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Subject: Re: Crafty Bug? (more)

Author: Robert Hyatt

Date: 12:05:08 08/14/02

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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.




>
>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...




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



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