# Tagged Questions

Questions on writing non-trivial programs in Mathematica. Do not use this tag for questions on plotting/graphics or for questions on doing mathematics with Mathematica, where the focus is more on the math than the program.

226 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 ...
135 views

### Implementing a back button (in CDF)

I have a rather large notebook, which contains a lot of hyperlinks to different parts of the notebook. Is it possible to make a back button (maybe as a docked cell button?) so that when a reader ...
108 views

### Rounding only reals in an expression containing, reals, integers and symbols

I am trying to make a function that would make rounding real numbers in an expression possibly consisting of real numbers, integer numbers and symbols. An example of such an expression is below: ...
239 views

### Counting a cardinality of a subset satisfying special property

Suppose that we have a set of 9 2-dimensional vectors $c$ by m=3; n=2; c=Tuples[Range[m],n]; We want to define a subset $S$ of vectors in $c$ by the following: ...
345 views

### Solve this equation symbolically

I am trying to solve the equation for the quantity r = y/x symbolically: 3/y^4 == 3/x^4 + a/(x + 2 y)^4 with the requirement that we need to perform the ...
113 views

### Avoiding unnecessary computations within loops

Consider the following data: test = RandomReal[{1, 2}, {10, 5, 3, 3}]; How can I do the following without the For loops, e.g. ...
261 views

### How to insert an expression in a Mathematica program?

I need to insert a very large expression in a Mathematica program. So I first Put[large expression,"file"] and then use Block[{}, Get["file"];...] to ...
90 views

### Is it possible to 'partially' protect a variabile? [closed]

Please, consider a variable initialized at the beginning of a program: $myVar = {}; Protect[$myVar]; and the only two functions allowed to change it: ...
172 views

### Help with calculating a complicated integral

Edit: The question is solved : )) Thank you for your attention ! I am sorry for mass questions, but the question bothers me a lot. So I would like to ask this question here. This problem arises when ...
82 views

### Should I Remove the initial symbols of Module?

Often we use Module to construct complicate function. Consider that Module create new vars every time we run the function, should I remove the initial values at the end of Module-function?Or should I ...
73 views

### Arrange order of evaluations (please help these unit vectors) [closed]

I need help to control order of evaluations. Here I try to use Manipulate to control n unit vectors. Their positions are initially random but head left. The 2 operations are 1) translation: moving ...
96 views

### Calling a custom function in slave kernel process connected through mathlink [closed]

I am performing a small experiment to check if we can call/execute a custom package function in slave kernel launched from master using mathLink. I have created a dummy application called ...
85 views

### How to use RunProcess to run python interpreter

In a related question How to use RunProcess to import external function? @taliesin provides a very nice answer illustrating using RunProcess to launch a GO http server. Has anyone, or does anyone ...
84 views

### Retrieve rendered graphics via WSTP

I am planning on using Mathematica as calculation and rendering backend for an application, i.e., call Mathematica via WSTP and use EvaluatePacket to have it ...
123 views

### Simulations using alternative initial conditions

With help from some of you guys here in this forum, I have developed the following code, which works perfectly. My questions are: how to automate the simulations with varying initial conditions. In ...
142 views

### Using FindMinimum with matrix input

I define the following function which spits out a number S when I feed it a dxd square matrix: ...
131 views

### Code turns dark blue after trying to run it [closed]

I have a large amount of data in my N-Body Code. I imagine Mathematica doesn't really like this, but is there any other reason for my code turning a navy blue colour after I try to run it?
88 views

### Updating procedural fitting algorithm to more efficient style?

For some time now, I have used this procedural programming approach to fit data in my research that is too cumbersome for the built in Mathematica functions. (Although this simple example works fine ...
63 views

### deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
51 views

### Settings to disable global scope

I am building a fairly large application in Mathematica, and globally scoped variables are causing issues. I would like globally scoped variables to be out-of-scope for my expressions, except by ...
131 views

### Finding Values of All Nine Constants in q-hypergeometric Equation

I suspect that an identity of the form $$\sum_{j=-n}^{j=n}(-1)^jq^{j(5j+1)/2}=\sum_{r=0}^{n}f_{ar+bn+c}(-1)^{n-r}q^{(n-r)(dr+en+f)/2}\frac{(q;q)_{gr+hn+j}}{(q;q)_{n-r}}$$ for $a, \dots , j$ integer ...
122 views

### Hide MathKernel Tab on Taskbar when using C++ [duplicate]

I am connecting to MathKernel.exe using C++ via MathLink on Windows. Hence, to create the link, this is what I use: ...
101 views

### Compiled version of user-defined function [closed]

I have a function for parameter estimation with these codes: ...
360 views

### Changing Default Color for Titles, Sections, Subsections, etc., and Items (bullet color) [duplicate]

I'm new to Mathematica 9, and I assume there must be an easy fix for my problem, but I have not been able to find any yet. Essentially, I want the default color for the text of all of my titles, ...
136 views

