Find the root of a tree (or the multiple roots for a non-rooted tree)
root(.tree)# S3 method for rtree
root(.tree)
roots(.tree)
# S3 method for rtree
roots(.tree)
A tree.
root
returns a node, the root of the tree if it exists;
if .tree
is not rooted, an error is thrown.
roots
returns a list of nodes, the roots of the tree.