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\name{jaccard}
\alias{jaccard}
%- Also NEED an `\alias' for EACH other topic documented here.
\title{Jaccard distance matrix}
\description{
Computes Jaccard distances between the columns of a 0-1-matrix.
}
\usage{
jaccard(regmat)
}
%- maybe also `usage' for other objects documented here.
\arguments{
\item{regmat}{0-1-matrix. Columns are species, rows are regions.}
}
\details{
The Jaccard distance between two species is 1-(number of regions where
both species are present)/(number of regions where at least one
species is present). As a similarity coefficient, this is S22 in
Shi (1993).
Thank you to Laurent Buffat for improving this function!
}
\value{
A symmetrical matrix of Jaccard distances.
}
\references{
Shi, G. R. (1993) Multivariate data analysis in palaeoecology and
palaeobiogeography - a review. \emph{Palaeogeography,
Palaeoclimatology, Palaeoecology} 105, 199-234.
}
\author{Christian Hennig
\email{christian.hennig@unibo.it}
\url{https://www.unibo.it/sitoweb/christian.hennig/en}}
\seealso{
\code{\link{kulczynski}}, \code{\link{dicedist}}
}
\examples{
options(digits=4)
data(kykladspecreg)
jaccard(t(kykladspecreg))
}
\keyword{cluster}% at least one, from doc/KEYWORDS
\keyword{spatial}% __ONLY ONE__ keyword per line
|
