Author: Heiner Marxen
Date: 10:55:00 05/05/02
Go up one level in this thread
On April 28, 2002 at 22:00:22, Heiner Marxen wrote: >On April 28, 2002 at 18:18:38, Heiner Marxen wrote: > >>On April 28, 2002 at 08:00:15, Vincent Vega wrote: >> >>>Simplified position to show the bug: >>>[D]8/8/8/8/8/8/4KP2/R1Qn3k w - - 0 1 >>> >>>This is a mate in 2 (1. Qxd1+). >>> >>>But CHEST says: >>> >>>CHEST version 3.19, 18-Dec-1999 >>>Input file: 'xx' >>>Reading job: >>># xx >>>W: Ke2 Qc1 Ra1 Pf2 (4) >>>B: Kh1 Nd1 (2) >>>FEN: 8/8/8/8/8/8/4KP2/R1Qn3k w - - >>>analysing (mate in 2 moves): >>>No solution in 2 moves. >>>refu 1: Qxd1+ -- [ 1-] M2: move >>>refu 2: Qc6+ -- [ 1-] M2: move >>>refu 3: Qh6+ Kg1 [ 1-] >>>refu 4: f3 -- [ 1-] M2: move >>>refu 5: f4 -- [ 1-] M2: move >>>refu 6: Rb1 -- [ 1-] M2: move >>>refu 7: Ra2 -- [ 1-] M2: move >>>refu 8: Ra3 -- [ 1-] M2: move >>>refu 9: Ra4 -- [ 1-] M2: move >>>refu 10: Ra5 -- [ 1-] M2: move >>>refu 11: Ra6 -- [ 1-] M2: move >>>refu 12: Ra7 -- [ 1-] M2: move >>>refu 13: Ra8 -- [ 1-] M2: move >>>refu 14: Qb1 -- [ 1-] M2: move >>>refu 15: Qc2 -- [ 1-] M2: move >>>refu 16: Qc3 -- [ 1-] M2: move >>>refu 17: Qc4 -- [ 1-] M2: move >>>refu 18: Qc5 -- [ 1-] M2: move >>>refu 19: Qc7 Kg1 [ 1-] >>>refu 20: Qc8 -- [ 1-] M2: move >>>refu 21: Qd2 -- [ 1-] M2: move >>>refu 22: Qe3 -- [ 1-] M2: move >>>refu 23: Qf4 Kg1 [ 1-] >>>refu 24: Qg5 -- [ 1-] M2: move >>>refu 25: Qb2 -- [ 1-] M2: move >>>refu 26: Qa3 -- [ 1-] M2: move >>>refu 27: Kd2 -- [ 1-] M2: move >>>refu 28: Ke1 -- [ 1-] M2: move >>>refu 29: Kf3 -- [ 1-] M2: move >>>refu 30: Kxd1 -- [ 1-] M2: move >>>refu 31: Kf1 Ne3+ [ 1-] >>>refu 32: Kd3 -- [ 1-] M2: move >>>Time (virt) = 0.000 sec >> >>Sadly, I have to confirm this fact: this is a bug in Chest. >>If I specify option "-2" to suppress the "2-mate-heuristic", it finds the >>mate in 2: >> >> Qxd1+ Kh2 Qh1# >> Kg2 Qh1# >> >>Hence, the bug is in the "mate2" module. Since that one is a really complex >>one, it will take some time to track it down. >>When I have found it, I will report under what circumstances it does appear. > >Fortunately, I could track down this bug. [snip] >It is quite easy to correct this bug, and within the next week I will >provide a corrected source module. >It will be announced here, and be available through my web page. http://www.drb.insel.de/~heiner/Chess/chest.html contains a reference to the corrected source code "mate2.c": http://www.drb.insel.de/~heiner/Chess/mate2.c >Hopefully Dann will then provide a corrected win32 executable. >Since the circumstances for the bug to occur are not really very rare, >I'd recommend upgrading to the new version when available. I can't speak for Dann, but it would be very nice of him to offer an updated source package, and more importantly, a corrected binary. (I myself cannot compile for windows). >Thanks, Vincent, for providing a simplified bug report, that helped a lot! Thanks again! Happy problem solving for all! Heiner
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