46
votes
6answers
2k views

How to abort on any message generated?

Mathematica is a bit unusual as a programming language because it never stops on messages, regardless of whether the message is an error, a warning or just an informative message. It simply prints the ...
40
votes
5answers
3k views

How to efficiently find positions of duplicates?

Is there an efficient way to find the positions of the duplicates in a list? I would like the positions grouped according to duplicated elements. For instance, given ...
52
votes
2answers
10k views

How can I use Mathematica's graph functions to cheat at Boggle?

Boggle is a word game played with 16 dice and a 4x4 tray. This question is inspired by a Stack Overflow question about Boggle that I decided to solve using Mathematica. In addition to Mathematica, I ...
38
votes
1answer
1k views

Transferring a large amount of data in parallel calculations

This question is inspired by one of @whuber's answers Consider the following code: ...
23
votes
5answers
4k views

Plotting several functions

I'd like to plot a function of one real and one integer variable, but I don't want them all shown in the same 2-D plot - I'd like to see them as separate curves so I can see both "axes", more like how ...
25
votes
5answers
1k views

How do you programatically load data into symbols?

I am trying to convert a list of string names into symbols, which will then be used to store data. I have 24 files (where the name of each file is a member of the list mentioned above) that I need to ...
15
votes
3answers
987 views

Problem with ParametricPlot

I'm plotting gear curves, and I observe that for some parameter values ParametricPlot[] does not plot all the teeth: ...
19
votes
2answers
2k 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 ...
36
votes
2answers
2k views

Is it possible to change the colors of the highlighted code in the Mathematica frontend?

With Format -> Edit Stylesheet... it is possible to adjust text-properties, text-colors, formatting of equations, etc of a notebook and to use this style-definitions again by installing it as ...
41
votes
3answers
5k views

Calling MATLAB from Mathematica

How can I call MATLAB functions directly from Mathematica and transfer data/variables between the two systems?
38
votes
5answers
4k views

Filling a polygon with a pattern of insets

I am trying to fill a shape with diagonal lines. I am aware of Texture, but it rasterizes the fill pattern, which is not desirable. Here was my crack at it: ...
40
votes
7answers
6k views

Intersecting graphics

Does the Mathematica graphics system have any concept of intersecting graphics? I've not found much in the documents so far. For example, if I want to show the intersection of two shapes: ...
33
votes
5answers
8k views

What is the most efficient way to add rows and columns to a matrix?

Say I have a matrix m and a vector v. ...
26
votes
3answers
8k 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 ...
37
votes
4answers
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 ...
32
votes
1answer
646 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 ...
20
votes
2answers
2k views

How do I perform string matching and replacements?

What are, and how do I use Mathematica's string matching and replacement tools?
6
votes
2answers
329 views

Question about MapThread and Dynamic

I don't understand the following: f[a_, b_] := a + b ls = {1, 2, 3}; MapThread[f, {ls, {10, 20, 30}}] This yields ( as expected ) {11,22,33} If I change ...
24
votes
4answers
10k 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. ...
43
votes
6answers
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 ...
38
votes
3answers
5k 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: ...
37
votes
7answers
4k views

Efficient way to generate random points with a predefined lower bound on their pairwise Euclidean distance

Using Mathematica what is an efficient way to generate a list of $n$ random two dimensional points $\{x_i,y_i\}$ where $i=1,...,n$ so that no two points $p_1$ and $p_2$ in the list has an Euclidean ...
25
votes
1answer
2k views

Why won't Parallelize speed up my code?

What reasons are there that can cause parallelized Mathematica code not to run with full performance?
22
votes
3answers
3k views

I'd like to display field lines for a point charge in 3 dimensions

I'd like to display field lines for a point charge in 3 dimensions. Not a force field (short arrows) but continuous field lines that start on the charge.
30
votes
1answer
941 views

How do you set attributes on SubValues?

