Author: Robert Hyatt
Date: 06:53:27 09/25/01
Go up one level in this thread
On September 25, 2001 at 07:21:29, Vincent Diepeveen wrote: >On September 25, 2001 at 00:38:36, Robert Hyatt wrote: > >>On September 24, 2001 at 22:30:26, Vincent Diepeveen wrote: >> >>>Hello, >>> >>>Here written down speedups as claimed by a guy called R. Hyatt >>>by cray blitz for 24 different positoins as they occured in >>>a game: >>> >>>pos speedup >>>1 2.0 >>>2 2.0 >>>3 2.0 >>>4 2.0 >>>5 2.0 >>>6 2.0 >>>7 1.9 >>>8 2.0 >>>9 2.0 >>>10 2.0 >>>11 2.0 >>>12 1.9 >>>13 1.9 >>>14 2.0 >>>15 2.0 >>>16 1.9 >>>17 1.7 >>>18 1.8 >>>19 2.0 >>>20 2.0 >>>21 2.0 >>>22 1.9 >>>23 2.0 >>>24 2.0 >>>avg 2.0 >> >>Please re-do your math. No way to average 2.0 with even _one_ value that >>is < 2.0 >> >>There are several above that are less than 2.0 > >Page 16 at ICCA journal March 1997 you claim >Average for 2 processors 2.0 OK. rounding. the actual value above is 40 - 1 / 20 = 39/20 = 1.95. > >>>So YOU, Robert Hyatt, claims in an OFFICIAL magazine, >>>called ICCA journal march 1997, >>>an AVERAGE speedup of 2.0 with cray blitz at 2 processors. >>> >> >>I don't see an average of 2.0... >> >> >> >>>Now i claim the same with DIEP if i'm not using dangerous >>>extensions (which btw are turned on by default). >> >>No... You claim > 2.0 which is not possible over a set of positions. Unless >>your sequential search is simply badly flawed. Then it doesn't matter. Go get >>a copy of my Ph.D. dissertation. I proved quite clearly that for a minimax >>search (alpha/beta with worst-possible ordering) it is possible to get a >>near-perfect speedup curve. I also proved that with perfect ordering, the >>same is possible. But The real point was that I clearly proved that we can't >>get perfect move ordering (for obvious reasons) so that for normal cases, an >>optimal (4.0 using 4 cpus) is not possible. > >The only time when i got close to 4.0 at 4 processors was when i >forward pruned in a very dubious way. That was at world champs. I get close to 4.0 all the time. Just not _every_ time. The average is in the 3.2-3.3 range for test sets, maybe 3.2-3.5 for real games. But there are those exceptions that drag the average down. > >Nowadays versions i'm pretty sure i'm not even close to the 3.7 which >you had with Cray Blitz. Of course at the Quad i only ran with versions >which have turned on dubious extensions by default. > >I have no idea what a run longer than say 10 minutes gives for kind of >speedup, but i can imagine very well that because of reasons written down >here, that it won't be good. > >For parallellism, running on 2 processors is perfect! 1 is even better. there will _never_ be any "search overhead". > >> >> >> >> >>> >>>It appears you hadn't turned them on either (smart guy >>>to publish only speedups without dangerous extensions and only >>>tell in 2001 that you hadn't turned them on). >> >>I was supposed to tell I hadn't turned on something I was not using because >>it caused a serious problem??? I don't follow that logic. And I don't consider >>the SE as "a dangerous extension". I don't do "dangerous extensions" anywhere >>in my code, either now or then...
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.