TABLE OF CONTENTS Computer simulations of real systems require a model of that reality. A model consists of both a representation of the system and a set of rules that describe the behavior of the system. For dynamical descriptions one needs in addition a specification of the initial state of the system, and if the response to external influences is required, a specification of the external influences.
Both the model and the method of solution depend on the purpose of the simulation: they should be accurate and efficient. The model should be chosen accordingly. For example, an accurate quantum-mechanical description of the behavior of a many-particle system is not efficient for studying the flow of air around a moving wing; on the other hand, the Navier Stokes equations efficient for fluid motion cannot give an accurate description of the chemical reaction in an explosion motor. Accurate means that the simulation will reliably (within a required accuracy)...
