Nonlinear Models

The nonlinear model represents a general optimization problem with an objective function and/or constraints over variables of various types.

This model is especially suited for use with decision variables that represent a common logic, such as subsets of choices or permutations of ordering. For example, in a traveling salesperson problem permutations of the variables representing cities can signify the order of the route being optimized and in a knapsack problem the variables representing items can be divided into subsets of packed and not packed.

The Model class encodes this model and its methods provide convenient utilities for constructing such models.