10
votes
2answers
91 views

How to use `Except[]` inside of `Pick[]` [duplicate]

Pick[{1, 2}, {0, 1}, Except[0]] returns {1, 2}, the first element of which I did expect to be excluded. What is the thing I ...
10
votes
2answers
447 views

Recursive Integral for Volume of $n$-Ball

The volume of an $n$-ball (the $(n+1)$-dimensional analogue of a disk) of radius $r$ can be found by the following integral recurrence: $$V_0(r)=2r$$ $$V_n(r)=\int_{-r}^rV_{n-1}\left(\sqrt{r^2-x^2}\...
10
votes
4answers
371 views

Efficient way of identifying the indices of first occurrences

It seems to me like identifying the first occurrence of unique elements should take about the same amount of time as it takes to delete duplicates. My data sets are much larger than this (...
10
votes
3answers
292 views

Mathematica equivalent to Python long raw strings? handling escape characters in packages

I'd like to write the following in plain text .m file in Mathematica, without having to double escape all the Latex commands: ...
10
votes
2answers
203 views

ParallelTable behaves differently when it is run inside a package

I've been butting my head against some very weird behaviour by ParallelTable, and its interaction with packages, over the past few weeks, and making relatively ...
10
votes
3answers
2k views

Programming Mathematica in plaintext, i.e. no formatting, non-notebook

I'm new to Mathematica and I've just begun reading Paul Wellin's Programming in Mathematica. The book, like many other books and online tutorials, revolves around using the notebook, with all its ...
9
votes
0answers
346 views

J/Link doesn't work with Java 8?

I have some code that successfully uses J/Link (well... until today when something I was doing something with it that crashed the JVM, so), and I recently tried running it under Java 8. I then get a ...
9
votes
3answers
518 views

How to make a picture grid of all Nobel Laureates in physics?

I want to make a picture grid of all Nobel Laureates in physics using mathematica. Later I wanna print this picture grid on a big wall! The first thought I came up with is to exploit the powerful ...
9
votes
0answers
126 views

Esc-esc for special characters and autocomplete in Mathematica 9 [duplicate]

I recently upgraded to Mathematica 9 and have noticed a slightly annoying behavior that I was looking to remedy. In the past I would type special characters, e.g. ...
9
votes
1answer
439 views

How can I replace the Greek symbols in an expression with their plain text names?

Suppose I have an expression with Greek symbols in it. How would I convert that expression to another expression where the Greek symbols have been replaces with their names in plain text? I've ...
9
votes
3answers
164 views

DSolve—different solutions for same set of equations using different symbols?

I happen to find that DSolve can give different solutions, even a different number of solutions, for a set of differential equations just by making a change in the ...
9
votes
3answers
495 views

FindShortestTour for charity (or: How can I optimize meal delivery with FindShortestTour?)

I've been wondering about this for a while - but never got around to asking - until I saw faleichik's incredible answer to Mathematica Minecraft. I did some work at a not-for-profit a little while ...
9
votes
2answers
264 views

How can I tell how much memory is taken by an expression?

ByteCount and LeafCount don't really work, as shown below. Mathematica 9.0 on a 32-bit Windows machine: ...
9
votes
1answer
431 views

Laplacian and DiracDelta

It is known that: $\nabla^2 \dfrac{1}{|r-r'|} = - 4 \pi \delta^3(\vec{r}-\vec{r}')$. If I do that with Mathematica, I find: ...
9
votes
3answers
958 views

Converting datasets to nested lists

Imagine the Shipments relation: ...
9
votes
1answer
1k views

Mathematica memory management for large arrays

I have come across a weird phenomenon in Mathematica when dealing with large arrays. When generating a list with all the possible subsets of three elements of another list (thus having elements which ...
9
votes
1answer
896 views

how to simplify large expression with lots of special functions in it (BesselY, Hypergeometric, MeijerG etc…)

I saw this DE in Maple forum. When solving it using Mathematica 9.01, even though the result was correct (both solutions gave the same numerical answer for some random values), Mathematica's answer ...
9
votes
1answer
1k views

How to stop the Kernel from running wild?

