areaPerPairI {treebalance} | R Documentation |
Calculation of the area per pair index for rooted trees
Description
This function calculates the area per pair index for a given rooted
tree
. The tree must not necessarily be binary.
is defined as
in which denotes the
number of leaves in
, and
denotes the number of edges on the path between the two
leaves
and
. Note that
can also be
computed from the Sackin index
and the total cophenetic
index
of
as
enabling efficient computation.
The area per pair index does not fulfill the definition of an (im)balance
index given in "Tree balance indices: a comprehensive survey" (Fischer et al., 2023).
For details on the area per pair index, see
also Chapter 24 in "Tree balance indices: a comprehensive survey" (https://doi.org/10.1007/978-3-031-39800-1_24).
Usage
areaPerPairI(tree)
Arguments
tree |
A rooted tree in phylo format. |
Value
areaPerPairI
returns the area per pair index of the given tree.
Author(s)
Luise Kuehn
References
T. Araujo Lima, F. M. D. Marquitti, and M. A. M. de Aguiar. Measuring Tree Balance with Normalized Tree Area. arXiv e-prints, art. arXiv:2008.12867, 2020.
Examples
tree <- ape::read.tree(text="((((,),),(,)),(((,),),(,)));")
areaPerPairI(tree)