Re: swapoff function?

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Article #2172

#2172

From: Simon Waters
Date: Tue, 26 Dec 2000 17:29

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mink wrote:
> 
> I try to understand the logic used in swapoff function ( the one used to
> give the score to the generated move ) but still don't have any luck. Can
> anyone here explain me in detail ?

Swapoff is used to determine if it is safe to capture without actually
growing the tree of possible moves.

The idea being; if I can capture on a square with 2 pawns and you can
capture only with pieces - even if I capture first I'll come out ahead
in an exchange. So we calculate all the captures and order by the value
of the capturing piece.

It is used to order moves from the move generator as it helps make sure
more of the search time is spent on captures that win rather than lose
material.

My experience with the code suggests that there may be less
computationally complex ways of ordering moves, that may be as
beneficial, or more so, than the swapoff. As the results of test cases
have proved sensitive to minor changes to the code in sort.c

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From: Simon Waters <Simon@wretched.demon.co.uk>
Newsgroups: gnu.chess
Subject: Re: swapoff function?
Date: Tue, 26 Dec 2000 17:29:52 +0000
Organization: Eighth Layer Limited
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