| formula.pdMat {nlme} | R Documentation |
This method function extracts the formula associated with a
pdMat object, in which the column and row names are specified.
## S3 method for class 'pdMat': formula(x, asList, ...)
x |
an object inheriting from class pdMat, representing
a positive definite matrix. |
asList |
logical. Should the asList argument be applied to each of the components? Never used. |
... |
some methods for this generic require additional arguments. None are used in this method. |
if x has a formula attribute, its value is
returned, else NULL is returned.
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.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
pd1 <- pdSymm(~Sex*age) formula(pd1)