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

9
votes
2answers
1k views

Implementation of smoothing splines function

I have some problems by writing a module for spline smoothing. Actually i am trying for about two weeks. My listing is here: ...
9
votes
4answers
948 views

Passing large list by reference

I have the following problem: I would like to control evaluation of a variable that points to a list. For example, frequently in the code I have functions of the form that are supposed to work on ...
9
votes
2answers
447 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 ...
9
votes
2answers
147 views

How to make TraditionalForm display the same in the Manipulate output as in a notebook?

I noticed that TraditionalForm does not display as nice in the Manipulate output as in normal notebook. Is there a way to make it look the same? Here is an example, ...
9
votes
2answers
2k views

Is it possible to create iOS apps with Mathematica?

I am fairly new to Mathematica and don't have much experience with other programming languages, but I can already see that Mathematica and the Wolfram language are far easier to use than most others. ...
9
votes
1answer
299 views

How can I add row and column header images to my TableForm output?

I am experimenting with the Eigenfaces algorithm and have my notes and experimental data collected in a Mathematica notebook. The result of an experimental run is a table of scores, where the smallest ...
9
votes
3answers
160 views

Implement settable properties

I am looking for advice on implementing the following. (It is possible that the answer is that it is simply not a good idea to do this.) I would like to have an object similar to ...
9
votes
2answers
544 views

Memory leak issues

I am working with noncommuting objects and basically I am using Mathematica to sort large expressions by normal ordering and simplifying them. To this end, I first create an object called ...
9
votes
1answer
132 views

Is it possible to use the global definition of a symbol as part of its new local definition set in a Block?

Consider the following expression: Block[{Print = CopyToClipboard}, doSomething[]] Now all calls to Print from ...
9
votes
1answer
463 views

GeoDirection and GeoDistance Memory Leaks: How to Recover the Memory?

The functions GeoDirection and GeoDistance have memory leaks. To see this, run the example functions below and watch as the Physical Memory Available in the Windows Task Manager, Performance tab, ...
9
votes
1answer
643 views

Workflow in the Mathematica and Workbench IDE

After visiting one of the Wolfram presentations, I started writing code for my number theory research project in Mathematica because I found it to be faster than Sage. I downloaded Workbench and ...
9
votes
1answer
186 views

How can I make CurrentValue for font characteristics pick up the font of the output not the input cell?

The command CurrentValue (documentation) allows you to access various properties of fonts, such as x-height, line height, and various measures of width such as ...
9
votes
1answer
1k views

Multi-objective genetic algorithm in Mathematica?

Is there any implementation of a multi-objective genetic algorithm for Mathematica?
9
votes
2answers
1k views

How to calculate mix of 4 colors defined in CIELAB L*a*b* model?

I have 4 colors that I converted from RGB to CIELAB L*a*b* model. How can I calculate mix of these 4 colors when I have (L,a,b) for each such color? How can I ...
9
votes
1answer
131 views

How to get control over DepthFirstScan?

Is there a way to conditionally take control the flow during a depth-first scan against a TreeGraph? I have a tree graph whose nodes are constructed as object, and there's a method ...
8
votes
5answers
371 views

How to distinguish between lists and values?

I have a (hopefully small) problem with some numerical integration algorithm, more specifically I want to integrate the imaginary part of a complex valued function, e.g. ...
8
votes
7answers
733 views

Populate an upper triangular matrix from a vector of elements

What is the best way to populate an upper triangular (or alternatively: lower triangular or symmetric) matrix from a vector of elements? This example input: ...
8
votes
4answers
475 views

How to set Block local variables by code?

I need to create a user-defined Block function where the Block variables' values are defined by code. For example, imagine I ...
8
votes
4answers
512 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 ...
8
votes
2answers
1k views

Dynamic graph visualisation using JLink/Java and GraphStream

Visualising the addition of new nodes and edges to a graph to 'watch it grow' is to something Mathematica is not suited to by default. However this type of animation really helps convey the emergence ...
8
votes
3answers
293 views

Pairwise distances of points and classification using GraphDistanceMatrix

The challenge Given $n$ points in $\mathbf{R}^3$ and a cutoff distance, $d$, I would like to determine all pairs of points that are separated by less than the given cutoff distance, $d$, and all ...
8
votes
2answers
1k views

ParallelTable and Table do not give same result

I have a question regarding the use of Parallelize. In the help one can read that “Parallelize[Table[expr,iter, …]] (which is ...
8
votes
3answers
313 views

Find the best parallel lines to a given data set

I have a set of data in an uptrend. I would like to find two BEST parallel lines to contain all the data but I don't know how to approach it, anyone can help ? Thanks.
8
votes
1answer
3k views

Mathematica Bifurcation

Continuing with the same question I have posted earlier I would like to find the equation of the stable fixed point curve using my graph, i.e. from the curve somehow find the equation for $x=f(x)$. I ...
8
votes
2answers
3k views

How to define a differential operator?

