23
votes
1answer
11k views

Is it possible to export the equations from Mathematica to MATLAB?

Is it possible to export the output expressions from Mathematica computations (e.g., equations) in valid MATLAB syntax?
23
votes
3answers
1k views

“Covering up” text in Graphics

Consider the following code: ...
19
votes
2answers
10k views

How to make Jacobian automatically in Mathematica

If we have two vectors, a and b, how can I make Jacobian matrix automatically in Mathematica? $$ a=\left( \begin{array}{c} \text{x1}^3+2\text{x2}^2 \\ 3\text{x1}^4+7\text{x2} \end{array} ...
19
votes
5answers
3k 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 ...
19
votes
1answer
437 views

Shorter syntax for Fold and FoldList?

I find it tedious to write out the following: a = {1, 2, 3, 4}; Fold[f, First @ a, Rest @ a] f[f[f[1, 2], 3], 4] It ...
11
votes
2answers
5k views

What does # mean in Mathematica?

I asked Mathematica to compute the following Solve[c (1-x)^2-x^(1/4) == 0, x] and it returned this: x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 ...
10
votes
3answers
4k views

Given a Table of Plots with some parameter, how would I mark each of the plots with that parameter

I've got a two variable function that I'm plotting against one axis for a few different values of a parameter ...
25
votes
2answers
807 views

Block attributes of Equal

I answered “Equating matrices (or higher order tensors) element-wise” with: ...
14
votes
4answers
656 views

Returning an unevaluated expression with values substituted in

Let's say I have a function formula[x_List] := (x[[1]] - x[[2]]) + (x[[3]] - x[[4]]); and I want to pass it a variable and get back the unevaluated formula with ...
21
votes
2answers
470 views

Copying one symbol into another

I would like to know how can I completely copy one Symbol to another. When I say copy, a refer to UpValues, DownValues, ...
17
votes
3answers
2k views

Way to improve “show me this decimal number to M places, don't use scientific notation”?

The best way I can come up with to say "show me this fraction as a decimal number to M places, don't use scientific notation" is: ...
17
votes
9answers
1k views

How do you check if there are any equal arguments(even sublist) in a list?

I would like to set up a function which has to return True if at least two arguments of a given List are equal. So if I give {1,4,6,2} to the function it has to ...
13
votes
8answers
797 views

How to Map a subset of list elements to a function?

How would you, given a list {1, 2, 3, 4}, apply a function f to 1 and ...
9
votes
1answer
3k views

Plot, extract data to a file

I need to save data that Mathematica uses inside the Plot command. The format that I would like to have is: x1 y1 x2 y2 ..... ...
8
votes
5answers
3k views
8
votes
3answers
2k views

First positive root

Simple question but problem with NSolve. I need help how to extract first positive root? For example: ...
13
votes
2answers
1k views

How to extract the numerical value of a dynamical variable

I want to inspect interactively an image by selecting points by the mouse pointer. This is easily done by LocatorPane - here is a simplified example: ...
5
votes
1answer
294 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 ...
19
votes
8answers
664 views

Applying And to lists of Booleans

I'd like to take {True,True,False} and {True,False,False} and apply And to get ...
13
votes
1answer
1k views

Plot showing discontinuity where it shouldn't

I was trying to integrate a continuous function with a kink and I did it two ways and both ways the plot of the result shows a discontinuity. I also later want to differentiate the Integrated ...
12
votes
3answers
2k views

RevolutionPlot3D: but NOT revolving about the z axis

I want to demonstrate generating a solid of revolution by revolving a planar region about, say, a horizontal axis. However, RevolutionPlot3D doesn't seem to have an ...
11
votes
1answer
2k views

Combined numerical minimization and maximization

I want to numerically calculate the maximum of a function defined by the minimization of another function, like the following: ...
10
votes
2answers
623 views

Why does Integrate declare a convergent integral divergent?

When I try this command Integrate[1/Sqrt[(s^2 - u)^2 - 1], {s, m, Infinity}, Assumptions -> u > 2 && m > 10] Mathematica declares that the ...
9
votes
2answers
962 views

Automatically load packages at startup

I'm a physics student and I try to simplify my day with Mathematica. Every time I use Mathematica I need Div[], Grad[], ...
12
votes
3answers
1k views

Why is ContourPlot not displaying this curve?

I am using the general form of a second-degree plane curve: $$Ax^2+2Bxy + Cy^2+2Dx + 2Ey + F = 0$$ I want to randomly generate plane curves of this form, so I am using ...
8
votes
2answers
361 views

Why do I have to put Evaluate[] here

I wanted to draw some contours. I succeeded with this: ...
6
votes
2answers
248 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 ...
6
votes
2answers
823 views

Solve an equation in $\mathbb{R}^+$

How can I solve this equation (both numerically and literally) only in the positive reals $\mathbb{R}^+$? Solve[x == (v0 - (A CD t v0^2 ρ)/(4m)) Cos[θ] t, t] And ...
7
votes
2answers
1k views

Create complicated text formulas in graphics

I want to put somewhat complicated, or at least non-standardly formatted, text on some of my graphics. For example, I'd like to be able to use f^[4](x) (where the ...
4
votes
3answers
352 views

How can I compare a dynamic variable with a literal in Mathematica?

