N-Body Simulation in C with MPI and OpenMP
Published:
The \(N\)-body problem is a classic problem in which \(N\) discrete bodies mutually interact in a dynamical system consisting of positions, forces, and velocities. A parallel algorithm for simulating the evolution of this dynamical system was implemented using C and MPI. Simulations were conducted for 100 timesteps, the number of discrete bodies was \(N \in {512,1024,4096,10000}\), and the number of MPI processes was between 2 and 128. All experiments were conducted using the Vrije Universiteit’s DAS-5 cluster’s ASUS nodes with Intel E5-2630v3 CPUs. As a bonus optimization, OpenMP was added to the MPI implementation. For 4 processes with \(N=10000\), the speedup and efficiency for the pure MPI program were \(2.31\) and \(57.64\%\), respectively. For MPI+OpenMP (aka Hybrid MPI) on the same problem the speedup and efficiency were \(7.80\) and \(194.95\%\), respectively.