def test_sub1(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available')
x_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var(bounds=(xl, xu))
m.y = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=m.x - m.y, lower=cl, upper=cu))
self.tightener(m)
x = np.linspace(pyo.value(m.x.lb), pyo.value(m.x.ub), 100)
z = np.linspace(pyo.value(m.c.lower), pyo.value(m.c.upper),
100)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
for _x in x:
_y = _x - z
self.assertTrue(np.all(yl <= _y))
self.assertTrue(np.all(yu >= _y))
def test_sub2(self):
x_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var(bounds=(xl, xu))
m.y = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=m.y - m.x, lower=cl, upper=cu))
fbbt(m)
x = np.linspace(pyo.value(m.x.lb), pyo.value(m.x.ub), 100)
z = np.linspace(pyo.value(m.c.lower), pyo.value(m.c.upper),
100)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
for _x in x:
_y = z + _x
self.assertTrue(np.all(yl <= _y))
self.assertTrue(np.all(yu >= _y))
def test_pow(self):
x_bounds = [(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)), (0, 0)]
y_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)),
(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), 0),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0))]
for xl, xu in x_bounds:
for yl, yu in y_bounds:
zl, zu = interval.power(xl, xu, yl, yu)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
x_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0)),
(np.random.uniform(-5, -2), 0)]
y_bounds = list(range(-4, 4))
for xl, xu in x_bounds:
for yl in y_bounds:
yu = yl
zl, zu = interval.power(xl, xu, yl, yu)
x = np.linspace(xl, xu, 100, endpoint=False)
y = yl
_z = x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_pow(self):
x_bounds = [(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)), (0, 0)]
y_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)),
(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), 0),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0))]
for xl, xu in x_bounds:
for yl, yu in y_bounds:
zl, zu = interval.power(xl, xu, yl, yu, feasibility_tol=1e-8)
if xl == 0 and xu == 0 and yu < 0:
self.assertEqual(zl, -interval.inf)
self.assertEqual(zu, interval.inf)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
x_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0)),
(np.random.uniform(-5, -2), 0)]
y_bounds = list(range(-4, 4))
for xl, xu in x_bounds:
for yl in y_bounds:
yu = yl
zl, zu = interval.power(xl, xu, yl, yu, feasibility_tol=1e-8)
x = np.linspace(xl, xu, 100, endpoint=False)
y = yl
_z = x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_log10(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available')
c_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=pyo.log10(m.x), lower=cl, upper=cu))
self.tightener(m)
z = np.linspace(pyo.value(m.c.lower), pyo.value(m.c.upper), 100)
if m.x.lb is None:
xl = -np.inf
else:
xl = pyo.value(m.x.lb)
if m.x.ub is None:
xu = np.inf
else:
xu = pyo.value(m.x.ub)
x = 10**z
print(xl, xu, cl, cu)
print(x)
self.assertTrue(np.all(xl <= x))
self.assertTrue(np.all(xu >= x))
def test_pow2(self):
x_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (0.5, 2.8), (0, 2.8), (1, 2.8), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pe.Block(concrete=True)
m.x = pe.Var(bounds=(xl, xu))
m.y = pe.Var()
m.c = pe.Constraint(
expr=pe.inequality(body=m.y**m.x, lower=cl, upper=cu))
fbbt(m)
x = np.linspace(pe.value(m.x.lb) + 1e-6,
pe.value(m.x.ub),
100,
endpoint=False)
z = np.linspace(pe.value(m.c.lower) + 1e-6,
pe.value(m.c.upper),
100,
endpoint=False)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
for _x in x:
_y = np.exp(np.log(abs(z)) / _x)
self.assertTrue(np.all(yl <= _y))
self.assertTrue(np.all(yu >= _y))
def test_pow2(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available')
x_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (0.5, 2.8), (0, 2.8), (1, 2.8), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var(bounds=(xl, xu))
