Though computer programming has rather little to do with computer science on the whole, most computer scientists (including me) do a lot of programming. Here's a few things that may be of use to somebody else out there. All code is released under the 3-clause (a.k.a. "revised") a BSD License unless otherwise specified.

Research

• hinton.py uses matplotlib to draw Hinton diagrams, which are a method of visualizing weight matrices (the magnitude of the weight is proportional to the area of the corresponding inner square, white is positive, black is negative). Here's a picture.
• fourregions.py implements a classic benchmark for nonlinear classifiers, the “four regions” task. Given x and y coordinates in the [-1,1] interval, the task is to learn to correctly predict the class, given this layout (where the colour of the point denotes its class).

Web / RSS

• tfd.py screen scrapes the markup on a triumvirate of popular web comics and spits out a valid RSS feed (to stdout). The author is somewhat against third-party feeds and so I do not provide a public one; this utility might be used, however, to run a private feed, accessible only to its creator, or to create a local feed.

Utility

• A lexer/scanner to read in Portable Graymap (PGM) files, the most brain-dead simple image format in the world (compile with lex or flex to generate C source code).
• A simple Python script to dump MSN logs to readable plain text from their wacky XML format.

Educational

• A bunch of Scheme procedures I wrote while learning the language for a class. Starts extremely simple and builds up to matrix multiplication.
• A k-nearest neighbours implementation in MATLAB with ridiculously detailed comments, that I wrote as a TA for CSC384. It is definitely not the most efficient implementation in the world, but the comments might prove instructive to a MATLAB beginner.

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Other People's Software

This is a handful of open source or otherwise gratis software that, because the original website is unreliable or no longer operative, I am mirroring here. I provide absolutely no warranty or support for these packages, and any use of them is bound by their respective license terms; caveat emptor. It just pains me when useful things disappear off the Internet, and this is my small attempt to thwart link rot.

• Platypus 4.2 (source code), a GPL utility by Sveinbjorn Thordarson for creating OS X app bundles from shell, Perl, Python, etc. scripts. As of this writing (June 2009), the developer's server is unreliable but you can try to access the the Platypus web page. Another mirror of the same file is at this site (as well as the the source code).
• X-Deep 4.6.5, the last freeware version of a lightweight Win32 X11 server. Simpler to install than Cygwin/X with less disk storage footprint and, in my experience, faster on older, limited hardware systems. See also Readme.txt and license.txt that come with it.