Author: chandler yergin
Date: 02:15:43 04/12/05
Go up one level in this thread
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:
>>>>>
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bc3 Be3
>>>>> +- (9.95) Depth: 5/16 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5
>>>>> +- (9.95) Depth: 6/19 00:00:00
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5 5.Kg2
>>>>> +- (10.04) Depth: 7/18 00:00:00 59kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.b3 Nd5 5.Qg5 Re5
>>>>> +- (10.13) Depth: 8/20 00:00:00 130kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Nf6 Nd2 4.Rf5 Re2+ 5.Rf2 Nf1+ 6.Kg2 Rxf2+ 7.Kxf2 Ne3
>>>>> +- (10.20) Depth: 9/20 00:00:01 259kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.Nd6 Na4 5.Nxe8 Rxe8
>>>>> +- (10.45) Depth: 10/26 00:00:01 488kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rce8 3.Bxb6 Nxb6 4.Nd6 Re2+ 5.Kg1 Nd5 6.Nxe8 Rg2+ 7.Kxg2 Nf4+
>>>>>8.gxf4
>>>>> +- (10.95) Depth: 10/26 00:00:01 527kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Ra8 3.Qh4 Re6 4.Nc3 h6 5.Bxg7+ Kg8 6.Bxh6 Nxb2 7.Qg4+ Rg6
>>>>>8.Bxg6
>>>>> +- (15.46) Depth: 10/34 00:00:04 1467kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Bxb6 Nxb6 4.Nd6 h6 5.Qg6 Nc4 6.Nf7+ Rxf7 7.Qh7#
>>>>> +- (15.70) Depth: 11/32 00:00:07 2343kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3 4.Bxe3 Bc7 5.Nf7+ Rxf7 6.Rxf7
>>>>> +- (15.95) Depth: 12/41 00:00:14 4606kN
>>>>>1.Bf6 Rxe7 2.Bxd4 Rg8 3.Ng5 Ne3 4.Bxe3 Bc7 5.Nf7+ Rxf7 6.Rxf7 Be5
>>>>> +- (16.45) Depth: 12/41 00:00:14 4749kN
>>>>>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?
>Take, for example, the next-to-last PV from Shredder:
>
>1.Bf6 Rxe7 2.Bxd4 Rd8 3.Qh4 h5 4.Qxe7 Ne5 5.Qxe5 Bxd4 6.Qxh5+ Kg8 7.Bb3+ Rd5
>8.Bxd5#
>
>Even this is not correct, because if Black plays 2...Rd8, then White has a Mate
>in 5 (total of 7 moves from the initial position).
>
>Shredder is clearly wrong in its output, although I am impressed at the speed at
>which it found the best move.
>
>jm
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