An Efficient Parallel Implementation of Multirate Schemes for Ocean Modeling

Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by stability limits. In particular, unstructured meshes can lead to a very restrictive global stable time step. Multirate methods offer a way to increase the efficiency by gathering grid cells in appropriate groups. The parallelization of these schemes is challenging because grid cells have different workloads. We propose a strategy that shares the workload almost equitably between all processors at every multirate stage. Performance analyses are provided for ocean modeling applications