I'm doing a Mathematica Notebook and I want to make an alarm clock. Something like this: ...
52
votes
4answers
1k views
33
votes
6answers
2k views

How to visualize/edit a big matrix as a table?

Is it possible to visualize/edit a big matrix as a table ? I often end up exporting/copying big tables to Excel for seeing them, but I would prefer to stay in Mathematica and have a similar view as in ...
23
votes
2answers
4k views

What are the possible ways of visualizing a 4D function in Mathematica?

I have a function $F$ that maps the xyz space to a set of reals, more clearly: $c = F[x,y,z]$ Where $c$,$x$,$y$ and $z$ are reals. What are the possible ways of visualizing this 3d function in ...
39
votes
3answers
1k 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 ...
32
votes
5answers
3k views

Are there any cases when For[] loops are reasonable?

To my mind the only reason for the existence of For[] loops in Mathematica is to allow new users with some experience in procedural programming languages to write ...
31
votes
3answers
3k views

Data Table Manipulation in Mathematica

I am a statistician searching for an efficient way to select rows or columns from a table of data in Mathematica. Let me pose the question in 2 parts with a SQL-style table of data: ...
27
votes
7answers
2k views

Simpler input for the new unit support

I've been playing with the new unit support in Mathematica 9. It seems very useful, but the syntax is very verbose. Instead of typing: ...
26
votes
5answers
1k views

What is the complete list of valid Front End Tokens?

What is the complete list of valid Front End Tokens? Preferably, by version number. Keywords: FrontEndToken, ...
29
votes
6answers
2k views

Extruding along a path

I'm trying to render a 3D image of a path by extruding a circular cross-section along the path, creating a "snake-like" path. Here is an image I found to illustrate: I can't seem to figure out if ...
32
votes
1answer
1k views

Local variables in Module leak into the Global context

From the Mathematica documentation on Module: Module allows you to set up local variables with names that are local to the module. But after using ...
16
votes
5answers
811 views

Iterate until condition is met

I want to find the first 5 prime numbers of the form $n^6 + 1091$. I have used this code: Timing[Select[Table[n^6 + 1091, {n, 10000}], PrimeQ, 5]] Which gives ...
23
votes
4answers
1k views

Scale Insetted Characters to Plot

I am trying to place a curly brace within a plot such that the top/bottom of the curly brace line up with two horizontal lines in the plot: I have not been able to find a way to make the curly ...
17
votes
4answers
3k views

How to get intersection values from a parametric graph?

I have this graphed: ParametricPlot[{2.4*Cos[t] + 1.6*Cos[3 t/2], 2.4*Sin[t] - 1.6 Sin[3 t/2]}, {t, 0, 4*Pi}] It is a star, and the lines cross each other ...
20
votes
4answers
1k views

How to collect result continuously (interruptible calculation) when running parallel calculations?

This is the most common pattern to compute a table of results: Table[function[p], {p, parameters}] (regardless of how it's implemented, it could be a ...
22
votes
2answers
4k views

How to enter matrices in block matrix format?

Example: I have a matrix $R = \left( \begin{array}{cc} A & \mathbf{t} \\ 0 & 1 \end{array} \right) $ where $A$ is 3-by-3 and $\mathbf{t}$ is 3 by 1. Or in Mathematica ...
13
votes
3answers
604 views

How to program a F::argx message?

How useful is it to program a user-built function in a package to produce a red warning message F::argx if you give the wrong number of arguments to that function? ...
28
votes
2answers
1k views

Transpose uneven lists

Is there a quick method to transpose uneven lists without conditionals? With: Drop[Table[q, {10}], #] & /@ Range[10] Thus the first list would have the ...
23
votes
3answers
558 views

How to flush machine underflows to zero and prevent conversion to arbitrary precision?

I'm working on some pretty intense computation in Mathematica; when my code started running slowly, I tracked the source of the problem to Exp[]. I need to ...
27
votes
1answer
639 views

Prefix operator with low precedence

The question is simple, but I will elaborate on the background as well for those interested in the idea: How to define a new operator with specified precedence value? Background Mathematica was ...
15
votes
3answers
3k views

Solving a Volterra integral equation numerically

I would like to solve for $P(t)$, in Mathematica, a Volterra integral equation of the 2nd kind. It is: $$P(t) = R_0(t) + \int_0^t P(t') R_0(t-t')dt'$$ I know the function $R_0$ and would ...

15 30 50 per page