text stringlengths 1 1.11k | source dict |
|---|---|
reference-request, formal-grammars, context-free, parsing, software-testing
Title: Phrase generators for use with testing grammars that don't use a seed In helping someone understand phrase generators for use with testing grammars, think compiler test cases, I noted that I have never found a phrase generator that is knowledgeable of the grammar, and is deterministic. The phrase generators I am talking about rely on the grammar of the language as input so that the user does not have to recreate the rules for the grammar into a format acceptable for the tool. The tool must accept a BNF grammar; I don't mind if the grammar has to be factored some for the tool before input. Tools that rely on a seed or generate a random seed are what I want to avoid.
I am aware that one can use PROLOG to generate a parser and then run a query that outputs a set of results that are phrases used for testing. I also know that it is not uncommon for these result sets to have 10**15 answers for basic cases of a grammar like C++. | {
"domain": "cs.stackexchange",
"id": 491,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "reference-request, formal-grammars, context-free, parsing, software-testing",
"url": null
} |
Analysis. Mechanics of Materials 13-4d2 Beams Example 3 (FEIM): For the shear diagram shown, what is the maximum bending moment? The bending moment at the ends is zero, and there are no concentrated couples. In order to calculate maximum surface stress, you must know the bending moment, the distance from the neutral axis to the outer surface where the maximum stress occurs and the moment of inertia. The methods and procedures commonly used for finding forces resulting from applied forces are presented below. is gross defonnation progressing to rupture. (2) The cross section dimensions of the sheet are such so that the width to thickness ratio is large. Summing the moments give, Using the relationship between the bending stress and the radius of curvature, σ = -Ey/ ρ, gives,. Examples of a primary stress are circumferential stresses due to internal pressure & longitudinal bending stresses due to gravity. From the Torsion equation, we can calculate the Torsional stress and any other | {
"domain": "mariebourgeret.de",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.986363162714234,
"lm_q1q2_score": 0.8323870384822468,
"lm_q2_score": 0.8438950986284991,
"openwebmath_perplexity": 1476.45349171995,
"openwebmath_score": 0.6581926941871643,
"tags": null,
"url": "http://zgnd.mariebourgeret.de/bending-stress-formula.html"
} |
c++
Build finished with error(s). This error is because you are compiling C++ code with GCC (C compiler). The meaning of the error is that GCC can not find new and delete operators during the linking phase, which is because GCC does not link to the C++ standard library by default.
When compiling your C++ file, replace gcc with g++. It should be:
/usr/bin/g++ -g /path/to/file.cpp -o /path/to/desired_name
I just tried your code sample with g++, and it works with no problems.
If this is a small example, and you want to apply changes to a bigger project, the compiler should be correctly set in the package/project's CMakeLists.txt file. Please let me know if my suggestion did not fix this issue. | {
"domain": "robotics.stackexchange",
"id": 38916,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c++",
"url": null
} |
is not necessarily MST! Graph be G. let ’ s find all the spanning trees Clustering minimum bottleneck tree of G writing answers... Clustering ( Chapter 4.7 ) and minimum bottleneck spanning tree in which the most edge. Just decay in the graph are the trees with bottleneck edge in a spanning tree and it must have edge. Value of the textbook does not contain the minimal edge with largest cost in T. Shows the between! Minimum bottleneck spanning tree is the highest weighted edge in the next?. Post Your answer ”, you minimize the most expensive edge is as cheap as possible the recent invasion. Other answers tree of G back them up with references or personal experience Acts 1:14 i find it very.. To commuting by bike and i find it very tiring in an undirected graph (... Tree - Algorithm Mock Test question with detail Solution cheapest edge would be e! Help, clarification, or responding to other answers this be a spanning tree are three possible... Is in another language of lesser weight than | {
"domain": "com.br",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9755769106559808,
"lm_q1q2_score": 0.8150784460331487,
"lm_q2_score": 0.8354835350552603,
"openwebmath_perplexity": 940.2938443740902,
"openwebmath_score": 0.3927384912967682,
"tags": null,
"url": "http://julioperes.com.br/blooming-flower-cedsm/minimum-bottleneck-spanning-tree-4451a5"
} |
battery
Title: Guidelines for a "stopwatch based" craft I'm a swimmer and would like to create a small object that would help me folow my trainning plannification.
In other words I want to create a custum stopwatch, with 5 colored led that will be on or off according to the trainning program.
This is my training:
0:00 to 5:00 : Low Effort (Green light)
5:00 to 15:00 : Medium Effort (Yellow light)
15:00 to 20:00 : High Effort (Orange Light)
20:00 to 25:00 : Medium Effort (Yellow light)
25:00 to 26:00 : Maximum Effort (Red light)
26:00 to 30:00 : Low Effort (Green light)
30:00 Trainning done (Should turn off automaticaly.) | {
"domain": "robotics.stackexchange",
"id": 1172,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "battery",
"url": null
} |
Therefore $-(x + y) = -x + -y$
Explanations or rules used on each step:
1. $a + 0 = 0$
2. $a + (-a) = 0$
3. commutative and associative law
4. $a + (-a) = 0$
5. $a + 0 = 0$
## Proof of Lemma 2
Fill this part yourself.
## Proof of Theorem 1
This part is essentially the same as @amWhy's answer with a little bit more care to use only the basic axioms and the lemmas
$$\begin{eqnarray} -(2x + 1) & = & -2x + -1 & (1) \\ & = & -2x + 0 + -1 & (2) \\ & = & -2x + (2 + -2) + -1 & (3) \\ & = & (-2x + -2) + (2 + -1) & (4) \\ & = & -2 \times (x + 1) + 1 & (5) \\ & = & (-1 \times 2) \times (x + 1) + 1 & (6) \\ & = & 2 \times (-1 \times (x + 1)) + 1 & (7) \\ & = & 2y + 1 & (8) \\ \end{eqnarray}$$
Because $-(2x + 1)$ can be written in the form $2y + 1$, therefore $-(2x + 1)$ is an odd integer for any $x \in \mathbb Z$.
Explanations or rules used on each step: | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9706877717925422,
"lm_q1q2_score": 0.8151194959249042,
"lm_q2_score": 0.8397339696776499,
"openwebmath_perplexity": 355.84346631379634,
"openwebmath_score": 0.9768029451370239,
"tags": null,
"url": "http://math.stackexchange.com/questions/427256/prove-that-the-additive-inverse-of-an-odd-integer-is-an-odd-integer"
} |
homework-and-exercises, newtonian-mechanics
Title: How do I figure out how many N-m it takes to move a man on a skateboard? Given that the skateboard is on a flat surface, and let's say that the man weights 150lbs. How would I figure out how many N-m it takes to move that man? Does the wheel size matter?
Ignore friction of wheels and other environmental variables for a second, I am trying to figure out how one calculates how much N-m it takes to move a person? Are there other variables I need to know? | {
"domain": "physics.stackexchange",
"id": 25784,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "homework-and-exercises, newtonian-mechanics",
"url": null
} |
energy-conservation, momentum
Momentum must also be conserved in the y direction. For the particles after the collision, one particle moves up with a velocity the depends on the angle under which the collision took place, and the other particle moves down with this same velocity, ensuring that there is zero total y-momentum before and after the collision.
The velocity of each particle after the collision is the vector sum of the x and y components of each particle's velocity. This means that the final velocity of each particle after the collision must be greater than v/2. | {
"domain": "physics.stackexchange",
"id": 32780,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "energy-conservation, momentum",
"url": null
} |
java, parsing, swing
// skip first row that contains columns names
iter.next();
while (iter.hasNext()) {
Row r = iter.next();
String name = r.getCell(0).getStringCellValue();
String format = r.getCell(1).getStringCellValue();
Report currentReport = new Report(name, format);
new ProcessAndPrintTask(currentReport).execute();
}
}
catch (IOException exc) {
exc.printStackTrace();
}
}
}
private static void createAndShowGUI() {
JFrame mainFrame = new JFrame("Report Comparator");
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.add(new ReportTestGUI());
mainFrame.pack();
mainFrame.setVisible(true);
mainFrame.setVisible(true);
} | {
"domain": "codereview.stackexchange",
"id": 26886,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "java, parsing, swing",
"url": null
} |
image-processing, image-segmentation
Vein extraction from this image Your problem is quite different than the vein extraction one. In fact, it is much mucg easier to solve with the "geometric" definition of the Hough Transform.
The Hough Transform is used exactly to detect lines in an image. It achieves this by integrating the brightness values of an image towards some angle $\theta$. So, for example, for angle $\theta = 0 ^ \circ$, the Hough Transform produces the sum of each row in the image, for angle $theta = 90 ^ \circ$, the Hough transform produces the sum of each column in the image...and so on.
The combined result of this is that points map to arcs, lines map to points and polygons map to specific configurations of points in the Hough Space.
The way to pick up a line in the image, in the Hough Space, is ultra simple. You just pick a maximum. But, that would give you an infinite line, not a line segment, which is what you have in your application. | {
"domain": "dsp.stackexchange",
"id": 4913,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "image-processing, image-segmentation",
"url": null
} |
Mathematics Derivation of the formula for text()^nP_r and Permutations when all the objects are not distinct objects For CBSE-NCERT
Click for Only Video
### Topic covered
♦ Derivation of the formula for text()^nP_r.
♦ Permutations when all the objects are not distinct objects
### Derivation of the formula for text()^nP_r.
=>color(red)(text()^nP_r=(n!)/((n-r)!) , \ \ \ \ \ \ 0 ≤ r ≤ n)
Let us now go back to the stage where we had determined the following formula:
color(color)(text()^nP_r= n (n – 1) (n – 2) . . . (n – r + 1))
Multiplying numerator and denomirator by (n – r) (n – r – 1) . . . 3 × 2 × 1, we get
text()^nP_r= (n (n – 1) (n – 2) . . . (n – r + 1) (n – r) (n – r – 1) . . . 3 × 2 × 1 )/ ((n – r) (n – r – 1) . . . 3 × 2 × 1, )=(n!)/((n-r)!)
Thus color(blue)(text()^nP_r=(n!)/((n-r)!)) \ \ \ \ \ \ where 0 ≤ r ≤ n
This is a much more convenient expression for text()^nP_r than the previous one.
In particular, when r = n, | {
"domain": "exxamm.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9883127397667669,
"lm_q1q2_score": 0.8360556821435143,
"lm_q2_score": 0.8459424314825853,
"openwebmath_perplexity": 485.1969732226655,
"openwebmath_score": 0.7412874698638916,
"tags": null,
"url": "http://exxamm.com/blog/Blog/13926/zxcfghfgvbnm4?Class%2011"
} |
general-relativity, gravity, popular-science
To get an intuition about these timelike geodesics, picture the spatial diagram but flatten it out, without forgetting that the distances are distorted really, and then allow the vertical direction to represent time. A timelike geodesic extends upwards and turns towards the central axis. For a circular orbit it would be a helix. Imagine lots of little tick marks on this line, representing the ticking of a clock moving along it. If you fix the two ends of this line and then pull the middle of the line outward a little, there are fewer clock ticks along it because the clock has to move faster along the line and it gets a time dilation associated with this motion. If you push the middle of the line inwards a little, so that the clock takes a shortcut to its destination, then it can move more slowly, but now there is a gravitational time dilation that makes it tick slower on average. The line actually followed by the falling clock is the one which makes a compromise between these two | {
"domain": "physics.stackexchange",
"id": 72359,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "general-relativity, gravity, popular-science",
"url": null
} |
ros, buildfarm, rosdistro
Originally posted by lucasw on ROS Answers with karma: 8729 on 2016-03-03
Post score: 1
pending--There are no nodes with the label 'building_repository'
This was the result of a misconfigured repo/common.yaml (one of the ssh keys wasn't consistent with the master/common.yaml jenkins::private_ssh_key).
