| getGroups.gls {nlme} | R Documentation |
If present, the grouping factor associated to the correlation
structure for the linear model represented by object is extracted.
## S3 method for class 'gls': getGroups(object, form, level, data, sep)
object |
an object inheriting from class gls, representing
a generalized least squares fitted linear model. |
form |
an optional formula with a conditioning expression on its
right hand side (i.e. an expression involving the |
operator). Defaults to formula(object). Not used. |
level |
a positive integer vector with the level(s) of grouping to be used when multiple nested levels of grouping are present. This argument is optional for most methods of this generic function and defaults to all levels of nesting. Not used. |
data |
a data frame in which to interpret the variables named in
form. Optional for most methods. Not used. |
sep |
character, the separator to use between group levels when
multiple levels are collapsed. The default is '/'. Not used. |
if the linear model represented by object incorporates a
correlation structure and the corresponding corStruct object
has a grouping factor, a vector with the group values is returned;
else, NULL is returned.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
fm1 <- gls(follicles ~ sin(2*pi*Time) + cos(2*pi*Time), Ovary,
correlation = corAR1(form = ~ 1 | Mare))
getGroups(fm1)