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Subject: Re: Wierdness with crafty tablebases.. also has to do with fritz engine.

Author: Matthew Herman

Date: 11:32:36 12/13/98

Go up one level in this thread


On December 13, 1998 at 10:11:16, Robert Hyatt wrote:

>On December 13, 1998 at 08:18:34, Matthew Herman wrote:
>
>>On December 13, 1998 at 00:22:27, Robert Hyatt wrote:
>>
>>>On December 12, 1998 at 20:09:19, Matthew Herman wrote:
>>>
>>>>I recently compiled the tablebases for Crafty 16.1 (eugene nalimov format). Then
>>>>I created the crafty.eng (with the winboard.eng). Then I showed it a KBNK
>>>>position .. great it found the stuff from the tablebase.. then I showed it a
>>>>KRKB position and it didn't!?!?! what gives?? Please shed further light.. thanks
>>>>
>>>>P.S. This also happened on winboard..
>>>>
>>>>Matt
>>>
>>>
>>>do you see files krkb.nbb and krkb.nbw in the directory?  If not, that
>>>is the problem...
>>
>>Yes, I generated all of them into that folder.. and I do see it. Also KRKN
>>doesn't work either. It's that some work and some don't
>
>
>Just a minute... I forgot about something.  Check your log.nnn files for games
>like KR vs KN.  Look at the top, before the start of the search, to see if you
>see the message "drawn at root, trying for a swindle."
>
>that means this is a known tablebase position, that with best play it is a
>draw, but crafty has a material advantage.  Rather than just playing any move
>that leads to a draw, based on randomly which move it searches first, which
>might well choose RxN as the move to play, even if KxR is the reply.  This
>"swindle" mode does a normal search instead, but *only* considering the moves
>that lead to a draw..  which lets it make the draw as difficult as possible for
>the opponent.  IE ie KRP vs KR, many are draws, and in choosing a position from
>the tablebases with a score of 0, it might give up the pawn and make the draw
>trivial.  Now it holds on to the pawn as long as possible to give the opponent
>a chance to make a mistake and take the draw into a won position for crafty...
>
>Bob

Umm yes thats nice and I found it in the log files.. but HOW can I see that
analysis .. should I assume then it is drawn? what if there is one drawing move
in the position?? Crafty will say that drawn at root, trying for swindle and I
wont get to see what that only move is?

Thanks,

P.S.

Awesome program! When are you getting the quad xeoN?



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