Efficient Data Redistribution Methods for Coupled Parallel Particle Codes

This article investigates two particle data redistribution methods for the coupling of application-independent solvers for long range interactions with a particle dynamics simulation. The solvers rely on their own particle data processing techniques and domain decomposition schemes, but are implemented within a single parallel software library with a unique interface. Thus, efficient data reordering and redistribution methods are required for the data transfer between an application and the library interface as well as between the library interface and a solver. The first particle data redistribution method hides all data reordering and redistribution inside the library and restores the original particle order and distribution. The second method uses the solver-specific particle order and distribution for the particle dynamics simulation to reduce the communication amount of particle redistribution steps. Both methods and their effects on the different program components of a parallel particle code are described. Performance results on the parallel computing cluster JuRoPA and the IBM Blue Gene/Q system Juqueen are presented to demonstrate the performance improvements achieved within a particle dynamics simulation application.