nlme (version 3.1-86)

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

## S3 method for class 'gls':
getGroups(object, form, level, data, sep)

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

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