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Subject: Re: Two Test Positions = Queen and Pawn Endings

Author: J. Wesley Cleveland

Date: 16:33:02 05/01/04

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On May 01, 2004 at 17:33:34, Vincent Lejeune wrote:

>On May 01, 2004 at 17:05:27, J. Wesley Cleveland wrote:
>
>>On April 30, 2004 at 23:43:48, Robert Hyatt wrote:
>>
>>>On April 30, 2004 at 17:21:34, José Antônio Fabiano Mendes wrote:
>>>
>>>> [D]7k/6p1/2P3Qp/p3q2P/8/6P1/5K2/8 w
>>>> Bogoljubow vs Stahlberg, Kemeri 1933  1. Qc2!! Qxh5 2. Qc4!
>>>
>>>This one takes crafty depth=16, not real quick.  Almost 4 minutes to pick Qc2,
>>>several more to see how good it really is...
>>>
>>[snip]
>>While looking at this with crafty, I found the ugliest fail high I've seen with
>>crafty.
>>
>>[D]2q4k/6p1/2P4p/p7/2Q5/6P1/6K1/8 w - - 0 4
>>
>>hash table memory =   96M bytes.
>>pawn hash table memory =    6M bytes.
>>
>>Crafty v19.10
>>
>>White(1): sd 11
>>search depth set to 11.
>>White(1): 2q4k/6p1/2P4p/p7/2Q5/6P1/6K1/8 w - - 0 4
>>White(1): analyze
>>Analyze Mode: type "exit" to terminate.
>>end-game phase
>>              clearing hash tables
>>              time surplus   0.00  time limit 22.50 (3:30)
>>              depth   time  score   variation (1)
>>                7->   0.12  -0.14   1. Qb5 Qd8 2. Kf3 Qf8+ 3. Kg4 Qd6 4.
>>                                    Kf5 Qc7
>>                8     0.18  -0.15   1. Qb5 Qd8 2. Kf3 Qd6 3. Qc4 Qf6+ 4.
>>                                    Kg4 g6 5. Qd5
>>                8     0.46  -0.03   1. Kf3 Qd8 2. Qe4 Qd1+ 3. Kf4 Qd6+
>>                                    4. Kf3 Qc7 5. Qd5 <HT>
>>                8->   0.48  -0.03   1. Kf3 Qd8 2. Qe4 Qd1+ 3. Kf4 Qd6+
>>                                    4. Kf3 Qc7 5. Qd5 <HT>
>>                9     0.95  -0.05   1. Kf3 Qf5+ 2. Ke3 Qe5+ 3. Kf3 Qf6+
>>                                    4. Ke4 Qe7+ 5. Kf3 Qa3+ 6. Kg2 Qf8
>>                                    7. c7 Qa8+ 8. Kf2 Qc8
>>                9     1.14   0.01   1. Qd5 a4 2. Qd7 Qa6 3. c7 Qe2+ 4.
>>                                    Kh3 Qh5+ 5. Kg2 Qe2+
>>                9->   1.15   0.01   1. Qd5 a4 2. Qd7 Qa6 3. c7 Qe2+ 4.
>>                                    Kh3 Qh5+ 5. Kg2 Qe2+
>>               10     1.28   0.01   1. Qd5 a4 2. Qd7 Qa6 3. c7 Qe2+ 4.
>>                                    Kh3 Qh5+ 5. Kg2 Qe2+
>>               10     1.87     ++   1. c7!!
>>               10    17:13   1.45   1. c7 Qb7+ 2. Kh2 Qc8 3. Qc5 Kh7 4.
>>                                    g4 Kh8 5. Qxa5 <HT>
>>               10->  17:13   1.45   1. c7 Qb7+ 2. Kh2 Qc8 3. Qc5 Kh7 4.
>>                                    g4 Kh8 5. Qxa5 <HT>
>>               11    17:14     ++   1. c7!!
>>               11    17:15   5.72   1. c7 Qb7+ 2. Kh2 Qc8 3. Qc5 Kh7 4.
>>                                    g4 a4 5. Qf5+ Qxf5 6. gxf5 a3 7. c8=Q
>>                                    a2 8. Qc3
>>               11->  17:15   5.72   1. c7 Qb7+ 2. Kh2 Qc8 3. Qc5 Kh7 4.
>>                                    g4 a4 5. Qf5+ Qxf5 6. gxf5 a3 7. c8=Q
>>                                    a2 8. Qc3
>>              time=17:15  cpu=88%  mat=-1  n=1791242494  fh=99%  nps=1.73M
>>              ext-> chk=381633369 cap=48652 pp=55417 1rep=27688883 mate=994
>>              predicted=0  nodes=1791242494  evals=48417627
>>              endgame tablebase-> probes=0  hits=0
>>              hashing-> 65%(raw) 64%(depth)  99%(sat)  99%(pawn)
>>              hashing-> 0%(exact)  56%(lower)  1%(upper)
>
>
>Shredder think it's a draw after 1.c7, some pertpetual missed to crafty I think.
>Could you let crafty think a little longer ? I'm about sure you will see the
>"ugliest fail low you've seen with crafty" ;)
>
Crafty fails low to a draw score quickly on the next ply. What makes this so
ugly is that it takes 1.87 seconds to fail high, and 17:13 *minutes* to resolve
the fail high.



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