Author: Robert Hyatt
Date: 07:34:36 08/30/00
Go up one level in this thread
On August 30, 2000 at 00:31:24, Ricardo Gibert wrote: >On August 29, 2000 at 23:19:59, Robert Hyatt wrote: > >>On August 29, 2000 at 19:18:17, Alexander Kure wrote: >> >>>On August 29, 2000 at 13:58:52, Graham Laight wrote: >>> >>>>Firstly, apologies to everyone for dashing off after the last game in the WMCCC. >>>> >>>>It enabled me to get an extra day's holiday with my girlfriend, though, which >>>>was well worthwhile! >>>> >>> >>>Well deserved, Graham! >>>Thanks again for your work. >>> >>>[...] >>> >>>This game clearly showed that Fritz plays in a different league than Crafty! In >>>fact I think this was one of the best games of the WMCCC. >>> >>>Greetings >>>Alex >> >> >>My take on this game is a bit different. I do _not_ want my program to make >>such a sacrifice and then see the eval steadily go _down_ over the next few >>moves. It means one of two things for it to win such a game: >> >>1. The eval is bogus. It is saying "this is bad" when in reality "this is >>good". I don't want that sort of evaluation. > >But this is unavoidable. Otherwise computer programs would only need to do a 1 >ply search. > Not at all. It can say "I am not sure, so I think being a piece for two pawns down is bad.." But the case I was talking about is the case where a program will enter into a sac like this thinking it is almost 'even' only to see the eval dwindle over the next few moves (ie as it would have after Nxe6, and as it actually did for a few moves in the real game). >> >>2. The program was lucky. A little luck doesn't hurt. But it doesn't win >>tournaments very often. > >Again, unavoidable. Have crafty play against itself and you will still have >decisive games. The games are won due to luck, since they have the same eval. >The question is, "did Fritz make a good gamble?" I've always said luck figures into these things, to be sure. But in that case, "fritz is in a different league from Crafty" might have the opposite meaning from what Alex implied. :) > >> >>Either the eval was wrong, or it was lucky. Neither one leave me feeling like >>"fritz is in a different league than Crafty..." > >Of course, but that is pretty much how _all_ games are decided isn't it? Not for me, no. Crafty wins a few lucky games here and there, where it is down in material but some forced tactic that neither program saw comes to its rescue. It loses a few where it was significantly ahead, in the same way. But most games go just like you would expect. The eval slowly goes up, it wins material, and then the game, or the eval slowly goes down, it loses material and then the game... > >> >>I suspect white has better moves that might have justified the pessimistic eval >>Fritz had... The right program might have made that sacrifice look as ugly as >>this game made it look brilliant... > >Better moves may exist, but you have to _find_ them. The devil is in the >details. It is wrong to avoid gambling, since good gambles _do_ exist and so you >will pass up good gambles if you try to avoid them. The question is, are more of the gambles sound or unsound? If the latter, then the overall result is a weakened player. > >In reality, any eval in a non-terminal position is a gamble by crafty whether >you want Crafty to gamble or not. It is unavoidable. Crafty gambles all the >time. But not by throwing a piece away for a couple of pawns. That is a game-decisive gamble. You win if you are right, you lose if you are wrong. Most of the gambles are of the form "I think my isolated pawn is better than your backward pawn" or "I think my king is safer than yours, even though we are on opposite wings." etc... Those are not instant decisions that dictate the outcome of the game immediately.
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