Author: Ed Schröder
Date: 14:50:24 07/16/00
Go up one level in this thread
On July 16, 2000 at 06:11:49, blass uri wrote: >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) In Century 1.2 the chess knowledge parameter by accident was cancelled. Testing the chess knowledge parameter with Century 1.2 makes no sense. That's why I used the 1.0 version. >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. You are missing the point, perhaps I expressed myself wrongly. The point is that [Chess Knowledge=500] knows more than [Chess Knowledge=100] and the fact some tactical key moves are found on earlier plies is a good proof. You can also check the increased score which I think is true for the 4 examples I gave. In the case of your Qg4 example I am not sure if [Chess Knowledge=500] helps or not. Using the maximum setting isn't a magic stick that solves everything as many many things still need to be programmed. Ed >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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