Upon trying to run reconfigure.bash repo a couple of times it looked like the change wasn't working. I ended up doing this on the repo machine:
rm -rf /var/log/puppet.log # Just to get a clean log, not necessary
sudo deluser jenkins-slave
sudo rm -rf /home/jenkins-slave
sudo su
./install_prerequisites.bash
./reconfigure.bash repo | {
"domain": "robotics.stackexchange",
"id": 23988,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "ros, buildfarm, rosdistro",
"url": null
} |
c#, sqlite, mvvm, uwp, entity-framework-core
Let's talk about it later when you have that many tables but for now in order to avoid a file with thousands of lines (which is highly unlikely) you should already start with different repositories. Now you have only the Respository which is not that bad by itself but it can be better. In your case it should be a PersonRepository. So now you have one for people. When you add more tables later I'm pretty sure you can come up with another repository for them. It doesn't have to always be one repo for a table. You have have repositories that are all about people and work internally with mutliple person-related tables. Then there might be repositories that work with other data like files etc.
Just don't put all your code in a single file. Group the talbles together by what makes more sense. | {
"domain": "codereview.stackexchange",
"id": 27473,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c#, sqlite, mvvm, uwp, entity-framework-core",
"url": null
} |
My question is: is this a well-known result of independent interest that is used in places other than in the proof of Hoeffding's Inequality, and if so, is it also known to extend to random variables with nonzero means?
The result that prompts this question allows asymmetric range $$[a,b]$$ for $$X$$ with $$a < 0 < b$$ but does insist on $$E[X] = 0$$. The bound is $$G(t) \leq e^{t^2(b-a)^2/8} = e^{t^2\sigma_{max}^2/2}$$ where $$\sigma_{\max} = (b-a)/2$$ is the maximum standard deviation possible for a random variable with values restricted to $$[a,b]$$, but this maximum is not attained by zero-mean random variables unless $$b = -a$$. | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9811668695588648,
"lm_q1q2_score": 0.8489292045690582,
"lm_q2_score": 0.8652240825770432,
"openwebmath_perplexity": 173.0046452376746,
"openwebmath_score": 0.9175314903259277,
"tags": null,
"url": "https://stats.stackexchange.com/questions/21141/bound-on-moment-generating-function"
} |
likely sequence of hidden states—called the Viterbi path—that results in a sequence of observed events, especially in the context of Markov information sources and hidden Markov models (HMM). Dynamic Programming Top-down vs. Default Risk and Income Fluctuations. This prob-lem has been thoroughly studied ever since, including extensions to jump-diffusion financial markets (see, e. Previously, I was expressing how excited I was when I discovered Python, C#, and Visual Studio integration. Additional Physical Format: Online version: Howard, Ronald A. At the time, t Read more… By John Russell. howard "dynamic programming and markov processes," Article in Technometrics 3(1):120-121 · April 2012 with 499 Reads How we measure 'reads'. Dynamic Programming and Markov Processes. Edit distance: dynamic programming edDistRecursiveMemo is a top-down dynamic programming approach Alternative is bottom-up. This lecture describes Markov jump linear quadratic dynamic programming, an extension of the method | {
"domain": "asainfo.it",
"id": null,
"lm_label": "1. Yes\n2. Yes",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9766692277960746,
"lm_q1q2_score": 0.8117518326123543,
"lm_q2_score": 0.8311430415844385,
"openwebmath_perplexity": 1282.145413049841,
"openwebmath_score": 0.23353199660778046,
"tags": null,
"url": "http://hvpj.asainfo.it/python-markov-dynamic-programming.html"
} |
Or, if estimates are needed, what is the worst one you need to apply to solve this?
• use letter $p$ instead of $n$. also since you explained what set P is you don't need to write out examples. just some tips to make the notation cleaner – qwr Mar 14 at 2:18
• there might be a way to use more complicated formulae for pi, but at the end your desired result is a numerical bound so you will probably eventually have to use a calculator somewhere. – qwr Mar 14 at 3:07
• @qwr Seems legit, it is then the question of who will find the answer with worsest bounds for $\pi$. – user757601 Mar 14 at 3:10
• you can use less precise bounds for pi if you are willing to calculate more terms or use some more cleverness (like Oscar Lanzi's answer where he used geometric series $6n \pm 1$). I give a simple answer. – qwr Mar 14 at 3:11
Among the various methods I tested, the following seems to be the "simplest", in terms of the arithmetic heights of the rational numbers involved. | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9648551576415562,
"lm_q1q2_score": 0.8181660688916341,
"lm_q2_score": 0.8479677622198947,
"openwebmath_perplexity": 621.8117307218866,
"openwebmath_score": 0.99110347032547,
"tags": null,
"url": "https://math.stackexchange.com/questions/3580298/happy-pi-day-is-it-true-that-sum-p-textprime-frac1-pip"
} |
memory-optimization, trie, zig
Side-note: I did something similar in C some time ago that might be of interest (algorithm-wise): Trie Implementation, Autocompletion, and Graph Visualization
In my application, changing the children array from 255 to 95 brought down the struct's size (the struct contained a bool field and the children array) from 1028 bytes to 384 bytes (I used 32-bit integers to store the indices in a dynamically growing pool of nodes. Previously, I was using 64-bit pointers, and the struct size had went down from 2056 bytes to 768 bytes). I should expect a similar reduction in your implementation too. | {
"domain": "codereview.stackexchange",
"id": 45528,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "memory-optimization, trie, zig",
"url": null
} |
Is it true that (or when is it true) $$\lim\limits_{N\to\infty}S_N=\int_0^\infty f(x)dx$$
Also the general term in \eqref{2} is $C_k=f\left(k\cdot\frac{1}{N}\right)$. How does it behave in the limit, namely $$\lim\limits_{N\to \infty}\lim\limits_{M\to \infty}f\left(M\cdot\frac{1}{N}\right)$$ | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9838471661250914,
"lm_q1q2_score": 0.8322780734721508,
"lm_q2_score": 0.8459424411924673,
"openwebmath_perplexity": 217.69898707063655,
"openwebmath_score": 0.9616981148719788,
"tags": null,
"url": "https://math.stackexchange.com/questions/2129293/transition-from-a-riemann-sum-to-an-integral"
} |
r
Title: Unable to use readline() for function() input I recently started learning R and was trying to make a script that would give specific values of a probability distribution. Ideally, in this script, there would be a list of probability distributions with an associated number. Users would be able to enter a number and it would print out a message while giving them a bunch of variables relevant to the specific probability distribution to enter.
This is my code:
DistriName <- readline(prompt = "Enter Distribution: ")
DistriName <- as.numeric(DistriName)
function(DistriName) {
if(DistriName = 1) {
print("You have selected the binomial distribution")
} else {
print("I am not familiar with the distribution. Sorry.")
}
}
For some reason, it keeps giving me this error:
Error: unexpected '}' in " }"
Error: unexpected '}' in "}"
I have checked multiple times for any missing opening brackets, but could not find anything. Try
if (DistriName == 1) | {
"domain": "datascience.stackexchange",
"id": 5294,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "r",
"url": null
} |
I suspect there is in general not much difference between GMRES and CG for an SPD matrix. Let's say we are solving $Ax = b$ with $A$ symmetric positive definite and the starting guess $x_0 = 0$ and generating iterates with CG and GMRES, call them $x_k^c$ and $x_k^g$. Both iterative methods will be building $x_k$ from the same Krylov space $K_k ... 4 The problem was in the underlying coupled PDE FEM model. This model includes a potential which is not fixed in any point, so any result potential = phi + C would be a solution, where C is an integration constant. I don't know why, but the direct solver (Matlab's \ using UMFPACK) finds a solution, where the iterative solver gets in massive troubles. I first ... 4 It looks like this paper is combining Hessian-free with truncated Newton method. Yes, it is. ...the approach is referred to as Hessian-free method. That is because the Hessian is never computed explicitly. Instead, the product of the Hessian and a vector is obtained using finite | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9585377261041521,
"lm_q1q2_score": 0.8028903349929343,
"lm_q2_score": 0.8376199633332891,
"openwebmath_perplexity": 430.34383636123397,
"openwebmath_score": 0.850691556930542,
"tags": null,
"url": "https://scicomp.stackexchange.com/tags/conjugate-gradient/hot"
} |
inorganic-chemistry, atoms, combustion, radicals
If it is reacted with water, carbohydrates form:
When reacted with alkenes, cumulenes are usually obtained:
They insert into C-Br and C-Cl bonds, but abstract fluorine from compounds containing C-F bonds.
More about this rather interesting chemistry can be read in "Reactive Intermediate Chemistry" by Robert A. Moss, Matthew S. Platz and Maitland Jones, Jr. | {
"domain": "chemistry.stackexchange",
"id": 9460,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "inorganic-chemistry, atoms, combustion, radicals",
"url": null
} |
the interest you earn each year is added to your principal, so that the balance doesn't merely grow, it grows at an increasing rate - is one of the most useful concepts in finance. He invested the remaining in a fund that paid compound interest, interest being compounded annually, for the same 2 years at the same rate of interest received Rs. Let’s find CI on a sum of Rs 8,000 for 2 years at 5% per annum compounded annually, then P 1 = Rs 8,000. The principal figure is in green. $1,000 at 14% for 30 years. It's good to practice with the rule of 72 to get an intuitive feeling for the way. Question 3. How much will the$20,000 be worth in 17 years if it is invested at 7% and compounded quarterly? 2. This interest is computed on the accumulated unpaid interest as well as the original principal. Suppose interest for first year be A and interest for second year is B , then the formula could be like: After getting the percentage of compound interest, we can find out the compound interest from | {
"domain": "cralstradadeiparchi.it",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9869795098861572,
"lm_q1q2_score": 0.815947592901234,
"lm_q2_score": 0.8267117855317474,
"openwebmath_perplexity": 1403.1439827840675,
"openwebmath_score": 0.4161606729030609,
"tags": null,
"url": "http://iptn.cralstradadeiparchi.it/compound-interest-pdf.html"
} |
ros, tutorial, rosmsg
rosmsg_debug(rospack, mode, arg, options.raw)
File "/opt/ros/lunar/lib/python2.7/dist-packages/rosmsg/__init__.py", line 450, in rosmsg_debug
print(get_msg_text(type_, raw=raw, rospack=rospack))
File "/opt/ros/lunar/lib/python2.7/dist-packages/rosmsg/__init__.py", line 427, in get_msg_text
package_paths = _get_package_paths(p, rospack)
File "/opt/ros/lunar/lib/python2.7/dist-packages/rosmsg/__init__.py", line 554, in _get_package_paths
results = find_in_workspaces(search_dirs=['share'], project=pkgname, first_match_only=True, workspace_to_source_spaces=_catkin_workspace_to_source_spaces, source_path_to_packages=_catkin_source_path_to_packages)
File "/opt/ros/lunar/lib/python2.7/dist-packages/catkin/find_in_workspaces.py", line 143, in find_in_workspaces
source_path_to_packages[source_path] = find_packages(source_path)
File "/usr/lib/python2.7/dist-packages/catkin_pkg/packages.py", line 86, in find_packages | {
"domain": "robotics.stackexchange",
"id": 29551,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "ros, tutorial, rosmsg",
"url": null
} |
time, causality, time-travel, randomness
Title: What would happen if you went back in time to get a random number? For example, you go to a website that generates a random number. You get the number 8. What would happen if you went back in time a few minutes, and repeated the same actions. Would you get the same number, or would it change? Your question brings up the ages old debate of the deterministic vs non deterministic nature of the universe.
