Author: Robert Hyatt
Date: 19:35:43 09/03/05
Go up one level in this thread
On September 03, 2005 at 19:17:49, Kevin K wrote: >On September 03, 2005 at 18:06:05, Robert Hyatt wrote: > >>On September 03, 2005 at 17:05:36, Kevin K wrote: >> >>>Hello, Dr. Hyatt. >>> >>>1 d2-d4 d7-d5 2 e2-d4 >>>1 e2-d4 d7-d5 2 d2-d4 >>> >>>These two moves are considered the same in transposition table, >>>because resulting positions are the same. >>>But, what about in book database? >>>As far as I know, Crafty does not consider these the same positions in book. >>>Why not? >>>For example, if I have only 1 d2-d4 d7-d5 2 e2-d4 e7-e6 in book and >>>if I play 1 e2-d4 d7-d5 2 d2-d4, Crafty does not find next move(e7-e6) >>>from book even though two positions are the same. >>> >>>Thank you. >> >> >>A book position is based on the parent position and the child position. That >>is, the position before the move and the position after the book. >> >>This was done to avoid a well-known transposition "bug".. > >Why do you do normal search after moves_out_of_book > 3 instead of >moves_out_of_book >= 1 in book.c? > > if (moves_out_of_book > 3) > return(0); If I have been out of book for 3 consecutive moves, there is no reason to continue checking. In very fast games, this wastes a significant amount of time, say when the entire game is played in 1 minute...
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