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
vote
1answer
790 views

pointer like operations in mathematica and evaluation control

I would like to create a data structure of the type "header[pointer]" where pointer would point to a list. I will shown on an example how I'd like this to work, and where the problems are. ...
2
votes
0answers
125 views

Programming Mathematica - Introduction by Paul Wellin [duplicate]

Possible Duplicate: Where can I find examples of good Mathematica programming practice? Can anyone recommend a decent book on programming mathematica ? I came across this which looks to be ...
12
votes
1answer
1k views

Use Mathematica as a terminal

I love how notebooks work in Mathematica. You can edit code in real time and hit Ctrl+Shift to run it. Additionally you copy and paste different cells around to organize and test ideas. Search ...
9
votes
2answers
526 views

Is there a Break[] equivalent for short-circuiting in Table?

I am running Mathematica 7. The following is admittedly a silly example, but suppose that I have a list list whose entries are either ...
8
votes
2answers
2k views

Easier program for period of Fibonacci sequence modulo p

For a little project I need to calculate the period of a Fibonacci sequence modulo p, for which p is a prime number. For example, the Fibonacci sequence modulo 19 would be: $$0, 1, 1, 2, 3, 5, 8, 13, ...
1
vote
1answer
169 views

What is the new command for AffineMap?

AffineMap was present in Mathematica version 4. What is the equivalent command in the current version of Mathematica?
265
votes
25answers
35k views

What are the most common pitfalls awaiting new users?

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...
8
votes
1answer
90 views

Aborting from inside a Dialog

Suppose I got in a Dialog and wanted to not Return but Abort the computation. How could I do ...
5
votes
1answer
380 views

Simplification of double symbolic sums containing a DiscreteDelta without explicit summation range

I am trying to get Mathematica to automatically do simplifications like the following: $$\sum\limits_{q}^{q\in qV}\sum\limits_{q'}^{q'\in q'V}{f(q)g(q')\delta(q-q')}=\sum_{q}^{q\in qV}{f(q)g(q)}.$$ ...
16
votes
3answers
749 views

1D Random Walk variant

I am making a notebook that is a variation to the traditional 1d random walk problem. The normal 1D random walk can be simulated easily by ...
3
votes
1answer
519 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: ...
20
votes
4answers
944 views

Efficient circular buffer?

I wish to create an efficient circular buffer. That is, I wish to keep a fixed length list while appending a new value and dropping the oldest, repeatedly. As we know lists in Mathematica are ...
5
votes
3answers
277 views

How could I implement the equivalent of NextPrime

I would like to know what an implementation of the function NextPrime would look like if it were implemented in Mathematica's core language.
2
votes
1answer
161 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 ...
0
votes
1answer
332 views

Finding resolution of an optical system using Rayleigh criterion

I want to use the Rayleigh criterion to find the resolution of an optical system. I have two functions f1 = Sinc[x]^2 and ...
1
vote
2answers
328 views

How can I find minimum and maximum of a region?

I have a regionplot like the following: ...
4
votes
2answers
325 views

How can I compare the previous value and the current value implemented during NestWhileList?

I am trying to write a part of my code. I am using NestWhileList. However, I couldn't find out the right syntax for testing. It should compare previous result and current result and continue if it is ...
14
votes
4answers
3k views

How to modify function argument?

Usually in programming languages, function arguments are normal local variables, which can be modified. Is this not true in Mathematica? ...
11
votes
4answers
567 views

How to write this without For loop

Suppose I have a few lists of numbers and want to exponentiate element-wise, then sum up everything into a polynomial. For example, if I have ...
4
votes
1answer
153 views

NumberForm and units

NumberForm can be used to print Quantities to a specified precision. For example, x=Quantity[5.123456789,"Meters"]; 5.12346 m Print[NumberForm[x,{4,2}]] 5.12 m ...
12
votes
4answers
1k views

Pure Functions with Lists as arguments

Assuming I have two function: example 1: add[{x_, y_, z_}] := x + y - z add[{1, 3, 5}] If use pure function,I know I can write it as : ...
1
vote
1answer
110 views

How can I find the row differences of a matrix?

How can I compute the row differences of an m x n matrix to obtain an m-1 x n matrix; that is, given how do I obtain
0
votes
1answer
285 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 ...
2
votes
2answers
780 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
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 ...
10
votes
1answer
951 views

Coding mistake? [closed]

I have just started using Mathematica with v9.0. I am trying to follow a computation from a book on Fourier series with the function $f(x)=x$ on the interval $-\pi < x < \pi$. Here is the code ...
8
votes
4answers
528 views

Efficient code for the Ten True Sentences puzzle

I am trying to solve Ten True Sentences Puzzle. Take a look at the following sentences: The number of times the digit 0 appears in this puzzle is _. The number of times the digit 1 ...
0
votes
3answers
533 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): ...
0
votes
2answers
150 views

How to obtain a smaller-sized output from Solve

I am solving a system of 15 simultaneous linear equations using Solve. On running the code, I get a message saying "A very large output was generated" with options ...
4
votes
2answers
283 views

How can I find the lines that go through?

