Poseidon : An Relativistic Gravity Solver for Core Collapse Supernova Simulations

The Poseidon code is designed to solve the system of equations for the general relativistic metric in the eXtended Conformally Flat Condition (XCFC) formulation of the Einstein equations.  The code is based on a discretization of the system of equations on a spherical polar grid, using a mixed spectral--finite-element method consisting of an angular decomposition in spherical harmonics and a radial expansion in Lagrange polynomials.  The non-linear algebraic equations are then solved iteratively using a fixed-point method with Anderson acceleration.Poseidon has been developed for use in core collapse supernova simulations, as part of the toolkit for high-order neutrino-radiation hydrodynamics (thornado) development.  It has been designed to operate on distributed and shared memory systems using MPI and OpenMP, respectively, and within the AMReX framework for block-structured adaptive mesh refinement. Results will be presented showing the accuracy of Poseidon’s treatment of the XCFC system, performance on distributed and shared memory systems, use within the AMReX framework, and the successful coupling to thornado's general relativistic hydrodynamics module.