# All Questions

354 views

### How can I get Mathematica to recognize equality of symbolic matrix expressions?

I have two matrix expressions: X.Transpose[T].Transpose[X] and X.T.Transpose[X] I want Mathematica to recognize that ...
440 views

### Cropping a Voronoi diagram

Someone know how can I get the correct crop of this Voronoi image using RegionFunction? As you can see, there is a lot of undesired white regions inside the left ...
130 views

### Trouble carrying out symbolic operations on matrixes

I have some problems. First of all, I declare matrices like below ...
247 views

### How to annotate a Grid?

I have the following grid, which is a partial table for the linear function f[x]: ...
125 views

### Pattern Matching with Indexed Object

If I have a list of rules associated with indexed variables like: solution = {a[1] -> 1, a[2] -> 10, a[3] -> 100} I would like to be able to extract all ...
380 views

### Compile recursive function modifying global variables

How to compile recursive formula when it relies on more than a few global variables (global to the topmost compiled function)? It is unreasonable to pass on all such variables to each recursive ...
563 views

### Failing to import an .eps file

I have an .eps file which was created using GLE. There is nothing wrong with the file, GS View can read it correctly. However, when I use Mathematica to read it using ...
539 views

### Resolution problem of ContourPlot

I met a tricky problem with ContourPlot, which is when I change the range of my variable, I get a totally new figure. For example: ...
704 views

### How to generate 2D FEM mesh in Mathematica?

To generate 3D mesh TetGen can be easily used. Are there similar functions (or a way to use TetGen) to generate 2d mesh? I know that such functionality can be easily implemented but I would like to ...
271 views

### Collect and simplify both the coefficents and the matched patterns

(This is a far tighter version of a previous question I asked) The problem with Collect is that while Collect[exp, pattern, Simplify] will simplify the ...
221 views

### What's wrong with my code for finding primes?

From here I found a fast method to make prime list, the python version works well, but my Mathematica version does not. Obviously ,169 is not a prime number. What's ...
541 views

### Changing the background color of one element in a Grid

Consider the following code: Grid[Table[x, {4}, {7}], Background -> {4 -> LightRed}] This highlights column 4: ...
496 views

### Finding central point in a ContourPlot

I am using ContourPlot for defining a 2-parameter space feasibility of a function. This function simply returns 1 if everything is ...
45 views

### Running PlotLegends in Mathematica 8 [duplicate]

I will like to get a density plot (in Mathematica 8) as in: Make legend same height as plot. However, anytime I run ...
423 views

### SinglePredictionBands versus MeanPredictionBands from NonlinearModelFit

From my Statistics lectures I know the term confidence and prediction interval, whereas the confidence interval is smaller than the prediction interval. If I plot the mean and single prediction bands ...
337 views

### Simplifying expressions involving Sum

I am trying to use Mathematica to simplify a symbolic expression involving Sum. Particularly, I define a sum via ...
241 views

### How do I interpolate a set of points with colour varying along the curve?

I have a table with 3 columns - x position, y-position and colour. I'd like to plot these points and join them with line segments, where the colour of the line segment is determined by 3rd variable. ...
1k views

### How do I show the combined plot from the do-loop?

I have a do-loop to do the calculations from a set of data and plot the graphs with different results, that was obtained from the calculations. I was able to get multiple graphs but I want to ListPlot ...
968 views

### How can I produce multiple column data for export?

I have data produced by the following code: ...
220 views

### Map a function conditional on elements at multiple relative positions in a list

I figure this question has many solutions, and if an answer already exists it would be nice just to be referred to it. I need a function that 'maps' over my list and produces a list of equal length ...
122 views

I have been using some basic MathLink programming in my work and wanted to create some more sophisticated MathLink programs. I came across the book "MathLink: Network Programming with Mathematica", ...
579 views

### How can I draw a grid behind graphics without using Plot?

I want to a show simple vector summation but I don't know how to draw a grid behind the vectors. I am pretty sure I can do it with Mathematica but how? It should look like this:
265 views

### How to parallel this nested table efficiently?

I have an 8 core CPU and want to parallel evaluate the following nested Table Table[Table[expr[i,j], {i,1,10}], {j,1,4}] But ...
94 views

### ConditionalExpression Limiting Domain

I came across a problem when evaluating the following integral: $\int_0^t \sqrt{9 x^4+1} \, dx$ Now, when I evaluate that, I get ...
705 views

