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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35 views

What does a period do when used in a test argument for Which? [on hold]

I was looking at an example for error reporting. I noticed that a . appears in the tests of a Which clause. The first test in the Which clause below is: ...
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0answers
27 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 ...
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0answers
31 views

$MessageList inside and outside Block[]

Why does 1/0 $MessageList return ComplexInfinity whereas ...
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0answers
32 views

Retrieve rendered graphics via WSTP

I am planning on using Mathematica as calculation- and rendering backend for an application, i.e.: Call Mathematica via WSTP and by using EvaluatePacket have it ...
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0answers
42 views

Trying to write a program to find an approximate harmonic function on a given graph using relation method

So given an undirected graph with two vertices that have fixed values assigned to them, a harmonic function is a function that assigns values to all other vertices such that the value assigned to each ...
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0answers
25 views

Iterating a model with 2nd order difference equations using Manipulate [duplicate]

I have a model including first and second order difference equations. It works for the case of first difference equation, which is below: ...
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0answers
70 views

Stringing functions together

My professor introduced Mathematica to my class for the first time this week and gave us the following assignment. Also a disclosure that this is the first computer science class I have taken and the ...
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0answers
55 views

Modifying Game of Life code so that the lattice can be seeded with life forms

I want to modify Game of Life code so that the lattice can be seeded with one or two new life forms like: ...
0
votes
1answer
108 views

NDSolve with initial condition: initial conditions did not evaluate to an array of numbers of depth 1(for 1D) or 2 (for 2D) on spatial grid

I have the following naive code to solve a PDE in two spatial dimensions (x,y) with periodic boundary conditions: ...
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0answers
53 views

Define column types in a Dataset - Failure on append and Typesystem

I have a basic function that populates a Dataset according to user specified parameters. ...
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0answers
12 views

all does not work [duplicate]

Thanks blochwave for giving me a detailed answer, but I have already used all these methods and none of them has worked well, it is clearly written in mathematica "get help" file that the Timing[] and ...
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0answers
38 views

How to simultaneously change variables shared by several functions?

I designed a fit program, the framework follows: a matrix build function: Q[a_,b_,c_,d_]; several matrix manipulate functions shared the variables {a,b,c,d} like this: ...
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1answer
74 views

How can I use manipulate on multiple lists within a function?

So I have my N-Body Problem set up like so, and I can plot it in ListPointPlot3D, but I cannot figure out how to stick this into a manipulate function. ...
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0answers
81 views

I cannot pass any script to `math`, in a command line

I want to run some lines of Mathematica code by a command-line call for math. As a test, I save just the following code in a file ...
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0answers
50 views

Question about treillis structures

I have difficulties finding a command to plot multiple segments connected in nodes in Mathematica. Ultimately, my goal is to modelise something like this by entering nodes coordinates. Also, the ...
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0answers
122 views

Solving for a Transfer Matrix

I am currently working on a program that will solve a transfer matrix and extract several elements. Particularly, the transfer matrix is characterized by four elements in a ...
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0answers
45 views

Find the maximum/ minimum of the function f(x,y,z) = x+2y+3z on the curve of intersection of the plane x-y+z = 1 and the cylinder x^2+y^2 = 1 [duplicate]

How to write the program for: Find the maximum/ minimum of the function f(x,y,z) = x+2y+3z on the curve of intersection of the plane ...
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0answers
71 views

Using Animate/ListPointPlot3D on more than one list

I have a couple orbits defined which have been mapped into one array as shown: ...
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0answers
22 views

A question about conditional replacement [duplicate]

{g[x, y, z], h[x, y], f[]} /. (f_[t___] /; f != List) :> Plus[t] Why is the output of this expression ...
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0answers
33 views

what's the difference between CreateKernelLink() and CreateKernelLink(String Arg)?

I have a .NET program which will connect to MathKernel. When the program runs, there will be a icon of MathKernel on the taskbar. ...
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0answers
65 views

What is the meaning of //N in mathematica? [duplicate]

As the title says, What is the meaning of //N? i can't remember it.I tried looking in documentaion center, but it came up with nothing. Help appreciated.
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0answers
90 views

How do I perform the following numerical integration

I have the following integral to evaluate numerically: $$x(t) = \frac{1}{f(t)}\int_0^{t_b} t^m (t + n)^o \sin(pt) \mathrm{d}t \quad m,n,o,p \in \mathbb{R}$$ ...
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0answers
350 views

Converting a matlab program into Mathematica 10

I sought help from this entry at Calling MATLAB from Mathematica to see if I could CONVERT a mathlab program which simulates polymer dynamics that is provided at the download section at ...
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0answers
47 views

Path must include /TypeSystemLoader.m?

