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.

learn more… | top users | synonyms

1
vote
1answer
463 views

Equivalent of Python's “all” function in Mathematica

The Python function def isPrime(n): return all(n % i for i in xrange(2, n)) checks if a number is a prime number by using ...
22
votes
2answers
608 views

When to use Get vs Needs

When should I use << vs Needs? I just always use Needs as ...
3
votes
2answers
143 views

Localizing Pattern Names

When I want to define a function that uses a pattern, how should I localize the pattern name (i.e., x_ localizing the symbol x)? ...
4
votes
2answers
286 views

How can I use Max[] in a function that is passed a list not find the max of the list

For most functions in Mathematica, passing them a list will call the function on each element of the list. For example: ...
3
votes
1answer
321 views

Do “objects” in Mathematica have to be declared?

A while ago I learned a trick which allows one to imitate object-oriented programming in MMA using SubValues: ...
12
votes
5answers
2k views

How can I get exactly 5 logarithmic divisions of an interval?

I'd like to get exactly 5 divisions from x to y on a log scale. Can FindDivisions do this?
0
votes
1answer
1k views

Getting imaginary data from known real data using Kramers-Kronig relations [duplicate]

Possible Duplicate: Kramers-Kronig in Mathematica I am trying to get epsilon2 (imaginary part) from known epsilon1 ...
4
votes
1answer
597 views

How to combine a set of Plots, including self-drawn Inset/Lines/Circles?

I have a set of 9 plots which should be combined into one plot. Each of these plots contains a ListContourPlot, some circles, lines and an ...
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 ...
7
votes
1answer
534 views

Communication between parallel kernels

Greetings. This is my first post here, also, I am not a seasoned programmer, so any advice pertaining to coding that is not directly related to the problem (stated below) is welcome. I am having ...
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 ...
14
votes
1answer
321 views

Modules that initialize themselves on first call

I use a lot of functions that extract a specific data item from a file with many data items. I want these functions to load data (slow) and return the item (fast) on first call, but just return the ...
5
votes
2answers
175 views

How to silence all messages associated with a built-in symbol?

The post title's pretty much says it all... The reminder of this post just describes the little headway I made with this problem, FWIW. One would hope that ...
4
votes
2answers
835 views

Split string into sub-strings of length n [duplicate]

Possible Duplicate: Partition string into chunks How can I split a string into sub strings of length n? For example I have a string "ABCDEabcde1234" ...
6
votes
2answers
643 views

Web scraping and multi-threading in Mathematica

I'm working in some web scraping using Mathematica, and today, to speed-up the process, I used bash commands (xargs with parallel options with curl and wget) using ...
0
votes
2answers
132 views

How to avoid restart during development? [duplicate]

Possible Duplicate: How do I clear all user defined symbols? During package development things get messed up quite often. (especially when playing with notations) Is there a simple way to ...
8
votes
3answers
464 views

how to read in a file in the same directory?

Now I am writing a small package. I have written several files and put them in the same directory. And some files need to read in or include another file in the same directory. But when I simply write ...
27
votes
4answers
1k views

Are there suitable versioning systems for Mathematica notebooks?

I am considering a project using Mathematica and openCL. I know that the openCL C source code can be tracked. Has anyone used a versioning site or software so multiple developers can modify a common ...
4
votes
1answer
163 views

Transform sequential cell operations to programmatic workflow

Let's say I have a workflow that involves importing images and turning them into an animated gif. Here's how I currently have it setup: Import Images: ...
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 ...
9
votes
1answer
1k views

Multi-objective genetic algorithm in Mathematica?

Is there any implementation of a multi-objective genetic algorithm for Mathematica?
4
votes
1answer
285 views

How to organize and run functions?

I am very new to Mathematica. I thought I would try it out for my first assignment in my computer science class. Until now I have only used C-base languages including C#, Java, Objective-C, and ...
3
votes
1answer
494 views

FindMinimum, NMinimize, etc. with external process

I was hoping to be able to use MMA's minimization power to work with an external process. I want to minimize the function 'TryThisNumber[x_]' which sends the value of x to something external and gets ...
1
vote
2answers
243 views

How to insert an expression in a Mathematica program?

I need to insert a very large expression in a Mathematica program. So I first Put[large expression,"file"] and then use Block[{}, Get["file"];...] to ...
20
votes
3answers
454 views

How can I regroup elements in a list into a tree based on their values?

I have a list of elements in an outline, here is an example that is only 3 levels deep: ...
4
votes
3answers
201 views

Is it possible to replicate the “magic” of OptionPatterns[] with DynamicModule's local variables?

Creating richer interactive interfaces that are generated by a DynamicModule invariably requires more complex data structures and in particular, a larger argument ...
9
votes
2answers
186 views

How can I build an inline documentation utility?

I often have a large function to which I add inline comments, but then I can't see the forest for the trees. How can I make a tool that extracts the comments and tokens within them to generate an ...
19
votes
11answers
1k views

Generating an ordered list of pairs of elements from ordered lists

I have a pair of ordered lists. I want to generate a new ordered list (using the same ordering) of length n by applying a binary operator to pairs of elements, one from each list, along with the index ...
6
votes
2answers
175 views

Is Package development (via InitializationCells) compatible with creating new Notations (via MakeExpressions)?

