4
votes
3answers
393 views

Slow image manipulation

This is some extremely simple code that shows an image and manipulates a circle (that will be used to select a region of the image to analyze). All those Dynamics ...
4
votes
2answers
376 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
487 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
293 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
1k 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
419 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
206 views

Partitioning time series

I have a time series dataset I'm trying to plot by Year: ...
3
votes
2answers
291 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
2answers
616 views

Generating x,y coordinates for an edge detection

I'd like to be able to process a number of graphics that have edge contours and output a list of $x$, $y$ coordinates to be used for generating a spline in another program, or in Mathematica, to make ...
3
votes
1answer
613 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
1answer
858 views

Detection of horizontal lines in an image

Ok I'm trying to detect horizontal lines in an image. But the problem is that the line is quite obscure. So I'm not sure if it is even possible to extract that. I tried many different filters, but ...
3
votes
2answers
627 views

NDSolve: Normalizing at every step

Suppose I have an transport equation with an initial conditions: ...
3
votes
0answers
66 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
425 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
432 views

Make function return unevaluated equation

I have made this function which outputs the equation of a nth degree polynomial: ...
3
votes
2answers
447 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
247 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
3answers
402 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 ...
1
vote
1answer
244 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?
-3
votes
1answer
3k views

Determine the 2D-Fourier transform of an Image

I am new to Mathematica and using Version 8.0. I want to calculate the 2D-Fourier Transform of a digital image and see its Magnitude and Phase Spectrum, and reconstruct it.
20
votes
2answers
369 views

Can Mathematica solve Plateau's problem (finding a minimal surface with specified boundary)?

Given a closed curve $\mathcal C$ in three dimensions, is it possible to use Mathematica's built-in functionality to compute a minimal surface whose boundary is $\mathcal C$? For simplicity, let us ...
20
votes
1answer
394 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: ...
20
votes
2answers
412 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
1k views

How often does Mathematica contact its license server?

I know that Mathematica checks the validity of its license every time the program is launched. Say, however, that I have a valid license (which I do) and that I am running some code which takes a ...
17
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 ...
17
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
4answers
904 views

Measure perimeter of black edge in Mathematica

I have a pattern like the one below. How could I measure the total length of the perimeter of the black/white edge? This would give me a measure of spatial frequency. Any tips would be great! Thanks! ...
15
votes
4answers
545 views

Accessing Reduce from DSolve

When solving transcendental equations, Solve frequently warns us that inverse functions are being used so that some solutions may not be found. We also see that ...
15
votes
2answers
350 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
649 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
940 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
679 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
256 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
6answers
643 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
393 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
994 views

Is Mathematica a Turing-complete language?

Is Mathematica a Turing-complete language? If so, how can that be proved? If not, why?
14
votes
2answers
55k 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 :
14
votes
5answers
2k views

sprintf() or close equivalent, or re-implementation?

Is there a sprintf() command (some command that takes a printf-style format string and a list of values to insert into the ...
13
votes
2answers
510 views

Phase portrait on a cylinder

It is very nice and very easy to make a sketch of a phase portrait with StreamPlot. For example, for the classical pendulum, defined by $$ \dot x=y,\\ \dot y=-\sin x, $$ The code ...
13
votes
2answers
277 views

Export Plots to PNG in Printout Style

When creating a plot in Mathematica 10 (OS X 10.9.4 and Win 7) the FrameLabel and Ticks are greyish and only the Frame itself is black (see Screenshot bellow). Only when exporting the plot to PDF all ...
13
votes
1answer
263 views

How to determine numeric equivalent of Tiny, Small, etc. image sizes for Graphics?

Is there a way to find the numeric equivalents of Tiny, Small, Medium, and ...
13
votes
0answers
167 views

func::usage needs to be run twice? [duplicate]

There is an annoying problem that I can't figure out why it's happening. I have defined a usage for a my function tensorA: ...
13
votes
4answers
2k views

How do I plot the unit normal field for a surface?

The question is pretty much in the title; I'm about to teach my multivariable calculus students about orientations on surfaces, and I would like to be able to show them pictures. Any ideas?
13
votes
3answers
298 views

How to keep some of the results of the NestList

I'm using some iterative arithmetics to calculate wave propagation with the help of NestList. I have to use a small step size for iteration to guarantee the accuracy, which lead to too much data (e.g, ...
13
votes
2answers
898 views

Suppressing negative roots in Mathematica

Problem Using Mathematica's Solve operator can sometimes lead to an output involving a positive and negative root (say when solving for a variable such as ...
13
votes
1answer
397 views

ImageAlign doesn't always work correctly

I've been working with ImageAlign in Mathematica 8 and I'm having trouble getting it working reliably. Perhaps there are some subtleties that I'm not yet aware of? ...
12
votes
3answers
156 views

What kind of check does DirectoryQ exactly perform?

I'm using Mathematica 9.0.1 on Windows XP and my drive letters are assigned as follows: C: and D: are hard local disks, while ...
12
votes
6answers
637 views

Elegantly split a matrix into positive and negative parts?

I have a matrix $M$ of real components, and I want to split it into two matrices $M^+$ and $M^-$ of the same dimensions as $M$, where $M^+$ contains the positive components of $M$ (the remaining ...

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