an open source chess engine under the GNU General Public License , written by Bruce Moreland, written for educational purposes. It has a decent search (null move pruning, hash tables) but a rudimentary evaluation .
Bruce on Gerbil :
- It is using 0x88 move generation. The function is something under 200 lines long, which seems big, but there are a lot of comments and there's some repeated code.
- It is using vanilla windowed alpha-beta with no PVS or anything like that, and I plan to keep it this way, since that is clear and performs acceptably.
- It has a check extension. I think that is enough for now. I may try to do some pruning in the quiescence search, which uses MVV/LVA. I don't plan to write a static exchange evaluator.
- This is already a more or less fully functional winboard engine, an effort that consumed a whole bunch of time, not that Mann's standard is hard to write to. I just had to spend a lot of time messing with threads.
- Bruce Moreland's Gerbil by Ricardo Gibert, CCC, June 09, 2001
- Question about Gerbil by Artem Pyatakov, CCC, July 11, 2001
- Re: Ferret/Gerbil question by Bruce Moreland, CCC, September 21, 2001