A directed graph. Some methods in this class have two versions, one that operates on graph nodes, and another that operates on node weights. The latter form is called the
weights version. More specifically, the weights version of an operation takes individual node weights or arrays of weights as arguments, and, when applicable, returns individual weights or arrays of weights.
Multiple edges in a graph can be directed between the same pair of nodes. Thus, directed multigraphs are supported.
@author Yuhong Xiong, Jie Liu, Paul Whitaker, Shuvra S. Bhattacharyya,Shahrooz Shahparnia
@version $Id: DirectedGraph.java,v 1.121 2006/03/29 00:01:03 cxh Exp $
@since Ptolemy II 0.2
@Pt.ProposedRating Yellow (pwhitake)
@Pt.AcceptedRating Yellow (pwhitake)