Author: Ed Schröder
Date: 00:38:21 07/16/00
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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 think that knowledge about cases whan a knight cannot move and maybe trapped >is important and my observation is that knowledge=500 proably does not know it >better. > >There are cases when you need some more plies to see that the knight is trapped >by search(I saw a case when you need about 10 plies) but a good evaluation can >tell you that the knight has no square that are not controlled by the opponent >and give about one pawn panelty. > >This is only one example and there are other examples when it is important to >include big positional scores in the evaluation. > >The difference between knowledge=25 and knowledge=500 is mainly in small >positional scores and I believe that there is no difference or no difference in >the big positional scores that are the important scores. > >Uri
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