npfun.Rd
\name{npfun}
\alias{npfun}
\title{
Dummy Function Returns Number of Points
}
\description{
Returns a summary function which is constant with value equal to
the number of points in the point pattern.
}
\usage{
npfun(X, ..., r)
}
\arguments{
\item{X}{
Point pattern.
}
\item{\dots}{
Ignored.
}
\item{r}{
Vector of values of the distance argument \eqn{r}.
}
}
\details{
This function is normally not called by the user. Instead it is passed
as an argument to the function \code{\link{psst}}.
}
\value{
Object of class \code{"fv"} representing a constant function.
}
\author{
\adrian
\ege and Jesper \ifelse{latex}{\out{M\o ller}}{Moller}.
}
\seealso{
\code{\link{psst}}
}
\examples{
fit0 <- ppm(cells, ~1, nd=10)
v <- psst(fit0, npfun)
}
\keyword{spatial}
\keyword{nonparametric}