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Subject: Re: Chess program improvement project (copy at Winboard::Programming)

Author: Robert Hyatt

Date: 12:42:29 03/07/06

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A note.  This is not a good way to test programs that use something like the
late-move reductions.  The trees may well be searched in a different order when
you flip or flop the board from side to side, since for a bitboard program,
FirstOne() will find a different bit set, which means moves for pieces will
likely pop out in a different order.  And that affects the history values enough
that you could end up pruning in one position but not in another, depending on
how late or early a key move is searched.

This is a good approach for pure static evaluation testing, but once you get
into the dynamics of the search tree, particularly with forward pruning (or
reductions, however you think about it) you can't search the same tree easily
since the pieces are on different squares, and so the final result can vary.
Trying to debug that is basically chasing your tail...



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