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Subject: Re: The Null Move Killer Killed (and an announcement)

Author: Robert Hyatt

Date: 17:00:57 09/30/04

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On September 30, 2004 at 18:28:51, Stuart Cracraft wrote:

>On September 30, 2004 at 18:04:05, Robert Hyatt wrote:
>
>>On September 30, 2004 at 14:25:34, Stuart Cracraft wrote:
>>
>>>On September 30, 2004 at 09:35:09, Robert Hyatt wrote:
>>>
>>>>On September 30, 2004 at 02:53:16, Stuart Cracraft wrote:
>>>>
>>>>>The null move killed, win-at-chess 141, has itself
>>>>>finally been killed, vanquished with the help of
>>>>>two board contributors whose combined suggestion
>>>>>led to a 17-fold reduction in time-to-solve.
>>>>>
>>>>>This posting announces those winners. First the
>>>>>stats!
>>>>>
>>>>>Now solved in 5.49 seconds on a P3 @ 1ghz it would be
>>>>>solved in under 2 seconds on more modern equipment.
>>>>>Formerly it took 95 seconds to solve.
>>>>>
>>>>>That's good enough for me. And it's good enough to win
>>>>>the $50 contest posed recently since it broke the
>>>>>10-second-and-under-barrieras posed in the contest
>>>>>posting.
>>>>>
>>>>>The search:
>>>>>
>>>>>Alpha=-1332 Beta=-531 Maxdepth=9999999 MaxTime=99999
>>>>> 1/ 9  g2f1  0.00 -953      511 g2f1 f4d5
>>>>>                                g2f1 f4d5
>>>>> 2/ 9  g2f1  0.01 -953      884
>>>>>                                g2f1 f4d5 c1g5
>>>>> 3/12  g2f1  0.06 -953    11929
>>>>>                                g2f1 f4d5 c1g5 d5f6
>>>>> 4/16  g2f1  0.39 -953    72781
>>>>>                                g2f1 f4d5 b3d5 c6d5 f1g2 d6e7
>>>>> 5/24> g2f1  3.83 -552   978925
>>>>>                                g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
>>>>> 5/25  c1f4  5.49 2260  1420038 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d
>>>>>6
>>>>>                                c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d
>>>>>6
>>>>> 6/25  c1f4  6.06 2260  1519145
>>>>>                                c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 d7d
>>>>>6
>>>>>
>>>>>And with it the announcement -- because of the contribution
>>>>>of Will Singleton in indicating that null move should be
>>>>>avoided before leaves in the main search (and the sense
>>>>>of a comparison in an old commented out section of the
>>>>>code associated with disabled null move verification having been
>>>>>intended to do what Will suggested but having been miscoded
>>>>>by me and then #ifdefed out months ago) and Uri Blass'
>>>>>comments about my recaptures being too free and easy,
>>>>>the program went from a total of 95 seconds
>>>>>for wac 141 to 5.49 after these two suggestions were
>>>>>implemented.
>>>>
>>>>I doubt null-move is the problem.  I do null-move _everywhere_ and Crafty has no
>>>>problem solving wac 141 doing so...
>>>>
>>>>
>>>>>
>>>>>So Will and Uri are the winners, if they wish to accept,
>>>>>of the divided $50 prize. Because Will's contribution was
>>>>>more significant but less work for him and Uri's contribution
>>>>>was less significant but with more work for him, but in either
>>>>>case without the change from the other's suggestion the result
>>>>>would not have been as dramatic getting down to <= 10 seconds
>>>>>as stated in the earlier contest challenge a day or two ago,
>>>>>the award has been divided in half for the 2 winners.
>>>>>
>>>>>Will and Uri are welcome to send me, and only if they wish
>>>>>to collect, their postal mail addresses, to cracraft@cox.net
>>>>>and a check for $25 will be sent out to each.
>>>>>
>>>>>In the future, more contests will be held like this whenever
>>>>>I run into a huge roadblock but I see none looming presently,
>>>>>including a rather unusual one that I am not ready to announce.
>>>>>
>>>>>Thanks everybody for the help on 141 -- and thanks to Will
>>>>>Singleton and Uri Blass.
>>>>>
>>>>>Stuart
>>>
>>>What is your quiescence like? Do you investigate moves-that-check
>>>at the first ply of quiescence?
>>
>>
>>My q-search has _no_ checks or check-evasions whatsoever.  Just captures, and
>>the captures have to appear to be at least equal using SEE or they get discarded
>>as well...
>
>What if a capture is a check or check evasion? Acceptable?
>
>Stuart


Yes, but Crafty doesn't notice this nor handle it differently as they are "just
captures" in the q-search...  q-search doesn't detect mate stalemate or draw at
all either...




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