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