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Subject: Re: SEE & accuracy

Author: Stuart Cracraft

Date: 14:37:15 08/21/04

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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.



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