Author: Uri Blass
Date: 11:24:18 09/06/03
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On September 06, 2003 at 14:02:25, Will Singleton wrote: >On September 06, 2003 at 13:47:24, Uri Blass wrote: > >>pawns are obvious but the question is if you store also >>1)side to move >>2)king squares >> >>both 1 and 2 may be important for evaluation of unstoppable passed pawns. >> >>Uri > >I modify the key based on king positions, endgame status, and total material. I >don't need side-to-move because promos are handled outside of pawn hash. I >recently added the material, slows it doen a bit but I think it's more correct >for evaluating passers. > >Will Thanks. I will probably as first step modify the key only with pawn moves. I do not plan to store evaluation there inspite of the fact that today part of my evaluation is dependent only on the pawn structure because I will probably modify it later and I believe that the expensive part is not the evaluation but the need to update information every make move and unmake move that change the pawn strcuture. for example I have things like openpawns[LIGHT]=pawnBB[LIGHT]&~FillDownBoard(allpawns>>8); openpawns[DARK]=pawnBB[DARK]&~FillUpBoard(allpawns<<8); passedpawns[LIGHT]=openpawns[LIGHT]&~FillDownBoard(pawnattacks[DARK]); passedpawns[DARK]=openpawns[DARK]&~FillUpBoard(pawnattacks[LIGHT]); I guess that it may be better to use the pawn hash to remember the bitboard of the passed pawns of both sides to I can save the calculation of passedpawns and openpawns that I do not need to do every move(I evaluate every position in the tree so I need the information and cannot decide to calculate it only in the leaves). I am not sure if remembering bitboards of passed pawn in the hash is a good idea and it may be better to start by remembering number of passed pawns and in a lot of cases it is 0 so I do not need to continue to store squares of passed pawns. Uri
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