Perspectives for efficient simulations of long range interactions with multi-billion particles.
Ivo Kabadshow Research Center Julich, Germany
The simulation of pairwise interactions in huge particle ensembles is a vital issue in scientific research. Especially the calculation of long-range interactions poses limitations to the system size, since these interactions scale quadratically with the number of particles. This talk is divided into two parts. First I will present the open source ScaFaCoS library. The purpose of the framework is to provide a unified parallel library for various methods including the fast multipole method, the Barnes-Hut tree method, particle-mesh Ewald methods or multigrid methods to solve electrostatic and gravitational problems in large particle simulations. In the second part I will highlight one specific method of the library, namely the FMM. We improved the fast summation algorithm by adding a tight error control scheme and on-the-fly runtime minimization. The current code also benefits from a reduced memory footprint and is therefore capable of computing all pairwise interactions for systems with open, 1D, 2D and 3D periodic boundaries on 300k BG/P cores with up to three trillion particles. To achieve strong parallel scaling, the code employs a one-sided, non-blocking parallelization scheme with small communication overhead.
CECAM - Centre Européen de Calcul Atomique et Moléculaire Ecole Polytechnique Fédérale de Lausanne, Batochime (BCH), 1015 Lausanne, Switzerland