Initialize.reStruct           package:nlme           R Documentation

Initialize reStruct Object

Description:

     Initial estimates for the parameters in the 'pdMat' objects
     forming 'object', which have not yet been initialized, are
     obtained using the methodology described in Bates and Pinheiro
     (1998). These estimates may be refined using a series of EM
     iterations, as described in Bates and Pinheiro (1998). The number
     of EM iterations to be used is defined in 'control'.

Usage:

     ## S3 method for class 'reStruct':
     Initialize(object, data, conLin, control, ...)

Arguments:

  object: an object inheriting from class 'reStruct', representing a
          random effects structure and consisting of a list of 'pdMat'
          objects.

    data: a data frame in which to evaluate the variables defined in
          'formula(object)'.

  conLin: a condensed linear model object, consisting of a list with
          components '"Xy"', corresponding to a regression matrix ('X')
          combined with a response vector ('y'), and '"logLik"',
          corresponding to the log-likelihood of the underlying model.

 control: an optional list with a single component 'niterEM'
          controlling the number of iterations for the EM algorithm
          used to refine initial parameter estimates. It is given as a
          list for compatibility with other 'Initialize' methods.
          Defaults to 'list(niterEM = 20)'.

     ...: some methods for this generic require additional arguments. 
          None are used in this method.

Value:

     an 'reStruct' object similar to 'object', but with all 'pdMat'
     components initialized.

Author(s):

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

References:

     Bates, D.M. and Pinheiro, J.C. (1998) "Computational methods for
     multilevel models" available in PostScript or PDF formats at
     http://franz.stat.wisc.edu/pub/NLME/

See Also:

     'reStruct', 'pdMat'

