def test_non_symmetric_min_unsat(self):
G = nx.complete_graph(4)
T = nx.empty_graph(4)
edges = list(combinations(G.nodes(),2))
T.add_edges_from(edges[1:])
F = SubgraphFormula(G,[T])
self.assertUNSAT(F)
def test_no_templates(self):
"""No templates graphs should generate an empty fomula
"""
dimacs = """\
p cnf 0 0
"""
G = nx.complete_graph(4)
F = SubgraphFormula(G,[])
self.assertCnfEqualsDimacs(F,dimacs)
def test_parameters(self):
for base in range(2,5):
for template in range(2,5):
parameters = ["cnfgen","-q","subgraph",
"--complete", base,
"--completeT" , template]
G = nx.complete_graph(base)
T = nx.complete_graph(template)
F = SubgraphFormula(G,[T])
self.checkFormula(sys.stdin,F, parameters)
parameters = ["cnfgen","-q","subgraph",
"--complete", base,
"--emptyT" , template]
G = nx.complete_graph(base)
T = nx.empty_graph(template)
F = SubgraphFormula(G,[T])
self.checkFormula(sys.stdin,F, parameters)
def test_non_symmetric_input_right(self):
"""Symmetric encoding on non-symmetric graph
The formula in this test uses the NON symmetric encoding for
a non symmetric graph. This causes the formula to be
satisfiable, as it should be.
"""
G = readGraph(sio(example1),"simple",file_format="kthlist")
T = readGraph(sio(example1alt),"simple",file_format="kthlist")
F = SubgraphFormula(G,[T])
self.assertSAT(F)
def test_non_symmetric_input_wrong(self):
"""Symmetric encoding on non-symmetric graph
The formula in this test uses the symmetric encoding for a non
symmetric graph. This causes the formula to be unsatisfiable,
even if it should be SAT.
"""
G = readGraph(sio(example1),"simple",file_format="kthlist")
T = readGraph(sio(example1alt),"simple",file_format="kthlist")
F = SubgraphFormula(G,[T],symmetric=True) # This should cause the wrong answer
self.assertUNSAT(F)
def test_non_symmetric_clause_generator(self):
"""Check a tricky case in the implementation
If the formula uses non symmetric encoding for the subset of
vertices, then also the part of the formula about matching the
edges requires non symmetric encoding.
This checks that both parts are implemented correctly.
"""
G = nx.complete_graph(4)
T = nx.empty_graph(4)
F = SubgraphFormula(G,[T])
self.assertUNSAT(F)
def test_symmetric_min_unsat(self):
G = nx.empty_graph(4)
G.add_edge(0,1)
T = nx.empty_graph(4)
F = SubgraphFormula(G,[T])
self.assertUNSAT(F)