getCovariate.varFunc {nlme} | R Documentation |
This method function extracts the covariate(s) associated with the
variance function represented by object
, if any is present.
getCovariate(object)
object |
an object inheriting from class varFunc ,
representing a variance function structure. |
if object
has a covariate
attribute, its value is
returned; else NULL
is returned.
Jose Pinheiro and Douglas Bates
data(Orthodont) vf1 <- varPower(1.1, form = ~age) covariate(vf1) <- Orthodont[["age"]] getCovariate(vf1)