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From: news@sun.eng.sun.com (news)
Newsgroups: sci.nanotech
Subject: Greengard algorithm wanted
Message-ID: <Aug.31.17.37.53.1989.12166@athos.rutgers.edu>
Date: 31 Aug 89 21:37:58 GMT
Sender: nanotech@athos.rutgers.edu
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I recently ran across a book by a Dr. Greengard (MIT Press, 1988)
which describes an algorithm that calculates the n-body problem
with respect to gravitational or electrostatic fields such that
the complexity is O(n) rather than O(n^2).  It appears to use
quadtrees and fields.

I would think that if this is possible, source code would be 
available to do this...or at least an understandable description
of the algorithm (the book is rather dry).

Please send me pointers to better descriptions, third party 
analysis or best of all *shareware*/*public domain* software
that implements the Greengard algorithm.  (If you have Greengard's
email address...)

Please send me mail directly since I don't read all these newsgroups.

Thanks in advance,


Paul E. Baclaski
Sun Microsystems
peb@sun.com