Author: Robert Hyatt
Date: 07:47:22 08/21/99
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On August 21, 1999 at 10:19:06, William Bryant wrote: >How do programs evaluate passed pawns in the search to trigger a passed pawn >push extenison. I noted in Crafty's code that it check to see if a pawn push is >a passed pawn, and the pawn won't be immediately captured, and then searches >deeper. > >What stratigies do programs use to keep track of passed pawns? In a bitmap program it is trivial and needs one AND operation to determine that a pawn is passed. In Cray Blitz, we incrementally updated a vector that identified which pawns were passed, and did a similar inexpensive test there. I'm not sure this is even a significant extension, to be honest. > >Are these updated in makemove and takeback functions or do you call an >evaluate-for-passed-pawns function in the search to see if things have changed >since the last pawn move? > >What gains in the search does a passed pawn push extension provide? good question. I did it in Cray Blitz, so I kept doing it in crafty. I'm not sure it is worth a thing. > >Thanks in a advance. > >William >wbryant@ix.netcom.com
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