Extract varFunc Covariate

getCovariate.varFunc {nlme}

R Documentation

This method function extracts the covariate(s) associated with the variance function represented by object, if any is present.

## S3 method for class 'varFunc'
getCovariate(object, form, data)

`object`	an object inheriting from class `varFunc`, representing a variance function structure.
`form`	an optional formula specifying the covariate to be evaluated in `object`. Defaults to `formula(object)`.
`data`	some methods for this generic require a `data` object. Not used in this method.

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

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

vf1 <- varPower(1.1, form = ~age)
covariate(vf1) <- Orthodont[["age"]]
getCovariate(vf1)

[Package nlme version 3.1-139 Index]