Description Usage Arguments Value Author(s) References Examples

This function calculates the variance of leaf depths index *VLD(T)*
for a given rooted tree *T*. The tree must not necessarily be binary.
*VLD(T)* is defined as

*
VLD(T)=1/n * ∑_{x in V_L(T)} (δ(x)-N(T))^2*

in which *n* denotes the number of leaves of *T*, *V_L(T)*
denotes the set of leaves of *T*, *δ(x)* denotes the depth of
the leaf *x* and *N(T)* denotes the average leaf depth of *T*.

For *n=1* the function returns *VLD(T)=0* and a warning.

1 | ```
varLeafDepI(tree)
``` |

`tree` |
A rooted tree in phylo format. |

`varLeafDepI`

returns the variance of leaf depths index of the given tree.

Sophie Kersting

T. M. Coronado, A. Mir, F. Rosselló, and L. Rotger. On Sackin's original proposal: the variance of the leaves' depths as a phylogenetic balance index. BMC Bioinformatics, 21(1), 2020. doi: 10.1186/s12859-020-3405-1. URL https://doi.org/10.1186/s12859-020-3405-1.

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="((((,),),(,)),(((,),),(,)));")
varLeafDepI(tree)
``` |

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