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Subject: Re: Crafty Bug? (more)

Author: Slater Wold

Date: 13:45:34 08/14/02

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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?

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



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