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Subject: Re: Have You looked at Deep Blue logs?!

Author: Robert Hyatt

Date: 06:32:40 01/17/00

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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.

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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