Mercurial > repos > shellac > sam_consensus_v3
diff env/lib/python3.9/site-packages/networkx/algorithms/connectivity/tests/test_kcutsets.py @ 0:4f3585e2f14b draft default tip
"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"
author | shellac |
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date | Mon, 22 Mar 2021 18:12:50 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/env/lib/python3.9/site-packages/networkx/algorithms/connectivity/tests/test_kcutsets.py Mon Mar 22 18:12:50 2021 +0000 @@ -0,0 +1,266 @@ +# Jordi Torrents +# Test for k-cutsets +import itertools +import pytest + +import networkx as nx +from networkx.algorithms import flow +from networkx.algorithms.connectivity.kcutsets import _is_separating_set + +MAX_CUTSETS_TO_TEST = 4 # originally 100. cut to decrease testing time + +flow_funcs = [ + flow.boykov_kolmogorov, + flow.dinitz, + flow.edmonds_karp, + flow.preflow_push, + flow.shortest_augmenting_path, +] + + +## +# Some nice synthetic graphs +## +def graph_example_1(): + G = nx.convert_node_labels_to_integers( + nx.grid_graph([5, 5]), label_attribute="labels" + ) + rlabels = nx.get_node_attributes(G, "labels") + labels = {v: k for k, v in rlabels.items()} + + for nodes in [ + (labels[(0, 0)], labels[(1, 0)]), + (labels[(0, 4)], labels[(1, 4)]), + (labels[(3, 0)], labels[(4, 0)]), + (labels[(3, 4)], labels[(4, 4)]), + ]: + new_node = G.order() + 1 + # Petersen graph is triconnected + P = nx.petersen_graph() + G = nx.disjoint_union(G, P) + # Add two edges between the grid and P + G.add_edge(new_node + 1, nodes[0]) + G.add_edge(new_node, nodes[1]) + # K5 is 4-connected + K = nx.complete_graph(5) + G = nx.disjoint_union(G, K) + # Add three edges between P and K5 + G.add_edge(new_node + 2, new_node + 11) + G.add_edge(new_node + 3, new_node + 12) + G.add_edge(new_node + 4, new_node + 13) + # Add another K5 sharing a node + G = nx.disjoint_union(G, K) + nbrs = G[new_node + 10] + G.remove_node(new_node + 10) + for nbr in nbrs: + G.add_edge(new_node + 17, nbr) + G.add_edge(new_node + 16, new_node + 5) + return G + + +def torrents_and_ferraro_graph(): + G = nx.convert_node_labels_to_integers( + nx.grid_graph([5, 5]), label_attribute="labels" + ) + rlabels = nx.get_node_attributes(G, "labels") + labels = {v: k for k, v in rlabels.items()} + + for nodes in [(labels[(0, 4)], labels[(1, 4)]), (labels[(3, 4)], labels[(4, 4)])]: + new_node = G.order() + 1 + # Petersen graph is triconnected + P = nx.petersen_graph() + G = nx.disjoint_union(G, P) + # Add two edges between the grid and P + G.add_edge(new_node + 1, nodes[0]) + G.add_edge(new_node, nodes[1]) + # K5 is 4-connected + K = nx.complete_graph(5) + G = nx.disjoint_union(G, K) + # Add three edges between P and K5 + G.add_edge(new_node + 2, new_node + 11) + G.add_edge(new_node + 3, new_node + 12) + G.add_edge(new_node + 4, new_node + 13) + # Add another K5 sharing a node + G = nx.disjoint_union(G, K) + nbrs = G[new_node + 10] + G.remove_node(new_node + 10) + for nbr in nbrs: + G.add_edge(new_node + 17, nbr) + # Commenting this makes the graph not biconnected !! + # This stupid mistake make one reviewer very angry :P + G.add_edge(new_node + 16, new_node + 8) + + for nodes in [(labels[(0, 0)], labels[(1, 0)]), (labels[(3, 0)], labels[(4, 0)])]: + new_node = G.order() + 1 + # Petersen graph is triconnected + P = nx.petersen_graph() + G = nx.disjoint_union(G, P) + # Add two edges between the grid and P + G.add_edge(new_node + 1, nodes[0]) + G.add_edge(new_node, nodes[1]) + # K5 is 4-connected + K = nx.complete_graph(5) + G = nx.disjoint_union(G, K) + # Add three edges between P and K5 + G.add_edge(new_node + 2, new_node + 11) + G.add_edge(new_node + 3, new_node + 12) + G.add_edge(new_node + 4, new_node + 13) + # Add another K5 sharing two nodes + G = nx.disjoint_union(G, K) + nbrs = G[new_node + 10] + G.remove_node(new_node + 10) + for nbr in nbrs: + G.add_edge(new_node + 17, nbr) + nbrs2 = G[new_node + 9] + G.remove_node(new_node + 9) + for nbr in nbrs2: + G.add_edge(new_node + 18, nbr) + return G + + +# Helper function +def _check_separating_sets(G): + for cc in nx.connected_components(G): + if len(cc) < 3: + continue + Gc = G.subgraph(cc) + node_conn = nx.node_connectivity(Gc) + all_cuts = nx.all_node_cuts(Gc) + # Only test a limited number of cut sets to reduce test time. + for cut in itertools.islice(all_cuts, MAX_CUTSETS_TO_TEST): + assert node_conn == len(cut) + assert not nx.is_connected(nx.restricted_view(G, cut, [])) + + +@pytest.mark.slow +def test_torrents_and_ferraro_graph(): + G = torrents_and_ferraro_graph() + _check_separating_sets(G) + + +def test_example_1(): + G = graph_example_1() + _check_separating_sets(G) + + +def test_random_gnp(): + G = nx.gnp_random_graph(100, 0.1, seed=42) + _check_separating_sets(G) + + +def test_shell(): + constructor = [(20, 80, 0.8), (80, 180, 0.6)] + G = nx.random_shell_graph(constructor, seed=42) + _check_separating_sets(G) + + +def test_configuration(): + deg_seq = nx.random_powerlaw_tree_sequence(100, tries=5, seed=72) + G = nx.Graph(nx.configuration_model(deg_seq)) + G.remove_edges_from(nx.selfloop_edges(G)) + _check_separating_sets(G) + + +def test_karate(): + G = nx.karate_club_graph() + _check_separating_sets(G) + + +def _generate_no_biconnected(max_attempts=50): + attempts = 0 + while True: + G = nx.fast_gnp_random_graph(100, 0.0575, seed=42) + if nx.is_connected(G) and not nx.is_biconnected(G): + attempts = 0 + yield G + else: + if attempts >= max_attempts: + msg = f"Tried {attempts} times: no suitable Graph." + raise Exception(msg) + else: + attempts += 1 + + +def test_articulation_points(): + Ggen = _generate_no_biconnected() + for i in range(1): # change 1 to 3 or more for more realizations. + G = next(Ggen) + articulation_points = list({a} for a in nx.articulation_points(G)) + for cut in nx.all_node_cuts(G): + assert cut in articulation_points + + +def test_grid_2d_graph(): + # All minimum node cuts of a 2d grid + # are the four pairs of nodes that are + # neighbors of the four corner nodes. + G = nx.grid_2d_graph(5, 5) + solution = [{(0, 1), (1, 0)}, {(3, 0), (4, 1)}, {(3, 4), (4, 3)}, {(0, 3), (1, 4)}] + for cut in nx.all_node_cuts(G): + assert cut in solution + + +def test_disconnected_graph(): + G = nx.fast_gnp_random_graph(100, 0.01, seed=42) + cuts = nx.all_node_cuts(G) + pytest.raises(nx.NetworkXError, next, cuts) + + +@pytest.mark.slow +def test_alternative_flow_functions(): + graphs = [nx.grid_2d_graph(4, 4), nx.cycle_graph(5)] + for G in graphs: + node_conn = nx.node_connectivity(G) + for flow_func in flow_funcs: + all_cuts = nx.all_node_cuts(G, flow_func=flow_func) + # Only test a limited number of cut sets to reduce test time. + for cut in itertools.islice(all_cuts, MAX_CUTSETS_TO_TEST): + assert node_conn == len(cut) + assert not nx.is_connected(nx.restricted_view(G, cut, [])) + + +def test_is_separating_set_complete_graph(): + G = nx.complete_graph(5) + assert _is_separating_set(G, {0, 1, 2, 3}) + + +def test_is_separating_set(): + for i in [5, 10, 15]: + G = nx.star_graph(i) + max_degree_node = max(G, key=G.degree) + assert _is_separating_set(G, {max_degree_node}) + + +def test_non_repeated_cuts(): + # The algorithm was repeating the cut {0, 1} for the giant biconnected + # component of the Karate club graph. + K = nx.karate_club_graph() + bcc = max(list(nx.biconnected_components(K)), key=len) + G = K.subgraph(bcc) + solution = [{32, 33}, {2, 33}, {0, 3}, {0, 1}, {29, 33}] + cuts = list(nx.all_node_cuts(G)) + if len(solution) != len(cuts): + print(nx.info(G)) + print(f"Solution: {solution}") + print(f"Result: {cuts}") + assert len(solution) == len(cuts) + for cut in cuts: + assert cut in solution + + +def test_cycle_graph(): + G = nx.cycle_graph(5) + solution = [{0, 2}, {0, 3}, {1, 3}, {1, 4}, {2, 4}] + cuts = list(nx.all_node_cuts(G)) + assert len(solution) == len(cuts) + for cut in cuts: + assert cut in solution + + +def test_complete_graph(): + G = nx.complete_graph(5) + solution = [{0, 1, 2, 3}, {0, 1, 2, 4}, {0, 1, 3, 4}, {0, 2, 3, 4}, {1, 2, 3, 4}] + cuts = list(nx.all_node_cuts(G)) + assert len(solution) == len(cuts) + for cut in cuts: + assert cut in solution