Author: Joseph Ciarrochi
Date: 23:47:55 01/04/06
Go up one level in this thread
Perhaps another way to put rybka's preference (which is consistent with what kurt said): Rybka prefers piece activity over pawns (more so than other programs) I wonder if any other programs are like this (perhaps Junior?) best Joseph On January 05, 2006 at 02:27:18, Joseph Ciarrochi wrote: >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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