [6568] by
- ensure operator precedence
- 8:04 AM Ticket #2227 (AGG:incorrect lookup of symbol in symbolset) created by
- when using dynamic symbols there is a lookup in the symbolset but the …
- 6:04 AM Ticket #131 (WMS interface does not support "dimensions" (additional parameters)) closed by
- wontfix: Since there hasn't been much traffic on this issue, and that the same …
- 1:20 AM Changeset [6567] by
- use msDrawTextGD instead of msDrawLabel (prevents switching from GD to …
Aug 12, 2007:
- 9:07 AM Changeset [6566] by
- test case for #1962
- 9:00 AM Changeset [6565] by
- return the filename in the error for msLoadImageSymbol #1962
- 8:25 AM Ticket #1119 (WMS client makes non-square pixel request when cascading) closed by
- invalid: Reading through, it looks like this bug is invalid because ArcIMS is …
Aug 11, 2007:
- 8:14 PM Ticket #2135 (projection error) closed by
- duplicate: Ed, This bug is duplicate of #2107 and is fixed for the upcoming 5.0 …
- 8:05 PM Changeset [6564] by
- support writing AGG formats with Python MapScript?'s write() method
- 7:53 PM Changeset [6563] by
- add support for setuptools' 'develop' target. All other build …
- 7:44 PM Changeset [6562] by
- more notes
- 7:43 PM Changeset [6561] by
- propset
- 7:41 PM Changeset [6560] by
- notes about using swig 1.3.31's optimization options
- 7:14 PM Changeset [6559] by
- STYLES now required in WMS requests (#1088)
- 7:05 PM Changeset [6558] by
- roll back 6557. iconv seems to have changed its signature from …
- 5:57 PM Ticket #912 (Windows build warnings in mapgd.c and others) closed by
- fixed: I'm only seeing one warning in maptime.c which I filed as a separate …
- 5:55 PM Ticket #2226 (maptime.c warnings) created by
- […] The code does this: […] I'm compiling on linux FC4 here, …
- 5:34 PM Changeset [6557] by
- we still need to cast &inp to char for the iconv function in …
- 5:26 PM Ticket #2072 (getFeatureInfo error with ArcSDE layers) closed by
- invalid: I imported the SDE export file you sent me. None of the columns in …
- 11:44 AM Changeset [6556] by
-
- 11:42 AM Ticket #2225 (Support Unicode for ArcSDE 9.2 and above) closed by
- fixed
- 11:39 AM Changeset [6555] by
- unicode attributes support #2225
- 11:39 AM Ticket #2225 (Support Unicode for ArcSDE 9.2 and above) created by
- ArcSDE 9.2 adds support for unicode data attributes. We can use …
- 2:18 AM Changeset [6554] by
- free AGG image structure even when img.gd is NULL (caused memory leak …
Aug 10, 2007:
- 12:52 PM Ticket #2224 (Compile error on 5.0beta3 with AGG) created by
- I'm trying to compile Mapserver 5.0 beta3 with AGG support under …
- 7:33 AM Changeset [6553] by
- avoid using gd functions to compute glyph size
- 7:29 AM Ticket #2223 (ANGLE FOLLOW for labels doesn't handle short strings properly) created by
- I have noticed that using ANGLE FOLLOW for labels along lines when the …
- 6:13 AM Changeset [6552] by
- msWMSDescribeLayer: replace hardcoded version on XML output with …
- 6:08 AM Changeset [6551] by
- modify msWMSLoadGetMapParams to not be as strict for DescribeLayer? …
- 5:09 AM Changeset [6550] by
- added info on #1088
- 5:00 AM Changeset [6549] by
- msWMSLoadGetMapParams: fixed handling of required parameters (#1088) …
- 4:55 AM Changeset [6548] by
- updated with correct function names to display during some …
- 3:35 AM Ticket #2191 (AGG missing a few symbol options that GD has) closed by
- fixed: closing for now as AGG should now support all symbology - please …
- 2:57 AM Changeset [6547] by
- update history, move unneeded angle computation out of loop
- 2:50 AM Changeset [6546] by
- correctly treat the symbol GAP parameter (follows line angle only if …
- 2:37 AM Changeset [6545] by
- don't treat truetype symbol POSITION if set to follow line
- 1:40 AM Changeset [6544] by
- leverage font cache when rendering labelcache
- 1:12 AM Changeset [6543] by
- treat newlines in labels better centering for truetype marker symbols
Aug 9, 2007:
- 6:02 PM Ticket #2222 (shp2img should support setting output size) created by
- add a -s sizex sizey image to shp2img to set the image output size
- 5:48 PM Ticket #2221 (Bad 'angle follow' case -- possibly a use for splining) created by
- Uses: …
- 12:36 PM Ticket #1857 (SLD label implementation is non-conformant to OGC SLD spec) closed by
- fixed: Tom, I guess it would be for the user to validate the SLD (or should …
- 12:27 PM Changeset [6542] by
- Pass templatepattern directly into loadClass instead of using map as a …
- 12:06 PM Ticket #1998 ([SLD] Error messages in SLD) closed by
- fixed
- 11:44 AM Changeset [6541] by
- Add mapscript.fromstring for rfc-31 (#2220)
- 11:43 AM Ticket #2220 (factory for creating map objects from mapfile strings and fragments) created by
- Part of. I'm …
- 11:34 AM Ticket #2219 (msUpdateClassFromString segfaults when class is not in a layer) created by
- Since version 4.4 (maybe even earlier), we've been allowing users to …
- 10:26 AM Changeset [6540] by
- fix truetype symbol position on lines
- 10:13 AM Changeset [6539] by
- check for OGR support in if SLD is used (#1998)
- 9:43 AM Changeset [6538] by
- check for OGR support in if SLD is used (#1998)
- 8:43 AM Ticket #1876 ([WMS-Client-Howto] Do not use EPSG:42304 in examples) closed by
- fixed: I've made these changes to …
- 8:29 AM Changeset [6537] by
- truetype symbols must follow line orientation if gap is 0
- 8:13 AM Changeset [6536] by
- Added truetype symbolization for lines and polygons Draw an outline of …
- 8:01 AM Ticket #2218 (Segmentation fault with some of the Chameleon samples (Chameleon ...) created by
- I reproduced the problem originally reported by Mike Leahy where some …
- 7:18 AM Ticket #2206 (Update configure script for new msDebug() behavior) closed by
- fixed: Fixed in r6535. The -DENABLE_STDERR_DEBUG and msDebug-related …
- 7:16 AM Changeset [6535] by
- Removed -DENABLE_STDERR_DEBUG and msDebug-related wstuff from …
- 6:41 AM Ticket #1966 (summarize options at end of configure) closed by
- fixed: Thanks for that Howard. Looks great! I have added a MapScript? section …
- 6:39 AM Changeset [6534] by
- Added PHP MapScript? to summary of config options (#1966)
- 12:38 AM Changeset [6533] by
- for lines use WIDTH for line width, except when symbol is ELLIPSE …
Aug 8, 2007:
- 10:18 PM Changeset [6532] by
- configure summary #1966
- 9:39 PM Changeset [6531] by
- more details on where to find info
- 9:34 PM Changeset [6530] by
- minor tweaks for #2186
- 9:32 PM Changeset [6529] by
- The dreaded off-by-one error again was leading to scale computation …
- 9:27 PM Ticket #1865 (python test do not pass --without-wms) closed by
- fixed: All of the python mapscript tests are now passing for me except for …
- 9:07 PM Ticket #1896 (Detect GEOS 2.2.2+ in configure) closed by
- fixed
- 9:01 PM Changeset [6528] by
- Updated configure script to detect and require GEOS 2.2.2+ (#1896)
- 7:56 PM Ticket #2217 (Rename --enable-coverage to --enable-gcov) closed by
- fixed: Fixed. --enable-coverage has been renamed --enable-gcov in r6527 and …
- 7:54 PM Changeset [6527] by
- Renamed --enable-coverage configure option to --enable-gcov to avoid …
- 7:48 PM Ticket #2217 (Rename --enable-coverage to --enable-gcov) created by
- The name -f the --enable-coverage configure option is confusing and it …
- 7:44 PM Ticket #2216 (undefined symbol __gcov_merge_add with php_mapscript.so built with ...) closed by
- fixed: Fixed in r6526. The configure script adds "-fprofile-arcs …
- 7:43 PM Changeset [6526] by
- Fixed --enable-coverage option to work with php_mapscript.so (#2216)
- 6:53 PM Ticket #2216 (undefined symbol __gcov_merge_add with php_mapscript.so built with ...) created by
- If MapServer is configured with the --enable-coverage configure option …
- 2:03 PM Changeset [6525] by
- Correct variable initialization bug in function …
- 1:54 PM Changeset [6524] by
- Fixed ReST formatting after update of online copy
- 1:50 PM Changeset [6523] by
- use initValues (#2016)
- 1:43 PM Changeset [6522] by
- setPattern now instead of setStyle
- 1:39 PM Changeset [6521] by
- minscaledenom
- 1:38 PM Changeset [6520] by
- scaledenom
- 1:37 PM Changeset [6519] by
- {min,max}scaledenom now
- 1:35 PM Changeset [6518] by
- we now have 5 symbols it seems
- 1:34 PM Changeset [6517] by
- delete lint
- 1:32 PM Changeset [6516] by
- minscaledemon instead of minscale now
- 1:27 PM Changeset [6515] by
- testInsertTooManyStyles can go away now because of RFC 17
- 12:33 PM Changeset [6514] by
- Tagging source as rel-5-0-0-beta3
- 12:32 PM Changeset [6513] by
- Creating tags/rel-5-0-0-beta3
- 12:25 PM Changeset [6512] by
- Updated for 5.0.0-beta3
- 12:12 PM Ticket #2215 (HowTo Build AGG with freetype support from sources) created by
- Boy was it a pain to get agg to compile with freetype support. For the …
- 11:28 AM Changeset [6511] by
- AGG : test if size value is valid when draiwng lines with an ellipse …
- 11:23 AM Ticket #1312 (use of static string in msTmpFile()) closed by
- fixed: Closing again. Please create new ticket with more specific details if …
- 11:19 AM Ticket #977 (Setting map->transparent through mapscript has no effect) closed by
- fixed: The members of outputFormatObj are already settable in the current …
- 10:56 AM Ticket #2213 (msIO_printf() silently does nothing when output is larger than workbuf) closed by
- fixed: Closing this ticket as fixed since the original issue was that …
- 10:54 AM Changeset [6510] by
- #ifdef AGG around msSaveImageBufferAGG
- 10:54 AM Ticket #2214 (Get rid of fixed output buffer size in msIO_printf() and family) created by
- msIO_printf(), msIO_fprintf() and msIO_vfprintf() all have a fixed …
- 10:47 AM Changeset [6509] by
- temporary fix for AGG scalebar rendering
- 10:47 AM Changeset [6508] by
- make sure to import sysconfig
- 10:39 AM Changeset [6507] by
- Raise a msSetError() instead of silently returning -1 when output is …
- 10:18 AM Changeset [6506] by
- Updated MIGRATION_GUIDE.TXT relative to URL configuraton changes for …
- 8:22 AM Ticket #1946 (MapServer crashes in legend mode when works with long templates) closed by
- fixed: Fixed in r1946, using msIO_fwrite() instead of msIO_fprintf() to dump …
- 8:18 AM Changeset [6505] by
- use agg for legend rendering
- 8:04 AM Changeset [6504] by
- Fixed problems with very large HTML legends producing no output, use …
- 7:35 AM Ticket #2193 (Scale computation has changed from 4.10 to 5.0) closed by
- duplicate: Duplicate of #2166…
- 7:23 AM Ticket #2105 (Upgrade Filter encoding to use geos operators) closed by
- fixed: Added missing operators in doc. Closing.
- 7:13 AM Ticket #2213 (msIO_printf() silently does nothing when output is larger than workbuf) created by
- While looking into ticket #1946, I found that msIO_printf() does not …
- 6:54 AM Changeset [6503] by
- do not use setuptools for building Python MapScript?
- 6:51 AM Changeset [6502] by
- Add notes for bugs 2105 and 2096
- 6:18 AM Ticket #287 (msPOSTGISLayerGetExtent returns infinite extents) closed by
- wontfix: Closing as wontfix due to lack of activity. If this is still a current …
- 4:46 AM Ticket #2139 ([SLD] Support of Graphic Stroke for a Linesymbolizer) closed by
- fixed
- 3:22 AM Changeset [6501] by
- add support for label encoding in font rendering, and symbols of type …
- 12:35 AM Ticket #2204 (gpc_polygon_clip is bad configure test function for agg, sometimes missing) closed by
- fixed: I removed the test... Configure blindly assumes that libagg is there, …
- 12:35 AM Changeset [6500] by
- Removed configure check for agg that was problematic in some cases. …
Aug 7, 2007:
- 11:41 PM Ticket #1398 ([MapServer] SIZEITEM on POINT file causes crash) closed by
- fixed: Closing this one…
- 11:33 PM Ticket #2149 (query shapefile with underscore returns 0 results) closed by
- fixed: The core bug is fixed though... so marking as such. Steve
- 11:29 PM Ticket #1380 (MapServer WFS should not output LineString with a single coordinate) closed by
- wontfix: I checked and there is no check for degenerate features of any type …
- 11:23 PM Ticket #1316 (Error in writing style->width in writeStyle()) closed by
- fixed: Apparently fixed long ago... Steve
- 11:17 PM Changeset [6499] by
- Noticed that QUERYMAPs used the STYLE keyword too. Enabled using TYPE …
- 11:10 PM Ticket #2130 (tileindex : possiblity of memeory leak) closed by
- fixed: Assuming Assefa's patch resolved this one. Closing. Steve
- 11:02 PM Ticket #2143 (Ticket to track RFC 31 developments) closed by
- fixed: Calling this complete. Other bugs may crop up but will manifest …
- 10:53 PM Ticket #583 (Highlight features behavior change suggestion) closed by
- wontfix: Marking as won't fix as we'll tackle QUERYMAPs in a future release and …
- 10:49 PM Ticket #2211 (Should we allow setting TEMPLATE via URL?) closed by
- fixed: The fix is a bit more complex. Basically we need to know what the …
- 10:37 PM Changeset [6498] by
- Enabled setting of templates (FOOTER, HEADER, TEMPLATE) and layer DATA …
- 4:24 PM Ticket #1466 (Adding support for WKT strings to MapServer...) closed by
- fixed: You are correct sir…
- 3:22 PM Changeset [6497] by
-
- 3:15 PM Changeset [6496] by
- use OGR destructors instead of delete for objects that have them …
- 2:52 PM Ticket #1867 (dylib checks missing for many libs in configure) closed by
- fixed
- 2:52 PM Changeset [6495] by
- doc update for #1867
- 2:44 PM Ticket #1776 (internal server error on GetMap request) closed by
- fixed
- 2:28 PM Ticket #2209 (Remove md5c.c and md5c.h?) closed by
- fixed: Done. md5c.c and md5.h removed in r6494.
- 2:28 PM Changeset [6494] by
- Removed unused md5c/c and md5.h source files (#2209)
- 2:09 PM Ticket #2212 (Need a msUTF8ToUniChar()) closed by
- fixed: Fixed. Added msUTF8ToUniChar() (maptclutf.c) in r6493 I went back to …
- 2:09 PM Changeset [6493] by
- Added msUTF8ToUniChar() based on Tcl_UtfToUniChar() from Tcl/Tk? …
- 1:30 PM Ticket #2212 (Need a msUTF8ToUniChar()) created by
- The mapagg.cpp rendering implementation needs a function to convert …
- 1:25 PM Changeset [6492] by
- Make MS_COLOR_GETRGB() return -1 if color not set/valid (#745)
- 1:19 PM Ticket #745 (HTML legend ignores map_layer_class_* changes) closed by
- fixed: Fixed in r6491. It was not possible to serialize the whole styleObj …
- 1:17 PM Changeset [6491] by
- Include style-related info in HTML legend icon filenames to solve …
- 1:10 PM Ticket #2211 (Should we allow setting TEMPLATE via URL?) created by
- With the new msUpdateMapFromURL(), we don't seem to be able to set the …
- 1:05 PM Changeset [6490] by
- fix name to be aggfontfreetype not aggfreetype
- 12:33 PM Ticket #2210 (msFreeHashItems() leaks table->items on empty hash tables) closed by
- fixed: Yup. Leak is gone. Thanks. Marking fixed.
- 12:29 PM Changeset [6489] by
- Removed check on numitems when free'ing a hash. (bug 2210)
- 12:23 PM Ticket #2210 (msFreeHashItems() leaks table->items on empty hash tables) created by
- msFreeHashItems() does not attempt to free the table->items memory if …
- 11:13 AM Changeset [6488] by
-
- 10:47 AM Ticket #2209 (Remove md5c.c and md5c.h?) created by
- Assefa, it seems that md5c.c and md5c.h are no longer used (they were …
- 8:17 AM Changeset [6487] by
- link against libaggfreetype
- 7:19 AM Ticket #2208 (mapscript java makefile dependency problem) created by
- In mapserver/mapscript/java/Makefile.in: […] In case parallel …
- 7:08 AM Ticket #2190 (mappostgis.c:msPOSTGISLayerRetrievePK() is malloc'ing improperly) closed by
- duplicate: Duplicate of #2140
- 6:02 AM Ticket #2207 (msGeometry Property does not substitute the group ...) created by
- Following the GML specification in version 2.1.2, each geometry …
- 4:31 AM Changeset [6486] by
- font rendering fixes. should now support outlines and shadows, and …
- 2:51 AM Changeset [6485] by
- Added text of rfc 24
Aug 6, 2007:
- 1:29 PM Ticket #2122 (WMS GetCapabilities w/Nested Groups seg fault) closed by
- fixed: Fixed in r6483 with a modified veersion of the patch. I did more …
- 1:15 PM Ticket #2206 (Update configure script for new msDebug() behavior) created by
- We need to udpate the configure script to remove -DENABLE_STDERR_DEBUG …
- 1:06 PM Changeset [6484] by
- some updates to use smoke.hobu.net
- 1:00 PM Changeset [6483] by
- Fixed issues with wms_layer_group metadata in WMS GetCapabilities? (#2122)
- 11:49 AM Changeset [6482] by
- prettyfy font rendering - outlining and shadows still not what they …
- 11:16 AM Changeset [6481] by
- Try to avoid warnings in old tiff card.
- 10:59 AM Changeset [6480] by
- added idfdefs around agg functions
- 10:29 AM Ticket #1662 (Memory-Leaks with TomCat/Oracle/Connection-Pool) closed by
- fixed: I believe we can mark this fixed now?
- 9:18 AM Ticket #2202 (Infinite loop in msStringConcatenate from msGetErrorString) closed by
- fixed: This was caused by the heap corruption of #2205
- 8:39 AM Changeset [6479] by
- include agg/font_freetype dir in include path
- 8:30 AM Changeset [6478] by
-
- 8:19 AM Ticket #2140 (Mapscript 4.10.0 and 4.10.2 gives segfault with Postgres 8) closed by
- fixed: I thought I had already committed it.
- 8:18 AM Changeset [6477] by
- Fix for #2140
- 7:58 AM Changeset [6476] by
- mapagg.cpp rewrite to avoid switching to/from gd rendering
- 7:57 AM Ticket #2140 (Mapscript 4.10.0 and 4.10.2 gives segfault with Postgres 8) reopened by
- Has this been applied the the 4.10 branch and HEAD?
Aug 5, 2007:
- 11:48 PM Ticket #2140 (Mapscript 4.10.0 and 4.10.2 gives segfault with Postgres 8) closed by
- fixed
- 11:03 PM Changeset [6475] by
- updated
- 11:02 PM Changeset [6474] by
- Added logic to add freetype include to AGG_INC - agg now depends on …
- 9:42 PM Changeset [6473] by
- Removed unused function.
- 8:31 PM Changeset [6472] by
- comment out unused kernel_size in msPolylineLabelPath
- 8:25 PM Changeset [6471] by
- remove unused variable
- 8:25 PM Changeset [6470] by
- cast to const char* for PyString_FromStringAndSize
- 7:57 PM Changeset [6469] by
- clean up some function declaration isn't a prototype warnings
- 7:49 PM Changeset [6468] by
- make imageextra field non-conditional - much safer (#2205)
- 7:45 PM Changeset [6467] by
- removed inaccurate comment on MAXIMAGESIZE
- 7:39 PM Changeset [6466] by
- oops no &
- 7:06 PM Changeset [6465] by
- add setWKTProjection
Aug 4, 2007:
- 7:44 PM Changeset [6464] by
-
- 7:38 PM Ticket #2205 (imageObj.getBytes() is severely broken) closed by
- fixed: r6463 is related, and makes getBytes use msSaveImageBufferAGG for …
- 7:38 PM Changeset [6463] by
- use msSaveImageBufferAGG for AGG formats #2205
- 7:35 PM Changeset [6462] by
- make sure $(AGG) gets into mapscriptvars #2205
- 9:32 AM Ticket #2201 (msFreeHashItems getting called on an empty hash in freeLayer) closed by
- duplicate: Duplicate of #2203
- 9:27 AM Ticket #2205 (imageObj.getBytes() is severely broken) created by
- Attempting to do imageObj.getBytes() results in a segfault. …
- 8:05 AM Ticket #2204 (gpc_polygon_clip is bad configure test function for agg, sometimes missing) created by
- Even Rouault reports (on mapserver-dev): Currently in configure.in, …
- 7:52 AM Ticket #2203 (Empty METADATA items on MAP, LAYER, and WEB) closed by
- fixed: I applied the msHashIsEmpty check in mapfile.c so that empty metadata …
- 7:51 AM Changeset [6461] by
- A little cleanup in msFreeHashItems as discussed in bug 2203.
- 7:22 AM Changeset [6460] by
- Added msHashIsEmpty() check to the hash writing code in mapfile.c so …
Aug 3, 2007:
- 7:55 PM Changeset [6459] by
- jump right out of msFreeHashItems if the table is empty (#2203)
- 7:49 PM Changeset [6458] by
- msHashIsEmpty (#2203)
- 4:09 PM Ticket #1804 (Setting LAYER EXTENT with OGR VRT Data Source doesn't stop check for ...) closed by
- worksforme: I have tested WMS GetCapabilities? requests with a slight variation of …
- 3:39 PM Ticket #1770 (WFS/OWS Path problem?) closed by
- worksforme: I don't have any information to reproduce this nor do I recall …
- 10:40 AM Ticket #2203 (Empty METADATA items on MAP, LAYER, and WEB) created by
- It seems that we are now keeping empty METADATA blocks around for …
- 8:25 AM Changeset [6457] by
- Driver is AGG/PNG and not AGG/PNG24 (#2195)
- 8:03 AM Ticket #2153 (add GetProcessingKey to layerobj in mapscript) closed by
- fixed
- 8:03 AM Changeset [6456] by
- Added getProcessingKey() to SWIG/MapScript. (bug 2153)
- 7:29 AM Milestone 4.6 release completed
-
- 7:29 AM Milestone 4.8 release completed
-
- 7:28 AM Milestone 4.4 release completed
-
- 7:28 AM Milestone 4.2 release completed
-
- 7:24 AM Ticket #2112 (Create a signed version of mapscript_csharp.dll for .NET ClickOnce ...) closed by
- fixed
- 7:18 AM Changeset [6455] by
- Correct AGG/PNG24 to be AGG/PNG.
- 7:02 AM Changeset [6454] by
- Correct msSaveImageBufferAGG to fit the agg dirviers changes (#2195)
Aug 2, 2007:
- 10:12 PM Ticket #2202 (Infinite loop in msStringConcatenate from msGetErrorString) created by
- This code goes on forever if msAddSymbol fails …
- 9:57 PM Ticket #2201 (msFreeHashItems getting called on an empty hash in freeLayer) created by
- […] This is caused by …
- 7:23 PM Changeset [6453] by
- Added MS_OWS_CELLSIZE macro to compute cellsize from outside image …
- 4:54 PM Changeset [6452] by
- AGG : allocate outputformat using AGG/PNG24 (#2195)
- 3:18 PM Ticket #2199 (memeory leak with labepath object) closed by
- fixed: fix commited in r6451
- 3:17 PM Changeset [6451] by
- Fix memeory leak with labepath object (#2199)
- 3:15 PM Ticket #2200 (memeory leak msImageTruetypePolyline (maplabel.c)) closed by
- fixed: Fixed commited in r6450
- 3:14 PM Changeset [6450] by
- Fix memeory leak msImageTruetypePolyline (#2200)
- 3:12 PM Ticket #2200 (memeory leak msImageTruetypePolyline (maplabel.c)) created by
- msImageTruetypePolyline was using unnecessarly a shape object when …
- 2:16 PM Ticket #2199 (memeory leak with labepath object) created by
- It seems that the labepath object of the labelCacheMemberObj is never …
- 11:59 AM Ticket #2198 (mapswf.c / symbol overhaul problems) closed by
- fixed: Fixed and tested r6449.
- 11:59 AM Changeset [6449] by
- SWF: Fix incorrect symbol assignements (#2198)
- 11:49 AM Ticket #2195 (AGG and output formats) closed by
- fixed: Actually, I've added a quicky test of aggpng24 output in msautotest …
- 11:49 AM Changeset [6448] by
- new test of aggpng24 output
- 11:41 AM Changeset [6447] by
- Regularize AGG support. Support AGG/PNG24 and AGG/JPEG and by default …
- 11:38 AM Ticket #2077 (small leak in msGMLGetNamespaces) closed by
- fixed: Fixed the leak of gmlNamespaceListObj in GetFeature? and …
- 11:36 AM Changeset [6446] by
- Fixed leak of gmlNamespaceListObj in GetFeature? and …
- 11:25 AM Ticket #2198 (mapswf.c / symbol overhaul problems) created by
- Umberto, I think there are a number of places in mapswf.c with stuff …
- 11:17 AM Changeset [6445] by
- removed some unused variables in the quest for a clean build
- 11:17 AM Changeset [6444] by
- Fixed leak of tokens in msWFSDescribeFeatureType (#2077)
- 11:16 AM Ticket #2197 (Cleanup code that strips namespaces in msWFSDescribeFeatureType()) created by
- The following code in msWFSDescribeFeatureType() was introduced in …
- 10:37 AM Changeset [6443] by
- Fixed lead of wfsparams->pszVersion in GetCapabilities? (#2077)
- 10:19 AM Ticket #2059 (Memory Leak in 4.10 completely breaks WMS mode) closed by
- worksforme: I have re-tested this with testcopy with MapServer 4.10.0, 4.10.1 and …
- 9:32 AM Ticket #2196 (Time interpretation and processing) created by
- We've run into some issues with how time is processed (i.e. see #2154, …
- 9:21 AM Ticket #2195 (AGG and output formats) created by
- There are few drivers dified in mapoutput.c for AGG such as …
- 8:47 AM Ticket #2194 (Use of uninitialised value in msCopySymbol()) closed by
- fixed: This was caused by the loop that copies points[] in msCopySymbol() …
- 8:46 AM Changeset [6442] by
- Avoid use of uninitialised memory in msCopySymbol() (#2194)
- 8:44 AM Ticket #2194 (Use of uninitialised value in msCopySymbol()) created by
- Running valgrind on the 'testcopy' program (compile it using make …
- 8:07 AM Changeset [6441] by
- Renamed map.h to mapserver.h (ticket #1437)
- 6:55 AM Ticket #2162 (Response to a WMS getcapabilities returns ContactInformation (msautotest)) closed by
- wontfix: I found that an empty ContactInformation? element was ugly (even if …
- 6:36 AM Changeset [6440] by
- Updated AGG for HATCH and VECTOR polygon fills. (bug 2191)
- 6:21 AM Ticket #2193 (Scale computation has changed from 4.10 to 5.0) created by
- I have found a problem with the MAXSCALE computation in mapserver. …
- 4:34 AM Ticket #2154 ([SOS-Server] eventTime not working) closed by
- fixed: Tested on svn trunk. Works. Here's an exmaple (my mapfile defines …
Aug 1, 2007:
- 12:09 PM Changeset [6439] by
- Tag for rel-5-0-0-beta2
- 12:05 PM Changeset [6438] by
- Creating tags/rel-5-0-0-beta2
- 12:04 PM Changeset [6437] by
- Updated for 5.0.0-beta2
- 12:01 PM Changeset [6436] by
- Adding the Oracle Spatial changes in the history file
- 11:23 AM Ticket #1845 (Compiler warnings with gcc 4.x on maporaclespatial.c) closed by
- fixed: I committed the code with the fix in the SVN this afternoon. The …
- 11:22 AM Ticket #2056 (Memory access error with oraclespatial multipolygons) closed by
- fixed: I committed the code with the fix in the SVN this afternoon. The …
- 11:21 AM Ticket #1961 (Oracle-Spatial: Crash) closed by
- fixed: I committed the code with the fix in the SVN this afternoon. The …
- 11:19 AM Ticket #1736 (WMS getFeatureInfo with OracleSpatial layer crashes) closed by
- fixed: I committed the code with the fix in the SVN this afternoon. The …
- 11:16 AM Changeset [6435] by
- Fixing Oracle bugs: 1662, 1736, 1845, 1961, 2056
- 8:29 AM Ticket #2192 (segfault if fontset references inexistant font paths/files) created by
- in function msPolylineLabelPath in mapprimitive.c there's a call to …
- 8:25 AM Ticket #1426 (EPSG lookup done for all layers) closed by
- duplicate: There is already ticket #1976 addressing this. Closing as duplicate.
- 7:24 AM Ticket #2169 (Do we still need 'isachild' member in styleObj?) closed by
- fixed: Done. styleObj.isachild member removed in r6434 (will be in 5.0.0-beta2).
- 7:23 AM Changeset [6434] by
- Removed unused styleObj.isachild member (#2169)
- 6:40 AM Ticket #2173 (AGG and GD alpha values are incompatible) closed by
- fixed: Thomas wanted to make sure that this made it in today's beta2, so I …
- 6:35 AM Changeset [6433] by
- Bypass gdImageSetPixel() in msAlphaGD2AGG() to avoid special treatment …
- 5:02 AM Ticket #2173 (AGG and GD alpha values are incompatible) reopened by
- sorry reopening :( the gd alpha values are 0 to 127 so that …
Jul 31, 2007:
- 10:19 PM Ticket #2173 (AGG and GD alpha values are incompatible) closed by
- fixed: I'm going to close this one now. We can open up more specific tickets …
- 10:18 PM Changeset [6432] by
- Updating HISTORY.TXT.
- 10:12 PM Changeset [6431] by
- Fixed AGG ellipse markers, they were twice the size they should be.
- 9:57 PM Changeset [6430] by
- Filled missing AGG marker code for VECTOR and ELLIPSE symbols.
- 9:53 PM Ticket #2191 (AGG missing a few symbol options that GD has) created by
- Currently, AGG rendering does not support all the options that GD …
- 9:25 PM Changeset [6429] by
- On last transparent scratch image merging in mapgd.c.
- 5:42 PM Ticket #2190 (mappostgis.c:msPOSTGISLayerRetrievePK() is malloc'ing improperly) created by
- […]
- 12:58 PM Changeset [6428] by
- Added missing line at end of license text
- 12:57 PM Changeset [6427] by
- Added std copyright header
- 12:04 PM Changeset [6426] by
- SOS: Turn layer off if eventTime is not in the sos_offering_timeextent …
- 8:19 AM Changeset [6425] by
- removed unused variable
- 8:10 AM Changeset [6424] by
- WFS FeatureId? request : return exception when layer is not found (#2102)
- 7:44 AM Changeset [6423] by
- Added link to dynamic charting howto
- 7:41 AM Ticket #1372 (if RESX not equal to RESY only first band contains data) closed by
- fixed: Tested with version 4.99 on a single data file, and with a tileindex, …
Jul 30, 2007:
- 9:26 PM Changeset [6422] by
- Fixed a problem when ANTIALIAS TRUE was set with AGG polygon fills.
- 8:58 PM Changeset [6421] by
- Fixed a couple of compile warnings. Removed uncessary blocks from …
- 8:17 PM Changeset [6420] by
- Fixed AGG line drawing to use the style outline color if the primary …
- 3:32 PM Ticket #2189 (QueryByAttributes with Sde Layers) created by
- I have been developing a website for Mapserver using c# mapscript. I …
- 2:49 PM Changeset [6419] by
- Correct bugs related to WFS query by featureid support (#2102)
- 12:01 PM Ticket #1727 (wrong arrguments order in msAddLabel) closed by
- fixed: According to the first comment from Steve, this was fixed for the 4.10 …
- 11:53 AM Ticket #1968 (calling setRotation() causes a Fatal Error) closed by
- fixed: I think the changes in trunk are sufficient. I'm not going to try and …
- 11:40 AM Ticket #1347 (WMS GetMap and SVG) closed by
- fixed: SVG is now valid for wms getmap request r6418
- 11:39 AM Changeset [6418] by
- WMS : Add svg as a supported format for GetMap? request (#1347)
- 11:00 AM Ticket #2177 (AGG anti-aliasing does not appear to be working) closed by
- fixed: Ok, Thomas Bonfort has been very helpful is putting the finishing …
- 10:53 AM Ticket #1943 (RFC 21: MapServer Raster Color Correction) closed by
- fixed: Actually closing!
- 3:23 AM Ticket #1800 (Add dynamic charting capabilities to mapserver) closed by
- fixed: I created a howto documenting dynamic charting here: …
Jul 29, 2007:
- 8:28 AM Ticket #2188 (Building with Agg support on debian etch fails) closed by
- fixed: these debugging statements where removed just after the snapshot for …
Jul 28, 2007:
- 7:53 AM Ticket #2188 (Building with Agg support on debian etch fails) created by
- Building mapagg.cpp on Debian etch fails. I was able to work around …
- 7:27 AM Changeset [6417] by
- treat AGG/ as a legal WMS format class (#2187)
- 7:26 AM Ticket #2187 (WMS Request for DRIVER AGG/PNG claims 'invalid output format') closed by
- fixed: Fixed (r6416) ... should appear in beta2. […] This bug resulted …
- 7:24 AM Changeset [6416] by
- treat AGG/ as a legal WMS format class (#2187)
- 7:07 AM Ticket #2187 (WMS Request for DRIVER AGG/PNG claims 'invalid output format') created by
- I edited a mapfile to have an outputformat like: OUTPUTFORMAT NAME …
Jul 27, 2007:
- 2:23 PM Ticket #1261 ([WMS} time support : overriding Filter paramter) closed by
- fixed: Thnaks for the tests. closing bug.
- 12:14 PM Changeset [6415] by
- Fixed ReST formatting for Plone site
- 12:02 PM Changeset [6414] by
- Added font and priority to list of style properties that accept binding
- 11:58 AM Changeset [6413] by
- Correct WMS time overriding Filter paramter on a postgis layer (#1261)
- 11:57 AM Changeset [6412] by
- Correct WMS time overriding Filter paramter on a postgis layer (#1261)
- 11:31 AM Ticket #2183 (configure "test -e" is not portable) closed by
- fixed: I was wrong, we don't need 'test -r' as 'test -f' is portable and …
- 11:30 AM Changeset [6411] by
- Fixed AGG configure option to use 'test -f' instead of 'test -e' which …
- 11:12 AM Ticket #2186 (Update README.CONFIGURE for v5.0) created by
- The README.CONFIGURE in the source tree needs to be updated with the …
- 11:10 AM Changeset [6410] by
- More fixes to formatting of configure --help (#2182)
- 11:06 AM Ticket #2182 (configure --help output format) closed by
- fixed: Fixed formatting in r6409. In addition to the indent, I also fixed …
- 11:04 AM Changeset [6409] by
- Fixed formatting of configure --help (#2182)
- 10:52 AM Changeset [6408] by
- Applied rendering patch for GD/AGG as described by Thomas in bug 2173.
- 10:37 AM Ticket #2180 ([PATCH] Fix reprojection bug in mapwcs.c) closed by
- fixed: The patch has been applied in the 4.10 branch (for 4.10.3) and in …
- 10:36 AM Changeset [6407] by
- WCS : Fixed resampling/reprojecting for tileindex datasets (#2180)
- 10:34 AM Changeset [6406] by
- correct (post fix) versions
- 10:33 AM Changeset [6405] by
- WCS : Fixed resampling/reprojecting for tileindex datasets (#2180)
- 10:31 AM Changeset [6404] by
- added wcs test (per bug #2180), use tileindex
- 10:15 AM Ticket #2185 (Certain configure options cause mapscript csharp make test to fail ...) created by
- If '--enable-coverage' or '--with-fastcgi=/path' is included in the …
- 10:12 AM Ticket #2184 (make test for mapscript_csharp fails in 64-bit) created by
- After mapserver/mapscript_csharp have been compiled on a 64-bit …
- 9:18 AM Changeset [6403] by
- Avoid warnings.
- 3:46 AM Ticket #2183 (configure "test -e" is not portable) created by
- test -e, as used in the AGG section of configure, is not considered …
- 2:59 AM Ticket #2182 (configure --help output format) created by
- The format of the configure --help output could be improved. Line …
Jul 26, 2007:
- 11:10 PM Ticket #2176 (CGI map_size is not working) closed by
- fixed: Fixed (rev. 6402)... Steve
- 11:09 PM Changeset [6402] by
- Fixed map-level URL configuration (e.g. map.size or map.imagecolor). …
- 4:09 PM Changeset [6401] by
- Hide AssemblyInfo?.cs to prevent from the deletion by make clean.
- 4:01 PM Changeset [6400] by
- Remove the old AssemblyInfo?.cs
- 3:57 PM Changeset [6399] by
- Hide AssemblyInfo?.cs to prevent from the deletion by make clean.
- 3:32 PM Changeset [6398] by
- Create a signed version of mapscript_csharp.dll (Ticket #2112)
- 2:43 PM Ticket #2181 ([PATCH] Fix handling of NODATA values (for DTED files)) created by
- Currently, when doing WCS on DTED files (whose NODATA value is …
- 1:36 PM Changeset [6397] by
- Add mapagg.obj in the windows makefile
- 10:26 AM Ticket #2180 ([PATCH] Fix reprojection bug in mapwcs.c) created by
- Producing non-square pixels or reprojected results with MapServer WCS …
- 2:58 AM Ticket #2179 (Oracle Spatial doesn't scale well with concurrent connections) created by
- Hi all, I perform some performance tests on mapserv (CGI and FASTCGI), …
Jul 25, 2007:
- 9:18 PM Changeset [6396] by
- if the user provides a mapping for 255, do not override it (bug #2167)
- 6:12 PM Ticket #2167 (PROCESSING LUT= always shows highest value as white (mapdrawgdal.c)) closed by
- fixed: Sander, I have applied this simplified patch in trunk as r6395. It …
- 6:11 PM Changeset [6395] by
- if the user provides a mapping for 255, do not override it (bug #2167)
- 4:31 PM Ticket #2178 (AGG code has debug logging enabled by default) closed by
- fixed: Removed at revision 6394. - Steve
- 4:30 PM Changeset [6394] by
- Removed debug logging from mapagg.cpp. (bug 2178)
- 4:30 PM Ticket #2178 (AGG code has debug logging enabled by default) created by
- As part of the AGG development there was a log file opened and written …
- 3:59 PM Changeset [6393] by
- Backing out the alpha channel reset changes (with AGG) to mapdraw.c.
- 1:43 PM Ticket #2116 (Adding namespace support for the MapScript C# interface) closed by
- fixed
- 12:24 PM WikiStart edited by
- (diff)
- 11:33 AM Ticket #2177 (AGG anti-aliasing does not appear to be working) created by
- This mapfile was working when the labels FOLLOW was broken, but now …
- 11:25 AM Ticket #2176 (CGI map_size is not working) created by
- CGI map_size is not working and it returns the mapsize set in the …
- 10:06 AM Changeset [6392] by
- Tag 5.0.0-beta1 source
- 10:05 AM Changeset [6391] by
- Create tag rel-5-0-0-beta1
- 9:59 AM Changeset [6390] by
- Updated for v5.0.0-beta1
- 9:36 AM Changeset [6389] by
- Renamed map.h to mapserver.h (#1437)
- 7:27 AM Ticket #770 (MapServer/GEOS integration) closed by
- fixed: This is long complete... Steve
- 5:49 AM Ticket #2175 (WMS BBOX issues) created by
- When used as a WMS server mapserver will re-create the WMS BBOX by …
- 5:21 AM Ticket #2174 (Apache/ArcSDE connections prevent to kill mapserv processes) created by
- In some cases, Apache does not destroy all the mapserver processes …
Jul 24, 2007:
- 10:07 PM Changeset [6388] by
- Fixed a bug in loadExpressionString() that kept the lexer from …
- 8:40 PM Changeset [6387] by
- Added code to msDrawLayer() to reset the alpha channel to 0 after …
- 8:40 PM Ticket #2173 (AGG and GD alpha values are incompatible) created by
- AGG and GD, it turns out, interpret alpha channel values totally …
- 1:12 PM Changeset [6386] by
- Added note about RFC-17: dynamic alloc of layers, classes, etc.
- 11:38 AM Ticket #2172 (mscopyclass should increase the numstyles after a copy) closed by
- fixed: Commited fix in r6385. Closing it.
- 11:37 AM Changeset [6385] by
- msCopyClass should increase the numstyles after a copy(#2172)
- 11:35 AM Ticket #2172 (mscopyclass should increase the numstyles after a copy) created by
- @@ -418,6 +418,8 @@ msSetError(MS_MEMERR, "Failed to copy …
- 10:55 AM Ticket #2171 (Leaks in maphttp.c) created by
- msHTTPExecuteRequests() is leaking some curl data structures in error …
- 9:35 AM Changeset [6384] by
- Fixed lead of pasReqInfo in case of error in msHTTPGetFile()
- 7:52 AM Changeset [6383] by
- Added note about deprecated members from RFC-26 in PHP MapScript?
- 7:43 AM Changeset [6382] by
- Keep transparency (renamed to opacity) as deprecated for now (RFC 26, …
- 7:36 AM Ticket #2119 (MapServer terminogy cleanup (RFC 26).) closed by
- fixed: I have updated PHP MapScript? in r6381 with the changes for scale -> …
- 7:35 AM Ticket #2170 (Remove deprecated scale and symbol.style members in PHP MapScript) created by
- In r6381 (ticket #2119, RFC-26), we have renamed scale to scaledenom …
- 7:23 AM Changeset [6381] by
- Convert symbol style to pattern and scale to scaledenom (RFC 26, …
- 6:50 AM Changeset [6380] by
- Add ifdef around calls to msOWS functoions (#2102)
- 6:25 AM Changeset [6379] by
- Rename symbol style to pattern (RFC-26, ticket #2119)
Jul 23, 2007:
- 9:51 PM Changeset [6378] by
- Updated MapServer objects to append the keyword 'denom' on to …
- 9:33 PM Changeset [6377] by
- Updated mapscript.i to use mapserver.h instead of map.h.
- 9:03 PM Changeset [6376] by
- WFS : support query by featureid for a Get Request (#2102)
- 8:32 PM Changeset [6375] by
- Migrated the symbolObj parameter STYLE to PATTERN. Mapfile and symbol …
- 7:53 PM Changeset [6374] by
- Renamed map.h to mapserver.h (ticket #1437)
- 7:41 PM Ticket #1437 (Change main header file name (or provide alternative)) closed by
- fixed: It has been decided by vote of the PSC on the -dev list to rename …
- 7:37 PM Changeset [6373] by
- Renamed map.h to mapserver.h (ticket #1437)
- 6:34 PM Changeset [6372] by
- Uncommented call to msUpdateMapFromURL(). (bug 2143)
- 6:32 PM Changeset [6371] by
- RFC 31 initial submission. (bug 2143)
- 3:17 PM Changeset [6370] by
- wfs support of query by featureid (#2102)
- 2:25 PM Changeset [6369] by
- Avoid attemps to read styles[0] when not set (#302)
- 2:02 PM Ticket #302 (Use semi-dynamic allocation for layer, classes, styles, etc.) closed by
- fixed: I have committed r6368 for dynamic allocation of styles as per …
- 1:52 PM Changeset [6368] by
- Implemented RFC-17 for styles: got rid of MS_MAXSTYLES limit, replaced …
- 11:04 AM Changeset [6367] by
- bring forward 4.10 bug fixes
- 8:07 AM Changeset [6366] by
- Fix indent and replace tabs with spaces
- 7:31 AM Ticket #2169 (Do we still need 'isachild' member in styleObj?) created by
- While working on #302, I noticed the isachild member in the …
- 7:19 AM Ticket #2159 (dynamic charting does not support AGG renderer) closed by
- fixed: Thanks Thomas. I have committed your latest patch (add rendering of …
- 7:18 AM Changeset [6365] by
- Added gd rendering of outlines and offsets (ThomasB, ticket #2159)
- 6:38 AM Changeset [6364] by
- Added MS_TOKENIZE_VALUE, MS_TOKENIZE_NAME definitions and fixed 2 …
- 5:32 AM Changeset [6363] by
- Add Support of cssParameters stroke-opacity and fill-opacity (#2152)
Note: See TracTimeline for information about the timeline view.
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http://trac.osgeo.org/mapserver/timeline?from=2007-08-22T09%3A31%3A36-0700&precision=second
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CC-MAIN-2016-22
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refinedweb
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Sometimes, we wanna couple multiple dataframes together. In this note, I use
df as
DataFrame,
s as
Series.
Libraries
import pandas as pd import numpy as np
Coupling dfs with
merge()
There are 4 types of merging, like in SQL.
- Inner: only includes elements that appear in both dataframes with a common key.
- Outer: includes all data from both dataframes.
- Left: includes all of the rows from the “left” dataframe along with any rows from the “right” dataframe with a common key; the result retains all columns from both of the original dataframes.
- Right: includes all of the rows from the “right” dataframe along with any rows from the “left” dataframe with a common key; the result retains all columns from both of the original dataframes.
On the same column name,
# left df_left = pd.merge(left=df1, right=df2, how='left', on='Col_1', suffixes=('_df1', '_df2')) # right df_right = pd.merge(left=df1, right=df2, how='right', on='Col_1', suffixes=('_df1', '_df2')) display_side_by_side(df1, df2, df_left, df_right)
# inner (defaut) df_inner = pd.merge(left=df1, right=df2, on='Col_1', suffixes=('_df1', '_df2')) # outer df_outer = pd.merge(left=df1, right=df2, how='outer', on='Col_1', suffixes=('_df1', '_df2')) display_side_by_side(df1, df2, df_inner, df_outer)
On the different column names,
# left df_left = pd.merge(left=df1, right=df2, how='left', left_on='Col_1', right_on='Col_X', suffixes=('_df1', '_df2')) display_side_by_side(df1, df2, df_left)
The result keeps both
Col_1 and
Col_X while in the case of the same column name, there is only 1 column. Other words, in this case, we only want to keep
Col_1 and don’t need
Col_X. How to do that?
df_left = df1.set_index('Col_1').join(df2.set_index('Col_X'), how="left", lsuffix="_df1", rsuffix="_df2").reset_index() display_side_by_side(df1, df2, df_left)
Concatenate dfs with
concat()
# axis=0 (default) df_concat_0 = pd.concat([df1, df2]) # the same columns df_concat_1 = pd.concat([df1, df2], axis=1) # the same rows df_concat_0_idx = pd.concat([df1, df2], ignore_index=True) # ignore_index=True prevent duplicating indexes display_side_by_side(df1, df2) display_side_by_side(df_concat_0, df_concat_1, df_concat_0_idx)
Combine 2 dataframes with missing values
We consider a situation in that we need to combine 2 dfs containing missing values in each. The missing values will be filled by taking from the others. For example, the value of
C in the left df can be fulfilled by the value of
C in the right df.
df_comb = df1.copy() # we don't want to change df1 df_new = df_comb.fillna(df2) display_side_by_side(df1, df2, df_comb, df_new)
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https://dinhanhthi.com/data-combining
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CC-MAIN-2020-29
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refinedweb
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Find the number of subsets of an array having a given XOR value
Reading time: 30 minutes | Coding time: 10 minutes
We are given an array of size N and a value M, we have to find the number of subsets in the array having M as the xor value of all elements in the subset. This can be solved using Dynamic Programming in linear time.