SubValues, as discussed in a previous question, are declared as follows ...
21
votes
5answers
2k views

Having the derivative be an operator

How do I create an operator which acts like a derivative to everything to the right of it: for example: $ \left( \partial_x + \partial_y + z \right ) x \psi $ How do I make that evaluate to: $x ...
13
votes
7answers
3k 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 ...
10
votes
4answers
2k views

Problem with ContourPlot

I tried these ...
50
votes
2answers
3k views

Once more on object orientation in Mathematica: does it have to be so hard?

Recently I came across a set of problems which would be solved most easily within an object-oriented approach. I first attempted to solve them by other means, but found the complexity of the code ...
41
votes
5answers
6k views

How can I extract data points from a black and white image?

Consider the following graph (source): Is there any way to extract the data points from this image in a semi-automatic way? I have seen, and tried the methods suggested in this question, but they ...
48
votes
3answers
2k views

The clearest way to represent Mathematica's evaluation sequence

WReach has presented here a nice way to represent the Mathematica's evaluation sequence using OpenerView. It is much more clear way to go than using the standard ...
38
votes
2answers
3k views

An efficient circular arc primitive for Graphics3D

As many people have noted, the 2D graphics primitive Circle doesn't work in a Graphics3D environment (even in v10.0-v10.2, where ...
29
votes
8answers
2k views

Removing elements from a list which appear in another list

There are two lists {a, b, c, a, d, a, e} and {a, c, a}. I need to remove those elements from the first list which appears in a second list, to get {b, d, a, e}
36
votes
3answers
3k views

Saving Mathematica kernel state?

If I save a notebook, I only save what I see. That is, if I close Mathematica and reopen the notebook later, all previous calculations are lost, except for those things I've output. Now I know that ...
36
votes
2answers
2k views

Automating Esc [[ Esc formatting?

Is it possible to program the Front End to automatically format double square brackets without having to type Esc[[Esc each time? It's awful to have to type Esc ...
43
votes
4answers
3k views

Point Renderings Slightly Off in Mathematica

The Mathematica code ...
37
votes
3answers
2k views

Antialiasing in 3D

Is it possible? Is it platform specific? Does it rely on the graphics hardware? Why does the antialiasing slider under Preferences > Appearance > Graphics do nothing? I remember seeing some ...
29
votes
4answers
740 views

How to make MapAt work with Span?

Span (;;) is very useful, but doesn't work with a lot of functions. Given the following input ...
20
votes
7answers
2k views

Find continuous sequences inside a list

I have a list which is something like this: {3,4,5,6,7,10,11,12,15,16,17,19,20,21,22,23,24,42,43,44,45,46} What I'd like to to is get the intervals which are in ...
35
votes
1answer
626 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 ...
21
votes
4answers
6k views

Multivariable Taylor expansion does not work as expected

The basic multivariable Taylor expansion formula around a point is as follows: $$ f(\mathbf r + \mathbf a) = f(\mathbf r) + (\mathbf a \cdot \nabla )f(\mathbf r) + \frac{1}{2!}(\mathbf a \cdot ...
9
votes
2answers
2k views

How to make traditional output for derivatives

Hello again after some pause. i have a problem how to present partial derivatives in traditional form, not as Mathematica gave it to me in its notation. So I want to present this ...
18
votes
2answers
5k 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 ...
12
votes
2answers
9k views

How to specify assumptions before evaluation?

If I request mathematica evaluate an integral for me, I'll often get a more general ConditionalExpression than I want. Example : ...
8
votes
2answers
305 views

Unexpected behavior of rule matching a pattern

I am a beginner exploring the world of Mathematica. I expected the following code T[6, 5, 4, 1, 2, 3] /. {T[a___, 1, b___] -> Length[List[b]]} should return ...
498
votes
6answers
167k 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 ...
65
votes
4answers
2k views
55
votes
4answers
7k 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 ...
56
votes
6answers
2k views

V10's Operator Forms - what are they good for?

V10 introduces an operator form for several functions perhaps primarily due to their role in queries as part of introducing data science functionality. At first pass it seems a lot of effort to add ...
33
votes
5answers
8k views

How to perform a multi-peak fitting?

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3). The ...

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