1. A computer program operable in response to an input of a set of N points to measure symmetry among said points, so as to determine positional entropy of said set of N points, said program comprising the steps of: receiving coordinates for each of said N points; calculating a set of a maximum of N(N−1)/2 pairs of distances within said points; calculating local symmetry; calculating global symmetry to determine a set of occupation numbers; determining from said occupation numbers a total symmetry and un-normalized positional entropy deficit; and determining a positional entropy value of said set of N points.