# All Questions

446 views

### Issues with ColorFunction Scaling when using RegionFunction in VectorPlot

I was plotting a VectorPlot and restricting it to the physically meaningful region using RegionFunction. To my surprise, the ...
356 views

### Solving a system of equations using subscripted variables

I want to solve this equation: X(i, j) + C*Y(i, j) = Z(i, j) Where ...
142 views

### Trouble with Replacements [duplicate]

I have the following line of code: Plus @@ Table[p[x], {x, 0, 20}] /. p[x_] -> Boole[MemberQ[{0, 5}, x]] The first part of this produces ...
817 views

### How can I efficiently write formatted data to a Gaussian Cube file?

I am working with data files that contain information about electronic wave functions. The data format is specified by the quantum chemistry program Gaussian. I need to import the data, manipulate ...
2k views

### Problem with ContourPlot

I tried these ...
381 views

### Including two ListLinePlots in a 3D graphic

I have two lists of data which I am plotting on two ListLinePlots. I would like to have these two plots appear perpendicular to each other on a 3D graphic. I have ...
193 views

### RSolve[{y[0] == y0, y[t + 1] == (1 - (t + 1)/100) y[t]}, y[t], t]

When I evaluate this code: RSolve[{y[0] == y0, y[t + 1] == (1 - (t + 1)/100) y[t]}, y[t], t] I get an RSolve::bvnul error. I don't understand why. Yet, if I ...
196 views

### Why does Integrate return a solution that is not defined at a particular point when it actually is well defined at that point?

I am trying to compute Integrate[Sqrt[x^4 + (y - y^2)^2], {x, 0, y}] Mathematica 8 gives ...
1k views

### How to program a F::argx message?

How useful is it to program a user-built function in a package to produce a red warning message F::argx if you give the wrong number of arguments to that function? ...
486 views

### substitution rules for Penrose tiles

This page on W|A shows a nice substitution rule to draw kites and darts. I'd like to implement the rule in Mathematica, so I've drawn the original kite and its replacement (separately). I've also ...
200 views

### diff-able text-only notebooks?

I would like to save my Mathematica notebooks as plain-text documents, so that I can keep them under git version control. I thought that ...
123 views

### How can I recover a graph from a graphical output in a notebook after resetting the kernel?

I have an old Mathematica notebook with an output for a graph structure $G$ I would like to recover. However, the routine for building up the graph is stochastic, so I can't simply rerun the code. ...
104 views

### given n lists, get list of applications of function to n-tuples

Is there a built in function or an easy rule to do the following transformation? H[{A[0], A[1], ...},{B[0], B[1], ...},...] into ...
665 views

### Assume function is real valued

I want to create a function returning subscripted symbols and I want these symbols to be assumed real. How do I do that? ...
843 views

### Do/For loop for plots

I have a lot of points that I would like to get shown on a plot. The problem is that sometimes I only have 2 points while other times i have 10 points. I've tried to make a for loop to create a plot ...
157 views

### How to apply tags to expression terms?

I often see on this site and at the mathgroup the repeated questions on how to rearrange expression that Mathematica "likes" to keep in one form, but the user prefers in another. Consider this trivial ...
273 views

### Making FindShortestPath a little bit sloppy [duplicate]

I have a dense graph, and I'd like to find multiple "almost shortest" paths from a source vertex, $v_s$, to a sink vertex, $v_s$, on an undirected graph $G$. How can I repeatedly run ...
885 views

### How can I speed up numerical integration of multidimensional integral?

I am numerically solving an integral equation that contains a double integral. I have managed to get a solution but it takes forever. I am wondering if there is a way to speed up numerical integration ...
782 views

### Simulating discrete time stochastic dynamic systems

What is the canonical way of simulating discrete time stochastic dynamical systems in Mathematica using the new functionality of Random processes? To take a concrete example, lets consider the ...
320 views

### integrating slightly complicated expression which includes Abs

I have been waiting for Mathematica to give me something for the following integral, errors welcome, but it has been "running" for almost 30 minutes now. ...
372 views

### Why is CityData[All, “Coordinates”] failing?

When I evaluate CityData[All, "Coordinates"] Mathematica returns {Missing["NotAvailable"], Missing["NotAvailable"]} ...
151 views

486 views

### Graphing time-series

I'm currently trying to use data gathered as a function of time (here, the fluorescence of a biological sample), but am new to Mathematica and don't know how to properly specify axis relations (and ...
1k views

### Is there a built in function to obtain the back diagonal of a matrix?

Given the following matrix: m = Array[Subscript[a, #, #2] &, {4, 4}] how can I find the skew diagonal or anti-diagonal or back diagonal of the matrix (...
178 views

### Request help for reading text data files with headers and 2 sections

I just started with Mathematica. I need it for many purposes, but the important one is to read a text data file and extract column values as variables. I have successfully tested the tab delimited ...
1k views

### Solve Differential equation system

I've tried to solve this differential equation system, buy without any luck. This is my code: ...
252 views

### Extracting the integers from a list

I have a list where the elements are Reals and Integers. How can I extract the Integer? For example, if I have {1, 2, 3.4, 9.9}, how can I get ...
124 views

### Help bogged down at first query [duplicate]

When I open help at the first time in a mathematica session and I submit a query it always get bogged down for many seconds until a message appears as in the picture. Then I select continue waiting, I ...