23
votes
2answers
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.
0
votes
2answers
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), ...
2
votes
5answers
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 ...
3
votes
1answer
300 views

How to improve this dynamic progress bar code

I created this progress bar to use in my codes: ...
35
votes
5answers
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:
12
votes
1answer
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 ...
16
votes
3answers
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 ...
3
votes
1answer
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. ...
2
votes
1answer
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 ...
2
votes
1answer
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}. ...
8
votes
2answers
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 ...
5
votes
3answers
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 ...
3
votes
2answers
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 ...
25
votes
4answers
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
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 ...
3
votes
1answer
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? ...
4
votes
2answers
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 ...
4
votes
2answers
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 ...
3
votes
0answers
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: ...
0
votes
0answers
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 ...
11
votes
2answers
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 ...
14
votes
1answer
357 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
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 ...
11
votes
1answer
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 ...
3
votes
4answers
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 ...
11
votes
2answers
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, ...
7
votes
2answers
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 ...
1
vote
1answer
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 ...
4
votes
1answer
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: ...
3
votes
2answers
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 ...
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
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 ...
21
votes
2answers
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?). ...
4
votes
2answers
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 ...
5
votes
2answers
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 ...
1
vote
1answer
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 ...
11
votes
6answers
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 ...
12
votes
3answers
790 views

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

Consider the following code: ...
7
votes
0answers
377 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
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 ...
4
votes
2answers
162 views

Confusing ReplaceRepeated & Hold

I've been bootstrapping myself to the very alien world of Mathematica and there came my first WTF moment: ...
30
votes
5answers
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 ...
2
votes
1answer
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 ...
0
votes
1answer
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: ...
1
vote
2answers
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 ...
3
votes
1answer
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?
1
vote
1answer
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: ...
0
votes
0answers
109 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
114 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++. ...

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