formula.pdBlocked            package:nlme            R Documentation

Extract pdBlocked Formula

Description:

     The 'formula' attributes of the 'pdMat' elements of 'x' are
     extracted and returned as a list, in case 'asList=TRUE', or
     converted to a single one-sided formula when 'asList=FALSE'. If
     the 'pdMat' elements do not have a 'formula' attribute, a 'NULL'
     value is returned.

Usage:

     ## S3 method for class 'pdBlocked':
     formula(x, asList, ...)

Arguments:

       x: an object inheriting from class 'pdBlocked', representing a
          positive definite block diagonal matrix.

  asList: an optional logical value. If 'TRUE', a list with the
          formulas for the individual block diagonal elements of 'x' is
          returned; else, if 'FALSE', a one-sided formula combining all
          individual formulas is returned. Defaults to 'FALSE'.

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

Value:

     a list of one-sided formulas, or a single one-sided formula, or
     'NULL'.

Author(s):

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

See Also:

     'pdBlocked', 'pdMat'

Examples:

     pd1 <- pdBlocked(list(~ age, ~ Sex - 1))
     formula(pd1)
     formula(pd1, asList = TRUE)

