Tests whether a 2 x n matrix represents a rooted tree in the
format accepted by the oncomodel package.
Usage
is.tree(tree)
Arguments
tree
a 2 x n matrix.
Details
In the accepted format, the columns of the integer matrix represent the edges of
the tree, with the entry in the first row being closer to the root. The
leaves have to be the smallest integers of the matrix. If an edge
has a smaller column index than a second one, it may not be on the
path from the second edge to the root (the order of the columns has to
be compatible with the partial order of the edges of the tree).