MBX 1.2: Acceleration of MBX Force Calculator for Many-Body Molecular Dynamics Employing MB-pol and MB-nrg Potentials

The MBX software provides an interface to perform molecular dynamics simulations using the MB-pol water model and other MB-nrg potential energy functions. These PEFs, developed over the last decade, combine a long-range physically-inspired baseline with short-range data-driven many-body permutationally invariant polynomials trained to electronic structure data in order to achieve near ab initio accuracy at a fraction of the cost. Recently, the performance of MBX has become a focus of its development and significant progress has been made since the release of MBX 1.0 more than a year ago. While the mathematical form of MB-pol/MB-nrg’s potential en- ergy functions means they will never be as efficient as simple pairwise additive models, improving the performance of the software implementation can significantly increase the time- and length- scales accessible to high-accuracy many-body simulations. In this paper, we present MBX 1.2 and enumerate the improvements made in MBX versions 1.1 and 1.2, highlighting performance improvements in various sections of the code and showcasing MBX 1.2’s much better capacity to take advantage of multiple cores. With MBX 1.2, we believe the scope of problems to which it is affordable to apply high-accuracy MB-nrg models such as MB-pol has significantly increased.