1. A neurostimulation system for use in providing therapy to a patient, comprising: a user input device configured for receiving input from a user; and processing circuitry configured for selecting an electrode configuration in response to receiving the input from the user, providing an electrical model of a neuronal element of the patient, providing a discrete approximation of a differential equation of a neural response parameter of the electrical model as a function of discrete space and as a function of a finite time difference, computing the neural response parameter in the differential equation approximation at a specified time for each of a plurality of points on a membrane of the neuronal element, and performing a human-discernible function based on the computed neural response parameters.