# All Questions

2k views

### Generating a broken or snipped axis in ListPlot

I have two data sets, data1 and data2. For example: ...
3k views

### How to avoid returning a Null if there is no “else” condition in an If contruct

I need to use If but with only one option that is if "a" then do "b", else do nothing. So I wrote If[a,b] but the problem is ...
2k views

### Does Mathematica support variable frame rate for any video format, in analogue of GIF-style “DisplayDurations”?

The good old GIF animation format allows us to set the duration of each individual frame in the animation separately. This is especially useful if some frames in ...
677 views

### Common subexpression from two expressions

I am working with some unpleasantly tedious polynomials, which need to be manipulated in various ways (integrate with respect to some variable, differentiate with respect to another). Since these ...
3k views

### Replacing composite variables by a single variable

To replace a single variable by another variable, one can simply use the the replace all (/.) operator (e.g., ...
1k views

### Usage of Assuming for Integration

For some reason, when I enter the following integration in Mathematica Assuming[{k ∈ Integers}, Integrate[ Exp[ I k t], {t, -π, π}]] the result turns out to be ...
1k views

### What is the difference between Set and SetDelayed?

I have a problem with defining a function and most of time I get confused by Set or = and ...
922 views

### Problem with ContourPlot

I tried these ...
1k views

### Using D to find a symbolic derivative

I need to do the following: Define a function Take the derivative of this function and have a look at the symoblic representation Substitute in some values With the bonus that I want to use the ...
4k views

### Minimal effort method for integrating C++ functions into Mathematica

As of Mathematica 8, what is the minimal effort way to integrate an existing C++ function into Mathematica? I think we have these: MathLink (it was quite long ago I used it last time) communication ...
7k views

### How can this confetti code be improved to include shadows and gravity?

Here's some confetti: ...
3k views

### Calling MATLAB from Mathematica

How can I call MATLAB functions directly from Mathematica and transfer data/variables between the two systems?
2k views

### Generating evenly spaced points on a curve

In the KnotData package a simple command such as points = Table[KnotData[{3, 1}, "SpaceCurve"][t], {t, 0, 2 Pi, 0.1}]; will ...
6k views

### How to calculate scalar curvature Ricci tensor and Christoffel symbols in Mathematica?

I am seeking a convenient and effective way to calculate such geometric quantities. I've used packages like TensoriaCalc, but they don't work at all time. ...
474 views

### How can I make threading more flexible?

Threading automatically with Listable functions requires the argument expressions to have the same length (or for one of them to be atomic). For nested lists the ...
396 views

### How can I get the unchanged Box form of an arbitrary expression?

One may observe that MakeBoxes does not give the actual Box form of various expressions: MakeBoxes[{1*^4, 000123, a*b c}] ...
477 views

### What can I use as the second argument to Return in my own functions?

Having found out about the second argument to Return I played a bit with it, and the following tests all resulted in ...
2k views

### how to differentiate formally?

I have been wrapping my head around this for a while now and I have not found a solution so far. I want to work with an arbitrary number of variables in mathematica and use some built in functions. ...
603 views

### How to inject an evaluated expression into a held expression? [duplicate]

I know that there are methods to structurally manipulate held expressions (discussed e.g. here), but I failed to apply those for this particular problem: ...
1k views

### How to load a package without naming conflicts?

This question applies to any package, but I encountered this problem while working with graphs. There are symbols in the Combinatorica package (such as ...
1k views

### How to pass a symbol name to a function with any of the Hold attributes?

Given a function with the attribute HoldFirst, HoldAll or similar, and a variable, list, how ...
4k views

### Can Reduce *really* not solve for x here?

Sometimes I get the feeling I'm just flailing blindly with Mathematica. Is solving for $x$ in the equation $$\frac{\cosh (x/2)}{x} = \sqrt{2}$$ really beyond the scope of Mathematica? I try to ...
5k views

### Recovering data points from an image

Unfortunately, some data can only be obtained in picture form (Japanese publications anyone?). Since this cannot be worked with, it has to be converted to a dataset that can; I was wondering whether ...
2k views

### Automatically generating a dependency graph of an arbitrary Mathematica function?

Has anyone written a function to pull the function dependencies of a function? That is, it would be nice to have a function that returns a list of function dependencies as a set of rules, terminating ...
2k views

### Point Renderings Slightly Off in Mathematica

The Mathematica code ...
3k views

### Extract current viewing parameters from a 3D view?

Is there a way to find out the current viewing parameters of a 3D view? What often happens is that I create a view, for example: ...
1k views

