Author: Robert Hyatt
Date: 19:14:02 04/04/03
Go up one level in this thread
On April 04, 2003 at 15:06:37, Russell Reagan wrote: >On April 04, 2003 at 14:57:50, Keith Evans wrote: > >>What do you think you will gain by excluding certain elements? > >I have heard people discuss the drawbacks of including the fifty move counter in >the past. I'm not sure of the details though. > >As far as an example, try this: > >[D] rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1 > >The en passant square is e3. You should not have an EP target there. There is _no_ EP possibility. Setting e3 is bad, because if you move a knight out and back, then in your scheme _that_ position won't have an ep square, and the hash won't match. You should only set an ep target if a pawn advances two squares _and_ there is an enemy pawn on the right squares on either side of it, otherwise no ep status should be kept. > If you did a large search from this position, and >then encountered it again without the ep square set, then you won't find it in >your transposition table, even though the en passant square being set has >nothing to do with the score of this position. If you didn't hash the ep square, >you would get that large search again here for free. Maybe this is something >that partition search addresses. I'm not sure.
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