Optimisation of the Ewald Sum for Large Systems

Abstract Techniques are described for optimising the Ewald sum in the simulation of systems containing large numbers of charged particles. Expressions are given for the best choice of parameters to maximise performance for a specified accuracy. The algorithm for the real-space sum uses a “small-cell” version of the link-cell method. Various other computational details are discussed. In the simulation of real systems there is considerable scope for speeding the calculation by redcing cutoffs, without loss of accuracy.