Author: Rex
Date: 11:56:46 10/08/02
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Explained well. Thank you. On October 08, 2002 at 14:37:39, Robert Hyatt wrote: >On October 08, 2002 at 14:29:02, Rex wrote: > >>I agree that dual or more processors are faster. My question is the effeciency >>of search may be decrease. The weight of a given move may be decreased when its >>way down the tree. The differences of move weight gets less efficiant when the >>tree search gets deeper and deeper. Calculating what would be the best move >>based on score may not be the best move at all. Figuring this calculation deep >>in the search tree is probably imposible until that particular move arrives 1 to >>2 moves deep. Then it may be too late. > > >By faster, I don't mean "faster NPS only". > >I mean that if it takes one 1ghz processor 3 minutes to search to depth X, then >the two >1ghz machine should take significantly less than 3 minutes to reach that same >depth X. > >For Crafty, the rough number is about 1.7. IE if it takes 3 minutes for one >cpu, then it will >take around 1.7 minutes to do the same search using two cpus. For Crafty, the >NPS will >be closer to 2x faster using two cpus, but the "search efficiency" you mentioned >drops >the overall performance gain down to 1.7X or so... (again, this is an _average_ >number, >for those that like to question it. Some positions speed up more than 2.0 times >faster, >other speed up significanly less than 2.0 times faster. The overall _average_ >seems to >hover around 1.7 for Crafty. YMMV on other programs or on different hardware.)
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