\name{rtree}
\alias{rtree}
\alias{rcoal}
\alias{rmtree}
\title{Generates Random Trees}
\usage{
rtree(n, rooted = TRUE, tip.label = NULL, br = runif, ...)
rcoal(n, tip.label = NULL, br = "coalescent", ...)
rmtree(N, n, rooted = TRUE, tip.label = NULL, br = runif, ...)
}
\arguments{
  \item{n}{an integer giving the number of tips in the tree.}
  \item{rooted}{a logical indicating whether the tree should be rooted
    (the default).}
  \item{tip.label}{a character vector giving the tip labels; if not
    specified, the tips "t1", "t2", ..., are given.}
  \item{br}{an R function used to generate the branch lengths
    (\code{rtree}; use \code{NULL} to simulate only a topology), or the
    coalescence times (\code{rcoal}). For the latter, a genuine
    coalescent tree is simulated by default.}
  \item{...}{further argument(s) to be passed to \code{br}.}
  \item{N}{an integer giving the number of trees to generate.}
}
\description{
  These functions generate trees by splitting randomly the edges
  (\code{rtree}) or randomly clustering the tips (\code{rcoal}).
  \code{rtree} generates general (non-ultrametric) trees, and
  \code{rcoal} generates coalescent (ultrametric) trees.
}
\details{
  The trees generated are bifurcating. If \code{rooted = FALSE} in
  (\code{rtree}), the tree is trifurcating at its root.

  The default function to generate branch lengths in \code{rtree} is
  \code{runif}. If further arguments are passed to \code{br}, they need
  to be tagged (e.g., \code{min = 0, max = 10}).

  \code{rmtree} calls successively \code{rtree} and set the class of
  the returned object appropriately.
}
\value{
  An object of class \code{"phylo"} or of class \code{"multiPhylo"} in
  the case of \code{rmtree}.
}
\author{Emmanuel Paradis \email{Emmanuel.Paradis@mpl.ird.fr}}
\examples{
layout(matrix(1:9, 3, 3))
### Nine random trees:
for (i in 1:9) plot(rtree(20))
### Nine random cladograms:
for (i in 1:9) plot(rtree(20, FALSE), type = "c")
### generate 4 random trees of bird orders:
data(bird.orders)
layout(matrix(1:4, 2, 2))
for (i in 1:4)
  plot(rcoal(23, tip.label = bird.orders$tip.label), no.margin = TRUE)
layout(matrix(1))
}
\keyword{datagen}