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Subject: Re: "ALL node" definition

Author: Dezhi Zhao

Date: 13:44:10 02/22/03

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On February 21, 2003 at 23:48:52, Robert Hyatt wrote:

>On February 21, 2003 at 13:26:34, Alvaro Jose Povoa Cardoso wrote:
>>Could someone please define what "ALL node" is and axplain how do we process
>>these type of nodes?
>>Best regards,
>>Alvaro Cardoso
>If you look at a perfectly ordered alpha/beta tree, after you search the first
>branch at a node to establish alpha, you search the rest of the branches, and
>at each successor you search only one node (the refutation move).  But at the
>next ply below that you have to search _all_ moves.  This alternates down
>through the tree.  At "all" nodes, move ordering is totally irrelevant.  At
>successors to all nodes, you get "cut" nodes where you only need to search one
>move, if you can search a good move first...

Dr. Hyatt,

I am considering the case with transpostion table. At ALL node, is move ordering
still irrelevant with tree size or search time? I think move ordering could
still play a role here. Imagine you start with move_a that leads to a new
poistion and forces many replacements. Later you search move_b whose subtree
position entry was just overwriten. If you had started with move_b, you could
have returend immeadiately with a hit.

In this case, moves could be sorted by transpostion hits or other criteria to
maximize utilization of transpostion table, instead of possibility of cut-off.
Has anybody spent some effort on this?


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