Example:
Input: arr[] = {1, 2, 3, 4}, M = 4
Output: 2
The subsets are:
{4}, {1, 2, 3, 4}
The XOR of other subsets like {1, 2, 3} or {1, 3} is not 4 and hence, these subsets are not included in our count.
We will solve this using two approaches:
- Naive approach O(2^N) time
- Dynamic Programming (N * K) time
Naive approach O(2^N)
In naive approach we find all the subsets of the given array by recursion and find xor of all elements present in them and count how many xor values are equal to m.
The time complexity of such a technique is O(2^length) where length signifies the length of the given array.
Efficient approach O(N * K)
We will use Dynamic programming approach to solve this problem efficiently. The working will be similar to what we did in Number of subsets with sum divisible by M.
In the table DP[i][j] signifies number of subsets with xor j till the elements from 1st to ith are taken into consideration.
DP[i][j] = number of subsets with XOR 'j' till the elements from 1st to ith
Formula used-:
DP[i][((j-1)^arr[i-2])+1] = DP[i-1][((j-1)^arr[i-2])+1] + DP[i-1][j];
If we are at ith element of the array and traverse the row for the (i-1)th element we get the subsets number of subsets of all possible xor values.
For the ith element if we get DP[i-1][j]>0 it means that xor value j-1 has that many number of subsets. So we take xor of arr[i] with this value and get the resulting number of subsets of the new xor value (say x) by adding the previous number of subsets of x which will be given by DP[i-1][((j-1)^arr[i-2])+1] and number of subsets of value j-1 which is equal to DP[i-1][j].
For generating the values in DP table we take DP[1][1]=1 which represents there is always a null subset having xor value 0. This will be the base case for the approach USED.
Implementation
The maximum possible xor value of any subset will be pow(2,((log2(max(arr))+1))) – 1. Let this number be equal to k.
So we take the number of columns of the 2-D array to be k+2 and number of rows to be N+2. Now we define the array as DP[N+2][k+2].
For the given example:
arr[]={1,2,3,4} k=pow(2,log2(4)+1)-1=7
We set DP[1][1]=1 as there is always a subset i.e. (null set) which has xor value=0.
Now start traversing the array from i=2 and for each DP[i][j] we check if DP[i-1][j]>0 we go to element DP[i][j^arr[i-2]+1) and increase it's value by DP[i-1][j]+DP[i-1][j^arr[i-2]+1] as now the subset count of j^arr[i-2] will increase by the number of subsets having xor value as j.
Stepwise visualization of DP table
- We traverse the given array and update the values in the DP table accordingly.Like arr[0]=1 so we check which subset value in the above row has frequency>0 here it is 0 so we update the value of DP[2][0^1+1] by DP[1][1]+DP[1][2].
- Likewise we do it for arr[1]=2.
- Likewise for arr[2]=3
- Likewise for arr[3]=4
C++ Implementation
Following is the C++ Implementation of our Dynamic Programming approach:
#include<bits/stdc++.h> using namespace std; #define ll long long int int main() { ll arr[]={1,2,3,4}; ll m=4; ll i,j,l=4; ll max_ele=0; //Calculating the maximum possible xor value for(i=0;i<l;i++) { max_ele=max(max_ele,arr[i]); } int k=(1 << (int)(log2(max_ele) + 1) ) - 1; ll DP[l+2][k+2]={0}; DP[0][0]=-1; DP[1][0]=-1; //filling all possible xor values in the first row for(i=1;i<k+2;i++) { DP[0][i]=i-1; DP[1][i]=0; } //filling all the array elements in the first column for(i=2;i<l+2;i++) { DP[i][0]=arr[i-2]; } DP[1][1]=1; //Filling the DP table //according to given logic for(i=2;i<l+2;i++) { for(j=1;j<k+2;j++) { if(DP[i-1][j]!=0) { DP[i][((j-1)^arr[i-2])+1] = DP[i-1][((j-1)^arr[i-2])+1]+DP[i-1][j]; } } for(j=1;j<k+2;j++) { DP[i][j]=max(DP[i-1][j],DP[i][j]); } } for(i=0;i<l+2;i++) { for(j=0;j<k+2;j++) { cout<<DP[i][j]<<"\t"; } cout<<"\n"; } //counting the number of subsets //having given xor value ll ans=DP[l+1][m+1]; cout<<"Number of subsets is:"<<ans<<"\n"; return 0; }
Output:
Number of subsets is:2
Complexity
The time complexity of the given approach is O(k * n) where k is the maximum possible xor value and n is the total number of elements in the array.
The space complexity of our approach is O(N * K) as well.
Following is the summary:
With this, you have the complete knowledge of this problem. Enjoy.
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https://iq.opengenus.org/number-of-subsets-with-given-xor-value/
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Tips for designing payloads
Getting the different components in your systems talking nicely to one another relies on a rather mundane but crucial detail: a good data structure in the message payloads. This article will pick out some of the best advice we have for getting your Apache Kafka data payloads well designed from the very beginning of your project.
Use all the features of Apache Kafka records
The events that we stream with Kafka can support headers as well as keys and the main body of the payload. The most scalable systems use all these features appropriately.
Use the header for metadata about the payload, such as the OpenTelemetry trace IDs. It can also be useful to duplicate some of the fields from the payload itself, if they are used for routing or filtering the data. In secure systems, intermediate components may not have access to the whole payload, so putting the data in the header can expose just the appropriate fields there. Also consider that, for larger payloads, the overhead of deserializing can be non-trivial. Being able to access just a couple of fields while keeping the system moving can help performance, too.
The keys in Apache Kafka typically do get more attention than the headers, but we should still make sure we are using them as a force for good. When a producer sends data to Kafka, it specifies which topic it should be sent to. The key usually defines which partition is used. If the key isn’t set, then the data will be spread evenly across the partitions using a round-robin approach. For a lot of unrelated events in a stream, this makes good use of your resources.
If the key you’re using doesn’t vary much, your events can get bunched into a small number of partitions (rather than spread out). When this happens, try adding more fields to give more granular partition routing. Keep in mind that the contents of each partition will be processed in order, so it still makes sense to keep logical groupings of data.
For example, consider a collection of imaginary factories where all the machines can send events. Mostly they send
sensor_reading events, but they can also send
alarm events, that are like a paper jam in the printer but on a factory scale! Using a key like this will give us a LOT of data on one partition:
{ "type": "sensor_reading" }
So we could add another field to the key for these readings, maybe to group them by factory location:
{ "type": "sensor_reading", "factory_id": 44891 }
Combining the type and factory in the key ensures that records of the same event type and the same factory will be processed in the order they were received. When it comes to designing the payloads, thinking about these aspects early on in the implementation process can help avoid performance bottlenecks later.
Data structures: nested data, or simple layout
No matter how certain I am that this payload will only ever contain a collection of things, I always use an object structure rather than making the data an array at the top level. Sometimes, it just leaves a rather lonely fieldname with a collection to take care of. But when things change and I do need to add an extra field, this “one weird trick” makes me very grateful.
Make no mistake, it’s not foresight. It’s the scars of the first API I ever shipped having to move to v1.1 within a week of launch for precisely this reason. Learn from my mistakes!
In general, it’s also helpful to group related fields together; once you get 30 fields in a payload and they are sorted alphabetically then you will wish you had done something differently! Here’s an example showing what I mean:
{ "stores_request_id": 10004352789, "parent_order": { "order_ref": 777289, "agent": "Mr Thing (1185)" }, "bom": [ {"part": "hinge_cup_sg7", "quantity": 18}, {"part": "worktop_kit_sm", "quantity": 1}, {"part": "softcls_norm2", "quantity": 9} ]}
Using the
parent_order object to keep the order ref, its responsible person, and any other related data together makes for an easily navigable structure, more so than having those fields scattered across the payload. It also avoids having to artificially group the fields using a prefix. Don't be afraid to introduce extra levels of data nesting to keep your data logically organised.
How much data to include is another tricky subject. With most Kafka platforms limiting payloads to 1MB, it’s important to choose carefully. For text-based data, 1MB is quite a lot of information, especially if a binary format such as Avro or Protobuf is used (more on those in a moment). As a general rule of thumb, if you are trying to send a file in a Kafka payload, you are probably doing it wrong!
These design tradeoffs are nothing new and I rely mostly on the prior art in the API/webhooks space to inform my decisions. For example, hypermedia is the practice of including links to resources rather than the whole resource. Publishing messages that will cause every subscriber to make follow-on calls is a good way to create load problems for your server but hypermedia can be a useful middle ground, especially where the linked resources are cacheable.
Data Formats: JSON, Avro … these are not real words
Wading through the jargon of data formats is a mission by itself, but I’d like to give some special mentions to my favourites!
JSON: Keep it simple JSON formats are very easy to understand, write, read and debug. They can use a JSON Schema to ensure they fulfil an expected data structure, but you can equally well go freeform for prototyping and iterating quickly. For small data payloads, I often start here and never travel any further. However, JSON is fairly large in size for the amount of data it transmits, and it also has a rather relaxed relationship with data types. In applications where either or both of these issues cause a problem, then I move on from JSON and choose something a bit more advanced.
Avro: Small and schema-driven Apache Avro is a serialisation system that keeps the data tidy and small, which is ideal for Kafka records. The data structure is described with a schema (example below) and messages can only be created if they conform with the requirements of the schema. The producer takes the data and the schema, produces a message that goes to the kafka broker, and registers the schema with a schema registry. The consumers do the same in reverse: take the message, ask the schema registry for the schema, and assemble the full data structure. Avro has a strong respect for data types, requires all payloads conform with the schema, and since data such as fieldnames is encoded in the schema rather than repeated in every payload, the overall payload size is reduced.
Here’s an example Avro schema:
{ "namespace": "io.aiven.example", "type": "record", "name": "MachineSensor", "fields": [ {"name": "machine", "type": "string", "doc": "The machine whose sensor this is"}, {"name": "sensor", "type": "string", "doc": "Which sensor was read"}, {"name": "value", "type": "float", "doc": "Sensor reading"}, {"name": "units", "type": "string", "doc": "Measurement units"} ] }
There are other alternatives, notably Protocol Buffers, known as ProtoBuf. It achieves similar goals by generating code to use in your own application, making it available on fewer tech stacks. If it’s available for yours, it’s worth a look.
A note on timestamps
Kafka will add a publish time in the header of a message. However it can also be useful to include your own timestamps for some situations, such as when the data is gathered at a different time to when it is published, or when a retry implementation is needed. Also since using Apache Kafka allows additional consumers to reprocess records later, a timestamp can give a handy insight into progress through an existing data set.
If I could make rules, I’d make rules about timestamp formats! The only acceptable formats are:
- Seconds since the epoch
1615910306
- ISO 8601 format
2021-05-11T10:58:26Zincluding timezone information, I should not have to know where on the planet on which day of the year this payload was created.
Design with intention
With the size limitations on the payloads supported by Apache Kafka, it’s important to only include fields that can justify their own inclusion. When the consumers of the data are known, it’s easier to plan for their context and likely use cases. When they’re not, that’s a more difficult assignment but the tips shared here will hopefully set you on a road to success.
Further reading
If you found this post useful, how about one of these resources to read next?
- Getting Started with Apache Kafka on Aiven
- Apache Kafka and the schema registry (with Java code examples)
- The Apache Avro project
- Another open standards project, OpenTelemetry to find out more about adding tracing to your Kafka applications
Originally published at.
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https://lornajane.medium.com/tips-for-designing-payloads-7d35690b5ffa?responsesOpen=true&source=user_profile---------5-------------------------------
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, 2002-11-16 through 2002-11-30
++++++++++++++++++++++++++++++++++++++++++++++++++
This is a summary of traffic on the `python-dev mailing list`_ between
November 16, 2002 and November 30, sixth summary written by Brett Cannon (back in my groove).
All summaries are now, I cannot guarantee you will be able to run the text version
of this summary through Docutils_ as-is. If you want to do that, get
an original copy of the text file.
.. _python-dev mailing list:
.. _Docutils:
.. _reST:
.. _reStructuredText:
======================
Summary Announcements
======================
Nothing to report to speak of. Uh, go to PyCon_ . =)
.. _PyCon:
====================
`bsddb3 imported`__
====================
__
Martin v. Loewis merged bsddb3 3.4.0 into CVS under the name
``bsddb``. The old ``bsddb`` module is now no longer compiled by
default; if it does get compiled, though, it ends up with the name
``bsddb185``. Barry Warsaw also requested that the extensive testing
suite be incorporated and "run it only with a regrtest -u option".
Martin wasn't sure how Barry wanted them incorporated, though, since
there are multiple files to the test and most testing suites in the
stdlib are a single file. Barry suggested that the testing files be
put in a directory with the package and that test_bsddb.py just call
the tests in that directory, much like how the email package does it.
They were integrated and some errors and warnings were found that are
being dealt with.
It was also agreed upon that development will be moved over to Python
so as to keep the module in Python sync'ed up properly and to keep
poor Martin from having to import the files into Python's CVS
constantly.
=======================
`Licensing question`__
=======================
__
David Abrahams asked about a licensing issue with Boost.Python_ (it
is a free library that "enables seamless interoperability between C++"
and Python) and it's modified Python.h_ file that it uses. Originally
there was no license at the top of that file, but that does not work
for some corporations using Boost. So David stuck his own license at
the top and asked if this is the right thing to do.
Guido asked him to provide the PSF_ license_ at the top of the file
and to mention what changes he made. The copyright had been added to
the file for Python 2.2.2.
.. _Boost.Python:
.. _Python.h:
.. _PSF:
.. _license:
=========================
`Re: PyNumber_Check()`__
=========================
__
M.A. Lemburg noticed that PyNumber_Check()'s semantics on what will
cause it to return had changed. He asked if it should check whether
one of "nb_int, nb_long, nb_float is available (in addition to the
tp_as_number slot)". Guido responded that he would like to see it
deprecated. We got a history lesson of how PyNumber_Check() was
written "when the presence or absence of the as_number "extension" to
the type object was thought to be useful". Regardless, Guido said
that testing like this does not prove something is a "number" and if
you wanted to test this way you could do it yourself.
In response, MAL said that perhaps PyNumber_Check() should be changed
so that it returned true for something that is "usable as input to
float(), int() or long()". Guido said that would be fine "as long as
we all agree that that's *exactly* what they check for, and as long as
we agree that there may be overlapping areas" for the various
Py*_Check() functions. Guido later said testing for nb_int, nb_long,
and nb_float was fine.
===================================================
`Plea: can modulefinder.py move to the library?`__
===================================================
__
Just van Rossum wanted to move Freeze's modulefinder.py_ into the
stdlib so that it can be distributed with binary releases. In case
you don't know what modulefinder.py does, it attempts to find all pure
Python module dependencies for a pure Python module. In other words,
it checks what the module imports and if it is a Python file, and if
it is, records that; it repeats this for all modules it finds,
creating a listing of modules needed for the module to run.
Guido said that the module needed some work before it could be
considered; it had ``print`` statements that were unneeded outside of
Freeze and it had no documentation. Just agreed that the
documentation needed to be done. As for the ``print`` statements,
though, they only come out when ``debug`` is set to true; by default
it is false. Guido said that was fine and agreed with the removal
of the Windows-specific ``print`` statements.
Thomas Heller later said in `another thread`_ that `patch #643711`_
was opened primarily for him and Just to do work in but that everyone
was invited to help out.
.. _another thread:
.. _modulefinder.py:
.. _patch #643711:
============================
`Dictionary Foolishness?`__
============================
__
Raymond Hettinger suggested having "dictionaries support the
repetition" to allow one to create a dictionary with enough space as
specified by the repetition::
>>> [0] * n # allocate an n-length list
>>> {} * n # allocate an n-element dictionary
Aahz recalled that dictionaries are resized upon adding to a
dictionary and they could theoretically grow smaller. That would seem
to possibly limit the usefulness of this idea. Guido then voted -1
(practically a death wish for an idea unless people clamor for it)
saying that it relied too much on "arbitrary magic by side effect".
He said if people *really* wanted this a method could be proposed.
=============================
`dict() enhancement idea?`__
=============================
__
Just van Rossum suggested overloading the dictionary constructor so
that arguments that went to ``**kwargs`` would be used to create the
dictionary (this can be seen in the "`Python Cookbook`_" as recipe 1.2
or online at).
This is desired because that means cleaner code for creating dicts::
>>> dict(pigs='!fly', birds='fly')
Barry commented that he liked it and had something similar in his
code for Mailman_ . Thomas Heller voted +1 for it and also said that
he used the idiom. Raymond Hettinger and myself also voted +1 for it.
.. _Python Cookbook:
.. _Mailman:
===========================================
`Yet another string formatting proposal`__
===========================================
__
Oren Tirosh proposed something (read the title to figure out what).
He proposed the following syntax::
>>> "\(a) + \(b) = \(a+b)\n"
>>> r"\(a) + \(b) = \(a+b)\n".cook()
The advantages, according to Oren, are that it would not require
introducing the use of a new symbol like ``$``, nor a new string
prefix nor a new method. The ``.cook()`` method would be used to
evaluate raw strings at a later point; it would draw arguments from
the local and global namespace. The biggest drawback was
unfamiliarity for programmers.
Frederik Lundh pointed out that ``\(`` is "commonly used to escape
parentheses in regular expression strings" (Effbot wrote re_ , so he
should know). Oren then said that curly braces could (and pretty
will) be used instead.
Michael Chermside likes this design idea, but thinks the name for
``.cook()`` is not that great. Oren was going for a name that tied
into "raw". Michael suggested the name ``.sub()`` to build off of the
two PEPs already in existence covering string formatting (`PEP 215`_
and `PEP 292`_ ).
.. _re:
.. _PEP 215:
.. _PEP 292:
=====================
`Expect in python`__
=====================
__
Eric Raymond proposed adding pexpect_ to the stdlib when it reaches
version 1 (it is currently at 0.94). His thought was that having
functionality like Expect_ would be a boon for Python and use for
system administration. Eric said he had been using the module and
had no problems with it (Prabhu Ramachandran also said it had worked
for him).
David Ascher said that he would like to see a more abstract API to
allow it work for things other than character streams. He also would
like to see something work better on Windows. Eric said that he would
not want to hold up this for hopes of getting something better since
it already works well for what it does.
But it appears that the creator of pexpect is more than willing to
help maintain the module if it makes it into the stdlib.
Zach Weinberg said that he would be willing to put some work into
making the pty_ module more portable since pexpect does its thing
using pty.
.. _pexpect:
.. _Expect:
.. _pty:
===================================
`PEP 288: Generator Attributes`__
===================================
__
Raymond Hettinger has revised `PEP 288`_ with a new proposal on how to
pass things into a generator that has already started. He has asked
for comments on the changes, so let him know what you think.
.. _PEP 288:
===============================================
`PyMem_MALLOC (was [Python-Dev] Snake farm)`__
===============================================
__
Continuation of
There was a possible issue with ``PyMem_MALLOC()`` that Marc Recht had
discovered on FreeBSD. It eventually was tracked down to
FreeBSD-CURRENT's implementation of ``malloc()``: ``malloc(0)`` always
return 0x800. M.A. Lemburg suggested changing a test in the configure
script to try to catch when a platform returned an address for
``malloc(0)`` and treat it just like when it would return ``NULL``
(``NULL`` can't be blindly returned since that would signal a memory
error; returning ``NULL`` in a C extension signals an error). Marc
came back with news that C99 says that this is legitimate behavior for
``malloc()`` so this could possibly affect other platforms.
Marc suggested that ``PyMem_MALLOC()`` just be redefined to ``n ?
malloc(n) : NULL``. Problem is that the ``NULL`` issue mentioned
above comes into play with this solution. Tim Peters suggested either
``malloc(n || 1)`` or ``malloc(n ? n : 1)`` (the former being a Python
idiom that doesn't cut it in C). he does not want to mess with the
configure scripts since they have "proven itself too brittle too many
times". Tim wanted a way to prevent ever calling the function with 0,
but Guido couldn't see any way of doing that without an extra jump.
The committed solution is ``malloc((n) ? (n) : 1)``. Easier to just
waste one byte then have to deal with the special casing of passing 0.
The extra test was not really a worry since no measurable performance
reported by Tim. Besides, Tim pointed out "this is ideal for a
conditional-move instruction, and more architectures are growing
that".
====================================================
`Half-baked proposal: * (and **?) in assignments`__
====================================================
__
Gareth McCaughan suggested cutting down one of the separations between
parameter passing and assignment by allowing assignment to use
arbitrary argument lists::
>>> a,b,*c = 1,2,3,4,5 # c == (3, 4, 5)
>>> year, month, day, *dummy = time.localtime()
I argued that I didn't like the slightly cluttered look on the
left-hand side (LHS) of the assignment. Martin v. Loewis and I
basically ended up saying we wanted to keep assignments clear and
concise and that this would not help to keep that. Steve Holden
basically ended up agreeing.
Brian Quinlin, Patrick O'Brien, Nathan Clegg and Timothy Delany liked
the idea. The biggest argument in support was that it would allow for
a more functional programming style (and that obviously can be good or
bad depending on your P.O.V.; I say bad =)::
>>> car,*cdr = [head, t1, t2, t3] # car == head, cdr == (t1, t2, t3)
In case you don't have functional programming (especially Lisp/Scheme)
experience, the basic data structure in Lisp-like language is a list
and the most common way to manipulate those lists is with the
functions ``car`` and ``cdr``. ``car`` returns the "head", or front,
of the list; ``cdr`` returns the "tail", or everything but the head,
of the list. This allows for simple recursion since you just pass the
``cdr`` of a list on the recursive call after having dealt with the
head of the list.
There was also the suggestion of allowing the arbitrary assignment
variable to be anywhere in the list of assignment variables::
>>> a,*b,c = 1,2,3,4,5 # a == 1, b == (2, 3, 4), c == 5
To prove that this was not really needed I wrote a function that took
in an iterable and the number of variables to assign to and then
returned the proper number iterations on the iterator and then the
iterator as the last thing returned. Alex Martelli of course improved
upon it (and also continued to correct my slightly incorrect
statements)::
def peel(iterable, arg_cnt=1):
"""Return ``arg_cnt`` values from iterator of ``iterable`` and then
the iterator itself."""
iterator = iter(iterable)
for num in xrange(arg_cnt):
yield iterator.next()
yield iterator
The idea of a module for the stdlib containing iterator helper
functions was suggested by Alex. One is in progress by Raymond
Hettinger.
Armin Rigo suggested having iterators become a type. That was quickly
shot down, although having the suggested iterator helper module
contain a class that could be subclassed by iterators was received
with positive comments.
The thread ended very quickly after Guido said that he didn't think
"that there's a sufficient need to add new syntax".
===================================
`from tuples to immutable dicts`__
===================================
__
Armin Rigo said that he would like to have an immutable type that
acted like a dictionary; basically like a struct from C. Martin v.
Loewis agreed on the need, but opposed the idea of adding another
built-in type or syntax for such a type; that left something for the
stdlib. Martin suggested something like::
>>> struct_seq(name, doc, n_in_sequence, (fields))
where ``field`` is a bunch of (name, doc) tuples. What would be
returned would be a "thing [that] would be similar to os.stat_result:
you [can] call it with the mandatory fields in sequence, and can call
it with the optional fields by keyword argument".
Armin didn't like it since it went against his initial proposal "which
was to have a lightweight and declaration-less way to build
structures". He basically ended up suggesting something along the
lines of tuples with keyword arguments. Martin didn't like it since
he didn't see a great use for it.
In the end Armin said to just drop the idea.
============================================
`urllib performance issue on FreeBSD 4.x`__
============================================
__
Andrew MacIntyre brought a thread on python-list to python-dev's
attention about urllib performance compared to wget (wget is used to
download web sites and files). Apparently the used socket is
unbuffered instead of using the system default (which was shown to be
almost as fast as wget). The question became why this was done.
The answer (thanks to Martin v. Loewis) was to prevent deadlock.
Apparently under HTTP 1.1 a server can keep a connection open while
waiting for the next command. If the connection was buffered it would
block until it read enough to fill the buffer which may never come.
Frederik Lundh suggested that a subclass or option be available that
allowed the choosing of unbuffered or not. Andrew said he would put
it on his todo list.
=====================================
`test failures on Debian unstable`__
=====================================
__
Failures on the build of Debian's unstable version of Python led to a
discussion about how modules are skipped in the testing suite.
`Lib/test/regrtest.py`_ keeps a list of tests that are expected to be
skipped on various platforms. Martin v. Loewis doesn't like it
because tests such as for the bz2 module are attempted regardless of
whether the bz2 library is even installed and yet it is expected to
succeed on Linux. Martin summarized that "For many of the tests that
are somtimes skipped, knowing the system does not tell you whether the
test will should rightfully be skipped, on that system" since tests
are skipped often because a module was not there that needed to be
imported for the test.
Tim Peters, on the other hand, likes it. Since he maintains the
Windows distribution from PythonLabs he likes it since it lets him
know when new things have been added to Python and might need to be
excluded from the Windows distro. Neil (who pointed out the Debian
problems) was able to recognize that the tests that failed were meant
to pass under Linux. Tim admitted he only cared about keeping the
mechanism for Windows; he could care less if it is removed for Linux.
Patrick O'Brien chimed in (with Aahz supporting) that the feature is
handy since you can easily find out libraries you are missing that you
could potentially install.
Guido stepped in and suggested setting up a mechanism that would allow
an external table in a file to be used when present instead of the
default list of tests to skip. Don't think anyone has stepped up to
implement this.
.. _Lib/test/regrtest.py:
===================================================================
`Currently baking idea for dict.sequpdate(iterable, value=True)`__
===================================================================
__
Raymond Hettinger presented "a write-up for a proposed dictionary
update method". It basically took an iterable and added keys based on
the values returned by the iterator with a value as passed in and used
for all new keys. The rationale was to have a fast way to be able to
do membership testing using dict's ``__contains__`` or removing
duplicates by creating a dict and then outputting the keys using the
aptly named ``.keys()``.
Previous objecctions to something like this were about the dict
constructor and the ``sets`` module. The ones about the constructor
are dealt with by making this a method. The latter was argued against
by saying that the ``sets`` module is slow. Frederik Lundh brought up
that we really don't need multiple ways of doing the same thing. Just
van Rossum agreed and said this killed the idea for him. Guido chimed
in and said that the ``sets`` module was to help solidify the sets API
so that at some point it could be coded in C.
To address the speed complaint Guido suggested limiting the ``sets``
module initially to make it faster so that the type won't be held back
or unutilized because of its speed. Tim Peters spoke up, though, and
said that the spambayes_ project used ``sets`` and he didn't have any
complaints. But when major membership testing was needed a dict was
used. And Tim pointed out that in order for any C sets code to be
fast it would have to directly use dict's C ``__contains__`` code.
What this method should return was brought up by Just. Some thought
``None`` since ``.update()`` returns that. Others said ``True``.
Guido said ``None`` since ``True`` should only be used when something
is explicitly true.
Making it a class method was also suggested by Just as an easy way to
make it like a constructor. Raymond agreed and changed his proprosal
as well as to have the method be named ``.fromseq()``. But then
Walter Dorwald said ``.fromkeyseq()`` should be used since there "is
another constructor that creates the dict from a sequence of items".
Guido voted +1 on that idea.
.. _spambayes:
======================================
`Re: release22-maint branch broken`__
======================================
__
Tim Rice discovered that trying to build Python from a directory other
then where the source was did not work for the Python 2.2.* CVS. It
was all eventually solved and fixed in the CVS branch. I am
mentioning it here in case someone reading this had a similar issue.
================================
`Dictionary evaluation order`__
================================
__
Gustavo Niemeyer asked about how to handle code like ``{f1():f2(),
f3(): f4()}`` and its execution order as pointed out by `bug #448679`_
. As it stood it evaluated in the order of f2, f1, f4, f3.
Apparently Guido once upon a time considered this a bug.
But Guido mentioned that left-to-right evaluation is not always wanted
since ``a = {}; a[f1()] = f2()`` would want f2 to evaluate first. He
asked what Jython did.
Finn Bock said that Jython went f1, f2, f3, f4. In that case Guido
didn't see any reason to fix it. But Tim Peters brought up the point
that the bug was more about the lack of specifics on this in the
documentation. Gustavo said he would make the code fix along with
patches to the docs.
.. _bug #448679:
===========================
`int/long FutureWarning`__
===========================
__
Mark Hammond asked how the upcoming change in Python 2.4 of hex/oct
constants will affect his C extension code and something like
``PyArg_ParseTuple()`` (this function takes arguments passed to
something and breaks it up into its individual parts since all
arguments are passed as tuples in C code). In case you don't know
about the warnings, Python 2.3 warns you that code like ``SOMETHING =
0x80000000`` could have a different meaning in Python 2.4; most likely
it will be treated as a positive long. You can currently get rid of
the warnings by changing the constant into a long by tacking on a
``L`` to the end of the number.
Martin v. Loewis that if Mark appended the ``L`` to his constants that
it would not work for an ``i`` argument for ``PyArg_ParseTuple()``.
But Guido stepped up and said that there will be no issue since Python
will be changed so that Mark's code will accept the constant as a
positive long. This caused Guido to wonder if the warning could be
changed to some other warning that is not normally printed out.
Guido then mentioned that he has "long promised a set of new format
codes for PyArg_ParseTuple() to specify taking the lower N bits (for N
in 8, 16, 32, 64) and throwing the rest away, without range checks".
"If
someone else can get to this first, that would be great". So someone
be nice to Guido and do this for him. =)
Either way no specific resolution has been reached. As of right now
you can just live with the warnings, supress the warnings, or change
your constants to longs and hope you are not passing into a C
extension function that wants an int.
==========================================
`assigning to new-style-class.__name__`__
==========================================
__
Michael Hudson has been working on `patch #635933`_ to allow for
assignment to ``__name__`` and ``__bases__`` for new-style classes
(this was all so that ``__name__`` would handle nested classes
properly to allow for proper pickling; that thread was called
`metaclass insanity`_ ). He ran into a slight issue with dealing with
assigning to ``__name__``. To get it working, Michael wanted to treat
heap and non-heap types differently. For non-heap types Michael
wanted to "everything in tp_name up to the first dot is __module__,
the rest is __name__". For non-heap types, he wanted to have
``__module__`` as "always __dict__['__module__'], __name__ is always
tp_name (or rather ((etype*)type)->name)". And as for the issue of if
someone is crazy enough to delete the dict key of ``__module__``,
Michael said Python wouldn't crash but you probably would not like the
outcome of running code. =)
Guido responded saying that Michael's proposal was acceptable.
But then there was an issue with ``.mro()`` after the bases had been
rearranged. Michael worried about what to do when there was a
conflict down the intheritence tree. He thought reverting back to the
way things were if there was an issue was best. This would require
keeping around copies of the previous states until the changes
propogated all the way through.
Samuele Pedroni stepped in to try to answer this question (Samuele
rewrote the MRO code recently and is directly mentioned in `C3
implementation`_ ). He came up with a possible case where there could
be a possible order disagreement if two of the bases of a class had
the same bases but one had the order swapped compared to the other (so
C has bases of (A, B) and D has bases of (A, B) as well and E had
bases (C, D); if C's bases became (B, A), E now has an order
disagreement). He suggested that "the mros of the subclasses should
be computed lazily when needed (e.g. on the first - after the changes
- dispatch), although this may produce inconsistences and errors at
odd times".
Michael showed that his solution would catch the problem. But he did
not like the idea of lazily evaluating; he wanted a more restrictive
solution since this is a new thing. Michael stated that what he
wanted this for was to "to swap out one class for another -- making
instances of the old class instances of the new class, which was
possible and making subclasses of the old subclasses of the new, which
wasn't". It also turned out neither APL nor Dylan allow this kind of
thing so Michael is breaking new ground.
Samuele asked about when the classes had solid bases (i.e., only a
single superclass such as ``object``). Michael said it would handled
with no problem.
.. _C3 implementation:
.. _patch #635933:
.. _metaclass insanity:
=====================
`Classmethod Help`__
=====================
__
Raymond Hettinger emailed the list because Guido said that the few
people in the world who understand descriptors for C code are on the
list. The main reason I am mentioning the thread here, though, is
because Armin Rigo gave the answer that "There are METH_CLASS and
METH_STATIC flags that you can set in the tp_methods table".
You also learn, thanks to Guido, that you should only use
``PyErr_BadInternalCall()`` when you know that a "bad argment must
have been created by a broken piece of C code".
--
Linux is a registered trademark of Linus Torvalds
|
http://lwn.net/Articles/17027/
|
crawl-003
|
refinedweb
| 4,186
| 69.82
|
-
-
-
- Urgency:Normal
- Bug behavior facts:Regression
Description.
Issue Links
- incorporates
DERBY-4960 Race condition in FileContainer#allocCache when reopening RAFContainer after interrupt
- Closed
DERBY-4974 InterruptResilienceTest fails on Solaris with Sun VMs prior to 1.6
- Closed
DERBY-4982 Retrying after interrupts in store pops a bug in derbyall/storeall/storeunit/T_RawStoreFactory in some cases
- Closed
DERBY-5223 Thread's interrupted flag not always preserved after Derby returns from JDBC API call
- Closed
DERBY-5233 Interrupt of create table or index (i.e. a container) will throw XSDF1 under NIO - connection survives
- Closed
DERBY-5312 InterruptResilienceTest failed with ERROR 40XD1: Container was opened in read-only mode.
- Closed
DERBY-5325 Checkpoint fails with ClosedChannelException in InterruptResilienceTest
- Closed
DERBY-5152 Shutting down db, information that the thread received an interrupt will not be restored to thread's interrupt flag
- Closed
DERBY-5333 Intermittent assert failure in testInterruptShutdown: thread's interrupted flag lost after shutdown
- Closed
DERBY-4963 Revert to FileDescriptor#sync from FileChannel#force to improve interrupt resilience
- Closed
DERBY-4967 Handle interrupt received while waiting for database lock
- Closed
DERBY-4968 Let query stop execution if an interrupt is seen, at same time as we check the query timeout
- Closed
DERBY-5024 Document the behavior of interrupt handling.
- Closed
- is related to
DERBY-3746 java.sql.SQLException: The exception 'java.lang.NullPointerException' was thrown while evaluating an expression.
- Open
-
DERBY-4911 restoreIntrFlagIfSeen may throw ShutdownException causing confusing console stack trace at server shutdown
- Closed
Activity
- All
- Work Log
- History
- Activity
- Transitions
Yes, I agree, Knut. Just did it
Uploading an experimental patch which upon seeing the container channel interrupted/closed,
closes and reopens the container to allow completion of the I/O.
Using a modified Derby151Test, the trace on my box (OpenSolaris snv_148, Java 1.6) shows how
the RAFContainer4.java I/O code recovers. When an interrupt is detected (in the form of an interrupted channel),
the thread's interrupt flag is tucked away in a thread local variable for now, and the flag is reset, so the thread can continue and retry the I/O operation when the container has been resurrected.
The idea is that the thread local variable might be checked "higher up" somewhere, where throwing an exception would not make the database go down.
During this investigation, I have found numerous other locations at which an interrupt will make Derby go down, though, so RAFContainer4.java (or in deed NIO) is not the only weak spot we have.
Running the test on Windows, I see Derby choke on trying to switch log files, cf the enclosed derby.log file "derby-4741-nio-container-2.log" due to seeing a ChannelClosedException on the log file (NIO channel.force).
Uploading a modified version of the experimental patch, nio-container-2b, which also includes a standalone test I have been using to flush out effects of interrupts on threads..
Now, heading back to Solaris after having flushed out NIO issues on Windows, I see that Derby falls over when it gets interrupted
during transaction abort (XSTB0), as a result of receving an interrupt during a log flush wait(LogToFile.java:4048). I saw this using InterruptedTest in the patch. The test tries to reconnect (reboot), but eventually I can no longer get a connection, because I hit a NullPointerException in BaseDataFileFactory.java:639 (containerCache empty??). Cf enclosed xsbt0.log..
so far your approach seems fine to me, and I think will help a lot of customers. I was wondering if
you have a high level goal. Basically what should derby do when it encounters?.
Something to think about in the error throwing is the background thread. What should we do if
it encounters an interrupt. Throwing an error there might shutdown the db, i am not sure what it
does at top level with an error.
Hi Mike, thanks for looking at this!
> I was wondering if you have a high level
> goal. Basically what should derby do when it encounters an
> interrupt.
I started off merely trying to make the new IO pieces stand up as well
as the old I/O, but I guess my ambitions grew a bit as I found many
things could bring Derby down..
My thinking so far is that Derby should:
a) avoid having to shut down if a thread has been interrupted
b) throw something when it finds the thread has been interrupted,
preferably as soon as possible, but not before the code has arrived at
a "safe place", so we can avoid Derby shutting down.
>.
Agreed. So far I have been thinking of just using the connection level error 08000,
wrapping the original NIO channel exception, or InterruptedException.
This should make it clear what has happened, and unwrapping the exception would
show where Derby detected it.
> I think the error should not be database level, and with your retry
> on I/O and log it seems like we can avoid that.
That's what I am trying to achieve, yes.
> I am not sure if it should be session or statement level, I am
> leaning to it being session level, but would like to see a
> discussion. I know often users are doing the interrupt to stop a
> thread.
The existing code throws session level error 08000 already in many
places, and I felt it's OK to require that the user reconnect when she
has done something as drastic as interrupting the thread
> Ultimately do you plan on always reenabling the interrupt after
> retrying or getting to a safe place?
I am still pondering this question. I think that by the principle of
least surprise to the user, we should set the interrupted flag of the
thread again just before we throw the exception from the "safe place".
Note: the exisiting code does not resurrect the
thread's interrupted flag when it detects an interrupt of a wait and throws
StandardException.interrupt. (wait would have cleared the flag).
An imminent problem is where would the "safe place" be? It would be
nice to avoid having to check in all JDBC API methods before we
return if Derby has been interrupted during the API call, but I am not
yet sure if I am able to determine conclusively which API code paths
could lead to Derby being interrupted.. One approach would be to throw
as "soon as possible" from a "safe place" on the stack above the
method that saw the interrupt, but it may be hard to always determine
where that would be in all cases. I am open to suggestions here
The current experimental patch mostly doesn't throw yet (I didn't get
that far) - it just makes a note that an interrupt was detected. Nor
does it resurrect the interrupted flag when it does throw - since I
was still torn on this.
>.
Yes, I am trying to do exactly that, agreed.
I also would like interrupts on queries to be detected no later that
at the place where we check for query time-outs already,
cf. BasicNoPutResultSetImpl#checkCancellationFlag.
> Something to think about in the error throwing is the background
> thread. What should we do if it encounters an interrupt. Throwing an
> error there might shutdown the db, i am not sure what it does at top
> level with an error.
Right. A priori, I thought the most common use case would be user
threads getting interrupted, but I'll look into that. One approach
could be to shutdown, or possibly try to make it impervious and ignore
all interrupts..
Uploading a new version of the experimental patch, derby-4741-nio-container+log+waits+locks,
which
a) handles interrupts during lock wait
b) retries when LogToFile fails during call to switchLogFile#preAllocateNewLogFile's call to syncFile, which I also saw,
but there are probably more places where logging can fail
c) adds a "lock" argument to InterruptTest to test safe throws for a)
Thanks Dag. The proposed plan sounds good to me.
As to what to do with the interrupt status after a retry, I'd be happy as long as we always either fail or preserve the interrupt status. I don't have any strong opinions on whether or not we should set the interrupt flag when raising the exception. I see that the pre-NIO methods that may be interrupted (wait, sleep, join) will throw an exception and clear the interrupt status, whereas the interruptible NIO methods will throw an exception and set the interrupt status, so the precedence from the class library is ambiguous. I agree, though, that the user's intent is probably to stop the thread, and then preserving the interrupt status sounds reasonable in order to prevent that the thread just runs to the next blocking call and gets blocked there.
Thanks, Knut! I agree it's a bit weird that the JRE is a little schizophrenic about the interrupt flag. I think we should try to be consistent when we throw, no matter where/after which Java API call Derby detects it. If we do retain the interrupt flag, I think it adds to the argument for making the exception session-level, since the user would need to undertake some cleaning up anyway, or else the next Derby call would fail as well. Probably this would be the use case for connection pools. As to arguments for making the error statement level, I guess if one just wants to stop a run-away query, one would possibly prefer that just the statement failed. A thing to consider here is the new JDBC 4.1 method Connection#abort:
This would be the future portable way of stopping a run-away transaction. It will also close the the connection.
This patch passed regressions, for what it's worth. point.
Hi Lily, thanks for test driving the patches
Du you know if mailjdbc uses interrupts in any way? I'll try to run it myself, maybe some of the changes changed behavior even in the absence of interrupts. Btw, there are still many holes, I have found more places especially in the logging system that are vulnerable to
interrupts, so I am still building out the experimental patch.
Hi Dag,
There's some discussion about mailjdbc and interrupts on DERBY-3746. The comments there seem to indicate that the test sometimes interrupts the worker threads.
Hi Dag:
Thank you. I am so exciting to help out testing and hope I can do more. Like Knut said, mailjdbc interrupts on Browse.java and more detail on DERBY-3746 and
DERBY-4166, the portion of the code on Browse.java that call interrupt is:
//Checking whether Refresh thread is running after doing Browse work
//If Refresh is not running, interrupt the thread
if (ThreadUtils.isThreadRunning("Refresh Thread"))
else{ Refresh th = (Refresh) ThreadUtils .getThread("Refresh Thread"); th.interrupt(); }
Refresh thread and Brose thread are dealing with the same tables for mailjdbc application. I am also reading Derby151Test to see whether we should simplify the mailjdbc test to better fit testing this fix that will benefit a lot of customers. Thanks again. By the way, the read-only error on Browse thread and ArrayIndexOutOfBoundsException from backup thread is from running mailjdbc with embedded server..
Lily, I looked at derby.log: The stack trace you see first: "ERROR 40XD1: Container was opened in read-only mode." seems to happen
while Derby is opening the conglomerate in the normal fashion and finds for some reason that it (or the directory) is not writable. It is not obvious to me that
this has to do with the patch, but it is not impossible, I suppose, since the patch does touch RAFContainer(4), e.g. by reopening the container if the channel has been closed by interrupts. But this seems to be a normal open, not a reopen called from RAFContainer4 (which is not on the stack).
Cf. RAFContainer#run, action OPEN_CONTAINER_ACTION, ca line 1447.
I'll see if I can run the test myself and reproduced the error.
Attaching derby-4741-nio-container+log+waits+locks-2, which adds more interrupt recovery logic, mainly to LogToFile.java and LogAccessFile. With this version I have not yet been able to make crash the database (i.e. provoke a database level error) using the three run modes of InterruptedTest - default, i.e. write, read and lock, so we are gettting more resilient.
Only interrupted lock waits are added as new Derby exception cases yet, I'll start looking into where to throw more seriously now. Indeed, some existing cases where we did throw in LogToFile, don't throw in the current patch, we just take a note and retry.
Lily, I ran mailjdbc test with my latest patch on Windows Vista for about 20 hours; I saw deadlocks, but not the read-only container error.
I did see several mysterious lines in derby.log, e.g.
"not switching from an empty log file (870)"
similar to what you had in your derby.log. I have no experience with this test, so I don't know if this is normal for this test or a sign that something is wrong; I'll try to run the test without the patch and compare.
Re mailjdbc: It seems "not switching from an empty log file" in derby.log is normal for this test, at least I see it on trunk without the patch. see.
Uploading another experimental patch, derby-4741-nio-container+log+waits+locks+throws.
The change now is
- some further generalizing of recovery logic in RAFContainer4, the readPage logic was missing some stuff I had added for writePage
- introduced InterruptTest#throwIf, which is a helper method to check & reset the thread's interrupt status and throw an SQLException (08000 for now) if set.
- added throwIf next to Query timeout logic in BasicNoPutResultSetImpl#checkCancellationFlag
- added throwIf before all returns in impl/jdbc/*.java in methods which call (directly or indirectly) handleException(t), typically this pattern:
:
InterruptTest#throwIf()
return;
} catch (Throwable t) {
throw handleException(t);
This will make sure Derby throws if it ever did see an interrupt during operation, which was intercepted for safety and postponed till a "safe place". This is a "catch-all", though, and I'll look for other places closer to the
originating sites (container I/O, log I/O) so Derby could throw earlier.
For example, commit can now throw if we see an interrupt during writing to log, cf. call to throwIf in EmbedConnection#commit.
Currently all interrupts throw 08000 which is session level, and none yet set the thread's intr flag. I will go over all usages of 08000 and set the flag next if we agree that's the right thing to do. Note that Derby151Test fails now, but InterruptTest should work and report all interrupts Derby see (some interrupts happen while the test is in application code; this is called out in the test's results). Btw, InterruptTest is not yet a JUnit test..
The patch is getting a bit large and unwieldy now, but not to worry, the patch is just a proof of concept, I'll break it down into smaller pieces before any proposed commit. Rerunning regressions.
I see Lily would prefer statement level error, rather than session level. I am sticking to session level for now since that's what the exisiting 08000 currently is. I'll go over the remaining existing usages of 08000 which I didn't already replace with "InterruptStatus.setInterrupted" + retry logic. If all are ok to replace, we could probably choose to change the exception to statement level rather than session level. If not, it might be confusing to have two kinds of SQLExceptions for interrupts, with different severity...
Uploading the last patch again (derby-4741-nio-container+log+waits+locks+throws) - it had a small bug that broke LogSwitchFail.unit, fixed now
.
Thanks Dag for giving such details about each change. It definitely helps people like me to learn and understand more. The patch is getting big and complicated. However, I run mailjdbc again the latest derby-4741-nio-container+log+waits+locks+throws, the test run into Error ERROR 40001: A lock could not be obtained due to a deadlock. derby.log is attached for reference. Do we need InterruptException on synchronized (slaveRecoveryMonitor) in LogToFile.recover(...)? Will change interrupt exception to statement level rather than session level require more code changes? Such as code in impl/store/raw/xact/* I was just thinking statement level is more user friendly to application users.
Hi Lily,
thanks again for looking at this
> However, I run mailjdbc again the latest
> derby-4741-nio-container+log+waits+locks+throws, the test run into
> Error ERROR 40001: A lock could not be obtained due to a
> deadlock. derby.log is attached for reference.
