Author: Robert Hyatt
Date: 07:53:33 12/04/05
Go up one level in this thread
On December 04, 2005 at 04:49:55, Tony Werten wrote: >On December 03, 2005 at 12:27:56, Robert Hyatt wrote: > >>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. > >Why would checkmate scores have to be exact ? > >You can choose to return (heuristic)checkmate scores from eval, with some bound >on iteration depth. > > >Tony Sure you can, but are you going to return "mate in 100+" or "mate in 11". I predict mate in 11 will totally wreck the search. Generally a mate in 11 is actually _found_ in the search, and a shorter mate than is actually possible is just a bug that needs to be found. > >> >>It is time to move on...
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