# All Questions

135 views

### Colorize a 3D distribution of points according to density

Suppose we have some random 3D distribution of points. I'll use the spherical ball defined below as an example and a starting point for the discussion here : ...
308 views

### How to visualize slope fields of differential equations without vectors?

I'm looking to visualize slope fields of differential equations for my differential equations course. Every example I see draws them as vectors, adding unnecessary "arrows" that, to me, are visually ...
100 views

### A* algorithm for finding shortest path in a graph

FindShortestPath finds the shortest path between two vertices in an edge-weighted graph, allowing a choice between the Dijkstra and Bellman-Ford algorithms. In my (limited) understanding, both of ...
52 views

### Open a Mathematica 9 notebook in Mathematica 8

I have the following question: Can I open a Mathematica 9 notebook in Mathematica 8? Are there compatibility issues?
71 views

### How to increase processing speed? [closed]

Well, let's first begin with the specs of my computer: Win 8 i7-3537U CPU@2.00GHz 2.50GHz 4GB of RAM 64-Bit And using Mathematica 8 I have to create some programmes to solve statistical problems, and ...
46 views

### Can I make a function which depends on several arguments which are not independent?

Here's a simple example Suppose have the permanent relation that z is proportional to xy^2, for real numbers s. z = s x y^2 Now, we are interested in ...
58 views

### How to Solve/NSolve/Reduce this rationalized equation

In this problem I don't know why the system is not solvable. I have just one unknown K0. ...
41 views

### Simplify rearranges equations?

I've been using Simplify/FullSimplify to simplify some nasty equations, and by and large it does well but sometimes it rearranges equations in an unhelpful way. ...
51 views

### How to divide a notebook into sections? [closed]

I've seen some very nicely formatted Mathematica notebooks with sections, explanatory text, etc., but I can't figure out how to do something similar. The documentation is not especially helpful here ...
45 views

44 views

### Choose partition of a set with Manipulate

Suppose I have a set represented by an array of strings, like set = { "A", "B", "C", "D", "E", "F" } I would like to create a Manipulate which allows the user to build repartitions of the set. ...
36 views

### ContourListPlot not evaluating all of interpolated area

I am trying to plot a contour for a matrix, but it seems not to be evaluating all the points. Here is the interpolated figure, followed by the MatrixPlot version itself. I used this colormap because ...
32 views

### Slow evaluation of complicated Table

I have a system of recursive equations x[t+1]:=f[x[t],p[t-1],a[t],a[t-1]]; p[t+1]:=g[p[t],x[t-1],a[t],a[t-1]]; a[t+1]:=h[x[t],p[t],a[t],a[t-1]]; I want to ...
76 views

### How to handle keyboard events for unselected item in CDF?

How can I force the keyboard input to work for this cell without clicking on it after I evaluate or showing a blinking selection cursor? This is for running CDF games in a browser. ...
74 views

### Using NVIDIA 3D Shutter Glasses with Mathematica

Mathematica has great capabilities to display 3D Graphics rendered to the 2D screen. This should make it perfectly suited to use the Graphics3D system together with an NVIDIA Graphics card, a 3D ...
43 views

### Solving for a variable within a definite integral using FindRoot

I want to solve for P in this equation: Integrate[1/((P/(M*V)) - r*g - c*A*(V^2)*p/(2 M)), {V, 0, 26.82}] = s , where all constants are given except P. I've ...
60 views

### Playing around with “spherical k-ellispe” on the sphere surface [closed]

It the Spherical K-ellipse I am looking for. What I mean is something like this but just with the two red curve and the sphere, idealy play with 2 parameters(number of foci and angle of the cone ...
151 views

### Draw generalized k-ellipse using “the locus of points so that sum of the distances to the foci is constant” deffinition

My goal is to draw a family (for different distances) of 3-ellipse for equilateral set of foci. 3-ellipse definition is: "the locus of points so that sum of the distances to the three foci is ...
69 views

