Author: Robert Hyatt
Date: 07:11:16 12/13/98
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On December 13, 1998 at 08:18:34, Matthew Herman wrote: >On December 13, 1998 at 00:22:27, Robert Hyatt wrote: > >>On December 12, 1998 at 20:09:19, Matthew Herman wrote: >> >>>I recently compiled the tablebases for Crafty 16.1 (eugene nalimov format). Then >>>I created the crafty.eng (with the winboard.eng). Then I showed it a KBNK >>>position .. great it found the stuff from the tablebase.. then I showed it a >>>KRKB position and it didn't!?!?! what gives?? Please shed further light.. thanks >>> >>>P.S. This also happened on winboard.. >>> >>>Matt >> >> >>do you see files krkb.nbb and krkb.nbw in the directory? If not, that >>is the problem... > >Yes, I generated all of them into that folder.. and I do see it. Also KRKN >doesn't work either. It's that some work and some don't Just a minute... I forgot about something. Check your log.nnn files for games like KR vs KN. Look at the top, before the start of the search, to see if you see the message "drawn at root, trying for a swindle." that means this is a known tablebase position, that with best play it is a draw, but crafty has a material advantage. Rather than just playing any move that leads to a draw, based on randomly which move it searches first, which might well choose RxN as the move to play, even if KxR is the reply. This "swindle" mode does a normal search instead, but *only* considering the moves that lead to a draw.. which lets it make the draw as difficult as possible for the opponent. IE ie KRP vs KR, many are draws, and in choosing a position from the tablebases with a score of 0, it might give up the pawn and make the draw trivial. Now it holds on to the pawn as long as possible to give the opponent a chance to make a mistake and take the draw into a won position for crafty... Bob
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