Author: Mikael Bäckman
Date: 00:42:22 03/03/06
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On March 02, 2006 at 14:50:55, Robert Hyatt wrote: >On March 02, 2006 at 13:08:00, Alessandro Scotti wrote: > >>On March 02, 2006 at 11:45:14, Robert Hyatt wrote: >> >>>notice the index calculation above... from * 64 + to, which certainly gives a >>>12 bit index into a 12 * 64 table. That has to be a bug, or else I am missing >>>something. Note that someone just sent me the pieces above, not the entire >>>fruit source so I have not looked at the surrounding code to see if there is >>>more to the story... >> >>I haven't checked Fruit code on that, but I use two separate tables in Kiwi, a >>2*64*64 table (side/from/to) for move ordering, and a 12*64 (piece/to) table for >>reductions. > > >OK. what is the justification? Have you compared them? (I have not tried the >piece/to approach so have no data). Real question has to be is piece-to better >than from-to in any sense other than being a bit more cache-friendly??? I use Piece-To indexing in Chepla. Re-ran some tests yesterday, and my results are in favor of Piece-To compared to From-To. Tested 50 middlegame positions 5 times, increasing the search depth each time. The tree size was increasingly smaller for the Piece-To approach. The results were about (if memory serves me right...): Depth Tree reduction ---------------------- 7 <1% 8 1% 9 2% 10 3% 11 5% /Mikael
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