Author: Vincent Diepeveen
Date: 03:34:43 10/14/02
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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 :) 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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