Title: Alternative fix rigid for small particles

Presenter: Trung Nguyen

Affiliation: Oak Ridge National Laboratory

Abstract: We report an alternative implementation of rigid body time integration for LAMMPS, targeting a broad class of modeling applications including liquid crystal molecules, nanoparticles, colloids and patchy particles, where the rigid body dimension is shorter than, or comparable to, the interaction range. Using a local communication scheme for summing body forces and torques, our implementation can yield a speedup up to 10-50x compared to the regular fix rigid for systems of consisting of multi-million particles across hundreds of compute nodes. We also compare the performance of this implementation with fix rigid/small, a recently released capability for similar systems, and discuss their differences.