21
votes
3answers
2k views

How to generate a random tree?

Is it possible to generate a random tree without explicitly constructing a random adjacency matrix that satisfies tree properties? How about a random directed tree? Edit: incredible answer by ...
3
votes
1answer
1k views

Improving NDSolve speed for heavily stiff problems

Having looked around the intergoogles and Mathematica.SE, I thought I'd pose a question with a minimum working example. Here is the situation I am trying to improve: I am solving a 4th order non ...
4
votes
1answer
166 views

What BarChart Option controls Joined line thickness?

Is there a named option that controls the thickness of the line segments that appear in BarChart with options ...
3
votes
1answer
214 views

How to partition MatrixPlot graphics?

Is there an easy approach - hopefully built-in - to partitioning MatrixPlot graphics into rows or columns (or both) of graphics sharing the same underlying options? ...
3
votes
2answers
278 views

Plotting two functions with dependent input function

I have defined a function: myJ2[n_] := 1/n* Total[RandomVariate[NormalDistribution[0, 1], n]^2] This is basically an approximation to the gaussian integral. I ...
4
votes
2answers
462 views

Loop and do operations on Matrix, then graph the results

I'm trying to do some operations to a matrix in a loop, and then I want to graph the results. The results are pair of numbers. Can I store the results of each iteration on "something" and the use ...
3
votes
0answers
231 views

Scale plot display area (within the frame)

I have 2 data sets of equal length. I've done a LinearModelFit of them which gives me: ...
0
votes
0answers
55 views

Make PlotMarker explanation [duplicate]

Possible Duplicate: Creating legends for plots with multiple lines? I have a ListPlot of data points. To distinguish between datapoints coming from different sources, I give them different ...
10
votes
2answers
681 views

How to vary color of fill between listplots based on y-distance between them

I have two lists with the same x-values but different y-values. I have used ListPlot to plot and fill the space (line) between them; however, I would like the color ...
14
votes
1answer
329 views

Why do Arrowheads interfere with ImagePadding?

Bug still present in version 10 under Windows. In a recent posting, Belisarius solved a problem related to the display of arrows on the x and y axes by setting ...
1
vote
1answer
150 views

Skip one step of the loop if there is an NIntegrate::eincr message

Is there a possibility of skipping one step of a loop if in this step there appears an error like NIntegrate::eincr? After skipping, the loop should go to the next ...
11
votes
1answer
725 views

How could I add arrows to the axis of a figure?

It is easy for me to add arrows to the axes of the a figure by taking advantage of AxesStyle -> Arrowheads[] when the differences between the horizontal and ...
3
votes
4answers
519 views

Faster code for specific problem

Sorry, but I need the following code much faster and I'm running out of ideas. I do appreciate any help. I post two of my fastest ideas (tab and mat), although they are not really fast. Thanks in ...
0
votes
1answer
349 views

singularity in NDSolve and Table command [closed]

We are considering the following equations ...
11
votes
2answers
265 views

Package found with `Needs`, but not with `ParallelNeeds`

I want to use a self-written package in a parallel computation. However while Needs["mypackage`"] works without problems, ...
3
votes
2answers
3k views

Integral equation numerical solution with NDSolve

I'm trying to solve something like: f[x] == Integrate[f[x]*g[x]] where g[x] is known and ...
1
vote
1answer
301 views

How to change the values dynamically in a grid

I am trying to write a function which creates a Grid which has no value in the starting and when some value is passed to it, it should show that value in that ...
4
votes
1answer
1k views

NonlinearModelFit::cvmit: Failed to converge to the requested accuracy or precision within 100 iterations

I have got a problem in my program with NonlinearModelFit: ...
2
votes
2answers
424 views

Total Variation Distance of probability matrix

How can I calculate the Total Variation Distance of a transition Matrix? is there any built in function? I've searched all documentation and haven;t found anything. ** More information: Let me try ...
17
votes
4answers
2k views

Spherical density plot of data set

I have a somewhat large number of 3-dimensional unit vectors ( ~ 100 000 unit vectors), and I am trying to visualize their distribution. First thing I tried was ...
2
votes
1answer
530 views

Linear Solve with Modular Arithmetic

I am interested in using LinearSolve[m,b] which will find a solution to the equation $m.x=b$, where I am in mod 2 arithmetic. Is there any way to perform this ...
19
votes
2answers
745 views

What are some advanced uses for Block?

I read the answer to this question and this one. According to those, Block is safer (if something aborts, it restores the values) and faster (perhaps something to ...
3
votes
2answers
244 views

LetL and Module efficiency

I was recently introduced to the LetL macro thanks to Leonid's answer to one of my prior questions. I was, needless to say, impressed by the simplicity of its ...
5
votes
2answers
150 views

How to silence all messages associated with a built-in symbol?

The post title's pretty much says it all... The reminder of this post just describes the little headway I made with this problem, FWIW. One would hope that ...
1
vote
1answer
262 views

Manipulate indexed Interpolating Functions

MWE I have some data indexed by gamma. For each gamma I want to find the intersection points of two lists and plot the lists ...
11
votes
6answers
511 views

Overlapping Red and Green ArrayPlots to show yellow intersections

Let's say I have two ArrayPlot[]s. One is in redscale and the other is in greenscale, such that the lowest value is white and the highest value is pure red or ...
12
votes
3answers
701 views

How to get 2D graphics into 3D without background?

