Solution Status Codes

This table lists the statuses for solutions to LP, QP, or MIP problems. These values are returned by the routine CPXgetstat() or by the member functions IloCplex::getCplexStatus() and IloCplex::getCplexSubStatus(). If no solution exists, the return value is zero.

The treatment of models that are Unbounded involves a few subtleties. Specifically, a declaration of unboundedness means that CPLEX has determined that the model has an unbounded ray. Given any feasible solution x with objective z, a multiple of the unbounded ray can be added into x to give a feasible solution with objective z-1 (or z+1 for maximization models). Thus, if a feasible solution exists, then the optimal objective is unbounded. Note that CPLEX has not necessarily concluded that a feasible solution exists. Users can call function CPXsolninfo() to determine whether CPLEX has also concluded that the model has a feasible solution.