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? dzhao
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