m.y = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=m.y**m.x, lower=cl, upper=cu))
self.tightener(m)
x = np.linspace(pyo.value(m.x.lb) + 1e-6,
pyo.value(m.x.ub),
100,
endpoint=False)
z = np.linspace(pyo.value(m.c.lower) + 1e-6,
pyo.value(m.c.upper),
100,
endpoint=False)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
y = np.exp(np.split(np.log(np.abs(z)), len(z)) / x)
self.assertTrue(np.all(yl <= y))
self.assertTrue(np.all(yu >= y))
def test_exp(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available')
c_bounds = [(-2.5, 2.8), (0.5, 2.8), (0, 2.8), (1, 2.8), (0.5, 1)]
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=pyo.exp(m.x), lower=cl, upper=cu))
self.tightener(m)
if pyo.value(m.c.lower) <= 0:
_cl = 1e-6
else:
_cl = pyo.value(m.c.lower)
z = np.linspace(_cl, pyo.value(m.c.upper), 100)
if m.x.lb is None:
xl = -np.inf
else:
xl = pyo.value(m.x.lb)
if m.x.ub is None:
xu = np.inf
else:
xu = pyo.value(m.x.ub)
x = np.log(z)
self.assertTrue(np.all(xl <= x))
self.assertTrue(np.all(xu >= x))
def test_add(self):
x_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var(bounds=(xl, xu))
m.y = pyo.Var()
m.p = pyo.Param(mutable=True)
m.p.value = 1
m.c = pyo.Constraint(expr=pyo.inequality(
body=m.x + m.y + (m.p + 1), lower=cl, upper=cu))
new_bounds = fbbt(m)
self.assertEqual(new_bounds[m.x],
(pyo.value(m.x.lb), pyo.value(m.x.ub)))
self.assertEqual(new_bounds[m.y],
(pyo.value(m.y.lb), pyo.value(m.y.ub)))
x = np.linspace(pyo.value(m.x.lb), pyo.value(m.x.ub), 100)
z = np.linspace(pyo.value(m.c.lower), pyo.value(m.c.upper),
100)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
for _x in x:
_y = z - _x - m.p.value - 1
self.assertTrue(np.all(yl <= _y))
self.assertTrue(np.all(yu >= _y))
def test_pow1(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available')
x_bounds = [(0, 2.8), (0.5, 2.8), (1, 2.8), (0.5, 1)]
c_bounds = [(-2.5, 2.8), (0.5, 2.8), (-2.5, 0), (0, 2.8), (1, 2.8), (0.5, 1)]
for xl, xu in x_bounds:
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var(bounds=(xl, xu))
m.y = pyo.Var()
m.c = pyo.Constraint(expr=pyo.inequality(body=m.x**m.y, lower=cl, upper=cu))
if xl > 0 and cu <= 0:
with self.assertRaises(InfeasibleConstraintException):
self.tightener(m)
else:
self.tightener(m)
x = np.linspace(pyo.value(m.x.lb) + 1e-6, pyo.value(m.x.ub), 100, endpoint=False)
z = np.linspace(pyo.value(m.c.lower) + 1e-6, pyo.value(m.c.upper), 100, endpoint=False)
if m.y.lb is None:
yl = -np.inf
else:
yl = m.y.lb
if m.y.ub is None:
yu = np.inf
else:
yu = m.y.ub
for _x in x:
_y = np.log(abs(z)) / np.log(abs(_x))
self.assertTrue(np.all(yl <= _y))
self.assertTrue(np.all(yu >= _y))
def test_pow4(self):
y_bounds = [(0.5, 2.8), (0, 2.8), (1, 2.8), (0.5, 1), (0, 0.5)]
exp_vals = [-3, -2.5, -2, -1.5, -1, -0.5, 0.5, 1, 1.5, 2, 2.5, 3]
for yl, yu in y_bounds:
for _exp_val in exp_vals:
m = pyo.Block(concrete=True)
m.x = pyo.Var()
m.y = pyo.Var(bounds=(yl, yu))
m.c = pyo.Constraint(expr=m.x**_exp_val == m.y)
fbbt(m)
y = np.linspace(pyo.value(m.y.lb) + 1e-6,
pyo.value(m.y.ub),
100,
endpoint=True)
if m.x.lb is None:
xl = -np.inf
else:
xl = m.x.lb
if m.x.ub is None:
xu = np.inf
else:
xu = m.x.ub
_x = np.exp(np.log(y) / _exp_val)
self.assertTrue(np.all(xl <= _x))
self.assertTrue(np.all(xu >= _x))
def test_exp(self):
xl = -2.5
xu = 2.8
zl, zu = interval.exp(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.exp(x)
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_log(self):
x_bounds = [(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)), (0, 0)]
for xl, xu in x_bounds:
zl, zu = interval.log(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.log(x)
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_exp(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
xl = -2.5
xu = 2.8
zl, zu = self.exp(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.exp(x)