Yes, I saw that such lock errors too after about 18 hours of so. I am
not yet sure they have anything to do with the patch changes, but I
can't rule it out. I don't know the test app well enough. If you have
any insight here which would indicate that locks should not occur
under normal operation, what would that be? We could try to run the
patch without the changes I made to ActiveLock, ConcurrentLockSet and
LockSet, and see if the changes there have something to do with any
change of behaviour..
>.
Generally I have just been concentrating on "normal operation" yet, so
far I haven't yet looked into things like replication, backup,
export/import, or even LOB/CLOB streams yet. I suspect there may be
issues with interrupts happening during I/O in those areas as well.
> Will change interrupt exception to statement
> level rather than session level require more code changes? Such as
> code in impl/store/raw/xact/*
I don't know that for sure, but I suspected it might, the cleanup on
session termination just seemed safer and in line with what we already did
for interrupt exceptions. More investigation needed.
> I was just thinking statement level is more user friendly to
> application users.
Yes, I see that point. If we decide that's the way we would ultimately
like to go, I think I will still defer that to a next increment (maybe
a new JIRA issue?) of this work just to keep things simpler for now.
Running a micro benchmark to test the effect for adding InterruptStatus.throwIf to the APIs
were a bit inconclusive. With the latest patch, using the attached MicroAPITest.java (ca 6-7 runs), I saw a ca 2.5 & degradation of performance with just calls to ResultSet.next for a database that fits in memory.
However, just adding the InterruptStatus.throwIf calls to the API without the rest of the patch seemed to have no significant effect, so perhaps there are other parts of the patch that had made the operation somewhat slower, I'll try to incrementally remove parts of the patch and see what I find.
I've also tried the micro benchmark, but got somewhat different results. In 20 runs with a clean trunk and 20 runs with the derby-4741-nio-container+log+waits+locks+throws.diff patch in random order, clean trunk was on average 8.5% faster than the patched version (3.64 s/query vs 3.95 s/query).
I ran the experiment with insane jars on OpenSolaris 2010.05 snv_134b and Java 1.6.0_18, and I had upped derby.storage.pageCacheSize to 12500.
Thanks for the important finding. The result is hard on issues to keep Derby stand out from other Java database. I humbly believe Derby will keep on shining if performance can keep on improving. Do you have any suggestion in turn of fixing thread interrupts and keep performance no less than 3% slower than current clean trunk?
Oops... Clean trunk wasn't 8.5% faster than the patched version. It was 7.8% faster. What I should have said, was that the patched version was 8.5% slower than clean trunk.
I ran the micro benchmark through a profiler, but I didn't see anything there to explain a ~8% degradation. I did see more time spent in ThreadLocal.get() (no surprise there...), but only enough to explain one or two percent, roughly what Dag saw. I'll try to dig a little more.
Thanks for doing more measurements, Knut! It seems that even in the best case, the movePostion operation is negatively impacted with 1-2% due to the ThreadLocal access, which is not desirable.
Knut mentioned that ContextService is already based on a ThreadLocal. I checked around a bit and found that we might be able to get rid of the InterruptStatus thread local check in the API methods in this way:
If we were able to retrieve the lcc at the point where we detect the interrupts and save this fact in the lcc at that time, the cost of accessing a ThreadLocal variable would not be incurred unless AN INTERRUPT ACTUALLY HAPPENED.
In the API methods, lcc is already available, and checking a boolean flag in the lcc instead of calling InterruptStatus#throwIf (which accesses a thread local) would be much cheaper. I see we already sometimes do dig out the lcc in store level code, e.g. in store.access.DiskHashtable, in this way:
LanguageConnectionContext lcc = (LanguageConnectionContext)
ContextService.getContextOrNull( // this call accesses a ThreadLocal
LanguageConnectionContext.CONTEXT_ID);
I'll look into this approach a bit.
The approach seems to work. This should take care of the performance worries for using InterruptStatus#throwIf in API methods.
Sometimes there is no lcc, e.g when creating a new database; we could then fall back on the dedicated thread local variable, cf. during EmbedConnection constructor's call to createDatabase.
Another note: undo is still vulnerable, e.g. an interrupt during rollback, usage of StorageRandomAccessFile in cf. Scan.java, cf.
------------ BEGIN SHUTDOWN ERROR STACK -------------
ERROR XSLA3: Log Corrupted, has invalid data in the log stream.
at org.apache.derby.iapi.error.StandardException.newException(StandardException.java:279)
at org.apache.derby.impl.store.raw.log.Scan.getNextRecord(Scan.java:216)
at org.apache.derby.impl.store.raw.log.FileLogger.undo(FileLogger.java:939)
at org.apache.derby.impl.store.raw.xact.Xact.abort(Xact.java:949)
at org.apache.derby.impl.store.raw.xact.XactContext.cleanupOnError(XactContext.java:119)
at org.apache.derby.iapi.services.context.ContextManager.cleanupOnError(ContextManager.java:333)
at org.apache.derby.impl.jdbc.TransactionResourceImpl.cleanupOnError(TransactionResourceImpl.java:419)
at org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(TransactionResourceImpl.java:337)
at org.apache.derby.impl.jdbc.EmbedConnection.handleException(EmbedConnection.java:2277)
at org.apache.derby.impl.jdbc.ConnectionChild.handleException(ConnectionChild.java:81)
at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(EmbedStatement.java:1325)
at org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(EmbedPreparedStatement.java:1683)
at org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeUpdate(EmbedPreparedStatement.java:305)
at InterruptTest$WorkerThread.run(InterruptTest.java:263)
Caused by: java.io.InterruptedIOException
at java.io.RandomAccessFile.read(Native Method)
at java.io.RandomAccessFile.readInt(RandomAccessFile.java:721)
at java.io.RandomAccessFile.readLong(RandomAccessFile.java:758)
at org.apache.derby.impl.store.raw.log.Scan.getNextRecordBackward(Scan.java:394)
at org.apache.derby.impl.store.raw.log.Scan.getNextRecord(Scan.java:204)
(roll-back happens here due to the test trying to insert a duplicate after a commit has been interrupted)
And we are vulnerable during (re)boot:
java.sql.SQLException: Failed to start database 'interrupttest' with class loader sun.misc.Launcher$AppClassLoader@2bbd86, see the next exception for details.
:
Caused by: java.sql.SQLException: Failed to start database 'interrupttest' with class loader sun.misc.Launcher$AppClassLoader@2bbd86, see the next exception for details.
:
Caused by: java.sql.SQLException: Java exception: ': java.io.InterruptedIOException'.
:
Caused by: java.io.InterruptedIOException
at java.io.RandomAccessFile.readBytes(Native Method)
at java.io.RandomAccessFile.read(RandomAccessFile.java:322)
at java.io.RandomAccessFile.readFully(RandomAccessFile.java:381)
at java.io.RandomAccessFile.readFully(RandomAccessFile.java:361)
at org.apache.derby.impl.store.raw.log.LogToFile.readControlFile(LogToFile.java:2693)
at org.apache.derby.impl.store.raw.log.LogToFile.boot(LogToFile.java:3398).raw.data.BaseDataFileFactory.bootLogFactory(BaseDataFileFactory.java:1747)
at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.setRawStoreFactory(BaseDataFileFactory.java:1235)
at org.apache.derby.impl.store.raw.RawStore.boot(RawStore.java:223).access.RAMAccessManager.boot(RAMAccessManager.java:1019).db.BasicDatabase.bootStore(BasicDatabase.java:760)
at org.apache.derby.impl.db.BasicDatabase.boot(BasicDatabase.java:193)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(BaseMonitor.java:2020)
at org.apache.derby.impl.services.monitor.TopService.bootModule(TopService.java:333)
at org.apache.derby.impl.services.monitor.BaseMonitor.bootService(BaseMonitor.java:1857)
at org.apache.derby.impl.services.monitor.BaseMonitor.startProviderService(BaseMonitor.java:1723)
at org.apache.derby.impl.services.monitor.BaseMonitor.findProviderAndStartService(BaseMonitor.java:1601)
at org.apache.derby.impl.services.monitor.BaseMonitor.startPersistentService(BaseMonitor.java:1020)
at org.apache.derby.iapi.services.monitor.Monitor.startPersistentService(Monitor.java:550)
at org.apache.derby.impl.jdbc.EmbedConnection.bootDatabase(EmbedConnection.java:2679)
I feel pretty confident the main approach will improve things by now, so I'll upload a final version of the experimental patch, and the start producing incremental patches for commit roughly in the following order:
a) hooks in the APIs to resurrect interrupt flags before we return to the user's app on the basis of info collected during operation, the new util class InterruptStatus, which is a collection of methods to save away and resurrect interrupt flags, and throw an interrupt SQLexception. I intend to not throw any exception if the API method ran to completion, just resurrect the flag.
b) the modified RAFContainer4 stuff for reading and writing db cache pages safely with NIO.
c) the modified DirRandomAccessFile4 stuff + log retries for safe operation of log writing
d) stop execution if intr seen within a batch, when checking query timeout, and when seeing intr while waiting for locks
e) make undo safe
f) time permitting, make boot and recovery interrupt safe.
Please let me know if there any objections or suggestions to this plan! Whether all this gets ready for 10.7 is a possible issue, but hopefully we should not behave worse the before at any step...
Note to self: I have found a problem with the interrupt recovery of
RAFContainer4. Its call to openContainer needs to be protected by the
monitor on FileContainer#allocCache, because opening a container
evetually leads to a call on AllocationCache#reset. AllocCache javadoc
states that the the callers need to synchronize themselves since it is
itself not MT safe.
Threads inside RAFContainer4#{readPage, writePage}
do not necessarily
own this monitor when recovery is attempted.
I did once see a race condition due to this. In the race condition, a
thread was trying to write to a new page and got a array out of bounds
exception inside AllocationCache.validate (numExtents was suddenly back to 0)
because another thread was doing interrupt recovery by calling
RAFContainer4#recoverContainerAfterInterrupt ->
openContainer -> ... -> AllocationCache#reset (unprotected).
[edit add]:
Simply enveloping recoverContainerAfterInterrupt's call to openContainer in synchronized(allocCache) won't work: can lead to deadlock.
I ran MicroAPITest with derby-4741-all+lenient+resurrect.diff (20 runs with each configuration, insane jars, pageCacheSize=12500). Now I only see a 1% degradation with the patch (p-value=0.07, according to the student t calculator at), so that definitely looks like a good improvement from the previous patch. I also modified the test so that it reused existing test data instead of creating it on every run. Then I didn't see any degradation. In fact, the results with the patch were 0.5% better than trunk when I ran the test that way.
I also saw something similar with the previous patch. I saw an 8% degradation with the unmodified test, but the degradation was only about 2% with the modified test. This is also consistent with the findings Dag posted in the comment dated 15/Oct/10 12:06 PM, where he saw that the full patch gave a 2.5% degradation, whereas if he only applied the parts of the patch that were actually exercised during the data collection phase of the test, he didn't see any degradation.
I don't know why the changes in the test setup code alters the result this way. The part of the test where we collect results should exercise the exact same code path with the two variants of the test. This reminds me of the effects we saw in
DERBY-4233, which were attributed to JIT at that time. I think the theory at that time was something like this: The just-in-time compiler collects statistics before it compiles the code and uses the statistics to optimize the generated native code. The more time we spend in the test setup code, the more the statistics will be biased towards the setup code. For this test, that could mean that the JIT-compiled native code is optimized for the insert code path, whereas we're really only interested in the select code path in the test. Furthermore, since the patch changes code on the insert code path, the collected statistics and the chosen optimizations may change, and that may ultimately affect how the select code is optimized, even if the select code path barely has been touched by the patch. ever!!!.. See also its Javadoc.
-.
Hi Dag:
Thank you so much for the write out. All a, b, c, d points are very clear and straight forward. Personally, I like the fact we are checking interrupt at executeBatch, executeQuery, BasicNoPutResultSetImpl(same as timeout) and waiting for lock area. Thank you for add the synchronized (slaveRecoveryMonitor) and adding all the necessary release notes information.
I apply the derby-4741-a-01-api-interruptstatus. All the suites.all passed and timing for MicroAPITest is close to clean trunk. It also passed Derby151Test with interrupt check. Mailjdbc is still having deadlock issue. However, like you said, it might or might not cause by the new change. I notice some of the interrupt code is in slight different places in Embed*.java with local initial null value. And, some of interrupt handling code are not in this patch than the previous patch. I am assuming those code are handling machinery of InterruptStatus that save interrupts and it will come in later patch.
I view this patch as it will benefit a lot of customers and love to help out if I can. Thank you so much for working so hard on this.
Hi Lily, thanks for test driving the patch
I really appreciate your help looking at this work. Having another set of eyes on this is good, the change are a bit cross cutting and affect much existing code, so it's good to have someone double checking the changes. Two comments:
- if the mailjdbc test still deadlocks, I doubt it can be due to this patch, since it doesn't really change any behavior, it just installs the machinery for the behavior changes to come in later patches, as you presumed.
- the difference is EmbedBlob with local initial null is just some cruft from an experiment I did with trying to place restoreIntrFlagIfSeen in a finally block. This didn't work out since, error handling may close the connection and with it the lcc, so the check would happen too late. (The current method is to check before return and in the error handling code itself). I'll revert that change, thanks for noticing.
My main concern with this patch currently is to verify that I have found all the ways control can return to the user app after Derby code has had control, and possibly set the interrupt status flag. A case in point is the Blob methods that don't require a connection, e.g. EmbedBlob#getBytes if the lob is materialized, we call control.read: if we see an interrupt inside the read, the flag would get stored in a thread local variable, since there is no lcc, so I'll I need to add a call to no-args version of restoreIntrFlagIfSeen() there. EmbedClob needs analysis, too.
Uploading derby-4741-a-02-api-interruptstatus, an improved version of
a-01.
I went over the usages of restoreIntrFlagIfSeen in the API and
reevaluated where it is possible to supply the lcc and where it is not
safe: the intention is that if we stored the interrupt status flag in
a lcc we should be recover it from there before returning to the user
app and, similarly, if we stored the interrupt status flag in a thread
local variable because an lcc was not available, we should recover it
from there. It turns out it is not always obvious to determine where to
look in the API methods.
API methods vary with repect to whether they:
a) synchronize on the connection or not, cf. possible bugs
see DERBY-4129, even when accessing store.
b) call setupContextStack or not (this is what lets us find the
lcc down in store using ContextService.getContextOrNull)
c) clean up when errors occur by calling handleInterrupt(t), cf my
comment on DERBY-4129, e.g. EmbedClob. The cleanup can lead to
a connection closing if severity is high, setting its lcc to
null.
d) even if an API method doesn't call setupContextStack, it may be
called indirectly from a context that does set it up, cf.
part of a trigger on an insert.
When a connection (or database) is being closed down, we need to be
careful so that we catch the lcc while it is still available. When
cleaning up errors in TransactionResourceImpl#handleException we do
not directly know if an lcc is available or not.
The upshot of all this is that unless we are sure we have a valid lcc
(i.e. we see statically that setupContextStack has been called), we
instead call restoreIntrFlagIfSeen without an lcc argument. The
zero-arg variant calls getContextOrNull to see if a lcc is available
for the thread, falling back to the thread local if not. So, in
effect, the lcc variant is an optimization, but it does cover the
methods for which performance could be an issue, I think.
The new patch covers LOB ands CLOB as well, and is ready for review.
Regressions ran ok.
Uploading version a-03, minor and clerical changes only relative to a-02.
When running MicroAPITest against a-03 patch, it is 45-48 seconds vs clean trunk 27-28 second. I noticed it is not using lcc but the earlier slower approach. Are you seeing the same slow windows performance again a-03 patch.
Thanks for test driving it, Lily. The new patch does use the lcc if available, it just falls back on the TL approach if not, so the performance drop was unexpected to me. I'll have a look, thanks for noticing.
Lily, did you with a sane or insane build? I see a large difference also (Solaris though) with sane (due to an expensive assert), but with insane is it very small (~<1%).
Hi Dag: That is interesting. I was using sane build. Shouldn't sane build have similar performance as insane or they are usually having difference?.
Hi Dag,
I went through the a-03-api patch, and I couldn't spot anything that
you've missed.
There were quite a number of places to check the interrupt
status. More than what I had expected. But I cannot think of a better
place to short-circuit it, so...? That may make the code more contained, but
perhaps the LCC isn't easily available there?
Apart from that, I only have some minor comments to the code in the
InterruptStatus class. Very minor, so feel free to ignore.
- throwIf: Unnecessary return statement.
- stackTrace: The initialValue() override does the same as the default
implementation. So by just using a vanilla ThreadLocal object, we'd
get the exact same behaviour, and one less class in derby.jar +
permgen. (If the footprint issue is important, the same might be
said for receivedInterruptDuringIO if we change its usage from a
TRUE/FALSE check to a null/non-null check. Actually, the presence of
a stack trace is probably a good enough indicator in itself.)
- Instead of creating an exception, fetching its stack trace and
storing the trace, perhaps it would be easier just to store the
exception? Then throwIf() could throw the stored exception instead
of creating a new one and modifying its stack trace.
Knut is right, that was the expensive assert I mentioned before (in sane builds). Since this is a micro benchmark that mainly measures the CPU neeeded to execute ResultSet.next when data is cached in memory, the effect of the assert shows up heavily. Running a profiling I saw the string concatenation there being dominant. No, I did not notice the regression test become slower, but if the turns out to be an issue, it is easy enough to comment out the asset. For now, I'll change the assert code to just call getContextOrNull once.
Thanks for looking at the patch, Knut!
>?
I did try to put the call into the finally,although not into restoreContextStack. I found that didn't always work, since during error handling before we get to the finally block, calls to handleException(throwable) will depending on severity, potentially take down the connection (and database), causing us to lose the lcc. Hence I had to move it back to just before normal return, and use the no-args variant of restoreIntrFlagIfSeen handling inside the error handling code (cf changes in TransactionResourceImpl#handleException).
> - throwIf: Unnecessary return statement.
Agreed, will fix that
> - stackTrace: The initialValue() override does the same as the default implementation. So by just using a vanilla ThreadLocal object, we'd get the exact same behaviour, and one less class in derby.jar + permgen.
Agreed.
> (If the footprint issue is important, the same might be said for receivedInterruptDuringIO if we change its usage from a TRUE/FALSE check to a null/non-null check. Actually, the presence of a stack trace is probably a good enough indicator in itself.)
Yes and yes. Originally I used the stacktrace just for debugging with sane, I think.
> - Instead of creating an exception, fetching its stack trace and storing the trace, perhaps it would be easier just to store the exception? Then throwIf() could throw the stored exception instead of creating a new one and modifying its stack trace.
That's good simplication, yes.
Uploading a revised patch, derby-4741-a-04-api-interruptstatus, which takes care of the comments. hopefully. Rerunning regressions.
Regressions ran ok. Will commit this version soon, if no misgivings emerge.
Thanks for the changes and the explanations, Dag. I have no further comments to the a-04-api patch.
One observation: After looking at the changes in EmbedBlob.getBytes(long,int) and EmbedBlob.position(), I understand why some people advocate that all methods should have a single exit point.
I test drive a-04-api patch as well. The sane MicroAPITest result is very good. I got result that is 5s - 7s. The insane result is similar to a-03-api which is around 45s--52s vs 27s-28s on clean trunk. However, like we discussed previous for MicroAPITest benchmark is only focus on CPU result and the slowdown is mostly on ASSERT. With so many things to take care of with 10.7 release. +1 to commit.
Committed derby-4741-a-04-api-interruptstatus as svn 1030630.
Uploading patch derby-4741-b-01-nio. This patch contains changes to
FileContainer/RAFContainer/RAFContainer4 to allow page IO to recover
from interrupts seen in RAFContainer4 (the NIO[1] version
specialization of RAFContainer). Additionally, some waits are changed
to retry after interrupts (yes, there are more of those in other
classes, that's for a later patch, but since I was in there anyway..)
The main thrust of the patch is in RAFContainer4. Upon seeing
exceptions from IO (readPage/writePage), a thread will determine if it
is
a) the thread that caused the channel to beclome closed, or
b) it suffered an exceptions because another thread caused the
channel to beclome closed.
If a), the thread will recover by reopening the container before
reattempting IO, cf. the method recoverContainerAfterInterrupt. If b)
the thread will yield, wait and retry until the container has been
recovered, or a minute has passed. After a minute, we give up and
throw FILE_IO_INTERRUPTED. I chose a minute somewhat arbitrarily, it
is hopefully sufficient
.
The recovery thread and other waiting threads normally synchronize the
operations via variables protected by the channelCleanupMonitor
monitor (but see use of volatile and associated comments).
The retry logic happens in one of three places, in increasing
closeness to RAFContainer4:
a) if the thread owns the monitor on allocCache and it is not the
one that is doing recovery, it will back up to FileContainer
before retrying the IO, since it has to release the lock on
allocCache, because that monitor is needed by the thread doing
recovery. Cf. changes in FileContainer. If the thread holds
allocCache, it goes into stealth mode in readPage/WritePage:
this means that the recovery thread doesn't see it. We can't
let a stealth mode thread grab channelCleanupMonitor, as this
could cause a dead-lock. In c) the recovery thread keeps track
of other threads, waking them up when recovery is done.
b) if the thread owns the monitor on "this", again the thread goes
into stealth mode. If it is not the one to clean up, it will
back up to RAFContainer#clean's loop, since it has to release
the lock on "this", because that monitor is also needed by the
thread doing recovery. This only ever happens for readPage (not
writePage), cf. call to getEmbryonicPage in WriteRAFHeader
called from RAFContainer#clean.
c) in other cases, the thread will call awaitRestoreChannel before
reattempting IO.
The logic of RAFContainer4#getEmbryonicPage has been folded into
readPage in order for it to be covered by the interrupt treatement.
The test Derby151Test has been removed, since it is no longer
relevant. A new test, InterruptResilienceTest, fails without the
patch, but should work with the patch in place. It interrupts the
single app thread before doing IO, which will trip NIO and cause
recovery. Even though we have only one app thread, the test still
revealed concurrency issues during the development of this patch,
since RawStoreThread will also do IO on the container.
A note on the implementation: Sun Java NIO code (including the
latest 1.6) has a bug which are worked around by the patch in two
places, cf. code comments:
- readFull/writeFull: if a thread has been interrupted,
occasionally it closes the channel but does not throw,
cf.
- readPage/WritePage: sometimes the interrupted thread throws
the wrong exception: AsynchronousCloseException instead of
the more specialized ClosedByInterruptException.
[1] Note: DirRandomAccessFile4 also contain use of NIO, I'll address
that in a later patch.
I will also be adding more tests. A problem for making tests for
interrupts is to get coverage without making tests unstable, so I'll
wait until I have more holes plugged.
Regressions worked earlier tonight in a slightly different version, rerunning now.!!!
Thanks, Lily, for looking at the latest patch. I agree the code is a bit tricky, so there could be bugs. Feel free to ask detailed questions, I'll try to answer.
I did not see any issue with testPartialRowRTStats when I ran the regressions, nor would I expect this patch for increase perm gen space since it doesn't add new classes. But we have seen that perm gen space can be an issue when running regressions. I think I recently upped my pergen space setting for suitesAll to 192m. I have also seen failures in the replication tests, there are some instabilities left, but I don't think they are due to this patch.
You are right that the current test, InterruptResilienceTest, is pretty thin right now, but it does exercise the RAF recovery machinery with two concurrent threads (user thread and the raw store daemon).
I intend to make more tests; the trick is to make sure the tests actually exercise the code paths we want: just shooting interrupts at threads can land anywhere during execution, and Derby doesn't stand up to it in all places yet. I plan to use the SanityManager + a debug flag to simulate interrupt at selected places in the code. If you have suggestions for good tests, please let's have them
For testing idea, SanityManager + a debug flag sound good. I am trying to picture how it can cover all the code we try to hit. I am assuming we want to hit code like RAFContainer4.readpage. The simple insert case to Blob and Clob data type can be hitting it like the InterruptResilienceTest does. Will BlobSetMethodTest or LobStreamTest do the trick? A far stretch will be utilizing CorruptRandomAccessFile. I am thinking out loud here.
I had a look at the b-01-nio patch, and it looked correct to me. The
stealth mode part wasn't entirely obvious, but the comments were
helpful and the code appears to be doing the right thing.?
Some minor issues found in the patch:
1) Thread.holdsLock() is a static method, but all calls to it are done
on Thread.currentThread().
2) I think the checks for SQLState.INTERRUPT_DETECTED should use
getMessageId() instead of getSQLState(), since the SQLState interface,
despite its name, contains message ids and not SQLStates (although the
message id and the SQLState happen to be the same for this error).
And since INTERRUPT_DETECTED is only intended to be used internally,
would it make sense, instead of giving INTERRUPT_DETECTED a proper
SQLState and also an entry in messages.xml (which will be picked up
and translated unnecessarily later), to create a subclass of
StandardException for this error? Something like what's done with
NoSpaceOnPage, I mean. That could also make the catch blocks used to
handle this condition a little bit tidier.
3) Javadoc for RAFContainer4.readPage() should explain how the offset
parameter is supposed to be used (-1 for normal reads, actual offset
for embryonic pages)
4) The variable "whence" in awaitRestoreChannel() does not seem to be
used. Nor is its "pageNumber" parameter, I think.
And a note to others who consider reviewing the patch: I found that it was easier to see exactly what was being changed by running svn diff with the extra option "--extensions=-bw" to disregard whitespace changes in the parts of the code where an extra level of nesting was added.
Thanks for the review, Knut. Uploading a new version of the patch,
derby-4741-b-02-nio, details below, rerunning regressions.
- In RAFContainer4, folded the cases for pageNumber == -1 (call from
getEmbryonicPage) with the case Thread.holdsLock(this). This allows
awaitRestoreChannel to throw the retry exception for all cases. I
did both static and dynamic analysis to establish invariant, and
added a sane check for it.
>?
Yes, I believe we could do that, since it should do no harm to attempt
the IO even when recovery is in progress, because all calls to
getChannel are synchronized on "this" already, so either the thread
sees the old channel (closed), or the new reopened channel. I didn't
make this change yet, though, since the monitor hold should
short-lived (one boolean check and an integer increment) compared to
the IO.
- Thread.holdsLock(): done
- Created a new subclass of StandardException:
InterruptDetectedException, good suggestion, indeed cleaner!
- Javadoc for RAFContainer4.readPage: done
- The variable "whence": removed
- Removed some commented out debugging cruft
- Tuned the number of iterations in InterruptDetectedException to make
sure we see a a concurrent thread (RawStoreDaemon) having to wait
for cleanup before proceeding, at least on my box. Cf. the debug
trace for derby.debug.true=RAF4Recovery, which I also added.
Found that Derby uses interrupt to stop threads at shutdown[1]..
[1] BaseMonitor#shutdown
> notifyAllActiveThreads and in DatabaseContextImpl#cleanupOnError>notifyAllActiveThreads
This might sound wired. I am so happy you got this. I woke up to a hanging test for Suites.All and now I know why. Thank you so much for posting this and looking into this.
Add the following code in ClosedChannelException block in RAFContainer4.java->readPage and did not see any hang for Suites.All in Windows 7 enviornment:
if (pageNumber != -1L) gives up and throws FILE_IO_INTERRUPTED. The waiting threads will next see giveUpIO == true, and give up as well.
This should make sure that threads not doing the recovery, will detect that recovery will not happen, and throw as well. SuitesAll finished successfully. 7?
I have now run regressions with patch b-03 on Windows Vista SP2 without errors. Since the 10.7 branch has been cut, I intend to commit this patch soon, and move on the the next piece of the puzzle.
For reviewers of b-03, it may be interesting note that running InterruptResilienceTest with the flag -Dderby.debug.true=RAF4Recovery
will likely give one or more instances of this trace in derby.log:
DEBUG RAF4Recovery OUTPUT: derby.rawStoreDaemon thread needs to wait for container recovery: 0
showing that this part of the multi threading synchronization is being exercised: The user that was interrupted is doing recovery on the channel so the
thread printing this (i.e. RawStoreDaemon) has to wait for recovery to complete to be able to move on.
Hi Dag:
Thank you so much for all the detail message. The code looks good to me. I don't see potential issue. When I run insane build, I got 5.8 second for MicroAPITest and 51.x second for sane build vs 5.07s(insane) and 47.xs(sane) build on clean trunk. It could be just Windows platform issue.
+1 to check in to trunk.
HI Lily! Thanks! I'll commit it soon after I have verified a debug trace for observing the effects of the giveUpIO logic.
Uploading b-04, which cleans up and adds some more debug tracing to RAFContainer4.
Committed b-04 as svn 1038440. Note: I changed the debug trace flag to "RAF4" to accommodate an exisiting trace not related to recovery.
This patch (derby-4741-c-01-nio) closes two corner cases I have
observed when stress testing the RAFContainer4 recovery mechanism. It
does some other small cleanups. Regressions ran OK.
RAFContainer:
If we receive an interrupt when the container is first being opened
(i.e. during RAFContainer.run (OPEN_CONTAINER_ACTION) ->
getEmbryonicPage), recovery will fail because currentIdentity needed
in RAFContainer4#recoverContainerAfterInterrupt hasn't yet been
set.
RAFContainer4:
If a stealthMode read is interrupted and is recovering the container,
it erroneously increments threadsInPageIO just before exiting to retry
IO. This leads to a break in the invariant that threadsInPageIO be 0
when all threads are done, causing issue (hang) down the line.
If, when we are reopening the container, the read being done during
that operation (getEmbryonicPage), that stealth mode read will also
lead to a (recursive) recovery. We have to catch this case by adding a
"catch (InterruptDetectedException e)" just after the call to
openContainer, not by testing the interrupt flag as presently done,
since the recovery inside the recursive call to
getEmbryonicPage/readPage will already have cleared the flag and done
recovery.
When giving up reopening the container for some reason, we also forgot
to decrement threadsInPageIO.
To guard against other hangs, I will make the while-true loops max out
in all cases. But before I commit that change, it would be nice to see
if this patch has any impact on
DERBY-4920 (I suspect not). The reason
I'd like to hold off with that is that since
DERBY-4920 occurs during
shutdown, that may mask the fact that recovery failed, cf. my comment
So, I'd rather wait with that till I get
DERBY-4920 out of the way.
Committed derby-4741-c-01-nio as svn 1040086. Please let me know if you still see the hang of
DERBY-4920 and, if possible, during execution which test it happens.
Happened to look at parts of the new code, and have a few questions/comments on code in RAF4Container:
o in writeFull the variables beforeOpen and beforeInterrupt are unused. Can they be removed?
o the same issue in readFull.
o would it make sense to make the monitor object channelCleanupMonitor final?
o redundant call to Thread.currentThread when invoking holdsLock.
o missing JavaDoc for recoverContainerAfterInterrupt
A more theoretical question at the end.
Is there a reason to explicitly define instance variables with the default value for the data type?
I.e., int i = 0, boolean b = false.
Just asking, as I find it annoying to step through these in the debugger
Thanks for looking at the new code, Kristian, I'll make a new patch to cater for your comments.
> o in writeFull the variables beforeOpen and beforeInterrupt are unused. Can they be removed?
> o the same issue in readFull.
Absolutely, debugging cruft. Thanks for spotting those.
> o would it make sense to make the monitor object channelCleanupMonitor final?
Absolutely.
> o redundant call to Thread.currentThread when invoking holdsLock.
Thanks, thought I had cleaned out those, but there were two left!
> o missing JavaDoc for recoverContainerAfterInterrupt
Added Javadoc for recoverContainerAfterInterrupt and awaitRestoreChannel.
> A more theoretical question at the end. Is there a reason to
> explicitly define instance variables with the default value for the
> data type? I.e., int i = 0, boolean b = false.
No. I tend to often use explicit initialization due to my paranoid
streak I guess. I see the data flow analysis barks if you use a local
variable uninitialized, although not for a class member, not clear to
me why Java differentiates here.
public class Foo {
public boolean bb;
public static void main(String[] args) {
boolean b;
if (args.length > 0 && args[0].equals("foo")){ b = true; }
if (b){ // compiler barks System.err.println("b is true"); }
Foo f = new Foo();
if (f.bb)
}
}
I guess I have tended to treat them the same. I'll try to improve
Uploading derby-4741-kristians-01, running regressions..
While I am looking for the Heisenbug in
DERBY-4920, I am considering the next increment of this patch from the
prototype patch regarding the issues seen when interrupt hits the logging machinery (mostly not NIO, except for the case of DirRandomAccessFile#sync).
Now, it turns out that the vulnerability here only applies for Solaris. Other platforms' "non-NIO" IO is not interruptible, so for those other platforms there is no need to do anything special. For Solaris, the behavior can be tweaked to be impervious to interrupts as well using the special switch: -XX:-UseVMInterruptibleIO on JVMs >= 1.5.0_12. This behavior will be default in 1.7 also on Solaris[1].
So the question becomes, would it be sufficient to advise users to run with this switch set, or should we make Derby tolerate
the interrupts on Solaris here also?
I do think we should be able to run correctly with the default settings on all relevant platforms, but I would appricate your opinions.
[1]
Committed derby-4741-kristians-01 as svn 1043802 (suitesAll ran ok).
> So the question becomes, would it be sufficient to advise users to run with this switch set, or should we make Derby tolerate
> the interrupts on Solaris here also?
How much code do you think will be needed to handle that case? Handling interrupts sent to the engine is somewhat of an edge case in itself. Since this particular problem only affects one platform, and that platform will start behaving the same way as the other platforms in the not so distant future, it sounds acceptable to just advise those who come across the problem to set the flag. Of course it would be nice if Derby was well-behaved by default on all platforms, but given the easy workaround and the expectation that the problem will soon go away by itself, I'd say that it's probably not worth putting a lot of work into and/or adding more complexity to already complex code.
Thanks for your thoughts on this, Knut.
Here is another issue: The NIO Channel#force call is used to implement sync when we flush the Derby log, cf. this call:
LogToFile#flush -> LogAccessFile#syncLogAccessFile -> StorageRandomAccessFile#sync -> getChannel().force(false)
The "false" here allows the skipping of flushing metadata, which makes this faster (at least on Solaris) than the non-NIO
implementation of StorageRandomAccessFile#sync, which uses getFD().sync().
Unfortunately, an interrupt will make the getChannel().force call throw ClosedChannelException, and I can't see an easy way
to recover from this, except assuming the log is corrupt and shutting down the database instance, so we can recover on reboot.
If we switch back to using "getFD().sync()", we would lose the performance optimization, but be resilient to interrupts.
So, unless somebody can see a way to finesse this problem, should be offer a knob to allow a user to trade this performance optimization for interrupt resilience?
Aside: we also use StorageRandomAccessFile#sync in many other places, but in those situations I find I am able to recover by closing the RAF, reopening and writing over again, since the data to be written is known, e.g. in LogToFile#initLogFile.
I find that explicit file sync (i.e. not "write sync") is only used if:
a) NIO is not supported (cf. WritableStorageFactory#supportsWriteSync), in which case we never use FileChannel#force
b) derby.storage.fileSyncTransactionLog is set to true
c) we are running on platforms/VMs that don't support opening a file with mask "rws" (write sync with metadata) and "rwd" (write sync without metadata), cf. check in LogToFile#openLogFileInWriteMode which calls checkJvmSyncError to determine this. The platforms mentioned are (e.g. early versions of 1.4.2 and 1.5 on Mac OS and FreeBSD).
If this holds, it seems to be we can just skip using the NIO version of RAF#sync for those platforms. Other platforms do not use the explicit file sync for the log, cf. the test in LogToFile#flush (snip):
if (isWriteSynced){ //LogAccessFile.flushDirtyBuffers() will allow only one write //sync at a time, flush requests will get queued logOut.flushDirtyBuffers(); }
else{ if (!logNotSynced) logOut.syncLogAccessFile(); }
On most platforms, isWriteSynced is true (cf above), meaning syncLogAccessFile is not used, so reverting to a interrupt safe, less performant non-NIO sync in syncLogAccessFile seems acceptable to me. Opinions?
I agree with the tradeoff you suggest concerning syncing the log file. It seems to make the code easier and will not really affect most users running on modern platforms while still allowing those few to still work correctly on back releases. This especially seems to make sense as I don't see us backporting this change so should only affect 10.8.
Thanks, Mike. Logged and fixed
DERBY-4963 to revert NIO version of RAF#sync.
Committed a followup patch as svn 1057733. Quoting the commit entry:
> Followup to patch derby-4741-b-04-nio committed as svn 1038440:
> changed the string internal exception string "nospc.U" to "intrp.U".
Uploading a patch derby-4741-sleeps-waits-1 which adds handling of some cases of interrupted monitor wait calls and Thread.sleep calls which I found needed changes to make my preliminary tests work. Running regressions.
There are remaining places (i.e. usages for wait & sleep) in the code base which need to be inspected for modification. I will be making one or more follow-up patches to handle those. With the current patch
this work is approaching a state where Derby embedded(**) is sufficiently robust against interrupts that I will move to buillding systematic as well as randomized tests, and plug remaining holes as we find them.
After commits of
DERBY-4967 and DERBY-4968
(**) the server code needs consideration too, as well as the client code and replication.
suites.All passed.
Some details on where patch derby-4741-sleeps-waits-1 changes things.
The following locations where we earlier threw 08000 (CONN_INTERRUPT),
we now just note that an interrupt occurred:
- GenericStatement#prepare:
- while waiting for another thread to complete the compilation of
the statement
- LogToFile
#checkpointWithTran:
- while waiting for another thread to complete a checkpoint
#switchLogFile:
- while waiting for a semaphore needed to make sure the log switch
can complete "without having to give up the semaphore to a backup
or another flusher".
#flush:
- while waiting for the database to stop being frozen
- while waiting for another thread flushing
#syncFile
- while waiting a bit before retrying a failed sync call
#startLogBackup
- while waiting for a thread doing checkpointing before we start
backup of log as part of online-backup
The following locations previously silently swallowed the interrupt, we
now (also) note that an interrupt occurred:
- LogToFile
#recover:
- in slave replication mode, while waiting for fail-over. This code
swallowed the interrupt
#getLogFileAtBeginning:
- in slave replication mode, while waiting for SlaveFactory to tell
the thread to do recovery. This code swallowed the interrupt
- BasePage:
#setExclusive:
- while waiting for an exclusive latch
- while waiting for cleaner to finish
#setExclusiveNoWait
- while waiting for cleaner to finish
#syncFile
- while waiting a bit before retrying a failed sync call
Should the comment change a little in turn of the "does not matter..."?
I run suites.all against ibm 1.6 jvm along with the LockInterruptTest.java (derby-4967-locking-2.diff) change, test run clean.
Thanks for test running the two patches, Lily. Good to know these run on the IBM VM as well!
As for the comment, agreed. I have removed it in my next version of this patch, because it long longer seems to carry important information: earlier practice was to always throw, so then the comment highlighted "unusual" treatment. Now we mostly do not throw, just make a note, so this is code is no longer unusual as I see it.
Uploading a second version of derby-4741-sleeps-waits, rerunning regressions.
Details on where patch derby-4741-sleeps-waits-2 adds things relative to version 1:
The following locations previously silently swallowed the interrupt, we now (also) note that an interrupt occurred:
- LogAccessFile:
#flushDirtyBuffers:
- While waiting for another thread flushing
#syncLogAccessFile:
- While sleeping a bit before retrying after a failed sync
With the above, all the waits and sleeps in the package
org.apache.derby.impl.store.raw.log have been made safe.
The following locations where we earlier threw 08000 (CONN_INTERRUPT), we now just note that an interrupt occurred:
- XactFactory:
#blockBackup:
- While doing backup blocking operations, we wait for backup to
finish.
#blockBackupBlockingOperations:
- While waiting for all backup blocking operations to complete
- BaseDataFileFactory:
#freezePersistentStore:
- While waiting for writes in progress to finishing before freezing.
#writeInProgress:
- While waiting for db thaw before we can start writing
- CachedPage:
#clean:
- Waiting for another thread cleaning it
- Waiting for state to become unlatched attempting to clean it
- AsynchronousLogShipper:
#run:
- If interrupted during the shipping interval wait, shipping sooner doesn't hurt
#forceFlush:
- While waiting a bit after having flushed the master to ship log records to slave to free up buffer space
- ReplicationMessageReceive:
#isConnectedToMaster:
- While waiting for result from the ping thread (the "pong"). Since we may have been interrupted before the result is ready, we try again unless the connection is confirmed up.
#SlavePingThread#run:
- While waiting for wakeup to do a ping. I had to introduce an extra state variable here to decide whether after we receive an interrupt, a ping request has also been lodged.
Second revision of sleeps-waits looks good to me. A couple of questions:
XactFactory.blockBackupBlockingOperations(): Remove RuntimeException from throws clause? The explanation added to the javadoc is probably enough for documentation purposes.
RAFContainer4.java:
- Why the change from noteAndClearInterrupt() to setInterrupted()?
- Whitespace diff @@ -825,7 +819,7 @@ looks unintended.)
> XactFactory.blockBackupBlockingOperations(): Remove RuntimeException from throws clause? The explanation added to the javadoc is probably enough for documentation purposes.
I'm ok with that, I was torn on this.
> RAFContainer4.java: Why the change from noteAndClearInterrupt() to setInterrupted()?
Just simplification, since in these two locations we know that an interrupt actually did happen, there is no need to test for the flag as noteAndClearInterrupt does.
> - Whitespace diff @@ -825,7 +819,7 @@ looks unintended
Indeed, thanks.
>
>.)
Yes, I agree the original code is deficient in this repect, I have the code changed to handle this as well.
Uploading rev #3 of sleeps-waits, rerunning regressions.
Committed rev #3 as svn 1061516. This completes the cleanup of interrupt handling in Object#wait and Thread.sleep inside store.).
Do we need a separate jira?
Uploading *-raf-stresstest-1, which adds a multi-threaded read/write test under an interrupt shower.
This exercises primarily the random access file recovery (RAFContainer4#recoverContainerAfterInterrupt), but since the interrupt can arrive at any time during query execution, other parts of the code are also exposed.
The new test case is InterruptResilienceTest#testRAFReadWriteMultipleThreads.
Running regressions.
The patch is not for commit yet, since I worry that the test takes too long to be included in the regression suite. During development I had to let it run this long to expose all the corner cases I have seen, but adding 250 seconds may be too much. I could comment out the client/server suite, since it doesn't add much value: the interrupt all happen on the server side. That would cut the time down to ca half. Also, the test may not be entirely reliable yet, since there are remaining parts of the code yet to vetted wrt interrupt handling, but it runs reliably in my environment. I will at least run it on some more platforms before I suggest any commit.
Please note that due to DERBY-4431, the IBM VMs will not yet be covered by these additional tests.
Myrna, I will look into it. Filed
DERBY-4982 for this.
Regrressions for *-raf-stresstest-1, and I verified that the modified InterruptResilienceTest works on Windows as well. For some reason it executed much more quickly under Windows, ca 50s (the reported 250 above was on Solaris). I'll see I can figure out why.
Perhaps the difference is whether or not the OS will force changes to disk when doing synchronous writes?
The use of the static field thisTest may have some consequences that are not entirely obvious:
The field is set when the test suite is created, so when the tests start running it will always point to the last test case that was created, not necessarily to the running test case. That is, it will always point to a client test case. Because of this, one may be led to believe that the test that calls thisTest.openDefaultConnection() always uses client connections. However, BaseJDBCTestCase.openDefaultConnection() calls TestConfiguration.getCurrent() to get the current test configuration, so the connection type should be chosen dynamically based on the active decorators. But this assumption is also not quite true. The decorators only affect the TestConfiguration for the main thread, so when running inside a stored procedure in a server thread, the decorators will have no effect, and an embedded connection will be opened even if the test case is actually running within a client/server decorator.
I think the intention is to always use embedded connections inside the stored procedure, and that's also what the code does (so, as mentioned in an earlier comment, there's probably not much point in running this test in client/server mode?). But it takes some effort to convince oneself that that's what it actually does. Do you think it's possible to make it more explicit that the worker threads always use embedded connections?
And some little nits:
+ if (w.e != null){ + fail("WorkerThread " + i + " saw exception " + w.e); + }
Use the fail() method that takes an exception to preserve the stack trace?
+ ResultSet rs = s.executeQuery("select count
from mtTab");
+ rs.next();
+ assertEquals("too few rows inserted",
+ rs.getLong(1), NO_OF_THREADS * NO_OF_MT_OPS);
+ rs.close();
How do you know it must be too few and not too many?
JDBC.assertSingleValueResultSet() could simplify this code.
Thanks for looking at this, Knut!
You are right, it got a bit convoluted. The intention is, as you suggest, to always embedded connections inside the stored procedure.
I'll see if I can simplify this a bit! I
always agonize about whether to include c/s tests or not when the changes are seemingly embedded/server-side only, maybe we should try to establish some criteria to help us decide when to, and when not to do that.
Thanks also for spotting the nits, I converted this from a stand-alone test outside JUnit, so it can be further simplied as you suggest.
Uploaded *raf_stresstest-2 which supersedes #1. In addition to fixing Knut's nits,
the server side code now uses a thread's default test configuration directly, and I also added a comment explaining this. I think I will commit the patch with the long running time for now. I'd rather flush out any bugs here sooner rather than later.
> I think I will commit the patch with the long running time for now. I'd rather flush out any bugs here sooner rather than later.
Sounds good. +1
> I always agonize about whether to include c/s tests or not when the changes are seemingly embedded/server-side only
I don't have a general rule, but in this particular case it looks like we run the entire test inside a stored procedure in order to make sure that only embedded is tested. Sounds like a good indication that embedded only would suffice...
We could probably simplify the test somewhat and remove the stored procedure indirection too if we made it embedded only.
Uploading a revised version #3 which makes use of derby.system.durability=testing to cut down on the
running time on Solaris, I found it will still get to the corner cases.
Uploading version #4 (derby-4741-raf-stresstest-4). This lets the test run with its own database since we use durability=test: just to be on the safe side, so other tests don't get impacted by the fact that the database is thus marked, cf. message in derby.log:
"WARNING: The database is booted with derby.system.durability=test. In this mode, it is possible that database may not be able to recover, committed transactions may be lost, database may be in an inconsistent state. Please use this mode only when these consequences are acceptable" (sic: no final period)
I has to add a class.forName to DriverManagerConnector#getConnectionByAttributes and a new public method BasicJDBCTestCase#openDefaultConnection(TestConfiguration). The latter makes it possible use the main thread's test configuration in the server threads, cf. "thisConfig" member in InterruptResilienceTest.
I also added derby.infolog.append=true to SystemPropertyTestSetup, so the c/s run doesn't clobber the embedded run's derby.log.
Rerunning regressions.
Regressions ran ok, committed derby-4741-raf-stresstest-4 as svn 1064174.
Uploading a functional specification for this work to summarize what we have so far: "interrupts-fs.html"
Uploading a patch, *-testQueryInterrupt, which:
- adds a new test case: InterruptResilienceTest#testLongQueryInterrupt
which tests that a query will check for the interrupt flag and throw 08000 (CONN_INTERRUPT) at the same time is checks for query time-out.
- adds a missing test in InterruptStatus#throwIf
I also adjusted an existing test (for RAF recovery) to handle the case that we could see 08000 (CONN_INTERRUPT) when performing a query as part of that test, depending on when the interrupt happens.
Regressions passed.
