Towards optimal parallel PM N-body codes: PMFAST

The current release version uses two grid levels on a slab decomposition, with periodic boundary conditions for cosmological applications. Open boundary conditions could be added with little computational overhead. We present timing information and results from a recent cosmological production run of the code using a 37123 mesh with 6.4 × 109 particles. PMFAST is cost-effective, memory-efficient, and is publicly available.