Numerical relativity is a field of physics that uses numerical methods to solve Einstein’s equations of general relativity or other field equations governing relativistic gravity. Numerical relativity is used to model and understand astrophysical systems such as the collisions of black holes and neutron stars, the generation and dynamics of gravitational waves, supernovae explosions, and cosmological spacetimes.

The complexity of Einstein’s Equations, and the need to simulate 3D spacetimes, has meant that the numerical relativity community has needed to develop a large amount of scientific software, which is usually run of supercomputers. This has led to numerical relativity being a driver for supercomputers and modern cyberinfrastructure.

The NCSA Gravity Group develop and use the Einstein Toolkit, based on the Cactus Framework, to model black hole, neutron star and boson star binary systems, and the GAMER code for cosmological spacetimes. We are part of the NSF Blue Waters and XSEDE projects which provide computational resources and support for our work.