https://github.com/cran/pracma
Tip revision: 03698027c2d84118bd0c53c4a9a5b5d23676f388 authored by HwB on 01 October 2012, 00:00:00 UTC
version 1.2.0
version 1.2.0
Tip revision: 0369802
polyfit.Rd
\name{polyfit}
\alias{polyfit}
\alias{polyfit2}
\title{Fitting by Polynomial}
\description{
Polynomial curve fitting
}
\usage{
polyfit(x, y, n)
polyfit2(x, y, n = 1, p0 = NULL)
}
\arguments{
\item{x}{x-coordinates of points}
\item{y}{y-coordinates of points}
\item{n}{degree of the fitting polynomial}
\item{p0}{Point \code{p0 = [x0, y0]} }
}
\details{
\code{polyfit} finds the coefficients of a polynomial of degree \code{n}
fitting the points given by their \code{x}, \code{y} coordinates in a
least-squares sense.
\code{polyfit2} finds a polynomial that fits the data in a least-squares
sense, but also passes through \code{y0} for \code{x=x0}.
In \code{polyfit}, if \code{x}, \code{y} are matrices of the same size,
the coordinates are taken elementwise. Complex values are not allowed.
}
\value{
vector representing a polynomial
}
\seealso{
\code{\link{poly}}, \code{\link{polyval}}
}
\examples{
# Fitting the sine function by a polynomial
x <- seq(0, pi, length.out=25)
y <- sin(x)
p <- polyfit(x, y, 6)
\dontrun{
# Plot sin and fitted polynomial
plot(x, y, type="b")
yf <- polyval(p, x)
lines(x, yf, col="red")
grid()}
}
\keyword{ math }