Characterization of a hybrid Monte Carlo search algorithm for structure determination

A hybrid Monte Carlo (HMC) search algorithm has recently been shown to be a promising method for structure determination from powder diffraction data [ Johnston, David, Markvardsen & Shankland ( 2002). Acta Cryst. A58, 441 - 447]. Here, the performance of the algorithm on a number of different crystal structures is investigated as a function of its control parameters. This detailed analysis required the use of a system for distributed computing in order to keep the calculation times within a reasonable time frame. The results obtained confirm previous findings and a detailed discussion of the effect of the control parameters on the efficiency of the HMC method is provided. The results suggest a method for setting these parameters automatically, which is an essential step if HMC is to find routine use in the determination of crystal structures.