1. A method for a real-time control of a driving factor of a complex system or process, wherein a status of the complex system or process is governed by a plurality of driving factors, Pi (i=1. .. k), varying in discretized domains where NPi is a plurality of discretization points of each driving factor Pi over its domain, comprising the steps of: obtaining a parametric model of a simulation in a form of a functional equation connecting a response to variations in the plurality of driving factors for any combination of values of the driving factors in their range of variation in a form of a sum of N modes, involving k functions of the driving factors, where each mode is defined for each of the NPi discretized values, the parametric model is identified offline by successive supplementations by invoking a weak formulation of a problem, on a super-computer, in a form of a computer program and storing the computer program in an independent device comprising: a memory to store the parametric model comprising N modes defined in all the NPi discretized values of the plurality of the driving factors; a processor configured to implement computations relating to the parametric model; an output port configured to supply proportional numeric information at an output during the implementation of the parametric model by the processor; obtaining instantaneous values of the plurality of driving factors of the system or process; executing the computer program representing the parametric model on the independent device and determining a value of a response parameter depending on the instantaneous values of the driving factors; modifying the status of the system or process by modifying the value of a driving factor on the basis of the value of the computed response parameter.