rogersI {treebalance} | R Documentation |
Calculation of the Rogers J index for rooted binary trees
Description
This function calculates the Rogers J index for a given rooted
binary tree
. It is defined as the number of inner vertices whose balance
value is unequal to zero, more precisely
in which denotes the set of all inner vertices
of
, and in which
and
denote the number of leaves in the two pending subtrees that are
rooted at the direct descendants of
.
Special cases: For , the function returns
and a warning.
For details on the Rogers J index, see
also Chapter 19 in "Tree balance indices: a comprehensive survey" (https://doi.org/10.1007/978-3-031-39800-1_19).
Usage
rogersI(tree)
Arguments
tree |
A rooted binary tree in phylo format. |
Value
rogersI
returns the Rogers J index of the given tree.
Author(s)
Sophie Kersting
References
J. S. Rogers. Central Moments and Probability Distributions of Three Measures of Phylogenetic Tree Imbalance. Systematic Biology, 45(1):99-110, 1996. doi: 10.1093/sysbio/45.1.99.
Examples
tree <- ape::read.tree(text="((((,),),(,)),(((,),),(,)));")
rogersI(tree)