The purpose of this project is to develop an astrophysics and cosmology software application "Enzo-P", built on the highly scalable parallel adaptive mesh refinement (AMR) software framework "Cello" that is being developed concurrently. The Enzo-P application will be capable of running extreme scale numerical simulations to investigate frontier questions in star formation, molecular cloud turbulence, interstellar medium dynamics, galaxy formation, intergalctic medium, formation of the first stars and galaxies, galaxy clusters, and cosmic reionization. This new software will empower the current large and diverse Enzo user/developer community to take full advantage of current and future high performance computer (HPC) systems. The Cello AMR framework can be used independently of Enzo-P, thus enabling researchers in other diverse scientific fields to develop AMR applications capable of running on "Petascale-and-beyond" HPC platforms.
The novel approach used for Cello is to implement a "forest-of-octree" AMR scheme using the Charm++ parallel programming system. Octree-based AMR has been shown to be among the highest scaling AMR approaches, with demonstrated scaling to over 200K CPU cores. The Charm++ object-oriented parallel programming language supports data-driven asynchronous execution, is inherently latency-tolerant and automatically overlaps computation with communication, and provides support for developing Exascale applications, including in-memory distributed checkpointing and sophisticated dynamic load balancing schemes. Enzo-P development will be directed by the vibrant Enzo open development community, who will migrate Enzo's self-gravity, cosmology, chemistry and cooling, MHD, and radiation hydrodynamics capabilities to use the Cello scalable AMR framework.