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_log(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
x_bounds = [(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)), (0, 0)]
for xl, xu in x_bounds:
zl, zu = self.log(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.log(x)
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_tan(self):
lbs = np.linspace(-2 * math.pi, 2 * math.pi, 10)
ubs = np.linspace(-2 * math.pi, 2 * math.pi, 10)
for xl in lbs:
for xu in ubs:
if xu >= xl:
zl, zu = interval.tan(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.tan(x)
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_mul(self):
xl = -2.5
xu = 2.8
yl = -3.2
yu = 2.7
zl, zu = interval.mul(xl, xu, yl, yu)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x * y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_tan(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
lbs = np.linspace(-2 * math.pi, 2 * math.pi, 10)
ubs = np.linspace(-2 * math.pi, 2 * math.pi, 10)
for xl in lbs:
for xu in ubs:
if xu >= xl:
zl, zu = self.tan(xl, xu)
x = np.linspace(xl, xu, 100)
_z = np.tan(x)
self.assertTrue(np.all(zl <= _z + 1e-14))
self.assertTrue(np.all(zu >= _z - 1e-14))
def test_mul(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
xl = -2.5
xu = 2.8
yl = -3.2
yu = 2.7
zl, zu = self.mul(xl, xu, yl, yu)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x * y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_div(self):
x_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5))]
y_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)),
(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), 0),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0))]
for xl, xu in x_bounds:
for yl, yu in y_bounds:
zl, zu = interval.div(xl, xu, yl, yu, feasibility_tol=1e-8)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x / y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_div(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
x_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5))]
y_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)),
(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), 0),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0))]
for xl, xu in x_bounds:
for yl, yu in y_bounds:
zl, zu = self.div(xl, xu, yl, yu, 1e-8)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x / y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def __init__(self, center, shape_matrix, scale=1):
"""
EllipsoidalSet constructor
Args:
center: Vector (``list``) of uncertain parameter values around which deviations are restrained.
shape_matrix: Positive semi-definite matrix, effectively a covariance matrix for
constraint and bounds determination.
scale: Right-hand side value for the ellipsoid.
"""
# === Valid data in lists/matrixes
if not all(isinstance(elem, (int, float)) for row in shape_matrix for elem in row):
raise AttributeError("Matrix shape_matrix must be real-valued and numeric.")
if not all(isinstance(elem, (int, float)) for elem in center):
raise AttributeError("Vector center must be real-valued and numeric.")
if not isinstance(scale, (int, float)):
raise AttributeError("Ellipse scale must be a real-valued numeric.")
# === Valid matrix dimensions
num_cols = len(shape_matrix[0])
if not all(len(row) == num_cols for row in shape_matrix):
raise AttributeError("Shape matrix must have valid matrix dimensions.")
# === Ensure shape_matrix is a square matrix
array_shape_mat = np.asarray(shape_matrix)
if array_shape_mat.shape[0] != array_shape_mat.shape[1]:
raise AttributeError("Shape matrix must be square.")
# === Ensure dimensions of shape_matrix are same as dimensions of uncertain_params
if array_shape_mat.shape[1] != len(center):
raise AttributeError("Shape matrix must be "
"same dimensions as vector of uncertain parameters.")
# === Symmetric shape_matrix
if not np.all(np.abs(array_shape_mat-array_shape_mat.T) < 1e-8):
raise AttributeError("Shape matrix must be symmetric.")
