Author: Joseph Ciarrochi
Date: 23:27:18 01/04/06
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yes, you may be right. Maybe rybka is focusing on the open F file rather than missing pawn. I should note that rybka also values the pawn less if you remove the d pawn, c pawn, A pawn, or g pawn, so it does not seem specific to the f file. all following evaluations at depth = 14 d2 missing Rybka = -.11 fritz9 = -.37 c2 missing Rybka = -.17 fritz 9 = - .64 g2 missing rybka = -.17 fritz 9 = -.58 a pawn missing Rybka -.07 fritz 9 - .32 It looks like the difference could be specific to the static evaluation of the pawn, although you are right there could be other interpretations. I ran a shootout of the case when the f2 pawn is missing (is involves engines playing themselves at plys ranging from 3 to 11). White only wins 35 % so far (32 games), so I think rybka underestimates how bad the position is for white. (this of course is an artificial situation and may say nothing about how rybka handles real situations) best Joseph On January 05, 2006 at 02:04:53, Kurt Utzinger wrote: >On January 05, 2006 at 00:39:01, Joseph Ciarrochi wrote: > >>Rybka may have the greatest disdain for pawns of any other program. >> >>try this experiment out. Go to the start position of the chess board and remove >>the f2 pawn (as is typically done when a gm gives pawn odds). >> >>Here are the evaluations of different engines at depth of 15. Can you figure out >>which engine is not like the others? >> >>Rybka = -.26 >>fritz9 = -.78 >>fruit 2.2.1 = -.70 >>Aristarch = - .96 >> >>Rybka seems to treat pawns with utter disdain. I wonder what would happen if you >>lowered the pawn value of the other engines to , say .50 or .75? >> >>(I know it is not this simple and all the engines will consider the pawns in the >>context of the position, but still, i find this amazing). >> >>Maybe pawns really are only with .75 in many positions >> >>best >>Joseph > > Hi Joseph > You conclusion may also be completely wrong. It is > possible that Rybka gives a higher bonus than other > engines for the open f-file. > Best regards > Kurt [http://www.utzingerk.com]
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