/// <summary>
/// Gets the current bound for MIP.
/// If the current solution is Optimal, then Bound equals objective Value.
/// If not yet optimal, then Bound is best relaxation bound of all nodes left on the search tree.
/// This value is not available for all solvers.
/// </summary>
/// <param name="solver">The solver. Only available for OsiCbc.</param>
/// <returns>The current bound</returns>
internal static double Bound(this COIN.OsiSolverInterface solver)
{
Ensure.NotNull(solver, "solver");
if (solver.isProvenOptimal())
{
return(solver.getObjValue());
}
// not optimal, so depends per solver
if (solver is COIN.OsiCbcSolverInterface osiCbc)
{
return(osiCbc.Model.getBestPossibleObjValue());
}
throw new NotImplementedException($"Bound is not implemented for OsiSolverInterface type {solver.GetType()}");
}
/// <summary>
/// Pass this message handler to the given solver.
/// Warning: The solver will use the handler for all components. This likely has unintended consequences.
/// </summary>
/// <param name="solver">The solver to pass this message handler to.</param>
public void PassToSolver(COIN.OsiSolverInterface solver)
{
solver.passInMessageHandler(messageHandler);
}
