This tag is intended for the review and improvement of style for already functioning code. It not meant to change the objective of the code.

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24
votes
2answers
532 views

Copying one symbol into another

I would like to know how can I completely copy one Symbol to another. When I say copy, a refer to UpValues, DownValues, ...
14
votes
1answer
1k views

Poisson solver using Mathematica

I am looking for some help with a Poisson solver I am writing in Mathematica. The code is quite long with Arrays plugged in, so the full details can be found at http://pastebin.com/uSrSDcW6 I am ...
3
votes
3answers
1k views

Using DSolve to solve for x[t,parameter]

I'm trying to solve an ODE with two independent variables (a cannon firing from a cliff incorporating wind resistance dependent on velocity). I've tried the following for the x-component: ...
14
votes
9answers
640 views

Thread over list in different levels

I have these two lists, both with the same length in the first dimension: ...
14
votes
4answers
618 views

Button evaluation inside DynamicModule

Someone know why this Button works when clicked: ...
12
votes
3answers
740 views

Simpler way to fill date gaps with zero values

One basic problem when working with data like sales and dates is the case where you dont't have sales in all days, so you have to fill it to take information as average or to make a plot. See this toy ...
31
votes
9answers
5k views

Programming paradigm change

I'm new to Mathematica, I've been learning by myself, and, being a Java developer for some time, it makes it hard to adapt. I've tried to solve a Reddit challenge, and I came up with this solution: ...
30
votes
1answer
1k views

May the Fourth be with you

Happy Star Wars day. I was playing around with the image manipulation functions in Mathematica in an attempt to recreate the Star Wars crawl. There's an HTML/CSS implementation which is in my ...
26
votes
7answers
1k views

Splitting words into specific fragments

I am looking into splitting words into a succession of chemical elements symbols, where possible. For example: Titanic = Ti Ta Ni C (titanium, tantalum, nickel, carbon) A word may or may not be ...
7
votes
2answers
1k views

Elegant way to handle columns operations

Inspired by this question from @sjdh and by my recurrent use of columns operations in database sets, I was looking for one way to make columns operations more symetric, so I can handle with matrix and ...
4
votes
3answers
235 views

Is there something wrong with this piece of code involving Manipulate?

I am playing around with the Manipulate sentence. I think the following code is right, and actually Mathematica 9.0 doesn't return any error message, but I am ...
23
votes
1answer
716 views

Strategies for solving problems involving searches

As an example of a search-oriented problem, consider finding all constrained $n$-colorings of a graph. An "$n$-coloring" associates one of $n \ge 1$ colors to each vertex in such a way that no edge ...
2
votes
2answers
451 views

Collatz Tool Box — any speed ups possible?

I have created a tool box for experimenting with the Collatz conjecture. Info here: Wolfram MathWorld and here: Wikipedia The patterns I have found allow us to make the conjecture jump through some ...
6
votes
0answers
113 views

Fine tuning compiled code that computes dilogarithm function

As an exercise of writing a good Compile function, I want to do the simple task of coding a routine that outputs the real part of the dilogarithm function ...
3
votes
1answer
134 views

How to remove recursion, and write it functional and efficient way?

I wish to implement the following recursion efficiently. ...
1
vote
1answer
117 views

Passing function as argument

I've been mucking around with passing functions as arguments to other functions and via trial and error seem to have something that works. I was wondering if someone could have a quick look at some ...
13
votes
7answers
785 views

How to sort digits in a string while keeping other characters untouched?

Now there is a string with digits and letters, for instance, "95uge678r3gi89hgfe30kgh063d51". And the expected output is ...
13
votes
2answers
326 views

Clever use of DownValues, or failure to understand the “Mathematica Way.”

I needed to look at the changes in the values of about 4000 items from one year to the next. I have a table with identifiers and values for each year. Not all of the items are in each list. The ...
11
votes
2answers
627 views

What's the most “functional” way to do Cholesky decomposition?

