https://github.com/cran/fields
Tip revision: e0f3f5c70e9024e8948914ea64f7cd3a35677402 authored by Doug Nychka on 13 May 2003, 00:00:00 UTC
version 1.3-1
version 1.3-1
Tip revision: e0f3f5c
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.