Exemplo n.º 1
0
def test_brandes_erlebach_book():
    # Figure 1 chapter 7: Connectivity
    # http://www.informatik.uni-augsburg.de/thi/personen/kammer/Graph_Connectivity.pdf
    G = nx.Graph()
    G.add_edges_from([(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 6), (3, 4),
                      (3, 6), (4, 6), (4, 7), (5, 7), (6, 8), (6, 9), (7, 8),
                      (7, 10), (8, 11), (9, 10), (9, 11), (10, 11)])
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        # edge cutsets
        assert_equal(3, len(nx.minimum_edge_cut(G, 1, 11, **kwargs)),
                     msg=msg.format(flow_func.__name__))
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        # Node 5 has only two edges
        assert_equal(2, len(edge_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
        # node cuts
        assert_equal(set([6, 7]), minimum_st_node_cut(G, 1, 11, **kwargs),
                     msg=msg.format(flow_func.__name__))
        assert_equal(set([6, 7]), nx.minimum_node_cut(G, 1, 11, **kwargs),
                     msg=msg.format(flow_func.__name__))
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert_equal(2, len(node_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
def test_brandes_erlebach_book():
    # Figure 1 chapter 7: Connectivity
    # http://www.informatik.uni-augsburg.de/thi/personen/kammer/Graph_Connectivity.pdf
    G = nx.Graph()
    G.add_edges_from([(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 6), (3, 4),
                      (3, 6), (4, 6), (4, 7), (5, 7), (6, 8), (6, 9), (7, 8),
                      (7, 10), (8, 11), (9, 10), (9, 11), (10, 11)])
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        errmsg = f"Assertion failed in function: {flow_func.__name__}"
        # edge cutsets
        assert 3 == len(nx.minimum_edge_cut(G, 1, 11, **kwargs)), errmsg
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        # Node 5 has only two edges
        assert 2 == len(edge_cut), errmsg
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert not nx.is_connected(H), errmsg
        # node cuts
        assert {6, 7} == minimum_st_node_cut(G, 1, 11, **kwargs), errmsg
        assert {6, 7} == nx.minimum_node_cut(G, 1, 11, **kwargs), errmsg
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert 2 == len(node_cut), errmsg
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert not nx.is_connected(H), errmsg
Exemplo n.º 3
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def test_brandes_erlebach_book():
    # Figure 1 chapter 7: Connectivity
    # http://www.informatik.uni-augsburg.de/thi/personen/kammer/Graph_Connectivity.pdf
    G = nx.Graph()
    G.add_edges_from([(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 6), (3, 4),
                      (3, 6), (4, 6), (4, 7), (5, 7), (6, 8), (6, 9), (7, 8),
                      (7, 10), (8, 11), (9, 10), (9, 11), (10, 11)])
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        # edge cutsets
        assert_equal(3, len(nx.minimum_edge_cut(G, 1, 11, **kwargs)),
                     msg=msg.format(flow_func.__name__))
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        # Node 5 has only two edges
        assert_equal(2, len(edge_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
        # node cuts
        assert_equal(set([6, 7]), minimum_st_node_cut(G, 1, 11, **kwargs),
                     msg=msg.format(flow_func.__name__))
        assert_equal(set([6, 7]), nx.minimum_node_cut(G, 1, 11, **kwargs),
                     msg=msg.format(flow_func.__name__))
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert_equal(2, len(node_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
Exemplo n.º 4
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def print_robustness(): #What is the smallest number of nodes that can be removed from this graph in order to disconnect it?
    # 1) whole graph:
    nx.node_connectivity(G) #1 - too small, When higher - it is good
    nx.minimum_node_cut(G) #{'Чкаловская'}
    nx.edge_connectivity(G) # 1
    nx.minimum_edge_cut(G) #{('Марьино', 'Чкаловская')}
    # 2) concrete path
    nx.node_connectivity(G, 'Киевская', 'Чкаловская') #2 - better
    nx.minimum_node_cut(G, 'Киевская', 'Чкаловская') #{'Курская', 'Сретенский бульвар'}
    nx.edge_connectivity(G, 'Киевская', 'Чкаловская') #2 - better
    nx.minimum_edge_cut(G, 'Киевская', 'Чкаловская') #{('Курская', 'Чкаловская'), ('Сретенский бульвар', 'Чкаловская')}
Exemplo n.º 5
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def global_resilience(G):
    #Global resilience
    #Calculate the size of the reachable nodes set for each node in the graph G
    h_max = len(G)

