Variance Function Structure

If object is a one-sided formula, it is used as the argument to varFixed and the resulting object is returned. Else, if object already inherits from class "varFunc", such as all standard ‘varClasses’, it is returned unchanged.

varFunc(object)

Arguments

object

either an one-sided formula specifying a variance covariate, or an object inheriting from class "varFunc", representing a variance function structure.

Value

an object from class "varFunc", representing a variance function structure.

Author

José Pinheiro and Douglas Bates bates@stat.wisc.edu

Examples

vf1 <- varFunc(~age)