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Subject: Re: SEE & accuracy

Author: Robert Hyatt

Date: 14:23:30 08/21/04

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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...



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