Author: Stuart Cracraft
Date: 19:08:07 08/22/04
Go up one level in this thread
On August 21, 2004 at 13:36:50, Michael Henderson 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 cuts losing captures and WAC may involve "losing captures" (scored by SEE) >as the winning moves. Try running the test at more than 1 sec/move. The extra >speed and depth you gain from SEE (cut qsearch) will probably equal or outweigh >the "losing" but winning captures pruned from SEE. Be aware that SEE is very >safe and effective to use in quiet positions but not so much in tactical >positions (unless you let it run longer). > >Michael More time always helps. :-) Bob has pointed out my SEE (actually another SEE just donated for the minimax/exchange code into my program) lacks X-ray attackers and this is significant. Perhaps when they're added in, something good will happen. I've been tied up with other things so far today but it's high on the list. Stuart
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