Author: Alessandro Damiani
Date: 05:58:33 01/02/03
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On January 02, 2003 at 08:21:51, Uri Blass wrote: >This trick is from Rebel programming stuff: > >MARGIN = 3.00 // 3 pawns safe-guard value > MARGIN + highest hanging piece value // Queen=900, Rook=500 etc. > MARGIN + 9.00 when own_king_was_in_check_before_make_move > MARGIN + 6.00 when the opponent can promote the next ply > if (SCORE-MARGIN > BETA) -> return TRUE > else return FALSE > >1)Why score-margin>beta? >I think that score+margin<alpha is more logical. > It is a static null-move: eval(position) - threats(opponent) >= beta The value threats(opponent) contains the highest hanging piece of the side to move. >If the score of the side to move is already bigger than beta I return beta >except special cases(like a case when the king is in check) > I remember Ed having said once in CCC that his quiescence search is more complex than a simple capture search. I assume he treats hung pieces in quiescence search. And to save search effort he uses this static null-move, I guess. Alessandro
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