I have encountered a number of odd issues using the Wolfram Workbench 3.0 Debugger. Whenever I try to step into a Switch[] statement, I get the following error message: "Problem Occurred - Debug ...
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0answers
57 views

deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
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0answers
79 views

Timing Differences

In More efficient implementation for comparing coefficient lists in a Do-loop link, george2079 posts in his first answer a piece of code that takes 352 seconds to compute. When I run this same piece ...
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0answers
46 views

Automatic Cuda/CPU code; Fast programme run [duplicate]

I have developed my thesis codes by means of Mathematica software in a .nb file format. Despite using the available Parallel code capabilities and doing all the numerical integrations by means of ...
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0answers
38 views

Can the value of a variable be made to persist between front end sessions? [duplicate]

For example, say I create a notebook with a cell a = 5 + 2 and then I close Mathematica, reopen the notebook, enter a new cell ...
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0answers
60 views

What is a good alternative to this numerical example taken from FindFit?

I am using MMA V9.0 What do you suggest for this numerical example? I am not getting good results trying to use my own procedure to find a "best" fit using the 1-norm. The 1-norm example for ...
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0answers
93 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
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0answers
114 views

Mean Squared Deviation for Population Data

I've been using the Lotka-Volterra equation to estimate population sizes and need to find the MAD (mean absolute deviation), MSD (mean squared deviation) and mape (mean absolute percentage error) for ...
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0answers
250 views

A problem with functions and Infinite expression 1/0 encountering

Following code (function) makes integrals and then replace f[x] with Cos functions and calculate the definite parametric ...
0
votes
1answer
986 views

How can I draw this particular phase diagram in Mathematica? [duplicate]

Sketch the phase diagram for systems with the following velocity functions where a and b are constants with ...
0
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0answers
192 views

How minimize a function involving abs $(|\ldots|)$?

I am trying to decide the best way to solve this: Minimise $Y = | K + ax^2 + bxy + cy^2 |$, with decision variables $x$ and $y$ and $a > 0$. I also have a number of convex and affine ...
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0answers
117 views

Programming a Meijer G related result

I am not that new in Mathematica, but I do not remember I have ever used it for programming (like we may do in Java). I have an important result given here by this integral: $$ \int_0^{+\infty} ...
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0answers
204 views
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0answers
97 views

Inconsistent results in fits from NArgMin

EDIT: Just realized I had misspelled "inconsistent." I'm using version 7.0. I'm trying to fit a (noisy) data set to a large-order polynomial. (Just for context: there isn't a model for the ...
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0answers
40 views

Generating partitions of a set with a specified size of the parts [duplicate]

I tried the following (inspired by the answer here) myList = {a, b, c}; Needs["Combinatorica`"]; SetPartitions[myList] and I got this answer, ...
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0answers
22 views

Conflict among Permutations and Graph utilities once Combinatorica is loaded [duplicate]

I have tried to figure out and solve the problem of compatibility of Permutations and Graph utilities of Mathematica once the Combinatorica Package is loaded, but I failed :(. Could anyone explain me ...
0
votes
1answer
2k views

Loops and subroutines [duplicate]

Possible Duplicate: Alternatives to procedural loops and iterating over lists in Mathematica I am new to Mathematica and not familiar with functional programming. In particular, I have no ...
-1
votes
1answer
75 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 ...
-1
votes
1answer
69 views

How to loop in reverse order?(e.g. for i from 10 to 1) [closed]

I have a list F = {382.856, 638.53, 915.482, 1192.44, 1469.39, 1746.34, 2023.29, 2181.91} And I want to use it to calculate V: I think it should be something ...
-1
votes
1answer
38 views

Finding the number that gives remainder equal to 0 [closed]

Hi i'm not english so I'll try to explain this as good as I can . If we have for example 250 : 5 = 50 , remainder 0 let's say I don't know the number i'm going to divide (because it is generated ...
-1
votes
1answer
112 views

Transformation of a simple logic statement

I'm designing a logic circuit and I was wondering if the following two things are equivalent: (x <= y) and (x < (y + 1)) I can't think of any set of numbers that would make these two things ...
-1
votes
1answer
97 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
0answers
25 views

How could I speed up a code including a Module with many functions

I have implemented a big formula through the mathematica function Module. Within this module a lot of definitions are made (i.e. function[x_]:=). The code are working well but it is too slow. I am ...
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votes
4answers
302 views

Compare elements in a list

Assume that there are three different points in x-y coordinate like: p1={4, -1}; p2={5, -2}; p3={1, 5}; In order to compare these points to each other in a ...
-3
votes
1answer
84 views

How to make X and Y = Z? [closed]

Hello I have a big question, maybe it's extremely easy but for now I'm unable to make it work. I'm a programmer and what I need to do is for example: if X = 2 and Y = 1 then Z = 1 if X = 3 and Y = 1 ...
-4
votes
1answer
119 views

Programming Multipolar Expansions in Spherical Tensors

We have that a density matrix can be written in a basis of spherical tensors: $\rho =\sum _{K=0}^S\sum_{q=-K}^K \rho _{\text{Kq}}^{(S)} T_{\text{Kq}}^{(S)}$ for example for a 3x3 matrix, $S=1$, ...