Consider the following code: ...
7
votes
0answers
368 views

How can I export aligned equations to $\LaTeX$?

Using Palettes -> Writing Assistant -> Math Cells, you can enter aligned equations such as: ...
4
votes
2answers
238 views

Transform x-scale of data for e.g. MatrixPlot

I have to transform in a nonlinear way the x-scale of some data for a MatrixPlot (or ReliefImage or ...
4
votes
2answers
148 views

Confusing ReplaceRepeated & Hold

I've been bootstrapping myself to the very alien world of Mathematica and there came my first WTF moment: ...
29
votes
5answers
6k views

Custom arrow shaft

Inspired by Sjoerd C. de Vries' nice answer to this question, and the desire to pimp a Graph I did with Mathematica recently I would like to know if there are ways to customize the arrow's shaft ...
2
votes
1answer
189 views

Numerical comparisons of matrices

I have a matrix which should be equal to a null matrix. However due to the numerical precision, a brutal equality test with a matrix initialized with zeros does not work. How should I perform the ...
-1
votes
1answer
678 views

Help to solve Simultaneous Equations

I think this should be easy to numerically solve in Mathematica, but for some reason I'm not finding the correct way to do it. I basically want to solve these simyltaneous equiations: ...
1
vote
2answers
102 views

NSum generates a warning message when getting the sum of a list

I know what I'm doing can be done with Total: a = Range@3; Total@a And if I simply choose ...
3
votes
1answer
686 views

stationary distribution of a transition matrix

How can I solve the stationary distribution of a finite Markov Chain? In other words, how can I estimate the eigenvectors of a transition matrix?
1
vote
1answer
412 views

How do I make my discrete plot thicker?

I am making a discrete plot and a regular function plot together. But my curve is so thick that for color-blind people, it's pretty much impossible to see the black dots of my discrete plot: ...
0
votes
0answers
93 views

Good Introduction / Tutorial to Mathematica **Books** [duplicate]

Possible Duplicate: Where can I find examples of good Mathematica programming practice? I'm a high school senior and am using Mathematica for a research project. However, I find it a bit ...
3
votes
1answer
107 views

How to give ClusteringComponents initial values?

I came across a variant of k-means that adds a algorithm to select good starting values called k-means++. ...
17
votes
1answer
2k views

Vectorizing an image like “Trace Bitmap” in Inkscape

Lately, we had a nice question about artistic image vectorization which got very nice answers. As Szabolcs pointed out himself Since "true" vectorization performed by various specialized software ...
14
votes
1answer
503 views

Simulating Stochastic Processes the MMA way

This question is really a specific problem and a methodological one concerning MMA best practices. I want to simulate a system of stochastic processes. If this were a geometric Brownian motion or ...
2
votes
1answer
196 views

Getting the 557th element of a table

Make a table with elements $\sin(\sqrt{8 n}/4) + r\, $for $n$ from $1$ to $1000$, where $r$ is a random real number between $-0.1$ and $0.1$ that is different for each value of $n$. Also make a ...
9
votes
2answers
853 views

Using J/Link to decode Google Maps Polyline strings

I would like to use this java code inside Mathematica using J/Link. It converts Google Maps API Encoded Polylines to a list of points. I tried the Mathematica tutorial but got lost. There is the Java ...
12
votes
2answers
450 views

Proper Filling of Self-Intersecting Polygon

I have a spiral pattern that I would like to fill, which self-intersects. My desired behavior is to have filling between neighboring lines only, and to represent this figure as a single polygon. The ...
2
votes
1answer
427 views

How draw dynamic empty rectangle over a bitmap?

I am trying to make a cookie cutter that will extract a small square from a much larger bitmap with a click of the mouse. The LocatorPane appears to be a useful way ...
1
vote
2answers
236 views

Saving graphics object in order to manipulate it later?

I've generated a bunch of graphics using ContourPlot wich, given the nature of my problem, take a long time to create, and I was wondering if there is a way to save ...
9
votes
1answer
329 views

BUGS-type calculations in Mathematica

Recently I have been teaching myself how to Bayesian calculations with the BUGS language (JAGS, in particular). However, I find myself wondering how one might use Mathematica to do similar ...
4
votes
2answers
426 views

Split string into sub-strings of length n [duplicate]

Possible Duplicate: Partition string into chunks How can I split a string into sub strings of length n? For example I have a string "ABCDEabcde1234" ...
2
votes
2answers
505 views

Superscript prime symbol

x\[Prime] looks like $x_'$, ugly right? Is there a way to make a symbol with prime to look like $x'$? That's what I'm trying right now: ...
5
votes
1answer
1k views

Mathematica won't give eigenvectors but Wolfram Alpha will? What am I doing wrong?

If I ask Mathematica to find the eigenvectors and eigenvalues of the matrix: ...
9
votes
1answer
197 views

Ranking Function Allowing for Ties

I have a list that I need to be able to assign ranks to individual elements in, giving it a number related to its position if the list were to be sorted, allowing for ties. For example, ...

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