EDP Sciences
Free access
Volume 382, Number 2, February I 2002
Page(s) 758 - 767
Section Computational methods
DOI http://dx.doi.org/10.1051/0004-6361:20011609

A&A 382, 758-767 (2002)
DOI: 10.1051/0004-6361:20011609

An efficient parallel tree-code for the simulation of self-gravitating systems

P. Miocchi and R. Capuzzo-Dolcetta

Dipartimento di Fisica, Universitá di Roma "La Sapienza", P.le Aldo Moro, 5, 00185 - Rome, Italy

(Received 10 April 2001 / Accepted 5 November 2001 )

We describe a parallel version of our tree-code for the simulation of self-gravitating systems in Astrophysics. It is based on a dynamic and adaptive method for the domain decomposition, which exploits the hierarchical data arrangement used by the tree-code. It shows low computational costs for the parallelization overhead - less than 4% of the total CPU-time in the tests done - because the domain decomposition is performed "on the fly" during the tree-construction and the portion of the tree that is local to each processor "enriches" itself of remote data only when they are actually needed. The performance of an implementation of the parallel code on a Cray T3E is presented and discussed. They exhibit a very good behaviour of the speedup (=15 with 16 processors and 105 particles) and a rather low load unbalancing ( < 10% using up to 16 processors), achieving a high computation speed in the forces evaluation ( > 104 particles/sec with 8 processors).

Key words: methods: numerical -- methods: N-body simulations -- globular clusters: general

Offprint request: P. Miocchi, miocchi@uniroma1.it

© ESO 2002