Author: Robert Hyatt
Date: 14:09:57 03/31/00
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On March 31, 2000 at 00:52:55, Ed Schröder wrote: >On March 31, 2000 at 00:25:23, James Robertson wrote: > >>On March 30, 2000 at 18:32:40, Robert Hyatt wrote: >> >>>On March 30, 2000 at 15:04:09, Inmann Werner wrote: >>> >>>>On March 30, 2000 at 11:07:16, Robert Hyatt wrote: >>>> >>>> >>>>>Here is mine: >>>>> >>>>>1. hash table move. >>>>>2. captures that don't appear to lose material using a SEE procdedure, >>>>>ordered from biggest gain to equal exchanges. >>>>>3. 2 killer moves. >>>>>4. up to 4 history ordered moves (history heuristic) >>>>>5. rest of the moves. >>>> >>>>question to 5) >>>>here is the rest of the non capturing moves and the "loosing capture" moves. >>>>Which of them should be searched first? >>>> >>>>IMHO the non capturing moves. >>>> >>>>Werner >>> >>> >>>In my case, losing captures come first, but only because that is the way they >>>appear in the list. IE I generate captures, sift the good ones to the top, and >>>leave the lemons at the bottom. Later I generate the rest of the moves and add >>>to the list, which places them after the lemons... >> >>Have you tested to see if the move ordering could be improved? In my case I >>search: > >>Hash move >>Winning captures > >Third in Rebel is Queen promotions. > >>Equal captures > >Remaining promotions. > >Ed > >>2 Killer Moves >>Noncaptures ordered by the history table >>All captures (even the ones we already searched) ordered by the history table >> >>James I factor all of this into captures. IE in Crafty, a capture is a capture _or_ a pawn promotion. The SEE routine treats a8=Q as though it wins 8 points (queen-pawn). If the new queen is simply hanging, the SEE routine will adjust the score down by 9, to -1 (the pawn is simply lost). This means that I will search a8=Q before I search NxR, assuming the new queen can't be captured and the rook isn't either... I wasn't clear when I said "non-losing captures." It should have said " captures/promotions that appear to not lose material" Bob
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