How to abort or stop this (accidently large defined) SparseArray production? s = N[SparseArray[Table[{2^i, 4} -> i, {i, 30}]]] Alt+. or Alt+, seem to give ...
9
votes
2answers
391 views

Any packages for vertex enumeration on Mathematica?

My work requires me to enumerate all vertices of a polytope defined by linear inequalities from time to time. And I'm mainly working with _Mathematica 9.0 on Mac OS X 10.9. So I wonder are there any ...
9
votes
2answers
207 views

How to define UpValues in a different context from within a package

I'm trying to create a function (in a package) to import a lot of data and create a symbol with UpValues to return specific results about the data. I've got it working fine in a regular notebook, but ...
9
votes
7answers
323 views

Input a square matrix and return a list of the matrix entries read by antidiagonals

I have a square matrix: {{1,2,3},{4,5,6},{7,8,9}} and I want to get a list: {1,2,4,3,5,7}
9
votes
2answers
135 views

Animating a growing ListPlot

I stumbled upon this (rather contrived but interesting) integer sequence. As it exhibits quite different behaviour at different scales, I would like to generate an animated ...
9
votes
2answers
218 views

Checking from a preemptive evaluation whether a main evaluation is ongoing

How can I programmatically check from a preemptive evaluation whether a main evaluation is currently ongoing? I need a function mainEvaluationOngoingQ[] so that <...
9
votes
6answers
338 views

Adding list of list to a list

Hello I need some help on how to add a list to a list of list. The program would have to do as below: {{0,0}, {0}, {0,0,0}}+{1,2,3,4,5,6} will give ...
9
votes
5answers
575 views

How to resize the text content of a grid with it?

I am in a resizing mood these days. This code works quite well, up to a point. ...
9
votes
1answer
346 views

How to check for Mathematica’s definition of XY?

The question is: Can I ask the Mathematica kernel directly what it takes as the definition of the built-in symbol XY? After all this has to be in the kernel. And if the documentation is not giving any ...
9
votes
3answers
477 views

Trouble getting FindInstance to return multiple results for certain constraints

I'm having a hard time getting FindInstance to return multiple results. Consider this simple example: ...
9
votes
3answers
367 views

Operate over list of pure functions

I have list of pure functions (All functions are InterpolatingFunction) i.e {{a, b}, {c, d}, {e, f}, ...} and I would like ...
9
votes
1answer
248 views

in v9, backspace causes cell to become section style

In the front end of v9, in any given cell that contains content, if I hit backspace to clear the content until there is nothing left, and then hit backspace one more time, the cell becomes a 'section'....
9
votes
1answer
1k views

detecting the radius of an incomplete circle

I need your help to detect the radius of the blue circle in images like this: . Reading these questions: 1, 2, 3, I figured that this code taken from @halirutan answer to question n°3 could help: <...
9
votes
2answers
886 views

How to generate a matrix group?

I have three $7\times 7$ matrices (with real entries, lots of zeros) and I'd like to check if they generate a finite group (or, more precisely, if the group they generate is of precise order). Would ...
9
votes
3answers
1k views

How to typeset a system of equations

Is it possible to typeset systems of equations in Mathematica, and if so, how can I do it using a big left bracket as one could in LaTeX with \left\{ ... \.? I ...
9
votes
2answers
295 views

Median of Dataset in Mathematica 10

Bug introduced in 10.0 and fixed in 10.3 I'm having trouble calculating the median of a Dataset[] in Mathematica 10. The situation is as follows. Consider a ...
9
votes
1answer
912 views

How to calculate the $H_2$ and $H_\infty$ norms of TransferFunctionModels or StateSpaceModels?

