# All Questions

208 views

### How to compile a diagonal array efficiently?

For example, if we use some functions defined prior to Compile, we usually have the main evaluators in the compiled codes, pointing to the definition of the ...
551 views

### Replace For-loop with functional code

I am very new to Mathematica. I have code written using for loops. I want to rewrite it using Map/Thread but I am not sure how ...
174 views

### Alternative updating of a dynamic expression

I am looking for a solution to selectively update a dynamic expression expr which is dependent on multiple control variables ...
610 views

### Transparent Cylinder with Dashed Edges only

I would like to have that kind of cylinder with Dashed edges (including the bellow inner ring): I've been trying that: ...
981 views

### Non-commutative algebra

I'm constantly dealing with non-commutative algebras. ** is inbuilt, non-commutative and associative. That's good :-) But it is not distributive. Rats. ...
310 views

### Execute code when file is modified

I have a function the takes some time to complete. The function imports data from a .csv, parses it, and plots certain vectors from there. The .csv is constantly being updated from an external ...
927 views

### ListPlot3D - How to make the Color depending on a second list

From a simulation (solid state physcis) i obtained a list1={{300,0,0},...} with x values=300,400,...,1500 and y-values=0,0.08,...,20 and z values. I plotted them ...
357 views

### Replacing gamma at half integers by double factorial

It is well-known that for any positive integer $n$ the equality $\Gamma(n+\frac12)=\sqrt\pi\,(2n-1)!!/2^n$ holds, where $!!$ stands for the double factorial. I am using ...
867 views

### How to Plot Prism in Graphics3D

I want to create an image of a rectangular prism, but there is no built-in primitive for it. One method to display a prism is shown in whubers's answer to Mathematica for teaching orthographic ...
659 views

### All possible solutions to the Matrix Equation (free variables appearing)

I am attempting to solve a system of linear equations using LinearSolve[] . In my case, the number of unknowns are more than constraints. I learnt that LinearSolve ...
877 views

### Interpolating 2D data with missing values

I have a list (21 x 21) containing values. I want to eliminate slots containing zeros by interpolating the nearest values and overwriting the zeros. How do I use the Mathematica's ...
325 views

### What's the correct method to simplify exponentials?

I have a sum of exponentials that I'd like to simplify. The issue is when I use Simplify, Mathematica loves to factor out one exponential factor. See below: e^{-i ...
804 views

### How can I get even steps on x and y axes in a plot?

I'm plotting the shortest distance from a point to a line using the following code ...
3k views

### How do I troubleshoot when I get a Part::partd or a Part::partw error?

Mathematica has produced the following error message: Part::partd: Part specification ... is longer than depth of object? What is partd? I think I may ...
349 views

### Replace with position and order number

question conversion1 : Convert "[AA]AB[AA]BB[AA]B[AA]CCC" to "[A1A2]A3B1[A4A5]B2B3[A6A7]B4[A8A9]CCC" conversion2 : Convert ...
379 views

### Excessive memory use by Mathematica kernel in 10.0.2 after executing simple commands

Warning: the code below may hang your system if you have the Suggestions Bar enabled. When issuing the following simple statements to Mathematica, it responds with a valid answer. However, ...
470 views

### Getting lengths of sublists that sum to more than one

I have a long list of numbers, and I'm interested in finding the length of each sublist that totals to more than 1, so for the list ...
835 views

### Plot Option Precedence while combining Plots with Show[]

I like to build sophisticated plots by combining simpler ones with Show[]. Typically this involves setting non-default Plot-Options with the different ...
309 views

### Adding three integer sparse matrices is very slow. Adding only two is fast

Adding more than two sparse matrices in one step in Mathematica 9 is very slow (in fact I couldn't even wait for it to finish). Here's an example. Let's generate a large sparse matrix: ...
688 views

### How to use Union on list of lists without sorting them first?

If I do ClearAll[a, d] lsts = {{a, d}, {a, d}}; Union[lsts] I get the expected answer {{a, d}} but if I do ...
2k views

### What method does NDSolve use for solving PDEs?

What is NDSolve's mode of operation? I use it to solve partial differential equations and never gave it too much thought. Recently, I came across this question. ...
262 views

### Bizarre behavior of With, Compile and Break

I'm guessing this is almost certainly a bug in Compile (because they're fairly common), but it's pretty weird and I spent about an hour tracking down the issue and ...
339 views

### How to replace every possible $A+B$ and $AB$ in expansion of $(A+B)^{10}-A^{10}-B^{10}$ with $x$ and $y$, respectively?

