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Subject: Re: Difficult position for programs, at least for Crafty.

Author: Robert Hyatt

Date: 07:12:09 08/11/99

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On August 11, 1999 at 03:35:12, Bernhard Bauer wrote:

>On August 10, 1999 at 12:00:07, Robert Hyatt wrote:
>
>>On August 10, 1999 at 10:44:49, Bernhard Bauer wrote:
>>
>>>On August 10, 1999 at 10:24:30, Robert Hyatt wrote:
>>>
>>>>On August 10, 1999 at 02:25:56, Bernhard Bauer wrote:
>>>>
>>>>>On August 09, 1999 at 12:24:56, Robert Hyatt wrote:
>>>>>
>>>>>>On August 09, 1999 at 10:02:42, Bernhard Bauer wrote:
>>>>>>
>>>>>>>Hallo,
>>>>>>>
>>>>>>>recently I came across a position from a game
>>>>>>>Haenninnen - Szabo, Wageningen.
>>>>>>>
>>>>>>>The position is
>>>>>>>FEN: 3r1rk/pp1q2b/3p2pp/PP1Np2n/2Pp1p/B2P2Pb/3QPPBP/R4RK w
>>>>>>>
>>>>>>>The game went on
>>>>>>>19. Bxd6 Bxg2
>>>>>>>20. Bxf8 Qh3
>>>>>>>21. Bxg7 f3
>>>>>>>22. exf3 Bxf3
>>>>>>>23. Ne3  Kg7
>>>>>>>24. Qb4  Rd7
>>>>>>>25. Ra2  Nf6
>>>>>>>White resigned.
>>>>>>>
>>>>>>>Programs have difficulties to find out that 19. Bxd6 is bad.
>>>>>>>The whole line seems to be difficult at least for Crafty.
>>>>>>>BTW Crafty produces a lot of debug messages on a Sun, not on a PC.
>>>>>>>
>>>>>>>Enjoy
>>>>>>>Bernhard
>>>>>>
>>>>>>
>>>>>>What is "a lot of debug messages"?  If you are getting oddball error messages
>>>>>>then something is definitely wrong...
>>>>>>
>>>>>Messages like this:
>>>>>captured a king
>>>>>piece=5,from=51,to=44,captured=3
>>>>>ply=16
>>>>>My logfile is 5.2 Mb in size.
>>>>>
>>>>>
>>>>>>As far as the position goes, the end has a B on F3, Q on h3, which is a known
>>>>>>"null-move" killer...
>>>>>
>>>>>Oh, not known to me. But I feared it would be a null move problem again -:)
>>>>>Kind regards
>>>>>Bernhard
>>>>
>>>>
>>>>That is definitely bad.  Such errors should never occur, and are only present
>>>>to catch errors that I introduce when changing the code...  Can you post a
>>>>FEN for aposition that will produce such an error?
>>>
>>>Of course
>>>FEN: 3r1rk/pp1q2b/3p2pp/PP1Np2n/2Pp1p/B2P2Pb/3QPPBP/R4RK w
>>>See above.
>>>
>>>BTW the hardware is a Ultra Sparc with 2 procs.
>>>fpversion gives:
>>> A SPARC-based CPU is available.
>>> CPU's clock rate appears to be approximately 166.8 MHz.
>>> Kernel says CPU's clock rate is 168.0 MHz.
>>> Kernel says main memory's clock rate is 84.0 MHz.
>>>
>>> Sun-4 floating-point controller version 0 found.
>>> An UltraSPARC chip is available.
>>> FPU's frequency appears to be approximately 170.5 MHz.
>>>
>>> Use "-xtarget=ultra" code-generation option.
>>>
>>>The OS is Solaris 7 from May 99. It's the 64-bit version.
>>>The compiler is gcc2.95
>>>
>>>Kind regards
>>>Bernhard
>>
>>
>>OK.. I overlooked that this was the same position discussed earlier.  I ran this
>>a bunch of times with no strange output at all.  I'd guess that somehow the
>>optimizations are going wrong...  try compiling without the -O at all, and then
>>run the same test.  And keep adding optimizations back in until you do see the
>>error.
>>
>>I ran with 1 cpu, 4 cpus, long and short search times, with none of that
>>'captured a king' internal diagnostic error stuff at all...
>
>Here my results.
>Without -O , but with assembler code Crafty produces "captured a kink".
>Without -O , and without assembler code Crafty looks fine.
>With    -O3, and without assembler code Crafty dumps core from beginning.
>
>May be the Sparc assembler code does'nt fit my system, or somthing is wrong for
>target=SUN, since Crafty runs well under WinNT.
>
>Kind regards
>Bernhard


For comparison, are you using the SUN option in the Makefile?  Also, if you
use the sparc assembly code, you _must_ use COMPACT_ATTACKS as the sparc
assembly depends on that.

A friend of mine is running a sparc version on an ultra-sparc 300, and isn't
seeing this, although I am going to test your position on it to see if I see
any errors...



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