getGroupsFormula.gls {nlme} | R Documentation |
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.
getGroupsFormula(object, asList)
object |
an object inheriting from class gls , representing
a generalized least squares fitted linear model. |
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 . |
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
.
Jose Pinheiro and Douglas Bates
library(nlme) data(Ovary) fm1 <- gls(follicles ~ sin(2*pi*Time) + cos(2*pi*Time), Ovary, correlation = corAR1(form = ~ 1 | Mare)) getGroupsFormula(fm1)