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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1
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2answers
70 views

Ask about the variable and constants in partial derivative in a loop

EDITED I have a function in a list like : func={2(x^2)+x*y+3(y^2)}; I want to have a UI that ask me which parameter (x or y) is a variable in a ...
2
votes
2answers
60 views

Sum broken into two sub-sums according to a condition on the terms

I have a sum in mind, but I want to break it into two sums and get a separate total for each of the two. All cases where the square root is accurate, i.e., exact All cases where the square root is ...
4
votes
3answers
121 views

How to get multiplication of the elements of a specific list/Matrix

Assume there is a list: List1={a,b,c,d}; Then I want to get these calculation: ...
4
votes
1answer
104 views

How to check the option value?

Given that I have a function func as follow: To check the value of options, I using the step-by-step method If[] ...
4
votes
1answer
64 views

How to define an expression which is differently evaluated in calculations and printed

Let's say, we have a list: values = {1.2, 0.04, 0.9}; Is it possible to replace 0.04 by some expression, which displays as ...
0
votes
0answers
55 views

How to spend any image in “2D” or “3D” to an image mesh, ie as a wire frame in black and white?

How to spend any image in "2D" or "3D" to an image mesh, ie as a wire frame in black and white? For example some of these: edit :example output
9
votes
1answer
98 views

How to implement a custom random process object?

I want to implement a custom random process thing1 to pass to RandomFunction. The process I have in mind is conceptually extremely simple: two alternating Poisson ...
1
vote
0answers
57 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 ...
0
votes
0answers
73 views

Fun/Frustration With Coding Coding Theory

I have code following from this post: http://math.stackexchange.com/questions/1317722/fun-frustration-with-coding-coding-theory I think I am done with the code, but now I face a single problem. The ...
2
votes
1answer
145 views

How to determine whether an expression can act as a “good” function?

It's not easy to see whether an expression can act as a "good" function. A good function refers to an operater that transforms symbolic entities like 1+x^2 or ...
1
vote
0answers
61 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 ...
5
votes
0answers
43 views

How is CellContext->CellGroup supposed to work?

After reading the documentation on the subject, I still cannot get CellContext->CellGroup to work. Here's a simple example. (Unfortunately, I cannot easily ...
4
votes
1answer
139 views

Can I do constraint programming in Mathematica? [closed]

I would like to know if there is a way to do constraint programming in Mathematica? I think there are no built-in functions, but maybe some of you know some additional packages addressed to the ...
0
votes
1answer
79 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: ...
9
votes
0answers
87 views

Confused by the opts : OptionsPattern[ ] pattern

I'm trying to make sense of the syntax in the clause opts:OptionsPattern[], as found in this standard "rule-based" (pseudo-)function definition pattern: ...
1
vote
1answer
43 views

Why this isn't a valid argument? [duplicate]

I am having truble understanding why F1 produces an error, since both time and velocity are the same kind of object: ...
0
votes
1answer
55 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 ...
3
votes
1answer
84 views

Is it possible to update Dynamic objects even when they are off screen?

I am using Dynamic and DynamicModule to display graphics/statistics generated from a long-running set of parallel tasks. The ...
13
votes
2answers
343 views

How to programmatically ask if Mathematica is running as an Administrator

To avoid execution problems in a program I need to know if Mathematica has been "Run as administrator". What would be the cleanest way to programmatically getting this information?
0
votes
0answers
13 views

Number of pairs (a, b) such that a*b < N where a, b, N are integers greater than 0 [migrated]

I have this code in C to calculate number of such pairs:: ...
5
votes
0answers
186 views

How to create protected single-file stand-alone CDF applications

After hours of work trying to understand how much protection I can get when creating stand-alone CDF applications I have come to the decision that the best protection to my work is provided by ...
0
votes
1answer
55 views

How to count column occurrences in a matrix?

I have a matrix of data, and I want to count the number of columns that match, and have some way to organize them by frequency. But I don't want to count the entire column, but consider the matrix ...
5
votes
1answer
115 views

Reap, Sow with Parallelize: bad performance, why?

