Initialize varFunc Object

DESCRIPTION:

This method initializes object by evaluating its associated covariate(s) and grouping factor, if any is present, in data; determining if the covariate(s) need to be updated when the values of the coefficients associated with object change; initializing the log-likelihood and the weights associated with object ; and assigning initial values for the coefficients in object , if none were present. The covariate(s) will only be initialized if no update is needed when coef(object) changes.

USAGE:

initialize(object, data, ...) 

REQUIRED ARGUMENTS:

object
an object inheriting from class varFunc, representing a variance function structure.
data
a data frame in which to evaluate the variables named in formula(object).

OPTIONAL ARGUMENTS:

...
this argument is included to make this method compatible with the generic.

VALUE:

an initialized object with the same class as object representing a variance function structure.

SEE ALSO:

,

EXAMPLES:

vf1 <- varPower(form = ~ age | Sex) 
vf1 <- initialize(vf1, Orthodont)