A model reduction procedure for high level canonical PWL functions

The canonical expression introduced previously has the degrees of freedom which are necessary to represent any PWL function defined over a compact rectangular set of arbitrary dimension, subdivided by a simplicial boundary configuration with grid step δ. However, in those cases where the domain dimension is large and the grid size is small, the number of parameters of the resulting canonical expression is, in general, very large. Accordingly, the purpose of this paper is to present a method to reduce the number of parameters of a given PWL function f, based on the use of orthonormal bases of PWL functions