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Subject: Bitboards !! :)

Author: Tony Werten

Date: 23:50:35 06/30/04


Hi all,

although I like the principle of bitboards, it really bothers me that I can't
seem to find a decent/fast way to evaluate weighted safe squares.

Suppose I want to (simple) evaluate a rook, I generate a bitboard with all
reachable squares and mask off the squares attacked by lower pieces (that's no
problem).

(This doesn't exacly generate safe squares, only the ones that aren't attacked
at all by opponents pieces are, for the remaining squares one would need a SEE,
but that's not the point )

Now I can use this bitboard ( say rook on e4 ), mask the rank state, and look in
a precomputed table how this rankstate scores on an e rank. No problem.

But how to do the files ? If I use the rotated board, I need to have the
opponents attackboard in this rotated board as well, wich would be very costly
to compute (ie also for the bishops,queens ) and very complicated.

Any ideas ? Am I missing something ?

BTW, doing a popcount isn't a solution, since it violates the elegance of
bitboards ( and is slow ?)

Tony



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