I have a question about the performance of Reap and Sow with Parallelize. I am aware of the following questions How to collect result continuously (interruptible calculation) when running parallel ...
1
vote
1answer
50 views

Emulating Case Pattern replacement

As most regular users, I have developed utility functions complementing the Wolfram language for frequent tasks. In particular, I have variations on Cases (see ...
1
vote
1answer
140 views

Transform linear system into a matrix form

I have a system of linear equations in variables $A_n$ of form: $$ \sum _{k=-K}^K h_k A_{n-k} J_{n-k}\left(\frac{(1-i) \text{$\eta $Sqrt}(n-k)}{\sqrt{2}}\right)+A_n\left(\frac{(1-i) \eta ...
2
votes
3answers
101 views

Problem with the output of a function I program

(This is the function that I programmed) Zm2[Z_, nk_] := (zm2 = 0; For[i = 0, i < Length[Z], i++, zm2 += nk[[i]] *Z[[i]]* Z[[i]];]; Return[zm2];); ...
3
votes
1answer
160 views

How to further accelerate arithmetic with Fermat Pseudoprime and Fibonacci number

I've been working on this all night, and I have made this go pretty fast, compared to my first iteration of the program, but now I'm out of ideas. I'm trying to write a program to test (by good ...
2
votes
2answers
145 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 ...
10
votes
2answers
214 views

Built-in symbols that support operator form

In version 10 some built-in symbols are updated to support operator form like the Derivative. For example, Select, ...
0
votes
0answers
47 views

Calling a custom function in slave kernel process connected through mathlink

I am performing a small experiment to check if we can call/execute a custom package function in slave kernel launched from master using mathLink. I have created a dummy application called ...
5
votes
1answer
281 views

Only `Break` from innermost loop

How could I Break from only the innermost loop in a Do[stuff,{i1,i1min,i1max},{i2,i2min,i2max},...] ? I get the desired ...
0
votes
1answer
76 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 ...
2
votes
2answers
94 views

Creating a Cayley's table of square

I'm interested in creating a Cayley's table of square using Mathematica. I'm not a programmer but occasionally resort to using Mathematica to simplify my work insofar as the programming doesn't take ...
1
vote
0answers
75 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) ...
1
vote
1answer
47 views

Is it possible to use FormObjects and FormFunction in a stand-alone notebook?

I have been looking at the FormObject and FormFunction. Can FormObject and ...
0
votes
0answers
38 views

Evaluate notebook using text-based interface

I am trying to evaluate a notebook using a text based interface so that it can be submitted to a computing cluster. I have seen this stackexchange page and attempted to use ...
1
vote
1answer
51 views
1
vote
2answers
92 views

How to find total distance covered when I have a list of GeoPositions?

So I have a list of GeoPositions and I need to find the distance covered in that order? I know I can find the distance from each city and then add them all up but I was wondering if there is any ...
2
votes
1answer
70 views

Can I use Switch with an inequality? [closed]

I'd like to have something like: Switch[x, 10, a = 3; b = 7, >10, a = 5; c = 6, _, a = 7; d = 12, b = 1]; I can't seem to get this to work.
0
votes
0answers
33 views

Debug package with command line arguments

I'm creating a package that takes as arguments input from the command line using $ScriptCommandLine. What's unclear to me is how to best debug this package. How do others perform these tasks? I ...
0
votes
1answer
65 views

How to properly use conditionals inside NDSolve

Currently I am working with Mathematica to learn the program, and I'm confused what exactly is wrong with this code. ...
6
votes
1answer
69 views

Completion in terminal?

I know that it is possible to run Mathematica in Terminal. But I didn't find a way to get completion work in Terminal. I mean completion by ...
1
vote
1answer
114 views

Fibonacci Line Search Method

I am attempting to write a code to find to bracket the minimum of a function using the Fibonacci Line Search Method, I believe my code is well written but I am not ...
0
votes
1answer
83 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 ...
1
vote
1answer
104 views

Multiply out product of sums

For a specific quantum mechanical problem I need to multiply out operators in order to calculate a trace by hand. For example I need a Hamiltonian squared with $H^2$. The Hamiltonian contains of a few ...
3
votes
2answers
323 views

How to force Return[] to return from an arbitrary point (like in C++)?

I need to test some complicated conditions to calculate a Return value. But MMa doesn't let you Return[] from anywhere the way C++ does. The structure of my Module is similar to this: ...
-1
votes
1answer
116 views

Implementing the Golden Section Rule

I am attempting to write a code which brackets the minimum of a unimodal function, using the Golden Section Method Below. I am have serious issues debugging my program though, any help will be ...
-1
votes
1answer
86 views

Trying to write my own Greedy/ Nearest Neighbor Algorithm

So I'm trying to write my own function and compare it to the results I have from using FindShortestTour. Does anyone know how to find the distance from each city to each of the others without ...
2
votes
1answer
69 views

Block works when directly used but not when used in a function

I want to calculate a derivative such as: $\delta f=\sum_{i=A,B} \sum_{k=1,2,3} \frac{\partial f}{\partial a_k^i}$. Since $ a_k^i$ are assigned values other places in the code, I have used ...
3
votes
1answer
162 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 ...