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.

learn more… | top users | synonyms

0
votes
3answers
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 ...
0
votes
1answer
191 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. <...
0
votes
3answers
245 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 ...
0
votes
1answer
79 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 ...
0
votes
1answer
68 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 ...
0
votes
2answers
71 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 ...
0
votes
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 ...
0
votes
2answers
787 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 DynamicModule....
0
votes
1answer
334 views

Graphics copy paste

Background. I have a function ( stored in a package ) that creates 2D graphic images, its prototype looks like this: ...
0
votes
1answer
290 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 ...
0
votes
1answer
329 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. ...
0
votes
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) ...
0
votes
1answer
817 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 ...
0
votes
2answers
81 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: ...
0
votes
2answers
405 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: ...
0
votes
1answer
397 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 ...
0
votes
1answer
324 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 ...
0
votes
1answer
482 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: ...
0
votes
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?
0
votes
1answer
54 views

FullForm and the attribute HoldAll

I have noticed that TrueQ @ (And @@ {False, True, True, True}) gives False and, on the contrary, ...
0
votes
1answer
103 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 ...
0
votes
1answer
77 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,...
0
votes
1answer
154 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 ...
0
votes
1answer
86 views
0
votes
1answer
222 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 ...
0
votes
1answer
69 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 ...
0
votes
1answer
92 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 ...
0
votes
1answer
741 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 ...
0
votes
1answer
117 views

ParallelTable not firing

...
0
votes
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 (real ...
0
votes
1answer
95 views

How to overload the operator “*” as KroneckerProduct [closed]

Can I use the expression below a * b * c * d for short to instead KroneckerProduct[a,b,c,d] automatically when a,b,c,d are ...
0
votes
1answer
37 views

Looping over a function with several parameters

Folks I am a beginner in Mathematica and have a simple question regarding loops: Here's the problem, I have a dataset of with four columns and I need to loop over each row. So the matrix in which my ...
0
votes
1answer
48 views

Experiment to test Infinite monkey theorem [closed]

I need to apply this experiment: For all numbers between [0,128] let be t {set total=0 repeat this experiment n times {set start=0 choose random number [0,255] lets be R While(R!=t) {...
0
votes
1answer
62 views

How to use Do and NestList combine?

g[x_]:=((i - 1/i)*x + (1/i)*(x/2))/2; I want to find the following list NumberForm[NestList[g, 0.8, 20], 16]; But don't ...
0
votes
1answer
29 views

How to select bottom three “norm” values and their corresponding matrices? [closed]

I calculated five random matrices of 6x3 (with some code which is already working) having name Subscript[randompop, j].Here is the output ...
0
votes
1answer
80 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, ...
0
votes
2answers
80 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 ...
0
votes
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 ...
0
votes
1answer
188 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 ...
0
votes
1answer
210 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 ...
0
votes
3answers
155 views
0
votes
1answer
336 views

Using Findroot within a loop

I am trying to get solution to an equation in a loop. The isolate equation works ...
0
votes
1answer
150 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): ...
0
votes
1answer
137 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
0
votes
1answer
74 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 ...
0
votes
2answers
116 views

Finding lags of time series with `Do`

I have generated two time series, S[t] and P[t] as follows: ...
0
votes
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; ...
0
votes
1answer
159 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' ...
0
votes
1answer
228 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 = 1,\...
0
votes
1answer
237 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 ...