The ten-year challenge problem addressed by this exascale applications project is to create foundational simulations for constructing virtual universes at the extreme fidelities demanded by future multi-wavelength sky surveys. We will address this exascale challenge problem by employing a comprehensive program using the HACC and Nyx codes, suitably extended for efficient utilization of exascale resources.
The extreme-scale framework HACC is the first production science code to achieve 10 petaflops of sustained performance. It is designed for high performance, scalability, and the ability to run on all supercomputing platforms. Even with algorithmic improvements and other advances, two orders of magnitude gains in performance and increases in memory size will be required to address the challenge problem on exascale timescales. The Eulerian AMR code Nyx will complement the Lagrangian nature of HACC.
The two codes will be used to develop a joint program for verification of gravitational evolution, gasdynamics, and subgrid models in cosmological simulations at very high dynamic range.