Computers, by themselves, are incapable of coming up with a random number
because there is no mathematical function or algorithm that can produce a
random number. So, we programmers were stuck using what we call pseudorandom numbers, which are numbers generated by applying an algorithm to a seed number to turn it into a value that is as random as possible. | {
"domain": "physics.stackexchange",
"id": 29474,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "time, causality, time-travel, randomness",
"url": null
} |
partitions
In particular, you can design an easy linear-time greedy algorithm by observing that the sum of the numbers in each set of the partition must be exactly $T =\frac{1}{k} \sum_{i=1}^{n} a_n$.
Since all $a_i$ are integers, the answer can only be yes if $T$ is an integer. Moreover, since all $a_i$ are positive, either there is no index $j$ such that the elements in $\{a_1, a_2,\dots, a_j\}$ sum to $T$, or such a $j$ is unique.
In the latter case $\{a_1, a_2,\dots, a_j\}$ must be one of the sets of the partition, hence you can select it and repeat the above argument starting form $a_{j+1}$.
Here is the pseudocode of an iterative implementation of this algorithm, where a[i] represents $a_i$:
T = a[1] + a[2] + .... + a[n]
if T%n != 0:
return false | {
"domain": "cs.stackexchange",
"id": 21537,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "partitions",
"url": null
} |
python, python-3.x, tkinter
class ActivableButton(ButtonWithStatus):
STATUS = 'Status: {}'
def __init__(self, root, button_text, inactive_status, active_status):
super().__init__(root, 'left', {'padx': 10},
{'text': button_text, 'font': 'courier 20', 'bd': 0},
{'text': self.STATUS.format(inactive_status), 'font': 'courier 14'})
self.activated = False
self._active = active_status
self._inactive = inactive_status
def on_click(self):
self.activated = not self.activated
if self.activated:
self._status_config.update(text=self.STATUS.format(self._active), fg='blue')
else:
self._status_config.update(text=self.STATUS.format(self._inactive), fg='black')
self.label.configure(**self._status_config) | {
"domain": "codereview.stackexchange",
"id": 22752,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "python, python-3.x, tkinter",
"url": null
} |
quantum-algorithms, amplitude-amplification
With this circuit one can estimate the mean (of the $F(x_i)$) by measuring the probability of the extra qubit to be in state $|1\rangle$. Expressing the circuit as a single big-matrix operator would allow amplitude estimation to find the same results.
I've put a working version in Python (here). | {
"domain": "quantumcomputing.stackexchange",
"id": 4578,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "quantum-algorithms, amplitude-amplification",
"url": null
} |
# Calculate the 146th digit after the decimal point of $\frac{1}{293}$
The question is: Calculate the 146th digit after the decimal point of $\frac{1}{293}$
1 / 293 = 0,00341296928.., so e.g., the fifth digit is a 1.
We know that 293 is a prime, probably this would help us. I think an equation involving modulos has to be solved, but I am not sure how to tackle this.
Any help is appreciated! Could perhaps someone give a general method to solve these kind of problems?
EDIT: You are supposed to solve this without using a computer. | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9833429634078179,
"lm_q1q2_score": 0.843480232065366,
"lm_q2_score": 0.8577681068080749,
"openwebmath_perplexity": 298.25198836367633,
"openwebmath_score": 0.930730402469635,
"tags": null,
"url": "http://math.stackexchange.com/questions/108124/calculate-the-146th-digit-after-the-decimal-point-of-frac1293"
} |
beginner, c, parsing
//Array Indexes for dimension 2
int sweepA = 0;
int sweepB = 1;
int dwellA = 5;
int dwellB = 6;
int speed = 10;
int time = 11;
while (fgets (currentLine, MAX_STR_LENGTH, fp) != NULL)
{
//Convert line to uppercase to simplify string comparison
strupr (currentLine);
if (findWord (currentLine, "PERS NUM SPRAY_FUNCTION{80,15}"))
foundSprayFunctionArray = TRUE;
if (findWord (currentLine, "PROC SPRAY_POSITIONS()"))
foundSprayPositions = TRUE;
//If the sprayFunction array is found, read it
if (foundSprayFunctionArray)
{
// Loop through current line
for (i = 0; i < strlen(currentLine); i++)
{
ch = currentLine[i]; | {
"domain": "codereview.stackexchange",
"id": 35178,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "beginner, c, parsing",
"url": null
} |
rust
use std::io::Write;
fn main() {
while let Some(ary) = get_input() {
println!("{:?}", ary);
}
println!("Peace!");
}
fn get_input() -> Option<Vec<i16>> {
loop {
// Get user input.
print!("Enter series-> ");
std::io::stdout().flush().unwrap();
let mut input = String::new();
std::io::stdin().read_line(&mut input).unwrap();
// Parse it.
match input.trim() {
"q" => return None,
input => {
if let Ok(numbers) = parse_input(input) {
return Some(numbers);
}
}
}
}
}
fn parse_input(input: &str) -> Result<Vec<i16>, std::num::ParseIntError> {
input
.split_whitespace()
.map(|token| token.parse())
.collect()
} | {
"domain": "codereview.stackexchange",
"id": 27459,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "rust",
"url": null
} |
navigation, ros-kinetic, costmap, costmap-2d
obstacle_layer:
observation_sources: laser_scan_sensor
laser_scan_sensor: {sensor_frame: /sensor_link, data_type: LaserScan, topic: /navbot/scan_data, marking: true, clearing: true}
global_costmap_params:
global_costmap:
global_frame: /map
robot_base_frame: /platform
update_frequency: 5.0
static_map: true
plugins:
- {name: inflation_layer, type: "costmap_2d::InflationLayer", output: "screen"}
- {name: static_map, type: "costmap_2d::StaticLayer"}
- {name: obstacle_layer, type: "costmap_2d::ObstacleLayer", output: "screen"}
local_costmap_params.yaml:
local_costmap:
global_frame: /map
robot_base_frame: /platform
update_frequency: 8.0
publish_frequency: 4.0
rolling_window: true
static_map: false
width: 6.0
height: 6.0
resolution: 0.05
plugins:
- {name: inflation_layer, type: "costmap_2d::InflationLayer", output: "screen"}
- {name: obstacle_layer, type: "costmap_2d::ObstacleLayer", output: "screen"} | {
"domain": "robotics.stackexchange",
"id": 32437,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "navigation, ros-kinetic, costmap, costmap-2d",
"url": null
} |
java, interview-questions, matrix
public class MatrixTraverseCounterClock extends MatrixTraverse {
public MatrixTraverseCounterClock() {
super(TraverseDirection.DOWN);
}
public void traverseUp() {
decrementRow();
if (isUpLimitExceed()) {
incrementRow();
decrementCol();
decrementRightLimit();
moveLeft();
}
}
public void traverseLeft() {
decrementCol();
if (isLeftLimitExceed()) {
incrementCol();
incrementRow();
incrementUpLimit();
moveDown();
}
}
public void traverseDown() {
incrementRow();
if (isDownLimitExceed()) {
decrementRow();
incrementCol();
incrementLeftLimit();
moveRight(); | {
"domain": "codereview.stackexchange",
"id": 5459,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "java, interview-questions, matrix",
"url": null
} |
algorithm-analysis, runtime-analysis, trees, search-algorithms, graph-traversal
While we can consider the asymptotic behaviour of time- and space complexity, we cannot do the same for $b$, as it is a parameter that is not a function of $n$, so does not have asymptotic behaviour.
By $A$ is "proportional" to $B$, I mean that there are constants $c_1,c_2,c_3,c_4>0$ such that (for all values of $A,B$) we have $c_1\cdot B + c_2 \leq A \leq c_3\cdot B + c_4$. The difference between this notion and asymptotic notation ($\Theta, O, \Omega$ and such) is that $a,b$ do not have to be functions of a variable $n$ that represents the input size, although | {
"domain": "cs.stackexchange",
"id": 21746,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "algorithm-analysis, runtime-analysis, trees, search-algorithms, graph-traversal",
"url": null
} |
c#
public TaskWorker(Func<CancellationToken, Task> workerFunction, Action<Exception>? onErrorCallback = null)
{
_workerFunction = workerFunction ?? throw new ArgumentNullException(nameof(workerFunction));
_onErrorCallback = onErrorCallback;
}
public bool IsRunning { get; private set; }
public bool IsStarted { get; private set; }
public void Start()
{
if (_disposed)
{
throw new ObjectDisposedException(GetType().FullName);
}
lock (_syncLock)
{
if (_cancellationTokenSource != null)
throw new InvalidOperationException();
if (IsRunning)
throw new InvalidOperationException();
_cancellationTokenSource = new CancellationTokenSource();
_runningTask = Task.Run(() => WorkerFuncCore(_cancellationTokenSource.Token), _cancellationTokenSource.Token);
IsStarted = true;
}
} | {
"domain": "codereview.stackexchange",
"id": 41065,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c#",
"url": null
} |
c#, performance, sql, linq, .net-datatable
DUT_id = Convert.ToString(header.DUT_id),
Meas = (double)x.Meas,
x.Step,
x.LogID,
x.HeaderID,
printID = Convert.ToInt32(header.PrintID),
Prod_Blok = Convert.ToInt32(header.Prod_Blok),
Rep_Count = Convert.ToInt32(header.Rep_Count),
Operator = Convert.ToString(header.Operator),
}; | {
"domain": "codereview.stackexchange",
"id": 11284,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c#, performance, sql, linq, .net-datatable",
"url": null
} |
vectors, linear-algebra
$$p\cdot x = Et-\vec{p}\cdot\vec{x}$$
And as physicists already develop theories beyond the 4-dimensional space-time, it is also present in those higher-dimensional spaces. In Quantum mechanics the generalization of the dot-product is defined as bilinear form on the $\infty$-dim. Hilbert space. Briefly said, it is ubiquitous.
