Author: Don Dailey
Date: 10:42:08 06/26/98
Go up one level in this thread
Hi Bob, I disagree on your disagree : >>One more example. Endgame databases are an example of PERFECT >>knowledge and most databases contain thousands if not millions of >>terms or parameters or whatever you choose to call them. And yet >>despite this massive amount of knowledge, they do not contribute more >>than a few rating points to a chess program. And this is with PERFECT >>knowledge. Most of the strength they do contribute is concentrated >>among 2 or 3 common endings. It's a whole lot of knowledge, but >>rarely used. >> > >I disagree here. KRP vs KR is a big winner. I'm not sure what you are disagreeing about. This is one of the endings that I believe is in the 2 or 3 common ones that should be covered. > I win many pawns, against >GM's and more particularly against other programs, and many of these games >end up KRP vs KR where I win when ahead, and draw when behind. A couple >of weeks ago, Crafty was playing DiepX, and in 4 successive games, 3 were >won by this endgame database. Because I won a pawn, held on to it, trading >into a won position at just the right moment. 3 of 4 there. There is hardly >a day (playing other computers) where I don't see several of these. Against >humans, no, because they break badly when they break and the game doesn't >drag on... I actually had a suspicion you would write back saying you won a large percentage of games as a direct result of some database. But instead you said you won a LOT of games with them. But I need to know what percentage of games you won. But before you tell me this, I also need to know how many of these games you would not have won without the database. This ending can be won by most programs most of the time without the database. I know this because I once asked Larry to help me cover this ending with knowledge and we discovered it was not difficult to do. I'm not saying this is just as good, the database is clearly a better way to handle this and has the advantage of knowing the game theoretic results in advance. But what I am saying is that you do not really know how many games it's actually winning for you. I don't think you can claim to be winning games left and right because of this database. I don't discount the value of databases at all, I'm for them and we have a student working on them for Cilkchess. I have to be realistic though and I don't expect anything more than a few rating points, I would say even 30 points is wildly optimistic. Think about what 30 rating points really mean. You have to pick up a half point pretty often to get even 30 rating points. A lot of games never get to endings, the ones that do usually get to ones that are draws, or easy wins where no database is needed. Now a small percentage of what is left over end up in one of our databases but most of these databases are easy wins (depending on which ones you implement of course) and the program again doesn't really desparately need them (I don't need rook vs king.) The ending BNvsK is hard to win without specific knowledge or a database but it occurs so rarely that I doubt it's worth more than a single fraction of a percent in rating. Finally you get to the interesting endings that occur frequently compared to other endings (but still not very frequently) where you must win or draw and it's not completely trivial. Still most programs will manage to win or draw them. Your example is a case in point, a little knowledge can win this ending (most of the time) without needing the database. Bob, All of my discussion above assumes the current state of the art in endgame database technology. If it was possible to cover every single 6 and 7 man database, then I think we would have a real breakthrough. Programs would suddenly be 40-80 rating points stronger and opponents would be pressured to avoid simple endgames and indirectly more complex ones. Long live "brute force"!! >>There will quickly come a point when the bad knowledge that ALL our >>programs have will place a bound on its possible strength (given a >>certain amount of hardware.) Learning lots of rare endings and how to >>play them will help in tiny incremental ways but never make up for the >>other problems that are more QUALITATIVE. >> >>Saying Deep Blue or any other program has a billion parameters in it's >>evaluation function doesn't say much of anything about how good its >>evaluation is. >> >>Bob makes a strong case that Deep Blue is not limited to simplistic >>evaluation just because it is implemented in hardware and in fact may >>contain more terms than any other program. This is great and I'm all >>for it, wish I had it too. But it's really hard for me to draw the >>conclusion that it MUST be better because of this. This is an issue >>that must be considered separately I consider the term count a minor >>point although not totally irrelevant. (Don't blast me Bob because I'm >>not saying Deep Blue sucks either, I certainly appreciate the point >>you are making with Vincent that hardware evaluation does not equal >>STUPID program.) > > ><blaster holstered> :) > >I have no idea of a way to prove that a bigger eval is better, but I'd >certainly bet that it is no worse, unless it's written by dummies of >course... My point exactly. I don't have a problem with more and more knowledge, I'm just saying the real problem is in the engineering of this knowledge. I think the bottleneck is this. - Don
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