    # for each node n in Graph G calculate the h-hop environment h_ball, then number of nodes n_cnt in h_ball, and the local Resilience Rih
    # declare lists for the average number of nodes n_global and average resilience R_global in each h-hop environment
    n_global = list()
    R_global = list()
    for h in range(h_max):
        n_sum = 0
        Rnh_sum = 0

        for n in G:
            h_ball = nx.ego_graph(G, n, h)
            n_count = len(h_ball)
            Rih = len(nx.minimum_node_cut(h_ball))
            #Rih = len(metis.part_graph(h_ball))
            n_sum += n_count
            Rnh_sum += Rih

        # calculate average resilience for h-hop environment h
        n_global.append(n_sum / h_max)
        R_global.append(Rnh_sum / h_max)

    return n_global, R_global
Exemplo n.º 6
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def answer_twelve():

    G_sc = answer_six()
    center = nx.center(G_sc)[0]
    mynode = answer_eleven()[0]

    return len(nx.minimum_node_cut(G_sc, center, mynode))
Exemplo n.º 7
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def calc_net_connectivity(graph_cons,
                          vehs=None,
                          cut_only_fully_connected=True):
    """Calculates the network connectivity (relative size of the biggest connected cluster)"""

    time_start = utils.debug(None, 'Finding biggest cluster')

    # Find biggest cluster
    count_veh = graph_cons.order()
    clusters = list(nx.connected_component_subgraphs(graph_cons))
    cluster_max = max(clusters, key=len)
    count_veh_max = cluster_max.order()
    net_connectivity = count_veh_max / count_veh
    if vehs is not None:
        cluster_nodes = cluster_max.nodes()
        vehs.add_key('cluster_max', cluster_nodes)
        not_cluster_max_nodes = np.arange(
            count_veh)[~np.in1d(np.arange(count_veh), cluster_nodes)]
        vehs.add_key('not_cluster_max', not_cluster_max_nodes)

    # Find the minimum node cut
    count_cluster = len(clusters)
    if count_cluster == 1 or not cut_only_fully_connected:
        min_node_cut = nx.minimum_node_cut(cluster_max)
    else:
        min_node_cut = None

    result = NetworkConnectivity(net_connectivity=net_connectivity,
                                 min_node_cut=min_node_cut,
                                 count_cluster=count_cluster)
    utils.debug(time_start)

    return result
Exemplo n.º 8
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def answer_twelve():
    G = answer_six()

    return len(
        nx.minimum_node_cut(G,
                            list(answer_ten())[0],
                            answer_eleven()[0]))
def find_which_nodes_and_edges_to_remove(G, n1, n2):
    a = nx.node_connectivity(G, n1, n2)
    b = nx.minimum_node_cut(G, n1, n2)
    c = nx.edge_connectivity(G, n1, n2)
    d = nx.minimum_edge_cut(G, n1, n2)
    print(a, b, c, d)
    return (a, b, c, d)
Exemplo n.º 10
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def test_node_cutset_random_graphs():
    for i in range(5):
        G = nx.fast_gnp_random_graph(50,0.2)
        cutset = nx.minimum_node_cut(G)
        assert_equal(nx.node_connectivity(G), len(cutset))
        G.remove_nodes_from(cutset)
        assert_false(nx.is_connected(G))
Exemplo n.º 11
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def test_white_harary_paper():
    # Figure 1b white and harary (2001)
    # http://eclectic.ss.uci.edu/~drwhite/sm-w23.PDF
    # A graph with high adhesion (edge connectivity) and low cohesion
    # (node connectivity)
    G = nx.disjoint_union(nx.complete_graph(4), nx.complete_graph(4))
    G.remove_node(7)
    for i in range(4,7):
        G.add_edge(0,i)
    G = nx.disjoint_union(G, nx.complete_graph(4))
    G.remove_node(G.order()-1)
    for i in range(7,10):
        G.add_edge(0,i)
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        # edge cuts
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        assert_equal(3, len(edge_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
        # node cuts
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert_equal(set([0]), node_cut, msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
Exemplo n.º 12
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def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for i in range(5):
        G = next(Ggen)
        cut = nx.minimum_node_cut(G)
        assert_true(len(cut) == 1)
        assert_true(cut.pop() in set(nx.articulation_points(G)))
def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for i in range(5):
        G = next(Ggen)
        cut = nx.minimum_node_cut(G)
        assert_true(len(cut) == 1)
        assert_true(cut.pop() in set(nx.articulation_points(G)))
Exemplo n.º 14
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def answer_twelve():

