def test_not_implemented():
G = nx.MultiGraph()
pytest.raises(nx.NetworkXNotImplemented, EdgeComponentAuxGraph.construct,
G)
pytest.raises(nx.NetworkXNotImplemented, nx.k_edge_components, G, k=2)
pytest.raises(nx.NetworkXNotImplemented, nx.k_edge_subgraphs, G, k=2)
with pytest.raises(nx.NetworkXNotImplemented):
next(bridge_components(G))
with pytest.raises(nx.NetworkXNotImplemented):
next(bridge_components(nx.DiGraph()))
def _check_edge_connectivity(G):
"""
Helper - generates all k-edge-components using the aux graph. Checks the
both local and subgraph edge connectivity of each cc. Also checks that
alternate methods of computing the k-edge-ccs generate the same result.
"""
# Construct the auxillary graph that can be used to make each k-cc or k-sub
aux_graph = EdgeComponentAuxGraph.construct(G)
# memoize the local connectivity in this graph
memo = {}
for k in it.count(1):
# Test "local" k-edge-components and k-edge-subgraphs
ccs_local = fset(aux_graph.k_edge_components(k))
ccs_subgraph = fset(aux_graph.k_edge_subgraphs(k))
# Check connectivity properties that should be garuenteed by the
# algorithms.
_assert_local_cc_edge_connectivity(G, ccs_local, k, memo)
_assert_subgraph_edge_connectivity(G, ccs_subgraph, k)
if k == 1 or k == 2 and not G.is_directed():
assert_equal(
ccs_local, ccs_subgraph,
'Subgraphs and components should be the same '
'when k == 1 or (k == 2 and not G.directed())')
if G.is_directed():
# Test special case methods are the same as the aux graph
if k == 1:
alt_sccs = fset(nx.strongly_connected_components(G))
assert_equal(alt_sccs, ccs_local, 'k=1 failed alt')
assert_equal(alt_sccs, ccs_subgraph, 'k=1 failed alt')
else:
# Test special case methods are the same as the aux graph
if k == 1:
alt_ccs = fset(nx.connected_components(G))
assert_equal(alt_ccs, ccs_local, 'k=1 failed alt')
assert_equal(alt_ccs, ccs_subgraph, 'k=1 failed alt')
elif k == 2:
alt_bridge_ccs = fset(bridge_components(G))
assert_equal(alt_bridge_ccs, ccs_local, 'k=2 failed alt')
assert_equal(alt_bridge_ccs, ccs_subgraph, 'k=2 failed alt')
# if new methods for k == 3 or k == 4 are implemented add them here
# Check the general subgraph method works by itself
alt_subgraph_ccs = fset(
[set(C.nodes()) for C in general_k_edge_subgraphs(G, k=k)])
assert_equal(alt_subgraph_ccs, ccs_subgraph,
'alt subgraph method failed')
# Stop once k is larger than all special case methods
# and we cannot break down ccs any further.
if k > 2 and all(len(cc) == 1 for cc in ccs_local):
break
def test_bridge_cc():
# define 2-connected components and bridges
cc2 = [(1, 2, 4, 3, 1, 4), (8, 9, 10, 8), (11, 12, 13, 11)]
bridges = [(4, 8), (3, 5), (20, 21), (22, 23, 24)]
G = nx.Graph(it.chain(*(pairwise(path) for path in cc2 + bridges)))
bridge_ccs = fset(bridge_components(G))
target_ccs = fset([{1, 2, 3, 4}, {5}, {8, 9, 10}, {11, 12, 13}, {20}, {21},
{22}, {23}, {24}])
assert bridge_ccs == target_ccs
_check_edge_connectivity(G)
def _check_edge_connectivity(G):
"""
Helper - generates all k-edge-components using the aux graph. Checks the
both local and subgraph edge connectivity of each cc. Also checks that
alternate methods of computing the k-edge-ccs generate the same result.
"""
# Construct the auxiliary graph that can be used to make each k-cc or k-sub
aux_graph = EdgeComponentAuxGraph.construct(G)
# memoize the local connectivity in this graph
memo = {}
for k in it.count(1):
# Test "local" k-edge-components and k-edge-subgraphs
ccs_local = fset(aux_graph.k_edge_components(k))
ccs_subgraph = fset(aux_graph.k_edge_subgraphs(k))
# Check connectivity properties that should be garuenteed by the
# algorithms.
_assert_local_cc_edge_connectivity(G, ccs_local, k, memo)
_assert_subgraph_edge_connectivity(G, ccs_subgraph, k)
if k == 1 or k == 2 and not G.is_directed():
assert_equal(ccs_local, ccs_subgraph,
'Subgraphs and components should be the same '
'when k == 1 or (k == 2 and not G.directed())')
if G.is_directed():
# Test special case methods are the same as the aux graph
if k == 1:
alt_sccs = fset(nx.strongly_connected_components(G))
assert_equal(alt_sccs, ccs_local, 'k=1 failed alt')
assert_equal(alt_sccs, ccs_subgraph, 'k=1 failed alt')
else:
# Test special case methods are the same as the aux graph
if k == 1:
alt_ccs = fset(nx.connected_components(G))
assert_equal(alt_ccs, ccs_local, 'k=1 failed alt')
assert_equal(alt_ccs, ccs_subgraph, 'k=1 failed alt')
elif k == 2:
alt_bridge_ccs = fset(bridge_components(G))
assert_equal(alt_bridge_ccs, ccs_local, 'k=2 failed alt')
assert_equal(alt_bridge_ccs, ccs_subgraph, 'k=2 failed alt')
# if new methods for k == 3 or k == 4 are implemented add them here
# Check the general subgraph method works by itself
alt_subgraph_ccs = fset([set(C.nodes()) for C in
general_k_edge_subgraphs(G, k=k)])
assert_equal(alt_subgraph_ccs, ccs_subgraph,
'alt subgraph method failed')
# Stop once k is larger than all special case methods
# and we cannot break down ccs any further.
if k > 2 and all(len(cc) == 1 for cc in ccs_local):
break
def test_bridge_cc():
# define 2-connected components and bridges
cc2 = [(1, 2, 4, 3, 1, 4), (8, 9, 10, 8), (11, 12, 13, 11)]
bridges = [(4, 8), (3, 5), (20, 21), (22, 23, 24)]
G = nx.Graph(it.chain(*(pairwise(path) for path in cc2 + bridges)))
bridge_ccs = fset(bridge_components(G))
target_ccs = fset([
{1, 2, 3, 4}, {5}, {8, 9, 10}, {11, 12, 13}, {20},
{21}, {22}, {23}, {24}
])
assert_equal(bridge_ccs, target_ccs)
_check_edge_connectivity(G)
def test_bridge_cc():
# define 2-connected components and bridges
cc2 = [(1, 2, 4, 3, 1, 4), (8, 9, 10, 8), (11, 12, 13, 11)]
bridges = [(4, 8), (3, 5), (20, 21), (22, 23, 24)]
G = nx.Graph(it.chain(*(pairwise(path) for path in cc2 + bridges)))
bridge_ccs = fset(bridge_components(G))
target_ccs = fset([
set([1, 2, 3, 4]), set([5]), set([8, 9, 10]), set([11, 12, 13]), set([20]),
set([21]), set([22]), set([23]), set([24])
])
assert_equal(bridge_ccs, target_ccs)
_check_edge_connectivity(G)
