formula.femlm {FENmlm}

Extract the formula of a femlm fit

Description

This function extracts the formula from a femlm estimation. If the estimation was done with fixed-effects, they are added in the formula after a pipe (“|”). If the estimation was done with a non linear in parameters part, then this will be added in the formula in between I().

Usage

## S3 method for class 'femlm'
formula(x, type = c("full", "linear", "NL"), ...)

Arguments

x

An object of class femlm. Typically the result of a femlm estimation.

type

A character scalar. Default is type = "full" which gives back a formula containing the linear part of the model along with the clusters (if any) and the non-linear in parameters part (if any). If type = "linear" then only the linear formula is returned. If type = "NL" then only the non linear in parameters part is returned.

...

Not currently used.

Value

It returns a formula.

Author(s)

Laurent Berge

See Also

femlm, model.matrix.femlm, update.femlm, summary.femlm, vcov.femlm.

Examples

# simple estimation on iris data, clustering by "Species"
res = femlm(Sepal.Length ~ Sepal.Width + Petal.Length +
            Petal.Width | Species, iris)

# formula with the cluster variable
formula(res)
# linear part without the cluster variable
formula(res, "linear")