Numeric vector of length 1.
If method = "prop"
, the number returned is the proportion of nodes in
the first tree for which there is a node in the second that contains the
same tips. Higher number represents greater similarity. If it is 1, the
trees are identical. If 0, the trees have no similarity whatsoever.
When method = "shallow"
, only those nodes tipwards of the median node
depth are taken into account. This will not be useful for small trees, but
may be helpful with larger datasets.
"PH85"
is the Penny and Hendy (1985) distance. This measure is the
default of dist.topo
. In this measure, the smaller the number,
the closer the trees are. If the trees are identical, this results in 0.