Author: Uri Blass
Date: 14:08:28 10/04/01
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On October 04, 2001 at 14:49:37, Robert Hyatt wrote: >On October 04, 2001 at 07:09:30, Uri Blass wrote: > >>On October 04, 2001 at 06:46:48, Sune Fischer wrote: >> >>>On October 04, 2001 at 04:56:08, Uri Blass wrote: >>> >>>>The difference is that the other side(I and Bruce) do not say that they know >>>>that there is a super linear improvement but that we cannot say that it is >>>>impossible with the known algorithm of today. >>>> >>>>I said that the only way is to investigate the problem by test positions in >>>>order to see if programs can get a super linear improvement from 2 processors. >>> >>>But that is not the only way, you can also use logic. >>>This is like explaning to an inventor why he can't make a perpetuum mobile >>>machine. If he doesn't understand the laws of physics, does not know of energy >>>conservation, then he will keep arguing till the day he die, that "we can not >>>know for certain until we have tried everything". >>> >>>We _do_ know, there is proof and Bob has outlined it several times, but if you >>>won't listen or understand, then we have a communication problem. >>> >>>-S. >> >>There is no proof when we do not know the source code of Deep fritz. > > > >Please go find _any_ book that discusses "the analysis of parallel algorithms" >somewhere in it. You will find a very detailed discussion of this stuff with >mathematical analysis of why it is impossible. It has nothing to do with a >specific algorithm. > >It has _everything_ to do with the simple proof of the statement "A two-tape >turing machine has no more computational power than a one-tape turing machine." > >Once you read and understand that, there is no need to discuss the concept >further. IE I _know_ there is no way to do a sort in less than O(N) >complexity, because It takes N cycles just to read the input. And in reality, >I know that there is no way to do a sort in < o(N log N) cycles. This has >_also_ been proven beyond a shadow of a doubt. To say "that isn't true because >we have not tried all possible sort algorithms" won't fly. > > > >> >>There is an agreement that a poor sequential algorithm can be more than 2 times >>slower than a good parallel algorithm with 2 procesors. > >Only in special cases... > >> >>We do not know that the algorithm of Deep Fritz for one processor is not poor >> > >Who cares. It is the _same_ algorithm used on 2 processors. _exactly_ the >same. Same alpha/beta algorithm. Same evaluation. Same move ordering. Etc.. Same move ordering does not seems to me to be truth. Uri
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