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Subject: Re: Inappropriate tablebase usage

Author: Bruce Moreland

Date: 15:36:11 08/24/00

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On August 24, 2000 at 17:37:31, Hugh Cumper wrote:

>Wanting to practice some simple endings I set up R+P V R and gave Fritz the
>stronger side. I was surprised that it was giving me very easy draws, sometimes
>repeating moves or else allowing the rook exchange with an obviously drawn pawn
>ending. The reason was that the tablebase told it the position could not be won
>so it regarded all moves (that didn't blunder the rook) as equivalent. When I
>disabled the tablebase access it gave me a much harder time. Wouldn't it be
>better to use the engine to find a constructive move in a case like this, just
>using the tablebase to check both sides moves for outright errors? It may be
>that anyone who loses such a simple ending would be too weak to get into one
>against a computer but this is surely not true of R+B V R or B+B V N.
>I believe other tablebase enabled programs do the same thing, unless anyone
>knows different.

Yes, this is an incomplete implementation.  The proper thing to do is, once you
are in the tables, probe the tables to see if the game is a win, and if so
return the proper score.  If not, you hit the heuristic eval function and return
that.

bruce



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