similarity

    def similarity(self, G=None, H=None, iters=20):
        """ Returns the graph similarity based on Neighbor Matching[Ref]
        Derived from 'wadsashika'_

        :param G: networkx graph of original graph (default: self.G)
        :param H: networkx graph of inferred graph (default: self.H)
        :param iter: number of iterations (default: 20)
        :return: float

        """
        if G is None:
            G = self.G
        if H is None:
            H = self.H

        n = len(G)

        gA = nx.adjacency_matrix(G)
        hA = nx.adjacency_matrix(H)
        s = np.identity(n)   # initial condition
        for i in range(iters):
            temp = (np.kron(gA, hA) + np.kron(gA.T, hA.T)) * s
            s = normalize(temp, norm='l1')

        return np.trace(s)