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Subject: Re: singular extension

Author: Alessandro Scotti

Date: 13:14:34 09/15/04

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On September 15, 2004 at 15:54:40, Gerd Isenberg wrote:

>I'm interested in some statistics, how often cut-nodes behave all-like (eval
>fails, first fails, all fail), same for all nodes with cuts and this correlates
>with branching factor - and the influence of several move ordering heuristics.

One interesting paper is "Multi-Cut AlphaBeta-Pruning in Game Tree Search" by
Bjornsson and Marsland.

>Hmm, is it worth to update node types incrementally during search?
>I guess with a counter of played pv-moves (0..N) in the top of the current path
>and ply index one may determine the minimal tree node type as well...
>So we have distance D of the current node to the last pv node in the current
>path.
>
>If D == zero we have a pv-node.
>If D is odd we have a cut node.
>If D is even and greater zero we have an all node.

IIRC, however, one of the children of a pv-node is another pv-node. Also, when
dealing with null window searches there are no pv-nodes but only alternating
layers of cut and all nodes.



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