Understanding Model- and Solution-Status

This section describes the relation between SolutionStatus and ModelStatus, which are both set for a Solution after the respective Model has been solved. The status depend on the structure of the solved Model (e.g. infeasible, unbounded) and on the optimization process (e.g. interrupted by user, timeout). Furthermore, some of the resulting Solution's properties may still be null, e.g. in case of an infeasible or unbounded Model.

Case: Model solved to optimality

The Model has been solved to optimality for all objectives / objective stages. The VariableValues and ObjectiveValues Properties are be initialized with the respective solution values. The Status is set to Optimal and the ModelStatus to Feasible.

Case: Model is infeasible or unbounded

In this case, the Solver cannot compute a solution, and thus no Variable values are returned. The VariableValues and ObjectiveValues are null. Gap will return @OPTANO.Modeling.Optimization.double.NaN. The Status is NoSolutionValues. Dependent on the reason that caused the Model to not be feasible, ModelStatus either is Infeasible, Unbounded, or InfOrUnbd.

Case: Model is not solved to optimality

This case can occur if the User has set further limitations, such as a time limit, an iteration limit, a node limit, or simply interrupted the solution process.

Feasible Solution has already been found

If the solver already found a feasible solution for the Model, the Status is set to Feasible. All other Solution properties behave just as in the optimal case.

No Solution found

If the solver did not find a feasible Solution, the Status is set to NoSolutionValues and the ModelStatus to Unknown. All other Solution process behave as in the infeasible case.