obtained by simulation more quickly, effec­ Computer simulation of dynamic systems is a topic which is growing steadily in importance tively and cheaply than by experimentation and testing of the real system. System perfor­ in the physical sciences, engineering, biology and medicine. The reasons for this trend mance can also be investigated using simula­ relate not only to the steadily increasing tion for a much wider range of conditions than can be contemplated for the real system power of computers and the rapidly falling costs of hardware, but also to the availability because of operating constraints or safety of appropriate software tools in the form of requirements. Similar factors can apply in simulation languages. Problem-oriented lan­ other fields, such as biomedical systems guages of this kind assist those who are not engineering. specialists in computational methods to trans­ System simulation, using digital computers, can relate either to models based on continu­ late a mathematical description into a simula­ tion program in a simple and straightforward ous variables or to discrete-event descriptions. fashion. They can also provide useful diag­ Continuous system simulation techniques are applied to systems described by sets of differ­ nostic information when difficulties are encountered. Therefore, a simulation lan­ ential equations and algebraic equations.