Author: Robert Hyatt
Date: 10:31:49 01/17/00
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On January 17, 2000 at 09:58:10, Bas Hamstra wrote: >On January 17, 2000 at 09:32:40, Robert Hyatt wrote: > >>On January 17, 2000 at 03:11:34, Jouni Uski wrote: >> >>>Yes stunnigly they are available at: >>> >>>http://www.research.ibm.com/deepblue/watch/html/c.html >>> >>>First thing I notice is, that search depth is not very convincing at all - >>>mostly 11-12 ply (also in endgame part)! Have I read log wrong way? Most >>>Chessbase engines got same ply in standard PC... >>> >>>Jouni >> >> >>It is a "different" kind of ply. DB didn't use null-move of any kind. They >>also used singular extensions which cause the typical chess ram to search >>1-2 plies less deep in the typical case, although it will probe much deeper >>in the traditional sense. One other unknown is whether their 10 plies includes >>the 4 plies of hardware search. They don't count total nodes that I noticed >>anywhere, so it isn't easy to decide. For me, 1M nodes per second gives a >>depth of 13-14 in the middlegame. Going 200M should drive that to roughly >>log3(200) which is about 5 plies deeper. So call that 18-19 plies. Removing >>null-move would subtract 2, so 16-17 plies. Singular extensions 1-2 more plies, >>so that would be (14-15) to (15-16) plies. > >I am not sure this is correct. Are you saying when Crafty searches 19 plies with >nullmove R=2, it must search 17 plies without nullmove? As far as I know without >nullmove and other pruning tricks your branching factor is 4,5 and with nullmove >it is 2,5. I don't think you can simply subtract R at any depth. I'm not sure >though. It's easy to test anyway... > > >Regards, >Bas Hamstra. > I run without null-move often, when testing. It really is worth about 2 plies... At most any depth I have tested it at... > >>Somewhere on their web site they mentioned 14 plies as "normal". So their >>iteration number might be slightly different from "ours". IE when I search >>until depth is reduced to zero, I go to the quiescence search. They might >>go to their hardware, which is not exactly a "quiescence search" since it looks >>at all moves for 4 plies, but doesn't do any of the singular stuff and so forth. >> >>I'll try to ask next time I hear something from Hsu.
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