Up to this point, we have primarily been concerned with self­-contained models, which are solved once and don’t receive input from, nor pass output to, other models.  However, in many modeling situations, there may be requirements for one, or more, models to be run in a sequence.  Furthermore, the outputs of one model may be required as inputs to a subsequent model.  Such a series of models will typically be run in a loop until some termination criterion is met.  LINGO provides a number of programming control structures to automate processing in situations where one has multiple, dependent models that one must run in a sequence.

In the section immediately following, we will provide a brief introduction to the programming features available in LINGO.  We will then illustrate the use of these features in several models.