|OpenAtom is a Car-Parrinello Ab-Initio Molecular Dynamics (CPAIMD) software developed by the Parallel Programing Laboratory, UIUC in collaboration with IBM, NYU, and Yale. It is a highly scalable and portable parallel application for molecular dynamics simulations at the quantum level. OpenAtom is written using the Charm++ parallel programming framework.|
OpenAtom is a parallel simulation software for studying atomic and molecular systems based on quantum chemical principles. In contrast to classical computational molecular dynamics based on Newtonian mechanics, it uses the Car-Parrinello Ab Initio Molecular Dynamics (CPAIMD) approach. Instead of using an empirical force function, the CPAIMD algorithm computes the forces acting on each atom as the summation of multiple terms derived from plane-wave density functional theory. This allows OpenAtom to study complex atomic and electronic physics in semiconductor, metallic, biological and other molecular systems.
OpenAtom is implemented on top of Charm++, which is an over-decomposition based parallel programming framework that provides support for message-driven execution of migratable entities empowered by an adaptive runtime system. Charm++ encourages decomposition of parallel computation using units that are natural to the application domain, instead of dividing data into as many pieces as processors. In particular, OpenAtom decomposes the data and the computation across a number of chare objects, whose type and/or number only depend on the CPAIMD algorithm and the desired grainsize. This allows OpenAtom to exploit the underlying mathematics via a seamless mix of both data and functional decompositions resulting in greater expressed parallelism, and several overlapping phases of computation combined with a longer critical path of dependent computations. The current implementation of OpenAtom in Charm++ is highly scalable, and has exhibited portable performance across three generations of the IBM Blue Gene family, apart from other supercomputing platforms. Look here for detailed performance results.