I can do Cholesky in a procedural style, such as: ...
12
votes
2answers
622 views

Parsing a CSV file using Interpreter

The new Interpreter functionality in version 10 looks like it has the potential to make parsing custom data formats very easy. I'm trying to create a CSV parser. ...
4
votes
3answers
1k views

How to fix BodePlot that comes with Mathematica?

I am using Mathematica to go through the examples and exercises on the book Modern Control Systems, 6th edition by Dorf. On page 605, there is a table (Table 8.5) with the Bode plot for several ...
10
votes
1answer
374 views

How to visualize pattern matching process?

I want a function that does the same job like ReplaceRepeated, and can make the matching process visible. I searched the Internet but didn't find any existing code ...
4
votes
1answer
179 views

Feedback on my Subscript code

I have written a code, and I need a little feed back.. I want to make the Subscript distributive across (1) addition and (2) multiplication to mimic short-hand for ...
3
votes
2answers
77 views

How to define UpValues about the derivative of NBSpline when the length of knots is unknown?

Description In the book “Programming in Mathematica” 3rd by Roman.E.Maeder, the author gives a topic about A new Mathematical Function in section 8.4. For instance, for the following formula: ...
3
votes
0answers
196 views

Nonlinear FEM and FindRoot

I'm trying to develop a kind of nonlinear FEM application using mathematica to solve a bvp like the following: $$ \gamma(u') ~u^{iv} + 2 \gamma'(u') u''' u''+ u''^3 = f(x) $$ where $u = ...
3
votes
1answer
354 views

How to improve this dynamic progress bar code

I created this progress bar to use in my codes: ...
2
votes
1answer
136 views

Performance on Binomial Deviate is slow

I hope I won't get spanked for reposting. This is related to a previous question discussed here: Performance on Multinomial Deviate is slow. but this version is simpler because it is a binomial ...
1
vote
3answers
215 views

professionalize/optimize my code that calls a function

I have the following construction, which defines a function that I subsequently call in a loop multiple times. I use this very often, but I have never looked into if there is a more professional way ...
0
votes
1answer
197 views

My Baum-Welch algorithm is very slow. Is it due to Mathematica?

I've also posted this question here, since I'm not sure which community is more adequate for this type of question. I've programmed imperatively the Baum-Welch algorithm for a 2 state hidden Markov ...
6
votes
2answers
171 views

Looking for feedback on this function

I'm not sure this is an appropriate question; if not, I'm sure someone will close it :) I've got the following function, listed below; its job is to accept a graph (function) presented either as a ...
5
votes
1answer
247 views

Selecting a list from a list of lists

In working through Programming Paradigms Via Mathematica (A First Course) I have come across this two part question: A permutation of length "n" is a list of the first n positive integers in ...
2
votes
4answers
207 views

How to make multiple if statements?

I know Mathematica's if format is If[test, then result, else alternative] For example, this ...
2
votes
1answer
110 views

Writing a function to mimic Characters

I am working my way through Programming Paradigms via Mathematica (A First Course) and have answered the following question in lesson 25: Write a function of one argument "s", a String, which ...
1
vote
0answers
104 views

Collision detection algorithm (discrete) with sweep and prune algorithm for periodic boundary conditions

EDIT: Question Updated with solution approach, but solution much slower than original implementation. Any ideas to speed up implementation? In the discussion on collision detection (see here) I asked ...
1
vote
1answer
273 views

Lookup construction using data matrix and Reap/Sow versus AppendTo`s

I am a user of MMA9 and made my own kind of Lookup, which is now a standard command in Version 10. In my program there is a section in which by means of a StringReplace[ ]-command containing a lot of ...
0
votes
0answers
67 views

Matrix iteration failing after second step

I am calculating 11x6 matrix using different logics as in below code. Problem is in Do loop in below code where I have two different criteria to update matrix "fd". I am expecting logic in IF which ...
0
votes
1answer
68 views

Tutorial for Map, Apply, etc

I have this code: ...