\name{balance}
\alias{balance}
\title{Balance of a Dichotomous Phylogenetic Tree}
\usage{
balance(phy)
}
\arguments{
\item{phy}{an object of class \code{"phylo"}.}
}
\description{
This function computes the balance of a phylogenetic tree, that is for
each node of the tree the numbers of descendants (i.e. tips) on each
of its daughter-branch. The tree must be fully dichotomous.
}
\value{
a numeric matrix with two columns and one row for each node of the
tree. The columns give the numbers of descendants on each
daughter-branches (the order of both columns being arbitrary). If the
phylogeny \code{phy} has an element \code{node.label}, this is used as
rownames for the returned matrix; otherwise the numbers (of mode
character) of the matrix \code{edge} of \code{phy} are used as rownames.
}
\references{
For a discussion on tree balance:
Aldous, D. J. (2001) Stochastic models and descriptive statistics for
phylogenetic trees, from Yule to today. \emph{Statistical Science},
\bold{16}, 23--34.
}
\author{Emmanuel Paradis \email{paradis@isem.univ-montp2.fr}}
\keyword{manip}