getCovariate.corStruct         package:nlme         R Documentation

Extract corStruct Object Covariate

Description:

     This method function extracts the covariate(s) associated with
     'object'.

Usage:

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

Arguments:

  object: an object inheriting from class 'corStruct' representing a
          correlation structure.

    form: this argument is included to make the method function
          compatible with the generic. It will be assigned the value of
          'formula(object)' and should not be modified.

    data: an optional data frame in which to evaluate the variables
          defined in 'form', in case 'object' is not initialized and
          the covariate needs to be evaluated.

Value:

     when the correlation structure does not include a grouping factor,
     the returned value will be a vector or a matrix with the
     covariate(s) associated with 'object'. If a grouping factor is
     present, the returned value will be a list of vectors or matrices
     with the covariate(s) corresponding to each grouping level.

Author(s):

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

References:

     Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S
     and S-PLUS", Springer.

See Also:

     'getCovariate'

Examples:

     cs1 <- corAR1(form = ~ 1 | Subject)
     getCovariate(cs1, data = Orthodont)

