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Subject: Re: Question: Where do you set your null move threashold?

Author: Peter McKenzie

Date: 20:54:44 11/14/99

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On November 14, 1999 at 22:58:19, James Robertson wrote:

>On November 14, 1999 at 22:16:33, Will Singleton wrote:
>
>>On November 14, 1999 at 21:45:26, William Bryant wrote:
>>
>>>I recently found that my null threashold is set to low, and I am experimenting
>>>with different level.
>>>
>>>I am curious what other people have found works for them.
>>>
>>>Do you count pieces or pieces and pawns?
>>>
>>>How may pieces or pieces and pawns must be present for the side on move
>>>to allow a null move?

Latest ICCA journal has an article by Ernst Heinz (Darkthought) about 'Adaptive
Nullmove Pruning'.  Basically he uses R=3 near the root, and R=2 for the last 6
plies.  He seems to think this is a good practical combination (reduces nodes,
doesn't make too many tactical mistakes) and does some experiments to suggest it
is better that straight R=2 or R=3.

cheers,
Peter

>>>
>>>Thanks in advance.
>>>
>>>William
>>>wbryant@ix.netcom.com
>>
>>I originally had a threshold of around 3 pieces per side, but now I allow
>>endgames as long as someone has a piece.  This is further modified by a
>>blocked-pawn term, which disallows null if most pawns are blocked.  I think.
>>So, I don't detect zug like some others attempt to do.
>>
>>I only use R=2, but I know others alternate between 2 and 3 depending on the
>>situation.
>>
>>Will
>
>What are the advantages/disadvantages of alternating between R=2/3? Does having
>some entries with R=3 cause problems with the hash table?
>
>James



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