formula.varFunc {nlme} | R Documentation |
This method function extracts the formula associated with a
varFunc
object, in which covariates and grouping factors are
specified.
formula(object)
object |
an object inheriting from class varFunc ,
representing a variance function structure. |
if object
has a formula
attribute, its value is
returned; else NULL
is returned.
Jose Pinheiro and Douglas Bates
library(nlme) formula(varPower(form = ~ fitted(.) | Sex))