Author: Robert Hyatt
Date: 07:32:09 09/25/01
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On September 25, 2001 at 09:37:08, Dieter Buerssner wrote: >Another idea. Often, when you fail high, actually more than one will fail high. >An unrealistic example. Assume at a certain depth, in nodes that will fail high, >they will either use about 10000 nodes or 1 node to fail high (because of a hash >hit). If you search one after the other, you will randomly pick one or the >other. On average 5000 nodes. If you search the first 2 moves in parallel, you >will much more often get a very fast cutoff. > That "much more often" is wrong. Much more often you simply search the first move and get a cutoff, while you are searching the second. That is called "search overhead" as your parallel search just searched something that the serial search avoided. That _kills_ performance, and is the very reason no one wants to search in parallel at any node we suspect has even a chance of failing high. Hence young-brothers-wait and similar algorithms... >Have I invented ETC now? :-) > >Regards, >Dieter
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