Author: Vincent Diepeveen
Date: 08:50:40 09/18/01
Go up one level in this thread
On September 18, 2001 at 11:31:00, Robert Hyatt wrote: >On September 18, 2001 at 09:10:02, Vincent Diepeveen wrote: > >>On September 17, 2001 at 12:00:45, Gian-Carlo Pascutto wrote: >> >>Hello now that i saw this link and downloaded the source i >>realized this was also published in advances in ICCA volume 8, >>of course i got this book and first removed some dust from it, >>after which i opened it and saw at page 71 claimed next >>by M. Brockington and J. Schaeffer >> >>"... Although most parallel alfabeta-programs take months to develop, >>the game-independant library allows users to integrate parallellism >>into their application with only a few hours of work" >> >>[cough] >> >>Well if no one here manages to do that, who am i to say that the >>remainder of this algorithm is worth trying? >> >>For sure there is a speedup problem. >> >>But there is more. It's a complete different algorithm than YBW. >> >>Which means that APHID already says who has to search what before relevance >>of parallel splitting has been indicated. Considering that nowadays we >>use nullmove bigtime, this makes APHID completely outdated, because >>it in short doesn't wait at all! > > >You need to _read_ the article first. That version of Crafty used null-move >R=2, recursively. Changing to R=2-3 would be a trivial change. Bob the speedups claimed are for serach depth from 5 ply to 8 ply MAXIMUM. Based entirely upon a program called > >> >>First few pages it says that a major problem with YBW is the idle time. >> >>This refers to the fact that YBW for each node needs a result for the >>first move first before splitting other moves. Now this is of course very >>true, but this directly also shows that APHIDs branching factor is by >>definition bigger than algorithms which use YBW. >this is incorrect. Cray Blitz didn't use YBW either. It tried to do that >whenever possible, but it _never_ waited, _ever_. It would choose to split I'm doing that partly too, but i directly resplit if possible then, so i see DIEP like a program which splitting strategy is completely YBW dominated. Did you resplit in Cray Blitz when possible? >_somewhere_ rather than sitting idle, taking a chance that the parallel work >done was needed. >>Back in 1996 for example TheTurk which used APHID searched 2500 nodes >>a second. I don't need to mention that for nowadays networks capable >>of searching millions of nodes a second, that branching factor is a bigger >>problem than it used to be in 1997. >> >>Note that Deep Blue used seemingly a similar approach to APHID, which >>considering its search depth was no problem to use of course. > > > >Deep Blue's search was not related to the APHID approach in any fashion. Their >search was completely different for obvious hardware reasons. The explanation given by Hsu in IEEE99 is pretty similar to the story the APHID guys give... > >> >>>On September 17, 2001 at 11:54:35, Vincent Diepeveen wrote: >>>>On September 17, 2001 at 07:10:46, Gian-Carlo Pascutto wrote: >>>> >>>>Well show me the code and i can run it here at my 100mbit >>>>network then! >>> >>>ftp://ftp.cs.ualberta.ca/pub/games/aphid >>> >>>APHID libs, crafty version for them >>> >>>You need PVM (Parallel Virtual Machine, standard message-passing >>>lib), and probably a quick look at some of their docs how >>>to set up the config files. >>> >>>You can get the papers/thesis and all from >>> >>>http://www.cs.ualberta.ca/~games/aphid/index.html >>> >>>-- >>>GCP
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