Lazy Queue: A new approach to implementing the Pending-event Set

In discrete event simulation, very often the future event set is represented by a priority queue. The data structure used to implement the queue and the way operations are performed on it are often crucial to the execution time of a simulation. In this paper a new priority queue implementation strategy, the Lazy Queue, is presented. It is tailored to handle operations on the pending event set efficiently. The Lazy Queue is a kind of multi-list data structure that delays the sorting process until a point near the time where the elements are to be dequeued. In this way, the time needed to sort new elements in the queue is reduced. We have performed several experiments comparing queue access times with the access times of the implicit heap and the calendar queue. Our experimental results indicate that the Lazy Queue is superior to these priority queue implementations.