Author: Heiner Marxen
Date: 15:18:38 04/28/02
Go up one level in this thread
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.
Sorry, but sooner or later some bug had to come up... Chest is just too
complex to be completely bug free.
Cheers,
Heiner
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