Parallel treeSPH

Romeel Davé, John Dubinski, Lars Hernquist

Research output: Contribution to journalArticlepeer-review

77 Scopus citations


We describe PTreeSPH, a gravity treecode combined with an SPH hydrodynamics code designed for parallel supercomputers having distributed memory. Our computational algorithm is based on the popular TreeSPH code of Hernquist & Katz (1989)[ApJS, 70, 419]. PTreeSPH utilizes a domain decomposition procedure and a synchronous hypercube communication paradigm to build self-contained subvolumes of the simulation on each processor at every timestep. Computations then proceed in a manner analogous to a serial code. We use the Message Passing Interface (MPI) communications package, making our code easily portable to a variety of parallel systems. PTreeSPH uses individual smoothing lengths and timesteps, with a communication algorithm designed to minimize exchange of information while still providing all information required to accurately perform SPH computations. We have incorporated periodic boundary conditions with forces calculated using a quadrupole Ewald summation method, and comoving integration under a variety of cosmologies. Following algorithms presented in Katz et al. (1996)[ApJS, 105, 19], we have also included radiative cooling, heating from a parameterized ionizing background, and star formation. A cosmological simulation from z = 49 to z = 2 with 643 gas particles and 643 dark matter particles requires ∼ 1800 node-hours on a Cray T3D, with a communications overhead of ∼ 8%, load balanced to ≳ 95% level. When used on the new Cray T3E, this code will be capable of performing cosmological hydrodynamical simulations down to z = 0 with ∼ 2 × 106 particles, or to z = 2 with ∼ 107 particles, in a reasonable amount of time. Even larger simulations will be practical in situations where the matter is not highly clustered or when periodic boundaries are not required.

Original languageEnglish (US)
Pages (from-to)277-297
Number of pages21
JournalNew Astronomy
Issue number3
StatePublished - Aug 1997
Externally publishedYes


  • Cosmology: theory
  • Methods: numerical

ASJC Scopus subject areas

  • Instrumentation
  • Astronomy and Astrophysics
  • Space and Planetary Science


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