Parallel Distributed Fast 3d Poisson Solver

The fast Poisson solvers based on FFT computations are among the fastest techniques to solve Poisson problems on uniform grids. In this report, we present two parallel distributed implementations of a 3D fast Poisson solver in the context of the atmospheric simulation code Meso-NH 2]. The rst parallel implementation consists in implementing data movement between each computational step so that no elementary computational routine implements communication. The second approach intends to reduce the global data movement and requires to parallelize one step of the fast Poisson solver algorithm. Experimental results are given on a 128 node Cray T3E to illustrate the advantages and the drawbacks of each approach.