g = rbfderiv(net, x)
g = rbfderiv(net, x) takes a network data structure net
and a matrix of input vectors x and returns a three-index matrix
g whose i, j, k element contains the
derivative of network output k with respect to weight or bias
parameter j for input pattern i. The ordering of the
weight and bias parameters is defined by rbfunpak. This
function also takes into account any mask in the network data structure.
rbf, rbfpak, rbfgrad, rbfbkpCopyright (c) Ian T Nabney (1996-9)