Author: Frank Schneider
Date: 23:48:15 01/24/99
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On January 24, 1999 at 19:04:24, Will Singleton wrote: >On January 24, 1999 at 08:02:16, Frank Schneider wrote: > >>I once added recognition of pins (to the king), but it was slower and did >>influence the searchresults only a little. >> > >Frank, > >I get burned by pins more than I like. Do you have any specific pin code at >all? Yes, pins are penalized by the evaluationfunction. Part of Gromits incrementally copied und updated datastructures are attacktables FIXED16 catab[64], oatab[64]; // (for computer and opponent). If bit i is 1 in catab[p] then p is attacked by piece #i of the computer. The problem with attacktables is that calculating and copying them is expensive, therefore you have to write a lot of chess-specific code that uses them to get a return for the invested time. Having attacktables it is quite easy to a) detect pins b) calculate a penalty depending on the number of pieces attacking and defending the pinned piece c) do lots of other things (kingsafety, finding pieces that attack a square in SEE, ...) > >Will Frank
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