chronopl(phy, lambda, node.age = 1, node = "root", CV = FALSE)"phylo".node.age; "root" is a short-cut the number of the
node."phylo" with branch lengths as estimated by
the function. There are two or three further attributes:CV = TRUE). lambda must be given. The known ages are given in
node.age, and the correponding node numbers in node.
These two arguments must obviously be of the same length. By default,
an age of 1 is assumed for the root, and the ages of the other nodes
are estimated.
The cross-validation used here is different from the one proposed by Sanderson (2002). Here, each tip is dropped successively and the analysis is repeated with the reduced tree: the estimated dates for the remaining nodes are compared with the estimates from the full data. For the $i$th tip the following is calculated:
$$\sum_{j=1}^{n-2}{\frac{(t_j - t_j^{-i})^2}{t_j}}$$,
where $t_j$ is the estimated date for the $j$th node with the full phylogeny, $t_j^{-i}$ is the estimated date for the $j$th node after removing tip $i$ from the tree, and $n$ is the number of tips.
chronogram, ratogram,
NPRS.criterion, chronoMPL