formula.varFunc {nlme}R Documentation

Extract varFunc Formula

Description

This method function extracts the formula associated with a varFunc object, in which covariates and grouping factors are specified.

Usage

formula(object)

Arguments

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

Value

if object has a formula attribute, its value is returned; else NULL is returned.

Author(s)

Jose Pinheiro and Douglas Bates

Examples

library(nlme)
formula(varPower(form = ~ fitted(.) | Sex))


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