Author: Uri Blass
Date: 16:26:26 06/30/04
Go up one level in this thread
On June 30, 2004 at 17:35:46, Dan Honeycutt wrote: >On June 30, 2004 at 17:01:16, Uri Blass wrote: > >>On June 30, 2004 at 15:10:51, Robert Hyatt wrote: >> >>>On June 30, 2004 at 02:58:11, Mig Greengard wrote: >>> >>>>For storage space considerations, some impractical and unnecessary bases have >>>>been left out of the DVDs. >>> >>> >>>Again, kpppk is not that impractical. Particularly when all 3 pawns end up on >>>the same rook file... >>> >>>But it really doesn't matter whether the ending is easy to win or not. What >>>matters is to stop searching as soon as possible along a path where the result >>>is known. having _all_ 5 piece tables makes that happen. Missing files are >>>less efficient, period... >> >>Based on my knowledge yace does not use 4 vs 1 tablebases. >> >>I suspect that it may be cheaper to use static evaluation in >>most 4 vs 1 positions to end the search and not to call tablebases. >> >>I suspect that a simple rule that there is a mate in at most 20 moves >>if the following conditions even in 8 vs 1 and not only in tablebases position >>may be correct(I did not prove it but I cannot think now of a negative example): >> >>1)the side to move has at least one rook or one queen >>2)the opponent has only king >>3)the side to move does not control all the squares near the opponent king(to >>prevent forced stalemate in the next move). >>4)in case of a rook the rook controls at least one square that the king does not >>control(to prevent a possible problem of white rook at h8 white knights at h7 g8 >>and black king at g7). >> > >That's a lot of conditions compared to: if (pieces <= 5) Yes but it can probably help also when number of pieces is 6 or 7 I do not use it today but there is one if that usually does not happen (if the opponent has only king and maybe it is possible to generalize it also to more cases and be sure of win in case of big material advantage) I do not think that one if that does not happen in big majority of the cases is a problem and it may make the search slightly faster by not wasting time on probing tablebases. >Looks like you could spend more time deciding if a probe is useless than if you >just went ahead and probed. > >Dan H. Not to me because probing the tablebases takes time. Uri
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