    # Your Code Here
    G_sc = answer_six()
    center = nx.center(G_sc)[0]
    node = answer_eleven()[0]
    return len(nx.minimum_node_cut(G_sc, center, node))
Exemplo n.º 15
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def test_node_cutset_random_graphs():
    for i in range(5):
        G = nx.fast_gnp_random_graph(50, 0.2)
        cutset = nx.minimum_node_cut(G)
        assert_equal(nx.node_connectivity(G), len(cutset))
        G.remove_nodes_from(cutset)
        assert_false(nx.is_connected(G))
Exemplo n.º 16
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	def merge(self,minN):
		
		import numpy as np
		merged=[]
		merged_cliq=[]
		while len(DiGraph.nodes(self)):
			#print(len(self.nodes()))
			contcmp,ct_cliq=self.splitG(minN)

			if not DiGraph.nodes(self):
				break
			merged=merged+contcmp 
			merged_cliq=merged_cliq+ct_cliq

			try:
				#print("point1")
				cut_nodes=minimum_node_cut(self)

				#print("point2")
			except:
				nodes=DiGraph.nodes(self)
				index=np.random.randint(len(nodes))
				cut_nodes=[nodes[index]]

			for node in cut_nodes:
				DiGraph.remove_node(self,node)

		self.topics=merged
		self.topic_cliq=merged_cliq
Exemplo n.º 17
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def graphDisjointPath(NG, group1, group2, operation):

    nmbOutputs = len(NG)
    nmbOutputs2 = len(NG[0])

    #operation depicts if the minimum disconnected set should be located (operation==0) or the disjoint path (operation==1)

    #below function will read through the mat file and try to find how many modules their are

    #using the network functions create a direction graph (nodes with a connection with a direction so connection 1 to 2 has a direction and is not the same as 2 to 1)
    plot = nx.DiGraph()
    plot.add_nodes_from(range(nmbOutputs))

    for x in range(nmbOutputs):
        for y in range(nmbOutputs2):
            if (NG[x][y] == 1):
                plot.add_edge(y, x)

    plot.add_node(nmbOutputs)
    plot.add_node(nmbOutputs + 1)
    for x in group1:
        plot.add_edge(nmbOutputs, x[1].nmb - 1)

    for x in group2:
        plot.add_edge(x[1].nmb - 1, nmbOutputs + 1)

    if (operation):
        result = list(nx.node_disjoint_paths(plot, nmbOutputs, nmbOutputs + 1))
    else:
        result = list(nx.minimum_node_cut(plot, nmbOutputs, nmbOutputs + 1))

    return result
Exemplo n.º 18
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def test_white_harary_paper():
    # Figure 1b white and harary (2001)
    # http://eclectic.ss.uci.edu/~drwhite/sm-w23.PDF
    # A graph with high adhesion (edge connectivity) and low cohesion
    # (node connectivity)
    G = nx.disjoint_union(nx.complete_graph(4), nx.complete_graph(4))
    G.remove_node(7)
    for i in range(4, 7):
        G.add_edge(0, i)
    G = nx.disjoint_union(G, nx.complete_graph(4))
    G.remove_node(G.order() - 1)
    for i in range(7, 10):
        G.add_edge(0, i)
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        errmsg = f"Assertion failed in function: {flow_func.__name__}"
        # edge cuts
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        assert 3 == len(edge_cut), errmsg
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert not nx.is_connected(H), errmsg
        # node cuts
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert {0} == node_cut, errmsg
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert not nx.is_connected(H), errmsg
Exemplo n.º 19
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def test_white_harary_paper():
    # Figure 1b white and harary (2001)
    # http://eclectic.ss.uci.edu/~drwhite/sm-w23.PDF
    # A graph with high adhesion (edge connectivity) and low cohesion
    # (node connectivity)
    G = nx.disjoint_union(nx.complete_graph(4), nx.complete_graph(4))
    G.remove_node(7)
    for i in range(4, 7):
        G.add_edge(0, i)
    G = nx.disjoint_union(G, nx.complete_graph(4))
    G.remove_node(G.order() - 1)
    for i in range(7, 10):
        G.add_edge(0, i)
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        # edge cuts
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        assert_equal(3, len(edge_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
        # node cuts
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert_equal(set([0]), node_cut, msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
Exemplo n.º 20
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def find_chamber(graph):
    """Detect chambers (rooms with a single square entrance).