Lets assume we have a system model: ...
9
votes
1answer
402 views

FEM: how to choose FEM element type

I am asking myself if there is any simple option for choosing the element type for the mesh generation WITHOUT explicitly creating coordinates and then the mesh. Minimal example: here I would like ...
9
votes
5answers
988 views

Fast way of finding position of Interval containing an Integer

I have a large list (about 2.2 million) of pairs of integers. Each pair defines an Interval[{}]. Given some integer x, I need to ...
9
votes
2answers
328 views

Extracting values with multiple keys

I want to extract sorted data from a huge database based upon two (or more) keys in a very timely manner. Here is a reproducible toy example for two keys only: ...
9
votes
1answer
85 views

How to put Magnification control in docked cell

I have made a handy toolbar that provides access to menu items that are not visible when I F12 a workbook. I would like to add the following function to a button in the toolbar: ...
9
votes
1answer
149 views

How to test if file exists on the front end machine?

When using a remote Mathematica kernel, how can you test if a file exists on the local front end machine? Of course FileExistsQ cannot be used in this scenario, ...
9
votes
2answers
2k views

Epilog->Inset crops text with large font sizes

Why does Epilog->Inset crop the first and last letters here ("a" and "g") when FontSize is set to large values (which varies ...
9
votes
1answer
565 views

Generating high quality charts in Mathematica for use in LaTeX and Word

I frequently have a probelem using my charts in reports because the text (axes labels and tick marks) look low resolution (fuzzy). When I export my charts, i export them as PNG files. Unless I'm ...
8
votes
2answers
295 views

FWHM of an image

What is a resourceful method to calculate FWHM (full width at half the max) of every column in an image. Assuming the image is having a very high resolution for example 1944 x 2592. Logic so far (...
8
votes
1answer
614 views

Computing the Hurst exponent or fractal dimension of fractional Brownian motion

The Hurst exponent is related to the fractal dimension by noticing that the fractal dimension $D$ is equal to $2-H$, where $d$ is the intrinsic dimension and $H$ is the Hurst exponent, for 1-D ...
8
votes
4answers
642 views

Fast method to select matrix elements based on a vector of positions

There is an operation for which I have long wanted to find a better solution. Let: a be a matrix of dimensions $m\times n$ v...
8
votes
3answers
182 views

How can I use the overhang argument to Partition to avoid using PadLeft and PadRight here?

Say I have a list of values v = {v1, v2, v3, ... }. I need to partition these values to perform operations with a sliding window (think ...
8
votes
1answer
299 views

Mathematica AppData folder is taking up too much space

I recently made a small app that I had issues with. I'm pretty sure it ended up being because of all the curated data to load. My problem now is that under the Windows 8.1 folder Users/Username/...
8
votes
1answer
153 views

Has anybody been able to build WSTP applications under Visual Studio 2015's IDE?

I recently picked up an old project involving WSTP (formerly MathLink) programs, and as a starting place tried to get the demos provided by Wolfram to compile. The instructions were dated, referring ...
8
votes
1answer
3k views

How can I connect to a database using the 32 Bit ODBC on a Windows 7 (64 Bit) machine?

I am having difficulties using a DSN that was defined in the 32 Bit version of the ODBC-manager? (there are two separate managers for 32/64 Bit on a 64 Bit machine) Using the DatabaseLink package ...
8
votes
1answer
619 views

Anti-aliasing a fractal-like bitmap image

I have a .bmp image 9600x5400 that shows a lot of points at various intensities. There are no lines inside this picture - only a lot of points. I would like to apply anti-aliasing on the image to make ...
8
votes
1answer
867 views

Integral of the Sinc product

Let as consider the following integral $$ B_n = \int_0^\infty \prod_{k=1,3,5,\dots}^n\frac{\sin (x/k)}{x/k}dx $$ By definition, Sinc[x]=Sin[x]/x therefore ...

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