8
votes
3answers
1k views

Discrete Convolution

Ask to compute the convolution of 2 lists, I managed to do so, with what I feel is rather heavy : Let my 2 lists be : a = {1,2,3,4} b = {1,1,1,1,1,1}; The below function adds 0s on each part of ...
9
votes
2answers
874 views

Expand modulus squared

Is it possible to make a function in Mathematica that expands expressions of the form $$|z + w|^2 = |z|^2 + 2\text{Re} \overline{z}w + |w|^2?$$ Preferably it should also be able to handle things ...
7
votes
2answers
4k views

Does Mathematica implement the fast Fourier transform?

Is there a fast Fourier transform in Mathematica? Although looking in the help I could not find one. I am looking to implement the equivalent of fft in MATLAB.
3
votes
2answers
319 views

Conditional T distribution

Suppose $(X,Y)$ has a bivariate t distribution. I want to plot the density of the conditional density of $Y$ given $X$, i.e. $Y|X$. I wonder why the following does not work: ...
5
votes
1answer
261 views

Alternative to overloading Set

In the ideas shared in my answer to this post Struct equivalent in Mathematica? at the end I propose a solution that changes the way Set works in a particular case that can be expressed in plain words ...
5
votes
4answers
652 views

MySQL Connection Problem

I have a problem with the configuration of the J-Connector plug-in with a MySQL database. Most of the time all works well, but sometimes the connection remains blocked for 2 hours and then it gives ...
0
votes
3answers
364 views

Silence debug output from Parallelize?

I have this script, which does a bunch of image aligning in parallel: https://gist.github.com/8848a25a15da013ed1ad However, on EVERY print, Mathematica also prints from what Kernel the message came ...
5
votes
1answer
370 views

Invisible \[Conjugate] glyph in the linux frontend

I have a very annoying problem. The Conjugate glyph (*) does not show when I type. That is, if I type \[Conjugate] or ⋮co⋮ then ...
15
votes
1answer
593 views

Can the position of Tooltips be changed?

Is it possible to change the position of tool tips, which currently always appear to the lower right of the mouse position. In the screen grab below the mouse is over 10000000 and the tooltip appears ...
3
votes
1answer
170 views

Generate a new output using Manipulate

Thanks to methods found in the below, I was able to assemble those elements : Tile image on specific location without space between them How to combine images with the same dimensions in a grid? ...
4
votes
0answers
238 views

NullSpace[_, Method->“OneStepRowReduction”] is sometimes wrong; how can I work out when this happens?

(This is on MMA 7.0.1.0 on OS X) I've just found a large matrix m for which NullSpace[m] and ...
3
votes
2answers
184 views

Cleaning up a List of HTML Data to Render Usable Information

I am using Mathematica to scrape information from webpages. To get file information, I am gathering plain text that is enclosed by <tr> and ...
41
votes
7answers
1k views

How to “Copy as Unicode” from a Notebook?

I spent some time manually editing a post replacing Mathematica ASCII \[Alpha] with Unicode α. I did this by laboriously ...
18
votes
3answers
884 views

Removing In/Out Labels before printing

I know that I can close a notebook and open it again in order to remove the In/Out labels. What I would like to know is if there is another easy way of removing these labels without having to close ...
16
votes
3answers
2k views

Plotting piecewise function with distinct colors in each section

I have a piecewise function that I would like to plot but I was wondering if it is possible that each part of the function that is plotted when its corresponding condition is true be plotted with a ...
22
votes
3answers
614 views

Which Distributions can be Compiled using RandomVariate

Recently, Oleksandr kindly showed a list of Mathematica commands that can be compiled. RandomVariate was part of that list. However, whether this can be compiled depends upon the distribution that is ...
7
votes
3answers
672 views

Efficient image Import

I have several sets of 20 images I need to import. Each time they have different categories. "Name"<>"Cat"<>"No" Electric B 1 for example. I need to create lists that contain the images ...
16
votes
2answers
609 views

Built-in Mathematica data: are they cached? how to speed up the loading?

Mathematica has numerous built-in data for science and math. Every first call to a data function in a new Mathematica session will "re-initialize indices" (download the data). Is there a way to store ...
4
votes
1answer
646 views

Why these (error) messages?

Testing this answer I used: stream = OpenWrite["A:\\out.txt"]; Block[{$Messages = stream}, Mod[1, 2, 3, 4, 5] ] and I was surprised to find that the contents ...
25
votes
1answer
534 views

Is it safe to launch/close kernels in the middle of a parallel calculation?

It appears that it is possible to launch additional kernels (or close existing ones) during a parallel calculation. The newly launched kernels will be utilized for the rest of the calculation. ...
7
votes
3answers
328 views

Making sure that Timing[] isn't thrown off by caching

In playing with and comparing the various answers to my question here, I tried applying Timing[] to see how fast things ran, but it seemed that some of the answers ...
0
votes
1answer
137 views

FE`symbols that remain in notebook internals even after removing them and SaveDefinitions->True issue

How does one clear the notebook from symbols that remain in it after an edit session?
5
votes
1answer
145 views

Bug in LengthWhile?

