# All Questions

3k views

### How to play with Facebook data inside Mathematica?

I saw this post from Wolfram here and I would like to know how to import facebook data into Mathematica.
444 views

### Launching remote kernels - will it help RAM needs?

Given the exasperating RAM needs of my Mathematica program, I contemplated launching remote kernels to run my Mathematica script. This is a two part question: Part 1 If I launch a remote kernel(s), ...
161 views

### Test First row of matrix

What is a good way to test the first row of a Matrix to check if one of the values equal a value. For instance, In this example, I want to get vector in the second row that has the bigger value in the ...
300 views

### How to improve this dynamic progress bar code

I created this progress bar to use in my codes: ...
2k views

### Factorisation diagrams

Here is a way to visualize the factorisation of natural numbers. How do we get this or a similar kind of output using Mathematica? See the list of images generated for number from 1 to 36:
286 views

### Modules that initialize themselves on first call

I use a lot of functions that extract a specific data item from a file with many data items. I want these functions to load data (slow) and return the item (fast) on first call, but just return the ...
1k views

### Get x and z coordinate from an image and make a parametric surface

In this blog entry, this step is mentioned: I grabbed an image of a Peugeot wine glass from the web and used the Get Coordinates function to digitize its outline, which I fed to Interpolation to ...
585 views

### Don't simplify an expression

I have an expression that I want Mathematica to fully expand without any simplification afterwards. I want the output to look like the following example. ...
140 views

### Intersection of conditions

If I have a list of conditions: {cond1,cond2,cond3} and I want to use an If[] statement to test the intersection of these ...
578 views

### ListPlot with Joined set to True

Let f[x_]=9x^2-2x-3; I want to make a table of f at x ={-1, -0.5, 0, 0.5, 1, 1.5, 2}. ...
899 views

### ColorFunction in Histogram[]

Let's say I have a Histogram: Histogram[RandomVariate[NormalDistribution[10, 2], 500]] and I want the bars positioned to ...
2k views

### Parameters in plot titles

My issue is how to mix strings with variables, specifically in the context of PlotLabel: I can put a string as my plot title, and I can also put a variable as a ...
573 views

### Dynamically remove element from list based on test

Suppose I have a list l = {a, b, c, d, e, f....} I would like to remove one of each pair {x,y} if some function ...
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 ...
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 ...
182 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 ...
230 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? ...
304 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 ...
528 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 ...
238 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: ...
60 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 ...
797 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 ...
357 views

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 ...
179 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 ...
906 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 ...
526 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 ...
304 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, ...
4k 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 ...
344 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 ...
2k 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: ...
459 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 ...
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 ...
619 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 ...
910 views

### What are some advanced uses for Block?

I read the answers to this question (What are the use cases for different scoping constructs?) and this one (Condition, Block, Module - which way is the most memory and computationally efficient?). ...
268 views

### Comparing 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 ...
159 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 ...
278 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 ...
540 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 ...
790 views

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

Consider the following code: ...
377 views

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

Using Palettes -> Writing Assistant -> Math Cells, you can enter aligned equations such as: ...
255 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 ...
162 views

### Confusing ReplaceRepeated & Hold

I've been bootstrapping myself to the very alien world of Mathematica and there came my first WTF moment: ...
7k 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 ...
208 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 ...
870 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: ...
103 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 ...
827 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?
478 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: ...