A load-balancing force decomposition scheme for parallel simulation of chemical dynamics with multiple inter-atomic force models

Force evaluation is the most computationally intensive part in a chemical dynamics simulation, and hence most parallel simulation algorithms choose the force calculation as the main target for parallelization. The majority of existing parallel algorithms assume a uniform force-evaluation cost for all atom pairs. For dynamics with considerable bonded interactions, different evaluation formulas are usually used for forces between different atom pairs, and this complicates the load balancing for the simulation of chemical dynamics on parallel computers. In this paper, we present a load-balancing scheme that takes into account differences of inter-atomic force models for different atom pairs. By considering different force models, the load partitioning of our algorithm can effectively handle the differences in computation costs for calculating different inter-atomic interactions when atom-tailored force models are used for different atom pairs, which is usually the case for bonded interactions. A parallel simulation algorithm for bonded-interaction-dominated dynamics was developed that employs the load partitioning scheme, and the algorithm was implemented and tested on different ensembles of atoms, and produced good performances for the testing problems.