Tabulated equations of state with a many-tasking execution model

Abstract—The addition of nuclear and neutrino physics to general relativistic fluid codes allows for a more realistic description of hot nuclear matter in neutron star and black hole systems. This additional microphysics requires that each processor have access to large tables of data, such as equations of state, and in large simulations, the memory required to store these tables locally can become excessive unless an alternative execution model is used. In this work we present relativistic fluid evolutions of a neutron star obtained using a message driven multi-threaded execution model known as ParalleX. The goal of this work is to reduce the negative performance impact of distributing the tables. We introduce a component based on the notion of a “future”, or nonblocking encapsulated delayed computation, for accessing large tables of data, including outof-core sized tables. The proposed technique does not impose substantial memory overhead and can hide increased network latency. Keywords-Astrophysics applications, ParalleX, HPX, Futures I