We have developed a gravity solver based on combining the particle-mesh (PM) method and TREE methods. It is designed for and has been implemented on parallel computer architectures. The new code can deal with tens of millions of particles on current computers, with the calculation done on a parallel super- computer or a group of workstations. Typically, the spatial resolution is enhanced by more than a factor of 20 over the pure PM code with mass resolution retained at nearly the PM level. This code runs much faster than a pure TREE code with the same number of particles and maintains almost the same resolution in high-density regions. Multiple time step integration has also been implemented with the code, with second-order time accuracy.The performance of the code has been checked in several kinds of parallel computer configurations, including IBM SP1, SGI Challenge, and a group of workstations, with the speedup of the parallel code on a 32 processor IBM SP2 supercomputer nearly linear (efficiency ≍ 80%) in the number of processors. The computation/communication ratio is also very high (∼50), which means the code spends 95% of its CPU time in computation.
The Astrophysical Journal Supplement Series
- Pub Date:
- May 1995
- METHODS: NUMERICAL;
- 21 Pages Latex file Figures available from anonymous ftp to astro.princeton.edu under /xu/tpm.ps, POP-579