# === Ensure scale is non-negative
if scale < 0:
raise AttributeError("Scale of ellipse (rhs) must be non-negative.")
# === Check if shape matrix is invertible
try:
np.linalg.inv(shape_matrix)
except np.linalg.LinAlgError as err:
raise("Error with shape matrix supplied to EllipsoidalSet object being singular. %s" % err)
# === Check is shape matrix is positive semidefinite
if not all(np.linalg.eigvals(shape_matrix) >= 0):
raise("Non positive-semidefinite shape matrix.")
# === Ensure matrix is not degenerate, for determining inferred bounds
try:
for i in range(len(shape_matrix)):
np.power(shape_matrix[i][i], 0.5)
except:
raise AttributeError("Shape matrix must be non-degenerate.")
self.center = center
self.shape_matrix = shape_matrix
self.scale = scale
self.type = "ellipsoidal"
def test_log(self):
c_bounds = [(-2.5, 2.8), (-2.5, -0.5), (0.5, 2.8), (-2.5, 0), (0, 2.8),
(-2.5, -1), (1, 2.8), (-1, -0.5), (0.5, 1)]
for cl, cu in c_bounds:
m = pyo.Block(concrete=True)
m.x = pyo.Var()
m.c = pyo.Constraint(
expr=pyo.inequality(body=pyo.log(m.x), lower=cl, upper=cu))
fbbt(m)
z = np.linspace(pyo.value(m.c.lower), pyo.value(m.c.upper), 100)
if m.x.lb is None:
xl = -np.inf
else:
xl = pyo.value(m.x.lb)
if m.x.ub is None:
xu = np.inf
else:
xu = pyo.value(m.x.ub)
x = np.exp(z)
self.assertTrue(np.all(xl <= x))
self.assertTrue(np.all(xu >= x))
def test_pow(self):
if not numpy_available:
raise unittest.SkipTest('Numpy is not available.')
x_bounds = [(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)), (0, 0)]
y_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(0, np.random.uniform(2, 5)),
(np.random.uniform(0, 2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), 0),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0))]
for xl, xu in x_bounds:
for yl, yu in y_bounds:
zl, zu = self.power(xl, xu, yl, yu, 1e-8)
if xl == 0 and xu == 0 and yu < 0:
self.assertEqual(zl, -interval.inf)
self.assertEqual(zu, interval.inf)
x = np.linspace(xl, xu, 100)
y = np.linspace(yl, yu, 100)
for _x in x:
_z = _x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
x_bounds = [(np.random.uniform(-5, -2), np.random.uniform(2, 5)),
(np.random.uniform(-5, -2), np.random.uniform(-2, 0)),
(np.random.uniform(-5, -2), 0)]
y_bounds = list(range(-4, 4))
for xl, xu in x_bounds:
for yl in y_bounds:
yu = yl
zl, zu = self.power(xl, xu, yl, yu, 1e-8)
x = np.linspace(xl, xu, 100, endpoint=False)
y = yl
_z = x**y
self.assertTrue(np.all(zl <= _z))
self.assertTrue(np.all(zu >= _z))
def test_exp(self):
c_bounds = [(-2.5, 2.8), (0.5, 2.8), (0, 2.8), (1, 2.8), (0.5, 1)]
for cl, cu in c_bounds:
m = pe.Block(concrete=True)
m.x = pe.Var()
m.c = pe.Constraint(
expr=pe.inequality(body=pe.exp(m.x), lower=cl, upper=cu))
fbbt(m)
if pe.value(m.c.lower) <= 0:
_cl = 1e-6
else:
_cl = pe.value(m.c.lower)
z = np.linspace(_cl, pe.value(m.c.upper), 100)
if m.x.lb is None:
xl = -np.inf
else:
xl = pe.value(m.x.lb)
if m.x.ub is None:
xu = np.inf
else:
xu = pe.value(m.x.ub)
x = np.log(z)
self.assertTrue(np.all(xl <= x))
self.assertTrue(np.all(xu >= x))
