1. A method of analyzing a solution from a multivariable predictive controller, comprising: obtaining a solution from a multivariable predictive controller having a steady-state optimizer that results in different variable constraint statuses, wherein the solution includes controlled variables that are predicted from manipulated variables; and operating on the solution to obtain a relationship between constrained variables and unconstrained variables to determine how unconstrained variables respond to changes in constrained variables; and for each constrained variable, determining how far it can be moved until a next constraint is reached; and using the relationship between the constrained and unconstrained variables to determine an amount of change needed to move a constraint for a violated variable such that the violated variable is no longer constrained into feasibility.