The story about the generalization of the cross-product is a bit more subtle. As generalization one uses the $\wedge$ (wedge)-product which is defined on the exterior algebra (also called Grassmann-algebra) of totally anti-symmetrical tensors. One defines spaces $\Lambda^p$ whose basis are exterior products of standard base vectors $\{e_1,\ldots, e_n\}$ of a n-dim. vector space $V$:
$$\{ e_{i_1}\wedge\ldots \wedge e_{i_p} | i_1 < \ldots <i_p \}\,\,\text{basis of}\, \Lambda^p \,\, p\leq n$$
$\Lambda^0$ is the set of real numbers and $\Lambda^1$ is the vector space $V$. | {
"domain": "physics.stackexchange",
"id": 62668,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "vectors, linear-algebra",
"url": null
} |
um y. Agora, poderemos deixar assim. If you view a as x squared-- 1/4, if you think about it, that's just 1/2 times 1/2. So the two things that pop out of my brain right here is that we can change the order a little bit because multiplication is both commutative-- well, the commutative property allows us to switch the order for multiplication. denominator other than that 4. So I'll show you the Khan Academy is a 501(c)(3) nonprofit organization. Percent word problems. get x squared times x squared, which is x to the fourth, this thing again. Anything we divide Simplifique raízes quadradas que contêm variáveis, como √(8x³) So the square root of this, although it's good, even if you do use this, to And then here you denominator is divisible by 12. 1400-1500 Renaissance in Italy and the North. by x is just x. x divided by x is 1. Now if you take the This expression 12, which you can also then simplify to that expression And it really just comes out And now we can do the Khan Academy is a | {
"domain": "krakow.pl",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9674102589923635,
"lm_q1q2_score": 0.8405119382629749,
"lm_q2_score": 0.8688267779364222,
"openwebmath_perplexity": 1590.547877463284,
"openwebmath_score": 0.6513517498970032,
"tags": null,
"url": "http://gr.krakow.pl/5ay80/multiplying-radical-expressions-khan-academy-af7a6c"
} |
wavelet
Title: How to turn Morlet wavelet into second generation wavelet? I have a very specific application which requires to use the complex Morlet wavelet (or Gabor wavelet, if that's the name you use). I currently use the convolution theorem to compute wavelets transforms, but I'm reading everywhere that direct wavelet transforms are more computer efficient, because of the lifting scheme.
On the other hand, I searched for lifting scheme, and it's so much of a different paradigm that I have no idea how to use it with my wavelet, or whether it's even possible. | {
"domain": "dsp.stackexchange",
"id": 775,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "wavelet",
"url": null
} |
pcl
Cheers,
Bastian
Originally posted by Bastian Steder with karma: 76 on 2011-03-06
This answer was ACCEPTED on the original site
Post score: 6
Original comments
Comment by Yianni on 2011-05-19:
Although a bit delayed, thanks for your answer.
Comment by sai on 2013-05-19:
What is the frequency at which NARF features can be extracted on Kinect data? | {
"domain": "robotics.stackexchange",
"id": 4950,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "pcl",
"url": null
} |
javascript, jquery, plugin, sliding-tile-puzzle
tile1 = _this.container.children().eq(Math.floor((Math.random() * (tilePuzzle.level * tilePuzzle.level)) + 1));
tile2 = _this.container.children().eq(Math.floor((Math.random() * (tilePuzzle.level * tilePuzzle.level)) + 1));
tile1Position = { 'top': tile1.css('top'), 'left': tile1.css('left') };
tile1.css({
'top': tile2.css('top'),
'left': tile2.css('left')
});
tile2.css({
'top': tile1Position.top,
'left': tile1Position.left
});
i++;
if (i > limit) {
clearInterval(timer);
}
}, 50);
}, 1000);
},
moveTile: function (tile, top, left) {
var _this, topDistance, leftDistance;
_this = this; | {
"domain": "codereview.stackexchange",
"id": 15370,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "javascript, jquery, plugin, sliding-tile-puzzle",
"url": null
} |
ros, 3d-navigation, pointcloud-to-laserscan, laserscan, velodyne
Originally posted by pwong on ROS Answers with karma: 447 on 2013-10-09
Post score: 0
I think pointcloud_to_laserscan is the usual solution for reducing 3D point cloud data for 2D mapping applications.
I've seen papers describing more elaborate schemes, depending on your environment and requirements.
Beware that the Velodyne does not see things nearer than 90cm away. See this discussion.
Originally posted by joq with karma: 25443 on 2013-10-10
This answer was ACCEPTED on the original site
Post score: 2 | {
"domain": "robotics.stackexchange",
"id": 15815,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "ros, 3d-navigation, pointcloud-to-laserscan, laserscan, velodyne",
"url": null
} |
c++, reinventing-the-wheel, pointers, c++20
Title: C++ std::shared_ptr implementation Took a shot at implementing std::shared_ptr, with a thread-safe refcount and weak count. Didn't do weak_ptr, I'm doing this for learning purposes, and I think from an educational standpoint there's not much to learn from adding it.
Also tried to implement the "we know where you live" optimization, with the control block and the underlying memory allocated together in makeShared, but it feels sloppy and error prone and would love advice on if it can be done more cleanly.
#include <atomic>
#include <iostream>
template <typename T>
class ControlBlock {
public:
ControlBlock():
m_ptr{nullptr},
m_ref_count{0},
m_weak_count{0}
{}
ControlBlock(T* ptr):
m_ptr{ptr},
m_ref_count{1},
m_weak_count{0}
{}
void add_reference() {
m_ref_count.fetch_add(1, std::memory_order_relaxed);
} | {
"domain": "codereview.stackexchange",
"id": 45008,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c++, reinventing-the-wheel, pointers, c++20",
"url": null
} |
meteorology, oceanography, wind, waves, scale
Shallow water wave processes like diffraction and refraction will curve the paths of the waves that start reaching the coast and "feeling the bottom". The waves appear to be heading almost perpendicular when they reach the coast, even if 1 km out to sea they're moving almost parallel to the long distance coast.
How the waves appear at the coast to the observer depends on the direction of the local wind. Generally, if the local wind blows in the same direction as the waves (i.e. onshore wind), the waves appear "mushy" as the wind helps to break the waves (see example image). If the local wind blows in the opposite direction of the incoming waves (i.e. offshore wind), the waves maintain their shape due to opposing wind and they break later (see example image). These conditions are favourable to surfers.
[1] Holthuijsen, L. H. Waves in oceanic and coastal waters. Cambridge University press, 2010. | {
"domain": "earthscience.stackexchange",
"id": 1986,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "meteorology, oceanography, wind, waves, scale",
"url": null
} |
My solution: 0=Theta | = integral. Orient the cylindrical hole through the sphere such that the axis of the hole is parallel and on the z axis.
||| r dzdrd0
Limits of integration (left to right): 0 to 2*pi, 1 to 3, -sqrt(9-r^2) to +sqrt(9-r^2)
My solution:
$\int^{2\pi}_{0}\int^{3}_{1}\int^{\sqrt{9-r^2}}_{-\sqrt{9-r^2}} r\,dz\,dr\,d\theta$
Is the expression correct?
Edited: I used wolfram to do the integration which yields $\frac{64\pi\sqrt{2}}{3}$. I crossed check this value with the online homework system and it says that this is correct.
O.K
Next, I'm going to try to verify this using spherical coordinates.
5. ## Re: Triple Integral: Volume problem, Using cylidrical coordinates | {
"domain": "mathhelpforum.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9752018369215508,
"lm_q1q2_score": 0.8189100999766692,
"lm_q2_score": 0.8397339596505965,
"openwebmath_perplexity": 1085.6736458065998,
"openwebmath_score": 0.8628122210502625,
"tags": null,
"url": "http://mathhelpforum.com/calculus/224925-triple-integral-volume-problem-using-cylidrical-coordinates.html"
} |
$$\cot(X)-\cos(X) = 0 \implies \frac{\cos X}{\sin X} - \cos X = 0 \implies \cos X\bigg(\frac{1}{\sin X} - 1\bigg) = 0$$ $$\implies \frac{\cos X(1 - \sin X)}{\sin X} = 0 \implies \cos X(1 - \sin X) = 0 \cdot \sin X = 0$$
This applies when $\sin X \neq 0$. If it is zero, then $\cot X = \infty$ so the equation is not satisfied. | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9820137910906878,
"lm_q1q2_score": 0.8287166270147367,
"lm_q2_score": 0.8438951005915208,
"openwebmath_perplexity": 268.85976551189276,
"openwebmath_score": 0.9592418670654297,
"tags": null,
"url": "https://math.stackexchange.com/questions/1921345/transforming-the-equation-cot-x-cos-x-0-into-the-form-cos-x1-sin-x"
} |
and height, of radius to get the arc length. More formally, a circular segment is a region of two-dimensional space that is bounded by an arc (of less than 180°) of a circle and by the chord connecting the endpoints of the arc. When degrees are the unit of angular measure, the symbol "°" is written. Arc length formula is used to calculate the measure of the distance along the curved line making up the arc (segment of a circle). The arc length is the product of the angular displacement and the radius of the circle, i. The top triangle is a right triangle, so knowing r and θ permits you to find x using cosine. So in the above diagram, the angle ø is equal to one radian since the arc AB is the same length as the radius of the circle. 19 radians, Arc Length = , Sector Area = We hope that the free math worksheets have been helpful. In a circle of radius 1, the radian measure of a given central angle can be This function will convert the quantities used to define a Polyline Arc segment | {
"domain": "brian229.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9867771759145343,
"lm_q1q2_score": 0.8244360832449217,
"lm_q2_score": 0.8354835350552604,
"openwebmath_perplexity": 296.86371070752983,
"openwebmath_score": 0.9140522480010986,
"tags": null,
"url": "http://brian229.com/8vpu/arc-radius-angle-formula.php"
} |
machine-learning, r, similarity, correlation
10 0.0034844717 0.09152440 4.589990e-04 5.802708e-07 Mark Rayman
11 0.0340738956 0.03384180 1.636508e-02 1.354973e-07 Mark FIFA
12 0.0266112679 0.20002020 3.380704e-02 4.533366e-07 Mark Sonic
14 0.0046597056 0.01848672 5.472681e-04 4.034696e-07 Paul FIFA
15 0.0202715299 0.16365289 2.994086e-02 4.044770e-07 Lucas SSBM | {
"domain": "datascience.stackexchange",
"id": 1395,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "machine-learning, r, similarity, correlation",
"url": null
} |
html, css
There is some jQuery to action this but I'm not concerned with this at the moment. I'm aware that SASS may simplify this but I'm not comfortable with that yet. Multiple nav elements
While multiple nav elements are allowed for any given section, it looks dirty to me. Consider using a single nav instead. If you need an extra element as a style hook, then use div or section.
Duplicate content
Having content that is only visible to mobile users and similar content that's only visible for desktop users is code smell. This one is extra bad because it uses identical markup for both. Just use one set of markup and have CSS style it differently depending on the viewport.
Using px for the width of text elements | {
"domain": "codereview.stackexchange",
"id": 11266,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "html, css",
"url": null
} |
induction, radio-frequency
It is step 4. that I am most confused by. Sources I've read simply say the load impedance is "felt" by the primary coil, whatever that means.
Also, what is the function of having a separate transmit and receive antenna on NFC transceivers? Partial answer:
When a resonant coil is "unloaded " the current and voltage will be in quadrature (90 degrees out of phase). If you bring a "load" into the vicinity of the coil, this will bring the current more in phase with the voltage (it does work on the load). So if you have a passive secondary coil that can only change how "visible" it is (by changing its impedance) then the primary could can feel this because it sees a phase shift.
The simplest way to change impedance is with a tiny switch that opens and closes the loop, obviously.
