area_per_pair {treestats}

Area per pair index

Description

The area per pair index calculates the sum of the number of edges on the path between all two leaves. Instead, the area per pair index (APP) can also be derived from the Sackin (S) and total cophenetic index (TC): APP = \frac{2}{n}\cdot S - \frac{4}{n(n-1)}\cdot TC APP = 2/n * S - 4/(n(n-1)) * TC

Usage

area_per_pair(phy, normalization = "none")

Arguments

phy

phylo object or ltable

normalization

"none" or "yule", in which case the acquired result is divided by the expectation for the Yule model.

Value

Area per pair index

References

T. Araújo 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.