An improved events list algorithm

Abstract

One of the basic overhead activities necessary to carry out a discrete event simulation is the insertion and deletion of event notices (transactions) in/from the event list (future events chain). The insertion of event notices is of particular interest, because it requires a search of the event list to determine the point at which an event notice should be inserted. If a linear search is used, as is the case with most simulation languages, the time consumed by the search can grow as N2, where N is the average size of the event list. In a paper entitled “A Comparison of Event List Algorithms,” authors Jean G. Vaucher and Pierre Duval (1) evaluated three algorithms as alternatives to linear search. They concluded that an “...indexed list algorithm provides the best overall performance.” This paper describes a new algorithm, based on the indexed list algorithm of Vaucher and Duval. The algorithm is adaptive to the distribution of event interarrival times. Results are shown that indicate the algorithm works well with a number of distributions and that shortcomings of the indexed list algorithms are overcome.