M Winther wrote on Fri, Apr 29, 2011 06:45 AM UTC:
It is very easy to tweak piece values. You create one or more invisible squares outside the board, and fill them with empty pieces (either of a neutral party, or an equal amount of black and white dummy-pieces). Then you make an add to these squares, but first you must verify that it's empty:
(define tweak-shift ( $1 (verify empty?) add))
These extra adds must be placed outside the normal move type, so that they get a lower priority (to avoid that Zillions wastes time on them). The more adds you make to these external squares, the higher is the piece value. If you need to lower the piece value, you must increase the piece value in all the others. When increasing the general piece value of all pieces, the queen must have most adds, and the pawns need only a few, perhaps only one extra add. Have a look in any of my implementations:
http://hem.passagen.se/melki9/chessvar.htm
/Mats