comparison toolboxes/FullBNT-1.0.7/netlab3.3/mdnerr.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function e = mdnerr(net, x, t)
+%MDNERR	Evaluate error function for Mixture Density Network.
+%
+%	Description
+%	 E = MDNERR(NET, X, T) takes a mixture density network data structure
+%	NET, a matrix X of input vectors and a matrix T of target vectors,
+%	and evaluates the error function E. The error function is the
+%	negative log likelihood of the target data under the conditional
+%	density given by the mixture model parameterised by the MLP.  Each
+%	row of X corresponds to one input vector and each row of T
+%	corresponds to one target vector.
+%
+%	See also
+%	MDN, MDNFWD, MDNGRAD
+%
+
+%	Copyright (c) Ian T Nabney (1996-2001)
+%	David J Evans (1998)
+
+% Check arguments for consistency
+errstring = consist(net, 'mdn', x, t);
+if ~isempty(errstring)
+  error(errstring);
+end
+
+% Get the output mixture models
+mixparams = mdnfwd(net, x);
+
+% Compute the probabilities of mixtures
+probs     = mdnprob(mixparams, t);
+% Compute the error
+e       = sum( -log(max(eps, sum(probs, 2))));
+