All Questions

5
votes
3answers
241 views
5
votes
2answers
269 views

Is there something akin to “SubgraphIsomorphismQ” in Mathematica 9?

Provided two unlabeled graphs, $G$ and $H$, I would like to test where $H$ is a subgraph of $G$. In other words, I'd like to test whether we can prune some fixed number of vertices or edges from $G$ ...
5
votes
1answer
483 views

NestList and Euler's method

I am new to mathematica and so just experimenting with various programming constructs. Recently have been looking at NestList and how I could use this to implement ...
5
votes
3answers
721 views

Using PlotLegends

Please don't answer this with "Just trash PlotLegends" or anything like that as I have tried homebrew solutions. I keep running into problems which I can't debug as ...
5
votes
3answers
3k views

Summing along rows or columns of a matrix

I have a list of rows in database such as {{a,b,c}, {d,e,f},{g,h,i}} I want to be able to add each row across and each column down (like a spreadsheet). In other ...
5
votes
1answer
514 views

Simplistic Notation example

Notation package looks poorly documented. For example, GridBoxDividers option is not documented at all. Can someone give me a simplistic example of a Notation set ...
5
votes
1answer
290 views

How do I dynamically change Manipulate controls?

What I'd like to be able to do is dynamically change the axis of a 3D plot inside a manipulate. For example if I have a function that has three input variables I'd like a 3D plot using 2 of the ...
5
votes
2answers
2k views

Making mathematical animations with Mathematica

I recently stumbled upon the Cycloid and was working on finding its length and such when I found this animation on Wikipedia. Strikingly pretty and small in size too (66KB) So on searching how he ...
5
votes
1answer
644 views

Efficiently exporting many images as a video

I have many .gif images and I would like to export them as a single video file (I prefer .mov, but any video format is fine). But what if I have several tens of megabytes of .gif images? Is it ...
5
votes
2answers
2k views

How to use a matrix variable for a compiled function

I want to compile the following function which takes a matrix variable. ...
4
votes
0answers
41 views

Interpolation on an unstructured (mostly-structured) grid in 4D+

I frequently need to perform interpolations on an unstructured grid. Mostly, with the purpose of filling grid holes and then later continue with regular grid interpolations. Mathematica V9 and V10 ...
4
votes
4answers
337 views

Efficient method for Inserting arrays into arrays

This is strongly related to the following Questions: Looking for a way to insert multiple elements into multiple positions simultaneously in a list Building matrices by attaching vectors (columns) ...
4
votes
2answers
115 views

How to model shocks to parameter in a dynamic system?

My simple model is: m[t_] := m[t] = m[t - 1]*p + 2 m[0] = 0 p = 0.5 I can plot the system as: ...
4
votes
2answers
203 views

Sorting a large file

I have some huge logs, which are text files, containing up to a million rows each, and I need them sorted. Because trying to import one obviously makes Mathematica run out of memory, we must rule out ...
4
votes
4answers
508 views

Generate random points in a region with higher probability in a sub-region

I am trying to generate random samples of points in the unit square in such a way that points inside a given circle are twice as likely to be selected as points outside of that circle. I tried to ...
4
votes
1answer
298 views

Autoregressive distributed lag model

Could someone point me in the direction of creating an autoregressive distributed lag model in mathematica?
4
votes
2answers
339 views

Cannot call custom function loaded from script using C/C++ MathLink

I am using MathLink with C/C++ on a Unix system in order to call a Mathematica (version 9) function and get the result. The function I need to call is a personal function of mine ...
4
votes
1answer
454 views

How to solve this equation with integers as a solution?

I want to solve the equation $$x^y + y = y^x + x$$ with $x$, $y$ are integer numbers. I tried Solve[x^y + y == y^x + x, {x, y}, Integers] How to solve the ...
4
votes
1answer
274 views

How to force Pane to always scroll to end of content? [duplicate]

Mathematica seems to know about the actual end of content position in a Pane if given large enough (but not too large$^1$) initial position value. Here, the ...
4
votes
1answer
934 views

How do I find the best parameter to fit my data if the model is a interpolating function?

Hi I have a question regarding to find the best parameters for my model to fit my data. I have 3 ordinary equation, and I now just picked some parameters (...
4
votes
1answer
913 views

Visualize eigenvectors at specified points?

I am very new to Mathematica and I got stuck about visualizing eigenvectors 2D and 3D. I want to visualize my largest eigenvector field of tensor data(15x15). I wrote this code for instance : ...
4
votes
3answers
400 views

How to obtain a fixed number of solutions to $x+y=1$?

How to obtain a fixed number of solutions to $x+y=1$? For example, I want 4 solutions: $(1,0),(2,-1),(3,-2),(-2,3)$ I want to do this also on bigger equations such as $x+y+...=1$ and then I want to ...
3
votes
3answers
236 views

How can we plot the complex roots of an equation?