I can't answer the part of the question about separate antennas. | {
"domain": "physics.stackexchange",
"id": 23359,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "induction, radio-frequency",
"url": null
} |
Calculator. where R is the region bounded by the ellipse 16x^2+4y^2=64. Hypotrochoids are even more interesting though, since the spinner distance gets to be greater than the inner rotating circle if you want it to be. You need to introduce a phase shift to get a rotation. This one from a GMAT student: "I did tell you that I ended up with 690 on the GMAT, right? It was a good score for my purposes. [4] 2020/08/08 01:29 Male / 20 years old level / High-school/ University/ Grad student / Useful /. Those bottom three lines definitely look intimidating, but for any constant value of , each is just a linear equation in a, b, and c. There are a whole stack of the polar / cartesian questions on page 1815,. 0; // How many pixels before the wave repeats float dx; // Value for incrementing X, a function of period. The ellipse is first rotated about the. This is a two part lesson, an experiment and simulation that together meets the CCSSM S. Cumulative Review. And once I got the circle and graph | {
"domain": "snionline.it",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9770226260757066,
"lm_q1q2_score": 0.818373664150042,
"lm_q2_score": 0.8376199714402813,
"openwebmath_perplexity": 897.3256986854708,
"openwebmath_score": 0.5953616499900818,
"tags": null,
"url": "http://snionline.it/kfvh/rotating-ellipse-desmos.html"
} |
electric-circuits, conservation-laws, electric-current, electrical-resistance
It is just like the electrons which have reached the end of the first resistor communicate the presence of the resistor to the electrons coming behind them and convey them that they have to come slowly because there is a resistor ahead.
Griffith explains this very efficiently. Also there a certain beautiful answers here concerning these questionS ! | {
"domain": "physics.stackexchange",
"id": 37720,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "electric-circuits, conservation-laws, electric-current, electrical-resistance",
"url": null
} |
catkin, rosbuild
Originally posted by Dirk Thomas with karma: 16276 on 2013-09-17
This answer was ACCEPTED on the original site
Post score: 4
Original comments
Comment by Johannes Meyer on 2013-09-17:
@Dirk We are working with a mixed catkin/rosbuild source space without problems. The ROS_PACKAGE_PATH is not an issue as catkin will add the src folder, not the devel folder. You won't even need a rosbuild workspace initialized with rosws then.
Comment by Dirk Thomas on 2013-09-17:
Thanks, you are right. I will update my answer to not contain false information.
Comment by Markus Achtelik on 2013-09-17:
Thanks a lot for the answers and suggestions! I wasn't fully aware of the different folders to check-out to with one rosinstall file. Since indeed multiple people will have to use this setup, that (and probably vcstool) seems to be the best solution for now. | {
"domain": "robotics.stackexchange",
"id": 15543,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "catkin, rosbuild",
"url": null
} |
refraction
Title: What does 'relative' mean when we talk about refractive index? What does it mean to say, "the refractive index of medium $B$ relative to medium $A$"? Assume that in this case, medium $A$ is optically denser than medium $B$.
I have difficulties trying to understand the word 'relative' in aforementioned quote. Does it mean refractive index of $A$ divided by the refractive index of $B$ or the other way round? The fundamental thing about a refractive index is that it measures the speed of electromagnetic propagation in the medium in question. It is the ratio of the speed of light in the vacuum to that in the medium. Its a scale factor that measures the speed of the light in the medium to that in a vacuum. | {
"domain": "physics.stackexchange",
"id": 38516,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "refraction",
"url": null
} |
sorting, vba, excel, collections
' find bottom of batch
Dim Rng As Range
If Trim(ToFind) <> "" Then
With Sheets("Collar (Top View)").Range("I2:I30000")
Set Rng = .Find(What:=ToFind, _
after:=.Cells(.Cells.Count), _
LookIn:=xlValues, _
LookAt:=xlWhole, _
SearchOrder:=xlByRows, _
searchdirection:=xlPrevious, _
MatchCase:=False)
If Not Rng Is Nothing Then
outEndIndex = Rng.Row ' found bottom
Else
MsgBox "Nothing found"
Exit Function
End If
End With
End If
' Loop past remeasures
outStartIndex = outEndIndex
Do While (Cells(outStartIndex, 11) = 1)
outStartIndex = outStartIndex - 1
Loop | {
"domain": "codereview.stackexchange",
"id": 11741,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "sorting, vba, excel, collections",
"url": null
} |
modeled as a graph comprising N nodes connected by M edges. Shortest Path (Unweighted Graph) Goal: find the shortest route to go from one node to another in a graph. The Edge can have weight or cost associate with it. single source–single destination (also called s−t): given a graph and two nodes s and t, find an optimal path from s to t, 2. Input to the algorithm is a graph G (N,L) with nonnegative edge weights and a starting vertex u. A graph with 6 vertices and 7 edges In graph theory, the shortest path problem is the problem of finding a path between two vertices (or nodes) in a graph such that the sum of the weights of its constituent edges is minimized. 23 • Nodes that occur on many shortest paths between other nodes in. A directed graph or digraph is a graph D = (V,A) where each edge has a direction. If we want to find the shortest weighted path (in this case, distance. Three different algorithms are discussed below depending on the use-case. The starting node is called the | {
"domain": "incommunity.it",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9811668679067631,
"lm_q1q2_score": 0.8021769968098277,
"lm_q2_score": 0.8175744850834648,
"openwebmath_perplexity": 387.29434216764923,
"openwebmath_score": 0.565926730632782,
"tags": null,
"url": "http://incommunity.it/qhie/shortest-path-between-two-nodes-in-a-weighted-graph.html"
} |
quantization, digital-to-analog
If you can follow my logic up to this point I have one additional question because in my tests changing the phase of my sampled analog wave doesn't seem to change the frequencies of the quantization error like I thought it would. Am I making a mistake in my test?
For the last week or so I have been trying to understand how quantization error results in the noise floor outside of a mathematical perspective and I haven't really had any luck finding a source that discussed quantization noise without using equations to show where quantization error comes from. | {
"domain": "dsp.stackexchange",
"id": 2519,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "quantization, digital-to-analog",
"url": null
} |
slam, navigation, mapping, hector-slam, hector-mapping
Originally posted by TJump on ROS Answers with karma: 160 on 2012-08-11
Post score: 1
The answer by jodafo sums up things pretty well. To add just a minor point: The mapping_default.launch file is an example launch file and has some parameters specified using the <arg> tag to facilitate reuse. If your robot for example uses 'my_base_frame' as a base_frame and 'odom' as odom frame you can use the mapping_default.launch file like so in your launch file:
<include file="$(find hector_mapping)/launch/mapping_default.launch">
<arg name="base_frame" value="my_base_frame"/>
<arg name="odom_frame" value="odom"/>
</include>
Of course, this is just optional. You can write your own launch file or specify parameters using a shorter form like here.
Originally posted by Stefan Kohlbrecher with karma: 24361 on 2012-08-13
This answer was ACCEPTED on the original site
Post score: 4
Original comments
Comment by jondo on 2015-05-22:
Can you please update the broken Google Code links? | {
"domain": "robotics.stackexchange",
"id": 10572,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "slam, navigation, mapping, hector-slam, hector-mapping",
"url": null
} |
navigation, costmap
[ WARN] [1406897188.727111389]: Rotate recovery behavior started.
[ERROR] [1406897188.727278521]: Rotate recovery can't rotate in place because there is a potential collision. Cost: -1.00
[ERROR] [1406897189.489224920]: Aborting because a valid control could not be found. Even after executing all recovery behaviors | {
"domain": "robotics.stackexchange",
"id": 18856,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "navigation, costmap",
"url": null
} |
electrostatics, electric-fields, gauss-law
Title: Gaussian surface without any charge inside it Suppose a Gaussian surface has no net charge inside it. Does it mean that the electric field $E$ is necessarily zero at all points on the surface? And is the converse also true? Can this be shown mathematically? No it is not necessarily 0.
You can think about Gauss Law this way: It relates the total flux of the eletrical field to the net charge inside the surface, it is a direct relation between eletrical flux and charge inside. The flux is necessary 0, not the eletric field.
Picture a point charge and a gaussian surface beside it ( but not with it inside ), the field is clearly not 0 at all points of the surface but the flux is. | {
"domain": "physics.stackexchange",
"id": 42013,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "electrostatics, electric-fields, gauss-law",
"url": null
} |
quantum-mechanics, classical-mechanics, moment-of-inertia, rigid-body-dynamics, stability
The problem has indeed been studied in nuclear and molecular physics. A nice discussion can be found in Sect 4.5 of volume II of Bohr & Motelson, Nuclear Structure.
At low excitation energy there is no remnant of the intermediate axis theorem. The spectrum is discrete, and the states can only be labeled by discrete symmetries (there is no continuous symmetry, we cannot simultaneously diagonalize any $L_i$ and $H$, and there is no sense in which the system is spinning around a fixed axis). | {
"domain": "physics.stackexchange",
"id": 71669,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "quantum-mechanics, classical-mechanics, moment-of-inertia, rigid-body-dynamics, stability",
"url": null
} |
arduino, current
The 5V that connects to Vcc and powers your chip comes from one of two places. Either the USB connection, which in most cases is limited to supplying 500mA. Or an external power supply (wall wort or otherwise) which can supply as much current as is labeled on package.
Vin is your external power supply if connected. USBVCC is your USB power if connected. +5V is whichever has a higher voltage.
You seem to be interested in using an external power supply to run your Arduino and a motor. No problem. You just need to branch off of Vin before the regulator that turns Vin into +5V and powers your chip.
Have a look at this Motor Shield tutorial by Adafruit. In the below diagram, they are powering a motor off of a +9V Vin. In this diagram they are branching off before IC1 which is a 78L05Z. On your Duemilanove, this should be IC4, an MC33269. | {
"domain": "robotics.stackexchange",
"id": 59,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "arduino, current",
"url": null
} |
Then try this function $$f(x)=4x(x+1)$$:
Code:
LBL B RCL 1 1 + RCL 1 × 4 × RTN
Examples:
-0.5
ENTER
0.5
A
9.999999 99
-0.5
ENTER
A
9.999999 99
0.5
ENTER
A
9.999999 99
Even initial guesses very close to the solutions lead to the same result:
-1.00001
ENTER
-0.99999
A
9.999999 99
-0.00001
ENTER
0.00001
A
9.999999 99
Cheers
Thomas
02-18-2019, 03:49 AM
Post: #15
Gamo Senior Member Posts: 518 Joined: Dec 2016
RE: Small Solver Program
Your're right that only work for certain situations.
Gamo
02-18-2019, 05:20 AM
Post: #16
Thomas Klemm Senior Member Posts: 1,448 Joined: Dec 2013
RE: Small Solver Program
If you compare your algorithm with Newton's method:
$$x_{n+1}=x_{n}-\frac {f(x_{n})}{f'(x_{n})}$$
you may notice that the number in register 0 should in fact be $$f'(x_{n})$$ or at least a good approximation thereof.
And with this in mind indeed the solution can now be found:
$$f'(x) = \frac{d}{dx}4 x (x + 1) = 8 x + 4$$
$$f'(-1) = -4$$
$$f'(0) = 4$$
Examples: | {
"domain": "hpmuseum.org",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9752018426872776,
"lm_q1q2_score": 0.8652035633588538,
"lm_q2_score": 0.8872046026642944,
"openwebmath_perplexity": 2839.9652737837514,
"openwebmath_score": 0.3751296401023865,
"tags": null,
"url": "https://www.hpmuseum.org/forum/thread-12423.html"
} |
Number of solutions of $e^x=x^3$
How can I analytically obtain the number of solutions of the equation $$e^x=x^3$$?
I know Lambert's $$W$$ function, but even using that, we need to know the value of $$W(-1/3)$$ which I think we cannot calculate without a calculator/graph/etc.
I do not need the exact solutions of the equation, I just need to know the number of solutions it has. Is there any good approximation?
I tried using a method of comparing slopes of the two functions on the L.H.S and R.H.S , but it was turning out to be too lengthy.
