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.

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2answers
148 views

Avoid making repeated Random Integer in different iterations

Assume following code : Do[ i1 = RandomInteger[{1, 5}]; i2 = RandomInteger[{1, 5}]; While[i1 == i2, i2 = RandomInteger[{1, 5}]] , {k, 1, 4}];` This ...
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1answer
222 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 ...
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1answer
122 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 ...
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1answer
103 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: ...
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2answers
179 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: ...
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1answer
253 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 ...
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1answer
106 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. ...
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2answers
246 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 ...
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0answers
78 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 ...
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0answers
64 views

Arrange order of evaluations (please help these unit vectors)

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 ...
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0answers
122 views

How can I launch kernels in series using mathlink

I have written below code to launch n kernels connected to one another in series using mathlinks. Before you read the code allow me to be more precise what i want to achieve: Source kernel(k1) ...
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0answers
62 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 ...
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0answers
69 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 ...
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0answers
105 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 ...
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1answer
124 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: ...
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0answers
97 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?
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0answers
78 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 ...
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0answers
77 views

Elementwise operation, part deux [closed]

There are many answers to this question: which are forms of Mathematica's map, but languages like Scheme (I think also Python in recent years) also provide a ...
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0answers
60 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}}; ...
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0answers
46 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 ...
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0answers
123 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 ...
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1answer
93 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: ...
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0answers
101 views

DifferentialEvolution scaling factor randomization

Using NMinimize for finding global minima, one can choose the DifferentialEvolution method. You can find a (not so) detailed ...
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0answers
93 views

Compiled version of user-defined function

I have a function for parameter estimation with these codes: ...
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2answers
281 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, ...
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0answers
122 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 ...
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1answer
283 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 ...
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0answers
34 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 ...
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0answers
154 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 ...
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0answers
286 views

Data structure for a list of actions

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 ...
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1answer
261 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 ...
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0answers
282 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 ...
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3answers
533 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): ...
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3answers
163 views

Avoid creation of OwnValues when inserting transformation rules into Experimental`OptimizeExpression

I have a large list of transformation rules that I want to simplify. I find Experimental`OptimizeExpression works as it gets me the answers. My question is: **I can only get this to work when I ...
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2answers
133 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 ...
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1answer
80 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 ...
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3answers
91 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 ...
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1answer
116 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. ...
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3answers
208 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 ...
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1answer
57 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 ...
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2answers
63 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 ...
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1answer
125 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 ...
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2answers
732 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 ...
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1answer
276 views

Graphics copy paste

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

FindShortestTour to solve Traveling Salesman Problem

I'm trying to write my own code to find the shortest route but I'm lost on how or where to start. Does anyone have any idea how the FindShortestTour function works? What type of algorithm or structure ...
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1answer
93 views

InterpolatingFunction used to work with mathematic 7 but not working with mathematica 10

This code is used to work perfectly with Mathematica 7 and now it is not working with Mathematica 10. Any help is appreciated. CL05 = InterpolatingFunction[{{0.5, 11.99999999999999}}, {1, ...
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1answer
114 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 ...
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1answer
206 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. ...
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1answer
113 views

Conditioning on group of functions

I have two sets of functions which I want to implement them in a single function with an option indicating which set of functions should be used. Suppose that I have two lists like:(updated example) ...
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1answer
615 views

What is wrong with this Cobweb plot [closed]

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 ...