    Return (entrance, chamber), where `entrance` is the node representing the
    entrance to the chamber (None if no chamber is found), and `chamber` is the
    list of nodes within the chamber (empty list if no nodes are in the chamber).

    The entrance to a chamber is a node that when removed from the graph
    will result in the graph to be split into two disconnected graphs."""
    # minimum_node_cut returns a set of nodes of minimum cardinality that
    # disconnects the graph. This means that we have a chamber if the length
    # of this set is one, i.e. there is one node that when removed disconnects
    # the graph
    cuts = nx.minimum_node_cut(graph)
    if len(cuts) > 1:
        # no chambers, yeah!
        return None, []
    entrance = cuts.pop()
    # remove the cut, i.e. put a wall on the entrance
    lgraph = nx.restricted_view(graph, [entrance], [])
    # now get the resulting subgraphs
    subgraphs = sorted(nx.connected_components(lgraph), key=len)
    # let's get the smallest subgraph: this is going to be a chamber
    # (other subgraphs are other chambers (if any) and the 'rest' of the graph
    # return a list of nodes, instead of a set
    chamber = list(subgraphs[0])
    return entrance, chamber
Exemplo n.º 21
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def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for flow_func in flow_funcs:
        for i in range(3):
            G = next(Ggen)
            cut = nx.minimum_node_cut(G, flow_func=flow_func)
            assert_true(len(cut) == 1, msg=msg.format(flow_func.__name__))
            assert_true(cut.pop() in set(nx.articulation_points(G)), msg=msg.format(flow_func.__name__))
Exemplo n.º 22
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def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for flow_func in flow_funcs:
        for i in range(3):
            G = next(Ggen)
            cut = nx.minimum_node_cut(G, flow_func=flow_func)
            assert_true(len(cut) == 1, msg=msg.format(flow_func.__name__))
            assert_true(cut.pop() in set(nx.articulation_points(G)),
                        msg=msg.format(flow_func.__name__))
Exemplo n.º 23
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def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for flow_func in flow_funcs:
        errmsg = f"Assertion failed in function: {flow_func.__name__}"
        for i in range(1):  # change 1 to 3 or more for more realizations.
            G = next(Ggen)
            cut = nx.minimum_node_cut(G, flow_func=flow_func)
            assert len(cut) == 1, errmsg
            assert cut.pop() in set(nx.articulation_points(G)), errmsg
Exemplo n.º 24
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def test_articulation_points():
    Ggen = _generate_no_biconnected()
    for flow_func in flow_funcs:
        for i in range(1):  # change 1 to 3 or more for more realizations.
            G = next(Ggen)
            cut = nx.minimum_node_cut(G, flow_func=flow_func)
            assert_true(len(cut) == 1, msg=msg % (flow_func.__name__, ))
            assert_true(cut.pop() in set(nx.articulation_points(G)),
                        msg=msg % (flow_func.__name__, ))
Exemplo n.º 25
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 def minimum_node_cut(self):
     if nx.is_connected(self.DG):
         cutset = nx.minimum_node_cut(self.DG)
         print('### information about the minimum number of nodes that disconnects the graph')
         print('the minimum number of node that if removed, ' \
               'would partition the graph into two components: ' + str(len(cutset)))
         print('the minimum node cut contains the following nodes: ' + str(cutset))
     else:
         print('Graph is not connected! No information provided for the minimum node cut.')
Exemplo n.º 26
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def local_resilience(G, h, i):
    #Local resilience
    if (h < 0) or (type(h) is not int):
        raise ValueError("h-hop environment radius is not a natural number")

