ewCollessI {treebalance} | R Documentation |
Calculation of the equal weights Colless index for rooted binary trees
Description
This function calculates the equal weights Colless index for a
given rooted binary tree
.
is defined as
in which denotes the set of all inner vertices of
,
and in which
,
and
denote the number of
leaves in the pending subtrees that are rooted at
and the two direct
descendants of
. The equal weights Colless index is an imbalance index.
For and
the function returns
and a warning.
For details on the equal weigths Colless index, see
also Chapter 14 in "Tree balance indices: a comprehensive survey" (https://doi.org/10.1007/978-3-031-39800-1_14).
Usage
ewCollessI(tree)
Arguments
tree |
A rooted binary tree in phylo format. |
Value
ewCollessI
returns the equal weights Colless index of the given tree.
Author(s)
Luise Kuehn
References
A. O. Mooers and S. B. Heard. Inferring Evolutionary Process from Phylogenetic Tree Shape. The Quarterly Review of Biology, 72(1), 1997. doi: 10.1086/419657.
Examples
tree <- ape::read.tree(text="((((,),),(,)),(((,),),(,)));")
ewCollessI(tree)