https://github.com/cran/fields
Tip revision: beb6c9118b4f355fc630943f00274a7df8714fe1 authored by Doug Nychka on 26 April 2007, 00:00:00 UTC
version 3.5
version 3.5
Tip revision: beb6c91
splint.Rd
\name{splint}
\alias{splint}
\title{
Cubic spline interpolation
}
\description{
A fast, FORTRAN based function for cubic spline interpolation.
}
\usage{
splint(x, y, xgrid, derivative=0)
}
\arguments{
\item{x}{
The x values that define the curve or a two column matrix of
x and y values.
}
\item{y}{
The y values that are paired with the x's.
}
\item{xgrid}{
The grid to evaluate the fitted cubic interpolating curve.
}
\item{derivative}{
Indicates whether the function or a a first or second derivative
should be evaluated.
}
}
\value{
A vector consisting of the spline evaluated at the grid values.
}
\details{
Fits a piecewise interpolating cubic polynomial to the x and y values
assuming that the second and third derivatives are zero at the range of the x
values. For this reason extrapolation outside the range of the x
values will be a linear function.
}
\section{References}{
See Additive Models by Hastie and Tibshriani.
}
\seealso{
sreg, Tps
}
\examples{
x<- seq( 0, 120,,200)
splint(rat.diet$t, rat.diet$trt,x )-> y
plot( rat.diet$t, rat.diet$trt)
lines( x,y)
#( this is weird!)
}
\keyword{smooth}
% docclass is function
% Converted by Sd2Rd version 1.21.