4
votes
1answer
301 views

Drawing partition diagrams on spheres

I will be doing a few presentations at an undergraduate research conference later, the topics of which are somewhat tentative at the moment, but one of the things I wanted to go over were some of the ...
2
votes
2answers
287 views

Preparing data for making an ErrorListPlot

I often have the following notebook in Mathematica, which I use to make a dataset and associated errors: ...
2
votes
1answer
110 views

Replace an expression with a slightly tricky LHS transformation

I would like to make the substitution x^(11*y) -> r in the following equation x^(11 *y^z) - 1 to end up with: ...
1
vote
3answers
357 views

Convert coefficients of polynomials into a matrix

I have several sets of 5 polynomials of the form: ...
1
vote
1answer
69 views

How can I use list processing functions on data in a file?

How might I work with the following functions on a list, if the list is a disk based file? Partition[] DeleteDuplicates[] Split[] SortBy[] The file is too ...
6
votes
1answer
90 views

How can I get the style of selected cells?

How can I get the style such as Input, Text, Code, etc., of a selected cell? If a group of cells is selected, how can I get styles of all the cells in the group?
5
votes
0answers
99 views

Expansion of $E(i c \mid m)$ at $c\to\infty$?

Currently, I am using a Windows machine with Mathematica 8. I noticed a difference in a series expansion of the function EllipticE[] in comparison with a result ...
3
votes
2answers
90 views

How to generate a list from an iterator and some arbitrary function

Suppose I'd like to generate a table of integers: Table[i, {i, 10}] Great; now suppose I want only the integers that are even ...
3
votes
2answers
270 views

Colors associated to parts of a 3D distribution of points

Suppose we have a long list of random points (cartesian coordinates) in 3D space. coords := ...; Until now, I was associating colors in a radial way, from the ...
0
votes
1answer
120 views

Problem with displayed coordinates in LogLinearPlot

I have a very weird problem that I don't usually get. I try to plot a set of equations using LogLinearPlot and the Get coordinates right-click menuitem is working ...
2
votes
1answer
92 views

How to relate setter buttons with equations

I want to relate or connect a setter bar with a set of equations to graph them. ...
0
votes
2answers
272 views

Expansion in Basis Functions

I am trying to create an expansion of the form f[x,y]->Sum[Cn[x] y^n,{n,1,order}] To replace the function f by the ...
6
votes
4answers
630 views

How to apply a function to a list of tuples

trialList = {{0, 24.701}, {1, 24.69}, {2, 24.733}}; f[x_] := x + 1; I would like to apply the function f to only the second ...
5
votes
1answer
168 views

Why does this pattern for combining two lists require triple underscores (___) to work?

I understand that __ is a list of one or more elements, and that ___ is 0 or more elements, but when I try this rule with 2 ...
4
votes
1answer
416 views

Efficient method for inverting a block tridiagonal matrix

Is there a better method to invert a large block tridiagonal Hermitian block matrix, other than treating it as a ordinary matrix? For example: ...
2
votes
2answers
4k views

Make a scatter plot from two lists

I have two lists of values xx = {0.1, 0.3, 0.35, 0.57, 0.88, 1.0} yy = {1.2, 3.5, 4.5, 7.8, 9.0, 12.2} I want to make a scatter plot (list plot) with xx as x ...
1
vote
1answer
75 views

Asymptotic expansion of a list

I am trying to calculate a asymptotic series expansion of a list. ...
0
votes
2answers
396 views

How can I suppress message “… cannot be used as function”?

I'd really appreciate your help. The code gives me a solution, but in the end it says it cannot be used as function, which is not true. Script: ...
0
votes
1answer
118 views

How can I impose a condition on Solve or FullSimplify?

I would like to define a real 3-D vector as, say, v = {x, y, z}, but I want it to have a fixed norm and not necessarily a unit norm. I would like to impose this ...
2
votes
3answers
166 views

Manipulate fails with f[x]=x^k/(1+x^k)

I have this code: Clear[f] f = Function[x, x^k/(1 + x^k)]; Manipulate[Plot[f[x], {x, 0, 5}], {k, 1, 10}] But nothing draws as I move the slider. Am I missing ...
19
votes
1answer
485 views

Why are there two separate MathKernel processes running when I start up Mathematica 9?

When I start the Mathematica 9 Front End, and check the list of running processes, I see two separate MathKernel processes. If I only start the kernel, without a front end, then there's only one ...
3
votes
1answer
557 views

Join a piecewise plot

I wrote some code to get a piecewise plot which is displayed correctly. Now I'd like to join the various parts of the plot, using some kind of interpolation, to get a continuous chart even though it's ...
0
votes
0answers
50 views

Mathematica: How to apply a function to a list of tuples [duplicate]

trialList = {{0, 24.701}, {1, 24.69}, {2, 24.733}}; f[x_] = x + 1 I would like to apply the function f(x) to only the second element of each tuple. How is this ...
18
votes
3answers
2k views

Fastest way to calculate matrix of pairwise distances

It is a very common problem that given a distance function $d(p_1,p_2)$ and a set of points pts, we need to construct a matrix ...
1
vote
2answers
163 views

Solve f'[x]==0 for x

I tried the following: f[x_] := x^n/(k + x^(2 n)); Solve[f'[x] == 0, x] But I got the following response: Solve::nsmet: This system cannot be solved with the ...
0
votes
1answer
161 views

Solving a differential equation for a variable in a function

This may sound like a very trivial question, but I need to solve a differential equation as follows: ...
0
votes
2answers
440 views

Simplifying a trigonometric equation to obtain specific terms

When I try to solve the non-homogeneous differential equation ...
7
votes
2answers
408 views

How to generate a matrix group?

