nlme (version 3.1-10)

getGroupsFormula.gls: Extract gls Object Grouping Formula

Description

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)

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.

See Also

corClasses, getGroups.gls

Examples

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