Event manipulation for discrete simulations requiring large numbers of events

  • Authors:
  • Ernst G. Ulrich

  • Affiliations:
  • Digital Equipment Corporation, Maynard, MA

  • Venue:
  • Communications of the ACM
  • Year:
  • 1978

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Abstract

The event-manipulation system presented here consists of two major parts. The first part addresses the familiar problem of event scheduling efficiency when the number of scheduled events grows large. The second part deals with the less apparent problem of providing efficiency and flexibility as scheduled events are accessed to be executed. Additional features and problems dealt with include the proper handling of simultaneous events; that certain events must be created, scheduled, and executed at the same points in simulated time; that infinite loops caused by the concatenation of such “zero-time” events are possible and must be diagnosed; that maintaining various event counts is practical and economical; and that a capability for handling “time-displaceable” events is desirable and possible.