Author: Aaron Tay
Date: 23:41:20 04/07/01
Go up one level in this thread
On April 07, 2001 at 23:59:48, Robert Hyatt wrote: >On April 07, 2001 at 12:14:43, Uri Blass wrote: > >>On April 07, 2001 at 11:46:25, Rajen Gupta wrote: >> >>>On April 07, 2001 at 10:46:43, Uri Blass wrote: >>> >>>>On April 07, 2001 at 09:04:28, Rajen Gupta wrote: >>>> >>>>>hi; thanks for the answers: however isn't it true that the 4cd set by chess base >>>>>(endgame turbo)consists of nalimov EGTB's whereby the chess engine can actually >>>>>search for a position encoded within these tablebases as opposed to the ordinary >>>>>ones in which only when a position that is in the EGTB,is actually reached >>>>>during game play that the EGTBs kick in? >>>> >>>>You are wrong about your assumption about the ordinary ones. >>> >>>Hi uri: >>>by ordinary ones i meant ordinary EGTB (the ken thompson ones)as opposed to the >>>newer nalimov EGTB.i wasn't referring to a particular chess engine having the >>>capacity to access them in the search.it is my understanding thqt with nalimov >>>EGTB the chess engine can actually search for a position encoded within the EGTB >>>as opposed to the older EGTB which kick in only when a psoition has actually >>>been reached which is within the EGTB. >>> >>>correct me if i'm wrong >> >>I do not see a reason to assume that the thompson tablebases cannot be used in >>the search in the same way that nalimov tablebases are used. >> > >There is a big reason. Ken's compression algorithm is not nearly as good >as what Eugene uses, from a random-probe point of view. IE with Eugene's >code, a random probe doesn't have to read huge chunks of the file first, >which makes probing inside the search doable. If you use the Thompson >compression approach, probing would be horribly slow if done deep in the >search. > > > > >>The thompson tablebases did not give accurate result for part of the positions >>and it gave only correct results for positions when the strongest side could win >>but I see no reason that prevent chess programs to use the information in the >>search. > >Ken also ignored enpassant, which means 2 pawns were impossible. > > > >> >>I believe that the reason that Fritz could not use the thompson tablebases in >>the search was the fact that the programmers were too lazy to teach fritz to do >>it(they were even too lazy to tell Fritz to use the thompson tablebases >>correctly at the root). >> >>The thompson tablebases are bigger than the nalimov tablebases and nobody use >>the thompson tablebases today so this subject is not relevant. >> >>Uri > > >Nalimov == smaller & more efficient to access... How about the Edwards tablebases? Crafty used it for a time I believe..
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