• Are you asking for the specific solutions for this problem or a general method? – Ryan Shesler Apr 28 at 13:34
• @DavidMitra A typo by me. I should have said Clearly there are no negative solutions. You should also know $0^3 \lt e^0$ and $3^3 \gt e^3$ and $16^3 = 2^{12} \lt e^{16}$, so by continuity there should be at least two solutions. Now look at derivatives to show there are exactly two – Henry Apr 28 at 13:44 | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9719924777713888,
"lm_q1q2_score": 0.8120837173479978,
"lm_q2_score": 0.8354835411997897,
"openwebmath_perplexity": 175.0117051280662,
"openwebmath_score": 0.9381097555160522,
"tags": null,
"url": "https://math.stackexchange.com/questions/3205582/number-of-solutions-of-ex-x3"
} |
and Position Vectors. A force is a vector quantity which means that it has both a magnitude and a direction associated with it. Use our free online resultant vector calculator using parallelogram law of forces to calculate the magnitude and direction of the resultant vector for the given magnitude and angle of vectors. Finding resultant force using Component Method 1. Angle between two vectors a and b can be found using the following formula: Library: angle between two vectors. (Chapter 2) Two forces act on the hook. The diagonal of the parallelogram PBCA is the resultant force R, which forms two scalene triangles with the forces F 1 and F 2. Find the anlge between the two forces, rounded to the nearest degree. For example, they are used to calculate the work done by a force acting on an object. The direction of the moment is through the point and. Sk „^ ^ (-3-0)i + (-6-0)j+(0-6)b Jc-3 - 0. Two forces with magnitudes of 20 pounds and 14 pounds and an angle of 55° between them are | {
"domain": "aranceinn.it",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.979667647844603,
"lm_q1q2_score": 0.8076986803761943,
"lm_q2_score": 0.8244619306896956,
"openwebmath_perplexity": 431.3631302469679,
"openwebmath_score": 0.642760157585144,
"tags": null,
"url": "http://aranceinn.it/lhkt/determine-the-magnitude-of-the-resultant-force-3d.html"
} |
matlab, convolution, lowpass-filter
Now y should have nearly no frequencies above 500, right?
If I check the signal there doesn't seem have happened a lowpass filtering. It appears you're getting a bit lost between the time and frequency domains. If "Num" is the numerator of an FIR filter (as it appears), these are the coefficients (or impulse response) of your filter. The impulse response as a signal exists in the time domain.
If you want to perform a filtering operation using this impulse response (or filter kernel as some call it), you should perform a convolution (conv) between it and the signal you wish to filter in the time domain.
--
The impulse response you've created has an equivalent frequency domain response (which you will have seen in fdatool). The time domain convolution described above is equivalent to multiplying this frequency-domain response by the frequency-domain representation of your input signal. | {
"domain": "dsp.stackexchange",
"id": 1114,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "matlab, convolution, lowpass-filter",
"url": null
} |
python, performance, algorithm, programming-challenge
Output
For each test case, display satisfiable on a single line if there is a satisfiable assignment; otherwise display unsatisfiable.
Sample Input
2
3 3
X1 v X2
~X1
~X2 v X3
3 5
X1 v X2 v X3
X1 v ~X2
X2 v ~X3
X3 v ~X1
~X1 v ~X2 v ~X3 | {
"domain": "codereview.stackexchange",
"id": 39675,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "python, performance, algorithm, programming-challenge",
"url": null
} |
x 3 matrix (using cofactor matrix) •Calculating the inverse of a 3×3matrix is: •Compute the matrix of minors for A. - The successive elements are obtained by adding N to the current element. In other words, for bytes A-P, I'm looking for the most efficient (in Each row of my matrix can fit into a 32-bit integer, and I'm looking for answers that can perform a transpose quickly using general purpose hardware. Matrix of Cofactors. The transpose of a transpose is the initial matrix. vtkMatrix4x4 is a class to represent and manipulate 4x4 matrices. This calculator solves system of four equations with four unknowns. The inverse matrix has the property that it is equal to the product of the reciprocal of the determinant and the adjugate matrix. However, matrix multiplication does not change (it is still Arow dot. If most of your matrices are used as transform matrices, because of their special property, we have a fast route for calculating their inverse. To obtain it, we interchange rows and | {
"domain": "maboan.de",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9777138105645058,
"lm_q1q2_score": 0.821019501314712,
"lm_q2_score": 0.8397339716830606,
"openwebmath_perplexity": 530.073518005604,
"openwebmath_score": 0.5283272862434387,
"tags": null,
"url": "http://maboan.de/transpose-matrix-4x4.html"
} |
performance, haskell, statistics
Why are you using foldl1'? It makes sense to use foldl' from a performance perspective, but it isn't clear to me why you require a nonempty list. Perhaps use a Maybe to encapsulate this possibility of failure, or outline why you expect a nonempty list in a comment. It's a good idea to keep tabs on where your partial functions are to avoid surprises at runtime. My function just returns 0 for a null Foldable.
Your types can be generalized more than Int and Double, if you want this to be more flexible/reusable. What I did to find these types was track down what functions you were using and figure out what their types were (which were more general than Int or Double or []). Then I resolved the overall function to its most general type. Whether this is necessary or useful depends on your application. I think the most useful generalization here is to Foldable in case you wanted to calculate entropy of things that were not lists. | {
"domain": "codereview.stackexchange",
"id": 34735,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "performance, haskell, statistics",
"url": null
} |
self-driving cars and many more are just a few examples. What is the distribution of the sum? 30. , in short (H, H) or (H, T) or (T, T) respectively; where H is denoted for head and 1. Two fair dice are rolled and the sum of the points is noted. Chances and probability What is an event? The interest charged the third year is the interest rate, times the sum of the loan and the first two years' interest amounts. Note that a 2-element event {1, 2} has the probability of 1/3 = 2·1/6, whereas a 3-element event {4, 5, 6} has the probability of 1/2 = 3·1/6. To find the probability we use the mutually exclusive probability formula P(A) + P(B). There are 3 ways to get a sum of 4 on 2 dice. Sample space S = {H,T} and n(s) = 2. The sample space S is given by S = {1,2,3,4,5,6}. A card from a pack of 5 2 cards is lost. Let B be the event - The sum of the top faces of the 3 dice >= 5. That is a total of 12 ways to roll a sum divisible by 3, and if there are 36 possible rolls, the probability is 12 | {
"domain": "salesianipinerolo.it",
"id": null,
"lm_label": "1. Yes\n2. Yes",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9766692339078751,
"lm_q1q2_score": 0.846807163041299,
"lm_q2_score": 0.8670357718273068,
"openwebmath_perplexity": 260.607987939569,
"openwebmath_score": 0.6550420522689819,
"tags": null,
"url": "http://salesianipinerolo.it/asmz/when-two-dice-are-rolled-find-the-probability-of-getting-a-sum-of-5-or-6.html"
} |
gravitational-waves
Title: Where can I watch the announcement from LIGO about gravitational waves? Today the LIGO consortium are having a press conference to update us on their search for gravitational waves. How should I watch the announcement? The event will be live streamed on youtube here: https://www.youtube.com/user/VideosatNSF/live
The will also be tweeting: https://twitter.com/ligo
A video of the conference will also be available afterwards if you miss it. It starts at 10:30 EST, which is 3:30 GMT. | {
"domain": "astronomy.stackexchange",
"id": 1377,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "gravitational-waves",
"url": null
} |
quantum-field-theory, mathematics
Title: Where does this equation originate from? (found in the Big Bang Theory) Recently, I've been watching "The Big Bang Theory" again and as some of you might know, it's a series with a lot of scientific jokes in it - mostly about Physics or Mathematics. I understand most of the things mentioned in the series and whenever I don't understand a joke, I just look up the knowledge I'm missing on wikipedia - e.g. I learnt about Schrödinger's cat in this way.
However, at one point, I did not know how to proceed, which is why I'm asking this question. At a Physics quiz, the participants are asked to "solve" the following equation: | {
"domain": "physics.stackexchange",
"id": 1200,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "quantum-field-theory, mathematics",
"url": null
} |
solid itself, see e.g the... Regel mit Microsoft 365 installiert as a sum-class Symbol with the \limit command Equation Tools, on the Design,... Triple integrals this is most useful for double surface integral symbol triple integrals =1 a ( ; z ) ¢¢! surface. In Faraday 's law, do the following: in surface integral symbol opposite direction, we would get very... U222F, u=222F or c+222F, x ] can be entered as int or \ [ ]. Flux of a surface in 3-space Math Symbol Smiley Face U+222F can do get... | {
"domain": "skudeneshavnarena.no",
"id": null,
"lm_label": "1. Yes\n2. Yes\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9511422213778251,
"lm_q1q2_score": 0.8006959104780056,
"lm_q2_score": 0.8418256412990658,
"openwebmath_perplexity": 2982.2442856207877,
"openwebmath_score": 0.8856879472732544,
"tags": null,
"url": "https://skudeneshavnarena.no/f3j50gtc/e17965-surface-integral-symbol"
} |
gravitational-lensing
Title: Given that gravity bends the path of light, how confident can we be that galaxies are where they seem to be? The widely known phenomenon termed gravitational lensing is believed to curve space, thereby affecting the path followed by light and other electromagnetic waves.
This effect is associated principally with galaxies and galaxy clusters, as it requires considerable mass. But in theory any star or star cluster, or black hole, can have this effect to some degree.
What can we tell for sure about the position of external galaxies, if we are uncertain that their light is actually coming to us along a straight path: i.e. if light follows the curvature of space, and that curvature is not uniform, how can we be sure we are not observing, for example, the light from a single source appearing to us as more than one object.
Can a galaxy appear to be in more than one place in the sky?
The widely known phenomenon termed gravitational lensing is believed | {
"domain": "astronomy.stackexchange",
"id": 2070,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "gravitational-lensing",
"url": null
} |
python, pygame, performance
go=1
else:
gotime-=1
pygame.display.update()
elif ingame==0:
blocklist=[]
mse = pygame.mouse.get_pos()
player=[]
key = pygame.key.get_pressed()
text=font.render(splash, True, (255,255,255))
if key[K_RETURN]:
ingame=1
for event in pygame.event.get():
if event.type == QUIT:
exit()
if event.type == KEYDOWN:
print event.key
if sbtnrect.collidepoint(mse):
if pygame.mouse.get_pressed()==(1,0,0):
ingame='gen'
top=(random.randint(5,8)*32)
cen=(top+random.randint(4,6)*32)
down=15
across=0 | {
"domain": "codereview.stackexchange",
"id": 4717,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "python, pygame, performance",
"url": null
} |
ros, ros-kinetic, topic, publisher, messages
from random import randint
from random import uniform
from collections import OrderedDict
from std_msgs.msg import String
from my_pkg.msg import AnchorScan
class CalcPos2D3AIte:
def __init__(self, SX, SY, SZ, AX, AY, AZ, BX, BY, BZ, TZ, das, dbs):
## DO STUFF
## DO STUFF
## DO STUFF
pre_TY = (N2 -(M21*N1/M11))/(M22-(M21*M12/M11))
pre_TX = ((-1*M21*N1/M11) + (M21*M12/M11)*pre_TY)/(-1*M21)
TX = pre_TX
TY = pre_TY
self.TX_cm = int(TX*100)
self.TY_cm = int(TY*100)
self.TZ_cm = int(TZ*100)
def position_pub_sub():
rospy.init_node('test2_positioning_node', anonymous=True)
rospy.Subscriber('selectedAnchors', AnchorScan, callback)
pub = rospy.Publisher('position', AnchorScan, queue_size=2)
rate = rospy.Rate(10)
while not rospy.is_shutdown():
if var_control: | {
"domain": "robotics.stackexchange",
"id": 32852,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "ros, ros-kinetic, topic, publisher, messages",
"url": null
} |
# Math Help - Find the area bounded by...
1. ## Find the area bounded by...
