an open framework for relativisitic simulations
openGR is an actively developed framework to support large numerical simulations in general relativity. Implementing techniques like constrained evolution, multiple evolved coordinate patches, mesh refinement, and robust wave extraction within a modular scalable finite-difference framework allows openGR to attack a wide range of physical problems. The openGR framework supports evolution in modular environment and currently provides evolution schemes for ADM, BSSN, and NOR formalisms.
The scalability and modularity of the framework gives developers in the general relativity community room to grow openGR to fit their needs while retaining the framework's stability and performance benefits. The finite-differencing scheme sets the groundwork for future matter simulations where smooth data is not always possible. The multiple coordinate patch infrastructure allows for a wide range of initial data, comoving patches surrounding excised regions, and increased stability for problem specific approaches to physical simulations.
For the varying array of problems which are of interest to the relativity community, openGR provides a robust and easily modified elliptic solve routine along with Kerr-schild initial data, puncture initial data, and Brill wave initial data. The initial data, and constrained ADM and NOR evolutions, are solved via the York conformal decomposition method.