# All Questions

674 views

### Stop Computation - Is Exit[] overkill?

The following example either finds a factor of the number $n$ or returns a message saying that the number in question is prime (I specifially wrote this to demonstrate my question below). ...
273 views

### VariationalD giving the wrong solution?

EDIT: As pointed out in the comments, VariationalD gives a variational derivative (which I don't want), not a derivative with respect to a function (i.e. ...
233 views

### Creating event handler with ImplementJavaInterface inside a package

I am trying to make my Mathematica function to serve as an event handler for the events generated by a Java object. Specifically, I have a Java object that connects as a client to a server that ...
292 views

### Need an efficient method for finding certain matrices

I am trying to write a function which produces square matrices with certain characteristics. The function should have two inputs: number of the rows, n number of ...
298 views

### Why is my rasterized graphic blank?

Bug introduced in 7.0 or earlier, and persisting through 10.1 or later (OSX 10.10.2) Consider the following code: ...
1k views

### How can I get better control over StreamPlot?

I'm having some difficulties with the command StreamPlot in Mathematica 7.0. Here's the basic plots I'm doing : ...
678 views

### RSolve Lotka-Volterra: A Closed Form Solution to this Difference Equation?

I would like to solve a difference equation, a Lotka-Volterra difference equation. I tried a model from http://www.stolaf.edu/people/mckelvey/envision.dir/nonDE.lotka-volt.html Using their ...
253 views

### Fast integration of 2D distribution across lines parallel to y-axis

I'm struggling with a small data set and a slow calculation. I have hundreds of small 2D data arrays and need to integrate across several lines parallel to the y-axis. Let me start with the data ...
211 views

### Coarse-graining and/or sorting of a list of arbitrary triades {x,y,z} in the (x,y) plane [duplicate]

In general my question is related to an approach to make an interpolation of a data which is not on a regular mesh. Another aspect of this question has already been discussed after my question ...
139 views

### Composition with Apply

Composition is sometimes useful for clarity of a code. For the same purpose I try to Apply(@@) functions as often as it is ...
262 views

### Efficiently initialize list of consecutively named variables for file import

Let's say I have the code: ...
137 views

### Efficient Generation of Subgraphs (or, unfriend a friend a day)

NB: If you're not interested in the back-story, you could simply jump forward to the code which I'm seeking to optimize. Also, I believe this code would only work for MMA 8.0 and above. My friends ...
265 views

### Solving $(-1-z)^n = z$, for $z$ in the unit circle

I want to solve the following equation: $$(-1-z)^n = z,\quad |z|<1,\quad n>1\in \mathbb{N}$$ where $z$ is a complex number. However Solve or ...
422 views

### How to push the data from database?

I want to push the data from database to Mathematica application instead of application(MM App) pull the data.I have installed ms sql server and apache tomcat server. I have my application in apache ...
783 views

290 views

### RegionPlot3D Error

I have the following command: RegionPlot3D[ Log[p1/(1 + p2)] > 0, {p1, 0, 0.5}, {p2, 0.5, 1}, {C, 0, 1}] and my Mathematica 9 gave me the following error ...
207 views

### problem with exporting transparent object to pdf in version 9

Here is the code: Export["~/Downloads/1234.pdf", Graphics3D[{Lighter[Black], Opacity[0.5], Polygon@Table[{Cos[x], Sin[x], 0}, {x, 0, 2 \[Pi], 0.01}]}]] in ...
1k views

### Does Mathematica have a command analogous to ode45 of MATLAB?

Does anybody know if Mathematica has an analogue of MATLAB's ode45 command? I need to solve a second order coupled ODE system of equations.
89 views

### How to make rules for changing parameters

I have one boring problem with changing parameters in printing output. If I have equation ...
724 views

### Sort list by day names (Monday, Tuesday, etc)

I have some dates in a list, and I want to plot how many of those dates are Monday, Tuesday, etc. I'm using this: data = {...} Tally[DayOfWeek /@ data] and I ...
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418 views

### Transcendental equation inside another equation when 3D plotting

I have been trying to solve this plotting problem myself, and I have received a lot of very useful advice from here on Stack Exchange - but I am now at a complete loss as to how to achieve the plot I ...
191 views

### Simulations with MonteCarlo and Autoregressive methods

I am trying to find the best-fit trend for my data. Here I just generated it but let's say I don't know my data trend at all. ...
282 views

### Displaying a locator that moves smoothly and updates some dynamic variables

I want to select a point on a graph and display a function of the coordinates value. Asking here a related question I learned to use Setting. Consider the example, where I display the coordinate ...
680 views

### Plotting a network or a graph with given coordinates for vertices

I'm new to Mathematica yet have coded a lot in MATLAB. Currently I'm working on a network simulation. My model is implemented in MATLAB, but I need to port it to Mathematica. Here is my question: ...
147 views

### Can you label an array by variables or strings instead of integers?

Is there a way to label an array by a variable instead of an integer? For example calling the array I[i,j] with {i,j} = {x,y,z} ...
40 views

### Nested For Loops that result in no output [duplicate]

I am sure that this is not the most elegant code you will have seen, but I am trying to loop through an expression to see if FultonHarrisn] produces any outputs ...
197 views

### Output to preserve dot product

I am fairly new to Mathematica and I am faced with a problem. I tried to search for the solution but it seems that I don't know how to formulate the short search request. I need to perform a matrix ...
392 views

### ListDensityPlot performance when scaling axes

I need to visualize 3D data having 200*200 data points. ListDensityPlot is a good candidate, but it seems to have strange performance issues. I created a small ...
5k views

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603 views

### RecurrenceTable with a recurrence function of two variables

I have to calculate the cool down process of a regenerative heat exchanger. I solved the problem in Excel before, but now I want to do it with Mathematica. I want to create a table with the variables ...
1k views

### Writing data to a common file during parallel processing

I am executing a loop, and in each loop I have to store a parameter in a file. It is like ...
137 views

### Graphics updating from inside double-Fold-iteration within Manipulate

Normally, when using Manipulate[expr, controls, options], the graphics updating should be carried out at the very end of expr. But now I encounter a situation ...