If present, the grouping formula associated with the correlation
structure (
corStruct) of
object is returned either as
a named list with a single one-sided formula, or a single one-sided
formula, depending on the value of
asList. If
object
does not include a correlation structure, or if the correlation
structure does not include groups,
NULL is returned.
USAGE:
getGroupsFormula(object, asList)
REQUIRED ARGUMENTS:
object
an object inheriting from class
gls, representing
a generalized least squares fitted linear model.
OPTIONAL ARGUMENTS:
asList
an optional logical value. If
TRUE the returned
value with be a list of formulas; else, if
FALSE the returned
value will be a one-sided formula. Defaults to
FALSE.
VALUE:
if a correlation structure with groups is included in
object, a
one-sided formula, or a list with a single one-sided formula, with the
corresponding grouping structure, else
NULL.