### UNIX time to DateList

I have data that is timestamped with UNIX time, which is the number of seconds since January 1, 1970 UTC. Unfortunately, it seems that most of the date and time functions in Mathematica are based on ...
98 views

### How can we use RowReduce with a modulous AND variables?

We can use RowReduce with a field. For example, we state RowReduce[{{1,3,5},{0,1,2}},Modulous->23] ...which then returns: ...
517 views

### Need help with exception handling

I have read the docs for Catch, Throw, and friends multiple times, and I confess that I find them utterly incomprehensible... ...
185 views

### New integration symbol

Is there a way to introduce a new integration symbol? Specifically I want to be able to use ⨍. I have no problem entering it into mm, but the size does not change like the standard \int does.
565 views

### Only final result from NDSolve

Finally I started to play with differential equations in Mathematica. And I have faced the problem, which seems too me so basic that I'm afraid this question is going to be closed soon. However, ...
481 views

### Plot basins of attraction using separatrices for particular pendulum

How can I plot the stable and unstable separatrices to make a graphic of the basins of attraction of this differential equation? ...
438 views

### Use output of NDSolve as an integration limit of NIntegrate

I've been working on a ODE, for a function y[t], that, due to it's complexity, has to be solved numerically. I then need to use the results of NDSolve, which I ...
205 views

### Improving the performance of a package for working with rational functions

As Mathematica gets slow for large symbolic calculations, the cost of putting terms over a common denominator (Together), in particular, gets too high. It occurred ...
268 views

### Why does the evaluation of this series fail?

The following series expression holds: ...
297 views

### How to construct this matrix fast?

I write a function which is a matrix as below: ...
110 views

### Replace !x with x != 1

I have some logical relationships that I ultimately want to pass to NMaximize as constraints: ...
343 views

### Transform recursion for coefficients into differential equation for generating function

Assume, one is given a linear recursion with polynomial coefficients for a sequence $(a_i)_i$, such as a[i] == i a[i-1] I would like to convert this recursion ...
308 views

### Can someone explain this code for joining two lists by the first element of each sublist?

Background (which may be skipped, unless context is needed) I've recently begun learning Mathematica (and only up to chapter 3 of Wellin), but wanted to write some code to get a better feel for ...
58 views

### Determine appropriate initial conditions for exit time

These are some constants: ...
127 views

### Detect when InputField gets keyboard focus

How might I detect when an InputField comes into focus? For example ideally something like this would work. ...
308 views

### is there a method to send different cell evaluation to different core

I am running Mathematica on a computer with mulicpu and every cpu has multicore. I am wondering if there exist a method to send different cell evaluation to different core? So if I already have a ...
2k views

### Problem with NonlinearModelFit: “The function value… is not a list of real numbers…”

I'm trying to use NonlinearModelFit to fit the data: ...
62 views

### Errors in evalauting an expression

I have the following: Constants: b3b = 2; G = (1/eps^2); a1 = 3; a3 = 4; xc = 0.3; Functions: ...
208 views

### Revert Notebook to earlier version using Notebook History

Is it possible to revert a notebook to its earlier version via the Mathematica's Notebook History panel? It would be nice if I could select a point in time in the bottom graph and revert back to that ...
918 views

### Debugging with Breakpoints

re: Version 9. I typically write concise code and make a real effort to refactor. As such debugging has tended to take care of itself. Recently, I've needed to assemble applications of more ...
780 views

### Writing to file as it goes [duplicate]

I was wondering if there was a way to write data to a file, during a Do loop, without having to wait till the end. I have written a code which scans over many parameters which get plugged into many ...
438 views

### How can I make a list plot with bars?

Can anyone help me please? I don't want a Histogram; I don't want a BarChart, not even a ListPlot with drop down lines. I want a list plot with drop down columns/bars: please see the link. It is ...
266 views

### How to prevent Grid from breaking the line upon export

I want to create a legend for my plots (a mixture of RegionPlots and ContourPlots). The legend should show the meanins of colors as boxes with text in them and the meaning of contours as framed number ...
240 views

### How can I break through Function's HoldAll attribute to force evaluation of a body element?

The question concerns creating a function. Let consider the following code With[{f = Function[t, Cos[t]]}, {First[#], f'[#]} & ] which returns ...