DSD

lie is a python mod­ule for com­pu­ta­tions with Lie groups, Lie alge­bras, rep­re­sen­ta­tions, root sys­tems, and more.

It’s based on the com­puter alge­bra pack­age LiE, writ­ten by M. A. A. van Leeuwen, A. M. Cohen and B. Lisser in the early 90’s. They chose to imple­ment a pro­pri­etary script­ing lan­guage as a wrap­per for all the fancy math­e­mat­i­cal algo­rithms. While this lan­guage is use­ful for inter­ac­tive com­pu­ta­tions and short scripts, python is more expres­sive and pow­er­ful — def­i­nitely what you want when explor­ing your favorite excep­tional group.

A Fun Example

Here’s an exam­ple of using lie to do a cal­cu­la­tion that’s near and dear to every high energy theorist’s heart. We’ll show how the 10 + 5bar + 1 rep­re­sen­ta­tion of SU(5) con­tains a sin­gle stan­dard model gen­er­a­tion. First we’ll fire up python and import the lie mod­ule. Con­tinue reading…

The snarXiv is a ran­dom high-energy the­ory paper gen­er­a­tor incor­po­rat­ing all the lat­est trends, entropic rea­son­ing, and excit­ing mod­uli spaces. The arXiv is sim­i­lar, but occa­sion­ally less random.

Actu­ally, the snarXiv only gen­er­ates tan­ta­liz­ing titles and abstracts at the moment, while the arXiv deliv­ers match­ing papers as well. Details of the imple­men­ta­tion are below. I’m the author, and I don’t remem­ber exactly why I decided to do this. I did already have the frame­work lying around from a pre­vi­ous project, and I swear I spent more time doing research last week­end than imple­ment­ing snarXiv.org.

Sug­gested Uses for the snarXiv

• If you’re a grad­u­ate stu­dent, gloomily read through the abstracts, think­ing to your­self that you don’t under­stand papers on the real arXiv any better.
• If you’re a post-doc, reload until you find some­thing to work on.
• If you’re a pro­fes­sor, get really excited when a paper claims to solve the hier­ar­chy prob­lem, the lit­tle hier­ar­chy prob­lem, the mu prob­lem, and the con­fine­ment prob­lem. Then expe­ri­ence pro­found disappointment.
• If you’re a famous physi­cist, keep reload­ing until you see your name on some­thing, then claim credit for it. Con­tinue reading…

[Update 7/7/09: WP-Typogrify has now merged with WP-Hyphenate, and is com­pat­i­ble with cap­tions out of the box.]

Hamish Macpher­son’s WP-Typogrify is one of my favorite Word­Press plu­g­ins. I started using it espe­cially for the Smar­ty­Pants func­tion­al­ity, which fixes “dumb quotes” and poor man’s apos­tro­phes, among other things.

How­ever, I was dis­ap­pointed to find that this func­tion­al­ity breaks Word­Press cap­tions (intro­duced in WP 2.6), which I’d rather not live with­out. Devel­op­ment on WP-Typogrify seems to have slowed — there hasn’t been a new ver­sion in a while, so I’ve taken the lib­erty of hack­ing ver­sion 1.6 to fix this incom­pat­i­bil­ity, at least so I can use Smar­ty­Pants until an offi­cial fix comes out. The adjust­ments I made are sim­ple, and I have no idea whether they’re max­i­mally robust. But feel free to

and use at your own risk. Con­tinue reading…

I should prob­a­bly doc­u­ment the real ori­gin of the The­o­rem of the Day and Phi­los­o­phy of the Day. Cof­fee and Henry David Thoreau are per­haps less involved than orig­i­nally indicated.

The the­o­rem gen­er­a­tor was writ­ten by a good friend of mine, Matt Gline, as a project for CS51: Abstrac­tion and Design in Com­puter Pro­gram­ming, which we took together as freshmen.

The assign­ment was to use LISP to imple­ment a con­text free gram­mar — basi­cally a set of rules for computer-generated mad libs. The sub­ject was what­ever we wanted. Good ones from past years include computer-generated mys­tery novel­las, course-guide reports, and per­for­mance art direc­tions. Every year there’s a con­test, and Matt’s the­o­rem gen­er­a­tor was hys­ter­i­cal enough to win him lunch at the fac­ulty club. Con­tinue reading…

New Phi­los­o­phy

Con­tinue reading…