https://github.com/cran/fda
Tip revision: 877347f65135b34c238ac4f27de992aa38d15347 authored by J. O. Ramsay on 03 November 2009, 00:00:00 UTC
version 2.4.0
version 2.4.0
Tip revision: 877347f
lambda2df.Rd
\name{lambda2df}
\alias{lambda2df}
\title{
Convert Smoothing Parameter to Degrees of Freedom
}
\description{
The degree of roughness of an estimated function is controlled by a
smoothing parameter $lambda$ that directly multiplies the penalty.
However, it can be difficult to interpret or choose this value, and it
is often easier to determine the roughness by choosing a value that is
equivalent of the degrees of freedom used by the smoothing procedure.
This function converts a multipler $lambda$ into a degrees of freedom value.
}
\usage{
lambda2df(argvals, basisobj, wtvec=rep(1, n),
Lfdobj=NULL, lambda=0, returnMatrix=FALSE)
}
\arguments{
\item{argvals}{
a vector containing the argument values used in the
smooth of the data.
}
\item{basisobj}{
the basis object used in the smoothing of the data.
}
\item{wtvec}{
the weight vector, if any, that was used in the smoothing
of the data.
}
\item{Lfdobj}{
the linear differential operator object used to defining
the roughness penalty employed in smoothing the data.
}
\item{lambda}{
the smoothing parameter to be converted.
}
\item{returnMatrix}{
logical: If TRUE, a two-dimensional is returned using a
special class from the Matrix package.
}
}
\value{
the equivalent degrees of freedom value.
}
\seealso{
\code{\link{df2lambda}}
}
% docclass is function
\keyword{smooth}