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Subject: Re: singular extension (more) - oups i have it

Author: Robert Hyatt

Date: 16:48:03 09/15/04

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On September 15, 2004 at 18:42:50, Gerd Isenberg wrote:

>On September 15, 2004 at 18:30:56, Gerd Isenberg wrote:
>
>><snip>
>>>>>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.
>>>
>>>That is crude.  The problem is that suppose you are wrong at ply=2.  That causes
>>>you to mis-categorize every node below that because when you are wrong at ply=2,
>>>for non-PV ply=1 moves, it suggests that either the current ply-1 move is better
>>>than the best so far and you are changing your mind, or that the current ply=2
>>>move is not the best and another move will cause a cutoff.  But below that ply=2
>>>move that is normally a CUT node, ply=3 would normally be an ALL node, but that
>>>changes since the ply=2 node is wrong.
>
>i have your point, but anyway that are probably nodes of some interest, if the
>formal node categorizer contradicts eval (or even reduced search) bound compare
>in some way.


That was what I spent a lot of time on in the DTS "where to split" code in CB.
I first did a simple analysis to type each node, going root to tip, then I
looked for inconsistencies from tip to root to see if I could pick up on where I
blew move ordering which means splitting the tree in that area is dangerous...



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