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Subject: Re: Crafty Bug? (more)

Author: Robert Hyatt

Date: 20:24:49 08/14/02

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On August 14, 2002 at 16:45:34, Slater Wold wrote:

>On August 14, 2002 at 15:05:08, Robert Hyatt wrote:
>
>>On August 14, 2002 at 10:51:21, Slater Wold wrote:
>>
>>>On August 14, 2002 at 10:44:00, Robert Hyatt wrote:
>>>
>>>>I have looked at this more carefully...
>>>>
>>>>There are interesting things going on that need even further analysis,
>>>>but my P3-750 notebook grabs onto b2 at 8 seconds.  But at depth=12 it
>>>>drops to draw score and sticks there until depth 14...  I am now
>>>>pretty sure this is a null-move issue because of the single tempo
>>>>that is at stake.  Both sides threaten to promote and both sides must
>>>>stop the other while advancing its plan at the same time.  A perfect
>>>>case for null-move breaking things...
>>>>
>>>>Here is the output (so far):
>>>>
>>>>         (2)   10->   5.76   1.53   1. ... Bc4 2. Re1 b2 3. Rb1 Bd3 4.
>>>>                                    Rxb2 Bxg6 5. Rb7 d5 6. Rc7+ Kd6 7.
>>>>                                    Rc8
>>>>               11     6.41   1.55   1. ... Bc4 2. Re1 b2 3. Rb1 Bd3 4.
>>>>                                    Rxb2 Bxg6 5. Rb8 d5 6. Rg8 Bf5 7. Rd8
>>>>               11     8.97     ++   1. ... b2!!
>>>>               11->  11.35   1.14   1. ... b22
>>>>               12    26.08     ++   1. ... b2!!
>>>>               12    59.32   0.00   1. ... b2 2. g7 Bh7 3. Re1 Kb4 4. Re8
>>>>                                    Ka3 5. Rb8 Ka2 6. Ra8+ Kb3 7. Rb8+
>>>>                                    Ka2
>>>>               12->   1:00   0.00   1. ... b2 2. g7 Bh7 3. Re1 Kb4 4. Re8
>>>>                                    Ka3 5. Rb8 Ka2 6. Ra8+ Kb3 7. Rb8+
>>>>                                    Ka2
>>>>               13     1:08   0.00   1. ... b2 2. g7 Bh7 3. Re1 Kb4 4. Re8
>>>>                                    Ka3 5. Rb8 Ka2 6. Ra8+ Kb3 7. Rb8+
>>>>                                    Ka2
>>>>               13->   1:10   0.00   1. ... b2 2. g7 Bh7 3. Re1 Kb4 4. Re8
>>>>                                    Ka3 5. Rb8 Ka2 6. Ra8+ Kb3 7. Rb8+
>>>>                                    Ka2
>>>N>               14     1:16     ++   1. ... b2!!
>>>
>>>So your notebook gets a better score and in better time, than my 2x1.73Ghz
>>>machine?  Ah, the beauty of SMP.
>>
>>
>>Note that I am running version 19.0, which is a bit different than yours.
>>That probably accounts for much of the difference.
>
>
>Ah!  Makes sense.  Seems like it's working, in this position anyway.
>
>>
>>
>>
>>>
>>>I see you had the display problem too.  :)
>>>
>>>I would think it would be easy to see Bh7 stops the promotion of white just long
>>>enough to promote, and of course, win.
>>>
>>>The win is deep, but it's pretty textbook.  I just thought it would be "easy"
>>>(or at least, easier) for computers.
>>
>>
>>I let it run for a _long_ time and don't see a win.  I saw scores of about
>>+2 eventually, but nothing like +9 or whatever...
>
>Do you think you can fix it?  Or perhaps help it out?  Or are you just not
>worried about it?
>

I will certainly look at it carefully tonight...



>>
>>
>>
>>>
>>>Some engines get this no problem, some don't get it at all.



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