function g = netgrad(w, net, x, t)%NETGRAD Evaluate network error gradient for generic optimizers%%	Description%%	G = NETGRAD(W, NET, X, T) takes a weight vector W and a network data%	structure NET, together with the matrix X of input vectors and the%	matrix T of target vectors, and returns the gradient of the error%	function evaluated at W.%%	See also%	MLP, NETERR, NETOPT%%	Copyright (c) Ian T Nabney (1996-2001)gradstr = [net.type, 'grad'];net = netunpak(net, w);g = feval(gradstr, net, x, t);