I would like to replace every possible $A+B$ and $AB$ in expansion of $(A+B)^{10}-A^{10}-B^{10}$ with $x$ and $y$, respectively. How to do it with the simplest code in Mathematica? For example, ...
190 views

### Why can't I use Sequence to perform a Select like task? [duplicate]

Suppose I wanted to write down a list of $p^2$, for $p$ a prime between $1$ and $20$. I would expect Table[If[PrimeQ[k], k^2, Sequence[]], {k, 1, 20}] to work. ...
688 views

### Ordering vertices in GraphPlot

I'm new here, so forgive me if this question is not well-posed/duplicates an earlier question - although I've searched for similar questions without success. I'm trying to present a plot of ...
409 views

### TableAlignments -> Left not working

Bug introduced in 7.0 or earlier and persisting through 10.0.2 or later For a very simple dataset TableAlignments->Left does not work: ...
596 views

### Delete duplicates in a list, depending on the sequence of numbers

Below, list is a representative sample of my list, which contains lists of integers. I would like to be able to input: ...
105 views

### Resizing or moving Notebook window causes Manipulate to update its argument

Check this example: Manipulate[Grid[{{RandomReal[10]}, {Plot[Sin[x], {x, 0, 2 Pi}]}}], {a, 1, 3}] As you can see, moving or resizing the Notebook window causes ...
491 views

### Non-geometric transformation of Graphics3D primitives

I want to apply non-geometric transformations to polygons etc, the goal is to have a Manipulate objects that behaves like that famous möbius transform video. Since ...
1k views

### Non-commutative symbolic linear algebra

I am fairly new to Mathematica but I thought I would be a helpful tool to carry out a few simple linear algebra calculations. It seems like an easy task but I cannot figure out how to do it. For ...
1k views

394 views

### Nest , Fold … is there an extension for more than 2 arguments?

Fold is an extension of Nest for 2 arguments. How does one extend this concept to multiple arguments. Here is a trivial example: ...
719 views

Robert Raguet-Schofield in the Mathematica Blog introduced a way to import tweets from Twitter into Mathematica. I attempted to use this method. I started with this line of code: ...
294 views

### substitution rules excluding subscripted variables

Suppose I have an expression containing p,Subscript[p,1],Subscript[p,2],etc. I want to ...
2k views

### Simplify expressions with Log

How can I get Mathematica to simplify the following expression n Log[a] + m Log[b] - m Log[a + b] - n Log[a + b] into ...
3k views

### Complex number operations: telling Mathematica variables are real

I want to do Conjugate[a + b*I], but when I do that, the solution is Conjugate[a] - I*Conjugate[b]; when for me, a and b are ...
329 views

### Selectively clear DownValues

How can I clear a subset of a symbol's DownValues ? For example, suppose I have created some DownValues for $f$ like this: ...
306 views

### Find variable name from DumpSave on a scoped variable

I saved an InterpolationFunction in a ".mx" files using DumpSave on a variable that was scoped by a ...
1k views

### Pass list of options to Plot3D

Consider the example plotOptions = {PlotPoints -> 10, MaxRecursion -> 2} Plot3D[x y , {x, 0, 10}, {y, 0, 10}, plotOptions] Why does this causes the error: ...
266 views

### Antialiasing of horizontal lines

Consider the following graphic: g = Graphics[{Circle[], Table[Line[{{-1, i}, {1, i}}], {i, -1, 1, 0.2}]}, ImageSize -> 150] (You may need to look directly ...
160 views

### Substituting confidential tagged cells by a “content removed” cell

When producing a notebook with both code and text, I often end up with pieces of code, or even entire chapters, that I don't want to be shown on the final output. I generally hide or close them by ...
2k views

### Convert a string to hex number?

How can I convert a string containing a hex number such as "6b" to a hex digit that mathematica can use to do math with? I have tried using ...
5k views

### How to get rid of warnings when using Solve on an equation with inexact coefficients?

When I solve this equation in Mathematica 8, I can get the right answer, but with some uncomfortable warnings. Equation: ...
5k views

### Plotting Partial Sums of Fourier Series

I'd like to plot some partial sums for a Fourier Series problem, but I am not sure if the output I am getting is correct. I want to be able to plot the partial sums and the function on the same graph. ...
6k views

This is just a follow-up of this post: Beginner 2D animation with maths equations Part of the code is: ...
173 views

### How to make Inset graphics maintain relative sizes when combined

I am learning a little about Inset, but after trying all options, I can't get this to work. I need to inset separately made Graphics2D objects, into one main ...
549 views

### Solving $L=\frac{3}{2} \sqrt{4 \pi ^2 A^2+W^2}-\frac{\sqrt{5 W \sqrt{4 \pi ^2 A^2+W^2}+6 \pi ^2 A^2+3 W^2}}{\sqrt{2}}+\frac{3 W}{2}$ for $W$

When I solve the aforementioned equation for $W$ or $A$ on Mathematica I get a long and ugly equation in return, namely one of the solutions for $W$ is: (attempt to read at your own health) ...
1k views

### How to make a resizable chess board?

For some reason I need to create a chess board. I can create a chess board by following command: ...