Author: Robert Hyatt
Date: 07:28:34 01/22/00
Go up one level in this thread
On January 22, 2000 at 06:01:51, Amir Ban wrote: >On January 21, 2000 at 22:54:36, Robert Hyatt wrote: > >>On January 21, 2000 at 17:22:08, Amir Ban wrote: >> >>>On January 21, 2000 at 15:08:16, Robert Hyatt wrote: >>> >>>>On January 21, 2000 at 13:56:40, Tom Kerrigan wrote: >>>> >>>>>On January 21, 2000 at 11:44:22, Robert Hyatt wrote: >>>>> >>>>>>It would run so much slower it would get killed tactically. Remember that their >>>>>>king safety included not just pawns around the king, but which pieces are >>>>>>attacking what squares, from long range as well as close range. Which pieces >>>>>>are attacking squares close to the king, etc. That takes a good bit of >>>>>>computing to discover. >>>>> >>>>>I realize that it takes a good bit of computing to discover. But I doubt it >>>>>takes so much that it's prohibitive. There are very successful micro programs >>>>>with extremely expensive evaluation functions, e.g., MChess and the King, and to >>>>>a lesser extent, HIARCS and Zarkov. These programs all reportedly have terms >>>>>similar to the ones you describe. I seriously doubt that the DB evaluation >>>>>function is an order of magnitude more complex than, say, MChess's... >>>>> >>>>>-Tom >>>> >>> >>>Add Junior to the above list. >>> >>> >>>> >>>>But they don't take the time to find out which pieces are attacking squares >>>>around the king "through" another piece. IE a bishop at b2 attacking g7, but >>>>only if the Nc3 moves. Or only if the pawn on d4 or e5 moves. That gets very >>>>expensive computationally. DB gets it for nothing. I think it would slow me >>>>down by a factor of 100 or more, depending on how far I wanted to take it... >>>> >>>>That might make me more aware of king attacks, but it would hide many plies >>>>worth of tactics since a factor of 100 is over 4 plies. Only a wild guess >>>>of course on the factor of 100, but since the eval is done at every node in >>>>the q-search, this is probably within an order of magnitude or two of the >>>>real answer. >>>> >>>>I can guarantee you it is more complex than the above evaluations. And I don't >>>>even know all the things they evaluate. One new idea mentioned in Hsu's book >>>>was the concept of "a file that can potentially become open" so that you put >>>>rooks on that file, even though you can't see exactly how you are going to open >>>>it within the 15 plies + extensions they were searching. "Potentially open" >>>>takes a lot of analysis on the static pawn structure. I do some of this >>>>pawn structure analysis myself, and even with pawn hashing it slowed me down >>>>significantly when I added it a year+ ago to better handle/detect blocked >>>>positions. >>>> >>>>Remember that they claimed about 8,000 static evaluation weights in their >>>>code, this reported by someone that went to a DB talk by Murray Campbell. >>>>8000 sounds like a big number... >>> >>>It's big, but what does it really mean ? Some of it must have been piece-square >>>tables for some features that were downloaded from the hosts, and that's >>>hundreds of entries per feature. >>> >>>Besides, where is all this sophistication showing up in the DB & DBjr games ? >>>Forget the numbers, whatever they mean. Show us the positions & moves. >>> >>>Amir >> >> >>It would seem that the _results_ would speak for themselves. Who else has >>produced results like theirs? > >There is no difference between DB and DBjr in this aspect, and DBjr was >according to its games an unremarkable machine with unremarkable results. > >Amir Which GM players beat DB Jr in a match? They played _many_ such matches at conferences all over the world. I _never_ saw it lose a game in the three matches I saw it play against GM players. One against Byrne. The others I didn't really know (IE I wouldn't recognize Dlugy if I bumped into him, although we have chatted a lot on ICC). And you say "no difference between DB and DBJr" which I agree with. But _I_ remember a significant match DB won (the last match it played.) I would not call that "unremarkable"... Until everybody can do it...
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