Find the area bounded by,
$(x^{2}+y^{2})^{3} = 4a^{2}x^{2}y^{2}$
I'm a little confused by the question itself. What are they talking about? Is it a surface? It it simply something in the x-y plane? How do I get this one started?
Thanks again!
2. Originally Posted by jegues
Find the area bounded by,
$(x^{2}+y^{2})^{3} = 4a^{2}x^{2}y^{2}$
I'm a little confused by the question itself. What are they talking about? Is it a surface? It it simply something in the x-y plane? How do I get this one started?
Thanks again!
Use the polar coordinates
$\displaystyle{(x^2+y^2)^3=4a^2x^2y^2}$
$\displaystyle{x=\rho\cos\varphi,~y=\rho\sin\varphi }$
$\displaystyle{\rho^6=4a^2\rho^4\cos^2\varphi\sin^2 \varphi}$
$\displaystyle{\rho^2=4a^2\cos^2\varphi\sin^2\varph i}$
$\displaystyle{\rho^2=a^2\sin^22\varphi}$ | {
"domain": "mathhelpforum.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9579122720843812,
"lm_q1q2_score": 0.8103386458952844,
"lm_q2_score": 0.8459424411924673,
"openwebmath_perplexity": 711.2813003817886,
"openwebmath_score": 0.9326744675636292,
"tags": null,
"url": "http://mathhelpforum.com/calculus/164485-find-area-bounded.html"
} |
inorganic-chemistry, acid-base
However, it cannot be used to explain acidity in non-aqueous media, where a Brønsted–Lowry definition of an acid comes in handy: the acid is a proton donor.
This can be illustrated by the reaction with liquid ammonia:
$$\ce{H2S(g) + 2 NH3(l) ->[\pu{-40 °C}] (NH4)2S(s)}$$
References | {
"domain": "chemistry.stackexchange",
"id": 12759,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "inorganic-chemistry, acid-base",
"url": null
} |
organic-chemistry, acid-base
Cation solvation: The difference in the stability of the conjugate acid of the solvent may be the factor that causes the difference between water and methanol. The $\mathrm{pK_a}$ of $\ce{CH3OH2+}$ is approximately -2.5 (several sources, none giving exact answers) and the $\mathrm{pK_a}$ of $\ce{H3O+}$ is -1.7. Therefore protonated methanol is less stable than protonated water and so this disfavours dissociation of the acid in methanol. This page claims that this can be attributed to oxygen $p$-orbital donation into $\ce{C-H}~\sigma^*$ orbitals but I don't have enough knowledge of MO theory to verify this (maybe someone else can).
Overall the greater acidity of ethanoic acid in water than methanol seems to be down to the greater dielectric constant of water and the greater stability of the solvent cation formed.
This page says some good things about the subject (some of my ideas were developed from reading this). | {
"domain": "chemistry.stackexchange",
"id": 3478,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "organic-chemistry, acid-base",
"url": null
} |
c++, embedded
int m_systemLatencyMedian = 0;
int m_systemLatencyMedianEVR = 0;
int m_systemLatencyMax = 0;
int m_systemLatencyMin = 0;
int m_systemLatencyMaxEVR = 0;
int m_systemLatencyMinEVR = 0;
}SYSLAT_DATA; | {
"domain": "codereview.stackexchange",
"id": 40653,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c++, embedded",
"url": null
} |
algorithms
Input: order $N$, points $A_0,\ldots,A_N$, time $t \in (0,1)$.
Calculate $\overline{A_i A_{i+1}} = A_i(1-t) + A_{i+1}t$ for $0 \leq i \leq N-1$.
Calculate $\overline{A_i A_{i+1} A_{i+2}} = \overline{A_i A_{i+1}} (1-t) + \overline{A_{i+1} A_{i+2}} t$ for $0 \leq i \leq N-2$.
Continue similarly for $N-2$ more steps.
Output $\overline{A_0 A_1 \ldots A_n}$.
It is not completely clear what it does it mean to "implement" De Casteljau's algorithm. However, a reasonable informal interpretation of this statement is as follows:
Schedule the computations in De Casteljau's algorithm in a way that uses the least amount of space and the least amount of computations. | {
"domain": "cs.stackexchange",
"id": 20826,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "algorithms",
"url": null
} |
c, reinventing-the-wheel
*result = (int) parsed;
for (chrs_read = 0; str != end; str++)
chrs_read++;
return chrs_read;
}
/*
* e_print_field_width: pads the output according to "data" and "length" and
* returns the number of characters printed, or "E_PRINT_ERROR" on error.
* "length" must the length of output except for padding.
*/
static int e_print_field_width(struct e_print_data *data, int length)
{
int chrs_printed = 0;
char chr;
assert(data != NULL && length >= 0);
if (length >= data->fmt.field_width)
return 0;
chr = data->fmt.flag.zero_pad ? '0' : ' ';
for (length = data->fmt.field_width - length; length > 0; length--) {
if (e_emit_char(data, chr) == E_PRINT_ERROR)
return E_PRINT_ERROR;
chrs_printed++;
}
return chrs_printed;
} | {
"domain": "codereview.stackexchange",
"id": 37971,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c, reinventing-the-wheel",
"url": null
} |
we can take the concepts here and use them in a wide variety of useful situations. Least squares optimization. The MATLAB/BARON interface is provided by The Optimization Firm. To interface BARON with MATLAB, you must download both BARON and the MATLAB/BARON interface zip archive. The interface is provided free of charge and with no warranties. types to pass SOS constraints to Gurobi. What Is the Optimization Toolbox? The Optimization Toolbox is a collection of functions that extend the capability of the MATLAB® numeric computing environment. On the international level this presentation has been inspired from (Bryson & Ho 1975), (Lewis 1986b), (Lewis 1992), (Bertsekas 1995) and (Bryson 1999). ) and facility locations are solved using the MATLAB code given in the appendix with special emphasis given to facility location problems. Nonlinear Programming (NLP) based on Optimization Techniques Nonlinear programming (also called NLP , for short) is the method or process of solving a system of | {
"domain": "thebrandcg.com",
"id": null,
"lm_label": "1. YES\n2. YES\n\n",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9728307653134904,
"lm_q1q2_score": 0.8106837997850292,
"lm_q2_score": 0.8333245911726382,
"openwebmath_perplexity": 1227.99381299854,
"openwebmath_score": 0.3481185734272003,
"tags": null,
"url": "http://thebrandcg.com/4bmt/vikrw.php?bfi=matlab-optimization-examples"
} |
c#, linq
is at least as easy to read as your LINQ expression,
does not require the explicit Cast<...>(),
does not require ToList().
If you put it on one line, it is actually shorter than your LINQ-based solution.
foreach(DataGridViewRow row in dGV_factory.Rows)
{
//Replace every null cells with an empty string
foreach (DataGridViewCell cell in row.Cells) cell.Value = cell.Value ?? "";
}
Although, for readability, I'd prefer:
foreach (DataGridViewRow row in dGV_factory.Rows)
{
foreach (DataGridViewCell cell in row.Cells)
{
cell.Value = cell.Value ?? "";
}
}
(Of course, this is still a great improvement over your co-worker's code.) | {
"domain": "codereview.stackexchange",
"id": 4524,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c#, linq",
"url": null
} |
multithreading, swift, grand-central-dispatch
Second, even if it’s only a couple of times per second, you might want to avoid starting and stopping the activity indicator too quickly (because it yields a spinner that is constantly restarting, yielding a “Max Headroom” style of stuttering effect). For example, if active changes every ¼ second, and keeps doing that for 10 seconds, you may want to just want to keep the spinner going for that full 10 seconds, not starting and stopping it repeatedly. You can accomplish this by programming some latency in the “stop activity indicator” routine. E.g. when active is set to false, add non-repeating timer to stop the activity indicator in ½ second, but only after canceling any prior timer, if any. Likewise, when active is set to true, only “start” the activity indicator if you know it’s not already started. | {
"domain": "codereview.stackexchange",
"id": 36095,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "multithreading, swift, grand-central-dispatch",
"url": null
} |
algorithms, complexity-theory, graphs, algorithm-analysis
You have got the basic idea. However, a new cycle might not be found when a vertex points back to a vertex that has been traversed, even if it is not part of any confirmed cycles. For example, consider the moment when your algorithm have visited 0, 5, 2, 3, 10, 2, 1, 12 and then 5 again. Vertex 5, although revisited, is not part of any cycle.
To ensure that a new cycle will be found when you revisited a vertex, the first visit to that revisited vertex must happen after the visit to the vertex i in your algorithm. That is why the variable $round$ is introduced in the above algorithm, which is, in fact, the only critical difference between the two algorithms.
Exercises
Here are a couple of exercises that help prove the above algorithm is correct.
Exercise 1. Show that there is exactly one cycle in each connected component.
Exercise 2. Prove the following invariant of the above algorithm. At the start of step 3.1, all visited vertices and edges so far form a unique-outgoing graph. | {
"domain": "cs.stackexchange",
"id": 15419,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "algorithms, complexity-theory, graphs, algorithm-analysis",
"url": null
} |
homework-and-exercises, energy, momentum, spring
I think I can't follow this second energy approach, because I guess I must use rotational kinetic energy. But using rotational kinetic energy is not within the scope of the study.
Only Conservation of Energy and Momentum ideas are to be used.
I am just wondering if I am correct with the first approach and if
there is a way to do this via Energy-Momentum ideas.
Hope someone can help.
Regards. Well I would say your first approach is absolutely correct and will result in right answer if the calculations are done correctly (I have not done the calculations) but your second approach is faulty.
Problem with second approach
In the second approach you have used the conservation of mechanical energy it seems. The problem is that conserving mechanical energy would mean that the kinetic energy loss is equal to the potential energy gain or vice versa but that isn't the case. Here both have increased due to some force which would have set the mass in motion.
Possible Energy method approach | {
"domain": "physics.stackexchange",
"id": 27645,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "homework-and-exercises, energy, momentum, spring",
"url": null
} |
java
// bubble sort to sort by number of ratings with averages still in order
for(int i = average.length - 1; i >= 0; i--) {
for(int j = 0; j <= i - 1; j++) {
if(average[j][0] == average[j + 1][0] && unsorted[(int)average[j][1]][1] < unsorted[(int)average[j + 1][1]][1]) {
TEMP = average[j][1];
average[j][1] = average[j + 1][1];
average[j + 1][1] = TEMP;
}
}
}
String[][] sorted = new String[moviesRows][3];
for(int i = 0; i < moviesRows; i++) {
sorted[i][0] = String.valueOf(average[i][0]); // average rating
sorted[i][1] = String.valueOf(unsorted[(int)average[i][1]][1]); // number of ratings
sorted[i][2] = movies[(int)average[i][1]][1]; // movie name
} | {
"domain": "codereview.stackexchange",
"id": 10733,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "java",
"url": null
} |
homework-and-exercises, lagrangian-formalism, constrained-dynamics
My work so far:
I want to use 2 generalized coordinates to describe my system: $x$, the location of the center of the ring along the flat plane and $\theta$, the angle that the rod inside the cylinder makes with respect to the flat plane (I define increasing $\theta$ as counterclockwise).