I have three $7\times 7$ matrices (with real entries, lots of zeros) and I'd like to check if they generate a finite group (or, more precisely, if the group they generate is of precise order). Would ...
2
votes
1answer
124 views

How to extract the bin width from a Histogram made with an automatic binning method?

I am using the Scott binning method with Histogram and Histogram3D to plot some data. How could I find out the bin width chosen ...
0
votes
1answer
588 views

Steady states and eigenvalues for a non-linear system:

I am trying to understand a non-linear system of equations, and find their steady states and dynamics. I am noob to understanding Mathematica (I am using version 6, but I have access to the latest ...
8
votes
3answers
944 views

Convex hull of a 3D object?

I am trying to find a convex hull command for a Graphics3D object. Does it exist in Mathematica? ...
14
votes
1answer
155 views

Standard message definition construct

Why are the messages almost always defined like this (at least in packages): If[Not@ValueQ[function::usage], function::usage = "Usage message"] and not just like ...
3
votes
1answer
101 views

Reading RData files without RLink

I am using Mathematica 8. I would like to read some RData files which I have received. I do not currently have an installation of R on the machine with Mathematica.
10
votes
4answers
293 views

How to pass a list of arguments into HoldAll

I have a list of arguments (which in reality is lengthy): arguments = {a, b, c} arguments2 = {a_, b_, c_} f[Sequence@@arguments2] := a + b + c Note: It seems ...
1
vote
1answer
233 views

Evaluate Notebook from .Net

How is it possible to send the whole content of an existing notebook to Mathematica for evaluation by using NetLink/C#?
9
votes
2answers
153 views

Can anyone explain this strange behavior of InputForm?

In Mathematica 9.0.0, when to display the input form of two numbers, I come across maybe a puny problem. In order to focus on the problem, I will put up a simplified version. ...
3
votes
1answer
915 views

Methods for NonlinearModelFit

I am using NonlinearModelFit for a thesis project. I get quite different results if I change the Method to LevenbergMarquardt or QuasiNewton or ConjugateGradient ...
5
votes
1answer
96 views

What happened with the file?

What happened with this file? infile = "\\test data.txt"; outstr = OpenWrite[infile]; instr = OpenRead[infile]; Read[instr, Record]; Close[instr]; All ...
7
votes
5answers
352 views

Efficiently finding the positions of a large list of targets in another, even larger list

I have a big list. It contains nearly 60,000 sub-lists. It's structured like bigList = {{x1,y1,z1},{x2,y2,z2},{x3,y3,z3},.....,{x60000,y60000,z60000}}; I have ...
4
votes
1answer
186 views

ContourPlot from Vector Data

I have data in the form of x, y, vx, vy where vx and vy are components of the velocity vector at point x,y. I want to plot a contourplot of this. How can I do that since contourplot asks for three ...
16
votes
4answers
528 views

Clustering a set of points

I have a set of 2D points in the square defined by {-1, -1} and {1, 1}. These points typically form compact groups. I need to ...
3
votes
0answers
323 views

How to make 3D object smooth?

This thread considers mathematical methods here to make the 3D object smooth but this question consider how to achieve the goal of smoothing a 3D object in Mathematica. I want to get smoother ...
12
votes
1answer
105 views

Is there a callback for notebook exit?

I know that $Epilog is called when Mathematica is exited; is there a callback upon exiting the notebook? If so, what is it?
0
votes
2answers
265 views

Creating an API or Widget based on a Mathematica notebook

I'm trying to create a matrix calculator and graph tools for our website and was wondering if there is a way to create Wolfram API or Widgets based on a Mathematica notebook.
4
votes
1answer
312 views

How do I set the boundaries of the legend for a ListDensityPlot?

I have a 3-d array imported from a text file. One dimension represents time, and the other two represent space. It's basically an array of 2-d arrays of temperature values. I want to plot these values ...
11
votes
5answers
334 views

Faster way to convert triangle list to edge list with no duplicates

I have a list of triangles returned by a Delaunay triangulator, in the following format: ...
1
vote
3answers
322 views

How to revolve a surface about a line other than the $x,y,z$ axes? [duplicate]

I just started working with Mathematica 8 and I'm having trouble revolving a function the way I want. I have to revolve the function $x^2/4 +2$ and $y= 0$ around $y=6$ to form an ashtray, but I ...
3
votes
1answer
668 views

Manipulate (Linux version of Mathematica)

I'm runnning Mathematica 9 on Ubuntu 11.10. After installing CDF player I still have problem (most of time) with Manipulate. Only way I'm able to change value of a ...
5
votes
2answers
208 views

Update a function avoiding infinite recursion

I am quite new to Mathematica and not completely familiar with functional programming. I am currently working with a function (call it foo) and wish to change its behaviour, for example, by adding 1 ...
3
votes
2answers
453 views

Evaluating the integral of $\cos (\theta )\cos\left[\tan ^{-1}\left(\frac{a^2 \tan (\phi )}{b^2}\right)\right]$

I am trying to evalute the following integral: Integrate[Cos[θ] Cos[ArcTan[a^2/b^2 Tan[φ]]], {φ, 0, 2π}] I know that for $a=b$ I should get 0 out of the integral ...

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