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

Author: Robert Hyatt

Date: 07:47:13 05/02/04

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On May 01, 2004 at 19:33:02, J. Wesley Cleveland wrote:

>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.


You should be using 19.12 which doesn't do this as it fails high/low in
increments, not all at once.



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