MUSCLE-HPC: A new high performance API to couple multiscale parallel applications

Multiscale, multi-physics applications are central to solve the increasing number of important scientific challenges. Computationally speaking, the difficulty is to combine high performance computing with the need to couple various codes or solvers, each representing a different scale or a different physical process. In this paper, we present MUSCLE-HPC a new HPC implementation of MUSCLE-2, a previously developed Multiscale Coupling Library and Environment. We present its design and implementation and we demonstrate its advantages compared to MUSCLE-2. We conduct a performance comparison through a tightly coupled MPI application use-case. Our results indicate that using MUSCLE-HPC to couple submodels within the same HPC cluster can lead to better computing performance comparable to a native MPI execution and can, thus, reduce the coupling overhead.