Calculate the fraction of internal nodes with an imbalance greater than or equal to a given threshold.
nodeImbFrac(tree, threshold)
For any internal node, the function nodeImb
gives the number of tip descendants of each of the node's descending branches. The function nodeImbFrac
returns the fraction of internal nodes where the difference between these numbers is greater than or equal to the threshold.
## Find the fraction of internal nodes with an imbalance of 5 or more,
## in a random tree with 20 tips:
tree <- rtree(20)
plot(tree)
nodeImbFrac(tree,threshold=5)
#> [1] 0.2105263