Uploading a new version of the draft functional specification, version 0.2. Please have a look!
Uploading another patch *-testBatchInterrupt, which adds another fixture to InterruptResilienceTest: #testInterruptBatch, rerunning regressions.
It tests that an interrupt will stop a batch of statements by throwing just before we execute the next statement in the batch.
Note that this patch includes all of *.testQueryInterrupt also for logistics reason (that patch is not yet committed), but I will post a slimmed down version of this as soon as that one is in.
Committed patch derby-4741-testQueryInterrupt as svn 1066701.
Uploading version a slimmed-down version of *-testBatchInterrupt: derby-4741-testBatchInterrupt-b.
Committed derby-4741-testBatchInterrupt-b as svn 1066707.
Thanks for writing up the functional spec, Dag. I found that it clearly explained the behaviour, and as far as I could see it matched what was actually implemented. It doesn't mention anything about how to handle the Solaris interruptible I/O issue on JVMs later than 1.6 (in which case there won't be an issue, right?), but that's probably intentional since 1.7 is still only available as early access?
Yes, you are right, Knut. I did omit reference to the 1.7 behavior on Solaris, but it might be good to include it in any case for completeness. After all Java 1.7 should be available before too long
Thanks for reviewing the specification.
Hi Dag,
Thanks for the functional spec. I am trying to wrap my mind around what application writers can expect. Is the following a fair summary?
1) If the Thread is interrupted while running outside Derby (that is, not inside a JDBC call), then Derby does not field the interrupt. The Connection remains alive and Thread.isInterrupted() will not be touched by Derby.
2) On the other hand, if the Thread is interrupted while running inside a Derby JDBC call...
a) The Connection may be killed and have to be restarted. If the Connection is killed, then Thread.isInterrupted() will be true.
b) Alternatively, it is also possible that the interrupt will not kill the Connection. In this case, the state of Thread.isInterrupted() is unclear to me. I am having a hard time reconciling "will be still be set...when exiting from the Derby API method" with "it is not deterministic whether the flag will remain set or be cleared on return".
Thanks!
Thanks for reading the spec, Rick.
1) Not true. If the flag is set at the time the Derby API call, Derby may throw. Derby can't know exactly when the thread was interrupted, it can only notice it by either a) seeing Java API methods return exceptions, or b) testing the flag explicitly. We do not test the flag on Derby API method entry. We heed (i.e. throw) interrupts in the specified situations enumerated in the spec.
2b) The flag will remain set when exitting from in all cases. The note about deterministic only applies if the flag is attemped cleared by another thread while the Derby API call is still executing. If we ever saw an interrupt and had to clear it to make execution continue, e.g. for NIO, we set it again at Derby API method exit, whether we throw or not. This means that any attempt to clear it while Derby is executing could be lost, depending on exactly when the clearing attempt was made, hence "non-deterministic".
Thanks, Dag. Some follow-on questions:
1) Suppose my application has two threads T1 and T2, each with its own Connection. T1 is busy interacting with the user and is NOT stalled inside a JDBC call. T2 is running inside a JDBC call. Now T2 is interrupted. Can this kill T1's Connection?
2) Does this give rise to any advice for application writers?
Thanks,
-Rick
Hi Rick,
1) The answer is no. Only T2 risk seeing 08000. Nor would T1 risk it if it were inside a JDBC call, since this thread is not being interrupted.
2) Applications that expect to interrupt threads while they are executing JDBC calls should be prepared to receive a session level error with SQLState 08000, and so would need to reconnect in order to get more work done.
Thanks, Dag. Here is another attempt to summarize the user-visible behavior after these improvements.
If an application experiences Thread interrupts, its designer should plan for the following behavior:
1) If a Thread is interrupted inside a Derby JDBC call, then the Connection experiencing the interrupt MAY be terminated. If the Connection is terminated, the application will experience the following consequences:
a) The JDBC call will raise a 08000 (CONN_INTERRUPT) exception.
b) Outstanding transactional work on that Connection will be rolled back and all of its locks will be released.
c) The Connection will not execute any further JDBC calls.
d) On return from the interrupted JDBC call, the Thread's isInterrupted() method will report "true".
2) All other Connections will remain active. This includes other Connections which the interrupted Thread may be using.
3) Application designers are advised to catch these 08000 exceptions, discard the dead Connection, and restart their transaction in a new Connection.
>.
Uploading a new version of the func spec.
Thanks for the extra clarification, Dag. That will be useful for programmers who want to understand the code. I think we have a clear enough picture of the user experience that we can document this feature now. Thanks.
triaged for 10.8.
A lot of progress has been made on this issue, and it looks ready for 10.8. Work is being done incrementally, probably soon should close this one based on checked in work, and log a new one to track possible work post 10.
Uploading version 0.4 of the functional specification. Adds items to the list of unmodified behavior.
Dev guide:
> Do not use interrupt calls to notify threads that are accessing a
> database, because Derby will catch the interrupt call and close the
> connection to the database. Use wait and notify calls instead.
This advice stands still, I think. The modal verb "will" is slightly
inaccurate here, it would be more correct to use "could" or
"might". The functional specification spells this out in detail when
this can happen.
Interrupts can now be used to stop long-running queries, batches and
statements that wait for database locks. In all cases, the connection
will be closed along with the exception seen (state 08000), cf the specification.
Thanks! Does "long-running" apply to all three nouns ("queries, batches and statements that...") or just the first?
Committed derby-4741-sleeps-waits-more as svn 1073595:
Commit message:
Patch derby-4741-sleeps-waits-more, which "regularizes" a few more
instances of interrrupt handling to follow the idiom established in
this issue's patches.
This leaves a few instances in BasicDaemon.java (as far as embedded
code is concerned), which will need more consideration. In any case,
interrupting the demon threads is less of a valid use case I believe,
i.e. Derby's ability to tolerate that is less crucial that tolerating
interrupts to the user's connection threads.
(reposting my answer from email here, since it didnt seem to make it to the JIRA issue)
Kim> Does "long-running" apply to all three nouns ("queries, batches and statements that...") or just the first?
Good question. All: I guess the definition of "long" here is relative to
the applications expectations. The third one (locks) is limited upward
to the lock timeout for a single lock grab, but that may not be the
whole story since the statement may need further locks to complete. So
"longer than expected" is perhaps more to the point..
The last commit (#1073595) seems to have introduced some dependency that breaks the build in the Tinderbox:
I am able to reproduce it if I explicitly point the jsr169compile.classpath property to Foundation + JSR-169 jars. I'm not sure exactly what's causing it, but it looks like the iapi.types package now is compiled via the compile_mbeans target. That target uses compile.classpath, which is set to jsr169compile.classpath in build.xml, whereas the target that normally compiles SqlXmlUtil requires some extra XML libraries on the compile classpath.
I backed out a change to TopService.java until we understand how to make it build correctly in those circumstances.
svn 1073846.
Uploading a patch which reintroduces the fix that was backed out with changes to the build. Essentially it moves the compilation of MBeans out till after the iapis have been built. Thanks to Knut for pinpointing the feact that compilation of MBeans depends on Monitor, but is in fact compiled before the iapi currently. Setting the sourcepath for javac to "" for mbeans-compile highlighted the issue, cf this comment:
Still,exactly why this makes it compile with explicit setting of jsr169compile.classpath now, whereas it did not before, is still a bit unclear to me. It seems to work now, though. Running regressions.
It is not totally clear to me why setting for the sourcepath and jsr169compile.classpath make the build work on all the platforms. More explanation will help people like me. :-
Suites.all and derbyall run clean with derby-4741-fix-compilation.diff patch on my Windows 7. +1 for me to commit. Cheers and Thanks!
Hi Lily, it is not clear to me either
The dependencies in our
present compile is partly hard coded in the build.xml files, but that
is not the whole story. It seems that if the compiler notices it lacks
a class, it can check for it in the source path and compile it outside
the normal order to fulfill the dependency. Setting the classpath to
"" denies the compiler task this ability, forcing the hard coded
dependencies to be the unique determinants of compilation order. Knut
did an experiment to do that for most compiles, but it quickly turned
messy as far as I understood.
Cf this quote from the javac task doc ():
. "
So far so good. I can't explain why setting jsr169compile.classpath
explicitly made things break though. I just fiddled with the placement
of the compilation of mbeans till it worked...
But in general, it
matters under which javac tash a class is compiled in Derby, since we
use so many tweaks for classpath handling to enable seperate Java
versions, jsr169, JDBC3, 4... I think it woul dbe good if we could
move to having the dependencies better understood and encoded in the
build files, cf. Knut's experiment, so we can untangle all these
intricate dependencies, and suffer less every time anything changes..
Committed 1074789 (derby-4741-fix-compilation). I don't plan more work on this feature now, resolving.
Thank you so much, Dag. I couldn’t agree more. We should define the dependencies better and move toward to more fine rule in the build files and have easier life every time we need to change thing to make Derby better. A lot of things appear to be easy but take a lot of time to do once you get all the details. :- The devil is always in the detail.
[bulk update] Close all resolved issues that haven't been updated for more than one year.
Since Derby used to handle interrupts in a better way before we switched to NIO, would it make sense to change the issue type to bug and flag it as a regression?
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A tiny post for something I’ve just worked out. If you’re using Oxide, the Ubuntu web rendering engine (based on Chrome’s Blink) in an Ubuntu SDK QML app, it’d be useful to have access to the devtools inspector so you can debug it. Well, you can, although this doesn’t seem to be documented anywhere. Adnane “daker” Belmadiaf wrote a useful post describing how to use Oxide in your Ubuntu QML application but unaccountably didn’t explain how to turn on the dev tools1 so this is how to do it.
Give your
WebView a
WebContext and set its
devtoolsEnabled and
devtoolsPort properties. That’s it.
import com.canonical.Oxide 1.0 WebView { ... context: WebContext { devtoolsEnabled: true devtoolsPort: 9232 } }
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We!
Thank You this team.
Thank You Team, Please make Exchange Server Role Requirement Calculator similar to Lync Planning tool.. which is a good GUI tool.
Thanks, Great for Exchange On-Premises Customers moving to Exchange Server 2013 SP1.
New updates are always appreciated – please consider updating the Hybrid deployment scenario for a 2007 on-prem with 2013-based hybrid scenario, as it recently bit us with a customer during the portion where we re-pointed client access from 2007 to 2013.
If you begin the deployment the assistant with the intent to build an on-prem 2007/2013 coexistence scenario, all the proper guidance is given, including the creation of a Legacy namespace for 2007 OWA, along with updates to the internal and external URL attributes of some of the 2007 virtual directories. Under the 2007/2013 hybrid scenario, however, the assistant provides no guidance as to the configuration required on 2007 – it strictly works through the DNS and virtual directory modifications for 2013 and ignores 2007.
@Varol – thanks for your feedback, I’ll double-check to make sure there aren’t gaps between the 2013/2007 hybrid and coexistence scenario guidance. Could you also post your question to edafdbk@microsoft.com so I can follow up directly with you about any specific follow-up questions if needed? Thanks!
@Martijn – You can either print or save the entire checklist after you’ve selected a specific scenario track (On-premises, Hybrid or Cloud Only) and have answered the associated qualifying questions for that scenario. Click the Print Checklist icon at the top of any page to print the entire deployment checklist (or you can also use Print This Page icon at the bottom of each page to print just a single checklist step).
Please provide option to download checklist
Thank You this team.
Very interest article.
THANKS
Please provide an option to download the checklist.
Martijn
Hi, just wondering if the pre-reqs have changed or its a typo, you mention the following sentence in the deployment assistant, but I thought only RU10 for E2K7 SP3 was needed.
You need to install Update Rollup 13 for Exchange 2007 Service Pack 3 (SP3) on all the Exchange 2007 servers in your organization before you can install Exchange 2013. Download from Exchange Server 2007 Service Pack 3 and Update Rollup 13 for Exchange Server 2007 Service Pack 3 (KB2917522).
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Steve Zilles (Independent): To
repeat my challenge, can we find the key 5-7 things to focus on
and not try to solve all the world's problems?
TV Raman (IBM): And how do you measure success?
Unidentified Speaker: I think
success is when we have the same people who authored HTML in the
1990's do web apps.
Patrick Schmitz (Nirvana): I disagree -- there aren't as many people who need to expose functionality as those who just have something to say. I think that compound documents leverage the same framework as web apps, but they are different things. There are many, many more people who just want to say something.
Chris Lilley: Those people do use software, for showing their family photos or talking to strangers for 10 minutes. A criterion for success would be buying inexpensive shrink-wrapped software that lets you author that. If you want something more complex, you have to be a programmer anyway. Some things are more than interactive documents and are in some sense applications.
Doug Schepers (Independent): Small applications can be aggregated into larger ones, a color picker and a graphics app for example, making a compound aggregate web app by people who aren't programmers.
Patrick Schmitz (Nirvana): Then it's constrained to people who have done CGI and PHP.
Glen Gerston (Ideaburst): The web has lots of copied-and-pasted code. We could develop tools that allow people to generate that type of code, or have the runtime environment have standardized widgets with drag and drop and an app. We set out to make a facilities management app. It took about two months and we made it more extensible, easier to use, easier to maintain, and now it is two years. It's not easy to write interfaces from scratch. We need the tools to be able to deliver those types of applications in a short timeframe. We spent most of that time on our interface widgets. I'm sure the Laszlo people could tell you how long it took them to develop widgets in Flash. When the tools are there, people will start developing things.
Doug Schepers (Independent): That's the real revolution -- when people start using it.
John Boyer (PureEdge Solutions):
I am not sure about
Chris Lilley's point. Spreadsheet users are not programmers but they can leverage the power of a computation system to get their work done. One of our enterprise customers is converting 10,000's of forms over to this technology and the people who can use point-and-click are several pay grades below programmers.
Alex Hopmann (Microsoft): I am
hearing lots of good comments; people are hopeful that it's
possible to bring tools to people to let them do. That's nothing
to do with this workshop. If you want to help non-programmers
build things, like Lotus Notes or Apple Hypercards does, that's
not where design by committee can help.
Glen Gerston (Ideaburst): Everything is design by committee. We need file access, we need things that real applications have. There are security issues, but the problem can't be solved, or minimized. Having developed some SVG applications, it's not there for applications yet. We need more things to make it easier to do.
John Boyer (PureEdge Solutions): Alex's company and others produce spreadsheets; it gets this kind of stuff out to the masses. Standardizing business processes like this gives the underlying ability to create design tools to manage complexity.
Glen Gerston (Ideaburst): Yes, we could resell our widget set, but it's slow and inefficient compared to a runtime environment. It's applicable to standards organizations. Dynamic layout management is computationally intense. Doing it like HTML tables is more efficient than in the running code.
Dean Jackson (W3C): Alex can respond in the next break.
Jalava Teppo (Helsinki University of Technology): Styling is done with CSS, time ordering done with timesheet sequence. XForms used, and then the HTML.
Patrick Schmitz (Nirvana): Have
you thought about compound documents, not just
multi-namespace?
Jalava Teppo (Helsinki University of Technology): We have just started on this project and have not done that work yet.
Mark Birbeck (x-port.net): Is the only thing that changes visibility, or is the CSS connected to the timeline?
Jalava Teppo (Helsinki University of Technology): Yes, you can change the server class from the timesheet.
Mark Verstaen (Beatware): We are putting in the same sandbox for the desktop, Excel and xxx. This approach is good for in-depth developers. For generalizing the use of SMIL, we need to have tools for the normal users of SMIL, not programmers; we need tools.
Jalava Teppo (Helsinki University of
Technology): Yes, we use selectors.
Ian Hixson (Opera Software): You might want to look at the CSS WG presentation levels, which is not as powerful.
Erik Hennum: DITA is the Darwin Information Typing Architecture, an OASIS XML standard for human-readable topics (content objects). Evolving niches can be retired in favor of more general designs.
Patrick Schmitz (Nirvana): How
about styling, event flow, and timing across compound document
boundaries?
Erik Hennum: DITA takes a standard XML perspective of separating styling and presentation from content. It doesn't take a stand on timing.
Patrick Schmitz (Nirvana): In transclusion one author may prohibit change and the including author wish to control it. Similarly, interaction in sub documents vs. at the compound document level.
Erik Hennum: I don't think that DITA has addressed those issues, allowing application of the transcluded fragment to provide style or interaction hints to the transcluding document. It is an interesting question. I am glad you raised it.
Patrick Schmitz (Nirvana): How about fragment context when transcluding? XML fragment interchange...
Erik Hennum: Not addressed yet.
Michael : Device, Browser,
Pre-processor, Document
Michael : All processing steps for
Michael : A proposal
Cameron McCormack (Independent):
Do you use constraints for layout on different devices?
Michael Pediaditakis (University of Kent): We use selection constraints for templates for different devices. You choose the most appropriate one.
Mark Birbeck (x-port.net): I argued for a dynamic InfoSet in my paper; wiring in conditions and calculations and state automatically maintained. You want the same mechanism but different rules. I would argue for moving this into a module and do it without XML markup inline -- the rules up at a metalevel.
Paul Topping (Design Science): Screen readers can read the web page and query the MathPlayer supports accessibility and use its math-to-speech conversion. The screenreader has to reach through the HTML to do this. Search is similar. MathZoom magnifies equations.
Paul Topping (Design Science): The font has to be taken from the enclosing paragraph and there is interchange between the widget and the HTML layout engine, unlike in displaying images. CSS doesn't deal with expressions in the middle of a paragraph and a comma. The comma flops down to the next line when you shrink the window. There needs to be a richer model for nested content, with role indicated.
Paul Topping (Design Science): If an application needed to know that it could speak the math, or implement certain features, the server needs to know.
Doug Schepers (Independent): Have
you tried using SVG fonts, which don't need to be installed and
can be used as text.
Paul Topping (Design Science): SchemaSoft did a MathML to SVG conversion; it might have performance problems and accessibility.
Chris Lilley: To clarify, use SVG Fonts, not SVG. Use your own renderer, so it would help with baselines.
Paul Topping (Design Science): We have the OS access and an installer so it can install fonts. SVG would not solve our problems.
Mark Birbeck (x-port.net): We have XForms using MathML inside hints and select1 in FormsPlayer with your MathML player, with nested content as you describe.
Paul Topping (Design Science):
I'm not up on XForms, but would MathML be able to specify its
relationship with XForms if the label were an entire paragraph?
Or a MathML expression with hats? Would it do enough formatting
to know where the baseline is?
Mark Birbeck (x-port.net): I agree, you need the communication. The layout is done by MathML and we don't know what is happening. That is the same with the Adobe SVG player; it manages its space, but the space is controlled by the parent.
Dean Jackson (W3C): Let's pick this up again.
Paul Topping (Design Science): Internet Explorer has an interface where we can specify the baseline and I'd like that on all platforms.
Mark Birbeck (x-port.net): I agree.
Steven Pemberton (W3C/CWI): On day of release, more implementations than any other W3C specification on day of success. There are major implementations from IBM, Novell, Oracle, Sun, xport.net, .... And major users from US Navy, Bristol-Myers-Squibb, Frauenhofer, Daiwa, British Life Insurance Industry, and more...
Steven Pemberton (W3C/CWI): The central ideas of XForms are that:
model) from the markup for the controls to enter and change the data.
Steven Pemberton (W3C/CWI): -Memory -IO -Calculation -Presentation
Steven Pemberton (W3C/CWI): The data is one or more XML documents, internal or external. Input, output, data properties, calculations...
Steven Pemberton (W3C/CWI): Like spreadsheets, declarative. Uses XML Events. Usually don't need scripting, but still an option.
Steven Pemberton (W3C/CWI): In the 80's I build a completely declarative system. It ran on an Atari ST. I found a 1000 line analog clock code. Here is the declarative code for my clock (shows example about 20 lines).
Steven Pemberton (W3C/CWI): XForms can be hosted in different languages, use CSS for presentation, bind to SVG, etc. There are even model-only (no UI) implementations of XForms.
Paul Topping (Design Science): I
notice that the baseline of the text in the label doesn't match
the label.
Steven Pemberton (W3C/CWI): I am running this in IE and haven't done any CSS control.
Paul Topping (Design Science): Does XForms deal with it?
Steven Pemberton (W3C/CWI): We use CSS. CSS3 is adding properties to address the subparts of controls.
Cameron McCormack (Independent):
Can the model affect things other than the controls? Can it
affect CSS properties or positions?
Steven Pemberton (W3C/CWI): That's not the prime intention but you can see examples from Mark Birbeck.
John Boyer (PureEdge Solutions): Here is my form, it is a blackjack game.
John Boyer (PureEdge Solutions): Here is another one, a 15 puzzle. We have made all these fun things with the same feature set as forms, and we view them as Webapp-complete.
John Boyer (PureEdge Solutions): Here is a tax form example. There might be 10,000 pages of tax codes, but not for form 2290. We use the same form with the underlying model to drive the desktop appearance, the wizard appearance. Notice that all my information from the wizard is now in this traditional view. I declared UI bindings to the same underlying XForms processing model. We have some custom controls that understand things like phone numbers. For signatures, we have digital signatures using the certificates. Shows ("This is digitally signed and cannot be altered" popup on field.) The same underlying model drives all this stuff. Next button shows underlying rules in form filling in values in spreadsheet-like fashion and updating the rules for the document. It doesn't matter if I use the wizard-based version or the traditional version. Or an oral presentation -- it's the same underlying data processing model.
John Boyer (PureEdge Solutions): A container for the data, the relationships, their properties. Here is a required field which I have to either tab twice to get out of or enter data, because it is required. (Shows calculation of quantity, price, etc.) The host language extends the calculations. Our XFDL language allows you to control font color and image based on instance data. The XForms model gives us relevance -- when I select COD the credit card controls become invisible and unselectable (using XFDL to control the presentation).
John Boyer (PureEdge Solutions): We can control relevance, which controls display and interaction. There are features for dealing with dynamic data such as adding to sets.
John Boyer (PureEdge Solutions): The computations are dynamic, now it is the sum of 5 rows.
John Boyer (PureEdge Solutions): If the attachment is a picture it is visible.
Kelvin Lawrence (IBM): How are
you rendering this?
John Boyer (PureEdge Solutions): It is the PureEdge rendering agent. See for a demo.
Chet Haase (Sun): In your table
demo with rows, it repainted the entire window. Is that an
implementation detail? Was it going back to the server?
John Boyer (PureEdge Solutions): It was an implementation detail, and not going back to the server. It was an artifact of laziness in our rendering engine.
Doug Schepers (Independent):
There is no visual depiction of XForms -- it is all underlying
data? What we saw is not like HTML Forms, it is not a widget set,
right?
John Boyer (PureEdge Solutions): To some extent. XFDL as a skin means that XForms has a "input" control and the basic purpose is user-based intent for collection of data. We can wrap an XFDL field around it; where the field is, or what font to use, is controlled by XFDL. But XForms provides the model.
Micah Dubinko: These are my personal opinions, not necessarily endorsed by my employer.
Micah Dubinko: To communicate data, you need a rich addressing system. Early drafts of XForms used new inventions, but as that went through the gauntlet of W3C process, it was replaced with stuff that people already know. It started with a multi-year process.
Micah Dubinko: It needs to work with script better.
Micah Dubinko: I get email about my book with XForms that doesn't work. At least 4 out of 5 are problems with namespaces -- declared, or used with XPath. I wrote an interactive validator using RelaxNG and some document scans based on XPath. You can access this from But namespaces are a problem. Anything that comes out of the W3C will use them. In the short term, expect your users to be noticing this pain. We might be seeing some workarounds. For a longer term solution, if you are feeling this pain, make yourself heard more and take it to the highest levels in the W3C.
Micah Dubinko: I think the
direction with your suggestion is good; we could build bridges.
There is good work still to be done.
Chris Lilley: I am puzzled by why mobile developers can do selectors but not XPath?
Håkon Lie (Opera): That's like saying you have done JavaScript so you can do more.
Chris Lilley: So it's code size?
Kelvin Lawrence (IBM): Could you
say more about namespaces? It it hand coding?
Micah Dubinko: From the errors I have seen, namespace URIs are really long and you need a lot of them and you can't fit them in your head. XPath and Namespaces are a problem -- XPath doesn't use the default namespace. The boundaries between two different namespaces are also a problem.
Mark Birbeck (x-port.net): We touched on these yesterday. <p><b></p></b> Should we not insist on fixing that? We need to make it easier to author. We just have to live with namespaces. I will give Opera a hand in implementing XForms in Opera if necessary; we can knock it out in a week if XPath is the problem.
Doug Schepers (Independent): XForms is really cool. I can see what it can. What can't it do? What other components does it need for XHTML, SVG, XBL? Suspend and resume for file system is not defined. What does XForms need to be a team player in an applications framework for the web?
John Boyer (PureEdge
Solutions): Some of the things from XFDL are
incorporation of XML DSIG for hooking into other
authentication systems. Wrapping up in a compound document.
Hooking up other types of controls, like attachments. Unified
handling of attachments without having to do MIME
attachments. Font and color handling.
Steven Pemberton (W3C/CWI): We produced 1.0 and are now in requirements for 1.1. 1.0 is an 80/20 cut. 1.1 is the a standardization of extensions in existing implementations and low-hanging fruit.
Micah Dubinko: The 1.1 requirements document is published.
TV Raman (IBM): What does XForms need to be a team player? It is not a standalone vertical silo. It is a language that can be embedded in different containers. A necessary condition for doing that is that you cannot and should not specify everything. We didn't specify save and restore in the browser sandbox and in a custom container, as they are different. XFDL is a good example. You can criticize the XForms spec for this but this is a strength. Ditto for binding; XForms doesn't have a widget set. XForms has a set of abstract user interface controls; we leave how they are presented up to the implementations and the datatypes are the controls are bound to. XForms isn't yet Emacs so it doesn't solve everything... Dave alluded to this; a mechanism to bind specific themes or renderings to XForms controls is one thing that it needs. XForms spec should not specify this; Mark Birbeck uses XBL. These should be done in another specification that shows how to bring together XML, XML Events, XHTML, CSS, SVG, Voice XML, etc.
John Boyer (PureEdge Solutions): So what is enough to specify is the question -- we need to enough specified so we can design business processes around XML data.
Chet Haase (Sun): This was
partial answered, but from yesterday there is recognition
that SVG doesn't do layout, etc. From XForms I get the sense
that it doesn't do so much are you trying to be the Webapp
answer? Or are other technologies doing things and XForms and
compound documents.
John Boyer (PureEdge Solutions): That's a great question. The XFDL skin includes the ability to drop a JAR in the form to imperative extensions.
Chet Haase (Sun): So that's markup plus forms. How about multiple markup?
John Boyer (PureEdge Solutions): Host languages are providing these answers.
Micah Dubinko: XForm is the intention layer. You need something else on top of that to embody that.
Steven Pemberton (W3C/CWI): That is the same approach for how HTML was designed -- the semantics and then the presentation layered on top.
Steven Pemberton (W3C/CWI):
The stylesheet where you don't link it in the document is the
idea approach. The ideal is to bind onto XForms and not put
the forms into the language. Layer it over. Don't have SVG
elements with a forms ref, but use XBL or something to bind
the SVG onto the XForms intention language.
Chris Lilley: I see the value in that. People link to stylesheets. Suppose you had an SVG slider; keeping them separate and using binding leads you to the packaging. Historically the web sends you a root and that points you to images. We need a small manifest.
Steven Pemberton (W3C/CWI): In my 1980's system, the stylesheet had a parameter that applied to the document, not the other way around. It's much more flexible that way.
Mark Birbeck (x-port.net): ...
Peter Stark (Sony Ericsson):
We haven't focused on XForms in mobile because it doesn't
help us with games and images and entertainment, not because
of implementation complexity. We would use the input modes
system if it were a separate spec.
TV Raman (IBM): It's an appendix...
Leigh Klotz (Xerox): Let's get XML+CSS+SVG+XForms processors out there in critical mass so that we can spark adoption.
Steven Pemberton (W3C/CWI): Give
Leigh first choice?
Dean Jackson (W3C): Do you run Linux?
Leigh Klotz (Xerox): Yes.
Dean Jackson (W3C): You get one choice -- the book.
Cameron : We have profiles for XHTML+MathML+SVG, etc. But to get some extensibility, you don't want to have to construct a new browser. That's where XBL comes in. Then we have a framework. You get plugins with a blank white square, but you can't get much interaction between the different parts of the document. If everything was converted to SVG at the base level then you could put MathML in. So use XBL and make up your own elements. We need to take note of how the parent document does its layout: for example, XHTML has the CSS box model and SVG has things where you put them.
TV Raman (IBM): So you say if you
need a compound rendering model for MathML and XHTML and so on,
map it all to SVG and then use XBL. Mark Birbeck raises the
accessibility issue. If you map it to you an SVG canvas, that
just gives me PostScript + Eventing, essentially News from the
late 1980's. Do you have any thoughts about how to preserve both
DOMs? The range control in XForms that you map onto the spin dial
tells me what I need, not the SVG DOM.
Cameron : The way it was is that each element had a shadow tree attached to it, as the SVG that it equated to. The rendering could be a separate tree, but you have to keep them in sync.
David Baron: The way XBL works is
that the original DOM tree stays around. It gives you additional
content nodes and the original DOM API navigates the original DOM
tree, and a second DOM for the rendering tree with additional or
different content.
TV Raman (IBM): Then do I play Tarzan and jump from tree to tree?
David Baron: Yes, but you don't have to.
Glen Gerston (Ideaburst): The
original is not lost. In terms of layout, you mentioned XBL.
Probably declaratively, the runtime rendering engine would be
faster to handle it directly.
Cameron : Probably yes for grid layouts.
Mark Birbeck (x-port.net): On the
two trees, it's not just the shadow tree. There may be
intermediate steps, for example an abstract control. An input
control on an IP address can be four further controls that
themselves are abstract. Can that be solved with a shadow tree
storing the four inputs and then a shadow tree on each
input?
TV Raman (IBM): Recursion gets harder with the shadow tree approach.
Mark Birbeck (x-port.net): You need the abstract binding on the source side and the rendering model then itself might have a shadow tree, but that's a separate issue.
Ian Hixson (Opera Software): With XBL/RCC, we shouldn't let those technologies be a temptation to send proprietary markup over the wire; you should send XForms or whatever.
Cameron : If you have the means to convert it to what you know then what is the problem?
Dean Jackson (W3C): Thank you.
Glen Gerston (Ideaburst): Something that the user interacts with without having to go the server necessarily.
Glen Gerston (Ideaburst): Adobe sells fonts; they have to make a GIF for their type faces on a regular basis. So instead we have an app embedded in an HTML page, enter text, and a point size and get a sample. One problem is that the runtime environments don't play well with the browser. It works in IE on a PC but not on a Mac. That's a major problem.
Glen Gerston (Ideaburst): Here is an online "Adobe Arena" ticket purchasing system. It downloads data and you can roll over the sections and see what's available, or change the event. We get a running tally, and a form to buy, and then we get a printable SVG ticket. We can cut and paste directions, and zoom in on the map.
Glen Gerston (Ideaburst): We got an error because the JavaScript tried to insert into the SVG before it was rendered. We can pan and zoom without reloading, and raw on the map. We can do overlays. The artist drew this in Illustrator and the programmer hooked it up.
Glen Gerston (Ideaburst): You can't use pre-defined interfaces, so we need interface widgets. This opens in a new window, from the browser. The content resizes and we can switch tabs programmatically.
Joshua Randall (France Telecom):
Do you want these in SVG or just somewhere?
Glen Gerston (Ideaburst): We think that the SVG runtime could be made to do it but we could see it elsewhere.
Tantek Çelik (Microsoft): On the runtime environment, the standard set of widgets, do you mean semantic or visual?
Glen Gerston (Ideaburst): Visual widgets. Tree views, menus, phone interfaces, etc.
Tantek Çelik (Microsoft): Take a look at the CSS 3 basic user interface module appearance property.
Tantek Çelik (Microsoft): In the stadium example, the URL stayed the same, even from one concert to another. What if I click the back button.
Glen Gerston (Ideaburst): It goes back to the previous page.
Tantek Çelik (Microsoft): That seems broken.
Glen Gerston (Ideaburst): That's a problem of running in a web container.
Mark Verstaen (Beatware): The
look and feel of the widget has to be customizable. You enter the
framework war then. Now we have tons of frameworks from
Microsoft, Apple, and others.
Glen Gerston (Ideaburst): We would like to see even standard looking widgets, perhaps customizable with CSS. To us having some standard set of objects would be good. Our interfaces are obviously very stylized, but we could create applications.
Mark Verstaen (Beatware): Customizing a widget is not just the look; for a widget you need three animations. For a tree view, you have the mouseover effect, etc. It's endless.
Alex Hopmann (Microsoft): Raise your hand for button, checkbox, slider, date picker, etc. The spectrum is an application platform thing. Standards groups are poorly suited to come up with ones for everyone.
Dean Jackson (W3C): Let's end this.
Leigh Klotz (Xerox): The best is the enemy of the good.
Doug Schepers (Independent): SVG is a great medium to deliver WebApps. I agree with Glen that we need a set of widgets. We do not need them to be automatically provided. Even if you have sliders, do you want them left, right, top, ticks?
Ian Hixson (Opera Software): You
said that HTML and SVG didn't work together. Shouldn't you make
them interact better rather than adding the features
together?
Doug Schepers (Independent): Absolutely. With the SVG plug -in they won't work well together. Like everybody else here I want to hear that they all work together.
Chris Lilley: Adobe says that the plug-in works in some platforms but not others. Tantek said there was no W3C spec to implement it.
Tantek Çelik (Microsoft): That was a few years ago.
Chris Lilley: Is there a spec now?
Tantek Çelik (Microsoft): No.
Chris Lilley: So how can we do it?
Doug Schepers (Independent): I think we need them in SVG and we need them soon.
Steve Zilles (Independent): I am
retired from primarily IBM and Adobe but am presently an
independent consultant. I was co-chair of the XSL 1.0 WG and have
20 years experience of working with documents, and worked on HTML
and CSS, and am a document guy rather than a Web App guy. It
turns out if you want to do compound documents in a practical
way, you come back to web apps.
Steve Zilles (Independent): Compounding means a lot of things together: text+graphics+math is a simple example. Chemical formulae is another. No one vendor wants to do them all. Authors need different subsets. Compound documents inherently compound things that don't come from the same place.
Steve Zilles (Independent): The first four I already knew and the last three are new from this meeting.
Steve Zilles (Independent): An interface that, given a property provides APIs
Steve Zilles (Independent): Which document?
Steve Zilles (Independent): It is a mistake to say that any one of them is in charge. The more important question is where the capability is provided.
Steve Zilles (Independent): A two-pronged approach
Daniel Austin (Sun Microsystems): Who is in charge? Consider a set of rules associated with one of the components is in force at any time.
TV Raman (IBM): I agree that of
the things that want to be in charge, they should be
daisy-chained. In the list, though, XForms definitely does not
want to be in charge. Do you have thoughts on a VM that would be
an XML browser and could dynamically bootstrap itself, so it
wouldn't be monolithic?
Steve Zilles (Independent): No, I'm a document guy and I don't have an answer. The collected intelligence from the room does have thoughts...
Dean Jackson (W3C): We will have ten minutes per question for staged discussions and then 30 minutes of open discussions. Here are my proposals:
Daniel Austin (Sun Microsystems):
I don't agree with device specific profiles. I think we should
find the best solution to this problem, not in a way specific to
a certain class of devices.
TV Raman (IBM): I think we should factor the question of device specific profiles (a bad idea) from the low-hanging fruit of bringing together a group of W3C specs. If we don't bring them together, perforce SVG will develop little bits of XForms. etc. These two problems need to be factored.
Peter Stark (Sony Ericsson): The W3C should take the lead in showing how the SVG, HTML, and SMIL should be combined. I support that SVG/XHTML/SMIL is a pragmatic approach and an urgent need. On device specific profiles, I don't like the term. SVG, XForms, etc. should have different conformance levels so the industry can support them incrementally.
Håkon Lie (Opera): For compound documents yes, but application developers want DOM. If we do web applications, we need Turing completeness.
Jon Ferraiolo (Adobe): You have to think about who is talking -- Peter from Sony Ericsson is in the industry and has an urgent need from his industry. Others want a nice, clean architecture. Let's do that on a grand scale, but let specific industries solve their needs. As Dan said, if we don't do it, someone else will do it and W3C won't lead the web.
Mark Birbeck (x-port.net): The first task should be aggregation of what people are already trying to do. I'm not sure what a profile means, but an if it is an aggregation, yes. But then through what vehicle to bring it together? We don't know the answers, but one of the questions from before Cannes is the MIME type, for example, unmentioned this week. It isn't obvious that we will quickly resolve it. Start with the vehicle with the bigger picture, but we will address even more issues that fall out. Let's bring people together and see how problems in SVG and XForms communicate and make that a requirement for the bigger WebApps thing.
Rich Schwarzfegger (IBM): We have errata in the DOM working group. Let's fix that.
Steven Pemberton (W3C/CWI): Within W3C, DOM is a central part of our technology and not having a DOM WG is a problem. We need someone to own that space.
Dean Jackson (W3C): Should the
W3C provide a profile of XHTML, SVG, SMIL, and possibly
XForms.
Leigh Klotz (Xerox): CSS?
Dean Jackson (W3C): Should the W3C provide a profile of XHTML, SVG, SMIL, CSS, and possibly XForms.
Alex Hopmann (Microsoft): A limited restricted profile?
Dean Jackson (W3C): I don't think it means all possible variations.
Chris Lilley: All the existing proposals have taken XHTML Basic, SMIL Basic, SVG Tiny. But then in great detail for interoperability -- width and height on image, etc. The glue that is missing.
Alex Hopmann (Microsoft): That touches on what I feel, that a lot of the basic specifications are not complete yet. They don't give interoperability. We don't need a specific profile; rather, we need to get the specs of these test suites and normative detail right to solve the initial goal of interoperability.
Chris Lilley: Yes, that's necessary but not sufficient. You need to check that they do fit together.
Jon Ferraiolo (Adobe): The biggest activity would be the interoperability test suite.
Håkon Lie (Opera): The specs are done...
Tantek Çelik (Microsoft): We are missing the test suites, though. Håkon Lie (Opera): They all have good benefits; is this tiny, or what? Do we cut down or do a mega thing?
Steve Zilles (Independent): I think the main reason why a combination is important, is that despite the interest in the best working groups, there isn't sufficient time to explore the cross-WG issues. The main value is a forum for addressing the issues that go outside an individual working group's purview. For the straw vote, would the people who care about this man the working group to do this thing? It won't be individual test cases for the specs. In the property set, divergence happened because there was insufficient conversation, not malice aforethought.
Charles Ying (Openwave): I think the effort should be smaller. Test suites are an excellent start. The scope should initially deliver the integration of two fronts -- XHTML and SVG. Then we can look at next steps. That's for our market; but which standards depends on who is involved in the effort.
TV Raman (IBM): I want to re-emphasize the focus on combination and not the profile issue. There are examples of two: XHTML+ MIME document. When I wrote the XHTML+Voice profile I looked at it and it is a good document. Three gets more interesting not at the DTD or Schema level, but at the processor level. Final, let me echo Steven Pemberton and Rich Schwarzfegger's DOM issue.
Charles Ying (Openwave): Even integrating two core W3C standards (XHTML + SMIL) still needs an accurate conformance test suite and use cases. We need to solve issues like this first before addressing additional standards.
Glen Gerston (Ideaburst): Do you
mean an embed or mixed-namespace?
Jon Ferraiolo (Adobe): When I gave the Adobe position paper, I suggested that keeping it small would focus on external combinations, not inline. The external one is easier. You don't have to worry about CSS styling across boundaries, for lower-hanging fruit.
Vincent Hardy (Sun Microsystems): Look at what it takes to develop the specs. We tried to make a case about what happened with implementation complexity. Bigger profiles are harder. This is orthogonal to target devices. For SVG, Tiny is more successful because of the mobile industry, but also because the implementation barriers are lower. Still it is too high. For the WG, it is hard to get people to take minutes, do test suites, review specs, etc.
Scott Hayman (Research in Motion): I would like to echo Charles, Vincent, and Jon. Small steps. Carriers are doing it. We need five years to pull everything back together.
Dean Jackson (W3C): We couldn't vote on the straw poll because we could not define the question.
Dean Jackson (W3C): Let's suppose that a WG is chartered to examine Web Applications requirements; Steve used the phrase "virtual machine."
Daniel Austin (Sun Microsystems):
Is that the cart before the horse?
Steve Zilles (Independent): I said create an incubator group, not a working group. It is a lighter weight, for requirements, use cases, and implementations of the pieces for a more formal process.
Daniel Austin (Sun Microsystems): The first requirement for the group for requirements would be solving the compound document problem. Web Applications are the cart and Compound Documents the horse. I can have one that isn't the other. Then tackle them in the sequence we need to solve them. We can't solve the Web App problem without first solving the compound document problem.
Glen Gerston (Ideaburst): I am in
favor of a group, but 2 to 3 years won't help. We need a
specification for a runtime environment to say what it has to
pass.
Håkon Lie (Opera): Use cases is a better starting point for stakes in the ground; we need to work quickly.
Mark Birbeck (x-port.net): The compound document problem is many problems in different contexts; editing, potential shape for guiding the user. People draw a distinction between the documents and applications. There are some things such as the MIME type question, but in the main the problems are inseparable. On the Virtual Machine, I suggest that we aggregate what we already have. Take the DOM spec; it is a virtual machine. It is specified in a heavy way, as an API. I think a declarative markup version of the DOM API, as done with the XML Events specification, is a good idea. It is more manageable and easier to incorporate into other specifications. For factoring, it becomes easier to build on top of the specification. I propose only one new module, system (closing applications, clock, etc.) Everything else already has a corresponding feature.
TV Raman (IBM): There are enough Xeroids in the room to ask, is the document the interface? In 30 years will we still be asking this? We have had discussions during the W3C QA about how to write specs where the test cases drop out. So, take existing specifications such as SVG, XForms, SMIL, and stitch them together. Let's write actual angle brackets at the start, and at the end the test cases. Solve the low-hanging fruit first: MIME type, loading into a DOM, initialization, propagation of events. If solve those four, then how to package them. There is no new spec here.
Steve Zilles (Independent): My comment is on the issue of do we need to define what an application is? Or is an application different from a document? My answer is that it's irrelevant and doesn't matter. What facilities do we need to get work done? Mark just needs the facilities to write the code to get the work done, and the prospective incubator should be focused on that.
David Baron: There might be
confusion between how compound documents should work and an API
such that different programs can implement different languages
within the compound document. The DOM 2 spec says how events
propagate, and CSS says how cascading imperatives work, without
namespaces. The issues are more about the API of how to do that
with multiple implementations.
Chris Lilley: I agree; with a link sometimes, you want inheritance. Sometimes you want to stop inheritance and want a link. That's the extra bit people want.
Alex Hopmann (Microsoft): On the proposals around use cases, my concern is simple use cases. A calculator is simple, but more sophisticated things with DHTML and more complex things are what you need to demonstrate in an interoperable way. Use cases don't help there.
Mark Birbeck (x-port.net): We do have the specs for CSS etc. but they smack of a world with a monolithic browser controlling the entire environment, not for how it works with modular software. If we are happy to wait for Mozilla to implement MathML and then SVG and then XForms, OK. But people want MathML now. People want to incorporate it now. The browser doesn't provide the means to hook these things in. CSS is defined but we don't say how a module knows it is now green. Are there CSS events? A dynamic InfoSet module?
TV Raman (IBM): The cynical thing
is that we are creating open tags without close tags and an
ill-formed web. We had two discussions. What did we
conclude?
Dean Jackson (W3C): I am willing for someone to stand up and suggest a conclusion.
Philip Hoschka (W3C Interaction Domain Leader): I would recommend a straw poll on priorities on work items.
Dean Jackson (W3C): A work item?
Philip Hoschka (W3C Interaction Domain Leader): XHTML+SVG+SMIL? An incubator? MIME type for markup?
Leigh Klotz (Xerox): Note that on XHTML+SVG+SMIL the only communication with the server would be name-value pairs.
Suresh Chitturi (Nokia): Would
the complexity rise or fall when you combine documents, or keep
them separate?
Jon Ferraiolo (Adobe): So the minimal possible to meet the requirements?
Suresh Chitturi (Nokia): See what we are gaining.
TV Raman (IBM): We've had the broad brush conversation, which set of markup languages, what VM/dynamic browser. Identifying those as work items won't move us forward. Let's identify the specific items and use those to build things let people move forward. Then let a thousand flowers bloom.
Suresh Chitturi (Nokia): That's
the old idea of profiles. We need a specification for the
profile.
Chris Lilley: You need test cases. The mobile profile really does exactly what they agree to.
Daniel Austin (Sun Microsystems): If we go down this path of specific profiles, we will wind up with an addition to the ad hoc solutions. And we have a Note for these already (XHTML+MathML?). Are we going to proliferate the number of ad hoc solutions?
Mark Verstaen (Beatware): The
question is not will there be a profile, but will they the W3C
have a XHTML+SVG profile? It will be shipping regardless.
TV Raman (IBM): If it's shipping in October, does the W3C need to?
Chris Lilley: Vodaphone has four tiers of phones. The top three will ship with SVG and XHTML in October. We don't want "Select Vodaphone Profile."
Rich Schwarzfegger (IBM): Do the
authoring tool up front and put it in your plan.
Jon Ferraiolo (Adobe): There are authoring tool vendors in the room. What percentage of HTML is authored by hand? You can do markup for flowing text and it works OK but more visual stuff...as in the mobile space, you need tool involvement.
Rich Schwarzfegger (IBM): Why can't I just draw this? How do I pull it all in together? How do I make that easy?
Mark Verstaen (Beatware): There are tools, drag and drop re-use, creation, etc. You need to specify the profile today (Nokia, Sharp, etc.) The way that bitmap fonts is not the same, focus across languages is not the same. We solved this problem in my company and can make money, but we don't think it's the right way.
Dean Jackson (W3C): (writes) "Develop a specification that combines "profiles" of W3C Technologies, primarily focused at the mobile market space with a conformance test suite." I've not added conformance levels (Tiny, Basic, etc.)
Dean Jackson (W3C): Show of hands
for Good Idea and Willing to Participate?
Robin Berjon: And opposed?
TV Raman (IBM): And how about XHTML + SVG + XForms?
Steve Zilles (Independent): If you form a group, the group should decide.
TV Raman (IBM): Let's solve the problems that enable these.
Dean Jackson (W3C): The group can decide once created.
Tantek Çelik (Microsoft): The use case is not acronyms.
Jon Ferraiolo (Adobe): Let's go to the second one first:
Dean Jackson (W3C): (writes) Charter a (incubator) group to address:
Jon Ferraiolo (Adobe): Two groups
in parallel. So what Steve Zilles suggested...
TV Raman (IBM): If there are two groups, the short term has no guarantee to produce something compatible with long term.
Joshua Randall (France Telecom): You don't know the MIME type for XHTML+SVG, but let's stay away from specific mobile problems and solve generic compound document issues generically.
Alex Hopmann (Microsoft): How
open-ended it is makes a difference for me. The mobile guys say
that the specs are there but they need details about how to hook
them together. You didn't mention ECMAScript or DOM so you're
talking about the content space.
Dean Jackson (W3C): Yes.
