nlme (version 3.1-10)

getGroups.gls: Extract gls Object Groups

Description

If present, the grouping factor associated to the correlation structure for the linear model represented by object is extracted.

Usage

getGroups(object)

Value

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.

See Also

gls, corClasses

Examples

data(Ovary)
fm1 <- gls(follicles ~ sin(2*pi*Time) + cos(2*pi*Time), Ovary,
           correlation = corAR1(form = ~ 1 | Mare))
getGroups(fm1)