Author: Ed Schröder
Date: 04:08:27 12/30/02
Go up one level in this thread
On December 30, 2002 at 05:53:16, Martin Giepmans wrote: >On December 30, 2002 at 05:30:45, Ed Schröder wrote: > >>As it seems I have completely mishandled explaining Reduction 2b and 2c, I have >>corrected things. >> >>http://members.home.nl/matador/chess840.htm >> >>Click on the blue "update" picture, it will move you directly to the changes >>made. That will be standard procedure from now on in case of errors. >> >>if (remaining_depth<=x && remaining_depth>1) then >> { if (ALPHA < SCORE + THREAT) -> do not reduce >> if (ALPHA < SCORE + THREAT + MARGIN) -> reduce depth with one ply. } >> >> SCORE : score of EVAL >> THREAT : Queen=900, Rook=500, Bishop=300, Knight=300, Pawn=100 >> MARGIN : TABLE [remaining_depth]; >> >> static int TABLE[]= { 00,00,10,15,20,25,25,25,25,25,25,25,25,25, >> 25,25,25,25,25,25,25 ........... }; >> >>The idea is, if SCORE+THREAD are not going to make it to ALPHA, but with an >>extra small MARGIN it will then reduce the depth. I can't remember the speed-up >>this reduction gave. >> >>==== >> >>Ed >> >>PS, the "faulty stuff" plus Uri's correction is maybe worth a try, who knows :) >The < in the second formula should be > ? >Otherwise the two formula's together don't make sense. >(if the first is true, the second is also true) For free-style pseudo code it is defendable, maybe in more c-code style would make it more clear? { if (ALPHA > SCORE + THREAT && ALPHA < SCORE + THREAT + MARGIN) -> reduce depth with one ply. } ALPHA=100 SCORE=90 THREAT=0 MARGIN=20 -> reduction ALPHA=100 SCORE=60 THREAT=0 MARGIN=20 -> no reduction Ed >Martin
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