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Subject: Re: 8 WAC toughies at long time control - WAC 230

Author: Dann Corbit

Date: 10:51:43 03/16/01

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On March 16, 2001 at 09:47:09, Robert Hyatt wrote:
[snip]
>Blocked pawns are not so hard to find.  Crafty has some code that does this
>extremely accurately, to try to prevent these from happening.  It builds a
>big bitmap of squares that pawns can move to, which takes into account how
>many pawns attack and defend each square.  This way it doesn't have to have
>two pawns rammed together to know they are blocked.
>
>It is still hard to figure out what to do, of course.  Right now I simply
>penalize the score when there are lots of pawns and few or no lever
>possibilities...

Why not simply set the eval to 0.0 when you have a complete blockade, or eval -
piece_value when you have just a blocked piece?  That way, the eval function
will automatically find ways to unblock it.

Benefits:
If you are behind, the engine will try to keep it blocked.  That's what you
would want to happen in this situation.  So it helps you fight for the draw.  If
you are ahead, then it will consider the value of crashing the barricade to be
just slightly less than your current material advantage.  Again, I think this is
exactly what it ought to do.

So if there is a wall between you and your opponent, then the eval is 0.0.  I
think that solves all the wall problems.



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