Kinetic Energy: $\frac{1}{2} m \dot{x}^{2} + \frac{1}{2} m \frac{R^2}{4}\dot{\theta}^{2}$
Potential Energy: $mg(\frac{R}{2}\sin{\theta} + R)$
There is also a contraint due to the no slipping of the form:
$f(x,\theta) = x + R\theta = 0$
With this, my Lagrangian is:
$L = \frac{1}{2} m \dot{x}^{2} + \frac{1}{2} m \frac{R^2}{4}\dot{\theta}^{2} - mg(\frac{R}{2}\sin{\theta} + R)$
The Euler Lagrange equations with the holonomic constraint are:
$\frac{d}{dt}\frac{\partial L}{\partial \dot{x}} - \frac{\partial L}{\partial x} - \lambda\frac{\partial f}{\partial x} = 0$
$\frac{d}{dt}\frac{\partial L}{\partial \dot{\theta}} - \frac{\partial L}{\partial \theta} - \lambda\frac{\partial f}{\partial \theta} = 0$ | {
"domain": "physics.stackexchange",
"id": 52445,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "homework-and-exercises, lagrangian-formalism, constrained-dynamics",
"url": null
} |
us to define symbolic variables and then work with them. Contribute to sympy/sympy development by creating an account on GitHub. Espansione di serie SymPy can compute asymptotic series expansions of functions around a point. If None (default), use spacing dx between consecutive elements in y. Solve polynomial and transcendental equations. If you want the numerical value as an answer, why not use scipy. Here, we see how to solve and represent definite integrals with python. Using the doit() method in simpy module, we can evaluate objects that are not evaluated by default like limits, integrals, sums and products. I think I have. Perform basic calculus tasks (limits, differentiation and integration) with symbolic expressions. This algorithm is much faster, but may fail to find an antiderivative, although it is still very powerful. For instance, for evaluating the Hessian of x'Ax MC is a factor of 100 faster than TF. For example, to compute. By default, 15 digits of precision are used, To | {
"domain": "yiey.pw",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9748211590308922,
"lm_q1q2_score": 0.8058961451185194,
"lm_q2_score": 0.8267117898012105,
"openwebmath_perplexity": 1338.5135338409063,
"openwebmath_score": 0.7079145312309265,
"tags": null,
"url": "http://sgix.yiey.pw/sympy-evaluate-integral.html"
} |
relative-motion
What implication does this result have on constant velocity motion? Well it implies that constant velocity is relative since:
-every observer can claim he's at rest and it's the other observer who's moving.
-since the laws of physics are the same in both the rest and the moving(with constant velocity) frame. If you locked both $S$ and $S'$ in a closed box, they won't be able to make an experiment to tell apart if they're moving or not. The world just behaves the same if you're at rest or moving with constant velocity.
What about motion that's not at constant velocity?
It turns out that such frames are non-inertial frames of reference, in that the laws of physics don't hold true in them. | {
"domain": "physics.stackexchange",
"id": 24333,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "relative-motion",
"url": null
} |
string-theory, experimental-physics
By experimentally proving that the world doesn't contain gravity, fermions, or isn't described by quantum field theories at low energies; or that the general postulates of quantum mechanics don't work; string theory predicts that these approximations work and the postulates of quantum mechanics are exactly valid while the alternatives of string theory predict that nothing like the Standard Model etc. is possible
By experimentally showing that the real world contradicts some of the general features predicted by all string vacua which are not satisfied by the "Swampland" QFTs as explained by Cumrun Vafa; if we lived in the swampland, our world couldn't be described by anything inside the landscape of string theory; the generic predictions of string theory probably include the fact that gravity is the weakest force, moduli spaces have a finite volume and similar predictions that seem to be satisfied so far | {
"domain": "physics.stackexchange",
"id": 11859,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "string-theory, experimental-physics",
"url": null
} |
java, junit, base64
HMAC hmac = new HMAC(hashKey.getBytes(), hashMethod);
hmac.generateHash(str);
return hmac.getHash();
}
else
{
if (cl.hasOption("hash"))
{
log.error("No key given for HMAC.");
System.exit(-1);
}
if (cl.hasOption("key"))
{
log.error("No hashing algorithm given for HMAC.");
System.exit(-1);
}
}
return null;
}
/*
* @param str Perform Base operation
*/
public static byte[] doBase(byte[] bs) throws UnsupportedEncodingException
{
log.info("Input string for Base : " + bs); | {
"domain": "codereview.stackexchange",
"id": 11511,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "java, junit, base64",
"url": null
} |
It is isomorphic to the ring of matrices
$$\left\{\begin{bmatrix}a_1&a_3\\0&a_2\end{bmatrix}\,\middle|\,a_1, a_2,a_3\in \mathbb R\right\}$$
It's a semiprimary ring whose Jacobson radical is the subset with $a_1=a_2=0$. The Jacobson radical is nilpotent, and $R/J(R)\cong\mathbb R\times\mathbb R$. Here is a list of more properties of such a ring.
This sort of ring is fairly famous, and has nice interpretations. One of them is that if you select a chain of subspaces $\{0\}<V<W<\mathbb R\times \mathbb R$ ($W$ of dimension $1$, $V$ of dimension $2$) then the linear transformations of $\mathbb R\times\mathbb R$ which stabilize this chain is isomorphic to this triangular matrix ring. That is, $\phi$ stabiliezes the chain if $\phi(V)\subseteq\phi(W)$. | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9766692325496974,
"lm_q1q2_score": 0.8586355863518633,
"lm_q2_score": 0.8791467548438126,
"openwebmath_perplexity": 526.2422588281735,
"openwebmath_score": 0.979472815990448,
"tags": null,
"url": "https://math.stackexchange.com/questions/2557479/motivation-for-the-ring-product-rule-a-1-a-2-a-3-cdot-b-1-b-2-b-3-a/2557744"
} |
electromagnetism, electricity, applied-physics
Title: Magnetic flying engine I invented a flying engine moving entirely by magnetic forces (such as the force related with magnetic field of the Earth).
See http://porton.wordpress.com/2011/12/23/magnetic-vehicle/
The question is, can we build an engine of this type which is enough powerful to actually fly?
The question is both about the mechanical engine described in the post above and about a hypothetical (not developed by me in details) purely electronic version.
My question is: Describe operating characteristics of these kinds of engines. No such engine can exist--unless you custom-tailor your magnetic field.
Any such engine you build will need a current loop--since current requires a closed circuit to flow.
A current loop never has any force on it in a uniform magnetic field{*}. It can have a torque, so at max you can create a device that spins. | {
"domain": "physics.stackexchange",
"id": 14106,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "electromagnetism, electricity, applied-physics",
"url": null
} |
c++, performance, graphics, winapi
Remember that the Graphics class itself is a managed object and it will be garbage collected sooner or later. This class also uses unmanaged memory, the garbage collector doesn't "see" that memory and doesn't know that the actual memory used by the Graphics class may be much higher than the size of a Graphics instance. But fortunately you did it correctly: it's better to delete such objects as soon as you no longer need them, deleting will free any unmanaged memory or any other resources like opened files. | {
"domain": "codereview.stackexchange",
"id": 17168,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "c++, performance, graphics, winapi",
"url": null
} |
laser, laser-interaction, laser-cavity
The oscillator is the whole system. Optical resonator and gain medium.
This causes emitted photons to hit the gain medium, (The emitted photons from the pump, I'd assume ...
I'm not sure about the context, but usually we consider the pump energy to be coming in to the laser from somewhere else. From the point of view of the laser, pump photons would be absorbed (i.e., the opposite of emitted) in order to put the active species in its excited state. Probably they were emitted by some source somewhere, but that's not part of the laser proper.
Emitted photons likely refers to photons emitted by spontaneous emission in the gain medium.
if we tilt a resonator, the photons don't gain properly. This causes emitted photons to hit the gain medium, ... and then not oscillate back. | {
"domain": "physics.stackexchange",
"id": 40033,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "laser, laser-interaction, laser-cavity",
"url": null
} |
I usually hear it said "a field of characteristic $p$" with no plural. Also, $\mathbb C$ has characteristic 0 but can't be ordered, so that comment is kind of misleading. – Ben Millwood Jun 10 '12 at 17:40
@benmachine: Possible, I usually get confused about that. Feel free to edit, I am on the iPhone now... Also I mentioned that the complex numbers have char. zero but cannot be ordered. I don't know how that is misleading... – Asaf Karagila Jun 10 '12 at 17:50
@AsafKaragila: that doesn't sound like what you are saying, is all: you say "fields of characteristic 0 can be ordered ($\mathbb Q$ is, but $\mathbb C$ is not)" – I guess I thought it misleading because it's kind of ambiguous if you meant is/is not ordered, or is/is not characteristic 0. I guess I mentally inserted "all" before "fields", where you meant "only". – Ben Millwood Jun 10 '12 at 17:53 | {
"domain": "stackexchange.com",
"id": null,
"lm_label": "1. YES\n2. YES",
"lm_name": "Qwen/Qwen-72B",
"lm_q1_score": 0.9688561721629777,
"lm_q1q2_score": 0.8434835288334291,
"lm_q2_score": 0.8705972600147106,
"openwebmath_perplexity": 383.9475830903492,
"openwebmath_score": 0.8462031483650208,
"tags": null,
"url": "http://math.stackexchange.com/questions/156554/can-an-ordered-field-be-finite"
} |
neural-network, loss-function, mnist
Is it correct that training and validation loss are almost identical? Informal explanation:
We usually expect the validation loss to be higher than the training loss due to overfitting. This occurs because the model fits random noise in the training samples, it "memorizes" them.
However, to memorize the samples the model needs a sufficient capacity (lets say number of parameters), that allows it to memorize the samples.
In your example of a single-layer MLP, we have a very low model capacity, so we wouldn't expect overfitting to occur, which your experiments confirm.
If you're interested in a more rigorous explanation of this phenomenon, you should look into the "Bias-variance tradeoff". | {
"domain": "datascience.stackexchange",
"id": 11490,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "neural-network, loss-function, mnist",
"url": null
} |
ros, gazebo, force
Original comments
Comment by erpa on 2011-08-31:
Solved! To apply the force in the object reference frame first you have to get the pose of the object itself with GetWorldPose() and rotate the force vector accordingly ( i used RotateVector() ), last you can apply the force to the object. thanks again for help.
Comment by Martin Günther on 2011-08-30:
That could be true. I don't know if there's a better way, but perhaps you have to rotate the force vector yourself (grep for "rotate" in gazebo_plugins to see some examples).
Comment by erpa on 2011-08-30:
thanks, it's exactly what i was looking for! Just one last question, trying to run my simulation it appears that the force is applied using world reference frame instead then body frame, am i mistaken? I will also take a look at turtlebot_gazebo_plugins as soon as it finish the download :D
Comment by Martin Günther on 2011-08-30:
Okay, I've edited my answer to that effect.
Comment by erpa on 2011-08-30: | {
"domain": "robotics.stackexchange",
"id": 6545,
"lm_label": null,
"lm_name": null,
"lm_q1_score": null,
"lm_q1q2_score": null,
"lm_q2_score": null,
"openwebmath_perplexity": null,
"openwebmath_score": null,
"tags": "ros, gazebo, force",
"url": null
} |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.