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Subject: Re: Thanks for explanation!

Author: Jeff Lischer

Date: 05:08:55 11/19/01

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On November 19, 2001 at 00:29:28, Robert Hyatt wrote:

>On November 18, 2001 at 12:09:10, Jeff Lischer wrote:
>
>>On November 18, 2001 at 10:03:15, piet de hoop wrote:
>>
>>>The next position occured in Diep versus Rebel Century 4 round 6 of the Dutch
>>>Open Computer Chess 2001
>>>
>>>[D] 8/6p1/3k3p/8/3K4/7P/8/8 b - - 0 43
>>>
>>>The result was a draw, but for some computerprograms I tried, the evaluation was
>>>from -1 to -3.4 pawn. (Fritz 6.0, Crafty,Yace)
>>>
>>>I expect that programs equipped with the right pawntable base have no problem
>>>with this position, but i expected that programs without these tablebase while
>>>calculating over 30 plys or more should give the right evalution?
>>>
>>>Or do i miss something?
>>>
>>>Piet
>>
>>When I tried this position with programs using all 3,4, and 5 piece tablebases
>>they saw the draw immediately.
>>
>>The only oddity was Crafty. I was using Crafty 18.12 in WinBoard 4.2.3. When
>>Crafty played White, it saw the draw in tablebases and moved immediately. When
>>it was Black, however, it did not see the draw in tablebases. Instead it anayzed
>>the position as it normally would and gave Black a 2-3 pawn advantage. Other
>>programs (Yace, Gandalf) worked fine in WinBoard as both White and Black.
>>
>>Is this the intended behavior for Crafty or a bug? If it is intended, why?
>
>
>Normal.  It is called "swindle mode" and can be turned off with "swindle=off"
>in the crafty.rc file.
>
>The idea is that if you are ahead in material, but it is drawn, it is better
>to search and keep the material waiting for an opponent mistake, rather than
>giving up the extra material into an even easier-to-draw position.
>
>This has been discussed here dozens of times...

Thanks. Makes perfect sense :)



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