Author: blass uri
Date: 03:11:49 07/16/00
Go up one level in this thread
On July 16, 2000 at 03:38:21, Ed Schröder wrote: >On July 15, 2000 at 18:10:53, blass uri wrote: > >>On July 15, 2000 at 17:40:00, Ralf Elvsén wrote: >> >>>On July 15, 2000 at 16:58:40, Pete R. wrote: >>> >>>>To take a different tack, I'm not particularly interested in the debate about >>>>whether DJ is GM strength or not. When I can set up a position on my home PC, >>>>and it can tell me as well or better than Kasparov can what the best move is and >>>>*why*, in terms I can understand, then there will be nothing important left to >>>>do in computer chess. But that's still a long way off, past the point when a >>>>home PC can supply enough horsepower to have a program beat the World Champ in >>>>match play. Playing good enough to win and understanding chess as well as a GM >>>>are two different things. And frankly from a commercial standpoint I'm more >>>>interested in training software that can do the latter, rather than just beat me >>>>up. >>>> >>>>In terms of DJ's performance, the question I'm musing about is whether a top of >>>>the line 8-way processor general purpose computer may be sufficient to do the >>>>job of beating humanity, subject to some lucky or brilliant tweaks in evaluation >>>>code. In other words, is the matter of coming up with better positional moves >>>>in blocked positions, thwarting wing onslaughts, etc. a matter of putting in so >>>>much *more* evaluation code that an 8-way server can't do the job? DB got >>>>around this by having massive amounts of eval parameters, all done in special >>>>hardware. But the recent performances, warts and all, of top multiprocessor >>>>programs begs the question of how much more horsepower is really needed. This >>>>is simply speculation of course, like most of these topics, but only the >>>>programmers would have a feel for whether they need another 1000 eval terms, or >>>>just better tuning. >>> >>>I have looked at most of Crafty's evaluation. Let me first say that >>>this is no Crafty bashing. I like the program. That said, the chess >>>content encoded is very crude. It is heuristics which may or may not >>>apply to the position in question. None of the little pieces of evalutation >>>does a better job than an average clubplayer. It is in combination >>>with the search it becomes so powerful. Of course I realize it is very >>>hard to balance such amount of code and I would fail miserably myself >>>if I tried. I am *not* complaining. >>> >>>I think we need many more plies >>>before the program can "teach" us what a position is really about, or >>>alternatively a much more precise (and slower) evalutaion. Since Crafty is >>>playing in the same division as the best commercials, I don't expect them to >>>have much more sophisticated evaluations. If they have, it hasn't given >>>then any superiority. >>> >>>Let me take this opportunity to ask someone who knows: Has Ed Schröder >>>chosen to add "everything" in Rebel's evalution. I might have misunderstood >>>some of his statements. He seemed to be disappointed that more chess >>>knowledge could give a weaker program in comp-comp games. >> >>I think that the main reason is that bigger knowledge does not know important >>things. >> >>It may be better than the default in small things but I do not know about cases >>when there is a big difference in the evaluation of a pawn between knowledge=25 >>and knowledge=500. > >Uri, you must be kidding... :) > >Rebel knows a lot more when [Chess Knowledge] is set to its maximum. >Here are a few examples where key-moves are found 1-3 plies sooner >pure on positional grounds. Position 1 & 4 are about king safety, >position 2 & 3 are instructive about the value of pins. > >r2q3r/pp1k1pb1/3p3p/3P3n/5Bbp/2N5/PPPQN1P1/2K2R1R w - - id POS (sac); bm Bxd6!; >r2q1rk1/pp2p1bp/2n1Ppp1/2pn4/3pNP2/6P1/PPPPQ2P/RNB2RK1 b - - id POS (att); bm >d3!; >5r1k/ppp3pp/3bPqb1/8/3Pn1PP/4BN2/PP3PK1/R2Q1R2 b - - id POS (pin); bm Nc3; >r1bq1rk1/3nbppp/p2pp3/6PQ/1p1BP2P/2NB4/PPP2P2/2KR3R w - - id POS (ks); bm Bxg7; > >The list is endless. Used program Rebel Century 1.0 in case you want to check. > >Ed I will check this positions when I have time but here is a position when I was disappointed by chess knowledge=500(I used Rebel century1.2a) This is the relevant position from the game Junior6a-chess system tal: [D]r4rk1/pp1n1pbp/2p1p1p1/3nP3/2B2P1q/2N4P/PPPBQP2/2KR3R w - - 0 1 Junior blundered by 14.Qg4 and lost a pawn. The reason is that it has not trapped knight code. computers like this move. They believe that white can get the pawn back by 14.Qg4 Qxf2 15.Bxd5 cxd5 16.Nxd5 and do not understand that this line is not good because of 16...h5 17.Qg1 Qxg1 18.Ne7+ Kh7 and the white knight is trapped(it is impossible to know by evaluation that the knight is trapped but it is possible to suspect that it is trapped and give a big positional score of a pawn for it). Junior6a saw it at move 15 and did not lose the knight but it lost a pawn. Chess knowledge=500 does not help Rebel to see that 14.Qg4 is wrong. The difference in plies here should be clearly more than 1-3 plies. The question is if there are cases when chess knowledge=500 help rebel to see clearly different evaluation and not only to be faster by 1-3 plies. Are there cases when chess knowledge=500 can see that white has one pawn advantage very fast and chess knowledge=25 cannot see it even if you search more 1-3 plies? Uri
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