# All Questions

868 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! ...
524 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 ...
343 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: ...
646 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 ...
922 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 ...
657 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 ...
251 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 ...
635 views

198 views

### How to find longest monotonic sequence?

I have a list, for example list = {2, 1, 3, 5, 4, 6} How to find longest ascending sequence of this list? There are two meanings of this question: Find the ...
447 views

Running InstallR["RHomeLocation" -> "C:\\Program Files\\R\\R-3.0.1"] results in a popup box titled "Version Mismatch" saying Error: R.DLL version does ...
281 views

For convenience I'm trying to add an extra property to CountryData ...
692 views

### Second level depth pure function?

I have the following working construction: Select[ln125, # == Nearest[ln125, 551.748][[1]] &] Here, ln125 is a one ...
258 views

### Construct an infix operation from a list

Inspired by this question, if I have a list {a, p, b, q, c} where p and q are binary ...
934 views

### Derivatives (divergence, gradient, curl) of interpolated 3D data

How can I calculate a vector derivative (i.e. divergence, gradient, curl) of interpolated data? For sample data, you can use: ...
174 views

### Emulating Sequence with my own function

I just considered if/how one could implement Sequence in Mathematica if it were not predefined. It turned out that the following simple definition has in all my ...
603 views

### Google Code Jam: Mountain View code review

After participating in Google Code Jam 2012 Round 2, it occurred to me that the Mountain View problem boiled down to solving a set of linear inequalities, which could be done in Mathematica. I've only ...
326 views

I want to make a function that takes a function as a parameter and prints an integral with the function inside. I've tried this: ...
1k views

### How to export transparent raster plots?

Is there an easy way to get transparent plots that work with Save Graphic As using a compatible file format such as GIF or PNG? I tried ...