If we'd like to display the $n$ roots of a polynomial on the complex plane as points, how can we do this? For example, if we have the equation $x^3 + x^2 + x + 1$, how can we plot the 3 roots as ...
3
votes
2answers
277 views

Tweaking Solve for systems of polynomial equations

I am trying to solve the following system of $6$ quadratic equations in $6$ variables: ...
3
votes
1answer
530 views

Monitoring the Evaluation of NDSolve: time to finish estimation

My problem is quite simple: I run a NDSolve with a system of many ODEs, a calculation that will run for many hours, and I would like to know the progress of the ...
3
votes
0answers
64 views

Non-preemptive evaluation of a dynamic function? [duplicate]

I want to monitor a long calculation that is triggered by the release of a Slider. While one can indicate running calculations when the main evaluation loop is ...
3
votes
3answers
394 views

Symbolic derivative of $n$-term product

I want to determine the relationship that must exist between the $x_i$ and $y_i$ such that $$ \frac{\partial}{\partial\theta} \prod_{i=1}^n \frac{f(x_i,\theta)}{f(y_i,\theta)} = 0, $$ where $$ ...
3
votes
4answers
387 views

Make function return unevaluated equation

I have made this function which outputs the equation of a nth degree polynomial: ...
3
votes
2answers
438 views

MathLink and CDF

So far I have read that some things are not supported in CDFs. Istvan-zachar mentioned very useful things in his post. Unfortunately he mentioned that MathLink operations, including J/Link and ...
3
votes
2answers
235 views

How can Magnify be forced to ignore the notebook's window width?

In a new notebook, I can illustrate how the action of Magnify is cut off by the window width: ...
2
votes
1answer
258 views

Model fitting to noisy data with a custom minimization function

I'm looking into fitting some data with Mathematica. I've got my head around how NonlinearModelFit works (I've been using the Levenberg-Marquardt algorithm for some ...
2
votes
3answers
336 views

Writing a simple application: interactive quiz for multiplication table practice

I am trying to write a very simple application in Mathematica: a quiz that tests a multiplication table(let's use the 9x9 for this example). The app will display a question(e.g. 7x5), and the user has ...
2
votes
4answers
479 views

How to calculate the position of a figure in an image?

My question is about recognising soccer players in the pitch. Thanks to Bill S who wrote an excellent script to recognise parts of the players. I found this issue after testing his solution. I will ...
1
vote
1answer
213 views

Display a labeled multigraph

Despite the integration of graphs and networks, multigraphs are not supported in Mathematica 8+. In Mathematica 9+, GraphPlot misbehaves for multigraphs having ...
0
votes
1answer
2k views

Complex line integral

Can someone recommend an online article or introductory tutorial that will show me how to do real and complex line integrals using Mathematica?
18
votes
2answers
392 views

Is Compress[] compatible between different Mathematica versions?

Compress[] was introduced in version 6 of Mathematica. It gives a compressed version of expressions represented as a string of ASCII characters. It preserves more ...
17
votes
1answer
234 views

Total much slower in version 10

Compilation nowadays may give very fast functions. Here is an example for finding the sum of a list of machine numbers, just as the built-in function Total: ...
16
votes
5answers
1k views

How can I create a rectangular graphic with curved edges?

I want to make some button shaped graphics that would essentially be a rectangular shape with curved edges. In the example below I have used Polygon rather than ...
16
votes
2answers
340 views

When should I, and when should I not, set the HoldAll attribute on a function I define?

I have seen a number of examples on this site (such as in syntax highlighting and checking evaluation status) in which functions definitions are preceded with ...
16
votes
4answers
1k views

Random data generator

Inspired by Quality of random numbers I would like to set up a true random data generator in Mathematica. My idea is to use the static from an open microphone. I recall reading about extracting the ...
15
votes
2answers
334 views

Obtaining the number in CounterBox

Is there a way of obtaining the current number of a counterbox? Say for instance that in a new notebook you create 3 section cells. Then by evaluating the command: ...
15
votes
5answers
625 views

How do I generate the upper triangular indices from a list?

I have some list {1,2,3}. How do I generate nested pairs such that I get {{1,2},{1,3},{2,3}}? That is I'd like a way to ...
15
votes
2answers
896 views

Why does Mathematica give the wrong answer when integrating?

I integrate Integrate[Exp[I Cos[b - c]] Cos[b], {b, 0, 2 Pi}] Mathematica gives: 2 I Pi BesselJ[1, 1] Which is indepedent ...
15
votes
2answers
608 views

Lexicographic ordering of strings in Mathematica

I recently realized that Mathematica seems incapable of comparing strings in the "normal" expected lexicographic order. Indeed, for some simulations, I need to process text directly, without fiddling ...
14
votes
1answer
240 views

How to programmatically remove menu items

I would like to do the opposite of what is described here. So rather than add a menu item I would like to programmatically remove one (or more). So given a knowledge of the structure of the menu *.tr ...
14
votes
2answers
1k views

Fastest way to measure Hamming distance of integers

I am looking for a fast and robust way to calculate the Hamming distance of integers. The Hamming distance of two integers is the number of matching bits in their binary representations. I expect that ...
14
votes
6answers
615 views

Matrix Rotation

If I have a matrix of any size, say $\begin{pmatrix} 72 & 32 & 64 \\ 18 & 8 & 16 \\ 63 & 28 & 56 \\ \end{pmatrix}$ $\begin{pmatrix} 72 & 32 \\ 18 & 8 \\ 63 ...
14
votes
3answers
1k views

Is learning to use Mathematica useful for pure theoretical research in Mathematics and Computer Science?

I am looking for opinions from Mathematica users about Mathematica itself. After reading the faq, I thought that in some sense I "wish to solve a problem using Mathematica" ... although I understand ...
14
votes
1answer
389 views

When to use built-in Graph/GraphPlot vs. Combinatorica

What are the pros and cons of using built-in Graph/GraphPlot (and related) types vs. types in the Combinatorica package?
14
votes
2answers
52k views

Generate a Unit Circle Trigonometry

Struggling often with Trigonometry I would like to have some code to generate this Unit Circle Trigonometry. Would be of great help when I need to transform some data :

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