1. A method of collecting output data from an engine, comprising: defining a set of engine inputs, by representing an input space as a grid; wherein the engine inputs represent settings of one or more engine actuators; defining a set of engine outputs; for each gridpoint, acquiring response data after fast system states have settled; representing the output quantities as a linear mathematical model; optimizing the output quantities by solving the output quantities for a minimum inequality constraint; verifying the solution; and repeating the optimizing step for a more relaxed constraint, based on the results of the verifying step.