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Subject: Re: For the Record .. Deeper search & Eval Mate in 14

Author: Robert Hyatt

Date: 09:27:56 12/03/05

Go up one level in this thread

On December 03, 2005 at 11:12:23, chandler yergin wrote:

>New game
>[D]3Q4/bp3pp1/6k1/8/7R/6p1/B2p1PP1/q1rn2K1 w - - 0 1
>
>Analysis by Shredder 8:
>
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 10/10   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 12/12   00:00:00  26kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 13/13   00:00:00  41kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 14/14   00:00:00  75kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 15/15   00:00:00  153kN
>1.Qd3+ f5 2.Qxg3+
>  +-  (#14)   Depth: 16/16   00:00:00  247kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Qxd2
>  +-  (#11)   Depth: 17/18   00:00:01  596kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+
>  +-  (#14)   Depth: 18/54   00:07:23  166686kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 19/55   00:07:28  169067kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+
>  +-  (#14)   Depth: 20/53   00:07:35  171711kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 21/56   00:07:42  174826kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 22/36   00:07:49  178326kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 23/38   00:08:03  184315kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 24/40   00:08:26  194168kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 25/43   00:08:56  207920kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 26/43   00:09:43  229005kN
>1.Qd3+ f5 2.Qxg3+ Kf6 3.Qd6+ Kg5 4.Rh5+ Kxh5 5.Bf7+ Kg5 6.Qg3+ Kf6 7.Qg6+ Ke5
>8.Qe6+ Kf4 9.g3+ Kg4 10.Qg6+ Kf3 11.Qxf5+
>  +-  (#14)   Depth: 27/41   00:11:01  263041kN
>
>(, MyTown 03.12.2005)
> Which is what I said; deeper search confirms.
>I see no Bug, the Program found a Mate in 11 in .01 seconds
>I cut the analysis short. My error, not the Program.


You may not see the bug, or you may not understand the bug.  But it is
absolutely a bug.

Pick up _any_ AI textbook.  Alpha/Beta is _guaranteed_ to return the same score
as a pure minimax search, only far faster.  If a minimax search says "mate in
11", and there is no mate in 11 present, then that is a bug, nothing more,
nothing less.  Many programs will find a mate that is sub-optimal (longer) but
if one finds one that is shorter than can be forced, it is simply a bug.

It is time to move on...

• Re: For the Record .. Deeper search & Eval Mate in 14 Tony Werten 01:49:55 12/04/05
  • Re: For the Record .. Deeper search & Eval Mate in 14 Robert Hyatt 07:53:33 12/04/05
  • Re: For the Record .. Deeper search & Eval Mate in 14 Uri Blass 03:17:18 12/04/05
    • Re: For the Record .. Deeper search & Eval Mate in 14 Tony Werten 23:08:15 12/04/05

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