Author: Mike S.
Date: 12:29:51 01/08/04
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On January 08, 2004 at 14:17:52, Drexel,Michael wrote: >I can reproduce it with Cb-native Crafty 19.06 and Crafty 19.08. > >Crafty 19.06 - Hiarcs 9 >8/6r1/8/5p1B/5N2/4k1K1/8/8 w - - 0 1 > >Analysis by Crafty 19.06 CB: > >1. = (-0.01): 137.Bg6 Rxg6+ >2. = (-0.01): 137.Ng6 f4+ 138.Kh4 Rh7 139.Ne5 Rxh5+ >3. -+ (-#15): 137.Kh3 Kxf4 >4. -+ (-#15): 137.Kh2 Kxf4 I cannot reproduce Bg6?? with cb-native Crafty 19.06 on a Pentium 3/700 MHz, using 4-piece tbs. (+ all rook vs. rook-tbs which don't matter here): Crafty 19.06 - Hiarcs 9 8/6r1/8/5p1B/5N2/4k1K1/8/8 w - - 0 1 Analysis by Crafty 19.06: 1. = (-0.01): 137.Ng6 f4+ 2. -+ (-6.02): 137.Bg6 Ke4 138.Ne2 Rxg6+ 139.Kf2 Rc6 140.Ng3+ Ke5 141.Nf1 Rc1 142.Ng3 Rc2+ 143.Kg1 f4 3. -+ (-12.05): 137.Kh3 Kxf4 138.Be2 Rh7+ 139.Kg2 Ke3 140.Ba6 f4 141.Bb5 f3+ 142.Kg3 Rg7+ 143.Kh4 Kf4 4. -+ (-#17): 137.Kh2 Kxf4 138.Bd1 Ke3 139.Kh3 f4 or single pv: Analysis by Crafty 19.06: 137.Ng6 f4+ 138.Kh4 f3 139.Bxf3 Rxg6 = (-0.01) Depth: 15/15 00:00:00 = (-0.01) Depth: 19/30 00:00:23 12179kN, tb=32966 Maybe it's not a bug, but one of these (seemingly inavoidable) nullmove effects when zugzwang is involved. It seems to me, Bg6?? can be produced when the engine - obviously - misses the reply Ke4, which puts Black in zugzwang. Nimzo 8 seems also to be affected by this nullmove problem in this position: Crafty 19.06 - Hiarcs 9 8/6r1/8/5p1B/5N2/4k1K1/8/8 w - - 0 1 Analysis by Nimzo 8: 137.Bg4 -+ (-8.92) Depth: 1/11 00:00:00 137.Ng6 f4+ 138.Kh4 Rh7 139.Ne5 Ke4 140.Nc4 Rxh5+ 141.Kxh5 f3 = (-0.19) Depth: 1/11 00:00:00 ³ (-0.60) Depth: 8/22 00:00:00 137.Bg6 Rxg6+ 138.Nxg6 = (-0.08) Depth: 8/22 00:00:00 = (0.00) Depth: 23/44 00:00:57 32546kN, tb=1791 The problem seems to disappear immediatly when I switch to multi-pv mode: Analysis by Nimzo 8: 1. = (-0.05): 137.Ng6 f4+ 138.Kh4 Rc7 139.Bg4 Rc5 140.Be2 Rc1 141.Bg4 Rg1 142.Ne5 2. -+ (-4.76): 137.Bg6 Ke4 138.Kf2 Kxf4 139.Be8 Ra7 140.Bc6 Ra2+ 141.Kf1 Ke3 142.Bd5 Regards, M.Scheidl
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