Description Usage Arguments Value Author(s) References Examples
This function calculates the equal weights Colless index I_2(T) for a given rooted binary tree T. I_2(T) is defined as
I_2(T)=1/(n-2)* ∑ |n_ua-n_ub|/(n_u-2) over all u in V_in(T) with n_u>2
in which V_in(T) denotes the set of all inner vertices of T,
and in which n_u, n_ua and n_ub denote the number of
leaves in the pending subtrees that are rooted at u and the two direct
descendants of u. The equal weights Colless index is an imbalance index.
For n=1 and n=2 the function returns I_2(T)=0 and a warning.
A rooted binary tree in phylo format.
ewCollessI returns the equal weights Colless index of the given tree.
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.
tree <- ape::read.tree(text="((((,),),(,)),(((,),),(,)));") ewCollessI(tree)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.