def test_up_unsat(): # (x1|~x2|x3)&x2&(~x1|x3)&(x2|~x3) --> UNSAT x1_var = Variable('x1') x2_var = Variable('x2') x3_var = Variable('x3') x1 = Literal(x1_var, negated=False) not_x1 = Literal(x1_var, negated=True) x2 = Literal(x2_var, negated=False) not_x2 = Literal(x2_var, negated=True) x3 = Literal(x3_var, negated=False) not_x3 = Literal(x3_var, negated=True) clauses = [[x1, not_x2, x3], [x2], [not_x1, x3], [not_x2, not_x3]] # literal_to_clauses = {x1: {0}, not_x1: {2}, not_x2: {0, 3}, x2: {1}, x3: {0, 2}, not_x3: {3}} cnf = CnfFormula(clauses) cnf = preprocess(cnf) dpll = DPLL(cnf) actual_cnf = dpll.unit_propagation() assert actual_cnf is None assert not dpll.get_full_assignment()[x3_var] assert dpll.get_full_assignment()[x2_var]
def test_up_simple(): # (x1|~x2|x3)&x2&(~x1|x3) --> (x1|x3) & (~x1|x3) x1_var = Variable('x1') x2_var = Variable('x2') x3_var = Variable('x3') x1 = Literal(x1_var, negated=False) not_x1 = Literal(x1_var, negated=True) x2 = Literal(x2_var, negated=False) not_x2 = Literal(x2_var, negated=True) x3 = Literal(x3_var, negated=False) clauses = [[x1, not_x2, x3], [x2], [not_x1, x3]] cnf = CnfFormula(clauses) cnf = preprocess(cnf) dpll = DPLL(cnf) actual_cnf = dpll.unit_propagation() expected_cnf = [[x1, not_x2, x3], [not_x1, x3]] assert dpll.get_full_assignment()[x2_var] actual_cnf_real = [cl for cl in actual_cnf.clauses if cl != []] assert actual_cnf_real == expected_cnf, dpll.get_full_assignment()