

   CCoonnttrrooll VVaalluueess ffoorr ggllss FFiitt

        glsControl(maxIter, msMaxIter, tolerance, msTol, msScale, msVerbose,
                   singular.ok, qrTol, returnObject, apVar, .relStep)

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

    maxIter: maximum number of iterations for the `gls' opti-
             mization algorithm. Default is 50.

   msMaxIter: maximum number of iterations for the `ms' opti-
             mization step inside the `gls' optimization.
             Default is 50.

   tolerance: tolerance for the convergence criterion in the
             `gls' algorithm. Default is 1e-6.

      msTol: tolerance for the convergence criterion in `ms',
             passed as the `rel.tolerance' argument to the
             function (see documentation on `ms'). Default is
             1e-7.

    msScale: scale function passed as the `scale' argument to
             the `ms' function (see documentation on that func-
             tion). Default is `lmeScale'.

   msVerbose: a logical value passed as the `trace' argument to
             `ms' (see documentation on that function). Default
             is `FALSE'.

   singular.ok: a logical value indicating whether non-
             estimable coefficients (resulting from linear
             dependencies among the columns of the regression
             matrix) should be allowed. Default is `FALSE'.

      qrTol: a tolerance for detecting linear dependencies
             among the columns of the regression matrix in its
             QR decomposition. Default is `.Machine$sin-
             gle.eps'.

   returnObject: a logical value indicating whether the fitted
             object should be returned when the maximum number
             of iterations is reached without convergence of
             the algorithm. Default is `FALSE'.

      apVar: a logical value indicating whether the approximate
             covariance matrix of the variance-covariance
             parameters should be calculated. Default is
             `TRUE'.

   .relStep: relative step for numerical derivatives calcula-
             tions. Default is `.Machine$double.eps^(1/3)'.

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

        The values supplied in the function call replace the
        defaults and a list with all possible arguments is
        returned. The returned list is used as the `control'
        argument to the `gls' function.

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

        a list with components for each of the possible argu-
        ments.

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

        Jose Pinheiro and Douglas Bates

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

        `gls', `ms', `lmeScale'

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

        # decrease the maximum number iterations in the ms call and
        # request that information on the evolution of the ms iterations be printed
        glsControl(msMaxIter = 20, msVerbose = TRUE)