### Sum slowing down computations

I am trying to compute higher order Casimir invariants for some representations of certain groups. I can get the quadratic, cubic and quartic but beyond that things are taking too long to the point I ...
335 views

### Gram Schmidt inner and outer products

I know the Gram-Schmidt orthogonalization generates an orthonormal basis from an arbitrary basis. I need help with: Write a program that inputs a list $\{b_1,\dotsc,b_n\}$ of linearly independent ...
36 views

### How can I convert a list to an expression? [duplicate]

For example, I have the following list: {x1,op1,x2,op2,x3,op3,...} And I would like to convert the list to the following expression: x1 op1 x2 op2 x3 op3 ...
483 views

### Interpolating function as a model in Mathematica's procedures for fitting

Is it possible to use interpolating function with parameters as a model for NonLinearModelFit (and other integrated methods for fitting)? Similar question was ...
161 views

### Why doesn't ParallelMap improve the performance of FoldList?

This question arose during my analysis of the following problem: filling gaps. (The code used here is Simon Woods's work.) FoldList seems to not cooperate with ...
315 views

### Data structure for a list of actions [closed]

The idea: I need to generate a sequence of events then run a "propagator" over the list of events where the "propagator" will update the state of the following event. I can then write functions that ...
306 views

### Problem with function as an argument

I want to write a function like the following: s[u_, v_, x_, val_] := u[val]/NIntegrate[u'[x] v[x] + u'[x] v'[x], {x, 0, 1}] So I can evaluate something like ...
323 views

### Return Functions from parallel execution of module

I wrote a module which numerically solves an ODE using NDSolve. The result from this is e.g. either ...
706 views

### How can I fill in a matrix at every iteration of a Do loop?

I have a matrix whose dimensions are 26x26x3. For my assignment I have written a program which is using a Do loop (maxx=maxy=10,maxz=2): ...
134 views

### Plotting Graph of Zeno paradoxes

Zeno Paradoxes is about a Greek Heroes Archilles having a race with tortoise. the tortoise given a head start distance. Greek heroes Archilles have constant speed ...
207 views

### Avoid creation of OwnValues when inserting transformation rules into ExperimentalOptimizeExpression

I have a large list of transformation rules that I want to simplify. I find ExperimentalOptimizeExpression works as it gets me the answers. My question is: I ...
144 views

### How to avoid restart during development? [duplicate]

Possible Duplicate: How do I clear all user defined symbols? During package development things get messed up quite often. (especially when playing with notations) Is there a simple way to ...
86 views

### Do structures - listing iterated values

Please excuse the crudity / simplicity of this question, hbut I have never really got on too well with Do structures - perhaps I don't use them enough - perhaps I ...
98 views

### Diophantine and odd

need to resolve this Diophantine equation, but with the condition that a, b, c belong to the set of odd numbers from 1-51, as I write this condition in the code ...
184 views

### Problem with Maximize

As $\{p1,p2,p3,p4,p5\}$ represents a probability distribution and $l1,l2$ are the eigenvalues of a stochastic matrix, the function $f$, as defined below, has to be maximized over a certain region. ...
243 views

### Determinant of a random matrix consisting of integers

I am trying to implement a function that finds the determinant of a random matrix consisting of integers. This is the code I have written so far, but I am stuck. Suggestions ? I want to find a ...
66 views

### Calculating the angle between the line joining two points and the x-axis [closed]

I need to calculate the angle between two points, the returned result should between $0$ to $2π$ and getAngle[point1, point2]==getAngle[point2, point1]. I have ...
67 views

### Mathematica Code Involving For Loops Not Completing All Iterations [closed]

First of all, thank you for taking the time to read this. I'm working on a portion of code related to the genetic algorithm that is not producing the expected results. What the code is supposed to do ...
70 views

### How to output (anything) if any error happens

I have long code which goes through iteration process. some times I get error messages. I want to get the iteration numbers (or any kind of output indications) when errors happen. for example, how ...
126 views

### Where do those nulls come from? [closed]

I have seen discussions of unwanted nulls in the output in the context of building lists with conditions on the elements, but that is not involved here. I would like to know where the nulls come from ...
786 views

### Basic Dynamic Interface Programming that returns variables to nb functions

I have a dynamic module that contains some basic PopupMenu's and Buttons but also need to use the variables returned from these buttons and PopupMenu's in my nb functions outside of this ...
328 views

### Graphics copy paste

Background. I have a function ( stored in a package ) that creates 2D graphic images, its prototype looks like this: ...
275 views

### Symbol appears in multiple contexts when load two packages with unique function names

I have two packages "packageA" and "packageB". The function names across packageA and packageB are unique. No two functions have the same name. When I issue the ...
318 views

### Optimizing Chi-square distance between two distribution

I want to program the chi-square between two distribution Xu and Vu with length N. This function is defined as below: Xu and Vu are real and positive. ...
Something is wrong with my cobweb plot code but I couldn't figure out where do the mistakes come from. So basically we have the iterative map $x_n == x_{n-1}^{2} - 3 \mu$. I would like to draw a ...