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Subject: Too Large Positional Contributions to Score

Author: Stuart Cracraft

Date: 20:29:31 03/07/99


Crafty seems to have a Scale_Up/Scale_Down factor and I'm curious
if Bob would talk a little about this. Seems costly to add a memory
reference and a division (?).

For example, seems like Bob has chosen to ScaleUp/ScaleDown fairly
large contributions such as

   weak back rank
   bishop pair
   certain rooks on open files
   rook on 7th
   protected passed pawns

based on the side's material.

Are there alternatives to controlling the "bloating" of the positional
part of the evaluation that aren't so computationally expensive? I know
there are very few of these compared to all the terms in Crafty so the
cost isn't a big deal (probably.)

One I considered was going from centipawns to millipawns and then working
backward looking at just those things that should be big (king safety)
and sizing them accordingly letting them bloat to a certain degree beyond
a pawn.

--Stuart



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