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
237 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
252 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
458 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
119 views

Why is my funtion is wrong? [duplicate]

My aim is to know whether the data has same element. ...
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3answers
151 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 ...
0
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1answer
139 views

Differences between 'Solve' and 'LinearSolve' [closed]

Using the function 'Solve' I can do the following: Solve[a x + y == 7 && b x - y == 1, {x, y}] I get the following output: I want to get the same output using 'LinearSolve' instead. How ...
0
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2answers
131 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 ...
0
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1answer
92 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
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3answers
194 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
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3answers
142 views

How can I use NestWhileList instead of While in this case?

OK, the problem occurred when I challenged with Project Euler No. 10 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. My code is: ...
0
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1answer
90 views

Problem with Label in a Do loop, “nolabel” [closed]

Can someone tell me why this code doesn't work and how to fix it ? Thanks. ...
0
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1answer
122 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
676 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 ...
0
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1answer
243 views

Graphics copy paste

Background. I have a function ( stored in a package ) that creates 2D graphic images, its prototype looks like this: ...
0
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1answer
81 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, ...
0
votes
1answer
51 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
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1answer
116 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
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2answers
55 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
112 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
504 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
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2answers
72 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
260 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
607 views

Find Roots in Do loop

Task: Finding roots in loop t = List[1, 2, 3, 4, 5] fx[x_] := a*x^2 - 5 List[Do[Print[FindRoot[fx[k] == 1, {a, 1}]], {k, 0, 5}]] Output: Currently the output is ...
0
votes
1answer
264 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
349 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
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1answer
83 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
2answers
122 views

Are there ways to create local variables analogous to a local variable in C++ and other languages? [closed]

There has been a great deal of discussion on local variables in Modules and Manipulate. If I am reading this correctly, local variables in a language such as C++ or C# are not exactly analogous to ...
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2answers
99 views

How to localize the symbols x,y, A, B in the following program? [closed]

I see a example in Paul Wellin's Programming with Mathematica An Introduction, 4th edition: ...
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1answer
95 views

ParallelTable not firing

...
0
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1answer
284 views

Implementing Rayleigh criterion method for finding the resolution of an optical system

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
989 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 ...
0
votes
1answer
120 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
42 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
2answers
142 views

Improving code for comparing and modifying nested matrices

I have a matrix such as: ...
0
votes
1answer
192 views

Using Findroot within a loop

I am trying to get solution to an equation in a loop. The isolate equation works ...
0
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1answer
115 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
0
votes
1answer
55 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
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2answers
109 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
76 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
116 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
221 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 = ...
0
votes
1answer
176 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 ...
0
votes
1answer
226 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. ...
0
votes
1answer
74 views

How to improve this function that selects parameters from arbitrary distribution using Recursion?

Below, I have defined a function using Which to select model parameters based upon various conditions. My questions are: Is there any danger in writing this function using Recursion? Is there a more ...
0
votes
1answer
38 views

Why does this cause an error? [closed]

In[73]:= f[x_] := Save["C:\\Users\\user\\Desktop\\file", x <> x] f["###"] During evaluation of In[73]:= Save::sym: Argument ...
0
votes
1answer
66 views

converting DO loop into NestList form

I would like to rewrite this Do loop using NestList. Can you help me? ** DO loop ...
0
votes
1answer
32 views

New output cell generated for each run of a GraphicsGrid - is there a way to simply update the same output cell each run?

I have a Code cell that generates a set of plots in a GraphicsGrid[]. Each time I execute the Code cell, a new Output cell is generated. Is there a way to simply update a single output cell instead ...
0
votes
1answer
65 views

Data file organized in strings

I am working in a data set : The original question, They are strings of thousands stars,and each one contains a lot of parameters, and the following item is called identifies, they are the names ...
0
votes
2answers
154 views

Exctrating data information from a file.txt

I really did previous long search in the site and I couldn't find any answer that might help me. So I am asking it. I have the following data set, ...