Characterising complexity by the degrees of freedom in a radial basis function network

Abstract In this paper we discuss an approach for characterising the complexity of a radial basis function network by estimating its effective degrees of freedom. We introduce a simple method for determining the degrees of freedom by exploiting a relationship to the theory of linear smoothers. Specifically, the complexity of the model is demonstrated theoretically and empirically to be determined by a spectral analysis of the space spanned by the outputs of the hidden layer.