Is this a bug or my MMA went insane or I'm missing something? LengthWhile[Reverse@IntegerDigits[1000], # == 0 &] works fine, but with SameQ instead of Equal, ...
73
votes
8answers
6k views

List of compilable functions

Is there somewhere a list on the functions that Compile can compile, or the cases in which a particular function can be compiled that I haven't found? I'd be glad ...
23
votes
6answers
1k views

efficient way to count the number of zeros at the (right) end of a very large number

If I want to count the number of zeros at the (right) end of a large number, like $12345!$, I can use something like: Length[Last[Split[IntegerDigits[12345!]]]] ...
5
votes
4answers
350 views

Some windows go off display

(I'm navigated from stackoverflow.com where I asked almost the same question) When I want to use additional windows, let's say for example "Basic Math Input", I feel reluctant to find visually where ...
5
votes
6answers
1k views

bar and hat only apply to certain letters

(I'm navigated from stackoverflow.com where I asked almost the same question) I'm a beginner in Mathematica. Like shown in the image below, I'm trying to put hat ...
12
votes
3answers
271 views

Memoization of Rounded inputs

Memoization is a technique for improving performance by having a function remember its previous arguments. For example, f[x_]:=f[x]=mySlowFunction[x] will be ...
15
votes
7answers
2k views

How to express an integer number in English words?

How do I convert a number to a readable string? I would like to implement a function, inWords[], inWords[n_]:= ? which ...
13
votes
2answers
843 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 ...
9
votes
2answers
334 views

Is it possible to set a timeout for LinkWrite[]?

This came up in relation to this answer Is it possible to set a timeout for LinkWrite? LinkWrite seems to block until the sent ...
10
votes
2answers
1k views

How to improve the typesetting of mathematical contents

Until I started diving into Mathematica, I was not using much computer software for symbolic computation. I did my analysis by hand on blank sheets, the calculations using Python or MATLAB, and the ...
9
votes
6answers
1k views

Producing cleaner Mathematica output

I asked this in chat and it turns out it would make for a good question make a posting for. I am writing up a handout type notebook and I'd like to have some clean output for presentation's sake. ...
10
votes
2answers
207 views

How to Write into multiple files?

Note: this is fixed in version 9. I want to put expressions into multiple files simultaneously, with the following code: ...
8
votes
1answer
378 views

How to pipe a stream to another notebook?

Can I pipe an OutputStream object created by OpenWrite (or similar) to a notebook instead of a file? I am aware that I can use ...
9
votes
2answers
249 views

MouseAppearance and cursor problems

I have to create a Graph object, which can be manipulated by the user, though I do not want to have the Graph-specific cursor ...
4
votes
2answers
224 views

How to Text justify string that includes SubScriptBox in it?

I am using Grid to document a demo I have. i.e. I am writing the documentation of the demo as a help option, which will display information when clicked on. Everything is working well. I am using the ...
7
votes
1answer
870 views

How do you get high resolution plots in applications using the Mathematica MathService?

This is for Mac users only using MathService (MathService it seems, given that it was created back in 2004, is a power pc code and requires Rosetta to run on Intel). If I type a plot command in ...
10
votes
6answers
1k views

2D Gaussian distribution of squares coordinates

I would like to imitate the structure of this great painting from Ellsworth Kelly in Mathematica. Yet with all the colored squares in Black and the beige one in white. Below is what I have wrote to ...
27
votes
4answers
2k views

Is it possible to speed up ContourPlot on multi-core machines?

It is not very difficult to face a function for which ContourPlot works too slow. And it seems natural that this function can be parallelized well. Anyway, naive ...
4
votes
2answers
188 views

Problem with EllipticE documentation

The complete elliptic integral of the second kind, EllipticE, is defined as, Integrate[Sqrt[1-m Sin[t]^2],{t,0,z}] According ...
21
votes
1answer
453 views

Is there an equivalent of FullGraphics for Graphics3D?

For 2D graphics, there exists the function FullGraphics to turn the stuff Mathematica generates automatically on Graphics (like ...
77
votes
7answers
7k views

Struct equivalent in Mathematica?

I really miss having something like a struct in Mathematica. I know of (and regularly use) a couple of programming techniques which feel like a ...
21
votes
3answers
1k views

How to find pieces of code responsible for syntax errors?

Especially: How to find the piece of code responsible for a missing parenthesis problem caused by a misplaced SuperScriptBox For last 30 minutes (and I was lucky ...
17
votes
6answers
751 views

On generalizing Partition[] (with offsets) to sublists of unequal length

The usual Partition[] function is a very handy little thing: ...
15
votes
4answers
717 views

How can I create a ColorFunction using Blend?

As shown below, I am trying to find a cool way to show some variance weighted deviation from the mean. There are 10 attributes that I compute the distance for. How can I add a color function such ...
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 ...
1
vote
4answers
3k views

Creating a data1 versus data2 plot?

I have a table of data with multiple rows and columns, and I have to make a versus data table using two of these columns. Essentially, I have to set one column of data (column 3) as the y-axis and ...
7
votes
4answers
1k views

Styling ticks, axes and other elements in a Plot of a step function

To display the effect of uniform quantization (step size Q) I would like to draw a curve as shown below I tried this using ...
11
votes
7answers
2k views

Combination and Permutation

How could I obtain the list of all the groups of 5 numbers taken from Range[12] such that the 2 lists have an empty intersection : ...

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