Parallel simulation by time segmentation: methodology and applications

In this paper we present a time parallel simulation approach and discuss conditions under which this approach is applicable. Our approach involves distributing the available processors among segments of the time horizon of the simulation. We show that under certain conditions, sample paths of the system generated by a common sequence of potential events will couple (i.e., become identical) with probability one. This property will be exploited to efficiently combine the information collected on different segments of the sample path and generate a complete valid sample path. We show that the expected coupling time of the system (i.e., the amount of time required for all the sample paths of the system to couple) is essential to the efficiency of the approach. We apply our parallel simulation approach to a class of Markovian queueing networks and investigate the efficiency of the method by providing bounds and estimates for the expected coupling times.