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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