a vector of integers, the sequence of nodes of a path,
starting from st to en. In some graphs
(spanning trees) there is only one path between two nodes.
Arguments
amat
a square Boolean matrix with dimnames, the adjacency matrix of a graph.
st
an integer, the starting node.
en
an integer, the ending node.
path
a vector of integers, used in recursive calls. At the
beginning is NULL. It should not be modified by the user.
Author
Giovanni M. Marchetti, translating the original Python
code (see references).