1. A method for tuning an impedance matching network in a step-wise fashion, comprising: receiving during a first state of a radio frequency (RF) generator a first measured input parameter value sensed between an output of the RF generator and an input of an impedance matching network when the RF generator operates at a first parametric value and the impedance matching network has a first variable measurable factor; initializing for the first state one or more models to have the first variable measurable factor and the first parametric value, wherein the one or more models including a model of the impedance matching network; calculating for the first state a first output parameter value using the one or more models from the first measured input parameter value after the one or more models are initialized to have the first variable measurable factor and the first parametric value; computing, using the first output parameter value and the one or more models, an optimum variable measurable factor for the first state for which a combination of a reflection coefficient for the first state and a reflection coefficient for a second state at an input of the one or more models is at a minimum; calculating, using the first output parameter value and the one or more models, a first favorable parametric value for which the reflection coefficient for the first state at the input of the one or more models is at a minimum; controlling during the first state the RF generator to operate at the first favorable parametric value; and setting during the first state the impedance matching network to have a first step variable measurable factor, wherein the first step variable measurable factor is closer to the optimum variable measurable factor compared to the first variable measurable factor so that the impedance matching network is tuned in a step-wise fashion for the first state.