Description Usage Arguments Value Author(s) References Examples

This function calculates the symmetry nodes index *SNI(T)* for a given rooted
binary tree *T*. *SNI(T)* is defined as the number of inner vertices *v* that are not
symmetry nodes, i.e. the two pending subtrees rooted at the children of *v* do not
have the same tree shape.

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

1 | ```
symNodesI(tree)
``` |

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

`symNodesI`

returns the symmetry nodes index of the given tree.

Sophie Kersting

S. J. Kersting and M. Fischer. Measuring tree balance using symmetry nodes — A new balance index and its extremal properties. Mathematical Biosciences, page 108690, 2021. ISSN 0025-5564. doi:https://doi.org/10.1016/j.mbs.2021.108690

1 2 |

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