General Correlation in Natural Parameterization

DESCRIPTION:

This method function converts object to a corSymmNat object, represented in a natural parameterization. If unconstrained = TRUE , an unconstrained parameterization based on the logit of the correlations (log((1+r)/(1-r)), with r denoting the correlation) is used. If unconstrained is set to FALSE, the (constrained) correlations are used to parameterize the returned corSymmNat object. This corStruct class does not define an unrestricted parameterization and, thus, should NOT be used for optimization. It is mostly used for deriving approximate confidence intervals on parameters following the optimization of an objective function.

USAGE:

corSymmNat(object, unconstrained) 

REQUIRED ARGUMENTS:

object
an object inheriting from class corSymm, representing a general correlation structure, 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 corSymmNat representing a general correlation structure in natural parameterization.

SEE ALSO:

,

EXAMPLES:

cst1 <- corSymm(form = ~1|Subject) 
cst1 <- initialize(cst1, data = Orthodont) 
corSymmNat(cst1)