GR-Athena++: Puncture evolutions on vertexcentered oct-tree AMR and compact finite differencing

ABSTRACT: GR-Athena++ is a general-relativistic, high-order, vertex-centered solver that extends the oct-tree, adaptive mesh refinement capabilities of Athena++. Dynamical spacetimes are simulated using the Z4c formulation of numerical relativity coupled to the moving puncture gauge. Robust and accurate binary black hole (BBH) mergers are demonstrated.

GR-Athena++ leverages the task-based parallelism paradigm of Athena++ to achieve excellent scalability. Strong scaling efficiencies above 95% for up to 1.2×1e4 CPUs and excellent weak scaling up to 1e5 CPUs are measured for production BBH runs. GR-Athena++ provides infrastructure for the robust simulation of compact binary coalescences and offers a viable path towards numerical relativity at exascale.

In this talk, a general overview of features outlined above will be provided. Recent developments will also be discussed together with our incorporation of compact finite differencing for vacuumsector evolution.