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
1answer
111 views

ControlType -> None Vs. Module inside Manipulate (i.e. making everything local)

I'm building a program on another one made available in the Wolfram Demonstration Project. I've noticed that in the original code (working flawlessly) many variables were made local inside the ...
3
votes
1answer
75 views

Combination of CellPrint and PrintTemporary, or DisplayForm for Cells

I'm programmatically generating some formatted output that generates a cell in the form of a Cell[] expression. For instance, the output might be ...
3
votes
1answer
444 views

Control over depth-first scan and breadth-first scan

Is there a way to conditionally take control/modify the flow during a depth-first scan or the breadth-first scan ? Say, for example, if a particular node if found, consider it as a leaf-node and ...
3
votes
0answers
158 views

Distance Time Warp (DTW) function implementation in mathematica

The DTW (Distance time warp) is given here http://en.wikipedia.org/wiki/Dynamic_time_warping There is an implementation of DTW in R as well as MATLAB. However i am unable to find something for DTW in ...
3
votes
0answers
346 views

A* algorithm for finding shortest path in a graph

FindShortestPath finds the shortest path between two vertices in an edge-weighted graph, allowing a choice between the Dijkstra and Bellman-Ford algorithms. In my (limited) understanding, both of ...
3
votes
0answers
183 views

Using NVIDIA 3D Shutter Glasses with Mathematica

Mathematica has great capabilities to display 3D Graphics rendered to the 2D screen. This should make it perfectly suited to use the Graphics3D system together with an NVIDIA Graphics card, a 3D ...
3
votes
0answers
43 views

Is it possible to enclose code into collapsible/expandable regions? [duplicate]

In some programming languages (e.g. C#, Visual Basic) there are language constructs that have no effect on the execution of code whatsoever, but exist solely to allow grouping fragments of code into ...
3
votes
0answers
286 views

How to compute the Lovász number for the given graph in Mathematica?

Here is a graph whose adjacency matrix is ...
3
votes
0answers
56 views

How can I append Mathematica variables to an output file preserving both names and values? [duplicate]

I have a Mathematica program that calculates a series of large vectors that I need to save for future reference (in addition to some scalar values). I want to save all these to a file, tagged by their ...
3
votes
0answers
244 views

Malliavin Derivative with Mathematica is it possible?

Is it possible to define a Malliavin calculus with Mathematica 9? Consider a random variables on the Wiener-space $\Omega=\mathcal{C}([0,1])$ of the form ...
3
votes
0answers
162 views

I am missing a function like HoldPattern

Temporary message: I am planning to edit this question, making the examples less confusing and by moving the things that are confusing to a separate question For any confusion about expressions that ...
2
votes
5answers
452 views

How to leave function unevaluated programmatically?

Is it possible to write a function in such manner, that it can be either evaluated or left unevaluated? This is a general question. Sample below is just a sample. No need to find solution for this ...
2
votes
2answers
1k views

optimization problem with NDSolve

I want to minimize the function fcc. When fcc is calculated for a specified point the answer is correct: ...
2
votes
4answers
503 views

Using the result of Solve in subsequent calculations

I'd like to know how to use the results of Solve in later calculations. Here's what I'm doing now: This is my expression ...
2
votes
1answer
130 views

Odd edge-case behavior of Block

In this example, Block is used to localize the variable cache as used in the function g when called from the function ...
2
votes
1answer
828 views

Using triangulation

I have been presented with 3 known points and the power densities at those points. I need to use those points to find the location of the actual antenna which is generating the signals. Power ...
2
votes
2answers
1k views

Forecast Future Stock Prices - Brownian Motion - Again

excuse me, I think I have here a technical problem with Mathematica yesterday I posted the question with the title: Forecast Future Stock Prices - Brownian Motion I am still not very experienced but ...
2
votes
3answers
175 views

Using Nest inside NestList

I need results like this: {Cos[Cos[x]], Sin[Cos[Cos[x]]],Cos[Cos[Sin[Cos[Cos[x]]]]], Sin[Cos[Cos[Sin[Cos[Cos[x]]]]]], ... } I've tried to use ...
2
votes
3answers
192 views

How can I find the points of B Spline functions for a specific range?

Based on this question: I have a list of bspline functions (nearly 1000) provided by applying BSplineFunction to a list of points. I want to get the points each of ...
2
votes
5answers
128 views

GatherBy based on condition imposed on index variable

Excuse me. This might be user specific question but I need your help. I have an indexed data, where positive integers are used for indexing data. I am trying to group data putting condition on index ...
2
votes
3answers
186 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: ...
2
votes
2answers
197 views

How to replace data in a list (tree) in a functional Mathematica way?

