1. A method for operating a computational device as a support vector machine in order to define a decision surface separating two opposing classes of a training set of vectors, the method including the steps of: associating a distance parameter with each vector of the training set, the distance parameter indicating a distance from its associated vector to the opposite class; and determining a linearly independent set of support vectors from the training set such that the sum of the distances associated with the linearly independent support vectors is minimised.