varFunc                 package:nlme                 R Documentation

Variance Function Structure

Description:

     If 'object' is a one-sided formula, it is used as the argument to
     'varFixed' and the resulting object is returned. Else, if 'object'
     inherits from class 'varFunc', it is returned unchanged.

Usage:

     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(s):

     Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates
     bates@stat.wisc.edu

See Also:

     'summary.varFunc', 'varFixed', 'varWeights.varFunc',
     'coef.varFunc'

Examples:

     vf1 <- varFunc(~age)

