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Subject: Re: Testposition - Avoid Stalemate

Author: Robert Hyatt

Date: 19:03:01 03/18/01

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On March 18, 2001 at 11:38:31, Sune Larsson wrote:

>On March 18, 2001 at 10:16:04, Robert Hyatt wrote:
>
>>On March 18, 2001 at 07:34:42, Sune Larsson wrote:
>>
>>>On March 17, 2001 at 21:08:37, Robert Hyatt wrote:
>>>
>>>>On March 17, 2001 at 12:21:45, Sune Larsson wrote:
>>>>
>>>>>
>>>>>  8/2R5/k7/P7/2PK4/8/1P2r3/8 w - - 0 1
>>>>>
>>>>>
>>>>>  This position was sent to me just two hours ago (thanks!)
>>>>>  White has a won position but must avoid the last trap,
>>>>>  which is 1.b4?? and a draw. The programs I have tried
>>>>>  sees this but in different speed. (PIII 800)
>>>>>
>>>>>  Deep Fritz     0 sec
>>>>>  Nimzo 8        2  "
>>>>>  Hiarcs 7.32    2  "
>>>>>  Crafty 18.03  20  "
>>>>>  Fritz 5.32    48  "
>>>>>
>>>>>
>>>>>  Test: 1) Does your program realize that 1.b4?? is a draw?
>>>>>        2) How much time needed?
>>>>>
>>>>>  Sune
>>>>
>>>>
>>>>I am trying to understand your question.
>>>>
>>>>On my PIII/750 notebook, crafty changes from b4 to Kc3 after
>>>>4 seconds... and never considers b4 again...
>>>>
>>>>If I play b4 myself, it takes .8 seconds to get a score
>>>>of 0.00...
>>>>
>>>>Not sure why yours took 20 seconds to see that...
>>>
>>>
>>> Here is the output from Crafty 18.03, CB native, PIII 800, 128 MB Hash.
>>> Infinite analyse mode:
>>>
>>>
>>>Ny ställning
>>>8/2R5/k7/P7/2PK4/8/1P2r3/8 w - - 0 1
>>>
>>>Analysis by Crafty 18.03:
>>>
>>>1.b4
>>>  +-  (4.88)   Djup: 1/2   00:00:01
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6
>>>  +-  (4.78)   Djup: 5/9   00:00:01
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6
>>>  +-  (4.78)   Djup: 5/9   00:00:01
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6
>>>  +-  (4.78)   Djup: 5/9   00:00:01
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6
>>>  +-  (4.78)   Djup: 5/9   00:00:01
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6
>>>  +-  (4.58)   Djup: 6/13   00:00:01  8kN, tb=18
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Td6+
>>>  +-  (4.58)   Djup: 7/14   00:00:01  15kN, tb=21
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kd7 Td4+ 7.Ke7 Td1
>>>  +-  (4.48)   Djup: 8/16   00:00:01  31kN, tb=41
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kd7 Td4+ 7.Ke8 Te4+
>>>8.Kd8
>>>  +-  (4.38)   Djup: 9/17   00:00:01  66kN, tb=129
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kf6 Te6+ 7.Kg5 Te5+
>>>8.Kf4 Te4+ 9.Kf5 Td4
>>>  +-  (4.38)   Djup: 10/19   00:00:02  137kN, tb=270
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kf6 Tf4+ 7.Kg6 Tf6+
>>>8.Kh5 Tf5+ 9.Kh6 Tf6+ 10.Kg5 Te6
>>>  +-  (4.18)   Djup: 11/21   00:00:03  347kN, tb=693
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kf6 Tf4+ 7.Kg6 Tg4+
>>>8.Kh6 Tg6+ 9.Kh5 Tg5+ 10.Kh4 Tg4+ 11.Kh3 Tf4
>>>  +-  (4.00)   Djup: 12/25   00:00:05  765kN, tb=1686
>>>1.b4 Te4+ 2.Kd5 Td4+ 3.Ke5 Te4+ 4.Kd6 Td4+ 5.Ke6 Te4+ 6.Kf6 Tf4+ 7.Kg6 Tg4+
>>>8.Kh6 Tg6+ 9.Kh5 Tg5+ 10.Kh4 Tg4+ 11.Kh3 Tg3+ 12.Kh2 Tf3
>>>  +-  (4.00)   Djup: 13/25   00:00:12  2668kN, tb=5042
>>>1.b4 Te4+ 2.Kc5 Txc4+ 3.Kd6 Txb4
>>>  =  (0.01)   Djup: 14/29   00:00:26  6649kN, tb=13601
>>>1.Kc3
>>>  ²  (0.41)   Djup: 14/29   00:00:28  7605kN, tb=14685
>>>
>>>(Larsson, KIL 18.03.2001)
>>
>>
>>Something is odd there.    ie above, 3 seconds, 347K nodes.  That doesn't
>>look like a PIII/800 speed.  My PIII/750 searches at about 500K nodes per
>>second, rather than your 115K.
>>
>>Is something else running at the same time?
>
> Hm... you're absolutely right, something was wrong here. I remember that
> I made a fresh reboot, then checked the taskinfo, which showed about 99% idle,
> then loaded Crafty with 128 MB hash. Hm... maybe that was too much at that
> particular moment. Nothing else was running at the same time. Maybe memory
> swapping, though I have 256 MB. Anyway, a new check showed 2 sec - 765kN and
> 5 sec - 2657 kN, much better figures.
> Strange is that Crafty 18.03 seems to reach 1.Kc3 faster
> in Deep Fritz GUI than Fritz6 GUI... In DF 1.Kc3 was chosen after 4 sec with
> 2135 kN. Much better. Have to be careful with these things... ;)
>
> Thanks
> Sune


That always worries me.  It should behave the same no matter which GUI is
used, unles the GUI is doing something it ought not be doing...



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