Mercurial > repos > shellac > sam_consensus_v3
diff env/lib/python3.9/site-packages/networkx/linalg/modularitymatrix.py @ 0:4f3585e2f14b draft default tip
"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"
author | shellac |
---|---|
date | Mon, 22 Mar 2021 18:12:50 +0000 |
parents | |
children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/env/lib/python3.9/site-packages/networkx/linalg/modularitymatrix.py Mon Mar 22 18:12:50 2021 +0000 @@ -0,0 +1,158 @@ +"""Modularity matrix of graphs. +""" +import networkx as nx +from networkx.utils import not_implemented_for + +__all__ = ["modularity_matrix", "directed_modularity_matrix"] + + +@not_implemented_for("directed") +@not_implemented_for("multigraph") +def modularity_matrix(G, nodelist=None, weight=None): + r"""Returns the modularity matrix of G. + + The modularity matrix is the matrix B = A - <A>, where A is the adjacency + matrix and <A> is the average adjacency matrix, assuming that the graph + is described by the configuration model. + + More specifically, the element B_ij of B is defined as + + .. math:: + A_{ij} - {k_i k_j \over 2 m} + + where k_i is the degree of node i, and where m is the number of edges + in the graph. When weight is set to a name of an attribute edge, Aij, k_i, + k_j and m are computed using its value. + + Parameters + ---------- + G : Graph + A NetworkX graph + + nodelist : list, optional + The rows and columns are ordered according to the nodes in nodelist. + If nodelist is None, then the ordering is produced by G.nodes(). + + weight : string or None, optional (default=None) + The edge attribute that holds the numerical value used for + the edge weight. If None then all edge weights are 1. + + Returns + ------- + B : Numpy matrix + The modularity matrix of G. + + Examples + -------- + >>> k = [3, 2, 2, 1, 0] + >>> G = nx.havel_hakimi_graph(k) + >>> B = nx.modularity_matrix(G) + + + See Also + -------- + to_numpy_array + modularity_spectrum + adjacency_matrix + directed_modularity_matrix + + References + ---------- + .. [1] M. E. J. Newman, "Modularity and community structure in networks", + Proc. Natl. Acad. Sci. USA, vol. 103, pp. 8577-8582, 2006. + """ + if nodelist is None: + nodelist = list(G) + A = nx.to_scipy_sparse_matrix(G, nodelist=nodelist, weight=weight, format="csr") + k = A.sum(axis=1) + m = k.sum() * 0.5 + # Expected adjacency matrix + X = k * k.transpose() / (2 * m) + return A - X + + +@not_implemented_for("undirected") +@not_implemented_for("multigraph") +def directed_modularity_matrix(G, nodelist=None, weight=None): + """Returns the directed modularity matrix of G. + + The modularity matrix is the matrix B = A - <A>, where A is the adjacency + matrix and <A> is the expected adjacency matrix, assuming that the graph + is described by the configuration model. + + More specifically, the element B_ij of B is defined as + + .. math:: + B_{ij} = A_{ij} - k_i^{out} k_j^{in} / m + + where :math:`k_i^{in}` is the in degree of node i, and :math:`k_j^{out}` is the out degree + of node j, with m the number of edges in the graph. When weight is set + to a name of an attribute edge, Aij, k_i, k_j and m are computed using + its value. + + Parameters + ---------- + G : DiGraph + A NetworkX DiGraph + + nodelist : list, optional + The rows and columns are ordered according to the nodes in nodelist. + If nodelist is None, then the ordering is produced by G.nodes(). + + weight : string or None, optional (default=None) + The edge attribute that holds the numerical value used for + the edge weight. If None then all edge weights are 1. + + Returns + ------- + B : Numpy matrix + The modularity matrix of G. + + Examples + -------- + >>> G = nx.DiGraph() + >>> G.add_edges_from( + ... ( + ... (1, 2), + ... (1, 3), + ... (3, 1), + ... (3, 2), + ... (3, 5), + ... (4, 5), + ... (4, 6), + ... (5, 4), + ... (5, 6), + ... (6, 4), + ... ) + ... ) + >>> B = nx.directed_modularity_matrix(G) + + + Notes + ----- + NetworkX defines the element A_ij of the adjacency matrix as 1 if there + is a link going from node i to node j. Leicht and Newman use the opposite + definition. This explains the different expression for B_ij. + + See Also + -------- + to_numpy_array + modularity_spectrum + adjacency_matrix + modularity_matrix + + References + ---------- + .. [1] E. A. Leicht, M. E. J. Newman, + "Community structure in directed networks", + Phys. Rev Lett., vol. 100, no. 11, p. 118703, 2008. + """ + if nodelist is None: + nodelist = list(G) + A = nx.to_scipy_sparse_matrix(G, nodelist=nodelist, weight=weight, format="csr") + k_in = A.sum(axis=0) + k_out = A.sum(axis=1) + m = k_in.sum() + # Expected adjacency matrix + X = k_out * k_in / m + return A - X