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.
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.
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.
On this first day of 2015 I'm writing down some things that are important and that I wish people around me would know. There's nothing here that I haven't said before. My usual pattern is to say something and treat it as settled, because I expect everyone present at the time to remember it once they've been told. But not all of my friends have been paying attention to all of my writings for all of the decades I have been writing, and maybe at this time some repetition is appropriate. I wish I could have ten thousand readers for this and for all of my important postings. I may be lucky to get as many as ten readers. But if nothing else, the exercise of choosing what I want to say today is of some use to me personally, whether anybody reads it or not.
It's New Year's Eve in Copenhagen, and time for another update.
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。
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.
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.
Every time I think I've seen it all with regard to Danish excuses, this place surprises me. Today's excuse is tzaraath.