    if G.has_node(i):
        return len(nx.minimum_node_cut(nx.ego_graph(G, i, h)))
        #return len(metis.part_graph(nx.ego_graph(G, i, h)))
    else:
        raise ValueError("{0} is not in given Graph".format(i))
Exemplo n.º 27
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def answer_twelve():
    nodes_to_cut = set()
    G_sc = answer_six()
    target = answer_eleven()[0]
    sources = nx.center(G_sc)
    for source in sources:
        min_nodes_to_cut = nx.minimum_node_cut(G_sc, s=source, t=target)
        nodes_to_cut.update(min_nodes_to_cut)
    n_min_nodes_to_cut = len(nodes_to_cut)
    return n_min_nodes_to_cut
Exemplo n.º 28
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def find_minimum_vertex_cut(new:bool=False,s:tuple=None,t:tuple=None):
    """
    Description: Find minimum vertex cut

    Args:
        new (bool): A variable to decide which graph to use. Default value <False>
    Returns:
        minimum_node_cut
    """
    global G
    global new_G

    if not new:
        return nx.minimum_node_cut(G)
    else:
        if s != None and t != None:
            return minimum_st_node_cut(new_G,s,t)
        return nx.minimum_node_cut(new_G)
    return None
Exemplo n.º 29
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def answer_twelve():
    # Your Code Here
    G_sc = answer_six()
    node_11 = answer_eleven()[0]
    center_nodes = nx.center(G_sc)

    no_cut_nodes = len(
        [nx.minimum_node_cut(G_sc, cn, node_11) for cn in center_nodes][0])

    return no_cut_nodes
Exemplo n.º 30
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def answer_twelve():
        
    G_sc =  answer_six()
    center_list = list(set(nx.center(G_sc)))
    my_set = set([])
    for node in center_list:
               
        my_set = my_set.union(nx.minimum_node_cut(G_sc, node, "97"))
    
    return len(my_set)
def test_node_cutset_random_graphs():
    for i in range(5):
        G = nx.fast_gnp_random_graph(50, 0.2)
        if not nx.is_connected(G):
            ccs = iter(nx.connected_components(G))
            start = next(ccs)[0]
            G.add_edges_from((start, c[0]) for c in ccs)
        cutset = nx.minimum_node_cut(G)
        assert_equal(nx.node_connectivity(G), len(cutset))
        G.remove_nodes_from(cutset)
        assert_false(nx.is_connected(G))
Exemplo n.º 32
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def test_node_cutset_random_graphs():
    for i in range(5):
        G = nx.fast_gnp_random_graph(50,0.2)
        if not nx.is_connected(G):
            ccs = iter(nx.connected_components(G))
            start = next(ccs)[0]
            G.add_edges_from( (start,c[0]) for c in ccs )
        cutset = nx.minimum_node_cut(G)
        assert_equal(nx.node_connectivity(G), len(cutset))
        G.remove_nodes_from(cutset)
        assert_false(nx.is_connected(G))
Exemplo n.º 33
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def test_node_cutset_random_graphs():
    for flow_func in flow_funcs:
        for i in range(3):
            G = nx.fast_gnp_random_graph(50, 0.25)
            if not nx.is_connected(G):
                ccs = iter(nx.connected_components(G))
                start = arbitrary_element(next(ccs))
                G.add_edges_from((start, arbitrary_element(c)) for c in ccs)
            cutset = nx.minimum_node_cut(G, flow_func=flow_func)
            assert_equal(nx.node_connectivity(G), len(cutset), msg=msg.format(flow_func.__name__))
            G.remove_nodes_from(cutset)
            assert_false(nx.is_connected(G), msg=msg.format(flow_func.__name__))
Exemplo n.º 34
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def test_node_cutset_random_graphs():
    for flow_func in flow_funcs:
        for i in range(3):
            G = nx.fast_gnp_random_graph(50, 0.25)
            if not nx.is_connected(G):
                ccs = iter(nx.connected_components(G))
                start = arbitrary_element(next(ccs))
                G.add_edges_from((start, arbitrary_element(c)) for c in ccs)
            cutset = nx.minimum_node_cut(G, flow_func=flow_func)
            assert_equal(nx.node_connectivity(G), len(cutset),
                         msg=msg.format(flow_func.__name__))
            G.remove_nodes_from(cutset)
            assert_false(nx.is_connected(G), msg=msg.format(flow_func.__name__))
def answer_twelve():
    G_sc = answer_six()
    G_sc_center = nx.center(G_sc)[0]  # only contains one node
    isolate_node = answer_eleven()[0]

