Return the Moral Graph
Returns the moralized graph of a given directed graph.
Parameters: G (NetworkX graph) – Directed graph Returns: H – The undirected moralized graph of G Return type: NetworkX graph
A moral graph is an undirected graph H = (V, E) generated from a directed Graph, where if a node has more than one parent node, edges between these parent nodes are inserted and all directed edges become undirected.
 Wray L. Buntine. 1995. Chain graphs for learning. In Proceedings of the Eleventh conference on Uncertainty in artificial intelligence (UAI’95)