NWChemEx – Computational Chemistry for the Exascale Era*

NWChemEx is an ECP project for computational chemistry that builds on the success of NWChem. NWChem is an early co-design project started in 1992, to address distributed memory parallel computers. The code's modular design, the Global Arrays for distributed data handling, and code generation using the Tensor Contraction Engine, provided a platform for building scalable chemistry capabilities. Key capabilities of the code are MD, DFT methods, and coupled cluster.
The science challenges targeted by the NWChemEx are accurate simulations of catalytic reactions and biomolecular complexes. Such calculations require next generation computers that are very different from those NWChem was designed for. Hence, NWChemEx re-engineered the concepts, models and implementations for future computers. We focus on overcoming the limitations of NWChem’s design. This involves platform enhancements like execution schedule aware tensor frameworks, composable simulations, code generation for accelerator hardware, and exploiting emerging sparsity. The required changes in the key methods will be discussed.