1. A method of data processing with a program-controlled processor for determining a characteristic function from a matrix with a defined number of data records having classifiable features, wherein the method comprises processing the matrix, and calculating the characteristic function based on the processed matrix, and wherein processing includes enriching the matrix with classes for the features while retaining the number of data records and compressing according to the classes with a reduction in the number of data records, and further wherein the method additionally comprises interpretating a predetermined scheme in which a sequence of the individual executions for enrichment and compression, and rules for the particular individual executions are defined.