A modified tree code: Don't laugh; It runs

doi:10.1016/0021-9991(90)90232-P

Journal of Computational Physics

Volume 87, Issue 1, March 1990, Pages 161-170

https://doi.org/10.1016/0021-9991(90)90232-P Get rights and content

Abstract

I describe a modification of the Barnes-Hut tree algorithm together with a series of numerical tests of this method. The basic idea is to improve the performance of the code on heavily vector-oriented machines such as the Cyber 205 by exploiting the fact that nearby particles tend to have very similar interaction lists. By building an interaction list good everywhere within a cell containing a modest number of particles and reusing this interaction list for each particle in the cell in turn, the balance of computation can be shifted from recursive descent to force summation. Instead of vectorizing tree descent, this scheme simply avoids it in favor of force summation, which is quite easy to vectorize. A welcome side-effect of this modification is that the force calculation, which now treats a larger fraction of the local interactions exactly, is significantly more accurate than the unmodified method.

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^∗: Current address: Canadian Institute for Theoretical Astrophysics, 60 Saint George Street, Toronto, Ontario, Canada M5S 1Al.

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A modified tree code: Don't laugh; It runs

Abstract

J. Comput. Phys.

J. Comput. Phys.

SIAM J. Sci. Statist. Comput.

Dynamics of Star Clusters, Princeton, New Jersey, 1984

Nature

J. Comput. Phys.