def test_set_value_for_literal_sets_value(self):
mapping = {self.variable: False}
v = Valuation(mapping)
l = Literal(self.variable)
v.set_value_for_literal(l, True)
self.assertEqual(True, v.get_value_for_literal(l))
def test_create_offspring_creates_second_child_correctly_after_crossover_point(self):
variables = self.rand_maxsat.variables
crossover_index = int(len(variables) / 2)
valuation1 = Valuation.init_random_from_variables(variables)
valuation2 = Valuation.init_random_from_variables(variables)
offspring = self.rand_ga.create_offspring(valuation1, valuation2, crossover_index=crossover_index)
child2 = offspring[1]
self.assertTrue(
all(child2.get_value_for_variable(v) == valuation1.get_value_for_variable(v)
for v in variables[crossover_index + 1:])
)
def generate_population(self):
""" Generates a population of random candidate solutions.
:return: list of 'self.population_size' amount of Valuation instances
"""
population = []
for i in range(self.population_size):
population.append(Valuation.init_random_from_variables(self.maxsat.variables))
return population
def test_get_candidate_fitness_returns_half(self):
v1 = Variable('a')
c1 = Clause([Literal(v1, positive=True)])
c2 = Clause([Literal(v1, positive=False)])
maxsat = MAXSAT([v1], [c1, c2])
valuation = Valuation.init_random_from_variables([v1])
ga = GA(maxsat)
self.assertEqual(0.5, ga.get_candidate_fitness(valuation))
def test_change_random_variable_changes_exactly_one_variable(self):
v = Valuation.init_random_from_variables(self.variables)
original_valuation = v.valuation.copy()
v.change_value_for_random_variable()
new_valuation = v.valuation
changed_variables = [
variable for variable in self.variables
if not original_valuation.get(variable) == new_valuation.get(variable)
]
self.assertEqual(1, len(changed_variables))
def test_create_offspring_creates_two_children(self):
valuation1 = Valuation.init_random_from_variables(self.rand_maxsat.variables)
valuation2 = Valuation.init_random_from_variables(self.rand_maxsat.variables)
offspring = self.rand_ga.create_offspring(valuation1, valuation2)
self.assertEqual(2, len(offspring))
def test_init_random_creates_valuation_with_bools(self):
v = Valuation.init_random_from_variables(self.variables)
self.assertTrue(all(isinstance(k, bool) for k in v.valuation.values()))
def test_init_random_creates_valuation_of_correct_length(self):
v = Valuation.init_random_from_variables(self.variables)
self.assertEqual(len(self.variables), len(v.valuation))
def test_get_value_for_negated_literal_returns_correct_value(self):
value = False
mapping = {self.variable: value}
v = Valuation(mapping)
self.assertEqual(not value, v.get_value_for_literal(Literal(self.variable, positive=False)))
def test_set_value_for_variable_sets_value(self):
mapping = {self.variable: False}
v = Valuation(mapping)
v.set_value_for_variable(self.variable, True)
self.assertEqual(True, v.get_value_for_variable(self.variable))
def test_get_value_for_variable_returns_correct_value(self):
value = False
mapping = {self.variable: value}
v = Valuation(mapping)
self.assertEqual(value, v.get_value_for_variable(self.variable))