Jeff Leon's Partition Backtracking code is GPL'd

I'm at the IMA coding theory, complexity and communication conference this week. (I'll post pictures somewhere later.)

One problem I've been trying to solve is to try to contact Jeffery Leon, a mathematician at UIC who wrote a number of programs using a very difficult combinatorial technique called "partition backtracking". This collection of programs, written in C in the 1980's, will compute automorphisms of designs, linear codes, and matrices. The program Leon wrote does some hard coding theory and combinatorial computations quite fast. The issue is that it does not have an open source license. I think it was written during a time when no one worried about such things. I have tried over the years emailing and calling Leon, but no responses. (BTW, many people have told me that Jeff is a very nice guy but you have to physically talk to him, as opposed to writing.) These days, no one will maintain it unless it has some sort of open source license (such as the GPL or the MIT license or the BSD licence ...). If this is not done, the code will die. Why? Well, bugs have been discovered (some serious, some not) and no one will spend the time to maintain someone else's code. There are many people who are willing to maintain, on volunteer basis, open source software, as part of a community effort though. Also, the code is hard to read, which only compounds the problem.

I happened to ride the airport shuttle to the hotel with Vera Pless, the great (now "retired" from UIC, though she still directs several students) coding theorist who is also visiting the IMA, and told her the problem. When we were dropped off we went our separate ways. Then, the next day we happened to meet at breakfast and she told me to call Steven Smith (the finite group theorist) at UIC and tell him the problem. I sent him and email and he almost immediately responded that he would sit down to talk with Jeff Leon about the situtation. As a result of Vera and Steven's help, Jeff just sent me a very nice email saying, in particular:

I, Jeffrey S. Leon, agree to license all the partition
backtrack code which I have written under the GPL
(www.fsf.org) as of this date, April 17, 2007.

This is great news!