Description Usage Arguments Value Author(s) References Examples
This function calculates the s-shape statistic sShape(T) for a given rooted tree T. The tree must not necessarily be binary, however sShape only fulfils the definition of an imbalance index on the space of binary trees. sShape(T) is defined as
sShape(T)=ā_{u in V_in(T)} log(n_u-1)
in
which V_in(T) denotes the set of inner vertices of T
and n_u denotes the number of leaves
in the pending subtree that is rooted at u. An arbitrary logarithm base can be used
(for binary trees it is common to use base 2).
For n=1 the function returns sShape(T)=0 and a warning.
1 | sShapeI(tree, logbase = 2)
|
tree |
A rooted tree in phylo format. |
logbase |
The logarithm base that shall be used. |
sShapeI
returns the s-shape statistic of the given tree.
Luise Kuehn
M.G. Blum and O. Francois. Which random processes describe the tree of life? a large-scale study of phylogenetic tree imbalance. Systematic Biology, 2006.
1 2 |
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.