### Partition a set into subsets of size $k$

Given a set $\{a_1,a_2,\dots,a_{lk}\}$ and a positive integer $l$, how can I find all the partitions which includes subsets of size $l$ in Mathematica? For instance, given ...
745 views

### Resource management in Mathematica

I am using a library that has functions like createSomeObject[] and deleteSomeObject[obj]. It is an interface to a C language ...
748 views

### Prepend Information to Warning Messages

I have a function running within a Do loop that sometimes issues a warning. I'd like to prepend the warning with the loop ctr so that I can go back and debug that instance later. Basically, I would ...
2k views

### Aborting evaluation when the memory exceeds a certain limit

Sometimes when generating a lot of data the memory usage shoots beyond its physical realm and my laptop freezes. There is no way to stop Mathematica when this happens. Task manager (or its equivalent ...
4k views

### About multi-root search in Mathematica for transcendental equations

I have some questions for multiroot search for transcendental equations. Is there any clever solution to find all the roots for a transcendental equation in a specific range? Perhaps ...
3k views

### Is it possible to change the color of plot in Show?

For example: p = Plot[Sin[x], {x, 0, 1}] Is it possible to write options in Show to change the curve's color for example into ...
741 views

### How to get the real PlotRange using AbsoluteOptions?

The problem in general involves the unreliable behaviour of AbsoluteOptions when option values are implicitly specified (e.g. ...
769 views

### Optimising 2D binning code

I have a set of (x,y,z) data, 45,000 to be precise and I want to bin the z values in 256 equidistant bins based on their (x,y) values. The final array should be a set of 256x256 array with each slot ...
2k views

### Delete duplicate elements from a list

If a list contains duplicate elements, for example list = {a, 1, 5, 3, 5, x^2, x^2}, how can the duplicate elements be removed? The result would be ...
2k views

### extract values from replacement list

Solve returns a list of replacement rules In: Solve[x + y == 3 && x - y == 6, {x, y}] Out: {{x -> 9/2, y -> -(3/2)}} I am only interested in the ...
422 views

### Using Evaluate and Evaluated -> True in Plot

A few use cases: (1) This, as expected, returns (almost) immediately: f[x_?NumericQ] := Evaluate[(Pause[1]; x)] Plot[f[x], {x, 0, 1}] (2) This takes ...
1k views

### ParallelTable and Table do not give same result

I have a question regarding the use of Parallelize. In the help one can read that “Parallelize[Table[expr,iter, …]] (which is ...
361 views

### Help on evaluation control?

I want to plot series of slopes: x, 2x, 3x, 4x, 5x, 6x... I'm trying to do this: ...
158k views

### xkcd-style graphs

I received an email to which I wanted to respond with a xkcd-style graph, but I couldn't manage it. Everything I drew looked perfect, and I don't have enough command over ...
10k views

### $\LaTeX$ and Mathematica

I quite often would like to draw graphics in my $\LaTeX$ documents using Mathematica. I have encountered three problems. I would like to know if there are any workarounds to these problems I would ...
4k views

### Metaprogramming in Mathematica

Being functional, and having no "quotation", i.e. essentially treating data and programs semantically same, Mathematica seems naturally capable of doing metaprogramming. But could anyone construct a ...
2k views

### Profiling from Mathematica

I've always wished I could do some profiling like you get in Wolfram Workbench, but directly from Mathematica, without using or having Workbench. If it is possible, how can I do it?
5k views

### How to make a 3D globe?

There are many ways to create a 3D Earth that is rotatable (see here, here, related here), but most of them have some drawbacks. These issues mainly stem from either ...
4k views

### Torn edge paper effect for images

In my answers to Plotting Error Bars on a Log Scale I used a so called "torn edge" effect from on one of the images. @SjoerdC.deVries commented: "BTW I liked the ripped-out look of your InputForm ...
1k views

### How to plot ternary density plots?

How can I get a ternary density plot just like the plots from OriginLab? ContourPlot and DensityPlot seemingly can solve the ...
1k views

### Map a function across a list conditionally

It seems that this is a really basic question, and I feel that the answer should be obvious to me. However, I am not seeing. Can you please help me? Thanks. Suppose I have a list of data ...
901 views

### Can a Trie be implemented efficiently?

What is the most space and time efficient way to implement a Trie in Mathematica? Will it be practically faster than what is natively available in appropriate cases?