I have list containing 2D points in various groupings, i.e. points, lists of points (figures), lists of lists of points (patterns) and finally a list of patterns. The list also contains other data, ...
2
votes
2answers
408 views

Mapping multiple functions

This question was part of a course on Mathematica written in 1998. Each of the functions f1, f2, and f3 defined below has a root near x=2. Map an anonymous function involving FindRoot[] onto ...
2
votes
3answers
279 views

How do I construct a pure function to extract data fields from records that are strings?

How can I get from data segment format to the final segment format with a pure function? The data fields are fixed length. There are no separators between the fields. a) list ...
2
votes
3answers
139 views

How to extract both first and last rows of each group from unbalanced panel data

This is a follow up question form my last question click here. I have unbalanced panel data such as : ...
2
votes
4answers
128 views

multiple sequential definitions, defining own set function

I want to define a function for doing multiple definitions, where I apply the same function f to all values, and definitions are done not at the same time but after ...
2
votes
1answer
1k 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 ...
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];); ...
2
votes
2answers
93 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 ...
2
votes
2answers
170 views

How to unprotect GeneratingFunction

I'm trying to add custom downvalues for GeneratingFunction, and to do so I thought I just had to Unprotect it. However, that ...
2
votes
2answers
2k views

Product of Fibonacci numbers using For/Do/While loops

I want to find the product of the first 20 Fibonacci numbers (the fibonorial). I want implementations using While, Do, and ...
2
votes
2answers
750 views

defining recursively a function with multiple if conditions

I am trying to recursively define a function which satisfies the following system of equations and which depends on two parameters $n$ and $l$, $$ \begin{align} A(x, n, l) &= F[ A(x,n-1,l) ]\\ ...
2
votes
1answer
816 views

Optimizing a function involving NDSolve results in error messages

I want to minimize a function f with NMinimize but an error occurs that says: ...
2
votes
2answers
144 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 ...
2
votes
1answer
187 views
2
votes
1answer
101 views

Map and Scan ignore HoldFirst

I am trying to write a simple function that takes a list of data and outputs it to a file. I'd like the name of the file to be the same as the variable that holds the list. It seems that giving a ...
2
votes
1answer
69 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.
2
votes
2answers
128 views

How to plot points with error circles on map with latitude/longitude grid

I am currently working on a project to model the location of icebergs in the northwest atlantic. When an iceberg is sighted, an error circle is plotted around it (with a bivariate normal probability ...
2
votes
1answer
181 views

What is the correct way to break a long expression across multiple lines?

This is probably a very simple question and I am probably not using the right keywords in my search; but I have a long expression that I would like to break across multiple lines to improve ...
2
votes
1answer
102 views

Please explain this while-loop

Code: ...
2
votes
1answer
364 views

Converting a nested for loop from MATLAB

In MATLAB I have the following series of nested for loops that update a matrix. (It's not my code, but someone else's that I'm trying to replicate - I don't know ...
2
votes
1answer
284 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 ...
2
votes
1answer
227 views

Is it possible to treat starting values as variables?

I have a problem where I am using FindRoot a gazillion times over a grid of parameters. I need to allow the starting values to vary a bit with the parameters to get it to converge. Here is a simple ...
2
votes
1answer
159 views

Rookie mistake in defining a function with Modules?

I can't figure out what's wrong with this piece of code. I'm trying to define a function that counts the occurrences of x, y and ...
2
votes
1answer
126 views

Import a file only if it contains a certain pattern

Let's say I have three files containing: File 1: x y z 1 4 6 File 2: x y z 2 5 9 File 3: x y z 5 4 8 My goal is to import the data from a file only if in ...
2
votes
1answer
218 views

Fighting Less::nord at the root: Any unintended consequences?

After being plagued too much by Less::nord and companions, I've decided to try to fight it at the root: The comparison operators. I noticed that typically, the bad ...
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 ...
2
votes
1answer
141 views

How to speed up my code about Divisors?

This code is about PE496 In[21]:= ParallelSum[n*Count[Divisors[n^2], a_ /; n < a < 2 n], {n, 1, 10^5}] // AbsoluteTiming Out[21]= {5.987342,10724527832} I ...
2
votes
1answer
74 views

How to package a function for export?

I often post code for functions on Stack-Exchange, and then later find that they are unexecutable - that people can't use them because I mistakenly omitted some private functions or values that are ...
2
votes
1answer
88 views

Probability evaluation fails with equals condition

The following evaluation fails (the result is just the copy of the input) $$\text{Probability}[0<x\leq a | x-y=t,\{x\ {ExponentialDistribution}[\lambda ],y\ {ExponentialDistribution}[\lambda ...