Parallel Gibbs-ensemble simulations

A truly parallel algorithm for the Gibbs-ensemble simulation technique is given. The key components of this algorithm are a parallel displacement move based on the hybrid Monte Carlo method and a parallel exchange move based on a novel algorithm. For the parallel exchange move each processor generates additional trial conformations, and a trial conformation is selected with the most favourable energy. This introduces a bias, which is removed by a modification of the acceptance rules. A proof of the correctness of the parallel exchange move is given and the algorithm is verified for a Lennard-Jones system. Simulations on ten processors of an SP/2 parallel computer give a speedup of eight for large systems and a speedup of four for systems of typical size.