Extending the accuracy, size, and duration of atomistic simulations on exascale hardware*

Because of its unparalleled predictive power, molecular dynamics (MD) has established itself as a workhorse of computational materials science. However, the limited strong-scalability of conventional MD combined with the exponential increase in parallelism currently leaves wide swaths of the theoretically-accessible simulation space inaccessible in practice, by only allowing for the simulation of larger systems but not of longer times. Fulfilling the promises of the exascale era will therefore require exposing new levels of parallelism in order to make the whole Accuracy/Size/Time simulation space accessible. The EXAALT project aims at addressing this challenge for systems that evolve through sequences of rare, thermally activated, events. By combining conventional domain decomposition with replication, speculation, and localization approaches, we show that novel computational techniques deployed at the exascale have the potential to dramatically extend the simulation space that will be accessible to MD over the next decade.