### Poincaré section for 3BP

I try to plot the Poincaré section for the 3BP i use the following code that works very well: ...
66 views

### RandomSample Bug?

I was using RandomSample with very skewed weights. I am asking for a random sample of 6 numbers 1 through 100 without replacement. In the screen shown, the weights for 1 through 6 are 100 000, with ...
45 views

### Optimise CPU-intensive list combining function

I have a list of numbers list1 from which I want to create another list (list2) consisting of only those numbers that are equal ...
63 views

### How to plot a decahedron with Mathematica?

I wrote Graphics3D[{Opacity[.9], FaceForm[Yellow], PolyhedronData["Dipyramid", "Faces"]}] and I get this picture: I would like to plot a decahedron without ...
39 views

### Type Vietnamese in Mathematica

I type Vietnamese using UTF-8 Encoding but Text Display got error. How to type Vietnamese, Chinese in Mathematica. Please help me.
94 views

### Gather lists according to another list

I have a first list of pairs like this one: ...
52 views

### Plotting the discrete solution to a PDE

So I went through all the grunt work of solving a PDE in discrete form for a research project. Now I have a Temperature solution as a function of time and space:  T_{i}^{n+1}=\left( \dfrac ...
21 views

### Set Image Size and Page Orientation When Exporting to PDF

I want to export my plots (plot1 and plot2) as a pdf file. Since plot1 contains 4 figures in matrix form, so it will not fit in one page. ...
44 views

### Variance/Standard Deviation with a Constant Vaule

When applying variance (Variance[10]) or standard deviation (StandardDeviation[10]) to a constant value in Mathematica, Should ...
35 views

### Find the coefficients of a set of expressions in partial-derivatives [closed]

Is there a way to find the coefficients of these (terms within the square brackets) expressions using mathematica? \begin{align} \hat{l}^2=&\sum\limits_{a=1}^{4}\left[\left(\frac{\partial ...
38 views

### NDSolve::ndsz:At t==0.000039576, step size is effectively zero

I adjusted my code accordinly to the advice I got. However I still have a problem with this code which now looks like this: ...
43 views

### Why has my syntax coloring changed?

Local variables in Module are no longer specially colored for me, but other syntax coloring remains, for example iterators in a ...
30 views

### Generating the set of all three-dimensional binary arrays distinct under rotation and reflection?

How can I automatically generate all possible three-dimensional binary arrays of size $(x_1 \times x_2 \times x_3$) where each array is distinct from all others with respect to rotation and reflection ...
114 views

### Parallel optimization of Markov Chain Monte Carlo

I'm trying to reduce the computation time of a MCMC simulation. Essentially I have a set of particles performing a random walk in a periodic random potential. The particles are independent and every ...
243 views

### Why is this parallel evaluation with Dispatch[] so slow?

Can you efficiently parallelize this? The parallel versions are much slower than the sequential version, and I'm not sure why. Does SetSharedVariable allow ...
22 views

### Derivative with respect to certain variable. [closed]

How would anyone calculate this derivative using mathmatica?? More specific with respect to dln(alfa)
852 views

### Best way to extract values from a list of rules?

Mathematica has a lot of list manipulation functions, and, also because I don't work with lists often, at times I'm a bit lost. I'll find a way, but I'm sure it's not the most efficient. Case in ...
130 views

### Generating high quality charts in Mathematica for use in LaTeX and Word

I frequently have a probelem using my charts in reports because the text (axes labels and tick marks) look low resolution (fuzzy). When I export my charts, i export them as PNG files. Unless I'm ...
40 views

### Generalizing Characters to n-character substrings

I'm doing some frequency analysis on an encrypted plaintext. Tally[] and Characters[] make the basic task quite easy. To count the number of times each character appears (sorted alphabetically; ...
Does Mathematica have a function, similar to the one called coneplot in MatLAB? Given some spatial coordinates $x, y, z$ and velocity components $v_x,v_y,v_z$, it ...