Author: Dann Corbit
Date: 15:30:42 05/02/05
Go up one level in this thread
On May 02, 2005 at 18:29:16, Uri Blass wrote: >On May 02, 2005 at 18:21:03, John Merlino wrote: > >>On May 02, 2005 at 15:44:39, Dann Corbit wrote: >> >>>On May 01, 2005 at 15:18:05, John Merlino wrote: >>> >>>>On May 01, 2005 at 12:35:59, chandler yergin wrote: >>>> >>>>>I think someone posted this position as 'the grind'? >>>>> >>>>>Shredder finds the Mate. >>>>> >>>>>[D]1rb3kr/p2q1ppp/1p1N4/3QPP2/8/8/P1P3PP/1R3R1K w >>>>> >>>>>.e6 Qc7 2.exf7+ Kf8 3.Rbe1 g6 4.fxg6 Be6 >>>>> +- (5.66) Depth: 7/21 00:00:45 54kN >>>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bb7 4.Re8+ Rxe8 5.fxe8Q# >>>>> +- (6.16) Depth: 7/21 00:00:47 62kN >>>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bd7 4.Qe5 Qd8 5.f6 g6 >>>>> +- (6.44) Depth: 7/29 00:00:49 77kN >>>>>1.e6 Qc7 2.exf7+ Kf8 3.Rbe1 Bd7 4.Qe5 Qd8 5.f6 Qe7 6.Qxe7# >>>>> +- (6.69) Depth: 8/22 00:00:55 100kN >>>> >>>>See this thread: >>>> >>>>http://www.talkchess.com/forums/1/message.html?423252 >>>> >>>>As you can see, it is a mate in approximately 15 moves, and you are yet another >>>>victim of Shredder's deceptive (or, as I like to put it, "totally wrong") PVs >>>>and/or evals. >>> >>>Many programs will cough up a pound sign in the principal variation and yet >not show a mate score. >>> >>>The depth of search above is 8 plies, and so these moves: >>>... 5.f6 Qe7 6.Qxe7# >>>are obviously speculative. >> >>Ok, I'll believe you, but I still don't get WHY. A program should not show a >>mating line in a PV if the mate is not forced, IMHO. > >I guess that the reason is that Shredder's evaluation does not see the mate. > >My guess is that Shredder's engine does not know that the pv ends in mate and >the interface calculates and find that the pv end with mate score. > >Note that I think that engines should see mate by evaluation function and Movei >does it but there are a lot of engines that do not do it. Probably, Shredder is picking up pv moves from the hash table, which means that anything is possible.
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