Title: WOMBAT: A Scalable and High Performance Astrophysical MHD Code,
Abstract: We present a new code for astrophysical magneto-hydrodynamics specifically
designed and optimized for high performance and scaling on modern and future
supercomputers. We describe a novel hybrid OpenMP/MPI programming model that
emerged from a collaboration between Cray, Inc. and the University of
Minnesota. This design utilizes MPI-RMA optimized for thread scaling, which
allows the code to run extremely efficiently at very high thread counts ideal
for the latest generation of the multi-core and many-core architectures. Such
performance characteristics are needed in the era of "exascale" computing. We
describe and demonstrate our high-performance design in detail with the intent
that it may be used as a model for other, future astrophysical codes intended
for applications demanding exceptional performance.