Author: Robert Hyatt
Date: 14:52:58 08/21/04
Go up one level in this thread
On August 21, 2004 at 17:37:15, Stuart Cracraft wrote: >On August 21, 2004 at 17:23:30, Robert Hyatt wrote: > >>On August 21, 2004 at 13:20:11, Stuart Cracraft wrote: >> >>>All, >>> >>>SEE increases my nominal iteration depth by 0.42 pawns >>>given the same amount of time as a non-SEE search, all else >>> >>>SEE decreases my max quiescence depth reached (with a check handoff >>>to main search) by a little under 8 ply for the same problem set. >>> >>>These are the 300 positions from Win-at-Chess run at 1 second per >>>problem on an old, slow, notebook. I do not have comparative data >>>due to the subjectivity involved of chess games and the "feel of SEE". >>> >>>Legend: >>>Ave Iterative Depth/Average Max Search depth >>>% solved >>>Total solved / Total in test >>>Total time taken (300 seconds allowed) >>>Total Nodes searched >>>Average positions searched per problem / >>>Average time (rounded) per problem / >>>Average nodes per second per problem >>>0/0/Check Extensions from Quiescence back to Main Search/0/0 >>> >>>Without SEE >>> >>>**** 6.68/27.18 68% 204/300 269.05 54264704 180882/1/201692 0/0/3361112/0/0/0 >>> >>>With SEE >>> >>>**** 7.10/19.01 64% 193/300 267.44 46135172 153784/1/172505 0/0/1154026/0/0/0 >>> >>>Total problem solution rate drops 5.4% and nodes searched drops 14.98% >>> >>>(The SEE being used above was tried as (1) see < 0 then don't search >>>a capture move in quiescence and (2) see < delta where delta is calculated >>>with its margin off alpha as the maximum positional score so far in the >>>search for the side on move. The above results are the combination of both and >>>if only using the #2, assuming for example my SEE is not a great SEE, >>>the result is only slightly changed.) >>> >>>My question is, why should SEE reduce the tactical result so drastically >>>and is it safe to do so given the depth and nodes results are favorable? >>> >>>Thanks ahead, >>> >>>Stuart >> >> >>SEE should _help_ in tactics, not hurt. If it is hurting, there is something >>wrong somewhere... > >That's puzzling. I've tested it pretty thoroughly, manually, in a variety >of positions and think it is working right. It knows nothing of any secondary >effects, just the exchanging pieces. No x-rays, etc. > >Now I'm really nervous. No x-rays is a serious shortcoming. IE two rooks attacking the same square in battery. If you don't include the second rook I could see how SEE could cause problems. I handle X-rays pretty easily and always did even back in CB days...
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