Extract varFunc Covariate
DESCRIPTION:
This method function extracts the covariate(s) associated with the
variance function represented by
object
, if any is present.
USAGE:
getCovariate(object)
REQUIRED ARGUMENTS:
- object
-
an object inheriting from class
varFunc
,
representing a variance function structure.
VALUE:
if
object
has a
covariate
attribute, its value is
returned; else
NULL
is returned.
SEE ALSO:
EXAMPLES:
vf1 <- varPower(1.1, form = ~age)
covariate(vf1) <- Orthodont[["age"]]
getCovariate(vf1)