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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3
votes
2answers
628 views

Dynamic lists as function arguments

Suppose I have a function that requires a list is as input. I.e. f[list_]:=DoSomethingWithList Now, if I pass a variable as Dynamic like this ...
3
votes
2answers
97 views

How do Forms affect the interpretation of Expressions?

Below are three formats for representing an undirected edge between vertices a and b: ...
3
votes
3answers
100 views

How to compare and remove x-coordinates (and the associated y-coordinates) that are less than previous x-coordinates?

I am using Mathematica version 9.0 and am trying to compare and remove x-coordinates, and the associated y-coordinate, that are less than previous x-coordinates. Below is an example using sample data. ...
3
votes
2answers
144 views

Why the function cannot achieve the expected result?

Today, I write a toy code (Framed the prime in a list) to practice Mathematica programming ,which as shown below: Trail 1: ...
3
votes
2answers
352 views

How to automatically restart Mathematica kernel after out-of-memory error

I want to run a Mathematica code repeatedly, even after the kernel shuts down when it is out of memory, because I have designed my program to continue appending the data to a file. Currently, I have ...
3
votes
2answers
2k views

How to linearize an expression automatically?

I would like to automatically linearize some long equations in the scope of variational calculus. Here follows an example of what I need to do : Given two variables $a_1 = q_1 + \delta q_1$ and $a_2 ...
3
votes
3answers
171 views

Simplifying already defined symbols

Consider the following code: ClearAll[x, y] x = y; y = 2; ?x ?y This will store $x$ being equal to the variable $y$, and $y$ having the value of $2$. Now switch ...
3
votes
1answer
696 views

How to make GraphicsGrid with content tight inside it?

I am trying to use GraphicsGrid to typeset some labels for my plots. I found the labels look little better when I use GrapicsGrid vs Grid. The labels have equations in them and not just plain labels. ...
3
votes
2answers
78 views

union several arrays of same flag(date for example) efficiently

Suppose I have several arrays from data files which look like: arrayi = {{datei1, xi11, xi21, ...}, {datei2, xi12, xi22, ...}, ..., {datein, xi1n, xi2n ,...}} ...
3
votes
1answer
383 views

How to use Mathematica for traditional programming

I am new to the structure of Mathematica. I understand that in the notebooks, one enters the symbolic expressions and evaluates them. But I need to generate some simulated data and do that a few ...
3
votes
1answer
2k views

Executing a .m file from the Linux command line

I have some code in a file named Demo-3.m, It can be evaluated in Mathematica 9. The final expression in the file is ...
3
votes
1answer
177 views

How do I use StringReplace to replace repeated characters?

Suppose I have str = "dededekmkmkmvkfjdedemkvmlvdedekfmmdedededemkmkde" And I want to replace the repeated "de"s to one and produce (in a real example, the "de"...
3
votes
3answers
784 views

Need help with exception handling

I have read the docs for Catch, Throw, and friends multiple times, and I confess that I find them utterly incomprehensible... ...
3
votes
2answers
274 views

Recursive Euclidean algorithm in Mathematica

Can anyone explain to me how do I use a recursion, if I don't know the limit? For example, I need the remainder $r$ of the Euclidean algorithm for $\gcd(a,b)$ which equals $0$. I figured out that the ...
3
votes
1answer
174 views

How do I create an array by applying a function to the index of each element?

I am looking for something like matrix(m, n, f), but for Mathematica rather than MuPAD, and for arrays rather than matrices. That is, I'm looking for a(n efficient)...
3
votes
1answer
314 views

Call Functions From File Without Modifying Context (Sandbox)

Let's say I have file named test.m containing test[arg1_] := ( Print[arg1];) What is the best technique for calling test like ...
3
votes
1answer
265 views

Using single replacement rule to convert algebraic expression

I have been trying this problems for hours and cannot find any helpful clues. How can I convert $Sinh[3\theta]+Sinh[\theta]$ to a rational function of x given $2Sinh[\theta] = x-x^{-1}$ by using only ...
3
votes
1answer
285 views

Computing closest set of points to each point in large set — running out of memory (arrays unpacking)

I have a large set of points in 3D and I'm trying to identify all the points that lie within a certain distance of each point. Then using this data store the vector between the pairs of points. I ...
3
votes
2answers
100 views

How to create some macros

I have two question in one. In the following code, I want to manipulate a plot in a centered cell. It is fastiduous to try always to remember the way to act. Could I define some macro as in a standard ...
3
votes
2answers
173 views

How can I do a Do While loop [duplicate]

Many languages have a Do While loop, how can I do one in Mathematica ?
3
votes
1answer
160 views

Programming for matrix manipulation

I want to write a programme which operates on nd x nd matrices. The programme looks the matrix as a n x n block matrix where ...
3
votes
1answer
108 views

CreateDocument options needed to suppress the default notebook menu

What are the options needed in Mathematica 10 to suppress the menu on top of any notebook created with CreateDocument? For example, the Messages window as well as the windows generated by ...
3
votes
1answer
121 views

Assign clipboard object in mathematica when print screen is pressed (windows)

Mathematica runs behind, while another window is selected. When I press print screen, I want mathematica too detect this and call a function with the picture as argument. ...
3
votes
1answer
233 views

Why am I not getting a numeric response?

Code ...
3
votes
1answer
145 views

How can I plot the normalized distribution of the Riemann zeta zeros?