Can new (lower-level) notations be readily used within package code? There are a few notational additions that might improve my code base but I'm not sure if these will end up being more trouble than ...
6
votes
3answers
266 views

Scope within Context

To define some package-wide functions/variables, what approach is recommended? I tried to use contexts with the Begin function, but this failed: ...
16
votes
4answers
1k views

Elegant manipulation of the variables list

I have a list of global variables (some of them are indexed variables), for example: varsH = Hold[U0[1], U0[2], B0, V0[1], V0[2]] Or (if it is easier to handle) ...
13
votes
1answer
426 views

Evaluation indicator for a notebook

I have a GUI with a number of TabView and other Manipulate controls. Sometimes clicking from one tab view to the other can take ...
14
votes
2answers
344 views

How to make use of NumericQ[x] = True (and use it safely)?

Basic Issue: I'm trying to understand the proper use of NumericQ's "magical" capabilities. Please consider the examples below. Actual question and some links are ...
4
votes
1answer
212 views

Help with Permutations

I am currently trying to generate a list of permutations of length 2 of elements of a list of strings. For example: ...
7
votes
2answers
355 views

find subsequences of constant increase

A list like l = {0, 1, 2, 3, 4, 5, 7, 9, 12, 13, 18, 19} may have subsequences of constant increase, $a_{n+1} = a_n + k$. For example: ...
8
votes
3answers
572 views

How to ensure that Polygon[list] plots a simple polygon?

Consider the following code which plots a triangle. p = {{0, 0}, {.2, 0}, {0, .2}}; {Cyan, Polygon[Dynamic[p]]} // Graphics Then adding (for example) ...
57
votes
11answers
11k views

How to check if a 2D point is in a polygon?

Background: I use code from An Efficient Test For A Point To Be In A Convex Polygon Wolfram Demonstration to check if a point ( mouse pointer ) is in a ( convex ) polygon. Clearly this code fails for ...
19
votes
5answers
1k views

How to perform a depth-first preorder traversal of an expression?

Due to confusion of terminology on my part I asked the wrong question before. Since it has already received other answers I shall not edit it, but instead ask the question I meant to in the first ...
21
votes
6answers
839 views

How to perform a breadth-first traversal of an expression?

Mathematica provides functions that perform a depth-first traversal, or which use such a traversal, including: Scan, Count, ...
3
votes
2answers
401 views

Dynamic lists as function arguments

Suppose I have a function that requires a list is as input. I.e. f[list_]:=DoSomethingWithList Now, if I pass a variable as Dynamic like this ...
6
votes
2answers
209 views

Can individual locators in LocatorPane be temporarily disabled?

This follows up on another question about the sensitivity of Locators in a a LocatorPane. I would like to be able to enable/disable individual locators in a LocatorPane. In the simplified version of ...
1
vote
1answer
264 views

Code to draw geometry doesn't run

I'm new to Mathematica and have no background whatsoever in programming, although I will teach myself soon. I was wondering if one of you programming pros could help me out. I received a code from ...
10
votes
3answers
433 views

Generating Linear Extensions of a Partial Order

Given a set $S$ and a partial order $\prec$ over $S$, I'm looking for a way to "efficiently" generate a list of linear extensions of $\prec$. Suppose the partial order is given by a ...
11
votes
4answers
630 views

Reproducing Image Patterns with Mathematica

Surfing on the net I stared at this pattern. It´s a bamboo steam, and it´s awesome. I'm new to Mathematica so I'm a little lost, I'd like to try to reproduce this pattern, of course in a very ...
3
votes
2answers
160 views

How to create an ImagePartition type-of-function that generates parts of different sizes

Background: I partition images to polygons ( squares ) and color them with VertexColors. I want to use a minimal number of polygons while still showing a clear resemblance of the original image. - ...
8
votes
2answers
333 views

Restrict Sensitivity of Locators in LocatorPane

We can restrict the movement of locators in a LocatorPane as follows: In the following example, the first locator's movement is confined to the x-axis and the ...
11
votes
2answers
3k views

Pass function or formula as function parameter

I can write either Integrate[x^2, {x,0,3}] or f[x_] = x^2 Integrate[f[x],{x,0,3}] and get the same computation. Suppose I ...
21
votes
2answers
1k views

Code Readability and Object-Oriented Code

The basic problem I have been running into is making readable code, where in other languages I am more familiar with I might have been using class or struct like objects. For example, you can imagine ...
1
vote
1answer
236 views

How can Time be made to go backwards?

I would like to make a countdown timer, but cannot find a reliable method to make the DateList[] function reverse. The not so robust code for the Digital Clock with the display of seconds follows: ...
10
votes
3answers
356 views

How can I hold UpValues but evaluate other expressions?

Consider these definitions: own = "OwnValue"; down[_] = "DownValue"; sub[_][_] = "SubValue"; N[n] = 3.14; _[___, up, ___] ^= "UpValue"; The attribute ...