Author: Uri Blass
Date: 08:02:37 03/16/03
Go up one level in this thread
On March 16, 2003 at 10:32:38, Albert Bertilsson wrote: >WAC018 >[D]R7/P4k2/8/8/8/8/r7/6K1 w - - 0 1 >Bm: Rh8 > >no 1 0 +112 17 g1f1 >no 2 0 +100 46 g1f1 f7e6 >no 3 0 +112 277 g1f1 f7e6 a8d8 >no 4 0 +102 1215 g1f1 f7e6 a7a8Q a2a7 >no 5 10 +110 3437 g1f1 a2a4 a8a7 a4a7 a7a8Q >no 6 30 +102 10970 g1f1 a2a4 a8d8 a4a1 a7a8Q a1a7 >no 7 130 +110 47784 g1f1 f7e7 a8d8 a2a1 a7a8Q a1a7 a8d5 >no 8 360 +102 118351 g1f1 f7e7 a8d8 a2a1 a7a8Q a1a2 a7a8Q a2a7 >no 9 1230 +97 503068 g1h1 f7e7 a8d8 g7g8 a7a8Q b7a7 a8d5 a7a8 > d5b7 >no 10 4460 +102 1482941 g1h1 a2a1 a7a8Q a1a2 a7a8Q a2a1 a7a8Q > a1a2 a8a1 a2a7 >no ??? 4980 (moved) ??? g1h1 First bug Your pv include illegal move After Kh1 Ra1+ the move a7a8Q is illegal for the following 2 reasons: 1)The king is in check 2)There is a rook in a8 so it is impossible for a pawn to promote to that square. This is not the only case when your pv include illegal moves. Note that check extensions may help in this position. > > > > >WAC035 >[D]r3r2k/2R3pp/pp1q1p2/8/3P3R/7P/PP3PP1/3Q2K1 w - - 0 1 >Bm: Rxh7+ > >no 1 0 +131 56 c7c1 >no 2 0 +118 305 d1c2 d6c7 >no 3 0 +121 2115 c7c1 d6c7 d4e5 >no 4 50 +111 19818 c7c1 d6c7 c7c6 e8e4 >no 5 120 +116 63248 c7c1 d6c7 d4e5 e8e4 g4g7 >no 6 890 +125 346250 d1b1 d6c7 d4e5 e8e4 c7c6 a8d8 >no 7 1850 +123 1286098 d1b1 d6c7 d4e5 e8e4 c1c7 a8d8 f2g3 >no ??? 4970 (moved) ??? d1b1 This is mate in 4 when all the moves are checks. Even with no extensions you should find it at depth 7 if you use legal move generator. Maybe your problem is bad order of moves and lack of pruning because I see a bad branching factor. > > > > >WAC041 >[D]1k6/5RP1/1P6/1K6/6r1/8/8/8 w - - 0 1 >Bm: Ka5 Kc5 b7 > >yes 1 0 +301 27 b6b7 >yes 2 0 +296 62 b6b7 g4g8 >no 3 0 +652 1007 f7f8 g4g8 g7g8Q >no 4 10 +652 1464 f7f8 g4g8 f7f4 g8e8 >no 5 10 +652 9049 f7f8 g4g8 g7g8Q g8e8 b5b4 >yes 6 110 +305 22968 b6b7 g4g8 f4g4 g8e8 g7g8Q b8c8 >no 7 250 +652 115670 b5a6 g4g8 f7f8 g8e8 f8e8 b8c8 g7g8Q >no 8 780 +652 181629 b5a6 g4g8 f7f8 g8e8 f8e8 b8c8 a4a5 c8d7 >no 9 2160 +652 1433806 b5a6 g4g8 a5a4 g8e8 g7g8Q b8c8 a4a5 c8d7 > b7b8Q >no ??? 4970 (moved) ??? b5a6 > >Almost got it! But then it slipps away =(. When you have illegal moves in the pv then you clearly have a problem the pv at depth 3 is already illegal. > > > > >WAC046 >[D]r1bqr1k1/pp1nb1p1/4p2p/3p1p2/3P4/P1N1PNP1/1PQ2PP1/3RKB1R w K - 0 1 >Bm: Nb5 > >no 1 0 -3 64 h1h5 >no 2 0 -13 1379 h1h5 a8b8 >no 3 10 -4 5233 f1d3 a8b8 h1h5 >no 4 140 -9 45741 f1d3 a8b8 b5c7 g8f8 >no 5 350 -4 168925 f1d3 a8b8 h1h5 g8f8 d4e5 >no ??? 4970 (moved) ??? f1d3 very bad branching factor(more than 10 at depth 6). > > > > >WAC047 Should be WAC49 >[D]2b3k1/4rrpp/p2p4/2pP2RQ/1pP1Pp1N/1P3P1P/1q6/6RK w - - 0 1 >Bm: Qxh7+ > >no 1 0 -220 823 h4f5 >no 2 0 -220 1246 h4f5 d6e5 >no 3 0 -220 2699 h4f5 d6e5 g1e1 >no 4 10 -220 6282 h4f5 d6e5 g1e1 b2a1 >no 5 50 -215 25606 h4f5 d6e5 g1e1 b2a1 h5f7 >no 6 440 -143 204634 h5h6 d6e5 h4g6 b2a1 g1g2 a1d4 >no 7 1460 -152 655764 h5h6 d6e5 g1g7 b2a1 h1g2 a1d4 c1c4 >no ??? 4970 (moved) ??? h5h6 again lack of check extension is a problem. > > >How do I iron these out? Writing legal move gen is quite easy, since it can be >debugged in a methodic way, how do I debug a search? based on your pv you need to debug your legal move generator(or maybe the bug is in generating the pv array) Uri
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