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Subject: Re: Highly confusing tablebase behavior :)

Author: Pete R.

Date: 09:17:18 08/20/99

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On August 19, 1999 at 21:10:35, Robert Hyatt wrote:

>On August 19, 1999 at 17:24:20, Pete R. wrote:
>
>>On August 19, 1999 at 15:13:23, Robert Hyatt wrote:
>>
>>>On August 18, 1999 at 20:35:00, Pete R. wrote:
>>>
>>>>I have a position as follows: white has king and rook, black has king knight and
>>>>pawn. I have the knpkr tablebase files.  When it's black to move, the tablebase
>>>>returns the value instantly.  However when it's white to move the program thinks
>>>>while doing tablebase hits, presumably on the 4 man set.  Evidently I don't
>>>>understand tablebase files, so could someone explain to me what's going on here?
>>>>Knpkr only applies to white having knp??
>>>
>>>
>>>Are you talking about crafty here?  If so, look to see if you see "drawn at
>>>root, trying for swindle..." in the output, or else do "swindle off" to disable
>>>"swindle mode"
>>>
>>>If the position is a draw at the root, crafty tries a search to give you a
>>>chance to make a mistake and lose.
>>
>>I just posted below on that before reading your response.  I did see the "drawn
>>at root, trying for swindle" when I kicked it out of analyze move.  I just
>>repeated the test in analyze mode with a kbpkr position with white have k+r.
>>Even though I tell Crafty to analyze, when it's on analyze.white, I put in a
>>move and it returns immediately with no depth, time, score, or variation values.
>> Then on analyze.black I make a random move and it comes back instantly with an
>>EGTB move and a score like MAT20.  Then I make the suggested move on
>>analyze.white and again nothing is returned.  This happens even with swindle
>>off.
>>
>>In the Chessbase interface the behavior for both Hiarcs and Crafty is similar to
>>this, when one side is on move the 5 piece tablebase is hit instantly, on the
>>other side it starts analyzing, while getting thousands of tablebase hits, which
>>must be on the 4 man subset.  ??
>
>
>First, I guess that means that ChessBase likes the way I handle tablebases,
>if they copied it.  :)
>
>As far as the rest of your question, it depends.  If you are using the
>chessbase CD, it doesn't have anywhere near all of the 5 piece files, so
>anything can happen.  The only time crafty does a search is when the position
>is a draw and it wants to give you a chance to make a mistake...  Otherwise, no
>ideas...

I have all the 4 man and downloaded a bunch of 5 man sets from your site.  For
example I have kbpkr.nbb.emd and kbpkr.nbw.emd.  I set up a kbpkr situation, and
set Crafty to analyze mode.  When I make a move for one side, I get the EGTB
value returned, e.g. MAT19. But then when I make a move for the other side, no
EGTB value is returned.  I suppose this isn't strictly necessary in analyze
mode, but it is a bit confusing.  This happens whether or not swindle is on. For
the Chessbase engine versions of Crafty and Hiarcs this sort of behavior must be
the default.



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