pdMatrix.reStruct            package:nlme            R Documentation

Extract Matrix or Square-Root Factor from Components of an
reStruct Object

Description:

     This method function extracts the positive-definite  matrices
     corresponding to the 'pdMat' elements of 'object', or square-root
     factors of the positive-definite matrices.

Usage:

     ## S3 method for class 'reStruct':
     pdMatrix(object, factor)

Arguments:

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

  factor: an optional logical value. If 'TRUE', square-root factors of
          the positive-definite matrices represented by the elements of
          'object' are returned; else, if 'FALSE', the
          positive-definite matrices are returned. Defaults to 'FALSE'.

Value:

     a list with components given by the positive-definite matrices
     corresponding to the elements of 'object', or square-root factors
     of the positive-definite matrices.

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, esp. p. 162.

See Also:

     'as.matrix.reStruct', 'reStruct', 'pdMat',  'pdMatrix', 
     'pdMatrix.pdMat'

Examples:

     rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont))
     pdMatrix(rs1)

