176 lines
6.1 KiB
Python
176 lines
6.1 KiB
Python
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#!/usr/bin/env python
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import pytest
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import networkx as nx
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from networkx import NetworkXNotImplemented
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class TestStronglyConnected:
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@classmethod
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def setup_class(cls):
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cls.gc = []
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G = nx.DiGraph()
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G.add_edges_from([(1, 2), (2, 3), (2, 8), (3, 4), (3, 7), (4, 5),
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(5, 3), (5, 6), (7, 4), (7, 6), (8, 1), (8, 7)])
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C = {frozenset([3, 4, 5, 7]), frozenset([1, 2, 8]), frozenset([6])}
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cls.gc.append((G, C))
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G = nx.DiGraph()
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G.add_edges_from([(1, 2), (1, 3), (1, 4), (4, 2), (3, 4), (2, 3)])
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C = {frozenset([2, 3, 4]), frozenset([1])}
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cls.gc.append((G, C))
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G = nx.DiGraph()
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G.add_edges_from([(1, 2), (2, 3), (3, 2), (2, 1)])
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C = {frozenset([1, 2, 3])}
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cls.gc.append((G, C))
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# Eppstein's tests
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G = nx.DiGraph({0: [1], 1: [2, 3], 2: [4, 5], 3: [4, 5], 4: [6], 5: [], 6: []})
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C = {
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frozenset([0]),
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frozenset([1]),
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frozenset([2]),
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frozenset([3]),
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frozenset([4]),
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frozenset([5]),
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frozenset([6]),
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}
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cls.gc.append((G, C))
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G = nx.DiGraph({0: [1], 1: [2, 3, 4], 2: [0, 3], 3: [4], 4: [3]})
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C = {frozenset([0, 1, 2]), frozenset([3, 4])}
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cls.gc.append((G, C))
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def test_tarjan(self):
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scc = nx.strongly_connected_components
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for G, C in self.gc:
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assert {frozenset(g) for g in scc(G)} == C
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def test_tarjan_recursive(self):
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scc = nx.strongly_connected_components_recursive
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for G, C in self.gc:
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assert {frozenset(g) for g in scc(G)} == C
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def test_kosaraju(self):
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scc = nx.kosaraju_strongly_connected_components
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for G, C in self.gc:
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assert {frozenset(g) for g in scc(G)} == C
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def test_number_strongly_connected_components(self):
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ncc = nx.number_strongly_connected_components
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for G, C in self.gc:
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assert ncc(G) == len(C)
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def test_is_strongly_connected(self):
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for G, C in self.gc:
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if len(C) == 1:
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assert nx.is_strongly_connected(G)
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else:
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assert not nx.is_strongly_connected(G)
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def test_contract_scc1(self):
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G = nx.DiGraph()
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G.add_edges_from([
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(1, 2), (2, 3), (2, 11), (2, 12), (3, 4), (4, 3), (4, 5), (5, 6),
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(6, 5), (6, 7), (7, 8), (7, 9), (7, 10), (8, 9), (9, 7), (10, 6),
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(11, 2), (11, 4), (11, 6), (12, 6), (12, 11),
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])
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scc = list(nx.strongly_connected_components(G))
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cG = nx.condensation(G, scc)
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# DAG
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assert nx.is_directed_acyclic_graph(cG)
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# nodes
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assert sorted(cG.nodes()) == [0, 1, 2, 3]
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# edges
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mapping = {}
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for i, component in enumerate(scc):
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for n in component:
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mapping[n] = i
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edge = (mapping[2], mapping[3])
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assert cG.has_edge(*edge)
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edge = (mapping[2], mapping[5])
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assert cG.has_edge(*edge)
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edge = (mapping[3], mapping[5])
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assert cG.has_edge(*edge)
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def test_contract_scc_isolate(self):
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# Bug found and fixed in [1687].
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G = nx.DiGraph()
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G.add_edge(1, 2)
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G.add_edge(2, 1)
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scc = list(nx.strongly_connected_components(G))
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cG = nx.condensation(G, scc)
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assert list(cG.nodes()) == [0]
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assert list(cG.edges()) == []
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def test_contract_scc_edge(self):
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G = nx.DiGraph()
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G.add_edge(1, 2)
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G.add_edge(2, 1)
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G.add_edge(2, 3)
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G.add_edge(3, 4)
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G.add_edge(4, 3)
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scc = list(nx.strongly_connected_components(G))
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cG = nx.condensation(G, scc)
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assert sorted(cG.nodes()) == [0, 1]
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if 1 in scc[0]:
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edge = (0, 1)
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else:
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edge = (1, 0)
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assert list(cG.edges()) == [edge]
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def test_condensation_mapping_and_members(self):
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G, C = self.gc[1]
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C = sorted(C, key=len, reverse=True)
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cG = nx.condensation(G)
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mapping = cG.graph['mapping']
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assert all(n in G for n in mapping)
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assert all(0 == cN for n, cN in mapping.items() if n in C[0])
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assert all(1 == cN for n, cN in mapping.items() if n in C[1])
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for n, d in cG.nodes(data=True):
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assert set(C[n]) == cG.nodes[n]['members']
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def test_null_graph(self):
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G = nx.DiGraph()
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assert list(nx.strongly_connected_components(G)) == []
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assert list(nx.kosaraju_strongly_connected_components(G)) == []
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assert list(nx.strongly_connected_components_recursive(G)) == []
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assert len(nx.condensation(G)) == 0
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pytest.raises(nx.NetworkXPointlessConcept, nx.is_strongly_connected, nx.DiGraph())
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def test_connected_raise(self):
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G = nx.Graph()
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pytest.raises(NetworkXNotImplemented, nx.strongly_connected_components, G)
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pytest.raises(NetworkXNotImplemented, nx.kosaraju_strongly_connected_components, G)
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pytest.raises(NetworkXNotImplemented, nx.strongly_connected_components_recursive, G)
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pytest.raises(NetworkXNotImplemented, nx.is_strongly_connected, G)
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pytest.raises(nx.NetworkXPointlessConcept, nx.is_strongly_connected, nx.DiGraph())
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pytest.raises(NetworkXNotImplemented, nx.condensation, G)
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# Commented out due to variability on Travis-CI hardware/operating systems
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# def test_linear_time(self):
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# # See Issue #2831
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# count = 100 # base case
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# dg = nx.DiGraph()
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# dg.add_nodes_from([0, 1])
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# for i in range(2, count):
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# dg.add_node(i)
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# dg.add_edge(i, 1)
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# dg.add_edge(0, i)
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# t = time.time()
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# ret = tuple(nx.strongly_connected_components(dg))
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# dt = time.time() - t
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#
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# count = 200
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# dg = nx.DiGraph()
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# dg.add_nodes_from([0, 1])
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# for i in range(2, count):
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# dg.add_node(i)
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# dg.add_edge(i, 1)
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# dg.add_edge(0, i)
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# t = time.time()
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# ret = tuple(nx.strongly_connected_components(dg))
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# dt2 = time.time() - t
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# assert_less(dt2, dt * 2.3) # should be 2 times longer for this graph
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