Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Null Move Heuristic - Comments Please (somewhat long)

Author: Dave Gomboc

Date: 22:03:21 05/14/99

Go up one level in this thread


On May 15, 1999 at 00:47:12, James Swafford wrote:

>On May 15, 1999 at 00:34:35, Dave Gomboc wrote:
>
>>On May 14, 1999 at 20:10:09, William Bryant wrote:
>>
>>>I'm ready to ruin a perfectly good search by adding more code. If done right,
>>>the Null move should make it much stronger.  My copy of C. Donningers paper has
>>>been ordered by inter library loan so I have not yet read the paper.  Below is a
>>>summary or digest of information available from this forum over the last year
>>>concerning null moves.
>>>
>>>I think this is a pretty up to date summary of the heuristic, but would
>>>appreaciate any comments.
>>>
>>>Note: I have assembled this from many posts, maybe even yours.  I claim no
>>>copyright on the material.  For those, like me, ready to expand their programs
>>>with Null move search, I hope this summary helps.  Please feel free to correct
>>>any errors I might have made.
>>>
>>>William
>>>wbryant@ix.netcom.com
>>>
>>>Null Move Summary
>>>
>>>Description
>>>	Null moves are a forward pruning mechanism to generate a beta cutoff without
>>>doing a full search
>>>
>>>Situations to Avoid Null Moves
>>>1. When the side on move is in check. Then a null move simply allows the other
>>>side to capture the King.
>>>2. Having just done a null move.
>>
>>I have heard this restriction before, but I have also heard that it is fine to
>>do this, because one or the other null-move will fail.  Does this make any
>>sense?  I have not spent much time thinking about it.
>>
>>Dave
>
>
>Suppose you're in Search( ) with depth remaining=7.
>Now you start a null search w/ a reduction of 2, so
>you're in search again with depth=5.
>
>Now repeat.  Repeat again.
>Soon enough you're in quiescence, and you might as well
>have set r to 7.
>
>--
>James

Are recursive null-moves normally done without limit?  I was under the
impression that a maximum number per continuation were allowed. ?!

Dave



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.