pedWorks.py 文件源码

def out_degree_centrality(G):
    """Compute the out-degree centrality for nodes.

    The out-degree centrality for a node v is the fraction of nodes its
    outgoing edges are connected to.

    Parameters
    ----------
    G : graph
        A NetworkX graph

    Returns
    -------
    nodes : dictionary
        Dictionary of nodes with out-degree centrality as values.

    See Also
    --------
    degree_centrality, in_degree_centrality

    Notes
    -----
    The degree centrality values are normalized by dividing by the maximum
    possible degree in a simple graph n-1 where n is the number of nodes in G.

    For multigraphs or graphs with self loops the maximum degree might
    be higher than n-1 and values of degree centrality greater than 1
    are possible.
    """
    if not G.is_directed():
        raise nx.NetworkXError( \
            "out_degree_centrality() not defined for undirected graphs.")
    centrality = {}
    s = 1.0 / (len(G) - 1.0)
    centrality = dict((n, d * s) for n, d in G.out_degree_iter())
    return centrality