balance: Balance of a Dichotomous Phylogenetic Tree
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.
Usage
balance(phy)
Arguments
phy
an object of class "phylo".
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 phy has an element node.label, this is used as
rownames for the returned matrix; otherwise the numbers (of mode
character) of the matrix edge of 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. Statistical Science,
16, 23--34.