Author: Vincent Diepeveen
Date: 03:07:32 06/26/98
Go up one level in this thread
On June 26, 1998 at 01:13:38, Robert Hyatt wrote: >On June 26, 1998 at 00:44:08, Don Dailey wrote: > >>Hi Vincent, >> >>This post is not specifically for you, but your post touches on these >>points. So here goes ... >> >>Ok, it's thought experiment time! I would like to address what I call >>the "knowledge myth" concerning chess programs. I think a lot of us >>think of knowledge as a "quantity" and that simply adding more and >>more makes your program play better and better. I will argue that >>this is far from clear. >> >>Suppose your chess program was magically given INFINITE time to >>perform any STATIC evaluation function you wanted to implement, but >>everything else remained the same. Would it now suddenly become >>trivial to write a super grandmaster, Kasparov beating monster on >>modest hardware? >> >>You could do all those wonderful things you always wanted to do with >>no speed penalty, the sky is the limit. Some of you have probably >>already figured out that you could use this time to do more searching >>but let's say this is not allowed, no cheating. >> >>I can think of lots of imaginative things I might try but in the end I >>am afraid I would get only a modest improvement over what I have now >>and most of this might well be because my current evaluation is not >>free. But my point is, that we do not have a serious problem with >>QUANTITY of knowledge, although certainly more would help, especially >>if we can get it for free. The real problem is QUALITY! Does anyone >>know how to write this new evaluation function? Is it as simple as >>just adding more and more rules and somehow cramming in more QUANTITY? >>NO it's not that simple. Right now the really good programs are >>having a "law of diminishing returns" crisis. You can double the >>knowledge (whatever that really means I don't know) but don't expect >>more than tiny hand full of rating points. If you want the rating >>points, you must do BETTER knowledge, not more. It's quantity versus >>quality here. >> >>Here are some examples to make my point clear. Suppose my program >>thinks knights are worth 1/2 a pawn. I keep watching it play these >>unsound exchanges of knight for a pawn and wonder what is wrong. Is >>my program lacking knowledge or does it have BAD knowledge? With my >>infinite evaluator can you tell me what its true value should be? I >>don't think you can. >> >>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 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... > >But you might be surprised at the effect of KRP vs KR and KQP vs KQ. KRP KR is very very effective especially against Diep, as diep likes to trade to rook endings very much as it know there are big drawing chances there. However against crafty which uses KRP KR, and diep where the EGTB generator is not ready yet, this means it loses game after game sometimes just because of this (and a bad endgame evaluation which is dumber than let's say Deep Blue). In blitz generally such endgame databases simply KILL. [cut]
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