Description Usage Arguments Value Author(s) References Examples
This function calculates the average leaf depth N(T) for a given rooted tree T. The tree must not necessarily be binary. N(T) is defined as
N(T)=(1/n) * ∑_{u in V_in(T)} n_u
in which n denotes the number of leaves in T,
V_in(T) denotes the set of inner nodes of T and
n_u denotes the number of leaves in the pending subtree that is rooted
at the inner node u. Note that N(T) can also be
computed from the Sackin index S(T) as N(T)=1/n*S(T).
The average leaf depth is an imbalance index.
For n=1 the function returns N(T)=0 and a warning.
1 | avgLeafDepI(tree)
|
tree |
A rooted tree in phylo format. |
avgLeafDepI
returns the average leaf depth of the given tree.
Luise Kuehn
M. J. Sackin. "Good" and "Bad" Phenograms. Systematic Biology, 21(2):225-226, 1972. doi: 10.1093/sysbio/21.2.225.
K.-T. Shao and R. R. Sokal. Tree Balance. Systematic Zoology, 39(3):266, 1990.
doi: 10.2307/2992186.
1 2 | tree <- ape::read.tree(text="((((,),),(,)),(((,),),(,)));")
avgLeafDepI(tree)
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