compute.brlen {ape}R Documentation

Branch lengths Computation

Description

Compute branch lengths.

Usage

        compute.brlen(phy, method="Grafen", power=1)

Arguments

phy An object of class phylo representing the tree.
method The method to use to compute lengths. Only Grafen's 1989 method is implemented for now.
power The power at which heights must be raised (see below).

Details

Grafen's (1989) computation of branch lengths: Each node is given a 'height', namely the number of leaves of the subtree minus one, 0 for leaves. Each height is scaled so that root height is 1, and then raised at power 'rho' (>0). Branch lengths are then computed as the difference between height of lower node and height of upper node.

Value

An object of class phylo with branch lengths.

Author(s)

Julien Dutheil julien.dutheil@univ-montp2.fr

References

Grafen, A. (1989) The phylogenetic regression. Philosophical Transactions of the Royal society of London. Series B. Biological Sciences, 326, 119–157.

See Also

read.tree for a description of phylo objects.

Examples

        data(bird.orders)
        split.screen(c(2,2))
        screen(1)
        plot(compute.brlen(bird.orders, power=1), main=expression(rho==1))
        screen(2)
        plot(compute.brlen(bird.orders, power=3), main=expression(rho==3))
        screen(3)
        plot(compute.brlen(bird.orders, power=0.5), main=expression(rho==0.5))
        screen(4)
        plot(compute.brlen(bird.orders, power=0.1), main=expression(rho==0.1))
        close.screen(all=TRUE)

[Package ape version 1.5 Index]