1. A method for operating a digital processing apparatus including a processor for classifying music, comprising: (a) providing music classification data that are descriptive for a discrete and finite set of a finite number of music classes; (b) providing an unclassified piece of music to be classified; (c) deriving, in the processor, for each of said music classes of said set of music classes, a respective Gish distance value with respect to said unclassified piece of music to be classified to obtain a discrete and finite set of a finite number of Gish distance values, wherein said finite set of a finite number of Gish distance values is descriptive for a relation of said unclassified piece of music to be classified with respect to said discrete and finite set of a finite number of music classes.