[comp.arch] N-Body Problem Reference

malcolm@Apple.COM (Malcolm Slaney) (01/17/89)

A few weeks ago somebody mentioned that there was a new solution to the
n-body problem that was order n (instead of n^n).  The reference given was
to a thesis by L. Greengard (sp?) called something like "The Rapid Evaluation
of Potential Fields....".  

Unfortunately the Apple Library has not been able to borrow a copy of this
thesis and they say it would cost $75 to buy a copy.  This seems a bit high to
satisfy my curiosity about the algorithm.

Can somebody point me to a more readily accessible description of this work?

Thanks.

						Malcolm Slaney
						Apple Advanced Technology
						(Cochlea and Speech Group)

mbellon@mcdurb.Urbana.Gould.COM (01/18/89)

The thesis is available from MIT press for about $30.00.

The "Rapid Evaluation of Potential Fields" by Leslie Greengard.

I don't remember the ID #.

A parallel version of this is available from someone at Yale for the
Connection Machine.

The O(n log n) algorithm, which is considerably simpler than the O(n)
algorithm above, can be found in Nature #324, 4 Dec. 1986, by P. Hut and
J. Barnes. I have a complete package for using this method.

The O(n) method has a significant amountof overhead. It breaks even with the
O(n log n) method in the low thousands or so.

mbellon@xenurus.gould.com

jeffa@hpmwtd.HP.COM (Jeff Aguilera) (01/19/89)

"The Rapid Evaluation of Potential Fields in Particle Systems,"
Leslie F. Greengard, 1988, 110 pp 
1987 ACM Distinguished Dissertation
ISBN ??? 07110-X GREPH
$25.00