def test_get_dQ(self):
self.assertEqual(get_dQ(self.gnd_test, self.gnd_test), 0.)
self.assertEqual(get_dQ(self.exd_test, self.exd_test), 0.)
self.assertEqual(get_dQ(self.gnd_real, self.gnd_real), 0.)
self.assertEqual(get_dQ(self.exd_real, self.exd_real), 0.)
self.assertAlmostEqual(get_dQ(self.gnd_test, self.exd_test), 0.86945,
places=4)
self.assertAlmostEqual(get_dQ(self.gnd_real, self.exd_real), 1.68587,
places=4)
def test_get_Q_from_struct(self):
q = get_Q_from_struct(self.gnd_test, self.exd_test, self.sct_test)
self.assertAlmostEqual(q, 0.5 * 0.86945, places=4)
q = get_Q_from_struct(self.gnd_real, self.exd_real,
str(TEST_FILES / 'POSCAR.C0.gz'))
self.assertAlmostEqual(q, 0., places=4)
gs, es = get_cc_structures(self.gnd_real, self.exd_real,
np.linspace(-0.5, 0.5, 100),
remove_zero=False)
Q = 1.68587 * np.linspace(-0.5, 0.5, 100)
for s, q in zip(gs, Q):
tq = get_Q_from_struct(self.gnd_real, self.exd_real, s)
self.assertAlmostEqual(tq, q, places=4)
for s, q in zip(es, Q + 1.68587):
tq = get_Q_from_struct(self.gnd_real, self.exd_real, s)
self.assertAlmostEqual(tq, q, places=4)
# test when one of the coordinates stays the same
sg = pmg.Structure(np.eye(3), ['H'], [[0.0, 0.0, 0.0]])
sq = pmg.Structure(np.eye(3), ['H'], [[0.1, 0.0, 0.1]])
se = pmg.Structure(np.eye(3), ['H'], [[0.2, 0.0, 0.2]])
dQ = get_dQ(sg, se)
self.assertAlmostEqual(get_Q_from_struct(sg, se, sq)/dQ, 0.5)