Author: Michael Henderson
Date: 12:28:07 08/07/04
Go up one level in this thread
On August 07, 2004 at 13:50:46, Stuart Cracraft wrote: >On August 07, 2004 at 13:47:41, Dan Honeycutt wrote: > >>On August 07, 2004 at 13:40:16, Dan Honeycutt wrote: >> >>>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. >> >> >>I should add I also do: >> >>if (mvv_lva + standpat + margin >= alpha) keep_capture_and_skip_see; >> >>mvv_lva is victim value - attackor value. >>Dan H. > >Dan - thanks for the input. What value of standpat do you use? >(Assume the see() routine does all its internal standpat >in its minimax.) > >Stuart Are you using SEE to order captures in the non-qsearch?
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