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Subject: Re: Highly confusing tablebase behavior :)

Author: Robert Hyatt

Date: 18:10:35 08/19/99

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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...







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