"First applications with a new performance-portable version of Athena++"

 

The installation of several exascale computing systems this year has enabled new applications in computational astrophysical fluid dynamics that were previously intractable.  However, to exploit such systems the underlying application software must be able to run efficiently on heterogeneous architectures such as GPU clusters. I will describe a re-write of the Athena++ adaptive mesh refinement code using the Kokkos library that enables applications on virtually any hardware (including CPUs, GPUs, and ARM processors).  I will then describe some of the first applications of this new code, including a study of accretion onto the central black hole in elliptical galaxies such as M87 from kiloparsec down to near horizon scales.  Additionally, new general relativisitic MHD models of black hole accretion flows in luminous systems, including full radiation transport based on direct solution of the transfer equation will be described.  Future applications and extensions of the code will be discussed.