def test_general_k_edge_subgraph_quick_return():
# tests quick return optimization
G = nx.Graph()
G.add_node(0)
subgraphs = list(general_k_edge_subgraphs(G, k=1))
assert len(subgraphs) == 1
for subgraph in subgraphs:
assert subgraph.number_of_nodes() == 1
G.add_node(1)
subgraphs = list(general_k_edge_subgraphs(G, k=1))
assert len(subgraphs) == 2
for subgraph in subgraphs:
assert subgraph.number_of_nodes() == 1
def test_general_k_edge_subgraph_quick_return():
# tests quick return optimization
G = nx.Graph()
G.add_node(0)
subgraphs = list(general_k_edge_subgraphs(G, k=1))
assert_equal(len(subgraphs), 1)
for subgraph in subgraphs:
assert_equal(subgraph.number_of_nodes(), 1)
G.add_node(1)
subgraphs = list(general_k_edge_subgraphs(G, k=1))
assert_equal(len(subgraphs), 2)
for subgraph in subgraphs:
assert_equal(subgraph.number_of_nodes(), 1)
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 _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_zero_k_exception():
G = nx.Graph()
# functions that return generators error immediately
pytest.raises(ValueError, nx.k_edge_components, G, k=0)
pytest.raises(ValueError, nx.k_edge_subgraphs, G, k=0)
# actual generators only error when you get the first item
aux_graph = EdgeComponentAuxGraph.construct(G)
pytest.raises(ValueError, list, aux_graph.k_edge_components(k=0))
pytest.raises(ValueError, list, aux_graph.k_edge_subgraphs(k=0))
pytest.raises(ValueError, list, general_k_edge_subgraphs(G, k=0))
def test_zero_k_exception():
G = nx.Graph()
# functions that return generators error immediately
assert_raises(ValueError, nx.k_edge_components, G, k=0)
assert_raises(ValueError, nx.k_edge_subgraphs, G, k=0)
# actual generators only error when you get the first item
aux_graph = EdgeComponentAuxGraph.construct(G)
assert_raises(ValueError, list, aux_graph.k_edge_components(k=0))
assert_raises(ValueError, list, aux_graph.k_edge_subgraphs(k=0))
assert_raises(ValueError, list, general_k_edge_subgraphs(G, k=0))
