Monotone Inverse Spline

Description

Create a monotone inverse of a monotone natural spline.

Usage

backSpline(object)

Arguments

Value

An object of class polySpline that contains the piecewise polynomial representation of a function that has the appropriate values and derivatives at the knot positions to be an inverse of the spline represented by object. Technically this object is not a spline because the second derivative is not constrained to be continuous at the knot positions. However, it is often a much better approximation to the inverse than fitting an interpolation spline to the y/x pairs.

Author(s)

Douglas Bates and Bill Venables

See Also

interpSpline

Examples

require(graphics)
ispl <- interpSpline( women$height, women$weight )
bspl <- backSpline( ispl )
plot( bspl )                   # plots over the range of the knots
points( women$weight, women$height )

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(splines)
> png(filename="/home/ddbj/snapshot/RGM3/R_rel/result/splines/backSpline.Rd_%03d_medium.png", width=480, height=480)
> ### Name: backSpline
> ### Title: Monotone Inverse Spline
> ### Aliases: backSpline
> ### Keywords: models
> 
> ### ** Examples
> 
> require(graphics)
> ispl <- interpSpline( women$height, women$weight )
> bspl <- backSpline( ispl )
> plot( bspl )                   # plots over the range of the knots
> points( women$weight, women$height )
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>