IllinoisGRMHD: an open-source, user-friendly GRMHD code for dynamical spacetimes

Abstract

In the extreme violence of merger and mass accretion, compact objects like black holes and neutron stars are thought to launch some of the most luminous outbursts of electromagnetic and gravitational wave energy in the Universe. Modeling these systems realistically is a central problem in theoretical astrophysics, but has proven extremely challenging, requiring the development of numerical relativity codes that solve Einstein's equations for the spacetime, coupled to the equations of general relativistic (ideal) magnetohydrodynamics (GRMHD) for the magnetized fluids. Over the past decade, the Illinois numerical relativity (ILNR) group's dynamical spacetime GRMHD code has proven itself as a robust and reliable tool for theoretical modeling of such GRMHD phenomena. However, the code was written 'by experts and for experts' of the code, with a steep learning curve that would severely hinder community adoption if it were open-sourced. Here we present IllinoisGRMHD, which is an open-source, highly extensible rewrite of the original closed-source GRMHD code of the ILNR group. Reducing the learning curve was the primary focus of this rewrite, with the goal of facilitating community involvement in the code's use and development, as well as the minimization of human effort in generating new science. IllinoisGRMHD also saves computer time, generating roundoff-precision identical output to the original code on adaptive-mesh grids, but nearly twice as fast at scales of hundreds to thousands of cores.

Additional Information

© 2015 IOP Publishing Ltd. Received 28 January 2015, revised 26 May 2015; Accepted for publication 23 June 2015; Published 10 August 2015. We gratefully acknowledge the ET community for hosting the IllinoisGRMHD software, and Sean T McWilliams for useful discussions and for generously lending time on the Spruce Knob HPC resource at WVU. This paper was supported in part by NSF Grant PHY-1300903 and NASA Grants NNX13AH44G and 13-ATP13-0077. VP is supported in part by the Simons Foundation and by NSF grant PHY-1305682. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF grant number OCI-1053575.

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Submitted - 1501.07276v2.pdf

Published - Etienne_2015.pdf

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