Convert pdBand Object to Natural Parameterization

DESCRIPTION:

This method function converts object to a pdBandNat object, represented in a natural parameterization. If unconstrained = TRUE , an unconstrained parameterization based on the logarithm of the standard deviations and the logit of the correlations (log((1+r)/(1-r)), with r denoting the correlation) is used. If unconstrained is set to FALSE, the variances and covariances are used to parameterize the returned pdBandNat object.

USAGE:

asNatural(object, unconstrained) 

REQUIRED ARGUMENTS:

object
an object inheriting from class pdBand, representing a banded positive-definite matrix, whose representation is to be converted to a natural parameterization.

OPTIONAL ARGUMENTS:

unconstrained
an optional logical value indicating whether the natural parameterization should be unconstrained. Defaults to TRUE.

VALUE:

an object of class pdBandNat representing a banded positive-definite matrix in natural parameterization.

SEE ALSO:

, ,

EXAMPLES:

pd1 <- pdBand(diag(1:3), form = ~age + age^2, data = Orthodont) 
asNatural(pd1)