Given a list of eigenvalues or a list of Riemann zeta zeros, how can I plot this famous plot found here: On the page referred to, You need to click on "Programs", "The Riemann zeta function" and "...
3
votes
1answer
108 views

Using function to transform a list

I have a list like that: {{Integer,String},....}, integer ranges from 1 to 900 and String "I" to "IV". And I need to find which pair of {x,y} each sublist is related to, so i can get a new list like ...
3
votes
2answers
153 views

RandomFunction and Histograms

RandomFunction[QueueingProcess[3, 5], {0, 15}] Histogram[data, Automatic, "PDF"] gives a very nice way to see the histogram based on the specified process. ...
3
votes
2answers
135 views

Apply Collatz Funtion to solve and print the answer

Good day to all! The objective of my task is apply the collatz function for a number x1 and print the exact number of iterations until ...
3
votes
2answers
143 views

How to define a nestable Baseform function, BaseForm output becomes BaseForm input

Mathematica won't change a number's BaseForm recursively: 63969 // BaseForm[#, 16] & // BaseForm[#, 8] & // BaseForm[#, 2] & Well, I inspected former ...
3
votes
2answers
459 views

Defining an anonymous function using another function but with fewer arguments

In MATLAB you can use an anonymous function with another function to define a new function with fewer arguments as long you define the excluded argument before, e.g. ...
3
votes
2answers
168 views

Bare symbol invocation fails but not if used with an argument

How to achieve the following behavior on a symbol f? Background: The main goal is to use the symbol to tag an abstract data structure where downvalues are used to store information. Only defined ...
3
votes
1answer
516 views

How does FindInstance work?

I was asked a question one day: find an integer n such that the first five digits of 5*7^n is 12345. It's very nice that I can quickly write code like this: ...
3
votes
1answer
149 views

Difference between Directory[] and NotebookDirectory[] .. a trailing /?

The following was the code: Directory[] NotebookDirectory[] The output was ...
3
votes
2answers
776 views
3
votes
1answer
132 views

How to make a pattern to change x^(2/y) to (x^2)^(1/y) for any x and y?

This might have been asked before. Please let me know if it is. I was looking at an interesting Mathematica question in students forum and trying to solve it, and a chance to learn more about ...
3
votes
2answers
110 views

Matrix Diagonalization programming

I have a very simple problem, with me misunderstanding the use of Modules and Functions in general, in mathematica. I have a function of which I want to input a Matrix, and in the function I want ...
3
votes
1answer
157 views

Error propagation code

I have a code for error propagation :- ...
3
votes
1answer
126 views

Efficiently generating plots from lists of differing lengths

I guess this is more of an informatic question. A quite complicated function of mine generates me a list of valid points, depending on a parameter, like this: ...
3
votes
1answer
127 views

Way to generate all multisets

I have a set $\left\{\{1,2\}, \{3,4\}, \{5,6\}, \{7,8\}\right\}$ (for example) and want to generate all sets of $n$ elements with repetition but without counting the same multiset twice. So I want my ...
3
votes
1answer
254 views

How to replace While construct to NestWhile(functional-style) correctly?

Recently,I find the program of @J.M. about Get a "step by step" evaluation in Mathematica is a very useful example for learning Mathematica programming. In the function ...
3
votes
1answer
93 views

EndOfFile error

I have a LARGE file (14.6 GB) that I want to separate into several smaller files. Because of its size, using Import/Export is not feasible, I think the most reasonable way of handling this would be ...
3
votes
2answers
244 views

My code for solving n queens problem Compile Failed

I want to make my code for solving n-queens problem faster, but it seems that MapIndexed can't be compiled. Mathematica return CompiledFunction::cfse: Compiled ...
3
votes
1answer
87 views

Fastest way to select the longest cell

I'm trying to learn low-level notebook programming and I have a question. Is there faster way to select the longest cell in a notebook than this: ...
3
votes
1answer
662 views

Nested Sums to multiple sum

I would like to automatically "move nested sums to the left". I mean, just take out of an expression all the summations and go from a nested Sum to a multiple sum. Something like starting with: ...
3
votes
1answer
187 views

Image background subtraction using parallel computing

I am developing a program for pattern recognition. I want to use the parallel computing to get a real time application. I have two cameras where each one gives n frames/second. I need to process the ...
3
votes
3answers
167 views

Composing function returning list and function taking multiple arguments

What is the easiest way to compose a function that returns a list of $n$ elements with a function that takes $n$ arguments. If I know this $n$ a priori, I can do something like ...
3
votes
1answer
181 views

Writing this loop in Mathematica

OK, so I've never had to write a line of Mathematica code (except for using it interactively as a calculator), but for this it looks like I have to. If someone could provide me with the code for the ...
3
votes
2answers
690 views

Matrices and polynomials: MMA 8 vs. 9?

I want a function to take a polynomial from a list, plug a certain matrix T into that polynomial, and return the answer as another matrix. My program uses the applyPoly function suggested by a user in ...
3
votes
1answer
420 views

How to determine cluster membership using FindClusters?

I have a 1000 by 3 data matrix in which for each person we have 3 scores. I want to cluster those persons into 8 cluster using Agglomerative method. I did the clusetring by: ...
3
votes
1answer
108 views

Generating Palindromic_number [duplicate]

I'm trying to construct Palindromic_number, I came up with this code: ...