Search found 1215 matches

by mjlef
Fri Apr 27, 2007 9:34 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Speedup with bitboards on 64-bit CPUs
Replies: 49
Views: 36252

Re: Speedup with bitboards on 64-bit CPUs

I think it has been reported here Rybka, which Vasik says uses bitboards, runs about 60% faster on a 64 bit processor. I think the speed difference will depend greatly on what is being represented with 64 bit values. Lately, I have kept my mailbox move generation, but use some incrementally update b...
by mjlef
Mon Apr 16, 2007 12:02 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Material imbalance evaluation
Replies: 10
Views: 13561

Re: Material imbalance evaluation

Hi, I think everybody knows Kaufman's article on evaluating material, but just in case: http://mywebpages.comcast.net/danheisman/Articles/evaluation_of_material_imbalance.htm So far I haven't had any luck adding those corrections in Hamsters, but I would like to go deeper on the subject. Is there a...
by mjlef
Wed Apr 04, 2007 1:16 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Futility pruning question
Replies: 16
Views: 18008

Re: Futility pruning question

You should not futility prune if in check, the move gives check, or the move is likely to effect a score change big enough to raise the score above alpha--like making a passed pawn. If your margin of 200 covers this, then it should be good. It certainly does not cover things well enough in NOW. I ha...
by mjlef
Tue Apr 03, 2007 10:53 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: LearningLemming jumps off a cliff and dies
Replies: 15
Views: 20023

Re: LearningLemming jumps off a cliff and dies

That is good news, since the second time you write a program it always comes out better. You can restructure the data to betetr suit what you ended up doing. Ask Tord...he keeps starting from scratch and it gets better every time!
by mjlef
Thu Mar 29, 2007 6:30 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: SEE on non-capture moves in main search
Replies: 62
Views: 72063

Re: SEE on non-capture moves in main search

I'm experimenting with my move scoring and decided to test running my SEE on every move. The idea was, for non-captures, if the move hung the piece, the SEE would detect this and we could give the move a massive penalty. It turns out about 33% of moves "hang" pieces (where hanging is defined as SEE...