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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1answer
153 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
227 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
64 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
66 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
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 ...
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2answers
760 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
306 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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1answer
204 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
270 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
114 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
712 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 ...
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2answers
78 views

How can i execute several Commands in one text file and use it in notebook?

I want to execute several commands in one text file and use it in notebook by Get[] command. for example: ...
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2answers
367 views

characteristic polynomial based on differential equation

I have this differential equation: $$\ddot{x}-\frac{1}{6} \dot{x} - \frac{1}{6}x = e^t$$ When I DSolve it looks like this: ...
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1answer
367 views

Finding resolution of an optical system using Rayleigh criterion

I want to use the Rayleigh criterion to find the resolution of an optical system. I have two functions f1 = Sinc[x]^2 and ...
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1answer
304 views

How can I improve my code with efficient mathematica built-in functions?

I have written a module for my assignment like below. V[n + 1] = rk[x[n], y[n] ,z[n], V[n]]; vs = V[n].V[n+1]; V[n + 1] = I want to modify it with efficient ...
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1answer
448 views

How can I make many runs of a simulation and plot all the results with one expression evaluation?

I have many cells, starting with this first cell: ...
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1answer
142 views

FE`symbols that remain in notebook internals even after removing them and SaveDefinitions->True issue

How does one clear the notebook from symbols that remain in it after an edit session?
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1answer
89 views

Import Tex's aligned multiline equation into Mathematica

I know there have been answers to similar questions, using either ImportString or ToExpression, however I haven't been able to succeed in importing this. I'm using version 10 Mathematica on Linux by ...
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1answer
58 views

How to implement the for loop to replace text strings or texts?

I wonder define a bunch variables named like $X_1$, $X_2$, $...$, $X_n$. Is there some smart way to declare them instead of by pure typing. One trick I can image is to use the for loop,...
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1answer
125 views

Iterating FindRoot to solve a differential equation

I am new to Mathematica style programming, better at traditional programming. I would like to know if I can create a table of results using FindRoot, where the ...
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1answer
83 views
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1answer
83 views

Functions behaving weirdly

The following code f[k_, n_] := Sum[2*(1 + Sum[f[k - j, n - m - j], {j, 1, k - 1}]), {m, 1, n - k + 1}] f[4, 7] f[4, n] gives the output: ...
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1answer
156 views

How do I find the nearest city out of a list of cities?

I am trying to find the next closest city to city 1 and want to use a certain radius to check what is the closest city I'm trying to create an algorithm for a TSP. Does anyone know how to implement ...
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1answer
66 views

Elegant ways of solving this file batching task

There are a batch of data files in a folder (dir = "D:\\Documents\\datadir"), each of which consists of a list of data items, one per line. Each data item is a pair ...
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1answer
90 views

How to plot multiple orbits with more than two functions

Using a program given to me (which was designed to have a particle orbiting another of infinite mass), I tried to extend it to the motion of two particles orbiting a common centre of mass. I have a ...
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1answer
662 views

Obtaining the envelope of an oscillating function and perform fitting

There is an elegant way to obtain the envelope of an oscillation function explained here http://mathematica.stackexchange.com/a/27854/15966 My question is how to modify the code below so I can fit ...
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1answer
112 views

ParallelTable not firing

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1answer
1k views

Getting imaginary data from known real data using Kramers-Kronig relations [duplicate]

Possible Duplicate: Kramers-Kronig in Mathematica I am trying to get epsilon2 (imaginary part) from known epsilon1 ...
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1answer
72 views

How can I calculate the root of any order of power series

How can I calculate the root of any order of power series with Mathematica. Here I insert every quantity by hand. But I want to give a, ...
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2answers
71 views

Flipping random elements in a matrix

I'm still a beginner with mathematica so maybe the solution is obvious, but for some reason my code that worked fine earlier doesn't work now. I haven't changed anything about it. I've restarted ...
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1answer
46 views

Results of a function are different when the function call and subsequent statements are evaluated one line at a time

I have some code that I am porting from VBA to Mathematica. The original code processes data on an Excel spreadsheet. In Mathematica, I find it convenient to replicate the Excel spreadsheet data ...
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1answer
177 views

Finding CPU time of more than one expressions

I want to find the computational time (CPU time) of my code. When I use TimeUsed or Timing commands they give the CPU time of ...
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1answer
205 views

Is it possible to build/simulate/extract data from a System Modeler model completely inside a notebook using the MathModelica language syntax?

See examples in: http://www.mathematica-journal.com/issue/v10i1/contents/MathModelicaPaper/MathModelicaPaper_2.html It seems to be ruled out by the statement (Chapter 2 intro): "The subset of the ...
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3answers
153 views
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1answer
283 views

Using Findroot within a loop

I am trying to get solution to an equation in a loop. The isolate equation works ...
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votes
1answer
137 views

How to save the results in an identical Excel file (.xls) in each iteration of a Do loop

Assume the following code (Below code is just an example to clearly illustrate my problem): ...
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1answer
136 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
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1answer
70 views

How to put some values from a list into a function in a Do loop

I want to program a code in MATHEMATICA in order to calculate some values in different iteration. For example, assume this list: list={1,2,3,4,5} Now assume that ...
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2answers
115 views

Finding lags of time series with `Do`

I have generated two time series, S[t] and P[t] as follows: ...
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1answer
80 views

How to write series of Do[ ]'s with a single Table[ ]?

Edited to provide more information (sorry I don't know how to format matrices here) I would like to replace: m = 4; ...
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1answer
147 views

Holding Input Windows

I am creating a Mathematica document which contains a list of proofs in various fields of Mathematics so that I can easily review whenever I would like. First, I create a large set I call 'proofs' ...
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1answer
227 views

How to combine two usages of # into one and speed up the code?

I have a function num with two variables, matf and matg. How can I combine the last two lines of code below into one? The code is aimed to find out the maxiaml count bel when we give each $i3 = ...
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1answer
222 views

Pattern match with Table for matrix dimension check

In Mathematica, often an expression involving matrices will encounter dimension mismatch errors, like we are multiplying a 3x2 matrix to a 3x4 matrix. Below we define a new symbol Dim, which can be ...
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1answer
235 views

Why does memory run out when adding same-sized matrices in a loop?

I have written a module that it generates a 101x101x51 zero matrix at first. At every iteration, it generates a list by funct1 and based on this list, if list is empty it gives the previous result. ...
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1answer
43 views

Solving simultaneous and determinant given constant value and variable T (temperature) [closed]

How to solve this two simultaneous equations? these two equations got from this free energy equation ...
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1answer
64 views

errors in simple for loops

Im trying to run the following code, which I have translated from Matlab. I created a for loop nested inside another for loop. mW is a matrix, and ...
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1answer
75 views

Mean squared displacement of a single trajectory

I have a single particle trajectory and would like to calculate the mean squared displacement. The particle is moving from blue over yellow, green to red data points. The {x,y} data are available ...
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votes
1answer
74 views

Formulate an equation to find a fixed point [closed]

I have the following equation: Subscript[x, n + 1] = Subscript[x, n]^2 + c with Subscript[x, 0] = 0. This equation is restricted ...
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1answer
63 views

How do I get the last three vectors to complete this cube?

Looking at this file, what vectors do I need to add to the cube:={...} in order to get a full cube?
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1answer
78 views