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Subject: Re: A Null Move Enhancement?

Author: Dann Corbit

Date: 16:00:03 02/10/99

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On February 10, 1999 at 17:20:34, Dan Homan wrote:
>This is a very interesting observation.  Maybe it would be right to
>say that null move might be a "waste" of time if the material score
>is not close to beta?  Taken a step further... some kind of a "windowed"
>null-move might be a good idea.
>I tried this in my program.  I changed my null move code so that
>a null move would only be tried *only* if the material score for the side
>to move was greater than (beta-1.5*pawn_value).  This reduced my
>searched nodes from 5-10% in most of the positions I have tried so
>far.  (I have only tried a handful of WAC positions so far.)
>If this pans out, It is a perfectly safe enhancement to
>null-move.  The 1.5 pawn window that I tried was arbitrary;
>another value might do better.
What an incredibly creative idea!
I have thought that it might be interesting to do something like this, but slide
the window as we go forward.  In other words, instead of a single value, use a
value that is a function of the plies of the search.

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