Author: Dann Corbit
Date: 13:24:53 12/28/05
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On December 28, 2005 at 16:03:47, David Dahlem wrote: ><snip> > >>If you have a bitboard program, there is a way to get really cheap mobility >>scores. > >Could you elaborate on this method? Precalculate for every ray, based on the bit pattern on that ray. Move generation is also helped by this idea (both for capture/promotion and non-capture). consider this epd string: [D]4k3/1n6/8/pR5b/1P6/1n6/1N6/4K3 w - - For the rook's row, we have 1x000001 ( the x is because we ignore the square he sits on, he can never attack or defend that.) For this simple case, the non-captures are the zero squares and the captures are the non-zero squares anded with the opponent chessmen mask. Regardless of what the chessmen are, there are 5 non-captures and 0,1,or 2 captures depending on whether the 1 bits are friend or foe. For the column we have 010x1110. There is one non-capture and 0,1, or 2 captures depending on whether the nearest one bits are friend or foe. You get the idea.
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