Extract Knots from the Given Object

Methods for the generic function knots from the stats package to obtain internal or boundary knots from the objects produced by this package.

Usage

# S3 method for class 'splines2'
knots(Fn, type = c("internal", "boundary"), ...)

Arguments

Fn

An splines2 object produced by this package.

type

A character vector of length one indicating the type of knots to return. The available choices are "internal" for internal knots and "Boundary" for boundary knots.

...

Optional arguments that are not used now.

Value

A numerical vector.

Examples

library(splines2)

set.seed(123)
x <- rnorm(100)

## B-spline basis
bsMat <- bSpline(x, df = 8, degree = 3)

## extract internal knots placed based on the quantile of x
(internal_knots <- knots(bsMat))
#> [1] -0.69135780 -0.32593159  0.06175631  0.43518149  0.99962119

## extract boundary knots placed based on the range of x
boundary_knots <- knots(bsMat, type = "boundary")
all.equal(boundary_knots, range(x))
#> [1] TRUE