1. A computer-implemented method of graphically presenting parameter sensitivity of a sub-circuit of a non-linear device, the method comprising: receiving a model of the sub-circuit, the model of the sub-circuit being dependent upon a plurality of model specific parameters; receiving a set of input variables to be presented, wherein said input variables are selected from the model specific parameters; receiving a simulation target set to be displayed, wherein elements of the simulation target set are derivable from response characteristics of the sub-circuit as determined by the model; and dynamically providing on a graphical user interface on a computer monitor a graphical representation of the simulation target set based upon values of said input variables.