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Subject: Re: Extend or not extend in a nullmove tree

Author: Vincent Diepeveen

Date: 04:19:31 06/08/98

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On June 08, 1998 at 03:03:37, Roland Pfister wrote:

>Last week we discussed what to do and not do in a nullmove subtree.
>My program Patzer used to not extend in such a branch. Bob argued
>against it and it sounded ok to me.

>At the weekend I tried both versions and the result is that if Patzer
>doesn't extend it is a little bit faster, but not much. But in some
>positions it sees the solution one iteration later!

>So I changed my program to extend even in nullmove branches.
>Thanks Bob.


Yes i tried about some years ago this too. It appears that when you
extend you are in fact missing all kinds of threats which in fact is the
part you wish to see.

Now i then changed my reduction factor to 3, and added some more
mating extensions, which works great.


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