Author: Robert Hyatt
Date: 11:49:37 10/04/01
Go up one level in this thread
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.. >It is good enough to lead the ssdf list but it does not prove that it cannot be >improved and it is possible that the programmers of Deep Fritz even do not know >that it is possible to improve it at long time control because they did not test >it for that purpose because they were interested at tournament time control and >not at slower time control. > >In the positions that I posted Deep Fritz needs a long time to find the >suggested move(in some cases many hours) and always more than 20 minutes on p800 >if I remember correctly. > >Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.