Author: Vincent Diepeveen
Date: 10:18:54 06/15/04
Go up one level in this thread
On June 15, 2004 at 04:52:53, Omid David Tabibi wrote: >On June 14, 2004 at 21:45:44, Anthony Cozzie wrote: > >>On June 14, 2004 at 20:12:09, Omid David Tabibi wrote: >> >>>On June 14, 2004 at 19:20:57, Anthony Cozzie wrote: >>> >>>>On June 14, 2004 at 16:31:17, Jaime Benito de Valle Ruiz wrote: >>>> >>>>>[d]8/8/1p4p1/p5kp/Pp1QP1Pq/1P6/6K1/8 w - - 0 62 >>>>> >>>>>White moves and wins! >>>>>Can your engine find the right answer and give the proper "crushing" score >>>>>(around 9 pawns!) along with a proper PV? How long does it take? >>>>>Mine doesn't find anything after a long long time (over an hour), but with >>>>>null-move disabled, it takes only a few seconds to show the full PV. >>>>>(Some engines find the right answer, but with a small score, an absurd PV, and >>>>>they change their mind some plies later) >>>>> >>>>>In this position the black king is in a very delicate position: After a couple >>>>>of moves, if the black queen moves, white checkmates inmediately, so both kings >>>>>and queens must remain still while pawns play on their own. >>>>> >>>>>Any good suggestion to avoid this problem with null-move? >>>>> >>>>>Regards, >>>>> >>>>> Jaime >>>> >>>>Zappa doesn't get it either (gxh5 @ 15 ply after 1 minute). Zappa relies on >>>>double nullmove for zugzwang avoidance. This works find for positions with 1 >>>>zugzwang, but in this position black gets hit with about 10 of them :) >>> >>>Ehem, ehem, heard about verified null-move pruning? :) >>> >>> >>>> >>>>anthony >> >> >>It's a possibility. If I understand it correctly verifications performed >>nonrecursively. > >The original formulation had problems with detecting several zugzwangs in a >line, and I think it might have failed to find the correct move here. One of the >things I changed in the new formulation is to make the algorithm find as many >zugzwangs there might be along a line. In this position you only have to find 1 zugzwang, that's all. Evaluation doing the rest of the job then. > >> >>Right now, my goals are "Deep Zappa" aka "ParZappa" aka "Zappa-NUMA" aka "Zappa" >>and the autotuning stuff; when I get some free time I'll try to give it a shot. >> >>Oh, and I have to rewrite my eval again. >> >>anthony
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