

   GGeenneerraalliizzeedd LLeeaasstt SSqquuaarreess SSttrruuccttuurree

        glsStruct(corStruct, varStruct)

   AArrgguummeennttss::

   corStruct: an optional `corStruct' object, representing a
             correlation structure. Default is `NULL'.

   varStruct: an optional `varFunc' object, representing a
             variance function structure. Default is `NULL'.

   DDeessccrriippttiioonn::

        A generalized least squares structure is a list of
        model components representing different sets of parame-
        ters in the linear model. A `glsStruct'  may contain
        `corStruct' and `varFunc' objects. `NULL' arguments are
        not included in the `glsStruct' list.

   VVaalluuee::

        a list of model variance-covariance components deter-
        mining the parameters to be estimated for the associ-
        ated linear model.

   AAuutthhoorr((ss))::

        Jose Pinheiro and Douglas Bates

   SSeeee AAllssoo::

        `gls', `corStruct', `varFunc'

   EExxaammpplleess::

        library(lme)
        gls1 <- glsStruct(corAR1(), varPower())

