Virial Based Berendsen Barostat on GPUs using AMOEBA in Tinker-OpenMM.

The Tinker-OpenMM package for AMOEBA molecular dynamics on GPU has long been limited to the Monte Carlo barostat due to the lack of virial calculation. In this paper, we report the calculation of the internal virial for the AMOEBA forcefield. This constitutes the first GPU implementation of a polarizable internal virial. This is followed by the implementation of the Berendsen barostat into Tinker-OpenMM as a demonstration of the capability of Tinker-OpenMM to calculate the virial with sufficient accuracy to enable pressure control. These additions enable the further improvement of Tinker-OpenMM to include a wide range of virial-based barostat algorithms.