Author: Chris Carson
Date: 07:34:04 07/29/99
Go up one level in this thread
On July 29, 1999 at 10:28:37, Robert Hyatt wrote: >On July 29, 1999 at 10:23:58, Robert Hyatt wrote: > >>On July 29, 1999 at 09:46:58, Chris Carson wrote: >> >>>On July 29, 1999 at 09:29:32, Robert Hyatt wrote: >>> >>>>On July 29, 1999 at 08:25:58, Chris Carson wrote: >>>> >>>>>On July 29, 1999 at 07:16:32, Amir Ban wrote: >>>>> >>>>>>On July 28, 1999 at 18:16:24, Dann Corbit wrote: >>>>>> >>>>>>>On July 28, 1999 at 17:50:51, Kristo Miettinen wrote: >>>>>>> >>>>>>>>The position is the opening array, all pieces in their initial positions. The >>>>>>>>explanation about the eight pawns makes sense, intending to steer Crafty into >>>>>>>>open waters (on the assumption that the opponent is human?) >>>>>>>> >>>>>>>>I was looking into this on a whim, as I use the advantage of White in the >>>>>>>>opening position as my quantum of positional value (on which scale the value of >>>>>>>>a pawn is 6 quanta for me). >>>>>>>Here is the C.A.P. record for that position. >>>>>>> >>>>>>>rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - acd 15; ce -7; pv e4 e6 Nf3 >>>>>>>Bb4 Nc3 Ne7 Bc4 Nbc6 O-O O-O d4 Bxc3 bxc3 Na5 Bb5; pm e4; id "C.A.P. 4028"; >>>>>>> >>>>>>>I bet you never knew crafty was French. >>>>>>> >>>>>>>Crafty thinks it is behind by 7 one hundredths of a pawn. This is obviously >>>>>>>conservative because white has a tempo at least. But I don't think that it is >>>>>>>grossly inaccurate. >>>>>> >>>>>>A correct evaluation is one that matches the winning percentages of the >>>>>>position. I think white has about 54% in serious play, and if so the evaluation >>>>>>should be about +0.20. >>>>>> >>>>>>Amir >>>>> >>>>>Amir, >>>>> >>>>>Interesting point. If I read you correctly, the "Evaluation" should match >>>>>the winning changes. This is not the way most programs "Evaluate" a position. >>>>>Granted that a higher "Eval" by a program should mean a higher "Chance" to >>>>>win, it is normally not a "Percentage" based on results. >>>>> >>>>>I have thought that this might be a better method of "Evaluation", some >>>>>programs do use a "Percentage" (Crafty) for opening book moves, but not >>>>>for middle game or end game positions. >>>>> >>>>>Any thoughts on how to incorporate "Percentage" into the "Evaluate" function >>>>>of a program (knowledge)? Perhaps a "Percentage" "Evaluation" for positions >>>>>and endgames as a part of the learning (Crafty might be able to do this) >>>>>would be useful. Any comments? >>>>> >>>>>Best Regards, >>>>>Chris Carson >>>> >>>> >>>>I disagree. Evaluations are not 'absolute' any more than FIDE Elo ratings are >>>>absolute. The correct evaluation is the one that lets you _win_ 54% (or better) >>>>of the games from the opening position. Whether the starting score is +1.00 or >>>>-1.00 is immaterial so long as you choose the best move(s) by using those >>>>scores... >>> >>>I agree with you, this makes the evaluation relative to the program/version >>>that is doing the evaluation, thus a +0.3 may have a different meaning >>>for program x than for program y, but is irrelevant as long as the >>>best move is choosen by the program using the score. >>> >>>Best Regards, >>>Chris Carson >> >> >>right.. ie a good eval could produce -1, 0 and 1 and play using those scores >>just so they are right. That program could also use -1001, -1000, and -999 >>and produce the same result... > >I should have added that I have seen _many_ positions where two GMs can't agree >on which side is better, but _both_ agree on the best move. So even humans have >this 'issue'. > >It would be nice if all programs agreed on what +.20 means, but that is _very_ >unlikely. And is the reason that in computer chess games, frequently _both_ >programs will think they are better, or they will both think they are worse. > >As Einstein said, "everything is relative, my friend" > >:) Well said. :) Best Regards, Chris Carson
This page took 0 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.