def test_power(self, problem):
ctx = ProblemContext(problem)
r = McCormickExpressionRelaxation()
power = problem.constraint('power').root_expr
ctx.set_polynomiality(power, PolynomialDegree(2))
assert r.can_relax(problem, power, ctx)
def test_trilinear_terms(self, problem):
ctx = ProblemContext(problem)
r = McCormickExpressionRelaxation()
trilinear = problem.constraint('trilinear').root_expr
ctx.set_polynomiality(trilinear, PolynomialDegree(3))
assert not r.can_relax(problem, trilinear, ctx)
def test_bilinear_terms(self, problem):
r = McCormickExpressionRelaxation()
ctx = ProblemContext(problem)
bilinear = problem.constraint('bilinear').root_expr
assert r.can_relax(problem, bilinear, ctx)
result = r.relax(problem, bilinear, ctx)
self._check_constraints(result)
assert result.expression.expression_type == ExpressionType.Linear
assert len(result.expression.children) == 1
aux_var = result.expression.children[0]
assert aux_var.is_auxiliary
def test_bilinear_with_coef_2(self, problem):
ctx = ProblemContext(problem)
r = McCormickExpressionRelaxation()
bilinear = problem.constraint('bilinear_coef_2').root_expr
ctx.set_polynomiality(bilinear, PolynomialDegree(2))
assert r.can_relax(problem, bilinear, ctx)
result = r.relax(problem, bilinear, ctx)
self._check_constraints(result)
expr = result.expression
assert expr.expression_type == ExpressionType.Linear
assert np.allclose(expr.coefficient(expr.children[0]), np.array([6.0]))
def test_bilinear_sum(self, problem):
ctx = ProblemContext(problem)
r = McCormickExpressionRelaxation()
bilinear = problem.constraint('bilinear_sum').root_expr
ctx.set_polynomiality(bilinear, PolynomialDegree(2))
assert r.can_relax(problem, bilinear, ctx)
result = r.relax(problem, bilinear, ctx)
assert len(result.constraints) == 12
expr = result.expression
assert expr.expression_type == ExpressionType.Linear
assert len(expr.children) == 3