mdnfwd

Purpose

Forward propagation through Mixture Density Network.

Synopsis

mixparams = mdnfwd(net, x)
[mixparams, y, z] = mdnfwd(net, x)
[mixparams, y, z, a] = mdnfwd(net, x)

Description

mixparams = mdnfwd(net, x) takes a mixture density network data structure net and a matrix x of input vectors, and forward propagates the inputs through the network to generate a structure mixparams which contains the parameters of several mixture models. Each row of x represents one input vector and the corresponding row of the matrices in mixparams represents the parameters of a mixture model for the conditional probability of target vectors given the input vector. This is not represented as an array of gmm structures to improve the efficiency of MDN training.

The fields in mixparams are


  type = 'mdnmixes'
  ncentres = number of mixture components
  dimtarget = dimension of target space
  mixcoeffs = mixing coefficients
  centres = means of Gaussians: stored as one row per pattern
  covars = covariances of Gaussians
  nparams = number of parameters

[mixparams, y, z] = mdnfwd(net, x) also generates a matrix y of the outputs of the MLP and a matrix z of the hidden unit activations where each row corresponds to one pattern.

[mixparams, y, z, a] = mlpfwd(net, x) also returns a matrix a giving the summed inputs to each output unit, where each row corresponds to one pattern.

See Also

mdn, mdn2gmm, mdnerr, mdngrad, mlpfwd
Pages: Index

Copyright (c) Ian T Nabney (1996-9)

David J Evans (1998)