Finds the Colless number for a tree.
Note that the package apTreeshape has a function colless to compute the Colless imbalance with additional options to normalise it based on the model;
we include this simple function here for convenience within this package, and for use on objects of class phylo and phylo4.
colless.phylo(tree, normalise = TRUE)Arguments
- tree
a tree of class
phyloorphylo4. The tree should be binary and rooted; if not it will be coerced into a binary rooted tree using multi2di, if possible.- normalise
option to normalise the result by dividing by the number of tip pairs. Defaults to
TRUE.
Value
The Colless imbalance number of the tree.
Examples
## Find the Colless imbalance of a random tree with 10 tips:
tree <- rtree(10)
plot(tree)
colless.phylo(tree)
#> [1] 0.2777778