Compute load centrality for nodes.
The load centrality of a node is the fraction of all shortest paths that pass through that node.
Parameters :  G : graph
normalized : bool, optional
weight : None or string, optional
cutoff : bool, optional


Returns :  nodes : dictionary

See also
Notes
Load centrality is slightly different than betweenness. For this load algorithm see the reference Scientific collaboration networks: II. Shortest paths, weighted networks, and centrality, M. E. J. Newman, Phys. Rev. E 64, 016132 (2001).