Mountain-climbing addresses for code lines

Wednesday 25 November 2015, 03:59

I found an interesting problem while working on a test case generator for the Tsukurimashou Project. The thing is that I'd like to assign an identifying code, which I will call an address, to each line of code in a code base. It's to be understood that these addresses have nothing to do with machine memory addresses, and they need not be sequential; they are just opaque entities that designate lines of code. Anyway, I would like lines of code to keep the same addresses, at least probabilistically, when the program is modified, so that when I collect test information about a line of code I can still keep most of it after I update the software.

Notes on notes on the plane

Sunday 2 August 2015, 04:09

I have posted a detailed set of notes (PDF file) describing the theory behind my Black Swan Suite, detailing the endless chase of Elmer and Daffy across Penrose, pinwheel, and other nonperiodic tilings of the plane. Fans of music and computational geometry may find the document interesting. At the very least, it was fun to typeset.

On academic freedom and fearing one's students

Friday 12 June 2015, 11:15

This was originally a Facebook comment, to one of my friends who had posted one of the original articles there, but a lot of other people in my circles are re-sharing the same articles, more general distribution of these comments is appropriate, and anyway Facebook is an untrustworthy platform. So, here's a repost. For necessary context, see the earlier articles from Edward Schlosser and Koritha Mitchell. Both of these articles have received a whole lot of circulation in the last few days, but I'm not sure they've received enough serious attention.

Matthew, Rued Langgaards Vej 7, versus the Appliances

Wednesday 31 December 2014, 13:16

It's New Year's Eve in Copenhagen, and time for another update.


Friday 5 December 2014, 23:15

数学と理学ではLaTeXが有名です。 論文を書ければいつもLaTeXを使っています。 でもLaTeXではいろいろな文書ができます。 今日LaTeXとlilypond-bookで音楽の書くことを見ましょう。


これはTeX & LaTeX Advent Calendar 2014に僕の寄贈です。

New apartment

Sunday 2 November 2014, 02:07

As I start writing this, it is the evening of November 1 and I am sitting in my new apartment on Hallandsgade, Amagerbro, Copenhagen. It'll probably be the 2nd before I can post it, because I don't have the Net here. It sure looks like Rabbi Schlomo Yitschaki was dead right about the tzaraath of houses. Now I kind of want to read the rest of his many volumes of commentaries on Jewish religious law.

Cycle-maximal triangle-free graphs

Thursday 30 October 2014, 12:16

In January of 2011, I had recently arrived at the University of Manitoba to work as a postdoc with Stephane Durocher. One of the first things he asked me to do was find out how many cycles there are in an n-dimensional hypercube graph, for general n. At the time, he and I both assumed that that meant spending maybe half an hour in the library looking up the answer.

Since then it's been more than three years; thousands of lines of computer code and months of CPU time; we added two more co-authors; we didn't solve the original problem, and didn't completely solve the other problem that we ended up working on, either; but here's a journal paper, anyway, and I think it's pretty interesting. The official definitive version will be free to access until mid-December and then will go behind Elsevier's paywall; the authors' accepted manuscript on arXiv is permanently accessible.

Read the paper if you're interested in the math details; in this entry I'm going to try to tell the story behind the paper, in relatively non-mathematical terms. I'm hoping it'll be of interest to my Web log readers and give you some idea, because I often get asked this, of what I actually do at work.

Days since last Biblical plague: 0

Wednesday 15 October 2014, 11:49

Every time I think I've seen it all with regard to Danish excuses, this place surprises me. Today's excuse is tzaraath.

False negative

Monday 6 October 2014, 12:26

I. Fukurou

Bank Account Man

Saturday 4 October 2014, 13:23

I've been in Denmark just over a month, and I'm pretty stressed. This update is going to be somewhat disconnected. You can get some idea of what my experience has been like by watching the famous Bank Account Man commercial.