def test_primitive_cell_for_triclinic_lattice(self):
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(-1, -2, -3, 0.5, 0.6, 0.7)
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 0, np.pi, np.pi)
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 0.1, 0.2, 0.8)
with self.assertRaises(ValueError):
# angles too big
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 2.1, 2.1, 2.1)
cosa = np.cos(self.alpha)
cosb = np.cos(self.beta)
sinb = np.sin(self.beta)
cosg = np.cos(self.gamma)
sing = np.sin(self.gamma)
p1 = (self.a, 0, 0)
p2 = (self.b * cosg, self.b * sing, 0)
p3 = (self.c * cosb, self.c * (cosa - cosb * cosg) / sing,
self.c * np.sqrt(sinb**2 - ((cosa - cosb * cosg) / sing)**2))
pc = PrimitiveCell.for_triclinic_lattice(self.a, self.b, self.c,
self.alpha, self.beta,
self.gamma)
self.assertIsInstance(pc, PrimitiveCell)
self.assertEqual(pc.bravais_lattice, BravaisLattice.TRICLINIC)
assert_array_equal(pc.p1, p1)
assert_array_equal(pc.p2, p2)
assert_array_equal(pc.p3, p3)
def test_primitive_cell_for_triclinic_lattice(self):
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(-1, -2, -3, 0.5, 0.6, 0.7)
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 0, np.pi, np.pi)
with self.assertRaises(ValueError):
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 0.1, 0.2, 0.8)
with self.assertRaises(ValueError):
# angles too big
PrimitiveCell.for_triclinic_lattice(1, 2, 3, 2.1, 2.1, 2.1)
cosa = np.cos(self.alpha)
cosb = np.cos(self.beta)
sinb = np.sin(self.beta)
cosg = np.cos(self.gamma)
sing = np.sin(self.gamma)
p1 = (self.a, 0, 0)
p2 = (self.b*cosg, self.b*sing, 0)
p3 = (self.c*cosb, self.c*(cosa-cosb*cosg) / sing,
self.c*np.sqrt(sinb**2 - ((cosa-cosb*cosg) / sing)**2))
pc = PrimitiveCell.for_triclinic_lattice(
self.a, self.b, self.c, self.alpha, self.beta, self.gamma)
self.assertIsInstance(pc, PrimitiveCell)
self.assertEqual(pc.bravais_lattice,
BravaisLattice.TRICLINIC)
assert_array_equal(pc.p1, p1)
assert_array_equal(pc.p2, p2)
assert_array_equal(pc.p3, p3)
def make_triclinic_lattice(name, hs, angles, size, origin=(0, 0, 0)):
"""Create and return a 3D triclinic lattice.
Parameters
----------
name : str
hs : float[3]
lattice spacings in each axis direction
angles : float[3]
angles between the (conventional) unit cell edges (in radians)
size : int[3]
Number of lattice nodes in each axis direction.
origin : float[3], default value = (0, 0, 0)
lattice origin
Returns
-------
lattice : Lattice
A reference to a Lattice object.
"""
pc = PrimitiveCell.for_triclinic_lattice(
hs[0], hs[1], hs[2], angles[0], angles[1], angles[2])
return Lattice(name, pc, size, origin)
def test_cell_volume(self):
pc = PrimitiveCell.for_triclinic_lattice(1, 1, 1, np.pi / 2, np.pi / 2,
np.pi / 2)
self.assertAlmostEqual(pc.volume, 1)
def test_cell_volume(self):
pc = PrimitiveCell.for_triclinic_lattice(1, 1, 1, np.pi/2,
np.pi/2, np.pi/2)
self.assertAlmostEqual(pc.volume, 1)