    # An edge between G_sc_center and isolation_node exists.
    # There is a check for such an edge in
    # ../lib/python3.8/site-packages/networkx/algorithms/connectivity/cuts.py line 286
    # This was added in version 2.0 of networkx
    #
    # Autograder uses networkx version 1.11 which does not have this check.
    # Output accepting by autograder:  5
    return len(nx.minimum_node_cut(G_sc, G_sc_center, isolate_node))
Exemplo n.º 36
0
def test_node_cutset_random_graphs():
    for flow_func in flow_funcs:
        errmsg = f"Assertion failed in function: {flow_func.__name__}"
        for i in range(3):
            G = nx.fast_gnp_random_graph(50, 0.25, seed=42)
            if not nx.is_connected(G):
                ccs = iter(nx.connected_components(G))
                start = arbitrary_element(next(ccs))
                G.add_edges_from((start, arbitrary_element(c)) for c in ccs)
            cutset = nx.minimum_node_cut(G, flow_func=flow_func)
            assert nx.node_connectivity(G) == len(cutset), errmsg
            G.remove_nodes_from(cutset)
            assert not nx.is_connected(G), errmsg
Exemplo n.º 37
0
def test_octahedral_cutset():
    G=nx.octahedral_graph()
    # edge cuts
    edge_cut = nx.minimum_edge_cut(G)
    assert_equal(4, len(edge_cut))
    H = G.copy()
    H.remove_edges_from(edge_cut)
    assert_false(nx.is_connected(H))
    # node cuts
    node_cut = nx.minimum_node_cut(G)
    assert_equal(4,len(node_cut))
    H = G.copy()
    H.remove_nodes_from(node_cut)
    assert_false(nx.is_connected(H))
def test_octahedral_cutset():
    G = nx.octahedral_graph()
    # edge cuts
    edge_cut = nx.minimum_edge_cut(G)
    assert_equal(4, len(edge_cut))
    H = G.copy()
    H.remove_edges_from(edge_cut)
    assert_false(nx.is_connected(H))
    # node cuts
    node_cut = nx.minimum_node_cut(G)
    assert_equal(4, len(node_cut))
    H = G.copy()
    H.remove_nodes_from(node_cut)
    assert_false(nx.is_connected(H))
def answer_twelve():

    G_sc = answer_six()
    center = nx.center(G_sc)
    node = answer_eleven()[0]
    rslt = set()
    for c in center:
        tmp = nx.minimum_node_cut(G_sc, c, node)
        for i in tmp:
            if rslt is None:
                rslt = set(i)
            else:
                rslt.add(i)

    return len(rslt)
Exemplo n.º 40
0
def test_icosahedral_cutset():
    G = nx.icosahedral_graph()
    for flow_func in flow_funcs:
        kwargs = dict(flow_func=flow_func)
        # edge cuts
        edge_cut = nx.minimum_edge_cut(G, **kwargs)
        assert_equal(5, len(edge_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_edges_from(edge_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
        # node cuts
        node_cut = nx.minimum_node_cut(G, **kwargs)
        assert_equal(5, len(node_cut), msg=msg.format(flow_func.__name__))
        H = G.copy()
        H.remove_nodes_from(node_cut)
        assert_false(nx.is_connected(H), msg=msg.format(flow_func.__name__))
Exemplo n.º 41
0
 def minimum_cut(self):
     # Sometimes begin nodes may not even be in the graph!
     if self.begin_node not in self.nx_graph.nodes():
         return None
     return nx.minimum_node_cut(
         self.nx_graph, self.begin_node, self.end_node)