I have a linear differential operator, for instance, $L\left (\partial _{t} \right )=\partial _{tt} - 3\partial _{t} + 2$. I use it in 2 different ways: apply the operator to a function: $L\left ...
8
votes
2answers
301 views

Recursive partitioning: Is there a better way to do this?

Consider the following function, which recursively splits a list into equal length sublists (the length of the list is assumed to be a power of the second argument): ...
8
votes
3answers
262 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: ...
8
votes
3answers
551 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) ...
8
votes
1answer
140 views

CSS Selectors for Symbolic XML

Symbolic XML is a convenient way of managing XML in Mathematica, at least for casual use or small tasks. Here and elsewhere you can find examples of XML handling in Mathematica, including XSLT/XPath ...
8
votes
2answers
267 views

Cases[data,Colon[key,_]] vs. Cases[data,key:_] toward XPath, XQuery

Exploring methods to index and search tree-structured key:value pairs via named-entity index (key paths) as opposed to Position-based indexing. Using Rule as ...
8
votes
2answers
311 views

Get rational and irrational parts

Consider an expression of the form $a + b \sqrt{2}$, where $a,b \in \mathbb{Q}$. How can I extract $b$ (or equivalently $a$) from this expression?
8
votes
2answers
323 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 ...
8
votes
1answer
342 views

What is a good coding style for setting and changing application level constants?

Background: Every application has user-definable constants. The Java language has the Properties class to handle them. Question: What is a good and re-usable coding style for setting and changing ...
8
votes
1answer
315 views

Why does Mathematica choose the second function definition?

While working on a solution to this question I've come across a case where I simply don't understand Mathematica's behaviour. I've got the following definitions: ...
8
votes
1answer
171 views

The Flat Attribute, Unevaluated and the Evaluation Process

To make this question easy to follow let's give some symbols a couple attributes. Attributes[f] = {Flat}; Attributes[s] = {Orderless}; Now consider the ...
8
votes
1answer
84 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 ...
8
votes
1answer
148 views

Is it possible to write a function immune to symbol redefinitions in any Block surrounding its invocation?

Normally, semantics of symbols used in a function definition can be changed by their redefinitions in Blocks surrounding the function invocation: ...
8
votes
1answer
311 views

Is it possible to construct a function to make a poor man's Mathematica database?

I have a function that is set up to write to a database with 10-20 standard variables with 10 fields each, but the application is going to a place where database access is not available. Can ...
8
votes
1answer
406 views

Using NETLink.MathKernel.Compute() for graphics results fails with GraphPlot[]

I'm using MMA 8.0 to provide backend on a .NET application I'm writing. I am trying to use the high-level Wolfram.NETLink.MathKernel interface to export an image ...
8
votes
1answer
929 views

(Non-Convex) Polygon Union and Intersection Functions [duplicate]

Possible Duplicate: Intersecting graphics Back in 2009 I posted a question in comp.soft-sys.math.mathematica looking for a function which generates the union of two (not necessarily convex) ...
8
votes
1answer
132 views

How to assemble and disassemble a function into steps

I've watched many programmers (both novice and expert) write functions in Mathematica and have observed a common behavioral pattern. This pattern has many elements that would be automated and thus ...
7
votes
3answers
323 views

Unencoding encoded URLs in a function

Is there a built-in function for decoding encoded URLs in Mathematica? I would like to convert an encoded URL, for example ...
7
votes
6answers
437 views

How to build a list of functions

Having said that I'm no expert, I have some problems in generating a list of functions inside a loop. The functions in the list should depend on the elements of a parameters list, that are read in ...
7
votes
6answers
607 views

How can you give a Module a context and have its local variables and Modules belong to that context?

What would be the best way to give a module its own context and have its local variables and Modules belong to that context?
7
votes
3answers
896 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
5answers
419 views

Computing the average over the values of the boxes surrounding a box in a grid

Recenty,I encounter a problem described as below: I have a table that owns many boxes,and each box has a sequence like 1,2,3,4,etc.In addition,every box has a value. Now I want to make the ...
7
votes
3answers
271 views

Interactively inspecting parts of an object

There have been times when I want to find the structure of an object in order to extract some part of it. For example, extracting the x and y coordinates from a Graphics object generated by Plot. I ...
7
votes
2answers
301 views

What's the purpose of the Unique function?

As the title says: What's the purpose of Unique? I understand that it generates some unique symbol, but when and for what is it to be used? Are there applications ...
7
votes
2answers
340 views

How to get short definition of all built in Mathematica Functions?

The first post in "Mathematica Weekly Newsletter - Tuesday, December 30, 2014" really attracted my attention as I was always looking for a complete list of built in Mathematica functions with short ...
7
votes
3answers
941 views

Programming Mathematica in plaintext, i.e. no formatting, non-notebook

I'm new to Mathematica and I've just begun reading Paul Wellin's Programming in Mathematica. The book, like many other books and online tutorials, revolves around using the notebook, with all its ...