Author: John Merlino
Date: 19:57:09 04/12/05
Go up one level in this thread
On April 12, 2005 at 22:33:07, chandler yergin wrote: >On April 12, 2005 at 21:56:10, John Merlino wrote: > >>On April 12, 2005 at 20:44:38, chandler yergin wrote: >> >>>On April 12, 2005 at 18:13:59, John Merlino wrote: >>> >>>>On April 12, 2005 at 15:20:35, chandler yergin wrote: >>>> >>>>>On April 12, 2005 at 11:54:35, John Merlino wrote: >>>>> >>>>>>On April 12, 2005 at 05:15:43, chandler yergin wrote: >>>>>> >>>>>>>On April 12, 2005 at 00:23:30, John Merlino wrote: >>>>>>> >>>>>>>>On April 11, 2005 at 23:36:27, chandler yergin wrote: >>>>>>>> >>>>>>>>>On April 11, 2005 at 13:00:10, Rob Basham wrote: >>>>>>>>> >>>>>>>>>>On April 11, 2005 at 12:24:18, John Merlino wrote: >>>>>>>> >>>>>>>>>>>>New game, >>>>>>>>>>>>[D]2r1r2k/4R1pp/pb6/1p6/2nqN1QB/P5PP/1PB4K/5R2 w - - 0 1 >>>>>>>>>>>> >>>>>>>>>>>>Analysis by Shredder 8: >>>>>> >>>>>><Some Analysis Snipped> >>>>>> >>>>>>>>>>>>1.Bf6 Qxf6 2.Nxf6 Bg1+ 3.Kxg1 Rg8 4.Nxg8 Nxb2 5.Qxg7# >>>>>>>>>>>> +- (#152) Depth: 12/42 00:00:22 7641kN >>>>>>>>>>>>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Ree8 4.Nc3 Re2+ 5.Nxe2 h6 6.Kh1 Rxd4 7.Rf8# >>>>>>>>>>>> +- (#152) Depth: 13/18 00:00:23 7840kN >>>>>>>>>>>>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Bxd4 4.Qxe7 Rg8 5.Rf8 Bg1+ 6.Kxg1 Nd6 7.Qxd6 b4 >>>>>>>>>>>>8.Rxg8+ Kxg8 9.Qd8+ Kf7 >>>>>>>>>>>> +- (#150) Depth: 14/40 00:00:43 15586kN >>>>>>>>>>>>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 Bxd4 4.Qxe7 Rg8 5.Rf8 Bc5 6.Nxc5 Nd6 7.Qxd6 b4 >>>>>>>>>>>>8.Rxg8+ Kxg8 9.Qe6+ Kf8 10.Nd7# >>>>>>>>>>>> +- (#150) Depth: 15/36 00:00:43 15751kN >>>>>>>>>>>>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 h5 4.Qxe7 Ne5 5.Qxe5 Bxd4 6.Qxh5+ Kg8 7.Bb3+ Rd5 >>>>>>>>>>>>8.Bxd5# >>>>>>>>>>>> +- (#150) Depth: 16/38 00:00:47 17089kN >>>>>>>>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Qf5 Kg8 4.Ng5 g6 5.Qd5+ Re6 6.Rf8+ Kxf8 7.Qf3+ Ke7 >>>>>>>>>>>>8.Qb7+ Bc7 9.Qxc7+ Kf8 10.Qg7# >>>>>>>>>>>> +- (#150) Depth: 17/36 00:00:49 17858kN >>>>>>>>>>>> >>>>>>>>>>>>(, 11.04.2005) >>>>>>>>>>> >>>>>>>>>>>Shredder's output is incredibly bizarre here. The position is a Mate in 9, but >>>>>>>>>>>not a single PV shows mate in 9 moves (although there are mates shown in 10, 7 >>>>>>>>>>>and even 5 moves!??). >>>>>>>>>>> >>>>>>>>>>>Conclusion: Shredder found the best move, but did NOT conclusively find the mate >>>>>>>>>>>in 9. >>>>>>>>> >>>>>>>>>THe Mate in 9 is not forced; Shredder gave all the variations leading to >>>>>>>>>Mate after the Key Move. >>>>>>>>> >>>>>>>>>With "Best PLay" by Black it's Mate in 9. >>>>>>>>> >>>>>>>>>If Black errs.. he gets Mated sooner. >>>>>>>> >>>>>>>>I understand that, but Shredder's output still makes no sense at all. What do >>>>>>>>you mean by "Shredder gave all the variations leading to Mate after the Key >>>>>>>>Move"? >>>>>>> A Program evaluates every possible move at each ply depth; >>>>>>>that is one complete iteration. >>>>>>>Shredder found a Mate at ply 12, another at ply 13, another at ply 14, >>>>>>>another at ply 15, another at play 16 etc. >>>>>>> >>>>>>>What don't you understand? >>>>>> >>>>>>Simple -- take this PV from Shredder (which is the first one listed above): >>>>>> >>>>>>1.Bf6 Qxf6 2.Nxf6 Bg1+ 3.Kxg1 Rg8 4.Nxg8 Nxb2 5.Qxg7# >>>>>> +- (#152) Depth: 12/42 00:00:22 7641kN >>>>>> >>>>>>A program should not announce a Mate for the side to move that is simply not >>>>>>possible with best play. If I were to stop analysis at this point and post my >>>>>>findings here, it would be soundly refuted by the simple fact that there is no >>>>>>Mate in 5 for White. >>>>>> >>>>>>It seems bizarre to me that, at depth 12, the Shredder thinks that there is a >>>>>>forced mate in 5 (only 9 plies away). >>>>>> >>>>>>jm >>>>> The Program did what a Program is supposed to do! >>>>> >>>>>I "clipped" the analysis. >>>>>Do you have any doubt, that if I had let it run,. that it would stabalize >>>>>on the Mate in 9 with a deeper search? >>>> >>>>No, I have no doubt about that at all. But there are two problems with that: >>>> >>>>1) Anybody could say that about any program with regards to a forced mate of >>>>reasonably short distance, and >>>> >>>>2) It's not the ability to find the mate that I have called into question. It is >>>>the PV output that makes no sense. (Notice that I haven't even mentioned the >>>>"#150" that Shredder regularly puts out for no reason....) >>>> >>>>jm >>> >>>That's because you don't have clue what the Program is doing! >> >>If you say so.... >> >>jm > >I apologize, I don't mean to be sarcastic.. >But if you have the Manual, please read it. Sorry, but I do not own Shredder. If you (or somebody else) could quote the proper section from the manual, I'm sure I would understand. jm
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