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(x, ...)
x |
an object inheriting from class varFunc ,
representing a variance function structure. |
... |
some methods for this generic require additional arguments. None are used in this method. |
if x
has a formula
attribute, its value is
returned; else NULL
is returned.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
formula(varPower(form = ~ fitted(.) | Sex))