Author: Tony Werten
Date: 13:44:47 06/15/04
Go up one level in this thread
On June 15, 2004 at 11:41:30, Omid David Tabibi wrote: >On June 15, 2004 at 07:48:48, Tony Werten wrote: > >>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. >> >>Did you split black and white zugzwangs now ? > >I'm not quite sure what you mean, but the algorithm works the same for both >white and black :) In your original paper, you said that after a fail high, you reduce depth, and during this reduced search, you accepted new fail high on nullmoves as ok. IMO this was wrong because you could be doing a verification search for white, but accepting a nullmove fail high for black. Tony > > >> >>Tony >> >>> >>> >>>> >>>>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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