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Subject: Re: Nullmove killers

Author: Robert Hyatt

Date: 15:06:10 06/23/99

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On June 23, 1999 at 15:46:25, Daniel Karlsson wrote:

>I've been trying a new (at least it's new to me) move ordering heuristic and I
>wanted to see what the rest of you think about it.
>
>When I do a nullmove and it fails to produce a cutoff (on [beta - 1, beta]), I
>take the refuting move and use it sort of like a killer move for the next ply.
>This "nullmove killer" is searched before the other killers. This seems to
>reduce the tree by about 3% or so (7 ply search), but my program and hardware
>are too slow to do any exhaustive testing (or rather, I'm too impatient).
>
>Has this or something similar been tried by others? Was it any good? Is it plain
>stupid? Any comments appreciated.


It would seem to me that this happens 'naturally'.  IF one move causes the
null-move search to fail low, then that move must have failed high and _must_
be in the killer table from doing so?




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