Large scale atomistic polymer simulations using Monte Carlo methods for parallel vector processors

In this paper we discuss the implementation of advanced variable connectivity Monte Carlo (MC) simulation methods for studying large (> 10(5) atom) polymer systems at the atomic level. Such codes are intrinsically difficult to optimize since they involve a mixture of many different elementary MC steps, such as reptation, flip, end rotation, concerted rotation and volume fluctuation moves. In particular, connectivity altering MC moves, such as the recently developed directed end bridging (DEB) algorithm, are required in order to vigorously sample the configuration space. Techniques for effective vector implementation of such moves are described. We also show how a simple domain decomposition method can provide a general and efficient means of parallelizing these complex MC protocols. Benchmarks are reported for a 192,000 atom simulation of polydisperse linear polyethylene with an average chain length C-6000, for simulations using I to 8 processors and a variety of MC protocols. (C) 2002 Elsevier Science B.V. All rights reserved.