Author: Dan Honeycutt
Date: 10:40:16 08/07/04
Go up one level in this thread
On August 07, 2004 at 13:00:31, Stuart Cracraft wrote: >So I heard a lot about SEE from a lot of people >and was fortunate enough to receive some good code >from Alessandro. I implemented and tested it with >many test cases and in all cases it gave the >expected return from the exchange ok. > >Then with some other help I implemented this in >the capture search. > >This program has some things that make SEE() not >give a good result, in fact slightly worse (fewer >nodes in same time) -- no speedup. > >1) evaluator is material and pc/sq lookup only >2) routine to find attackers/defenders (to give to see) > is not much faster or slower than makemv() >3) I order all moves partly with MVV/LVA but do not > discard directly on that unless the alpha/beta/pvs > says to disard/cutoff. > >With these, the program did not speedup with SEE >and slowed down. The program is PVS with null move. > >So that is the story -- I will leave the code in >for a future day and future need. > >If someone with #1 and #2 got a good speedup from SEE, >let me know. I am doing something wrong in that case. >Or if you think there is some other way SEE can be used >advantageously, let me know. Currently I only have it >in the capture search since that's where I heard it had >the most effect. > >Stuart Stuart: What captures are you discarding in qsearch? ie if (see < 0) discard_capture; if (see + standpat < alpha) discard_capture; if (see + standpat + margin < alpha) discard_capture; You may want to tinker with this some. For me the third one with a margin of a pawn or 2 works best. Dan H.
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.