distinguish_mip_infeasible_or_unbounded

(function from pyomo.contrib.gdpopt.solve_discrete_problem)

pyomo.contrib.gdpopt.solve_discrete_problem.distinguish_mip_infeasible_or_unbounded(m, config)

Distinguish between an infeasible or unbounded solution.

Linear solvers will sometimes tell me that a problem is infeasible or unbounded during presolve, but not distinguish between the two cases. We address this by solving again with a solver option flag on.