Author: Robert Hyatt
Date: 07:28:37 07/29/99
Go up one level in this thread
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" :)
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