Alex Hopmann (Microsoft): And add CSS.
Mark Birbeck (x-port.net): I think we should narrow this first task and not make the web applications work depend on it. We are requested to solve a specific problem of October in the mobile space. Just say there is an XHTML+SVG MIME type with a long name: application/xml+svg+xhtml, define a Schema that mixes them, and ship it. We don't pretend that it feeds into web applications, and separate the issue.
Robin Berjon: It's not just document -- SVG Tiny supports MicroDOM. Right now mobile stuff is entertainment. With more DOM and more information I would spend more money. It should be a strict profile, with exact user agent specifications.
Jon Ferraiolo (Adobe): Yes,
Suresh, can you list the companies who standardized the MicroDOM:
Nokia, Sony Ericsson, Sun, IBM, etc. There is a large area of
interest in scripting on mobile devices from big players. On the
MIME question: Vodaphone is assuming that there is an outermost
document type, .HTML or .SVG. You don't need a new document type.
HTML Object or SVG foreignObject. But Vodaphone doesn't do the
SVG foreignObject, just standalone SVG.
Steven Pemberton (W3C/CWI): So why do we need a spec?
Jon Ferraiolo (Adobe): Vodaphone has a 25-point list they want to give to the W3C.
Mark Birbeck (x-port.net): Is the object tag the only way? How do you get an A inside SVG?
Jon Ferraiolo (Adobe): If you want to see the the SVG document you click on it.
TV Raman (IBM): IF you look at the two extremes, for October, an XHTML+SVG thing that says how to combine, MIME type, syntax, Schemas, that doesn't need a WG. That is a W3C Note. Especially for October. But ensure that what it submits is an XML Instance not a name-value pair. That will give you longevity. Let's not do the 1994 kludge of name-value pairs.
Tantek Çelik (Microsoft): A quote: "What not to email. Email is safe unless it contains programs. Data and documents are fine. If you send me a program I will not read it." Tim Berners-Lee. Now, note that at the highest levels of the W3C the difference is acknowledged.
Robin Berjon: Nobody said there was not a distinction.
Tantek Çelik (Microsoft): Steve did.
Joshua Randall (France Telecom): The WD for August 2002 for XHTML+SVG+MathML. Isn't it already it?
Jon Ferraiolo (Adobe): It is just the syntax.
Chris Lilley: No, that is the horrible but necessary DTD modularization validates. It proves that DTD modularization works. It does not give you a working document.
Daniel Austin (Sun Microsystems): It works on the screen.
Chris Lilley: ...
Mark Birbeck (x-port.net): I see -- Masayasu asks who gets the event when you click; SVG or XHTML.
Unidentified Speaker: Let's try to get a conclusion here.
TV Raman (IBM): Jon, the problem
is that you wanted by October is not simple any more. When you
add SMIL you need to solve it again. You can get a W3C note by
October though.
Jon Ferraiolo (Adobe): A clarification. The Vodaphone thing is locked; they do not want the W3C to take it over; they want it taken over by a standards organization going forward. There is no imperative on the W3C to do a profile within six months. But a following Spring or Fall 2005 thing is something the W3C could take on and might represent low-hanging fruit.
TV Raman (IBM): Is it a six month or 12 month deadline? In 18 months we can do the right thing.
Steve Zilles (Independent): A
third question: If there is to be a profile, who thinks it should
be done in the W3C?
Dean Jackson (W3C): 19 Elsewhere? 0.
TV Raman (IBM): Attach a timeline.
Dean Jackson (W3C): ASAP? 21? Ad not ASAP? 0?
Dean Jackson (W3C): Based on that feedback of a majority, I believe that the W3C could take the next step to propose a charter and let the membership and public comment.
Suresh Chitturi (Nokia): I want
the W3C to ensure that OMA and 3GPP endorse it.
Chris Lilley: I agree and we have relationship with 3GPP and are building with OMA.
TV Raman (IBM): Do these need to be working groups or just notes?
Dean Jackson (W3C): Thank you very much Raman; good feedback.
Dean Jackson (W3C): At W3C? 23?
Not at W3C? 2.
Dean Jackson (W3C): ASAP? 23? Not ASAP 2.
Ian Hixson (Opera Software): Both HTML 4 and XHTML 1 and any level of CSS.
Dean Jackson (W3C): We've just
voted on a group to examine use cases and this sounds like a use
case.
Tantek Çelik (Microsoft): You haven't asked good enough questions for at least half the room.
Alex Hopmann (Microsoft): There are about 46 people in the room and about half of them didn't vote. I think that's not an overwhelming interest.
Robin Berjon: That's a pretty good vote for a standards organization.
Alex Hopmann (Microsoft): Of a two day workshop?
Jon Ferraiolo (Adobe): Relative to the binary workshop?
Robin Berjon: In the binary workshop it was 30% or interest, and now we have an active WG. This sounds like a fairly good commitment and fairly overwhelming interest.
Chris Lilley: The formal commitment can come only from AC Reps.
Dean Jackson (W3C): Leigh has taken minutes. Leigh's minutes are going to be the official ones. How should we validate that the minutes are correct?
Steven Pemberton (W3C/CWI): As long as they are posted as draft, then it's fine and after a week they are public.
Dean Jackson (W3C): Who does not want Leigh to post the draft minutes to the public list and then declare them final one week later? No objections.
Action 2004-06-2.1: Leigh to post draft minutes to the public mailing list.
Alex Hopmann (Microsoft): (leaves)
Action 2004-06-2.2: Dean to finalize minutes one week after workshop.
Kelvin Lawrence (IBM): At the 50,000 ft level, I think there is a danger we can get fixated on what we can do as technical guys who can write spec. We can pick some MIME types, but we should be talking about industry interoperability events to get people together.
Daniel Austin (Sun Microsystems): We should properly divide up our problems with the W3C Processing Model group. We don't want them to get too far down and ambush them. Let's make sure this activity is well advised of what we intend to do.
Dean Jackson (W3C): For XHTML and HTML, and every DOM level, who believes "Develop declarative extension to HTML and CSS and imperative extensions to DOM, to address medium level Web Application requirements, as opposed to sophisticated, fully-fledged OS-level application APIs."
Dean Jackson (W3C): For 8,
against 11.
Kelvin Lawrence (IBM): Example?
Ian Hixson (Opera Software): The Opera Web Forms 2 proposal. One example would be to add a required attribute to the input element.
Tantek Çelik (Microsoft): This proposal mixes a lot of things that people want and don't want.
Dean Jackson (W3C): For XHTML and HTML, and every DOM level, who believes "Develop declarative extension to HTML and CSS and to address medium level Web Application requirements, as opposed to sophisticated, fully-fledged OS-level application APIs."
TV Raman (IBM):.
Dean Jackson (W3C): For XHTML and HTML, and every DOM level, who believes "Develop declarative extension to HTML and CSS and to address medium level Web Application requirements, as opposed to sophisticated, fully-fledged OS-level application APIs."
Dean Jackson (W3C): 8 for, 14 against.
Dean Jackson (W3C): Thank you to
Adobe for providing the room and food.
Chris Lilley: Thanks to Dean Jackson for doing a great job.
Dean Jackson (W3C): I will be bugging you to get the slides. I will send one more spam when the meetings are complete.
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Of course, these assumptions may or mayn’t be verified on your target platform and it is important to assess the goodness of any optimization with a stopwatch in hand—anyway, more on this later. Let us come back to our shifts.
Let’s say we want to multiply 16 bits integers by
. This isn’t a nice fraction we can replace by a simple shift right away; it’s conspicuously not a simple power of 2. But it’s a series of sums of power of two. Indeed, if we look at it differently,
To each 1 in the binary expansion of
corresponds a shifted value of
:
Which suggests the direct (but naïve) approximation (x>>2)+(x>>5)+.... That actually works, but may not be very precise because bits that should contribute to the sum get shifted out. C shift operators will just truncate the fractional bits—it’s an integer operation, after all—so you loose bits that should contribute to the sum. The first impression is that it’s just a rounding error (meaning, the last bit or so) but it may yield a large error.
The second thing you may try is to scale x before shifting. One way of doing a ‘free’ scaling is to use a trick similar to what I used for an alternative line algorithm. That is, we’ll use the language to have a shift free scaling:
typedef union { // endian-dependant! struct { uint16_t lo, hi; }; uint32_t s; } fixed_t;
Using this structure, setting lo to 0 and hi to
x promotes x to a 32 bits version shifted by 16 bits. The
whole method could look like:
inline int shifts_more(uint16_t x) { typedef union { // endian-dependant! struct { uint16_t lo, hi; }; uint32_t s; } fixed_t; fixed_t scaled={0,x}; // C99 extensions? fixed_t sum={0}; sum.s+=scaled.s >> 2; sum.s+=scaled.s >> 5; sum.s+=scaled.s >> 8; sum.s+=scaled.s >> 11; sum.s+=scaled.s >> 14; // the next one, >> 17, gives zero! return sum.hi; }
Using this version, all bits contribute to the results and the (relative) error is reduced to its minimum. We could have used an actual shift rather than an union:
inline int shifts_less(uint16_t x) { const int scale=4; uint32_t sx = (x << scale); uint32_t s=0; s+=sx >>= 2; s+=sx >>= 3; s+=sx >>= 3; s+=sx >>= 3; s+=sx >>= 3; return (s>>scale); }
Where you can control time versus precision by changing the value of scale. Or you can look at it the other way ’round:
inline int shifts_left(uint16_t x) { int tx=x; // promote to 32 bits int s=tx; // 14 s+=(tx <<=3); // 11 s+=(tx <<=3); // 8 s+=(tx <<=3); // 5 s+=(tx <<=3); // 2 return (s >> 14); }
Or you can use an integer multiply:
inline int shifts_mult(uint16_t x) { // 01 0010 0100 1001 = 0x1249 return (int(x) * 0x1249) >> 14; }
So which one’s better? Precision-wise, they’re all the same, except for the naïve version that has a higher error and for shift_less that depends on a scaling constant. On all 16 bits integers, the average error (difference between the float version and the integer version) is given by:
So the other methods have basically 10 times smaller errors. Which is good. What about speed? Well that’s where the catch is. Let us compare, again, g++ against icc, the two compilers I use. On a T9600 Core2 CPU (the one from by Macbook Pro), the times (in micro-seconds by 65536 calls):
Let’s see what we have here. G++ seems to be a bit more efficient than icc on these series of tests. The Float method is merely using a float to perform the multiply and truncating to int, and is included as a fair comparison, the control. The Mult method is also the same using both compilers, unsurprisingly, they generate exactly the same code. G++ has the clear advantage for the Left method. Why? What happened?
Examining the code, we make a stunning discovery. Icc generates the following:
<_Z11shifts_leftt>: 0f b7 c7 movzx eax,di 8d 14 c5 00 00 00 00 lea edx,[rax*8] 03 d0 add edx,eax 89 c6 mov esi,eax c1 e6 06 shl esi,0x6 03 f2 add esi,edx 89 c1 mov ecx,eax c1 e1 09 shl ecx,0x9 c1 e0 0c shl eax,0xc 03 f1 add esi,ecx 03 c6 add eax,esi c1 e8 0e shr eax,0xe c3 ret
which is somewhat expected, while we don’t know why it prefers to do long shifts rather than a series of shorter shift lefts. Gcc figured it out a lot better:
<_Z11shifts_leftt>: 0f b7 c7 movzx eax,di 69 c0 49 12 00 00 imul eax,eax,0x1249 c1 f8 0e sar eax,0xe c3 ret
(the thing I can’t explain right now is why the shifts_left version and the shifts_mult version, which compiles to the exact same code, have different timings; and it’s not OS noise because the timings are quite different and the results are repeatable).
Despite GCC generating the same code on my AMD4000 box (yes, I know, I should get a newer computer), the run-time characteristics are quite different. Of course, it is slower, but the float version us much slower, about twice the time of More.
*
* *
So what is the morale of all this? First, don’t trust your compiler. The “optimizing” compiler didn’t optimize all that well, but the “non-optimizing” compiler did. Second, implementations that you think are roughly equivalent may be quite different speed-wise, such as, say, the Less and Left methods; turns out Left is much faster with both compilers. Third, test on the target platform(s), you may be surprised.
Nice article.
Are you compiling with gcc with -m32?
With -m32, I see the same performance for shifts_left and shifts_mult. Otherwise when I compile it replaces the function call with inline MMX ops, and gcc seems to optimize differently between the two functions.
No, I used -m64 (all my machines are in 64bit mode). You also have to be careful about those results (and I mention it in the post as the final warning) : they’re quite sensitive to the machine you will use. AMD64 (the AMD4000+) vs T9600 (Intel Core2) will exhibit different run-times because beyond their GHz difference, their execution engines are different.
Probably that using your processor I would observe exactly what you describe. What CPU are you using?
Core i7 (Xeon 3580) 3.33 GHz
Calling GCC a non-optimizing compiler is not really correct. It is a bit weaker in its instruction selection and (obviously) in knowledge of the microarchitecture, and loop optimizations are worse. Also, GCC only had link-time optimization in GCC 4.5 while icc had it for a while (this is probably the reason why it beat GCC on quite a few benchmarks).
However, the scalar optimizations of GCC (arithmetic simplification, elimination of C++ abstraction penalty, jump threading) are _very_ good and _very_ hard to beat. If the best implementation is a multiply, but your scalar optimizations cannot transform shifts into multiplies, a perfect knowledge of the core will not help.
Besides, microarchitecture knowledge is easy to add to GCC when bugs are reported that hint to the problem. It’s unfortunately a slow process, because usually it’s found by chance when an older version generated the better code for some mysterious reason. However, it does happen.
You’re quite right… I should have written “non-optimizing” with ironic quotation marks. I’ll fix that right away.
So, the next question is: what IS the process in the GCC/G++ community to include micro-architectural details?
Microarchitectural details that are public are already in, usually.
For the others, since we don’t have a crystal ball :) the easiest thing to do is to find some code where a small, apparently innocuous assembly change has a big performance impact. We can then instruct GCC to favor the better code, usually with some tweak to the backend or a new peephole optimization. As I said, most of the time these reports come from comparison with older versions of GCC when the newer version regresses.
See for example (just one comment in a huge audit trail). A similar peephole is now in for SSE too.
Although I have read the above comments and noted your correction that now refers to GCC as a “non-optimizing” compiler, I’ve never before heard it described so, “ironically” or otherwise.
GCC has always been an optimizing compiler, right from the first beta release in 1987:
And of course, there have been 23 years of further improvements made since that time. There are very few compilers that are competitive with GCC in the realm of code quality/optimization. Therefore, it should not be surprising to find that GCC produced superior results in this test. Of course, ICC is also an excellent compiler and might perform better on other tests — no compiler has a monopoly on good optimizations.
I am aware that all mainstream compilers are “optimizing compilers”, but ICC, for example, claims to be better at it, and, on the average, it is confirmed by my observations; code compiled using ICC is often faster, sometimes slower. That’s not to say that gcc/g++ is a bad compiler, quite the contrary: I think it’s a world-class compiler.
I wonder if someone did a really comprehensive survey on the code generated from different compilers… I have heard that the last few version of the Microsoft compiler is also quite good, although I did not have a chance of testing it (not my work environment).
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This document contains the C++ core language issues for which the Committee (J16 + WG21) has decided that no action is required, that is, issues with status "NAD" ("Not A Defect"), "dup" (duplicate), "concepts," WG21 N3290._.
This issue is for tracking various concerns that are raised in paper N3057.
Rationale (August, 2010):
The paper was voted in in Pittsburgh.
2..3 .3 [basic.scope.local])) shall not be used to declare an entity with linkage.to:
A name with no linkage (notably, the name of a class or enumeration declared in a local scope (3.3.3 ...
Rationale (August, 2011)
This is an editorial issue that has been transmitted to the project editor....
5.1.2 [expr.prim.lambda] paragraph 2 says,
A closure object behaves as a function object (20.8 [function.objects])...
This linkage to <functional> increases the dependency of the language upon the library and is inconsistent with the definition of “freestanding” in 17.6.1.3 [compliance].
Rationale (July, 2009):
The reference to 20..14.2 [lex.icon] : No mention of true or false as an integer literal.
From 2.14.
Note (March, 2008):
This issue should be closed as NAD as a result of the rewrite of 5.19 [expr.const] in conjunction with the constexpr proposal.
Rationale (August, 2011):
As given in the preceding note...6.1.1 [new.delete.single] par 2, and 3.7.4 [basic.stc.dynamic] par 2-3. I don't see anything explicitly saying that the replacement function may not be inline. The closest I can find is 18.
Rationale (August, 2011):
The requirements apply to definitions, not declarations..++..
7.3.1.2 [namespace.memdef] paragraph 3 is intended to prevent injection of names from friend declarations into the containing namespace scope:
If a friend declaration in a non-local class first declares a class or function).
However, this does not address names declared by elaborated-type-specifiers that are part of the friend declaration. Are these names intended to be visibly injected? For example, is the following well-formed?
class A { friend class B* f(); }; B* bp; // Is B visible here?
Implementations differ in their treatment of this example: EDG and MSVC++ 8.0 accept it, while g++ 4.1.1 rejects it.
Rationale (July, 2009):
The current specification does not restrict injection of names in elaborated-type-specifiers, and the consensus of the CWG was that no change is needed on this point...
The [[noreturn]] attribute, as specified in 7.6.3 ..
According to 8.3.4 [dcl.array] paragraph 1,
In a declaration T D where D has the form
D1 [ constant-expressionopt ] attribute-specifier.5.3 [dcl.init.ref] paragraph 3 for function types.
Rationale (March, 2011):
The functionality of the auto specifier was intentionally restricted to simple cases; supporting complex declarators like this was explicitly discussed and rejected when the feature was adopted....
According to the logic in 8.5.3 [dcl.init.ref] paragraph 5 as follows:
...
If the initializer expression is a string literal (2.3 current wording of 9..)
Note (March, 2008):
This issue was resolved by the adoption of paper J16/08-0054 = WG21 N2544 (“Unrestricted Unions”) at the Bellevue meeting.
Rationale (August, 2011):
As given in the preceding note.?
Rationale (July, 2008):
The wording in 9 [class] paragraph 10 (added by the resolution of issue 284, which was approved after this issue was raised) makes the example ill-formed:.6 [class.paths].
11 a friend..
Inheriting constructors should not be part of C++0x unless they have implementation experience.
Rationale (March, 2011):
The full Committee voted not to remove this feature....
Issue 1:
14.5.
Additional note (April, 2011):
These points appear to have been addressed by previous resolutions, so presumably the issue is now NAD.
Rationale (August, 2011):
As given in the preceding note..
Rationale (August, 2011):
The specification is as..11 ..11 .
The grammar for member-declaration in 9.2 [class.mem] does not allow an alias-declaration as a class member. This seems like an oversight.
Rationale (August, 2010):
This issue is a duplicate of 924..
Consider the following example:
struct B { void f(){} }; class N : protected B { }; struct P: N { friend int main(); }; int main() { N n; B& b = n; // R b.f(); }
This code is rendered well-formed by bullet 3 of 11.2 [class.access.base] paragraph 4, which says that a base class B of N is accessible at R if
R occurs in a member or friend of a class P derived from N, and an invented public member of B would be a private or protected member of P
This provision circumvents the additional restrictions on access to protected members found in 11.4 [class.protected] — main() could not call B::f() directly because the reference is not via an object of the class through which access is obtained. What is the purpose of this rule?
Rationale (April, 2010):
This is a duplicate of issue 472...
Rationale (August, 2011):
This issue duplicates issue 455...10 .
C1 and C2 should be effective class types (cf 5.5 [expr.mptr.oper] paragraph 3.
Also, should the relationship between those two classes be expressed as std::SameType or std::DerivedFrom requirements?
Is it possible to export a concept map template? The current wording suggests it is possible, but it is not entirely clear what it would mean.
Notes from the March, 2009 meeting:
Export is only useful for non-inline function templates and static data members of class templates, so it does not make sense to export a concept map template..)
Consider the following:
namespace N { struct A { }; template<typename T> T func(const A&) { return T(); } } void f() { N::A a; func<int>(a); // error }
Although argument-dependent lookup would allow N::func to be found in this call, the < is taken as a less-than operator rather than as the beginning of a template argument list. If the use of the template keyword for syntactic disambiguation were permitted for unqualified-ids, this problem could be solved by prefixing the function name with template, allowing the template-id to be parsed and argument-dependent lookup to be performed.
Rationale (July, 2009):
This suggestion would need a full proposal and discussion by the EWG before the CWG could consider it. the EWG.
auto and lambda return types use slightly different rules for determining the result type from an expression. auto uses the rules in 14.8.2.1 [temp.deduct.call], which explicitly drops top-level cv-qualification in all cases, while the lambda return type is based on the lvalue-to-rvalue conversion, which drops cv-qualification only for non-class types. As a result:
struct A { }; const A f(); auto a = f(); // decltype(a) is A auto b = []{ return f(); }; // decltype(b()) is const A
This seems like an unnecessary inconsistency.
John Spicer:
The difference is intentional; auto is intended only to give a const type if you explicitly ask for it, while the lambda return type should generally be the type of the expression.
Daniel Krügler:
Another inconsistency: with auto, use of a braced-init-list can deduce a specialization of std::initializer_list; it would be helpful if the same could be done for a lambda return type..
)); }
(See also library issue 2068.).
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Welcome to bull country
Have investors grown more courageous, or just more foolish? The outlook for the world economy may turn on the answer—and that depends on an elusive measure known as the “equity premium”
EVERY day, it seems, another official joins the throngs who are warning the western world about overvalued stockmarkets. Even cautious central bankers have been speaking out. Alan Greenspan, chairman of America's Federal Reserve, has mostly kept his counsel since the markets rudely ignored his mutters, 18 months ago, about “irrational exuberance”. But recently Hans Tietmeyer, president of Germany's Bundesbank, joined the doom merchants, promising that a gathering of central bankers this week would discuss the problem “intensively”. And the International Monetary Fund has also declared that stockmarkets should be watched carefully.
Investors seem singularly unimpressed. The lead continues to be set by Wall Street, whose bulls have driven American share prices ever higher into the stratosphere. The Dow Jones Industrial Average hit a new all-time high of 9,246 on July 14th; European markets were not far behind. Triumphant bulls have come up with many different explanations for the markets' exuberance. America's corporations have discovered new, world-beating skills; the computer age has created a wholly different economy; the Asian crisis means money is desperately searching safer havens; or, in a nod to those central bankers, monetary policy has killed inflation and even the business cycle. Yet none of these has converted the doomsters.
So now a new explanation is on offer. The key to Wall Street's continuing miracle, bulls have started arguing, is more enduring even than their other claims: the new courage of small investors. The suggestion is that the rules they have followed in the past may no longer apply. Having overcome a previously irrational fear of the risks of equities, they are now pouring into them. And since their enlightenment is irreversible, the bulls conclude, the trend should continue indefinitely.
Although most popular in America, this argument is starting to be heard elsewhere too. Fund managers in Europe may be impressed by America's low unemployment and high growth. But what they most want to borrow from across the Atlantic is the apparent change in investors' attitudes. If governments would get out of the pension business and investors could be persuaded to buy more equity mutual funds, Europe could enjoy a similar bull run to Wall Street's. Indeed, optimists believe that the recent run-up in European shares—they have mostly outpaced America's this year—shows this is already happening.
Of course, there are still bulls who prefer to justify high share prices in traditional ways, predicting rampant growth in profits far into the future. But as America's expansion starts to stutter, these claims are wearing thin. The total value of American equities is now $12 trillion—double the level of two years ago—but profit growth has been slowing sharply. Thus the new reliance on investors' changed attitudes. The message is: forget the New Economy; say hello to the New Investor.
Returns to go
It is not just giddy portfolio managers who herald the New Investor's arrival. As with most financial fashions, this one claims support from economists as well. They may use different jargon. But their belief in the New Investor is just as strong—perhaps because they have spent so long trying, and failing, to understand the old one.
The reason for their confusion is something called the “equity premium”. In essence, this is the average extra return (including dividends and capital gains) that investors expect to earn above that on safer investments—such as American Treasury bonds—if they invest in riskier equities instead. This number, which can be thought of as the current price of risk, has a huge influence on share prices.
The equity premium has particularly troubled economists since 1985, when Rajnish Mehra and Edward Prescott published a paper* arguing that it was too big to be consistent with prevailing theories. They assessed this by looking at almost a century of returns for American stocks and bonds. After adjusting for inflation, equities had average real returns of around 7% a year, compared with only 1% for Treasury bonds—a 6% equity premium (see chart 1).
From the July 18
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Here, I present a small class library and a set of examples for developing multithreaded programs based on
Windows.Forms. This article focuses on three issues:
Forms are run in.
The examples here all use a shared data approach to communicate between the worker and the listeners, who in these examples are
Forms. In this pattern, the worker writes results into the shared location, signals the listener, and goes on with its work. The listener at some later time responds to the signal and looks at the shared location for anything that may interest it. Because data flow is largely one direction, from the worker thread to the owner or listener, this pattern resembles a producer-consumer using a mailbox. The examples demonstrate how to synchronize access to the shared data.
If you were so inclined (evil), you can put code that takes hours to complete in an
OnClick event handler. Such a design will kill the user interface, UI, for the duration of the task, and while it is a bad design, is not wrong, i.e. it will work. With this bad design, the user will have to Ctrl-Alt-Del to stop your program. The user frustration such designs provoke will bring you a lifetime of bad karma. One of the advantages of moving a long task into a worker thread is that the UI can contain a Stop button. With the task in a separate thread, you do not kill the UI that runs in the main thread, and a Stop button will be operable at the same time the thread is running. (Please, nobody comment about using
PeekMessage or other message queue monstrosities.) In the examples, I have tossed in a
RunStopButton control that you might find useful in your projects.
With the background task now executing in a worker thread, and a Stop button on the form, we are able to stop the worker thread. There are two approaches to stopping a worker, cooperatively or with malice. The examples show a common approach to cooperatively stop a thread that uses two signals: one from the owner requesting the thread to stop, and a second from the thread acknowledging that it has stopped. The method of terminating a thread with malice is the
Abort() method provided by the .NET API. The framework provides an ability for the thread to detect the
Abort and try to exit cleanly, but I still judge this method to be only a fallback to use when the thread refuses to cooperate.
The main stumbling point to using WinForms and threads together is a critical issue about the UI: only the thread that creates a form can use the form. Commonly, the main thread creates all your forms, which implies that only the main thread can access any of the forms. At first glance, this seems to defeat one of the main uses of threads: often you split long execution time sections of code out of the UI into worker threads to keep the UI alive. The key to this problem is how to fire events from one thread back into the main thread. There are other articles discussing this detail, here I just implement in a reusable class.
Note: if you try to access a
Form from another thread, you may get lucky and see your code work as you expected and contrary to the exclusion stated in the docs. Rest assured if you are such a lucky person, that luck will expire at the most inopportune moment (see Murphy's Law: Whatever can go wrong, will go wrong, and at the worst possible moment).
The project H5ThreadLib builds a class library for use in multithreaded programs. The
Hangar5.Threading namespace contains the few classes used as the basis for all the examples. There are two main sections in this library: the thread and the controller. The UML diagram below outlines the first section.
ThreadBase is an abstract class to use as a base for all threads and uses a standard event/delegate for signaling changes or progress.
StopRequestException is a custom exception used to indicate the cooperative request for the thread to stop.
SharedData is a base class for providing synchronized access. The
ThreadBaseData class provides some standard shared data members for
ThreadBase.
To make a worker thread using this library, you make a derived class from
ThreadBase. To implement your class, you just implement
Run() similar to the Java
Thread class. The base class implements some standard start/stop behavior in
RunOuter that is required by the controllers discussed in the next section. To be well behaved, your
Run() method only must do two things:
FireStatusTickwhenever changes have occurred that you would like other objects to know about.
Wait()instead of
Sleep().
The threads use only the one event for all signaling. The event contains very little data, mostly the current running/stopped state of the thread. It is intended to be just a notification that changes are available in the
SharedData and that something may want to come and take a look. As such, this event does not need to be redefined for different applications.
The
Wait method in the
ThreadBase class is the key to stopping your thread in a cooperative manner. It should be used anyplace
Sleep() would be used and sprinkled within long loops. The method is implemented as a
WaitOne call on a
ManualResetEvent:
protected void Wait( int nMs ) { if( basedata.signalStopRequest.WaitOne( nMs, false ) ) { throw new StopRequestException(); } return; }
The
signalStopRequest is the event that the controller will set if some other party requests the thread to stop. The usage here is backwards from typical in that mostly we expect that the timeout limit will be reached because the event was not set. Thereby, the
WaitOne call will block for the timeout period and then return
false. If the event is set on entry to the method or is set anytime during the
WaitOne call, the exception is thrown to interrupt the worker thread.
If your thread code is nothing but a huge calculation loop, you can scatter in calls to
Wait() to allow the thread to be interrupted. For example:
const int chunk = 1000; int i, j; i = 0; while( i < 1000000 ) { Wait(0); for( j=0; j<chunk; j++ ) { /* do something */ i++; } }
It is up to you to determine how frequently to check. The basis for the decision is knowing how patient your users are. Even if you place no
Wait() calls, the terminate with malice approach will still be able to stop your thread.
The base class contains standard behavior for the
StopRequestException, so your code does not have to contain a
catch clause for the exception. If there is something particular your code wants to do when
StopRequestException is thrown, it can catch this exception and is required to re-
throw it. The examples demonstrate this.
Just using the
ThreadBase class has only addressed part of the issues: stopping the thread is half implemented and the beginnings of the notification scheme are implemented. But the events thrown here have the problem discussed in the Introduction.
In the pattern I use in this article, all data members that may be shared with other threads are factored out into a separate class. You could write these as members with public accessors of the thread class itself. I use a class derived from
SharedData largely as a way of focusing attention on the data members that may be shared and require synchronization. Any members that will be shared between the worker and other threads are placed in this object and need to:
It is so trivial to synchronize access, that it is hard to imagine a situation where you would use b). The separate class for the shared data members also provides a useful design flexibility. The owner of the worker thread can retain the shared data after the worker is done. You can think of this as a teacher giving a quiz to a student, at the end of the period the student gives back the quiz and leaves, and the teacher still has the quiz.
For each thread class you write, a matching thread data class derived from
SharedData will be required. The thread data class will contain probably just properties and accessor methods. To synchronize access to the data, use a matched pair of calls,
ReaderLock()/
ReaderRelease() for getter methods, and
WriterLock()/
WriterRelease() for setter methods. For example:
public class ThreadXData : SharedData { public string Message { get { string sRet; ReadLock(); sRet = sMsg; ReadRelease(); return sRet; } set { WriteLock(); sMsg = value; WriteRelease(); return; } } protected string sMsg = ""; }
shows a simple thread data class with one string property. To get the string, lock it, make a copy, and unlock it. The read lock will prevent any writing to the string while the copy is made. To set the string, lock it, write the value, and unlock. Because this pattern is common, the base class has convenient functions that reduce the typing to:
public class ThreadXData : SharedData { public int Complete { get { return LockedCopy( ref nPercent ); } set { LockedSet( ref nPercent, ref value ); } } protected int nPercent = 0; }
The examples demonstrate a few other types of accessor functions and the same lock/release usage.
A key simplicity to the
SharedData class is that only one mutex/lock is used for access to all the members. One common example of deadlocks in multithreaded code is blocking on two or more mutexes: one thread locks B and is interrupted, a second thread locks A then tries to lock B and is blocked, the first thread continues and tries to lock A resulting in a deadlock (this is the copy operator problem). By using just one lock in
SharedData, the complexity of the cases that you have to consider is greatly reduced.
Be aware that this deliberate coarse grain access for the entire
SharedData class means that all the members are locked at once. So, if the worker is writing to variable
x, the owner cannot read variable
y. You may worry that threads will be unnecessarily blocking waiting for access to the data members and your program will suffer a performance hit. I would argue that in this pattern, the probability of that are low for two reasons. First, these examples are talking about user interface updates - not game development. There is no reason to have screen updates occur at frequencies above a few times a second, if even that. The duration of holding a lock should be very low. All you are doing in the data member accessors is an assignment and return. With GHz processors, an assignment
x=bla should take a fraction of a microsecond. Comparing the frequency of the UI updates with the interval the locks are held, the probability two threads will collide is low. Second, the nature of worker threads and UIs tend to be largely producer consumer patterns. The events loosely serialize the actions such that the worker writes some results and the UI comes along and reads the results. For applications where these two cases hold true, a single lock will perform well.
Hopefully, the
SharedData class and the examples show that providing synchronized access to data is quite straightforward. To be complete, the library needs one more piece to handle the issue with events.
The diagram below shows the two controller classes that are provided to control the thread and to handle the events from the thread.
These two classes can control any class derived from
ThreadBase. They provide the typical
Start() method and a few stop methods:
Stop- uses the cooperative method of stopping the thread provided by the base class.
Abort- uses the .NET API
Abortmethod to terminate the thread with malice.
Terminate- stops the thread by first trying
Stop, and if the worker thread is not cooperative, tries
Abort.
The interesting role of the controllers is to forward the events from the thread to other destinations, referred to as listeners. In this library, listeners must be
Controls and typically are
Forms. The SingleSink controller accepts only one listener and the MultiSink controller allows for any number of listeners. Listeners register themselves with the controller by providing a
Form and a delegate. In both cases, the controllers receive the event from the worker thread and forward to the listeners.
Although you may want to, you cannot have a thread fire events through the standard event/delegate approach. This limitation is imposed by the
Windows.Forms framework that requires that only the thread that creates a
Form can use it. This same limitation exists in C++ and MFC applications, so it is nothing new. For example, if you where to fire an event from a worker thread to a delegate in a
Form to change some text, that delegate would be executing in the context of the worker thread.
BeginInvoke() is the solution to this problem as it does not immediately execute the delegate, but instead causes a message to be placed in the receiver's message queue. The message receiver then, at a later time, executes the delegate in its own thread context. For those with a Win32 API background, this solution is the same as using a
PostMessage to put an event into another window's queue. The
FireStatusTick methods in the two controllers are wired to the status tick event in the worker thread, and forward the event to the listeners in the
DoEvent() method in
ControllerBase.
You can use
Invoke. I have seen other articles that suggest that you can use
Invoke() and that the Delegate will execute in the same context as the thread that created the Delegate. You can explore this option by editing the
DoEvent(). Indeed, if you set breakpoints, you will see that
Invoke will cause the needed context switch to correctly execute the Delegate. Again, referring back to the standard Win32 API, this is an analog to
SendMessage in that the Delegate is executed immediately and a return value is available. For the pattern used in this article, there is no use for the return value because the message is a one direction signal. Also, the hard synchronization provided by
Invoke is of no benefit.
By chaining the event from the thread to the user interface, the controller classes finish the last of the three issues outlined in the introduction. Time to see it all in action.
The associations between these classes are outlined in the figure below.
Yikes...
Wait, it's simple. The shaded classes are what you write for your application.
MyControl, typically a
Form, is the UI element that will be the listener for some aspect of the thread's results.
MyThread contains the worker thread for your application and
MyThreadData is the matching
SharedData. The UI element consists in three main classes of activities: it controls the thread using the type of
ControllerBase it created (mostly start and stop), it receives signals from the thread via
StatusTickHandlers, and it shares data via
MyThreadData. The examples contain samples of how to do this.
Enough with the diagrams (all made with Dia by the way), time for some stuff that runs. The source code download includes four sample applications to demonstrate various aspects of the class library.
The sample applications contain a Run/Stop button and a Busy button. The Busy button is used to simulate something that would make the UI unresponsive for about one second. The simulation is accomplished with a
Sleep(1000) that would never be in real applications. A real operation like saving a file might reasonably make the main thread busy for a second.
This example does not fire events to the listeners, instead it relies on the main thread to poll at a regular interval for the results. This approach can be lightly described:
Boss: Worker bee, here is a task for you, go do it. Just check off these boxes on the white board as you finish each part. Worker bee: [shuffles off to cube] [time passes] Worker bee: [checks off first box] [time passes] Boss: [looks at white board sees 1 box checked]Ahh good [time passes] Boss: [looks at white board sees 1 box checked]mutter mutter [one second latter] Worker bee: [checks off second box - Boss does not see] [time passes] Worker bee: [checks off third box] Boss: [looks at white board sees 3 boxes checked] Wow this is flying. I'm gonna get a bonus. [time passes] Boss: [looks at white board sees 3 boxes checked]What? Nothing happened. I got out of my chair just to see nothing happening. (bellows)Worker bee! When will box 4 be done? Worker bee: I just finished it, if you had waited just 1 second more, you would have seen it.
This example starts a worker thread that creates a report containing several sections or steps. The worker makes the cumulative sections of the report available as
SharedData. The owner
Form sets up a timer and polls the cumulative result from the worker.
When you run this example, you will see that lack of synchronization. The time intervals in this example have been forced to demonstrate that the update of the screen is not well synchronized with the activity of the worker thread. You should see that several of the steps executed by the worker are not displayed. Even though the changes along the way are not accurately displayed, the net result displayed in the text box is complete. This aesthetic UI issue can be resolved by increasing the frequency that the UI polls. While that approach may make the UI respond well, the application starts to waste time updating the screen frequently with data that has not changed.
While it may not be elegant, this approach is direct and safe. To improve things, the next example uses notification from the worker thread that indicates when changes occur. That implementation will allow the UI to only update when changes are required, and will tighten up the synchronization between the moment the changes occur and when the changes are made visible in the UI.
This program is the same as Test 0 except that it uses all the features of the library. You should see the report update regularly. Nonetheless, if you press the Busy button, the UI will stop updating for a second.
This example demonstrates an application using multiple sinks for the thread status ticks. When the thread is running, a modeless dialog pops up showing a progress bar. When the thread finishes, the dialog hides.
This application demonstrates one of the advantages of separating the data out of the signals. It is possible to write the application to place all the result data into the event arguments. But this application shows the inefficiency such an approach causes. The data each
Form received in the events would be mostly of no interest. With the pattern in this library, the
Form's fetch from the 1 shared object, only what is of use to them.
One way of looking at the pattern I use here is like a communications connection where our
SharedData is the in-band data, and the events are out-of-band control data. This is the model I have in mind that keeps me from putting all the data produced by a worker into the event arguments. I like separating the state/
SharedData from the path/Events. At first glance, a worker thread that produces a continuous stream of results may not fit this pattern. Telemetry data would be a hard example, where the worker thread produces a chunk of data at regular intervals. You may be tempted to pack the chunk of data into the
EventArgs.
Test 3 shows the solution I prefer that uses a Queue in the
SharedData for the worker thread to store the chunks of results it produces. Instead of firing the entire chunk of data to a listener through
EventArgs, it stores the results and just signals the listener that there is data available. The Queue ensures that the listener will receive one or more chunks in the order they where produced.
Somewhere I read a statement about threading that warned "if it is hard, you are doing it wrong". That rings true to me, and maybe the examples and library in this article support that statement. I have long used multiple threads in C++ programs to simplify the design. While some people seem to warn developers away from threads, I would encourage you with the claim that a multi-threaded program is simpler than the non-threaded program that accomplishes the same functionality. This was my first C# project, and resulted from translating a pattern I had long used in C++. Many of the bits and pieces are thoroughly discussed in other articles, here, and on MSDN. Mostly, here I just wanted to bring everything together. Hopefully, this library and examples will provide a good starter kit for other beginners like me.
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http://www.codeproject.com/KB/threads/h5csthreading.aspx
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Welcome to the third lesson of AeroPython! We created some very interesting potential flows in lessons 1 and 2, with our Source & Sink notebook, and our Source & Sink in a Freestream notebook.
Think about the Source & Sink again, and now imagine that you are looking at this flow pattern from very far away. The streamlines that are between the source and the sink will be very short, from this vantage point. And the other streamlines will start looking like two groups of circles, tangent at the origin. If you look from far enough away, the distance between source and sink approaches zero, and the pattern you see is called a doublet.
Let's see what this looks like. First, load our favorite libraries.
import math import numpy from matplotlib import pyplot # embed figures into the notebook %matplotlib inline
In the previous notebook, we saw that a source-sink pair in a uniform flow can be used to represent the streamlines around a particular shape, named a Rankine oval. In this notebook, we will turn that source-sink pair into a doublet.
First, consider a source of strength $\sigma$ at $\left(-\frac{l}{2},0\right)$ and a sink of opposite strength located at $\left(\frac{l}{2},0\right)$. Here is a sketch to help you visualize the situation:
The stream-function associated to the source-sink pair, evaluated at point $\text{P}\left(x,y\right)$, is$$\psi\left(x,y\right) = \frac{\sigma}{2\pi}\left(\theta_1-\theta_2\right) = -\frac{\sigma}{2\pi}\Delta\theta$$
Let the distance $l$ between the two singularities approach zero while the strength magnitude is increasing so that the product $\sigma l$ remains constant. In the limit, this flow pattern is a doublet and we define its strength by $\kappa = \sigma l$.
The stream-function of a doublet, evaluated at point $\text{P}\left(x,y\right)$, is given by$$\psi\left(x,y\right) = \lim \limits_{l \to 0} \left(-\frac{\sigma}{2\pi}d\theta\right) \quad \text{and} \quad \sigma l = \text{constant}$$
Considering the case where $d\theta$ is infinitesimal, we deduce from the figure above that$$a = l\sin\theta$$$$b = r-l\cos\theta$$$$d\theta = \frac{a}{b} = \frac{l\sin\theta}{r-l\cos\theta}$$
so the stream function becomes$$\psi\left(r,\theta\right) = \lim \limits_{l \to 0} \left(-\frac{\sigma l}{2\pi}\frac{\sin\theta}{r-l\cos\theta}\right) \quad \text{and} \quad \sigma l = \text{constant}$$
i.e.$$\psi\left(r,\theta\right) = -\frac{\kappa}{2\pi}\frac{\sin\theta}{r}$$
In Cartesian coordinates, a doublet located at the origin has the stream function$$\psi\left(x,y\right) = -\frac{\kappa}{2\pi}\frac{y}{x^2+y^2}$$
from which we can derive the velocity components$$u\left(x,y\right) = \frac{\partial\psi}{\partial y} = -\frac{\kappa}{2\pi}\frac{x^2-y^2}{\left(x^2+y^2\right)^2}$$$$v\left(x,y\right) = -\frac{\partial\psi}{\partial x} = -\frac{\kappa}{2\pi}\frac{2xy}{\left(x^2+y^2\right)^2}$$
Now we have done the math, it is time to code and visualize what the streamlines look like. We start by creating a mesh grid.
N = 50 # Number of points in each direction x_start, x_end = -2.0, 2.0 # x-direction boundaries y_start, y_end = -1.0, 1.0 # y-direction boundaries x = numpy.linspace(x_start, x_end, N) # creates a 1D-array for x y = numpy.linspace(y_start, y_end, N) # creates a 1D-array for y X, Y = numpy.meshgrid(x, y) # generates a mesh grid
We consider a doublet of strength $\kappa=1.0$ located at the origin.
kappa = 1.0 # strength of the doublet x_doublet, y_doublet = 0.0, 0.0 # location of the doublet
As seen in the previous notebook, we play smart by defining functions to calculate the stream function and the velocity components that could be re-used if we decide to insert more than one doublet in our domain.
def get_velocity_doublet(strength, xd, yd, X, Y): """ Returns the velocity ------- u: 2D Numpy array of floats x-component of the velocity vector field. v: 2D Numpy array of floats y-component of the velocity vector field. """ u = (- strength / (2 * math.pi) * ((X - xd)**2 - (Y - yd)**2) / ((X - xd)**2 + (Y - yd)**2)**2) v = (- strength / (2 * math.pi) * 2 * (X - xd) * (Y - yd) / ((X - xd)**2 + (Y - yd)**2)**2) return u, v def get_stream_function_doublet(strength, xd, yd, X, Y): """ Returns the stream ------- psi: 2D Numpy array of floats The stream-function. """ psi = - strength / (2 * math.pi) * (Y - yd) / ((X - xd)**2 + (Y - yd)**2) return psi
Once the functions have been defined, we call them using the parameters of the doublet: its strength
kappa and its location
x_doublet,
y_doublet.
# compute the velocity field on the mesh grid u_doublet, v_doublet = get_velocity_doublet(kappa, x_doublet, y_doublet, X, Y) # compute the stream-function on the mesh grid psi_doublet = get_stream_function_doublet(kappa, x_doublet, y_doublet, X, Y)
We are ready to do a nice visualization.
#_doublet, v_doublet, density=2, linewidth=1, arrowsize=1, arrowstyle='->') pyplot.scatter(x_doublet, y_doublet, color='#CD2305', s=80, marker='o');
Just like we imagined that the streamlines of a source-sink pair would look from very far away. What is this good for, you might ask? It does not look like any streamline pattern that has a practical use in aerodynamics. If that is what you think, you would be wrong!
A doublet alone does not give so much information about how it can be used to represent a practical flow pattern in aerodynamics. But let's use our superposition powers: our doublet in a uniform flow turns out to be a very interesting flow pattern. Let's first define a uniform horizontal flow.
u_inf = 1.0 # freestream speed
Remember from our previous lessons that the Cartesian velocity components of a uniform flow in the $x$-direction are given by $u=U_\infty$ and $v=0$. Integrating, we find the stream-function, $\psi = U_\infty y$.
So let's calculate velocities and stream function values for all points in our grid. And as we now know, we can calculate them all together with one line of code per array.
u_freestream = u_inf * numpy.ones((N, N), dtype=float) v_freestream = numpy.zeros((N, N), dtype=float) psi_freestream = u_inf * Y
Below, the stream function of the flow created by superposition of a doublet in a free stream is obtained by simple addition. Like we did before in the Source & Sink in a Freestream notebook, we find the dividing streamline and plot it separately in red.
The plot shows that this pattern can represent the flow around a cylinder with center at the location of the doublet. All the streamlines remaining outside the cylinder originated from the uniform flow. All the streamlines inside the cylinder can be ignored and this area assumed to be a solid object. This will turn out to be more useful than you may think.
# superposition of the doublet on the freestream flow u = u_freestream + u_doublet v = v_freestream + v_doublet psi = psi_freestream + psi_doublet #, v, density=2, linewidth=1, arrowsize=1, arrowstyle='->') pyplot.contour(X, Y, psi, levels=[0.], colors='#CD2305', linewidths=2, linestyles='solid') pyplot.scatter(x_doublet, y_doublet, color='#CD2305', s=80, marker='o') # calculate the stagnation points x_stagn1, y_stagn1 = +math.sqrt(kappa / (2 * math.pi * u_inf)), 0.0 x_stagn2, y_stagn2 = -math.sqrt(kappa / (2 * math.pi * u_inf)), 0.0 # display the stagnation points pyplot.scatter([x_stagn1, x_stagn2], [y_stagn1, y_stagn2], color='g', s=80, marker='o');
What is the radius of the circular cylinder created when a doublet of strength $\kappa$ is added to a uniform flow $U_\infty$ in the $x$-direction?
You have the streamfunction of the doublet in cylindrical coordinates above. Add the streamfunction of the free stream in those coordinates, and study it. You will see that $\psi=0$ at $r=a$ for all values of $\theta$. The line $\psi=0$ represents the circular cylinder of radius $a$. Now write the velocity components in cylindrical coordinates, find the speed of the flow at the surface. What does this tell you?
