Author: scott farrell
Date: 16:33:04 01/12/04
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On January 12, 2004 at 13:05:38, Robert Hyatt wrote: >On January 12, 2004 at 10:24:59, scott farrell wrote: > >>On January 12, 2004 at 05:52:07, Tord Romstad wrote: >> >>>On January 11, 2004 at 21:18:30, macaroni wrote: >>> >>>>I have recently been fiddling arround with some passed pawn code, however I just >>>>can't seem to get it working very well. Can you give me an idea of what sort of >>>>values you give different types (in different stages) of passed pawns? >>> >>>Here is a rough description of what I do: >>> >>>Start by giving the passed pawn a bonus depending on which rank it occupies. >>>You then adjust this bonus depending on the placement of the other pieces >>>on the board. Some examples: >>> >>>Protected passed pawns and passed pawn duos are especially dangerous. >>>Adjust the bonus up if there is a friendly pawn beside or diagonally >>>behind the passed pawn. >>> >>>Adjust the bonus up if there is a friendly rook behind the pawn, and down if >>>there is an enemy rook behind it. >> >>this is where you need to be careful if you have a pawnhash, you cant hash in >>other pieces :) you have to put it into the rook/king eval instead. >> >>Scott > >SSSHHHHHHHHhhhhhhhhhh!!!!!!!! > >Everybody needs to debug _that_ problem at least once. Some of us more >than once. :) Tords answer was just to hash where the passers are. What do you do in crafty? I know I just just asked in another part of this thread, but this seemed more appropriate. I am thinking of hashing in the number of wach type of piece or something, that doesnt change too much I dont think, obviously you can hash the position of the pieces, as you would increase the number of unique hashes too much. Scott > > >> >>> >>>A passed pawn is usually more dangerous if it is supported by a king. >>>Increase the bonus if the friendly king is close, especially if it is >>>somewhere in front of the pawn. Likewise, you should increase the bonus >>>if the enemy king is far away. In rook endgames, it is probably a good >>>idea to further increase the bonus if the enemy king is cut off by >>>a rook (I don't do this yet, but I plan to add it in the near future). >>> >>>Passed pawns are most dangerous if they are able to advance safely. >>>If the passed pawn is blocked by an enemy piece, adjust the bonus down. >>>If it is unblocked, increase the bonus if your static exchange evaluator >>>decides that it is safe to push the pawn, and reduce the bonus if it is >>>not safe to push it. >>> >>>Tord
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