pdMat Object Coefficients

DESCRIPTION:

This method function extracts the coefficients associated with the positive-definite matrix represented by object.

USAGE:

coef(object, unconstrained) 
coef(object) <- value 

REQUIRED ARGUMENTS:

object
an object inheriting from class pdMat, representing a positive-definite matrix.

OPTIONAL ARGUMENTS:

unconstrained
a logical value. If TRUE the coefficients are returned in unconstrained form (the same used in the optimization algorithm). If FALSE the upper triangular elements of the positive-definite matrix represented by object are returned. Defaults to TRUE.
value
a vector with the replacement values for the coefficients associated with object. It must be a vector with the same length of `coef{object}' and must be given in unconstrained form.

VALUE:

a vector with the coefficients corresponding to object.

SIDE EFFECTS::

On the left side of an assignment, sets the values of the coefficients of object to value.

REFERENCES:

Pinheiro, J.C. and Bates., D.M. (1996) "Unconstrained Parametrizations for Variance-Covariance Matrices", Statistics and Computing, 6, 289-296.

SEE ALSO:

EXAMPLES:

coef(pdSymm(diag(3)))