From PPMWiki

What is PPM?

The acronym PPM stands for Parallel Particle Mesh library. PPM is a software layer between the Message Passing Interface (MPI) and codes for simulations of physical systems using hybrid particle-mesh methods. The library is developed based on a unifying formulation for the simulations of discrete and continuous systems using particles. In this formulation the well known grid-free character of the method is relaxed by the introduction of a mesh for the reinitialization of the particles, the computation of the field equations, and the discretization of differential operators.

The combined existence of meshes and particles, allows for the development of a consistent and adaptive numerical method, but it presents a challenging set of parallelization issues, such as the particle-mesh interpolation, adaptive domain decomposition, or load balancing. The PPM library solves these parallelization issues for a wide range of applications from computational science and engineering.

The PPM library runs on all single-processor and multi-processor architectures, and handles both 2D and 3D problems. The library was successfully compiled and used on Intel/Linux, Apple G5/OS X, IBM p690/AIX, NEC SX-5/SUPER-UX, and AMD Opteron/Linux.