Author: Bert van den Akker
Date: 12:29:47 11/15/99
Go up one level in this thread
On November 14, 1999 at 23:54:44, Peter McKenzie wrote:
>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
>
Here is the condition for R given in this article
2 if (depth <=6) OR ((depth <=8) AND (max_pieces_per_side < 3))
R =
3 if (depth>8) OR ((depth > 6) AND (max_pieces_per_side >= 3))
Works fine and gives 20% reduction of nodes in general
without loosing tactical strength
BvdA
>>>>
>>>>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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