Author: Omid David Tabibi
Date: 01:52:53 06/15/04
Go up one level in this thread
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. > >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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