1. A method for controlling the output of a gas discharge laser comprising the steps of: establishing a multidimensional variable state space comprising a coordinate system having at least two coordinates, each coordinate comprising a selected variable representing an operating or output parameter of the gas discharge laser; tracking a multidimensional operating point in the multidimensional variable state space according to the variation of the selected variables in the gas discharge laser to determine the position of the multidimensional operating point in the multidimensional state space; determining from the position of the multidimensional operating point in the multidimensional operating space a region from a plurality of defined regions in the multidimensional operating space in which the multidimensional operating point is located and identifying the region; based upon the identity of the identified region, and parameters of that region relative to the condition of an actuator in the gas discharge laser, determining a necessary modification to the actuator for the gas discharge laser to attempt to move the multidimensional operating point from the parameters indicated by the position of the multidimensional operating point being in the particular region to a preselected location in the coordinate system.