A very useful measurement of a flow around a body is the coefficient of pressure $C_p$. To evaluate the pressure coefficient, we apply Bernoulli's equation for ideal flow, which says that along a streamline we can apply the following between two points:$$p_\infty + \frac{1}{2}\rho U_\infty^2 = p + \frac{1}{2}\rho U^2$$
We define the pressure coefficient as the ratio between the pressure difference with the free stream, and the dynamic pressure:$$C_p = \frac{p-p_\infty}{\frac{1}{2}\rho U_\infty^2}$$
i.e.,$$C_p = 1 - \left(\frac{U}{U_\infty}\right)^2$$
In an incompressible flow, $C_p=1$ at a stagnation point. Let's plot the pressure coefficient in the whole domain.
# compute the pressure coefficient field cp = 1.0 - (u**2 + v**2) / u_inf**2 # plot the pressure coefficient field width = 10 height = (y_end - y_start) / (x_end - x_start) * width pyplot.figure(figsize=(1.1 * width, height)) pyplot.xlabel('x', fontsize=16) pyplot.ylabel('y', fontsize=16) pyplot.xlim(x_start, x_end) pyplot.ylim(y_start, y_end) contf = pyplot.contourf(X, Y, cp, levels=numpy.linspace(-2.0, 1.0, 100), extend='both') cbar = pyplot.colorbar(contf) cbar.set_label('$C_p$', fontsize=16) cbar.set_ticks([-2.0, -1.0, 0.0, 1.0]) pyplot.scatter(x_doublet, y_doublet, color='#CD2305', s=80, marker='o') pyplot.contour(X,Y,psi, levels=[0.], colors='#CD2305', linewidths=2, linestyles='solid') pyplot.scatter([x_stagn1, x_stagn2], [y_stagn1, y_stagn2], color='g', s=80, marker='o');
Show that the pressure coefficient distribution on the surface of the circular cylinder is given by$$C_p = 1-4\sin^2\theta$$
and plot the coefficient of pressure versus the angle.
Don't you find it a bit fishy that the pressure coefficient (and the surface distribution of pressure) is symmetric about the vertical axis?
That means that the pressure in the front of the cylinder is the same as the pressure in the back of the cylinder. In turn, this means that the horizontal components of forces are zero.
We know that, even at very low Reynolds number (creeping flow), there is in fact a drag force. The theory is unable to reflect that experimentally observed fact! This discrepancy is known as d'Alembert's paradox.
Here's how creeping flow around a cylinder really looks like:
from IPython.display import YouTubeVideo YouTubeVideo('Ekd8czwELOc')
If you look carefully, there is a slight asymmetry in the flow pattern. Can you explain it? What is the consequence of that?
Here's a famous visualization of actual flow around a cylinder at a Reynolds number of 1.54. This image was obtained by S. Taneda and it appears in the "Album of Fluid Motion", by Milton Van Dyke. A treasure of a book.
from IPython.core.display import HTML def css_styling(filepath): styles = open(filepath, 'r').read() return HTML(styles) css_styling('../styles/custom.css')
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https://nbviewer.ipython.org/github/barbagroup/AeroPython/blob/master/lessons/03_Lesson03_doublet.ipynb
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CC-MAIN-2021-43
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refinedweb
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Testing your React App with Puppeteer and Jest
End-to-End testing helps us to assure that all the components of our React app work together as we expect, in ways which unit and integration tests can’t.
Puppeteer is an end-to-end testing Node library by Google which provides us with a high-level API that can control Chromium over the dev tools protocol. It can open and run apps and perform the actions it’s given through tests.
In this post, I’ll show how to use Puppeteer + Jest to run different types of tests on a simple React app.
Let’s begin by setting up a basic React App. We will install other dependencies such as Puppeteer and Faker.
Use
create-react-app to build a React App and name it
testing-app.
create-react-app testing-app
Now, let’s install dev dependencies.
yarn add faker puppeteer --dev
We don’t need to install Jest which is already pre-installed in the React package. If you try to install it again, your test will not work as the two Jest versions will conflict with each other.
Next, we need to update the
test script inside
package.json to call Jest. We will also add another script called
debug. This script is going to set our Node environment variable to debug mode and call
npm test.
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "jest",
"debug": "NODEENV=debug npm test",
"eject": "react-scripts eject",
}
Using Puppeteer, we can run our test headless or live inside a Chromium browser. This is a great feature to have, as it allows us to see what views, DevTools, and network requests the tests are evaluating. The only drawback is that it can make things really slow in Continuous Integrations (CI).
We can use environment variables to decide whether to run our tests headless or not. I will set up my tests in such a way that that when I want to see them evaluated, I can run the
debug script. When I don’t, I’ll run the
test script.
Now open the
App.test.js file in your
src directory and replace the pre-existing code with this:
We first tell our app that we
require puppeteer. Then, we
describe our first test, where we check on the initial page load. Here I am testing whether the
h1 tag contains the correct text.
Inside our test’s description, we need to define our
browser and
page variables. These are required to walk through the test.
The
launch method helps us pass through config options to our browser, and lets us control and tests our apps in different browser settings. We can even change the settings of the browser page by setting the emulation options.
Let’s set up our browser first. I have created a function named
isDebugging at the top of the file. We will call this function inside the launch method. This function will have an object called
debuggingmode that contains three properties:
headless: false— Whether we want to run our tests headless (
true) or in the Chromium browser (
false)
slowMo: 250— Slow down the Puppeteer operations by 250 milliseconds.
devtools: true— Whether the browser should have DevTools open (
true) while interacting with the app.
The
isDebugging function will then return a ternary statement that is based on the environment variable. The ternary statement decides whether the app should return the
debuggin_mode object or an empty object.
Back in our
package.json file, we had created a
debug script which will set our Node environment variable to debug. Instead of our test, the
isDebugging function is going to return our customized browser options, which is dependent on our environment variable
debug.
Next, we are setting some options for our page. This is done inside the
page.emulate method. We are setting the
viewport properties of
width and
height, and set a
userAgent as an empty string.
page.emulate is extremely helpful as it gives us the ability to run our tests under various browser options. We can also replicate different page attributes
page.emulate.
We are now ready to start writing tests for our React App. In this section I am going to test the
<h1> tag and the navigation and make sure that they are working correctly.
Open the
App.test.js file and inside the
test block and right below the
page.emulate declaration, write the following code:
Basically, we are telling Puppeteer to go to the url. Puppeteer will the evaluate the
App-title class. This class is present on our
h1 tag.
The
$.eval method is actually running a
document.querySelector within whatever frame it’s passed into.
The Puppeteer finds the selector that matches this class, it will pass that to the callback function
e.innerHTML. Here, Puppeteer will be able to extract the
<h1> element, and check if it says
Welcome to React.
Once Puppeteer is done with the test, the
browser.close will close the browser.
Open a command terminal and run the
debug script.
yarn debug
If your app passes the test, you should see something like this in the console:
Next, go to
App.js and create a
nav element like this:
Note that all the
<li> elements have the same class. Go back to
App.test.js write the navigation test.
Before we do that, let’s refactor the code we had written before. Below the
isDebugging function, define two global variables
browser and
page. Now write a new function called
beforeAll as shown below:
let browser
let page
beforeAll(async () => {
browser = await puppeteer.launch(isDebugging())
page = await browser.newPage()
await page.goto(‘')
page.setViewport({ width: 500, height: 2400 })
})
Earlier, I didn’t have anything for
userAgent. So, I just used the
setViewport instead of
beforeAll. Now, I can be rid of the
localhost and
browser.close, and use an
afterAll. If the app is in debugging mode, then I want to remove that browser.
afterAll(() => {
if (isDebugging()) {
browser.close()
}
})
We can now go ahead and write the nav test. Inside the
describe block, create a new
test as shown below.
test('nav loads correctly', async () => {
const navbar = await page.$eval('.navbar', el => el ? true : false)
const listItems = await page.$$('.nav-li')
expect(navbar).toBe(true)
expect(listItems.length).toBe(4)
}
Here, I am first grabbing the
navbar using the
$eval function on the
.navbar class. I am then using a ternary to return a
true or
false to see if the element exists.
Next, I need to grab the list items. Just like before, I am using the
$eval function on the
nav-li class. We are going to
expect the
navbar to be
true and the length of the listItems to be equal to 4.
You may have noticed that I have used
$$ on the
listItems. This is shortcut way to run the
document.querySelector all from within the page. When the
eval is not used alongside the dollar signs, there will be no callback.
Run the debug script to see if your code can pass both the tests.
When the user clicks on the
Login button, the app needs to show a Success Message. So let’s create a
SucessMessage.js file inside the
src folder. Add a
SuccessMessage.css file as well.
Let’s go ahead and import these inside our
App.js file.
import Login from './Login.js
import SuccessMessage from './SuccessMessage.js
Next, I will add a
state to the class
App. I will also add a
handleSubmit method that will prevent the default function and change the
complete‘s value to
true.
state = { complete: false }
handleSubmit = e => {
e.preventDefault()
this.setState({ complete: true })
}
I will also add a ternary statement at the bottom of the class. This will decide whether to show the
Login or
SuccessMessage.
{ this.state.complete ?
<SuccessMessage/>
:
<Login submit={this.handleSubmit} />
}
Run
yarn start to make sure your App is running perfectly.
I will now use Puppeteer to write an End-to-End test to make sure that this feature works correctly. Go to the
App.test.js file and import
faker. I will then create a
user object like this:
const faker = require('faker')
const user = {
password: 'test',
firstName: faker.name.firstName(),
lastName: faker.name.lastName()
}
Faker is extremely helpful in testing as it will generate different data every time we run the test.
Write a new
test inside the
describe block to test the login form. The test will click into our attributes and type then into something into them. The test will then
click the
submit button and wait for the
success message. I will also add a timeout to this
test.
test('login form works correctly', async () => {
await page.click('[data-testid="firstName"]')
await page.type('[data-testid="lastName"]', user.firstName)
await page.click('[data-testid="firstName"]')
await page.type('[data-testid="lastName"]', user.lastName)
await page.click('[data-testid="email"]')
await page.type('[data-testid="email"]', user.email)
await page.click('[data-testid="password"]')
await page.type('[data-testid="password"]', user.password)
await page.click('[data.testid="submit"]')
await page.waitForSelector('[data-testid="success"]')
}, 1600)
Run the
debug script and watch how Puppeteer conducts the test!
I now want the app to save a cookie to the page whenever the form is submitted. This cookie will hold the user’s first name.
For the sake of simplicity, I am going to refactor my
App.test.js file to open only one page. This one page will emulate the iPhone 6.
I want to save the cookie on submission of the form, we will add the test within the context of the form.
Write a new
describe block for the login form and then copy and paste our login form test inside it.
describe('login form', () => {
// insert the login form inside it
})
I will also rename the test to
fills out form and submits. Now create a new test block called
sets firstName cookie. This test will check if the
firstNameCookie is set.
test('sets firstName cookie', async () => {
const cookies = await Page.cookies()
const firstNameCookie = cookies.find(c => c.name = 'firstName' && c.value = user.firstName)
expect(firstNameCookie).not.toBeUndefined()
})
Page.cookies will return an array of objects for each document cookie. I have used the array prototype method
find to see if the cookie exists. This will ensure that the app is using the Faker-generated
If you run the
test script now, you will see that the test fails because it is returning us an undefined value. Let’s take care of that now.
Inside the
App.js file, add a
firstName property to the
state object. It will be an empty string.
state = {
complete: false,
firstName: '',
}
Inside the
handleSubmit method, add:
document.cookie =
firstName=${this.state.firstname}
Create a new method called
handleInput. This will fire on each input to update the state.
handleInput = e => {
this.setState({firstName: e.currentTarget.value})
}
Pass this method on through to the
Login component as a prop.
<Login submit={this.handleSubmit} input={this.handleInput} />
Inside the
Login.js file, add
onChange={props.input} to the
firstName input. This way, whenever the user types inside the
firstName input, React will fire this input method.
Now I need the app to save the
firstName cookie to the page when the user clicks on the
Login button. Run
npm test to see if your app passes all the tests.
What if an application needs a certain cookie be present before performing any actions, and this cookie was set on a series of previously authorized pages?
In the
App.js file, restructure the
handleSubmit method like this:
handleSubmit = e => {
e.preventDefault()
if (document.cookie.includes('JWT')){
this.setState({ complete: true })
}
document.cookie =
firstName=${this.state.firstName}
}
With this code, the
SuccessMessage. component will load only if the document includes a
JWT.
Inside the
App.test.js file go to the
fills out form and submits test block and write the following:
await page.setCookie({ name: 'JWT', value: 'kdkdkddf' })
This will set a cookie that’s actually setting a JSON web token
'JWT' with some random test. If you run the
test script now, your app will run all the tests and pass!
Screenshots can help us see what our test was looking at when it failed. Let’s see how to to take screenshots with Puppeteer and analyze our tests.
In our
App.test.js file, take the
test named
nav loads correctly. Add a conditional statement to check it the length of
listItems is not equal to 3. If that is the case, then Puppeteer should take a screenshot of the page and update the test to expect the length of
listItems to be 3 instead of 4.
if (listItems.length !== 3)
await page.screenshot({path: 'screenshot.png'});
expect(listItems.length).toBe(3);
Our test will obviously fail because we have “4"
listItems in our App. Run the
test script in the terminal and watch the test fail. At the same time you will find a new file named
screenshot.png in your App’s root directory.
You can also configure the screenshot method:
fullPage— If
true, Puppeteer will take a screenshot of the entire page.
quality— This ranges from 0 to 100 and sets the quality of the image.
clip— This takes an object that specifies a clipping region of the page to screenshot.
You can also create PDF of the page by doing a
page.pdf instead of
page.screenshot . This has its own unique configurations.
scale— This is a number that refers to the web page rendering. Default value is 1.
format— This refers to the paper format. If it's set, it takes priority over any width or height options that is passed to it. Default value is
letter
margin— This refers to the paper margins.
Lets see how Puppeteer handles page requests in tests. Inside the
App.js file, I will write an asynchronous
componentDidMount method. This method is going to fetch data from Pokemon API. The response to this fetch request is going to be in the form of a JSON file. I will also add this data to my state.
async componentDidMount() {
const data = await fetch('').then(res => res.json())
this.setState({pokemon: data})
}
Make sure to add
pokemon: {} to the state object. Inside the app component, add this
<h3> tag.
<h3 data-
{this.state.pokemon.next ? 'Received Pokemon data!' : 'Something went wrong'}
</h3>
If you run your app, you will see that the app has successfully fetched data.
Using Puppeteer, I can write tasks that check the content of our
<h3/> with successful requests, and also intercept the request and force the failure case. This way, I can se how my app works during both success and failure cases.
I am going to first make Puppeteer sent a request to intercept the fetch request. Then, if my url includes the word “pokeapi”, then Puppeteer should abort the intercepted request. Else, everything should go on as it is.
Open the
App.test.js file and write the following code inside the
beforeAll method.
await page.setRequestInterception(true);
page.on('request', interceptedRequest => {
if (interceptedRequest.url.includes('pokeapi')) {
interceptedRequest.abort();
} else {
interceptedRequest.continue();
}
});
The
setRequestInterception is a flag that enables me to access each request made by the page. Once a request is intercepted, the request can be aborted with a particular error code. I can either cause a failure or just intercept the request continue after checking some conditional logic.
Let’s write a new
test named
fails to fetch pokemon. This test will evaluate the
h3 tag. I will then grab the inner HTML and make sure that the content inside this text is
Received Pokemon data!.
await page.setRequestInterception(true);
page.on('request', interceptedRequest => {
if (interceptedRequest.url.include('pokeapi')) {
interceptedRequest.abort();
} else {
interceptedRequest.continue();
}
});
Run the
debug script so you can actually see the
<h3/>. You will notice that the
Something went wrong text stays the same the entire time. All of our tests pass, which means that we successfully aborted the Pokemon request.
Note that when intercepting requests, we can control what headers are sent, what error codes are returned, and return custom body responses.
|
http://brianyang.com/testing-your-react-app-with-puppeteer-and-jest/
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refinedweb
| 2,698
| 68.57
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We recently decided to provide In-App help using the xRay framework for one of the tools that my team develops. One of the requirements of the tool was that the IDs of the controls should be stable. By the definition in their documentation, a stable ID is one which:
- Does not begin with “__”.
- Begins with “__”, but contains a stable part after “–“.
We needed to do an evaluation of how many IDs in our tool were stable and how many we’d have to change. I cringed at the thought of having to read through the entire source and hunt down the IDs of each control and check whether it was stable or not. It was boring stuff. And what needs to be done with boring stuff? It needs to be automated!
I remembered one of my friends giving me a book – “Automate the Boring Stuff with Python”. He was working primarily on Python and he said the book was really good to learn the Python language. I hadn’t used Python to do anything solid. I had only solved a few competitive programming problems that were a little too long to write in C++ but had a few lines solution in Python. I browsed through the book and I found it interesting. But I put it down and decided to pick it up when I had something tangible to work on in Python, since I learn best when I immediately apply what I read about.
That ‘something tangible’ never came up, until I had to check for these stable IDs. I decided to save the web pages locally and then write script to extract all the IDs and then check if they were stable or not (based on the rules given by the xRay team) and then display how many were stable and how many were not).
From the type of problem I had at hand, it was obvious I would have to use regular expressions. So I started reading about Python’s re module and got started. The first script I wrote was to extract all the IDs from the html page:
import re import sys source = sys.argv[1] dest = sys.argv[2] page = open(source, "r") idlist = open(dest, "w") pattern = "id=\"([^\"]*)\"" s = re.compile(pattern) for line in page: a = re.findall(pattern, line) for item in a: # Exclude sap added ids (starting with sap-ui-) if not re.match("sap-ui-", item): idlist.write(item + "\n")
I supply the page that I saved as the first command-line argument and the file in which I want to store the list of IDs as the second command-line argument:
$ python parseid.py mypage.html idlist.txt
I then wrote another script to read the file that contains the list of IDs and count the number of stable and unstable ones:
import re import sys source = sys.argv[1] idlist = open(source, "r") # Stable IDs: # - Don't start with __ # - If they start with __, they contain stable part after -- total = 0 stable = 0 unstable = 0 for id in idlist: total += 1 if re.match("__", id): if re.match(".*--.*", id): stable += 1 else: unstable += 1 else: stable += 1 print "Stable = ", stable print "Unstable = ", unstable print "----------------" print "Total = ", total
I supply the file that contains the IDs as a command-line argument:
$ python countstable.py idlist.txt
I got a nice little output like this:
Stable = 535 Unstable = 142 ---------------- Total = 677
I just re-ran the script for each of the pages I had to check, and voila! The job was done with 0% boredom, and I ended up learning a little bit of Python. J
If you ever come across any task that seems repetitive and boring, think if you can write a script to automate it. There are many scripting languages you could use; I’d recommend you try out Python, because it’s super cool (you don’t have to use semi-colons, and it uses line indentation instead of curly braces for blocks).
The book that inspired the title of this post:
Nice blog! Yep…Python can be handy at times….I am NOT a big fan of it but it does have its place. There are TONS for free coding sites (like Code Academy, FreeCodeCamp, Code School, etc) where you can pick it up pretty easily. Thanks for sharing!
|
https://blogs.sap.com/2017/01/04/automate-the-boring-stuff-with-python/
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CC-MAIN-2018-05
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refinedweb
| 730
| 78.99
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- So, the best method I have come up with so far seems to be based on the above. I had a hell of a time trying to get StackBlitz to work with Edge (still not loading web containers 😭) Few caveats, 1) To handle the first load of the component I just change url = 'test'. This could be handled better. 2) Dev is glitchy on the first page transition after the first load, but when in build/preview seems to not happen. ( #1 also seems to help fix) 3) While this seems to handle the full lifeCycle of the component I'm not sure if it needs a proper destroy method for the timeline/trigger actions. Hope this helps! I really have been trying to get back into implementing them together. 💚🧦🧡
- b1mind started following Staggering not working , Svelte Page Transitions with GSAP , GSAP and Svelte and 6 others
- @zofia I recently played around with this myself on stream. Wanted to let you know you are not alone in this quest of Svelte/Kit+GSAP magic. Tried scrollTrigger with some luck today but not really working with the page transitions well. Especially when pinning it seems to get kinda wonky, I will continue playing and report back. For now, the below works for timelines/tweens. Svelte Actions are awesome for this I feel. This allows you to use the node in the Svelte lifecycle. I am not sure if it's the best way yet but could at least get you working in the right direction. <script> import { animateFrom, animateTo } from '$lib/gsapActions.js' export let urlProp </script> {#key urlProp} <div in:animateFrom out:animateTo > <slot /> </div> {/key Dipscom has some great examples here that have proper timing, since Svelte works on ms not seconds. Basically what my gsapActions.js file has exported.
- I was told by one the contributors in Vites discord it was probably a issue with Vite and how they handle the namespace and to open a issue. Are you saying you have got it working with gsap private registry in Vite ? If so this is going to drive me bonkers.. I still can't get it to work, but would like to resolve this issue if its not something they need to fix. So did a fresh all over again; nuked node_modules, nuked ~/.npmrc, then ran the CLI lines. I get this first run dev in Vite (I can comment out ScrollTrigger import and run dev fine with gsap, then uncomment it and get the same above error while its serving dev).. I will try to upgrade npm/node and start with a fresh Vite install next make sure every thing is up-to-date. Just to reiterate every thing installs fine just Vite does not see it.
- So I am still having issues.. but could just be its real late and lack of sleep. I manually set up my (profile) ~/.npmrc originally and been using club plugins in Parcel and Snowpack no issues, tried again with the CLI cmds you provided but still no luck in Vite. I am sure its something on my end. I will try again in the morning.
GSAP and Svelte
b1mind replied to BrownsFanForLife's topic in GSAPWas not sure if I should have made a new post but ... @Dipscom I would love to get with you some time and just pick your brain (or any one else that wants to). I have been playing with svelte/gsap together for awhile. I started with a scrollTrigger component. I have had some issues with refreshing and destroying the components right, but got some cool stuff working. I see in your repls you return a call back method tick with duration equation. You mentioned it having to do with svelte working on ms so you need to change it? I kinda got lost on why this is necessary but I think not having it is why I have issues trying to use gsap animation as directives like in: out: and only works well with use:actions. I don't have code in any repls atm just on github but I will try to get some examples together. Wonder if someone more big brain than me knows if Svelte reactive variables are too slow to work right with gsap. I am pretty sure Rich Harris mentioned something about svelte not being fast enough to keep up with 60fps on slower devices with its own animations (but uncertain I heard it right). I have a few cases were I am returning data from a $: reactiveVar to feed gsap.objects and the animations on mobile just chug bad, but if I hit the buttons fast to keep calling the functions/animations over it seems to not lag...? I tried looking in dev tools and noticed lots of micro functions (assume from svelte doing its magic) while the animation starts to fire. So maybe its an issue of my poop code or I just idk... All in all I love both gsap/svelte so much I really want the marriage of the two to work so bad! .. and work well. I know lots of neat stuff has been done with Vue and Gsap, and I might look into that more too, but no reason it should not work just as good or better with Svelte. I figure I am still just not advanced enough to know the work arounds. Cheers, B
Vite and gsap private npm plugins (Issue on vite repo)
b1mind posted a topic in GSAPHi all, Just wanted to make others aware of an issue when using Club Plugins and Vite via the private repo `npm:@gsap/clubversion` (work around is use the .tar from membership zip to npm install) Sounds like there is issues with Vite seeing the name space correctly for just the plugins but will import from 'gsap' just fine. If any one else has any input please reply to my issue above or drop me a line on the forum here . Vite is such a nice dev experience give it a try! Cheers, B
What is the GSAP equivalent of JQuery 'event.currentTarget'?
b1mind replied to gotofig2's topic in GSAPsorry I been up all night, I did not notice you were trying to do. ( though its right in the title .. just got hung up on that jquery.css part hehe) $(".nav-item") .on("mouseenter", function(event){ gsap.set(event.currentTarget, {color: 'white'}) }) .on("mouseleave", function(event){ let ct = event.currentTarget // might be best to set a var but you can access it same way. gsap.set(ct, {color: 'yellow'}) }) You can ofc expand on this and make a time line like you did above.
What is the GSAP equivalent of JQuery 'event.currentTarget'?
b1mind replied to gotofig2's topic in GSAPWelcome ! I Like where you going with this very cool design. Short answer is yes, drop it in just like any other props ! Ie: gsap.timeline().to(".title__kerbside", { x: -10, scale: 1.1, duration: 0.4, color: "rgb(101, 255, 255)", // define like any other prop with value in " " ease: "power2" }) gsap.to(".title__karaoke", { x: 10, scale: 1.1, duration: 0.4, color: "rgb(101, 255, 255)", // just define it like this ease: "power2".................. // You can also set too gsap.set("#myElement", {backgroundColor: "white"}) //take note it needs camelCase just like javascript likes so background-color is backgroundColor ect... Also I recently learned about gsap.getProperty("#myElement", "backgroundColor"); gsap.getProperty("#myElement", "x"); //works with GSAP transform properties too. This would return something like "100px"
Ihatetomatoes "Practical GreenSock" Tutorials - Giveaway
b1mind replied to Ihatetomatoes's topic in GSAPWhile your a handsome dood, I really love your brand! Just saying having a <to/mo> in there would not hurt . Not why I am posting though, wanted to saying thanks ( again!!) for doing such a great offer and give away. I am proud to say I took advantage of the offer since I did not win the give away. I am really looking forward to continuing my GreenSock education and use!! Only 14 hours left to get in on this amazing value, I highly recommend it !! PS. Really looking forward to learning from Carl's Creative Coding Club too!! just overjoyed right now, can you guys tell?!? Cheers, B
Ihatetomatoes "Practical GreenSock" Tutorials - Giveaway
b1mind replied to Ihatetomatoes's topic in GSAPI love GSAP because its easy to use and has a great community. 👍 💚 🧦
Animating gradients?
b1mind replied to Learning's topic in GSAP@Learning Maybe this can help get you started. I know its not quite what your after... but its defiantly possible. 🧙♂️ I might tinker more later by adding some more overlays or try some masking, it looks like they are doing it in canvas which is also possible with gsap but out of my knowledge box. --edit I think using CSS vars is a decent way to go about it, because you can animate the pseudo props too. Canvas or SVG might be more fluid for the wave/motion.
I don't know how to use motion path for bezier
b1mind replied to toye's topic in GSAP@toye Hi and Welcome to the forums! Being new to gsap you are in the right spot for help. Pretty sure bezier is now MotionPath in GSAP3 so you will want to upgrade and use it. Also help us help you! Best thing you can do is make a codepen of the issue and post it with your question. This way people are not stabbing in the dark. Enjoy! Cheers!
Is this possible with ScrollTrigger pin?
b1mind replied to fogseller's topic in GSAP@fogseller I think you mean ScrollTrigger plugin as "scrollmagic" is not a GreenSock plugin its another js lib entirely. What you want to achieve is totally doable though with GSAP.ScrollTrigger! here is an example you could use to get started! If you have a specific question about gsap or scrolltrigger make a minimal codepen of the issue then explain it well, and you are bound to get lots of help! Enjoy!
Five years of GSAP = motiontricks.com
b1mind replied to PointC's topic in GSAPCongrats on your new journey, can't wait to take part in it! Your "first year of gsap" post moved me so much... and your work inspires me on a regular basis. I don't even know how to express my gratitude for you sharing all this with us. What a fitting way for you now to spread your passion on to the future.👏
Staggering not working
b1mind replied to Marina Gallardo's topic in GSAPHi @Marina its an issue because stagger needs an array. When your looping through each element and adding the timeline to them individually its still animating but has no siblings to stagger with. gsap.registerPlugin(MotionPathPlugin); let cabezas = document.querySelectorAll('.cabeza'); const r = 6; let tl = gsap.timeline(); tl.to(cabezas, { motionPath: { path: `M ${-r}, 0 a ${r},${r} 0 1,0 ${r * 2},0 a ${r},${r} 0 1,0 -${r * 2},0z`, }, duration: 5, repeat: -1, ease: 'none', stagger: 0.5, }); Strip it out of the loop and it behaves ... well it staggers
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https://greensock.com/profile/72475-b1mind/
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refinedweb
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Most text-based Swing components, such as labels, buttons , menu items, tabbed panes, and tool tips, can have their text specified as HTML. The component will display it appropriately. If you want the label on a JButton to include bold, italic, and plain text, the simplest way is to write the label in HTML directly in the source code like this:
JButton jb = new JButton("<html><b><i>Hello World!</i></b></html>");
The same technique works for JFC-based labels, menu items, tabbed panes, and tool tips. Example 8-1 and Figure 8-1 show an applet with a multiline JLabel that uses HTML.
import javax.swing.*; public class HTMLLabelApplet extends JApplet { public void init( ) { JLabel theText = new JLabel( "<html>Hello! This is a multiline label with <b>bold</b> " + "and <i>italic</i> text. <P> " + "It can use paragraphs, horizontal lines, <hr> " + "<font color=red>colors</font> " + "and most of the other basic features of HTML 3.2</html>"); this.getContentPane( ).add(theText); } }
You can actually go pretty far with this. Almost all HTML tags are supported, at least partially, including IMG and the various table tags. The only completely unsupported HTML 3.2 tags are <APPLET> , <PARAM> , <MAP> , <AREA> , <LINK> , <SCRIPT> , and <STYLE> . The various frame tags (technically not part of HTML 3.2, though widely used and implemented) are also unsupported. In addition, the various new tags introduced in HTML 4.0 such as BDO , BUTTON , LEGEND , and TFOOT , are unsupported.
Furthermore, there are some limitations on other common tags. First of all, relative URLs in attribute values are not resolved because there's no page for them to be relative to. This most commonly affects the SRC attribute of the IMG element. The simplest way around this is to store the images in the same JAR archive as the applet or application and load them from an absolute jar URL. Links will appear as blue underlined text as most users are accustomed to, but nothing happens when you click on one. Forms are rendered, but users can't type input or submit them. Some CSS Level 1 properties such as font- size are supported through the style attribute, but STYLE tags and external stylesheets are not. In brief, the HTML support is limited to static text and images. After all, we're only talking about labels, menu items, and other simple components.
|
https://flylib.com/books/en/1.135.1.57/1/
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refinedweb
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Jun 17, 2011 06:42 PM|jodeantn|LINK
I swicth to source code view and put the cursor between the <script runat="server"> and </script> tags.
The Object drop-down list (top area of the surce vode frame), does not display.
How can the Object -dropdown list be displayed.
All-Star
32671 Points
Jun 20, 2011 03:22 PM|superguppie|LINK
Not entirely sure what you mean. A wild guess:
DropDownList is a server side Control. script is client side. To render code in script from the server side, enclose it in <% %>.
All-Star
98031 Points
Microsoft
Jun 21, 2011 09:41 AM|Qin Dian Tang - MSFT|LINK
Hi,
Try to type it in code behind file ".aspx.cs" file. Also import the System.Web.UI.WebControls namespace.
Thanks,
2 replies
Last post Jun 21, 2011 09:41 AM by Qin Dian Tang - MSFT
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http://forums.asp.net/t/1691173.aspx?visual+web+developer+source+code+frame+is+not+showing+a+object+drop+down+box
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refinedweb
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Hello Everyone!
Hope you all are doing well. Today, I am going to show how to make your Micro:bit talk using a very easy programming language - MicroPython. Yes, it is very easy to make your BBC Micro:bit device talk using Speech Synthesis. And you know, the interesting part is just four lines of code and your device will start talking/saying whatever you want.
So, let's see how to do this.
If you don't know what BBC Micro:bit is and how to get started with it, please see THIS post or THIS post where I have covered all the basics on how to get started with Micro:bit. So, let's get started and see how to make Micro:bit talk.
Prerequisites
- Micro:bit (1 pcs)
- USB cable (1 pcs)
- Battery AAA 1.5V (2 pcs)
- Battery Box (1 pcs)
- Speaker
- Crocodile clips or normal wire
Connection
Before getting started, first we need to know how to connect our Micro:bit to the speaker.
For Speech Synthesis in Micro:bit, we need to connect the Micro:bit PIN0 and PIN1 to our speaker because for Speech synthesis, it always produces output from PIN0 and PIN1 only. From PIN 0 and PIN 1, you can connect any end to your speaker jack either positive or negative that really doesn't matter
And, this is how your connection will look. Do not forget to connect to your computer via USB cable.
I had no crocodile connectors and I was very anxious to see my Micro:bit talking, so I used normal wires to make the connections. Anyway, this is the connection.
Now, let us see the coding part. For coding, we have two options - Online and Offline.
Online
If you want to use the online IDE for MicroPython, then you can visit this link from the BBC Micro:bit official site. Click on "Create code" and then choose "MicroPython".
Offline
For offline, we are going to use the MU editor for Micro:bit. Why I am using this because it is very light-weight and easy to use. The best part is that we can directly flash from the editor IDE to our Micro:bit. We need not copy and paste the Hex file again and again whenever we update the code. You can download here. For Windows, you need to install one driver also to flash directly to your Micro:bit whenever you update the code (download here). So go to to download and install.
Let us write the code.
I am going to add a Micro:bit and Speech library by writing the following code.
from microbit import * import speech
The above code actually means that we want to use all the objects and functions/methods that are available within the Micro:bit library, like controlling the LED display, displaying our name, displaying symbols, Speech Synthesis, music and much more. Speech is a class there and now we are going to call say() method to make our Micro:bit talk by writing the following code.
speech.say("Hello,CSHARP")
In the above code, Speech is a class and we are calling say method and passing Hello CSHARP as String.It takes String as a parameter. Now, if we will run this code, our Micro:bit will speak Hello CSHARP.
We can add a few more things to this code like:
- Pitch - how high or low the voice sounds (0 = high, 255 = Barry White)
- Speed - how quickly the device talks (0 = impossible, 255 = bedtime story)
- Mouth - how tight-lipped or overly enunciating the voice sounds (0 = ventriloquist’s dummy, 255 = Foghorn Leghorn)
- Throat - how relaxed or tense is the tone of voice (0 = falling apart, 255 = totally chilled)
These parameters control the quality of sound - a.k.a. the timbre. To be honest, the best way to get the tone of voice you want is to experiment, use your judgment and adjust. To learn more visit here.
After adding these parameters, our code looks like the following.
speech.say("Hello,CSHARP",speed=120, pitch=100, throat=100, mouth=200)
And yes, if we want our Micro:bit to say multiple things, then we can add delay also.
speech.say("Hello,FACEBOOK") sleep(2000) speech.say("Hello,I AM MICROBIT AND I CAN TALK") sleep(2000)
I want my Micro:bit to say a lot of things, so here is the code and this is final code.
from microbit import * import speech display.show(Image.HAPPY) sleep(2000) speech.say("Hello,Twitter") sleep(2000) display.show(Image.HEART) sleep(2000) speech.say("Hello,CSHARP") sleep(2000) speech.say("Hello,FACEBOOK") sleep(2000) speech.say("Hello,I AM MICROBIT AND I CAN TALK") sleep(2000) speech.say("I LOVE YOU")
Now, after writing the code, let us see how can we flash it and run our code on Micro:bit. For this, after writing the code, just click on "Flash" button there.
The demo can be seen here.
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https://microbit.hackster.io/anish78/make-your-bbc-micro-bit-talk-using-micropython-7bdb10
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refinedweb
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0
Please I am working on AdultDataset for a classification task
I found out:
from dataset import AdultDataset
is giving the error below:
ImportError: cannot import name ‘AdultDataset’ from ‘dataset’
Import Relevant Libraries
import numpy as np import pandas as pd import matplotlib.pyplot as plt from sklearn.preprocessing import LabelEncoder from sklearn.model_selection import train_test_split import torch import torch.nn as nn import torch.optim as optim from torch.autograd import Variable from torch.utils.data import DataLoader from dataset import AdultDataset So when I am trying to create a 3 layer Feed Forward Neural network using pytorch that takes as input the a dataset entries and classifies if the individuals gains more or less than 50K (i.e., the fnlwgt label) starting with the code below I get error train_dataset = AdultDataset(X_train, y_train) test_dataset = AdultDataset(X_test, y_test) NameError Traceback (most recent call last) in 1 # Using norm_D01 2 ----> 3 train_dataset = AdultDataset(X_train, y_train) 4 test_dataset = AdultDataset(X_test, y_test) 5 NameError: name 'AdultDataset' is not defined
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https://discuss.pytorch.org/t/importerror-cannot-import-name-adultdataset-from-dataset/107623
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VB.NET 2.0 enables you to utilize overloaded operators, which not only are easy to implement but also can provide your classes with intuitive operators. Learn how to use this powerful feature.
Latest Basic Syntax Articles - Page 13
.
.NET Remoting Using a New IPC Channel
Learn a new way to handle .NET remoting.
Batched Execution Using the .NET Thread Pool
The .NET thread pool's functionality for executing multiple tasks sequentially in a wave or group is insufficient. Luckily, a Visual C++.NET helper method that uses other types within the System.Threading namespace provides this batch-execution model.
'Using' the IDisposable Interface
The IDisposable interface can be used for far more than just the releasing of memory and resources. Learn how to use the interface to ensure that post conditions of code blocks are always.
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https://www.codeguru.com/csharp/csharp/cs_syntax/72/
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Description
This plugin displays the text on signs for each player individual differently.
Right now, it only replaces "[PLAYER]" on the sign with the name of the player looking at it.
However, it also includes an API for developers of other plugins to easily add own, custom player-specific sign content.
So when two players look at a sign at the same time with "[PLAYER]" somewhere on it they will see a different text.
You don't believe me? Then test it out for yourself!
This could for example be used for individual greeting signs at your spawn. Your players will be amazed to see their own name on a sign!
Permission to create a sign with "[PLAYER]" on it: insigns.create.player
How this works
To achieve this the plugin manipulates the sign packet that is sent to a player.
But keep in mind, that each line can still only hold 15 characters. So if the text is longer, it will automatically cut it at the 15's character. If the next lines of the sign are empty, InSigns will try to continue there..
Quick Presentation by VariationVault
For plugin developers: easy-to-use API
Here is a small example of how you can use this in your own plugin to display player-specific values on signs.
1.) First of all: add the Individual_Signs send a player the text of a sign.).
- setLine(int index, String line) - Sets the line of text at the specified index.
- Note that lines longer than the allowed 15 characters will be either cut or continued in the next lines (if those are empty) AFTER the event is over.
- isModified() - Whether or not this event was already modified by some plugin.
- setCancelled(boolean cancelled) - If the event is cancelled the sign packet will not be sent to the player, leaving the sign blank.
- static method InSigns.sendSignChange(Player player, Sign sign) - Sends a SignUpdate-Packet to the specified player. Useful if you want to update certain signs periodically.
-.
Changelog
Notice
This plugin uses Hidendra's Metrics class to report usage stats to mcstats.org. This can be disable by setting 'metrics-stats' to false in the config.
Similar plugins
Are you looking for individual player heads? Then IndividualHeads might be the right plugin for you!
Facts
- Date created
- Sep 18, 2012
- Category
-
- Last update
- Jan 14, 2014
- Development stage
- Release
- Language
- deDE
- enUS
- License
- Curse link
- Individual Signs
- Downloads
- 16,581
- Recent files
- R: IndividualSigns v2.0 for CB 1.7.2-R0.2 Jan 14, 2014
- R: IndividualSigns v1.5 for 1.7.4 Dec 18, 2013
- R: InSigns v1.4 for 1.6.4 May 04, 2013
- R: InSigns v1.3 for 1.5.1 Apr 20, 2013
- R: InSigns v1.2 for 1.5.1 Mar 30, 2013
Authors
Relationships
- Required dependency
- ProtocolLib
As of this moment, V2.0 does not work on Spigot 1.8 and
Protocollib for 1.8 has been released at this website
@LethalWrath: Go
I hope and assume that ProtocolLib will keep functioning and maybe even getting maintained for the near future.
After that I will of course have to look for alternative ways of hooking into minecraft's packet sending.
ProtocolLib has now become INACTIVE on its plugin page, I was wondering what will happen will happen to this plugin?
@blablubbabc: Go
Ok, I moved the signs out of the way (to the paintball lobby), which will make it less likely for players to log in there. I guess I'll manage... :-)
Make sure to take a look at my Bukkit plugins!
@pgmann: Go
That is because paintball loads your player statistics in the background after you finished joining the server (for performance reasons).
And IndividualSigns only intercepts sign packets (which get sent immediately when you join the server). It doesn't keep track of it's affected signs, nor does it automatically update those signs (for performance reaons as well).
So your player statistics are not yet loaded when the server sends you the sign text, therefore it prints the '-not found-' thing instead.
I don't think that is that big of a problem though.
@blablubbabc: Go
I found a bug when using this plugin to display scores from your paintball plugin. If I log in looking at the signs they will display '-not foun' in red until I right click them or go away to another location.
How can i use this plugin for my paintball plugin, what do i need to write in the signs (PLEASE HELP !!!)
Well, thanks a lot for that API, I was just about to write own method to show individual signs, and I found that plugin, you saved a lot of my time =)
@xXBadeye: Go
The error with the + is very likly an issue of your String.matches() method which checks for regexes and the + has a special meaning for regexes.. So you will have to escape that character.
@blablubbabc: Go
Well, i hate spaming your comments but i got strange stack traces now. I have now (finaly) got it working, problem was that the plugin loaded BEFORE protocolLib and InSigns and taht i forgot the onEnable part :D Well, one more, strange packet error. The class is still the same as in the commend underneath.
Stack Trace aaa is being printed out (see class in my last comment), so the getValue is called. Something seems to be wrong with the "+" on the sign, but it should be okay since it is just a string, right?
Edit: Didn't refreshed the page, your comment came to late, but you figured the problems i had :)
Edit 2: Well, it worked with removing the "+" from the string check... this is realy weird. So the text got replaced with the correct value, but there are no chat colors yet :D &4 did not work, have you implemented something like that?
Edit 3: Tryed return (ChatColor.GREEN + "My text"); and it worked :> only problem are the god damm "+" :D
BFAK:100480,49aa403a2fb1dc2e65f6f3e43bf52c5ce23aab7229f6e7208a221b482655a1cf
|
http://dev.bukkit.org/bukkit-plugins/individual-signs/
|
CC-MAIN-2014-52
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refinedweb
| 1,002
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Creating new file and deleting file within application is one of the most common requirement in any enterprise system development, and there are various type of challenges like security, pre-exists file etc.
In this tutorial you will learn how to use C# FileInfo class for all file related operation. create and delete file in c# using fileinfo class.
In following example you will learn about Fileinfo class in C# .Net, How to create file, delete file using Fileinfo in C# .Net .
FileInfo class in .Net comes under
System.IO namespace.
The FileInfo class provides the almost same functionality as the static
System.IO.File class in .Net,
in FileInfo we have more to do on read/write operations on files by manually implementing code.
Here are some very useful properties and method of
System.IO.FileInfo class, best way to understand following properties of FileInfo class, create a new instance of FileInfo
//Create a new instance of FileInfo for specified file FileInfo fi = new FileInfo(@"D:\myfile.txt");Now simply type
fi., you will be able to see all properties and methods
Get the Directory name of the file (full path)
Get the DirectoryInfo object, there you can get all information about that Directory
c# fileinfo file exists example, this method will allow you to check if file exists.
string fileName = @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); if (fi.Exists) Console.WriteLine(fi.FullName);
Before you work with any file, you can check if file exists
string fileName = @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); Console.WriteLine(fi.Extension);
Get the file extension, like .txt etc.
string fileName = @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); fi.Create();
Creates a new file
string fileName = @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); fi.Delete();
Deletes the specified file permanently
Move any specified file to a new location, c# fileinfo move file
Encrypt the file so that other account user can't open the file
Decrypt the file that was encrypted by the same account it was Encrypted with
Gets a FileSecurity object of a specified file.
Replace the contents of a specified file, delete the original file, and create a backup of old file.
Create a StreamWriter object that appends text to the file instance of the FileInfo class.
Here we create a new file with some content in it, notice how to create byte array and how to write byte array using FileStream class.
// File name with full path string fileName= @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); // Create a new file using (FileStream fs = fi.Create()) { Byte[] txt = new UTF8Encoding(true).GetBytes("We are adding some text in the file"); fs.Write(txt, 0, txt.Length); Byte[] author = new UTF8Encoding(true).GetBytes("WebTrainingRoom.Com"); fs.Write(author, 0, author.Length); }
Before checking any file information we need to check if file exists, (Also learn how to get file name, extension, DirectoryName) otherwise it will throw null object reference error
// File name with full path string fileName= @"D:\application\myfile.txt"; FileInfo fi = new FileInfo(fileName); // to check if file exists if (fi.Exists) { // Get file name with full path string fullFileName = fi.Name; Console.WriteLine("File Name: {0}", fullFileName); // Get file extension string fileExtension = fi.Extension; Console.WriteLine("File Extension: {0}", fileExtension); // Get directory object DirectoryInfo directory = fi.Directory; Console.WriteLine("Directory: {0}", directory.Name); // Get directory name string directoryName = fi.DirectoryName; Console.WriteLine("Directory Name: {0}", directoryName); }
We also can set file permission using FileInfo class
|
https://www.webtrainingroom.com/csharp/fileinfo
|
CC-MAIN-2021-49
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refinedweb
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Elixir — Notes on Processes
I have recently started reading Elixir in Action. While I would not recommend the book for those new to Elixir, I definitely think it is a great resource for those that want to learn about what makes Elixir / Erlang special and what programming constructs are used to achieve concurrency, fault-tolerance, and scalability.
Saša Jurić does an incredible job of introducing how Elixir / Erlang achieve these goal, and it all starts with the idea of processes. Below are my high-level takeaways of Elixir in Action’s Chapter 5 — Concurrency Primitives:
Processes
- Processes are the basic building blocks of Elixir / Erlang’s concurrency and parallelism powers.
- Concurrency means that each processes runs in its own execution environment, without sharing any memory with any other process.
- Parallelism means that multiple processes can execute at the same time.
- The spawn/1 function is used to create new processes. The spawn/1 function takes a zero-arity function as its argument. As a result, we must use the closure mechanism to “pass” data into the new process being spawned:
def async(data) do
spawn fn ->
# Execute Something
# data variable is available here thanks to closure
end
end
- Because processes are concurrent — i.e., share no memory — data made available from Process A to Process B is a deep copy of the data. In the example above, the data variable is copied into the execution context of the spawned process.
- Processes communicate with one another via message passing. Messages can be sent to another process via the send/2 function.
- Messages sent to a process will be stored in that process’s mailbox until two things happen. First, the process must check its mailbox using the receive macro. Secondly, the message in the mailbox must match a pattern.
- While multiple processes can execute in parallel, each process is itself sequential. It is either processing a message, or it is checking its mailbox for a message.
|
https://medium.com/@StevenLeiva1/elixir-notes-on-processes-4d37636bc6c7
|
CC-MAIN-2018-47
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refinedweb
| 325
| 53.81
|
Journal tools |
Personal search form |
My account |
Bookmark |
Search:
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for Night Vision Camera
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http://www.ljseek.com/Night-Vision-Camera_s4Zp1.html
|
crawl-002
|
refinedweb
| 673
| 67.35
|
I create an unsigned int and unsigned char. Then I assign the -10 value, and the char remains unsigned and gives me a value of 246, but the unsigned int takes the -10 value.
