formula.pdMat {nlme} | R Documentation |
Extract pdMat Formula
Description
This method function extracts the formula associated with a
pdMat
object, in which the column and row names are specified.
Usage
## S3 method for class 'pdMat'
formula(x, asList, ...)
Arguments
x |
an object inheriting from class |
asList |
logical. Should the |
... |
some methods for this generic require additional arguments. None are used in this method. |
Value
if x
has a formula
attribute, its value is
returned, else NULL
is returned.
Note
Because factors may be present in formula(x)
, the
pdMat
object needs to have access to a data frame where the
variables named in the formula can be evaluated, before it can resolve
its row and column names from the formula.
Author(s)
José Pinheiro and Douglas Bates bates@stat.wisc.edu
See Also
Examples
pd1 <- pdSymm(~Sex*age)
formula(pd1)
[Package nlme version 3.1-166 Index]