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MetabolAnalyze (version 1.3.1)

mstep2: Second M-step of the AECM algorithm when fitting a mixture of PPCA models.

Description

Internal function required for fitting a mixture of PPCA models.

Usage

mstep2(Y, Tau, Pi, mu, W, Sig, g, p, q)

Arguments

Y

A N x p data matrix.

Tau

An N x G matrix of posterior group membership probabilities.

Pi

A g vector of group probabilities.

mu

A p x g matrix containing the mean for each group.

W

A p x q x g array, each sheet of which contains a group specific loadings matrix.

Sig

The variance parmeter.

g

The number of groups currently being fitted.

p

The number of spectral bins in the NMR spectrum.

q

The number of principal components in the model being fitted.

Value

A list containing

W

A p x q x g array, each sheet of which contains a group specific loadings matrix.

Sig

The variance parameter.

Details

Second M-step of the AECM algorithm when fitting a mixture of PPCA models. An internal function.

References

Nyamundanda, G., Gormley, I.C. and Brennan, L. (2010) Probabilistic principal components analysis for metabolomic data. Technical report. University College Dublin, Ireland.

See Also

mppca.metabol