#include <stdio.h>
int main ()
{
unsigned char a;
unsigned int b;
a=-10;
b=-10;
printf("%d\t%d\n", a,b);
}
246 -10
NetBSD
This is undefined behavior when you pass unsigned integers to
%d. Wrong format specifier is UB.
If you assign a negative value to an unsigned variable, it's fine and the value will be taken modulo
UINT_MAX + 1 (or
UCHAR_MAX + 1), so
(-10) % (UCHAR_MAX + 1) = 256 - 10 = 246, and
b is 4294967296 - 10 = 4294967286. Unsigned integral overflow is required to wrap-around.
When
printf is interpreting these numbers, it finds 246 is suitable for
%d, the format specifier for
signed int, and 4294967286 is reinterpreted as -10. That's all.
|
https://codedump.io/share/vOaY4wazv1Jb/1/why-unsigned-int-stills-signed
|
CC-MAIN-2021-21
|
refinedweb
| 149
| 68.4
|
How Random is randint()?
Well, I had my doubts about randint() so I decided to test it out. I whipped up a little code in order to do so.
<pre>
from random import randint
from console import clear
zero = one = two = three = 0
ergo = 0
clean = 0
while ergo < 1000000:
#Randomly choses 0,1,2,or3
spin = randint(0,3)
#Keeps track of how often a given number comes up
if spin == 0:
zero += 1
elif spin ==1:
one += 1
elif spin == 2:
two += 1
elif spin == 3:
three += 1
ergo += 1
clean +=1
#This prints what number ergo is at, in thousands
if clean == 1000:
clean = 0
clear()
print (ergo)
#Converts the tallies into percentages and then prints the results
y=0
rolls = [zero, one, two, three]
names = ["zero","one","two","three"]
for x in rolls:
spam = (x/1000000.0)*100
print (names[y]+":"+str(spam)+"%")
y += 1
</pre>
To explain what this program does, it randomly choses one of four numbers (zero, one, two, or three). It then keeps a tally of which number it choses. It proceeds to do this a total of one million times!
After the computation is complete, it turns the tallies into percentages and prints the results. Because there are four numbers, each number should appear 25% of the time. Here is the results from my most recent running:
<pre>
1000000
zero:25.0265%
one:24.9848%
two:24.9903%
three:24.9984%
</pre>
As you can see, each number appears (almost) 25% of the time. I'd say that randint() works pretty well.
Just a word to the wise, the program takes some time to run. Somewhere between five and ten minutes.
Cubbarooney
- eliskan175
Yeah I have done a similar program to this in the past. Actually that slight variance in your program is only due to the fact you didn't test enough population. It should eventually converge on 25% of the time.
Randint is very solid :)
That may be due to the fact the decimals are so small that the program rounds up. I plan on trying one billion (just for fun), but I need to make sure the iPad doesn't die on me XD
Either way, randint() is reliable (to say the least).
Cubbarooney
- eliskan175
To speed up the loop considerably, remove print and clear from the program. Printing a lot of times has the side effect of causing tremendous lag. I noticed this when debugging my games.
On my PC, I am able to get it to perform the 1 million loops in only 5 seconds. So I amped it up to 10 million..
zero:25.00252%
one:24.99031%
two:25.0049%
three:25.00227%
Time took: 50.25
As expected, 10 times longer. Sooo I can safely amp it up to 100 million and just wait 10 minutes:
zero:25.003407%
one:24.996334%
two:25.004265%
three:24.995994%
Time took: 528.875
It doesn't get much closer than that! I wouldn't suggest trying 1 billion since (on my computer) it would take 5000+ seconds.
If you want to see how long a loop runs, you can do something like this:
from time import time
start = time()
#insert program or loop here
print time()-start #print current time (in seconds)
You can always reset the start timer.
83 and 1/3 hours.... That would be quite some time!
And thanks for the tip on clear and print. I have another program that does a loop a lot, but it does print a bit. I'll see what I can cut. I assume sounds slow it down a bit too.
And thanks for the additional research!
Randint() is very solid!
Cubbarooney
|
https://forum.omz-software.com/topic/152/how-random-is-randint/3
|
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refinedweb
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I was certified in a lot of things but SharePoint. Today however I've finished my last SharePoint exam with succes. I've passed all WSS en Moss exams.
Up to the next ones!(Maybe the next round of MCM?)
Cheers,
Wes
In my life time I’ve only met three good managers and they share some common characteristics which made them so good at what they are doing. In this post I’ll try to determine what it is that makes them that good while writing..
Of course this post isn’t complete at all. The three good managers I met are far more complicated and interesting than I can describe in one blog post. Please add to my list using the comments if you like.
P.S. I would really like to thank Karin van Klink, Fred van Luttikhuizen and Beat Nideröst.
I have to admit. I am late! Much to late! I promised you all a DownloadAsZip feature for SharePoint in a few days and it took me more than a month. But finally it’s here. First have a look at what it’s actually all about.
Hover the images for explanation…
I’ve explained how to create the multi select button and how to create the download handler in two previous posts. So now I’m going to focus on the last part. The ‘DownloadAsZip’ buttons.
Let’s start with the easiest part. With the handler in place we can add custom actions to list items simply by adding some CustomAction elements to our Elements manifest file. Here’s what the elements.xml looks like:
<?xml version="1.0" encoding="utf-8" ?>
<Elements xmlns="">
...
<CustomAction
Id="{18A0608F-7917-4fa3-8164-18E81B55A551}"
ImageUrl="/_layouts/images/ICZIP.GIF"
Title="Download as Zip"
Description="Download all files in this folder and view as one zip"
RegistrationType="ContentType"
RegistrationId="0x0120"
Location="EditControlBlock">
<UrlAction Url="{SiteUrl}/_layouts/DownloadAsZip.ashx?List={ListId}&Item={ItemId}" />
</CustomAction>
Id="{175D475D-C962-4965-9C9B-7CAFBB36A669}"
Description="Download this file as zip"
RegistrationId="0x0101"
</Elements>
What this fragment does is that it adds two buttons to the edit control block. One for files (RegistrationId=”0x0101”) and one for folders (RegistrationId=”0x0120”). These custom actions simply redirect the client to the previously created DownloadAsZip.ashx with the correct query string values.
So this adds single item DownloadAsZip functionality to our SharePoint site.
The code for the DownloadAsZip button on the ListView level is somewhat more difficult but still not to complicated. The code looks like this:
//-----------------------------------------------------------------------
using System.Globalization;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Security;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
namespace Motion10.SharePoint2007 {
public class DownloadAsZipAction : MenuItemTemplate {
/// <summary>
/// Initializes a new instance of the <see cref="DownloadViewAsZipAction"/> class.
/// </summary>
public DownloadAsZipAction()
: base("Download as Zip", "/_layouts/images/ICZIP.GIF") {
base.Description = "Download selected files or complete view if no items selected.";
}
/// Sends the content of the control to the specified <see cref="T:System.Web.UI.HtmlTextWriter"></see> object, which writes the content that is rendered on the client.
/// <param name="output">The HtmlTextWriter object that receives the server control content.</param>
[AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)]
[SharePointPermission(SecurityAction.LinkDemand, ObjectModel=true)]
protected override void Render(System.Web.UI.HtmlTextWriter output) {
ListViewWebPart listViewWebPart = FindListView(this.Parent);
if (listViewWebPart == null) {
this.Visible = false;
}
if (this.Visible) {
string navigateUrl = string.Format(CultureInfo.InvariantCulture,
"{0}/_layouts/DownloadAsZip.ashx?List={1}&View={2}&Item=",
SPContext.Current.Web.Url,
listViewWebPart.ListName,
listViewWebPart.ViewGuid);
string clientClick = string.Format(CultureInfo.InvariantCulture,
"window.location = '{0}' + GetSelectedItemsString('WebPart{1}')",
navigateUrl,
listViewWebPart.Qualifier);
this.ClientOnClickScript = clientClick;
base.Render(output);
protected ListViewWebPart FindListView(Control parent) {
ListViewWebPart retVal = parent as ListViewWebPart;
if (retVal != null) {
return retVal;
if (parent.Parent == null) return null;
return FindListView(parent.Parent);
}
}
The code is pretty straightforward. We create a class that inherits the MenuItemTemplate class and we change the ClientOnClickScript property in the render method. What the result of this is, is that client will be redirected to the DownloadAsZip.ashx with the selected items in the querystring. The javascript is explained in one of the previous posts.
To add this button to the ListView we need to adjust our elements.xml a little. We actually add two more CustomAction elements in there.
<CustomAction
Id="{DE394AD0-0A8E-4e5c-B246-A498BA2A7FB2}"
Title="Download as Zip"">
</CustomAction>
The second one is to add the ‘Enable item selection’ button and the first one to add the ‘Download as Zip’ button. Pay attention to the RegistrationId again. We add this button only to lists that inherit from the Document Library.
Well if you read all of the posts you’ve noticed that this is a pretty complex feature. We have a dependency on the jQuery feature. A lot of JavaScript. A custom HttpHandler etc. etc.
If you don’t know how to create solution packages yourself. Or if you don’t have the time to read all posts and create your own packages you can download the motion10 SharePoint Solution Pack. I’ve updated the Share Point Solution Pack to contain all these and and some more features.
!Please be smart and test the solution package in a test environment!
Cheers and have fun,
You probably wondered why my blog has been quiet the last two weeks. Well, today my colleague Gijs in ‘t Veld and I published our white paper on BizTalk Server and SharePoint integration, describing best practices for providing a “face” to BizTalk Server. It describes three examples: Exception Handling, Manager Approval and BizTalk Dashboard.
We cover a lot of integration features of SharePoint so even if you are not interested in BizTalk at all, you might want to have a look at this whitepaper. It contains complete walkthroughs, tips and explanations, on:
You can download it here:.
Wesley
Sometimes I get a very simple question which results in a not so simple solution. And this was one of those.
“How can I download multiple files and or folder from a SharePoint list at once?”
My first response was to use ‘explorer view’ but it lacks a lot of functionality. How about filters or views applied? As soon as you select the explorer view, all filters are dropped. How about cross browser support? Explorer view is available on IE only. So explorer view is more an ‘all or nothing IE only’ solution.
The idea for another SharePoint customization was born….
Actually we’re dealing with two issues here. The first one is that we do not have a way to select multiple items from a SharePoint list view. The second one is to actually download those selected files.
I decided to really cut them loose. Because the feature of selecting multiple items could come in handy for other features than downloading as well. I can think of mailing them as attachment, deleting multiple items at once, send them to the repository etc. etc. etc.
First things first, so I solved the selection of multiple items in one of my previous posts. Today we’re going to create the code for our http handler.
Just to be short. We do NOT want to create a file on the server and then send it to the client and we definitely do NOT want to write the zip file to a memory stream before sending it to the client either for multiple reasons.
We have only one option left and that’s to create the zip stream on the fly and hook it to our response stream. We don’t have any timeout issues because the client will start to receive bytes right away. We don’t have any issues with file storage and cleanup and if we use a buffer of only 4k for our stream we don’t have any memory considerations left.
! Do keep in mind though that compacting a file does cost a lot of processing power. Unfortunately that’s not something we can solve. !
I can’t stress this out enough: Don’t use a Page to stream data to your client. Just don’t. It is an http handler indeed but it will introduce a lot of overhead for nothing. You should create your own class that implements the IHttpHandler interface. So that’s what we’ll do.
We need some query string variable in there for us to know which files to add to the zip. So let’s outline them:
So the start of the ProcessRequest method in our custom handler looks like this:
/// ) {
HttpResponse response = context.Response;
string fileName = string.Concat(DateTime.Now.ToFileTimeUtc(), ".zip");
string contentDisposition = string.Concat("attachment; filename=\"", fileName, "\"");
response.Clear();
response.ContentType = "application/zip";
response.AddHeader("Content-Disposition", contentDisposition);
response.Buffer = false;
NameValueCollection queryString = context.Request.QueryString;
string listId = queryString["List"];
if (string.IsNullOrEmpty(listId)) {
throw new WebException("Required query string parameter 'List' is not defined.");
string viewId = queryString["View"];
string itemsString = queryString["Item"];
We clear the response stream and add the necessary headers before we send any content to the response stream. I decided to use DateTime.Now.ToFileTimeUtc() as the proposed filename to the client. We simply extract the query string parameters and check if the required List parameter is indeed there. If not we throw a WebException which SharePoint will graciously handle for us.
! What’s very important to notice here is that we set response.Buffer to false. In this way, everything we write to the response stream will be sent to the client right away. If we don’t set response.Buffer to false… we’ll have memory issues in no time. !
Although the .NET framework has a DeflateStream class to compress streams it still lacks the creation of zip files. In order to create a zip file you need to create file headers and stuff so I decided to use another library for it. First I went for the SharpZipLib but it has a GPL license which is not always permissible in a company so I looked around a little and there’s a very good alternative in the form of DotNetZip. Have a look at the conversation I had with one of the guys over here on how to solve some issues with it. They are really helpful! I didn’t have the time to rewrite my initial version of DownloadAsZip but I probably will do so in the future.
For now the code is based on the SharpZipLib and the rest of the ProcessRequest method looks like this:
SPWeb currentWeb = SPContext.Current.Web;
SPList selectedList = currentWeb.Lists[new Guid(listId)];
using (ZipOutputStream zipOutputStream = new ZipOutputStream(context.Response.OutputStream)) {
zipOutputStream.SetLevel(9);
if (!string.IsNullOrEmpty(itemsString)) {
string[] items = itemsString.Split(',');
foreach (string item in items) {
int itemId;
if (int.TryParse(item, out itemId)) {
SPListItem listItem = selectedList.GetItemById(itemId);
switch (listItem.FileSystemObjectType) {
case SPFileSystemObjectType.File:
zipOutputStream.AddSPFile(listItem.File);
break;
case SPFileSystemObjectType.Folder:
zipOutputStream.AddSPFolder(listItem.Folder);
default:
throw new FileNotFoundException("No such file or folder.");
}
else {
SPView selectedView = selectedList.DefaultView;
if (!string.IsNullOrEmpty(viewId)) {
selectedView = selectedList.GetView(new Guid(viewId));
SPListItemCollection selectedItems = selectedList.GetItems(selectedView);
zipOutputStream.AddSPListItemCollection(selectedItems);
context.Response.End();
A few important things to notice.
In line 4 we create a ZipOutputStream and tie it to the OutputStream and on line five we set the compression level to the highest possible. Unfortunately there’s no documentation on what this does to performance and what’s the benefits in terms of compression ratio. It’s something we’ll still have to figure out.
And secondly we write files and folders to our (now zipped) response stream with the methods:
The guys of the SharpZipLib did not implement the methods to add SharePoint files to a ZipOutputStream. That’s something we have to do ourselves. I started with a few static methods to add items and I found myself passing the ZipOutputStream object continuously from one method to the other. With extension methods this is something we can refactor to a very nice and clean solution with virtualy no extra effort. So here’s the code for the accompanying ZipUtility class:
using System.IO;
using ICSharpCode.SharpZipLib.Zip;
namespace Motion10.SharePoint2007.Zip {
public static class ZipUtility {
/// Adds the SPListItemCollection to the zip output stream.
/// <param name="zipOutputStream">The zip output stream.</param>
/// <param name="listItemCollection">The list item collection.</param>
public static void AddSPListItemCollection(this ZipOutputStream zipOutputStream, SPListItemCollection listItemCollection) {
foreach (SPListItem listItem in listItemCollection) {
/// Adds the SPFolder to the zip output stream.
/// <param name="folder">The folder.</param>
public static void AddSPFolder(this ZipOutputStream zipOutputStream, SPFolder folder) {
zipOutputStream.AddSPFolder(folder, string.Empty);
/// <param name="path">The path.</param>
public static void AddSPFolder(this ZipOutputStream zipOutputStream, SPFolder folder, string path) {
path = Path.Combine(path, folder.Name);
ZipEntry entry = new ZipEntry(path + "/");
zipOutputStream.PutNextEntry(entry);
foreach (SPFile file in folder.Files) {
zipOutputStream.AddSPFile(file, path);
foreach (SPFolder subFolder in folder.SubFolders) {
AddSPFolder(zipOutputStream, subFolder, path);
/// Adds the SPFile to the zip output stream.
/// <param name="file">The file.</param>
public static void AddSPFile(this ZipOutputStream zipOutputStream, SPFile file) {
zipOutputStream.AddSPFile(file, string.Empty);
public static void AddSPFile(this ZipOutputStream zipOutputStream, SPFile file, string path) {
string filePath = Path.Combine(path, file.Name);
ZipEntry entry = new ZipEntry(filePath);
entry.DateTime = file.TimeCreated;
using (Stream fileStream = file.OpenBinaryStream()) {
byte[] buffer = new byte[4096];
int sourceBytes;
do {
sourceBytes = fileStream.Read(buffer, 0, buffer.Length);
zipOutputStream.Write(buffer, 0, sourceBytes);
} while (sourceBytes > 0);
Please take a look at the code carefully. What’s really important to notice here is that we always add one file at a time and while doing so we always have just one file stream opened inside a using statement(see AddSPFile method). Another important thing to notice is that we use a small buffer of only 4k. This is to make sure we don’t create a huge memory monster or choke SharePoint with many open file streams.
We have the code for the handler now but we have not yet registered this handler with IIS. There are two way to do so.
This time I decided to go for the last option. Because it has some minor advantages. The content of the DownloadAsZip.ashx file looks like this:
<%@ Assembly Name="SharePointSolutionPack, Version=1.0.0.0, Culture=neutral, PublicKeyToken=4a7cd02bdf107f7a"%>
<%@ WebHandler Language="C#" Class="Motion10.SharePoint2007.DownloadAsZipHandler" %>
This of course doesn’t contain any real code as that’s all in our DownloadAsZipHandler class.
I know I promised a complete solution in my previous post but you guys and girls have to wait a few more days for the button. This post will be way to long if I’ll go through the code for the DownloadAsZip custom action as well. Just bare with me for a few more days.
And please DO leave comments if you like or dislike anything you read on this blog. I’m always in for improvements.
I’m pretty convenient with SharePoint and MOSS but sometimes get bitten in the rear if I try to do something on autopilot. While working on a presentation about the combination of SharePoint and BizTalk I wanted to insert an Excel sheet in SharePoint to show some BAM data. This is simply a cube on analysis services. After doing all the stuff I normally do I expected all to work but BOOM!:
Oh no! Let’s go through the steps again.
But still it doesn’t work. I can use the connection from the library in Excel. I can view the sheet, but I can’t update the connection!
Viewed the SharePoint logs. Nothing in there. Viewed the event viewer. Nothing in there.
Hmmm… lets use SQL server profiler to see if we actually get to login to the database. Strange, I don’t see a trace for Audit login when I try to connect. Ok this tells us that it’s a SharePoint issue at first.
Ok, maybe it’s permissions. Allowed all authenticated users “Full control” to both the data connection library and the excel sheet but this is not the issue. Didn’t think it would be cause View rights are enough but ok. What else?
Going through a walkthrough can sometimes lead you to a forgotten step. If you decide to do a walkthrough please don’t be ignorant and perform and check each and every step and don’t skip one because you think you’ve done it correctly. The walkthrough I used is the Plan external data connections for Excel Services its a great resource which explains a lot of the details of Excel Services. I almost decided to skip the first step but fortunately I didn’t.
The first step tells you to go to the ‘Trusted data providers’ section and add your provider. I never had to do that before because this library contains most of the standard data providers already.
This time however I was developing all this on Windows Server 2008 with SQL Server 2008 and as you can see in one of the images above(step 6 and 8) we use the MSOLAP.4 provider and that’s not in there!!!
After searching for all this time it was just a matter of adding the data provider name to the trusted data provider library and it al worked like a charm!
I do hope this story / walkthrough is of any help to y’all. I took me quite some time to figure out. Next time I’ll definitely take all steps in a walkthrough!
Default a SharePoint list does not have an option to select multiple items and looks like this:
Today I’m going to show you how to create a feature that enables the selection of multiple list items to make it look like this(notice the checkboxes):
I decided to go with some jQuery to adjust the list on the client side and one action button that simply adds or removes the checkboxes from the list. It’s all not to difficult if we use jQuery. So here’s the JavaScript:
function CreateParentInputCheckBox(webPartId) {
return $("<th nowrap</th>").append(
$("<input type='checkbox' title='(de)select all items' />").attr("id", webPartId + "0")
.click(function() {
var checked = $(this).attr("checked");
$("[id^=" + webPartId + "_]").attr("checked", checked);
})
);
function CreateChildInputCheckBox(webPartId, itemId) {
return $("<td></td>").append(
$("<input type='checkbox' />").attr("id", webPartId + "_" + itemId)
.val(itemId)
.click(function() {
$("#" + webPartId + "0").attr("checked", $(this).attr("checked") && $("[id^=" + webPartId + "_]:not(:checked)").length == 0);
})
function AddCheckBoxesToListView(webPartId) {
$("#" + webPartId + " table.ms-listviewtable>tbody")
.find(">tr.ms-viewheadertr").prepend(CreateParentInputCheckBox(webPartId)).end()
.find(">tr:not(.ms-viewheadertr)")
.each(function() {
var itemId = $(this).find("td.ms-vb-title>table[id]").attr("id");
if (itemId) {
$(this).prepend(CreateChildInputCheckBox(webPartId, itemId));
}
});
function IsSelectable(webPartId) {
var selectableItems = $("#" + webPartId + " table.ms-listviewtable>tbody>tr:not(.ms-viewheadertr)>td.ms-vb-title>table[id]").length;
return selectableItems > 0;
function RemoveCheckBoxesFromListView(webPartId) {
$("[id^=" + webPartId + "_], #" + webPartId + "0").parent().remove();
function GetSelectedItemsString(webPartId) {
var selectedIds = new Array();
$("[id^=" + webPartId + "_]:checked")
.each(function() {
selectedIds.push($(this).val());
});
return selectedIds.join(",");
function ListItemSelection_ButtonClick(senderId, webPartId) {
//jQueryon mozilla does not work with namespaces. We have to work with plain old javascript here...
var sender = document.getElementById(senderId);
if (sender.getAttribute("remove")) {
RemoveCheckBoxesFromListView(webPartId);
sender.setAttribute("text" ,"Enable item selection");
sender.setAttribute("description", "Enable the selection of items.");
sender.removeAttribute("remove");
} else {
AddCheckBoxesToListView(webPartId)
sender.setAttribute("text", "Disable item selection")
sender.setAttribute("description", "Disable the selection of items.");
sender.setAttribute("remove", true);
function ListItemSelection_Init(senderId, webPartId) {
if (!IsSelectable(webPartId)) {
var sender = document.getElementById(senderId);
sender.parentNode.removeChild(sender);
We create this ListItemSelection.js file and add it to our layouts directory. I use WSPBuilder for it, but you can use whatever you like to use for it.
The JavaScript checks if there’s a title column with edit control block in the listview because this field will contain the id of the item. If not, the button is removed because we can’t do anything without an id.
“Which button?” you ask. We have to create a custom action button. We do need to have a custom action that registers the above mentioned JavaScript file and a startup script to verify we have a title column with edit control block. This isn’t that difficult at all. The code looks like this:
public class SelectItemsAction : MenuItemTemplate {
public SelectItemsAction()
: base("Enable item selection", "/_layouts/images/motion10/ListItemSelection.gif") {
base.Description = "Enable the selection of items.";
/// Raises an event after the control is loaded but prior to rendering.
/// <param name="args">An <see cref="T:System.EventArgs"></see> object that contains the event data.</param>
[AspNetHostingPermission(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[SharePointPermission(SecurityAction.LinkDemand, ObjectModel = true)]
protected override void OnPreRender(System.EventArgs args) {
base.OnPreRender(args);
if (this.ListViewWebPart == null) {
return;
if (!Page.ClientScript.IsClientScriptIncludeRegistered("ListItemSelection")) {
Page.ClientScript.RegisterClientScriptInclude("ListItemSelection", "/_layouts/ListItemSelection.js");
string startupScript = string.Format(CultureInfo.InvariantCulture,
"$(function(){{ListItemSelection_Init('{0}', 'WebPart{1}');}});",
this.ClientID,
this.ListViewWebPart.Qualifier);
Page.ClientScript.RegisterStartupScript(typeof(SelectItemsAction), this.ClientID, startupScript, true);
if (this.ListViewWebPart == null || this.ListViewWebPart.ViewType != ViewType.Html) {
string clientScript = string.Format(CultureInfo.InvariantCulture,
"ListItemSelection_ButtonClick('{0}', 'WebPart{1}')",
this.ClientID,
listViewWebPart.Qualifier);
this.ClientOnClickScript = clientScript;
private bool searchedForListView = false;
private ListViewWebPart listViewWebPart;
private ListViewWebPart ListViewWebPart {
get {
if (!searchedForListView) {
listViewWebPart = FindListView(this.Parent);
return listViewWebPart;
private static ListViewWebPart FindListView(Control parent) {
With this code we have a custom action class but it’s not bound to any list toolbar yet. That's what we'll do next.
In order to have this button available on lists we need to add a CustomAction to our features Elements.xml file. In my case I’m going to use the selected items to download them as a zip file. So I added this custom action to the "Download as Zip" feature. You can however use this custom action for any feature you can think of. Such as a DeleteMultipleItemsAtOnce feature. The elements.xml file looks like this:
As you can see we’ve added this custom action as the second element in our DownloadAsZip features Elements.xml file. In this particular case we've tight this action to document library lists. That's because we do not have any other feautres yet that use the selected items.
Once deployed we have this extra button that toggles item selection:
In my next post I’ll describe the DownloadAsZip feature which will contain a complete WSP file and source again which includes the SelectItemsAction. That feature uses the selected items to create a zip file.
Cheers and have fun!
I promised you all I'd be back with the JavaScript to finish the Virtual Earth web part. It took me a little bit longer because a colleague of mine had a great suggestion actually. He wondered if the map could maintain state on post back AND if he could then use this state values to filter lists. In that way he could filter a list of locations simply by dragging around the Virtual Earth map control. That sounded like a great feature to me so, I decided to implement this feature.
The problem is however that all this has become pretty big and complicated. Explaining all this is not really interesting and would be a very long read. I promised you guys the source code however so I feel I have to do something.
So I decided to give you guys a brief overview of how it all fits together AND the complete source code in case you would like to really investigate how it all works.
The only way for me to maintain state is through hidden fields. So we had to register no less than 4 hidden fields on the page. These 4 hidden fields maintain the the minimum longitude, the maximum longitude, the minimum latitude, and the maximum latitude. With these four values I restore the virtual earth map control by calling SetMapView
if (restorePosition) {
var savedView = map.GetSavedPosition();
if (savedView != null) {
map.SetMapView(savedView);
Saving these values isn’t that hard because you can attach an event with the Virtual Earth API but how to initiate a postback? We need a postback reference and some sort of trigger to call this function. I finished with a timer that get’s reset on every change and triggers after a given amount of time.
VEMap.prototype.ClearPostBackTimeout = function() {
if (this.postBackTimeout) {
clearTimeout(this.postBackTimeout);
VEMap.prototype.SetPostBackTimeout = function() {
this.ClearPostBackTimeout();
this.postBackTimeout = setTimeout(this.postBackEventReference, this.autoPostBackTimeout);
To use the values of our Virtual Earth control we need to get to SharePoint Designer and add parameters to our DataFormWebPart:
And then use these parameters in our filter criteria:
Do remember we filter our dataview web part with the values from our Virtual Earth web part. Unfortunately the dataview web part does not implement the ITableProvider interface or we could actually get the locations to display on the Virtual Earth webpart from our list. That would be extremely nice… maybe I will think of something to solve this.
The download contains all the source files you need. And a WSP ready to be installed right away. Notice that you’ll need to have two features. The jQuery feature and the Virtual Earth feature. The Virtual Earth feature has a dependency on the jQuery feature.
DISCLAIMER: The download is as is. There’s no warranty what so ever and if you prefer to use it, you do so at your own risk. You should look at this code as en example of how things could be done and not necessarily how things should be done.
I do hope you all like this motion10 Virtual Earth feature and that it will serve your needs. If you have any questions, like to submit improvements or get in contact with me, please feel free to add a comment. You can also contact me by clicking the Live Messenger button in the left sidebar of this page.
Sometimes I’m amazed and today is such a rare moment. This should be embedded in Visual Studio 2010 by default!
Have a look over here and get amazed. Trust me it works!
Ever wandered about how it would be if you could validate the input of your clients with some regular expressions? Roaming the internet searching for a solution you do find some guys and girls who write about the fact that they created a Regular Expression field for SharePoint but they don’t explain how they did it. In this post I’ll explain to you how to create such a field. Which isn’t to difficult.
This is something that bothers me for a long time. SharePoint developers seem to be the copy and paste masters of this universe. They forget design principles, act like robots doing what they’ve been told and forget to be creative.
When reading examples on how to create custom fields I’m having trouble not to cry. Everybody starts with a Field, a FieldControl and an UserControl. No matter what kind of field, that’s how it should be done. Next they copy the files to the correct location and they have a new field. Perfect, right? WRONG! PLAIN WRONG!
Each developer knows that if he’s about to create a class, the first thing he should do is to check whether there might be an existing class that implements most of the features already. If so, we inherit that class and create some extra methods and or properties. In our case we are going validate a string input by matching it with a regular expression. And SharePoint does have a great solution for string input already. It’s called SPFieldText.
So we need a class, that inherits from the SPFieldText and implements two extra properties: ValidationExpression and ErrorMessage:
using System;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;
/// <summary>
/// Field that validates it value by the given regular expression
/// </summary>
[Guid("92A8DAFE-92C5-407c-A1E6-7BF0C80FB904")]
public class SPFieldRegexMatch : SPFieldText {
/// Initializes a new instance of the <see cref="SPFieldRegexMatch"/> class.
/// <param name="fields">The fields.</param>
/// <param name="fieldName">Name of the field.</param>
public SPFieldRegexMatch(SPFieldCollection fields, string fieldName)
: base(fields, fieldName) {
base.MaxLength = this.MaxLength;
/// <param name="fields">An <see cref="T:Microsoft.SharePoint.SPFieldCollection"></see> object that represents the field collection.</param>
/// <param name="typeName">A string that contains the name of the field type, which can be a string representation of an <see cref="T:Microsoft.SharePoint.SPFieldType"></see> value.</param>
/// <param name="displayName">A string that contains the display name of the field.</param>
public SPFieldRegexMatch(SPFieldCollection fields, string typeName, string displayName)
: base(fields, typeName, displayName) {
/// Gets or sets the maximum number of characters that can be typed in the field.
/// <value></value>
/// <returns>
/// A 32-bit integer that specifies the maximum number of characters.
/// </returns>
new public virtual int MaxLength {
string propVal = this.GetCustomProperty("MaxLength") + "";
int retVal;
if(int.TryParse(propVal, out retVal)){
return retVal;
return 0xff;
set {
this.SetCustomProperty("MaxLength", value);
base.MaxLength = value;
/// Gets or sets the validation expression.
/// <value>The validation expression.</value>
public virtual string ValidationExpression {
get { return this.GetCustomProperty("ValidationExpression") + ""; }
set { this.SetCustomProperty("ValidationExpression", value); }
/// Gets or sets the error message.
/// <value>The error message.</value>
public virtual string ErrorMessage {
string retVal = this.GetCustomProperty("ErrorMessage") + ""; ;
if (string.IsNullOrEmpty(retVal)) {
retVal = string.Concat(this.Title,
" does not match the regular expression: ",
HttpUtility.HtmlEncode(this.ValidationExpression));
set { this.SetCustomProperty("ErrorMessage", value); }
/// Used for data serialization logic and for field validation logic that is specific to a custom field type to convert the field value object into a validated, serialized string.
/// <param name="value">An object that represents the value object to convert.</param>
/// A string that serializes the value object.
public override string GetValidatedString(object value) {
string retVal = base.GetValidatedString(value);
string textValue = base.GetFieldValueAsText(value);
if (!string.IsNullOrEmpty(textValue) && !string.IsNullOrEmpty(this.ValidationExpression)) {
Regex validationRegex = null;
try {
validationRegex = new Regex(this.ValidationExpression);
catch (ArgumentException) {
throw new SPFieldValidationException("The configured regular expression is not valid. Please contact an administrator of this list to correct the issue.");
if (!validationRegex.IsMatch(textValue)) {
throw new SPFieldValidationException(this.ErrorMessage);
return retVal;
As you can read in this code sample it’s all pretty straight forward. We use the GetCustomProperty and SetCustomProperty to save the SPFieldRegexMatch its properties and we override the GetValidatedString method to indeed validate our input.
Unfortunately SharePoint does NOT call the property its setter method so we can not validate the regular expression on input. Which is the reason why we validate the regular expression on validation.
We do have our custom field type but, how do we signal SharePoint that we have this lovely new field?
SharePoint has its fields defined in xml files in de template/xml folder which names start with ‘fldtypes_’. All we need to do is create an xml file named 'fldtypes_motion10.xml' and define our custom field like so:
<FieldTypes>
<FieldType>
<Field Name="TypeName">RegexMatch</Field>
<Field Name="ParentType">Text</Field>
<Field Name="TypeDisplayName">Single line of validated text</Field>
<Field Name="TypeShortDescription">Single line of validated text(regular expression validation)</Field>
<Field Name="UserCreatable">TRUE</Field>
<Field Name="Sortable">TRUE</Field>
<Field Name="AllowBaseTypeRendering">TRUE</Field>
<Field Name="Filterable">TRUE</Field>
<Field Name="FieldTypeClass">Motion10.SharePoint2007.SPFieldRegexMatch, SharePointSolutionPack, Version=1.0.0.0, Culture=neutral, PublicKeyToken=4a7cd02bdf107f7a</Field>
<RenderPattern Name="DisplayPattern" Type="Text">
<HTML><![CDATA[<span title="Regular Expression Match field by motion10">]]></HTML>
<Column HTMLEncode="TRUE" />
<HTML><![CDATA[</span>]]></HTML>
</RenderPattern>
<PropertySchema>
<Fields>
<Field Name="MaxLength"
DisplayName="Max Length:"
Required="TRUE"
MaxLength="3"
Min="1"
Max="255"
DisplaySize="3"
Type="Integer">
<Default>255</Default>
</Field>
<Field Name="ValidationExpression"
DisplayName="Validation Expression:"
MaxLength="500"
DisplaySize="35"
Type="Text">
<Default></Default>
<Field Name="ErrorMessage"
DisplayName="Error Message:"
</Fields>
</PropertySchema>
</FieldType>
</FieldTypes>
This xml is very straight forward as well. Just for fun I inserted a RenderPattern but that’s not necessary at all. Since we inherit from SPFieldText, we have our rendering templates already.
With the PropertySchema we define the editable properties for which the UI will be rendered automagically. So all that’s left to do is to create a new WSPBuilder solution, add the class and the xml file, built, deploy and we are finished!
P.S. the ValidationExpression and ErrorMessage properties are declared virtual with a reason. It’s very simple to override those properties and create a new special field. Like SPFieldEmailAddress for example:
/// Field that validates its value to check whether it is an email address
[Guid("D306F9F2-2CF2-4ff3-BA4D-CC1C51126DCC")]
public sealed class SPFieldEmailAddress : SPFieldRegexMatch {
/// Initializes a new instance of the <see cref="SPFieldEmailAddress"/> class.
public SPFieldEmailAddress(SPFieldCollection fields, string fieldName)
public SPFieldEmailAddress(SPFieldCollection fields, string typeName, string displayName)
/// <remarks>The setter is not implemented.</remarks>
public override int MaxLength {
return 255;
throw new NotImplementedException();
public override string ValidationExpression {
return @"^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$";
public override string ErrorMessage {
string retVal = string.Concat(this.Title,
" does not contain a valid email address.");
<Field Name="TypeName">EmailAddress</Field>
<Field Name="TypeDisplayName">Email address</Field>
<Field Name="TypeShortDescription">Email address</Field>
<Field Name="FieldTypeClass">Motion10.SharePoint2007.SPFieldEmailAddress, SharePointSolutionPack, Version=1.0.0.0, Culture=neutral, PublicKeyToken=4a7cd02bdf107f7a</Field>
<HTML><![CDATA[<span title="Email address field by motion10">]]></HTML>
|
http://weblogs.asp.net/wesleybakker/
|
crawl-002
|
refinedweb
| 5,523
| 51.24
|
NAME
on_exit - register a function to be called at normal process termination
SYNOPSIS
#include <stdlib.h> int on_exit(void (*function)(int , void *), void *arg); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): on_exit(): .
CONFORMING TO
This function comes from SunOS 4, but is also present in libc4, libc5 and glibc. It no longer occurs in Solaris (SunOS 5). Avoid this function, and use the standard atexit(3) instead.
SEE ALSO
_exit(2), atexit(3), exit(3)
COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at.
|
http://manpages.ubuntu.com/manpages/oneiric/man3/on_exit.3.html
|
CC-MAIN-2015-35
|
refinedweb
| 106
| 67.76
|
The last two years, the method and tool developed by Mikolov et al. (2013) for learning continuous word embeddings has gained a lot of traction. The model forms the basis for the study of Le & Mikolov (2014). In order to better understand the methods in that study, I believe it would be good to first present a brief overview of Word2vec. For this overview I gratefully make use of the excellent, in depth explanation of Word2Vec by Xin Rong (2014). To have a more complete understanding of the model, please have a look at that paper.
Word2Vec attempts to associate words with points in space. The spatial distance between words then describes the relation (similarity) between these words. Words that are spatially close, are similar. Words are represented by continuous vectors over $x$ dimensions. This example shows the relation between a number of words where each word is represented by a vector of two dimensions:
%matplotlib inline
import seaborn as sb import numpy as np words = ['queen', 'book', 'king', 'magazine', 'car', 'bike'] vectors = np.array([[0.1, 0.3], # queen [-0.5, -0.1], # book [0.2, 0.2], # king [-0.3, -0.2], # magazine [-0.5, 0.4], # car [-0.45, 0.3]]) # bike sb.plt.plot(vectors[:,0], vectors[:,1], 'o') sb.plt.xlim(-0.6, 0.3) sb.plt.ylim(-0.3, 0.5) for word, x, y in zip(words, vectors[:,0], vectors[:,1]): sb.plt.annotate(word, (x, y), size=12)
The displacement vector (the vector between two vectors) describes the relation between two words. This makes it possible to compare displacement vectors to find pairs of words that have a similar relation to each other. A famous example given in the original paper is the following analogy relation:
queen : king :: woman : man which should be read as
queen relates to
king in the same way as
woman relates to
man. In algebraic formulation: $v_{queen} - v_{king} = v_{woman} - v_{man}$. This technique of analogical reasoning can be applied to e.g. question answering.
Word2Vec learns continuous word embeddings from plain text. But how? The model assumes the Distributional Hypothesis that words are characterized by words they hang out with. We can use that idea to estimate the probability of two words occurring near each other, e.g. what is the probability of the following words, given Cinderella, i.e $P(w|\textrm{Cinderella})$?
import pandas as pd s = pd.Series([0.1, 0.4, 0.01, 0.2, 0.05], index=["pumpkin", "shoe", "tree", "prince", "luck"]) s.plot(kind='bar') sb.plt.ylabel("$P(w|Cinderella)$")
<matplotlib.text.Text at 0x1136f8e90>
Word2Vec is a very simple neural network with a single hidden layer. Have a look at the following picture (taken from Rong 2014). We'll get into more details in a moment.
The model considers each word $w_o$ in turn along with a given context $C$ (e.g. $w_O$=Cinderella and $C$=shoe). Now given this context, can we predict what $w_O$ should be? This is essentially a multiclass classification where we have as many labels as our vocabulary size $V$. Using softmax regression, we can compute a probability distribution $\hat{y}$ over the labels. The model attempts to minimize via Stochastic Gradient Descent the difference between the output distribution and the target distribution (which is a one-hot distribution which places all probability mass on the correct word). The difference between the two distribution is measured by the cross-entropy.
The neural network contains two matrics: $W$ and $W'$ of dimensions $V \times N$ and $N \times V$ respectively, where $V$ is the vocabulary size and $N$ the number of dimensions. Let's make this all a little more concrete with a small example. Say we have a corpus containing the following documents:
sentences = ['the king loves the queen', 'the queen loves the king', 'the dwarf hates the king', 'the queen hates the dwarf', 'the dwarf poisons the king', 'the dwarf poisons the queen']
We first transform these documents into bag-of-indices to enable easier computation:
from collections import defaultdict def Vocabulary(): dictionary = defaultdict() dictionary.default_factory = lambda: len(dictionary) return dictionary def docs2bow(docs, dictionary): """Transforms a list of strings into a list of lists where each unique item is converted into a unique integer.""" for doc in docs: yield [dictionary[word] for word in doc.split()]
vocabulary = Vocabulary() sentences_bow = list(docs2bow(sentences, vocabulary)) sentences_bow
[[0, 1, 2, 0, 3], [0, 3, 2, 0, 1], [0, 4, 5, 0, 1], [0, 3, 5, 0, 4], [0, 4, 6, 0, 1], [0, 4, 6, 0, 3]]
We now construct the two matrices $W$ and $W'$:
import numpy as np V, N = len(vocabulary), 3 WI = (np.random.random((V, N)) - 0.5) / N WO = (np.random.random((N, V)) - 0.5) / V
Each row $i$ in $W$ corresponds to word $i$ and each column $j$ corresponds to the $j$th dimension.
print WI
[[-0.11953936 0.161062 -0.03209868] [ 0.00244538 0.11746195 0.12607279] [-0.14451005 -0.14540946 0.12184834] [-0.15411106 -0.04843555 -0.06943384] [ 0.04241556 0.01833369 -0.01999708] [ 0.09488057 -0.06968794 0.02873621] [-0.02498429 0.00360255 0.05691627]]
Notice that $W'$ isn't simply the transpose of $W$ but a different matrix:
print WO
[[-0.04019078 0.00870839 -0.00461927 -0.0255281 -0.00184819 -0.017375 0.04739917] [ 0.00962237 0.05808629 -0.02183692 0.07120648 0.0051645 0.03994698 -0.002765 ] [-0.03059303 0.05618066 0.029233 0.04137082 0.03396673 -0.01705916 -0.01613436]]
With the two matrices in place we continue with computing the posterior probability of an output word given some input word. Given an input word $w_I$, e.g. dwarf and its corresponding vector $W_I$, what is the probability that the output word $w_O$ is hates? Using the dot product $W_I \cdot W'^T_O$ we compute the distance between the input word dwarf and the output word hates:
print np.dot(WI[vocabulary['dwarf']], WO.T[vocabulary['hates']])
0.000336538415207
Now using softmax regression, we can compute the posterior probability $P(w_O|w_I)$:$$ P(w_O|w_I) = y_i = \frac{exp(W_I \cdot W'^T_O)}{\sum^V_{j=1} exp(W_I \cdot W'^T_j)} $$
p_hates_dwarf = (np.exp(np.dot(WI[vocabulary['dwarf']], WO.T[vocabulary['hates']])) / sum(np.exp(np.dot(WI[vocabulary['dwarf']], WO.T[vocabulary[w]])) for w in vocabulary)) print p_hates_dwarf
0.14291402521
Word2Vec attempts to associate words with points in space. These points in space are represented by the continuous embeddings of the words. All vectors are initialized as random points in space, so we need to learn better positions. The model does so by maximizing the equation above. The corresponding loss function which we try to minimize is $E = -\log P(w_O|w_I)$. First, let's focus on how to update the hidden-to-output layer weights. Say the target output word is Cinderella. Given the aformentioned one-hot target distribution $t$, the error can be computed as $t_j - y_j = e_j$, where $t_j$ is 1 iff $w_j$ is the actual output word. So, the actual output word is Cinderella and we compute the posterior probability of P(pumpkin | tree), the error will be 0 - P(pumpkin | tree), because pumpkin isn't the actual ouput word.
To obtain the gradient on the hidden-to-output weights, we compute $e_j \cdot h_i$, where $h_i$ is a copy of the vector corresponding to the input word (only holds with a context of a single word). Finally, using stochastic gradient descent, with a learning rate $\nu$ we obtain the weight update equation for the hidden to output layer weights:$$W'^{T (t)}_j = W'^{T (t-1)}_j - \nu \cdot e_j \cdot h_j$$
.
Assume the target word is king and the context or input word $C$ is queen. Given this input word we compute for each word in the vocabulary the posterior probability P(word | queen). If the word is our target word, the error will be 1 - P(word | queen); otherwise 0 - P(word | queen). Finally, using stocastic gradient descent we update the hidden-to-output layer weights:
target_word = 'king' input_word = 'queen' learning_rate = 1.0 for word in vocabulary: p_word_queen = (np.exp(np.dot(WO.T[vocabulary[word]], WI[vocabulary[input_word]])) / sum(np.exp(np.dot(WO.T[vocabulary[w]], WI[vocabulary[input_word]])) for w in vocabulary)) t = 1 if word == target_word else 0 error = t - p_word_queen WO.T[vocabulary[word]] = (WO.T[vocabulary[word]] - learning_rate * error * WI[vocabulary[input_word]]) print WO
[[-0.06243581 0.14095147 -0.02669861 -0.04758839 -0.0239239 -0.03947435 0.02543349] [ 0.00263098 0.09964895 -0.02877623 0.06427316 -0.00177368 0.03300138 -0.00966859] [-0.04061539 0.11576201 0.01928528 0.03143168 0.02402065 -0.02701589 -0.02603086]]
Now that we have a way to update the hidden-to-output layer weights, we concentrate on updating the input-to-hidden layer weights. We need to backpropagate the prediction errors to the input-to-hidden weights. We first compute $EH$ which is an $N$ dimensional vector representing the sum of the hidden-to-output vectors for each word in the vocabulary weighted by their prediction error:$$\sum^V_{j=1} e_j \cdot W'_{i,j} = {EH}_i$$
Again using the learning rate $\nu$ we update the weights using:$$W^{(t)}_{w_I} = W^{(t-1)}_{w_I} - \nu \cdot EH$$
Let's see how that works in Python:
WI[vocabulary[input_word]] = WI[vocabulary[input_word]] - learning_rate * WO.sum(1)
If we now would recompute the probability of each word given the input word queen, we see that the probability of king given queen has gone up:
for word in vocabulary: p = (np.exp(np.dot(WO.T[vocabulary[word]], WI[vocabulary[input_word]])) / sum(np.exp(np.dot(WO.T[vocabulary[w]], WI[vocabulary[input_word]])) for w in vocabulary)) print word, p
king 0.135793930736 dwarf 0.143640274055 queen 0.141911808054 poisons 0.144219025126 loves 0.14461048255 the 0.1457335424 hates 0.144090937079
Figure taken from (Rong 2014)
The model described above is the CBOW architecture of Word2Vec. However, we assumed that the context $C$ was only a single input word. This allowed us to simply copy the input vector to the hidden layer. If the context $C$ comprises multiple words, instead of copying the input vector we take the mean of their input vectors as our hidden layer:$$h = \frac{1}{C} (W_1 + W_2 + \ldots + W_C)$$
The update functions remain the same except that for the update of the input vectors, we need to apply the update to each word in the contect $C$:$$W^{(t)}_{w_I} = W^{(t-1)}_{w_I} - \frac{1}{C} \cdot \nu \cdot EH$$
Let's see that in action. Again assume the target word is king. The context consists of two words: queen and loves.
target_word = 'king' context = ['queen', 'loves']
We first take the average of the two context vectors:
h = (WI[vocabulary['queen']] + WI[vocabulary['loves']]) / 2
Then we apply the hidden-to-output layer update:
for word in vocabulary: p_word_context = (np.exp(np.dot(WO.T[vocabulary[word]], h)) / sum(np.exp(np.dot(WO.T[vocabulary[w]], h)) for w in vocabulary)) t = 1 if word == target_word else 0 error = t - p_word_context WO.T[vocabulary[word]] = WO.T[vocabulary[word]] - learning_rate * error * h print WO
[[-0.08162148 0.25512914 -0.04589425 -0.06655692 -0.04307783 -0.05847402 0.0063956 ] [-0.02294998 0.25188627 -0.0543705 0.03898171 -0.02731232 0.00766842 -0.03505252] [-0.04383296 0.13491036 0.01606604 0.02825053 0.02080841 -0.03020226 -0.02922364]]
Finally we update the vector of each input word in the context:
for input_word in context: WI[vocabulary[input_word]] = (WI[vocabulary[input_word]] - (1. / len(context)) * learning_rate * WO.sum(1))
h = (WI[vocabulary['queen']] + WI[vocabulary['loves']]) / 2 for word in vocabulary: p = (np.exp(np.dot(WO.T[vocabulary[word]], h)) / sum(np.exp(np.dot(WO.T[vocabulary[w]], h)) for w in vocabulary)) print word, p
king 0.129518690596 dwarf 0.145150475243 queen 0.143019721408 poisons 0.145122173218 loves 0.146255939585 the 0.146300899102 hates 0.144632100847
Hopefully we know have a better understanding of how Word2Vec learns continuous word embeddings from texts. Note that in order to efficiently apply this algorithm to real texts, we need some more tricks which I won't cover here. For now I would like to proceed with the Paragraph Vector described in Le & Mikolov (2014).