I have a 80 x 80 x 50 dataset. From this dataset, I get some curves. These curves are randomly seeded, by which I mean that their starting points have been chosen randomly. Below, you can find an ...
5
votes
1answer
1k views

How can I view the code implementing a built-in Mathematica function? [duplicate]

Possible Duplicate: What is the most convenient way to read definitions of in-memory symbols when we don’t have the source files? I would like to look at the code that implements ...
2
votes
3answers
280 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 ...
12
votes
4answers
509 views

Can you recommend an efficient method for finding the least integer satisfying my inequality?

I tried find the minimum make $\frac{1}{2}+\frac{1}{2+\sqrt{2}}+\frac{1}{3 +\sqrt{3}}+...+\frac{1}{n+\sqrt{n}}>15$ Following code is so slow when I use condition ...
1
vote
1answer
192 views

How do I insert a piece of code in Mathematica?

In Fortran, I can use include "file" to insert a piece of code. Is there a similar method in Mathematica?
5
votes
1answer
240 views

Should Row be used in place of StringForm?

I've been using Mathematica for a long time, so I have a habit of using some of the older functions even when newer, better ones have been added to replace them. ...
8
votes
3answers
277 views

Grid without lines, but with dots

I want to build a grid to look like the top-left table shown below, but without an outside frame. Here is what I've tried to do: ...
48
votes
2answers
2k views

Once more on object orientation in Mathematica: does it have to be so hard?

Recently I came across a set of problems which would be solved most easily within an object-oriented approach. I first attempted to solve them by other means, but found the complexity of the code ...
5
votes
4answers
2k views

How to find the sum all even numbers of this sequence?

I have a sequence $(u_{n})$ $$u_1= 1, \quad u_2 = 2, \quad u_3 = 3, \quad u_{n}= -u_{n-3} + 3u _{n-2} +2 u_{n-1}, \quad \forall n \geqslant 4.$$ I want to list the first $20$ terms of this sequence ...
14
votes
3answers
668 views

How can I improve my code for drawing a tree?

This code draws a tree, but it's not in the functional style. ...
5
votes
3answers
318 views

More structure in Source Code/Notebooks

Mathematica is great for small and quick projects and has a great syntax. However as soon as a project grows I run into trouble. How do you scale and maintain projects in Mathematica? What is beyond ...
11
votes
8answers
512 views

Any built-in function to generate successive sublists from a list?

Given lst = {a, b, c, d} I'd like to generate {{a}, {a, b}, {a, b, c}, {a, b, c, d}} but using built-in functions only, ...
4
votes
2answers
232 views

About extension fibonacci

I have been trying to solve this problem, it worked slow. I know there is a efficiently way. How do I get it? The following is my code: ...
3
votes
1answer
130 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 ...
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
vote
1answer
111 views

Draw from HistogramDistribution with ParallelTable

I wanted to check something, but ran into troubles using HistogramDistribution in combination with ParallelTable. The code does the following: Compute a HistogramDistribution of some sample and use ...
1
vote
3answers
2k views

How to create functions of arbitrary number of variables? [duplicate]

In the following code what would be the simplest way to generalize it to say some $N_f$ number of $z$ instead of just $z_1$ and $z_2$? ...
22
votes
2answers
491 views

How to implement FittedModel like objects

In the course of making some RLink wrappers I want to have some richer containers like Mathematica does with its FittedModel ...
6
votes
5answers
476 views

How to compile the code for generate Pythagorean_triple?

I am finding Pythagorean_triple, it worked slowly. I tried to compile, but it gives some warnings. I also use "Case" or "Do" ,both of them failed.I'm sure my CCompiler has been set correctly. How can ...
7
votes
3answers
1k views

Filtering elements from a list

Suppose that I have a list {{{2, 1}, {4, 3}, {2, 4}}, {{2, 1}, {4, 3}, {3, 1}}, {{2, 1}, {2, 4}, {3, 1}}, {{4, 3}, {2, 4}, {1, 2}}} I want to make a new list ...
7
votes
3answers
538 views

NDSolve and {C, K, Slot} and other built-ins as a variable name

The following problem is an exploration of what causes the error "Input is not an ordinary differential equation" in Mathematica as it seems to have changed from version 8 to version 9. Specifically ...