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Subject: Re: Extending Checks

Author: Rick Bischoff

Date: 21:05:06 09/10/04

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You already count your legal moves through the loop-- that is how you determine
mates, right?  Why not, instead of just having a bool variable for
legalMoveFound, change it to an integer.  Then, mark the move with a special
"only legal move bit"-- on the next iteration (with iterative deepining) or
maybe in the same loop.

On September 10, 2004 at 21:35:58, Stuart Cracraft wrote:

>I read, somewhere, and I forget who, about
>if 1 legal move, extend 2 ply,
>2 or more legal moves, then 1 ply.
>Anyone have any stats on the effects
>on play of the above instead of
>always extend 1 legal move. Does it
>blow up?
>
>How do people get around the cost
>of determining that there is only
>1 legal move?
>
>For me, that's an expensive operation
>involving usually dozens of makemove/unmakemove's
>with a test to see if the king is attacked,
>at every single node, before doing the search
>of the 1 move with the increased depth.
>
>Only rarely is it just 1 legal move to get
>out of check. But the determination of that
>is not rare. It has to be done for every
>sweep of the moves at each node.
>
>Thanks,
>
>Stuart



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