if groups is missing, it returns the Dim attribute of
object; otherwise, calculates the dimensions associated with
the grouping factor.
Usage
"Dim"(object, groups, ...)
Arguments
object
an object inheriting from class "corStruct",
representing a correlation structure.
groups
an optional factor defining the grouping of the
observations; observations within a group are correlated and
observations in different groups are uncorrelated.
...
some methods for this generic require additional
arguments. None are used in this method.