Author: Robert Hyatt
Date: 10:51:25 10/14/02
Go up one level in this thread
On October 14, 2002 at 08:59:37, James Swafford wrote: >On October 14, 2002 at 06:34:43, Vincent Diepeveen wrote: > >>On October 14, 2002 at 04:29:41, Daniel Clausen wrote: >> >>>On October 13, 2002 at 22:48:10, Jeremiah Penery wrote: >>> >>>>On October 13, 2002 at 21:40:42, Robert Hyatt wrote: >>>> >>>><snip> >>>> >>>>>You are _totally_ wasting your breath... >>>> >>>>I don't mind too much wasting my breath, as long as some decent discussion comes >>>>from it. :) >>> >>>As if that ever happened on this board when the subject was related to DB. ;) >>> >>>Sargon >> >>the marketing hype created by IBM is so big that we'll never end >>talking about it, like they talked for well over 100 years about >>The Turk automata that won from Napoleon. >> >>it's pretty weird to see people argument that the thing searched 18 >>ply fullwidth based upon some mainlines, despite statements and >>theoretical impossibilities to do so :) > >Please defend that statment. Why is it theoretically impossible >to search 18 ply full width? Doing some back of the envelope >calculations, I get > 4.0^18 = 68.7 B nodes > 3.9^18 = 43.6 B nodes > 3.8^18 = 27.3 B nodes. > >(27.3 B nodes) / (.126 B/Sec) == 217 seconds < 4 minutes. > >What's impossible about a bf of 3.8 and a search of 217 seconds? >Note Hsu didn't claim 18 ply _every_ search. He said 12 ply >and up to another 6. > >-- >James I have tried that line of reasoning. No results. Even though the log from game one showed an EBF of around 4.0, Vincent will _not_ let that keep him from his appointed agenda... > > >> >>Amazingly no one ever talks about shredder here. Shredder always shows >>longer mainlines. Some years ago i had a selective search in diep which >>checked the principal variation of diep further. >> >>In the end i threw it out. >> >>Now suppose you have 480 processors idling, i'm so amazed no one can >>understand that in order to get more nodes a second, the only >>important thing, even the chat yesterday Hsu was only talking >>about nodes a second NOT about search depths, it is important to >>give them jobs. >> >>So splitting a position at the end of the pv 1 deeper is not so stupid >>here. The rest is from hashtable and extensions. >> >>The only interesting question this Jeremiah Penery guy should ask himself >>is: "WHAT WAS IBM BUSY DOING?" >> >>Answer: getting as many nodes a second as possible against kasparov >> >>Now how do you get as many as possible CPUs to work in order to >>get more nodes a second, with just a small search depth? >> >>All we know is that even at 11 ply search depths they didn't manage >>to get the full potential of the cpu's. In fact 126 MLN nodes a second >>is a lot less than 480 x 2.25 MLN nodes a second = 1.08 BLN >> >>126 MLN nodes a second is 11.7% from that. >> >>That's basically based upon the last seconds of the 3 minute search. >> >>the first few seconds not many processors had a job out of 480. >> >>So what i do then is to already let them split mainline second ply >>after root. I put a bunch of processors there, despite possibly >>getting a different alfabeta score. >> >>For a 2 processor setup that's horrible for the speedup (gives a >>very bad speedup). For 480 processors it's great, getting them >>busy is very important! >> >>In fact we see from the deepblue paper in 2001 that it was already >>taking processors from a search job if it took a bit too long to >>search it! Then it resplitted and added more cpu's. That automatically >>means that you get a longer PV. >> >>Best regards, >>Vincent
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