The Paragraph Vector model attempts to learn fixed-length continuous representations from variable-length pieces of text. These representations combine bag-of-words features with word semantics and can be used in all kinds of NLP applications.
If you read the paper, I think it will be clear by now that the Paragraph Vector is only a very small extension of the original model. Similar to the Word2Vec model, the Paragraph Vector model also attemts to predict the next word in a sentence. The only real difference, as the paper itself states, is with the computation of $h$. Where in the original model $h$ is based solely on $W$, in the new model we add another matrix called $D$, representing the vectors of paragraphs:
A paragraph token can be thought of as yet another word token except that (at least in the paper) all paragraph vectors are unique, whereas word tokens share their vector representations among different contexts. At each step we compute $h$ by concatenating or averaging a paragraph vector $d$ with a context of word vectors $C$:$$ h = \frac{1}{C} \cdot (D_d + W_1 + W_W + \ldots + W_C)$$
The weight update functions are the same as in Word2Vec except that we now also update the paragraph vectors. This first model is called the Distributed Memory Model of Paragraph Vectors. Le & Mikolov present another model called Distributed Bag of Words Model of Paragraph Vector. This model ignores the context $C$ and attempts to predict a randomly sampled word from a randomly sampled context window.
Let's have a more detailed look at the DM Model. In addition to the matrix $W$ we need to randomly initialize a matric $D$ with dimensions $P \times N$ where $P$ is the number of paragraphs or whatever textual unit we use, and $N$ is the number of dimensions.
V, N, P = len(vocabulary), 3, 5 WI = (np.random.random((V, N)) - 0.5) / N WO = (np.random.random((N, V)) - 0.5) / V D = (np.random.random((P, N)) - 0.5) / N
Say out corpus consists of the following five sentences (paragraphs):
sentences = ['snowboarding is dangerous', 'skydiving is dangerous', 'escargots are tasty to some people', 'everyone loves tasty food', 'the minister has some dangerous ideas']
We first convert the sentences into a vectorial BOW representation:
vocabulary = Vocabulary() sentences_bow = list(docs2bow(sentences, vocabulary)) sentences_bow
[[0, 1, 2], [3, 1, 2], [4, 5, 6, 7, 8, 9], [10, 11, 6, 12], [13, 14, 15, 8, 2, 16]]
Next we compute the posterior probability for each word in the vocabulary given the concatenation and averaging of the first paragraph and the context word snowboarding. We compute the error and update the hidden-to-output layer weights.
target_word = 'dangerous' h = (D[0] + WI[vocabulary['snowboarding']]) / 2 learning_rate = 1.0 for word in vocabulary: p = (np.exp(np.dot(WO.T[vocabulary[word]], h)) / sum(np.exp(np.dot(WO.T[vocabulary[w]], h)) for w in vocabulary)) t = 1 if word == target_word else 0 error = t - p WO.T[vocabulary[word]] = (WO.T[vocabulary[word]] - learning_rate * error * h) print WO
[[-0.01599941 0.02135301 0.0927715 -0.00565041 -0.00361651 -0.01454073 0.02333261 0.00211833 0.00254255 0.02315315 -0.01917578 0.00724787 -0.00117272 -0.02043504 0.00593186 -0.0166333 -0.0306218 ] [ 0.0089237 -0.00397806 -0.13199195 0.02555059 -0.02095756 -0.00978333 0.01561624 0.03603476 -0.02114407 -0.01552016 0.01289922 0.00119743 -0.00112818 0.01708133 0.00765248 0.02442374 0.01109005] [-0.01205008 -0.03123478 0.05878695 0.02615259 -0.01025209 -0.00442044 0.00311309 0.01554668 0.02344194 0.00602561 -0.03117694 0.01368817 0.00858936 -0.00223242 -0.01141366 -0.01719967 -0.01400046]]
We backpropagate the error to the input-to-hidden layer as follows:
EH = WO.sum(1) WI[vocabulary['snowboarding']] = WI[vocabulary['snowboarding']] - 0.5 * learning_rate * EH D[0] = D[0] - 0.5 * learning_rate * EH
Le & Mikolov evaluate and investigate the performance of the paragraph vectors on a number of different tasks. I will briefly discuss them here.
In the first experiment, the authors address the task of sentiment analysis. They make use of the Stanford Sentiment Treebank Dataset which is a manually annotated data set containing 11855 sentences taken from the movie review site Rotten Tomatoes. Each sentence in the data set has been assigned a label on a scale of negative to positive. The task is to predict these labels.
Le & Mikolov train Paragraph Vectors using both the DM Model and the DBOW model. These two representations are concatenated for each training instance and fed to a Logistic Regression classifier that makes a prediction for each unseen test sentence. They compare the performance of the model to a number of different models:
Le & Mikolov then move on beyond the sentence level and evaluate their model on the IMDB data set. Training and testings follows the same procedure as before. The results presented below suggest a strong improvement compared to the other reported models:
The authors then turn to an experiment in Information Retrieval. They develop a task in which the goal is to predict which of three paragraphs isn't the result of the same query. They construct a data set on the basis of the search results of a search engine. For each query they create a triplet of paragraphs: two paragraphs are results from the same query and one is randomly sampled from the rest of the collection (result from a different query). The pairwise distances between each member of a triplet, should then reflect which two results belong to the same query and which snippet is the outlier. The following table shows quite convincingly how well the paragraph vectors are able to perform on this task compared to the other methods:
Although the proposed model is only a small step beyond the original word2vec model (and some of the writings is quite sloppy), I think it is a really clever one with much potential for many different applications. The ease with which the model can be applied to text pieces of variable length is perhaps the strongest advantage of the model.
No implementation was available (even not to the second author, which led to some serious doubts about the reproducability of the results:
After a nice series of discussion, the first author finally made a suggestion on how to improve the results and actually come to the same performance as reported in the paper:
It is applaudable for the authors to interact and respond to comments by the readers. On the other hand, if they would have developed an implementation similar to the original word2vec, this discussion (and the resulting doubts in the method) wouldn't have to take place. The authors report a number of hyperparameters in the paper, such as the window size and the number of dimensions of the vectors. However, some crucial parameters weren't mentioned (such as the use of hierarchical softmax verus negative sampling). Again, in order to reproduce the results, the authors must specify in much greater detail how they performed the experiments.
from IPython.core.display import HTML def css_styling(): styles = open("custom.css", "r").read() return HTML(styles) css_styling()
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https://nbviewer.jupyter.org/github/fbkarsdorp/doc2vec/blob/master/doc2vec.ipynb
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CC-MAIN-2020-29
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refinedweb
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Some platforms lack any PATH_MAX definition. This defines PATH_MAX to a
sensibly large size in such cases.
Also, add one to PATH_MAX for the null byte.
This LGTM.
From Linux' limits.h:
#define PATH_MAX 4096 /* # chars in a path name including nul */
I'd conclude that it is not necessary to reserve an additional char for the terminating nul.
While maybe safe in practice, I don't think this is a good idea from a security/software quality perspective. But we can define PATH_MAX for platforms we know the the value of.
E.g. in lib/External/CMakeLists.txt we already have
if(MSVC)
# In the Windows API (with some exceptions), the maximum length for a path is
# MAX_PATH, which is defined as 260 characters.
target_compile_definitions(PollyPPCG PRIVATE "-DPATH_MAX=260")
endif ()
Thanks for the comments, everyone. This was originally submitted to fix a rust-lang buildbot, which I've learned is based on CentOS 5.5 (yes). Anyhow, I've fixed the issue on that particular buildbot by defining PATH_MAX in C(XX)FLAGS. Thus this patch isn't needed anymore. Thanks again.
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http://reviews.llvm.org/D51634
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refinedweb
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Apr 21, 2009 06:14 PM|ton_vj|LINK
Can any one help me??
I am new to ASP and ASP.net (MVC).
I have written a Model, Controller and an ASP Page(view)
My page is very simple that it connects to an MS -Access database and fetch the data and show it on the page when i click the Load push button.
Here is my code//<div>Model Code...</div> <div>*****************</div> <div>using System.Data.SqlClient;</div> <div>using System.Data.OleDb;</div> <div>namespace MvcApplication1.Models</div> <div>{</div> <div>public class ss </div> <div>{</div> <div>public int PID { get; set; }</div> <div>public string FName { get; set; }</div> <div>public string LName { get; set; }</div> <div>public string Email { get; set; }</div> <div>public Double Phone { get; set; }</div> <div> </div> <div>public ss()</div> <div>{</div> <div>}</div> <div>public ss(int pid, String fname, String lname, String email, Double phone)</div> <div>{</div> <div>this.PID = pid;</div> <div>this.FName = fname;</div> <div>this.LName = lname;</div> <div>this.Email = email;</div> <div>this.Phone = phone;</div> <div>}</div> <div>}</div> <div>}</div> <div> </div> <div>=======================================================================</div> <div>Controller Code...</div> <div>********************</div> <div>using System.Web.Mvc.Ajax;</div> <div>using MvcApplication1.Models;</div> <div>using System.Data.OleDb;</div> <div>namespace MvcApplication1.Controllers</div> <div>{</div> <div>[HandleError]</div> <div>public class ssController : Controller</div> <div>{</div> <div>public ActionResult ss()</div> <div>{</div> <div>return View();</div> <div>}</div> <div>public ActionResult load1()</div> <div>{</div> <div>OleDbConnection mycon;</div> <div>OleDbCommand com;</div> <div>ss usr = new ss();</div> <div>mycon = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Documents and Settings\Vijay\Desktop\Proof Concept\Person.mdb;Persist Security Info=False");</div> <div>mycon.Open();</div> <div>com = new OleDbCommand("select * from person", mycon);</div> <div>OleDbDataReader dr = com.ExecuteReader();</div> <div>if (dr.Read())</div> <div>{</div> <div>usr.PID = dr.GetInt32(0);</div> <div>usr.FName = dr.GetString(1);</div> <div>usr.LName = dr.GetString(2);</div> <div>usr.Email = dr.GetString(3);</div> <div>usr.Phone = dr.GetDouble(4);</div> <div>}</div> <div>mycon.Close();</div> <div>ViewData.Model = usr;</div> <div>return View("ss");</div> <div>}</div> <div>}</div> <div> <div>=======================================================================</div> <div> ASP Page Code...</div> <div>***********************</div> <div><%@ Page</div> <div>protected void Button1_Click(object sender, EventArgs e)</div> <div>{</div> <div>form1.</div> <div><asp:Label</asp:Label></div> <div></td></div> <div><td align="left" valign="top" style="width:90%"></div> <div><asp:TextBox</asp:TextBox></div> <div></td></div> <div></tr></div> <div><tr></div> <div><td></div> <div><asp:Button </div> <div></td></div> <div></tr></div> <div></table></div> <div>================================================================================================================================</div> <div> </div> <div>I dont know to bring the data back from the controller to my Page for the Text Box PID.TEXT = </div> <div>Although if i use the following
<%= Html.TextBox("PID")%> // it works.<div><asp:TextBox</asp:TextBox> // not working...</div> <div>Can any one help me..</div> <div>Thanks in advance...</div> <div> </div> <div>R,</div> <div>VJ</div>
</div></div></div></div></div></div>
MVC C# Textbox MS-Access
Participant
946 Points
Apr 21, 2009 07:50 PM|pmourfield|LINK
I'm pretty sure that the problem is because you're trying to mix ASP.NET and ASP.NET MVC Code. If you go with ASP.NET MVC, just know that the <asp:*> controls won't work.You also may want to run through some of the tutorials at
.
It is possible to create hybrid applications that use both technologies, but I wouldn't recommend it for someone who's just starting out.
Apr 21, 2009 08:15 PM|ton_vj|LINK
Thanks Peter,
I have started learning ASP in less than a month and now I: > . Please let me know how to get the value from the controller on to my push button event and display in my web page textbox with out modifying the <asp:*>. ??
Thanks for the Help
R,
VJ
C# MVC Textbox contol - Help
Apr 21, 2009 08:27 PM|paul.vencill|LINK
VJ, Sorry to hear about so many pages, perhaps you're better off converting the whole hting to a regular web forms app?
While you *should* be able to get ahold of the Model property in the ViewPage and set a value from that equal to the text of a textbox, you're probably going to cause other problems elsewhere in yoru app, since textboxes and the like are built to use viewstate,
while the MVC framework does not provide viewstate, and things like postbacks and click events are alien to the MVC framework's infrastructure.
Apr 21, 2009 08:30 PM|levib|LINK
ton_vjI: > .
Then ASP.NET MVC probably isn't for you. Why not stick with the existing WebForms-based code if it seems to be working?
Apr 21, 2009 08:36 PM|ton_vj|LINK
Peter,
Thanks.. Can you show a sample piece of code for this... For to have better understanding..
R,
VJ
MVC C# MS-Access <asp:Textbox
Apr 21, 2009 08:39 PM|ton_vj|LINK
Hi
My project manager is specific about coding in MVC and ASP.net (C#). Initially i didnt understand the model, but now im getting bit hold on this. If you can help me in getting this solved it will be of gr8 help.
Thanks
VJ
C# MVC Textbox contol - Help
Apr 21, 2009 08:49 PM|levib|LINK
ton_vjMy project manager is specific about coding in MVC and ASP.net (C#).
If your project manager is asking you to use both ASP.NET MVC and the standard ASP.NET built-in controls, then he probably doesn't have a good grasp of what ASP.NET MVC is. These two things are fundamentally incompatible.
If you really, really need to use MVC and some type of server-side controls, you can find some experimental ones in the MVC Futures assembly on CodePlex. But they're nowhere near as powerful as it sounds like you need, e.g. they don't have built-in features like validation. See for more information.
Apr 21, 2009 08:50 PM|paul.vencill|LINK
Honestly, there's not an easy solution to your problem. 80 pages or no, your best bet is to learn the way the MVC framework is done right (if he's insisting on it) and then do it that way. Anything else will be a lot more work and probably not meet your
project manager's goals.
Apr 21, 2009 09:02 PM|ton_vj|LINK
Paul,
Ok,, How to call the function() that is there in the controller from my button click event../
Apr 21, 2009 09:13 PM|paul.vencill|LINK
You don't.
Please take heed of what everyone is telling you and get onboard with one architecture or the other.
What are the actual project requirements that are driving the decision to mix like this? You really need to educate your PM about each architecture and let them weigh the pro's and cons' of each, rather than going for a hybrid. The hybrid you're looking
at will wind up being the worst of both worlds.
Apr 21, 2009 09:13 PM|levib|LINK
Perhaps we should back up a bit here. Why is your project manager insistent on using the MVC framework for this project? The MVC framework offers several benefits like nicely-formatted URLs, separation of concerns, control over markup, unit testability, etc. If your manager is interested in only one or two of these, it might be possible to apply it to your WebForms application. For example, if your main concern is that you want nice URLs, it's possible to use Routing or IIS rewriting with your WebForms application without bringing MVC into the picture at all.
Apr 21, 2009 09:15 PM|paul.vencill|LINK
Levi said it much better than I did...
Apr 21, 2009 09:37 PM|ton_vj|LINK
Thanks Paul and Levi,
The problem here is i was asked to design all of the web pages (ofcourse only screens/Web pages) using ASP.net 3.5 this is what client asked for, but now one of my manager in my officer suggest the MVC and explained its benefits, so every one want to convert the existing pages into the MVC architecture and now as a only developer in this project i was asked to do a proof of concept to connect temporarily to the MS-Access database with the existing page and show the data( select, Insert, update and delete). Client will be using Oracle as the database and we will be accessing through stored procedures. So i guess i am gonna have tough time.
Note: None of us in my team knows ASP.net C#
Apr 21, 2009 09:42 PM|paul.vencill|LINK
That's pretty rough. The Oracle piece isn't a big deal; in fact if you follow the existing 'best practices' out there, you can keep that totally separate from the rest of the app, os that the app doesn't need to know about it (i.e. you'd pull it out of that controller and into a repository implementation project).
The converting from web forms to MVC will take some doing. I'd recommend getting other folks spun up on at least the view page part, or else recommending to outsource some piece of it for faster turn-around time. On the plus side, if you become the only
expert in the office on this stuff, you can be a real hero. ;)
Apr 21, 2009 09:46 PM|levib|LINK
See Paul's response above. :)
Additionally, what does the client want? It sounds like the client just wanted a traditional 3.5 WebForms application. Note that ASP.NET MVC isn't included in .NET Framework 3.5, so making an MVC project would force the client to take a dependency on the MVC binary. Is this acceptable for them?
Apr 21, 2009 10:08 PM|ton_vj|LINK
Hi,
Client bought an Patented application designed in classic ASP 1.0, they want that application to be re-engineered in ASP.NET 3.5 with code in C#, my manager made them to accept to code in MVC. Now we have to deliver the entire project in MVC.
MVC binary == > is this that an extra plugin or module required to be installed separatly ??
If yes ., they are ok with that...
In the Intrim i am not getting the modified vale from my ASP Page for the Field PID.. please see the code below and advice whether am i missing something in this...
Controller code..public ActionResult save(Users pid=@PID";OleDbCommand con = new OleDbCommand(myq, mycon);
con.ExecuteNonQuery();
mycon.Close();return View("ss");
}
ASP Page Code
<%= Html.TextBox("PID") %>
<tr> <td align="left" valign="top" style="width:100%"> <br /> <asp:Button
<br /> </td> </tr><br /> </td> </tr>
Here i have PID value =100050 in my web page, when i click Save it is not getting saved into my table Person, note person have only one Row of data,
When i debug @PID value is not showing, how to get that value from the Web page??
C# MVC Textbox contol MS Access
Apr 22, 2009 01:48 AM|paul.vencill|LINK
OK, I can't help but saying (again) that you really need to get ahold of someone full time that can help you w/ the architecture on this. Learning it at the same time as you're trying to deliver product on it is a recipe for disaster; both in terms of not satisfying the customer's request as well as the timeline.
that said, I'll help as much as I can. Take the time to read this in detail: It'll help a lot.
A few things leap out at me as being wrong here. First, unless I'm missing something, I don't actually see a form anywhere. You need a form to actually post to the controller in this situation. Something like this:
<% using (Html.BeginForm()){ %> <fieldset> <label for="PID">Personal ID</label> <%= Html.TextBox("PID") %>
<input type='submit' value='Save' /> </fieldset> <% } %>
Then on your Controller save method, if your model object (Users) has a PID property, the default model binder will push in your PID-named textbox into it. So you can do something like:
var pid = formdata.PID;
Not knowing your Db schema, I don't know what data type it is, but beofre you call ExecuteNonQuery, you'll need to add the PID in as a parameter, like so:
command.Parameters.Add("@PID", OleDbType.Char).Value = pid;
Again, none of this represents a 'best practice', but in the spirit of getting you past your demo, that should help you out.
Paul
Remember to mark as answered
Apr 22, 2009 07:05 PM|ton_vj|LINK
Thanks for every one,
I have now solved the probelm,
I use the following to get the values from my ASP web page and save it to the Ms-Access database.
publicActionResult save(ss firstname= \'"+formdata.FName+"\' where pid= "+formdata.PID;OleDbCommand con = new OleDbCommand(myq, mycon);
con.ExecuteNonQuery();
mycon.Close();return View("ss");
}
Again, i will try to convince my folks on how its impossible in mixing ASP and ASP.net MVC ..
Thanks for all your help and time.
C# MVC Textbox contol - Access database
Apr 23, 2009 03:04 AM|paul.vencill|LINK
One example of how to harden against SQL Inject would be to use the ADO.Net parameters, as shown in my example above.
Paul
Please mark as answered
20 replies
Last post Apr 23, 2009 03:04 AM by paul.vencill
|
http://forums.asp.net/t/1413667.aspx?C+MVC+Textbox+contol+Help
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A cache of next hop information. More...
#include <next_hop_resolver.hh>
A cache of next hop information.
BGP requires information regarding resolvabilty and metrics for next hops. This information is known by the RIB. Questions are asked of the RIB and the results are cached here. The RIB notes that questions have been asked and if the state of a next hop changes then this is reported back to BGP. In order to save space the RIB does not record information about each next hop but returns an address/prefix_len range for which the answer is valid.
Not only can the RIB report changes but can also report that a previous entry is totally invalid. In the case that an entry is invalid all the next hops need to be re-requested.
Add an entry to our next hop table.
Lookup by base address.
Lookup next hop.
Given a real prefix_len entry return a prefix_len entry.
Given a real prefix_len entry return a prefix_len entry.
Validate an entry.
add_entry creates an entry with no nexthop references. The assumption is that a register_nexthop will follow shortly after initial creation. It is possible due to a deregister_nexthop coming in while we are waiting for a response from the RIB that the register_nexthop never happens. This method checks that the specified entry is referenced and if it isn't it is deleted.
The NextHopEntry is indexed in two ways either by prefix_len or by real_prefix_len.
Both of these data structures need to be kept in sync.
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http://xorp.org/releases/current/docs/kdoc/html/classNextHopCache.html
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46394/how-to-do-api-log-validation-in-selenium
Hey Gopi, API log Validation is not directly possible from Selenium as Selenium automates only browser activities and APIs don't run on browser. You can automate API testing using variety of tools like Rest Assured (for testing REST APIs) or SOAP UI (for testing SOAP APIs). You can use some plugins in Selenium to do api log validation.
I hope this would resolve your query.
Hey Lalita, you can perform following steps ...READ MORE
using OpenQA.Selenium.Interactions;
Actions builder = new Actions(driver); ...READ MORE
First, find an XPath which will return ...READ MORE
Download the executable driver from: ChromeDriver Download Himanshu, its quite easy to access any ...READ MORE
Hi Charu, to install TestNG framework in ...READ MORE
OR
|
https://www.edureka.co/community/46394/how-to-do-api-log-validation-in-selenium?show=46452
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A stepper motor is a type of DC motor that works in discrete steps and used everywhere from a surveillance camera to sophisticated robots and machines. NEMA 17 stepper motor has a step angle of 1.8° that means it will take 200 steps for a 360° rotation. By changing the rate of the control signal applied, we can easily control the motor speed. Stepper motor can be operated in different step modes such as full step, half step, ¼ step by applying appropriate logic levels to microstep pins of stepper module. In our previous project, we controlled 28-BYJ48 stepper motor using Arduino. 28-BYJ48 has relatively lower torque than the other stepper motors like NEMA 14, NEMA17.
In this tutorial, we are going to control NEMA 17 stepper motor using Arduino and DRV8825 stepper module. We will also use a potentiometer to control the direction of the stepper motor to rotate it in clockwise and anti-clockwise direction. We previously controlled the same Nema17 stepper motor with A4988 stepper driver and Arduino.
Components Required
- Arduino UNO
- NEMA17 Stepper Motor
- DRV8825 Stepper Driver Module
- 47 µf Capacitor
- Potentiometer
Nema 17 Stepper Motor Driver- DRV8825
A stepper driver module controls the working of a stepper motor. Stepper drivers send the current to stepper motor through various phases.
The DRV8825 is a microstepping driver module similar to the A4988 module. It is used to control bipolar stepper motors. This Nema 17 stepper driver module has a built-in translator that means that it can control both speed and direction of a bipolar stepper motor like NEMA 17 using only two pins, i.e. STEP and DIR. STEP pin is used to control the steps, and DIR pin is used to control the direction of rotation.
Nema 17 motor driver DRV8825 has a maximum output capacity of 45V and ± 2.2 A. This driver can operate stepper motor in six different step modes i.e. full-step, half-step, quarter-step, eighth-step, sixteenth-step, and thirty-second-step. You can change the step resolution using the microstep pins (M0, M1 & M2). By setting appropriate logic levels to these pins, we can set the motors to one of the six-step resolutions. The truth table for these pins is given below:
DRV8825 Stepper Motor lockout
- Over-current shutdown
Difference between DRV8825 and A4988 Nema 17 Motor Drivers
A4988 and DRV8825 both have similar pinout and applications, but these modules have some differences in no. of micro steps, operating voltage, etc. Some key differences are given below:
- The DRV8825 offers six-step modes, whereas the A4988 offers five-step modes. Higher step modes result in smoother, quieter operation.
- Minimum STEP pulse duration for DRV8825 is 1.9µs, while for A4988 STEP pulse duration is 1µs.
- The DRV8825 can deliver slightly more current than the A4988 without any additional cooling.
- Location of the current limit potentiometer is different in both modules.
- The DRV8825 can be used with a higher voltage motor power supply.
- The SLEEP pin on the DRV8825 is not pulled up by default like it is on the A4988.
- Instead of the supply voltage pin, DRV8825 has FAULT output pin.
Circuit Diagram
Circuit diagram to control Nema 17 with Arduino is given in the above image. Stepper motor is powered using a 12V power source, and the DRV8825 module is powered via Arduino. RST and SLEEP pin both connected to the 5V on the Arduino to keep the driver enabled. Potentiometer is connected to A0 pin of Arduino; it. M0, M1, and M2 pins left disconnected, that means the driver will operate in full-step mode.
Complete connections for Arduino Nema 17 DRV8825 are given in below table.
Current limiting
Before using the motor, change the current limit of DRV8825 module to 350mA using the current limiting potentiometer. You can measure the current limit using multimeter. Measure the current between two points GND and the potentiometer and adjust it to the required value.
Code Explanation
Complete code with a working video to(800);
Now in the main loop, we will read the potentiometer value from A0 pin. In this loop, we are using two functions one is potVal, and the other is Pval. If the current value, i.e., potVal is higher than the previous value, the Nema17 stepper motor using the potentiometer. The complete working of the Nema 17 with Arduino is shown in the video below. If you have any doubts regarding this project, post them in the comment section below.
#include <Stepper.h>
#define STEPS 200
//#define dirPin 2
//#define stepPin 3
// Define stepper motor connections and motor interface type. Motor interface type must be set to 1 when using a driver:
Stepper stepper(STEPS, 2, 3);
#define motorInterfaceType 1
int Pval = 0;
int potVal = 0;
void setup() {
// Set the maximum speed in steps per second:
stepper.setSpeed(800);
// pinMode(stepPin, OUTPUT);
// pinMode(dirPin, OUTPUT);
}
void loop() {
potVal = map(analogRead(A0),0,1024,0,500);
if (potVal>Pval)
stepper.step(10);
if (potVal<Pval)
stepper.step(-10);
Pval = potVal;
}
|
https://circuitdigest.com/microcontroller-projects/control-nema-17-stepper-motor-with-arduino-using-drv8825-stepper-motor-driver
|
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refinedweb
| 840
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Opened 8 years ago
Closed 8 years ago
#4815 closed task (fixed)
Leading tabs in PyGit.py
Description
PyGit.py has a few lines with tab-based indention in this function:
def print_data_usage():
(Introduced in Rev.3268, replacing line 622 of Rev.3267)
Not sure whether this is a coding standards issue; it bit me in the rear when I was tweaking. Hence zero priority. Sorry in advance if this is irrelevant.
Attachments (0)
Change History (2)
comment:1 Changed 8 years ago by brentl
comment:2 Changed 8 years ago by hvr
- Resolution set to fixed
- Status changed from new to closed
Note: See TracTickets for help on using tickets.
Sorry, should have linked the file:
source:gitplugin/0.11/tracext/git/PyGIT.py
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https://trac-hacks.org/ticket/4815
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refinedweb
| 125
| 67.45
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Essentially I have a front end using AngularJS and a back end using Java. I need to be able to send a value from the front end via an input box to the back end to make use of in the Java.
I found a basic example, namely:
Java
package com.mkyong.rest;(); } }
HTML
JAX-RS @FormQuery Testing
I understand the @FormParam parts and how that works but what I don’t understand is how the @Path works as well as the @POST. Is this linked to the form action and is it that simple or is there some step in between?
A general explanation of how this works/if my assertions are correct would be appreciated.
What i got from your question you want to more about
and
@PATH
if yes. than
is tell you the type of request like
post, get, put, delete
etc. that means your addUser method call only when POST request come to server but path should correct. Now
@PATH
tells you about the URL to call
addUser
method, In your case
@Path("/user") public class UserService
means whenever a request come to /user it call you UserService class, further if we have multiple method in same class like adduser, deleteuser, getuser than you need to tell server which method call for URL so we put @PATH on method and our URL is form. Example
@POST @Path("/add") public Response addUser //URL for aboue method is /user/add @POST @Path("/delete") public Response deleteUser //URL for above method is /user/delete
I hope you under stand the URL mapping in webservice, you need more study about URL mapping in web service.
About
is also depende upon the web.xml configuration.
|
http://colabug.com/2110320.html
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refinedweb
| 285
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What’s the difference between
getPath(),
getAbsolutePath(), and
getCanonicalPath() in Java?
And when do I use each one?
The best way I have found to get a feel for things like this is to try them out:
import java.io.File; public class PathTesting { public static void main(String [] args) { File f = new File("test/.././file.txt"); System.out.println(f.getPath()); System.out.println(f.getAbsolutePath()); try { System.out.println(f.getCanonicalPath()); } catch(Exception e) {} } }
Your output will be something like:
test\..\.\file.txt C:\projects\sandbox\trunk\test\..\.\file.txt C:\projects\sandbox\trunk\file.txt
So,
getPath() gives you the path based on the File object, which may or may not be relative;
getAbsolutePath() gives you an absolute path to the file; and
getCanonicalPath() gives you the unique absolute path to the file. Notice that there are a huge number of absolute paths that point to the same file, but only one canonical path.
When to use each? Depends on what you’re trying to accomplish, but if you were trying to see if two
Files are pointing at the same file on disk, you could compare their canonical paths. Just one example.
In short:
getPath()gets the path string that the
Fileobject was constructed with, and it may be relative current directory.
getAbsolutePath()gets the path string after resolving it against the current directory if it’s relative, resulting in a fully qualified path.
getCanonicalPath()gets the path string after resolving any relative path against current directory, and removes any relative pathing (
.and
..), and any file system links to return a path which the file system considers the canonical means to reference the file system object to which it points.
Also, each of these has a File equivalent which returns the corresponding
File object.
getPath() returns the path used to create the
File object. This return value is not changed based on the location it is run (results below are for windows, separators are obviously different elsewhere)
File f1 = new File("/some/path"); String path = f1.getPath(); // will return "\some\path" File dir = new File("/basedir"); File f2 = new File(dir, "/some/path"); path = f2.getPath(); // will return "\basedir\some\path" File f3 = new File("./some/path"); path = f3.getPath(); // will return ".\some\path"
getAbsolutePath() will resolve the path based on the execution location or drive. So if run from
c:\test:
path = f1.getAbsolutePath(); // will return "c:\some\path" path = f2.getAbsolutePath(); // will return "c:\basedir\some\path" path = f3.getAbsolutePath(); // will return "c:\test\.\basedir\some\path"
getCanonicalPath() is system dependent. It will resolve the unique location the path represents. So if you have any “.”s in the path they will typically be removed.
As to when to use them. It depends on what you are trying to achieve.
getPath() is useful for portability.
getAbsolutePath() is useful to find the file system location, and
getCanonicalPath() is particularly useful to check if two files are the same.
The big thing to get your head around is that the
File class tries to represent a view of what Sun like to call “hierarchical pathnames” (basically a path like “c:/foo.txt” or /usr/muggins”). This is why you create files in terms of paths. The operations you are describing are all operations upon this “pathname”.
getPath()fetches the path that the File was created with (
../foo.txt)
getAbsolutePath()fetches the path that the File was created with, but includes information about the current directory if the path is relative (
/usr/bobstuff/../foo.txt)
getCanonicalPath()attempts to fetch a unique representation of the absolute path to the file. This eliminates indirection from “..” and “.” references (
/usr/foo.txt).
Note I say attempts – in forming a Canonical Path, the VM can throw an
IOException. This usually occurs because it is performing some filesystem operations, any one of which could fail.
I find I rarely have need to use
getCanonicalPath() but, if given a File with a filename that is in DOS 8.3 format on Windows, such as the
java.io.tmpdir System property returns, then this method will return the “full” filename.
|
https://exceptionshub.com/whats-the-difference-between-getpath-getabsolutepath-and-getcanonicalpath-in-java.html
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refinedweb
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Session Initiation Protocol (SIP)
is a signaling protocol that is used to set up, modify, and terminate a
session between two endpoints. SIP can be used to
set up a two-party call, a multi-party call, or even a multicast
session for Internet calls, multimedia calls, and multimedia
distribution.JSR 116: SIP Servlet API
is a server-side interface describing a container of SIP components or
services. SIP servlets, servlets that run
in a SIP container, are similar to HTTP Servlets, but also support the
SIP protocol. Together, SIP and SIP servlets,
are behind many popular telecommunications-based applications that
provide services such as Voice-over-IP (VoIP), instant
messaging, presence and buddy list management, as well as web
conferencing.
SIP and SIP servlets are also important in the enterprise. Combined
with Java EE technology, SIP servlets can be used to
add rich media interactions to enterprise applications.
JSR 289:
SIP Servlet v1.1 updates the SIP Servlet API
and defines a standard application programming model to mix SIP
servlets and Java EE components. SIP servlets are going to
play an even bigger part in building the next generation of
telecommunications services.
This Tech Tip covers some of the basic concepts underlying SIP and SIP
servlets. It also presents a sample
application that uses SIP servlets and HTTP servlets to provide VoIP
phone service.
What is SIP?
An easy way to describe SIP is to examine a usage scenario.
Let's say a user identified as A wants to set up a call with a user
identified as B. In a telecommunications
setting, user A and B would communicate through what are called user
agents. One example of a user agent is
a soft phone -- a software program for making telephone calls over the
Internet. Another example is
a VoIP Phone -- a phone that uses VoIP. Here are the steps that need to
happen to set up the call:
Figure 1 illustrates the steps in setting up a call.
SIP provides a standardized way of carrying out these steps. It does
this by defining specific request methods,
responses, response codes, and headers for signaling and call control.
The protocol has been standardized by
the Internet Engineering Task Force (IETF) underRFC3261
and is now accepted as the standard signaling protocol for the
3rd Generation
Partnership Project (3GPP) and as a permanent element
in theIP Multimedia Subsystem (IMS)
architecture.
How is SIP related to HTTP?
People often ask if SIP uses HTTP as the underlying protocol. The
answer is no.
SIP is a protocol that operates at the same layer as HTTP, that is, the
application layer, and uses TCP, UDP, or SCTP
as the underlying protocol. However, SIP does have a lot of
similarities with HTTP. For example, like HTTP, SIP is text based
and user readable. Also like HTTP, SIP uses a request-response
mechanism with specific methods, response codes, and headers.
A notable difference between HTTP and SIP is that the request-response
mechanism is asynchronous in SIP -- a request does not
need to be followed by a corresponding response. In fact, a SIP request
could result in one or more requests being generated.
SIP is a peer-to-peer protocol. This means that a user agent can act as
a server as well as a client. This is another
difference between SIP and HTTP. In HTTP, a client is always a client
and a server is always a server.
SIP supports the following request methods and response codes:
Request methods:
REGISTER. Used by a client to register an address
INVITE. Indicates that the user or service is being
ACK. Confirms that the client has received a final
INVITErequest.
INVITErequests.
CANCEL. Used to cancel a pending request.
BYE. Sent by a user agent client to indicate to the
OPTIONS. Used to query a server about its
Response codes:
1xx: Provisional. An
ACKthat
3xx: Redirection. Further action is required to
4xx: Client Error. The request contains incorrect
5xx: Server Error. The server failed to fulfill an
6xx: Global Failure. The request cannot be fulfilled
Session Description Protocol
Session Description Protocol (SDP) is a format for describing the media
format and type to be used in a multimedia session.
SIP uses SDP as a payload in its messages to facilitate the exchange of
capabilities between various user agents. For example,
the content of an SDP might specify the codecs supported by the user
agent and the protocol to be used such as
Real-time Transport Protocol (RTP).
SIP Message
Figure 2 shows the composition of a SIP message .
There are three major parts:
The SIP Servlet Model
The SIP servlet programming model is based on the servlet programming
model. It brings programming in SIP closer
to Java EE. Servlets are server-side objects that process incoming
requests and send an appropriate response to the client.
They are typically deployed in a servlet container and have a
well-defined life cycle. The servlet container is
responsible for managing the life cycle of the servlets within the
container and managing resources related
to technologies such as JNDI and JDBC that the servlet uses. The
servlet container also manages network connections for
servlets.
As mentioned earlier, SIP servlets are similar to HTTP Servlets, except
that they process SIP requests.
They do this by defining specific methods to process each of the SIP
request methods.
For example, HTTP servlets define the
doPost() method,
which overrides the
service() method,
to handle
POST requests. By comparison, SIP servlets
define a
doInvite() method, which also
overrides the
service() method, to handle
INVITE
requests.
JSR116
defined SIP Servlet API 1.0. It specified:
The initial SIP Servlet API specification is being revised by
JSR 289:
SIP Servlet v1.1.
SIP Servlet API -- Key Concepts
The key concepts that underlie SIP servlets are similar to those that
underlie HTTP servlets. The following
sections briefly describe some of those concepts.
SipServletRequest and
SipServletResponse
The request-response methodology in SIP is similar to that for HTTP
servlets. A request is defined in a
SipServletRequest object and a response in a
SipServletResponse
object.
However, only one
ServletRequest or
ServletResponse
object is non-null. That's because
a SIP request does not result in a symmetric response. There is also a
common super interface, called
SipServletMessage, for both
SipServletRequest
and
SipServletResponse objects.
The
SipServletMessage interface defines the methods that
are common to
SipServletRequest
and
SipServletResponse objects.
Figure 3 illustrates the hierarchy of the
SipServletRequest
and
SipServletResponse objects.
Servlet Context
The servlet context as defined in the servlet specification also
applies to SIP servlets. The servlet specification defines
specific context attributes that are used to store and retrieve
information specific to SIP servlets and interfaces from the
context. The servlet context can be shared with HTTP servlets within
the same application. This is explained in the
section Converged Applications.
Deployment Descriptor
An XML-based deployment descriptor is used to describe the SIP
servlets, the rules for invoking them, as well as
the resources and environment property used in the application. This
descriptor is in a
sip.xml file and
is similar to the
sip.xml
file is defined by an XML
schema.
SIP Application Packaging
SIP applications have the same packaging structure as web applications.
They are packaged in the JAR format with a file
extension of
.sar (Sip archive) or
.war (web archive).
Converged Context and Converged Application
An application may use both SIP and HTTP servlets to create a service.
To allow for HTTP and SIP servlets being in the same application
package, the SIP servlet specification
defines a
ConvergedContext object. This object holds the
servlet context shared
by both HTTP and SIP servlets and provides the same view of the
application to SIP and HTTP servlets in terms of
servlet context attributes, resources, and JNDI namespaces.
When an application includes both SIP and HTTP servlets it is known as
a converged application. This is in contrast
to a SIP-only application, which is called a SIP application. A
converged application is similar in structure to
a SIP application except that it has a
web.xml file as a
deployment descriptor in addition to
a
sip.xml file. In SIP Servlet API 1.1 (JSR289), the
concept of converged applications has been extended
to also cover enterprise applications. Enterprise applications can now
include a SIP application or a converged application
as a module. This type of enterprise application is called a converged
enterprise application.
SIP Sessions
The SIP servlet specification defines
SipSession objects
to represent a session over SIP in the same way as
HttpSession objects represent sessions over HTTP. Because
a single application such as a converged
application may have sessions over HTTP and SIP, the specification also
defines
SipApplicationSession, which
is a session object at the application level. The
SipApplicationSession
object acts as a parent to HTTP and
SIP sessions (that is, protocol sessions) in an application.
Annotations
Recall that the SIP Servlet API 1.1 aims to align SIP servlets with
Java EE 5. As a result, the specification
introduces the use of annotations defined by Java EE 5 within SIP
servlets and listeners. It also defines custom
annotations to represent interfaces defined by the SIP servlet
specification. The specification introduces the following
annotations:
@SipServlet. Used to indicate that a particular class is
@SipApplication. Used to define a SIP application. This
SipApplicationannotation can be used to create a logical collection of
@SipListener. Allows a particular class to be
SipListenerfor a particular SIP application. The name
@SipApplicationKey. A method level that helps define a
SipApplicationKeyfor a SIP application. The
SipApplicationKey
SipApplicationSessions.
Project Sailfin - an Open Source SIP Application Server
A SIP servlet container can be standalone, that is, supporting only SIP
servlets, or it can be a converged container
supporting both HTTP and SIP servlets. However, for most enterprise
uses, a SIP servlet container needs to be
a converged container within an application server.
Project Sailfin
is an effort to
produce an open source implementation of a SIP servlet container using
the
GlassFish
application server. The project is being
developed under java.net, with Sun and Ericsson as the major
contributors. Sailfin, the SIP servlet container
implementation in GlassFish being developed in the SailFin project,
supports SIP Servlet API 1.0 and aims to support
SIP Servlet API 1.1 when the specification is finalized.
The CallSetup Sample Application
The sample application for this tip, named CallSetup, is available as
part of the SailFin download. You can download
SailFin from theDownload SailFin Builds page.
Follow theSailFin Project - Instructions
to install and configure SailFin. The code for the CallSetup
application is in the
<sailfin-install-home>/samples/sipservlet/CallSetup
directory, where
<sailfin-install-home> is the directory where you
installed SailFin.
The CallSetup application uses SIP servlets and HTTP servlets to
provide VoIP phone service. The application
places VoIP calls with the help of a Back-to-Back User Agent (B2BUA)
SIP servlet. A B2BUA sets up a call between
two user agents by calling each user agent individually and then
connecting the two of them.
CallSetup Components
CallSetup includes the following components:
Registration.java. A plain old Java object (POJO)
RegistrarServlet. A SIP servlet that allows users to
RegistrationBrowserServlet.java. An HTTP Servlet
SipCallSetupServlet.java. An HTTP Servlet that sends
web.xml. Deployment descriptor for the HTTP servlets.
sip.xml. Deployment descriptor for the SIP servlets.
sun-web.xml. A product-specific deployment
persistence.xml. Defines the persistence unit.
Figure 4 shows the sequence of execution of the
application.
Let's look at some of the code in the components that comprise
CallSetup. Not all of the components for the application
are shown here and not necessarily all the code in each component.
You're encouraged to explore the entire code for the
application in the SailFin download.
RegistrarServlet.java
When a user agent sends a
REGISTER request, the
doRegister()
method is invoked and the
registration data is stored. A response with a status code is then sent
to the user agent.
RegistrationBrowserServlet.java
This is an HTTP Servlet that provides an interface to list registered
users and to set up calls between the two of them.
SipCallSetupServlet.java
This HTTP Servlet is called from the
RegistrationBrowserServlet
and
acts like a B2BUA by setting up a call between the two users.
B2BCallServlet.java
This SIP Servlet receives and handles the response to the
INVITE
request sent by
SipCallSetupServlet.
The servlet processes the response headers and body, gets the SDP, and
sends another
INVITE request to the
other user agent, along with the SDP metadata. After it receives the
response from other user with a success response
code, the servlet sets up the call between the two users.
sip.xml
The
sip.xml file defines the SIP servlets and specifies
their mapping. The mapping for a SIP servlet
uses the
equal,
and,
or, and
not
operators to define a condition
in which the servlet is invoked. In this case, the match is on the
request method being either
INVITE,
OPTIONS, or
persistence.xml
The
persistence.xml file defines the persistence unit,
EricssonSipPU,
which is used to persist
the registration data in the database. The application uses the default
JDBC resource available with Sailfin,
jdbc/__default.
Running the Sample Application
To run the CallSetup application, follow the instructions on theSailFin Project - Instructions
page. If you follow the instructions successfully, you should be able
to set up a call between two softphone clients.
The phone should ring sequentially at two selected end points.
Summary
This tip covered some of the basic concepts underlying SIP and SIP
servlets. It also presented a sample
application that uses SIP servlets and HTTP servlets to provide VoIP
phone service. And it introduced the SailFin
project, which is building an open source implementation of a SIP
servlet container using the GlassFish application server.
To learn more about SIP, SIP servlets, and the SailFin project, consult
the following resources:
Note that there is a NetBeans plugin available for SIP servlets, which
allows you to create a SIP application using
the NetBeans IDE. The plugin is available as a part of SailFin. You can
learn more about the NetBeans plugin
in the blog entryNetBeans 6.1 and Project Sailfin.
About the Author
Prasad Subramanian is a staff engineer at Sun Microsystems and is the
engineering lead for Project Sailfin.
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Great article!
Does this work only within an enterprise network? I'd like to have a Sailfin server running at my colo datacenter, and have home users use it to do voice conf / IM. Are there issues getting past home routers when the two users try to connect, or has that been solved somehow in the code?
At this time Sailfin works only within an enterprise network. To make home users connect to Sailfin directly via home routers, we may need a way to work around NAT issues. That is something that we want to solve in the next quarter. Stay tuned !
Try and listen to users@sailfin.dev.java.net AND dev@sailfin.dev.java.net
Thanks for asking !
--Prasad
Hi,
We have a custom SIP Stack developed using C. And they expose dll's for the SIP events. We need to develop a browser based IM client for voice chat using the SIP stack.
Is it possible to use SIPServlet?
Thanks in advance
Java_User
Hi Prasad,
Great introduction to Sailfin.
Are there any plans on adding the "voice" part of the signalling into the Sailfin project? Eg. the recent JSR 309 or like?
Thanks,
Soren
how can i communicate a sip-servlet with a http-servlet?
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