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import unittest
import numpy as np
from spglib import get_magnetic_symmetry, get_symmetry
class TestGetOperationsWithSiteTensors(unittest.TestCase):
def setUp(self):
lattice = [[0, 2, 2], [2, 0, 2], [2, 2, 0]]
positions = [[0, 0, 0]]
numbers = [1]
magmoms = [[0, 0, 1]]
self._cell_Ni = (lattice, positions, numbers, magmoms)
# CrCl2, adapted from Example 1 in Tutorial-MAXMAGN:
# http://webbdcrista1.ehu.es/cryst/tutorials/Tutorial-MAXMAGN.pdf
lattice = [
[6.8257, 0, 0],
[0, 6.2139, 0],
[0, 0, 3.4947],
]
positions = [
# Cr (2a), site symmetry: < -x,-y,-z; -x,-y,z >
[0, 0, 0],
[0.5, 0.5, 0.5],
# Cl (4g)
[0.3586, 0.2893, 0],
[-0.3586, -0.2893, 0],
[-0.3586 + 0.5, 0.2893 + 0.5, 0.5],
[0.3586 + 0.5, -0.2893 + 0.5, 0.5],
]
numbers = [1, 1, 2, 2, 2, 2]
self._cell_CrCl2 = (lattice, positions, numbers)
def tearDown(self):
pass
def test_get_symmetry_non_collinear(self):
sym = get_magnetic_symmetry(self._cell_Ni, with_time_reversal=False)
self.assertEqual(8, len(sym["rotations"]))
np.testing.assert_equal(sym["equivalent_atoms"], [0])
# type-III magnetic space group
sym2 = get_magnetic_symmetry(self._cell_Ni)
self.assertEqual(16, len(sym2["rotations"]))
self.assertEqual(16, len(sym2["translations"]))
self.assertEqual(16, len(sym2["time_reversals"]))
def test_get_symmetry_vectors(self):
# Space group without magnetic moments
# Pnnm (58), "-P 2 2n" (hall_number=275)
# Generators: -x,-y,-z; -x,-y,z; -x+1/2,y+1/2,-z+1/2
sym = get_symmetry(self._cell_CrCl2)
self.assertEqual(8, len(sym["rotations"]))
# Type-I magnetic space group (MSG)
magmoms1 = [
[0, 0, 1],
[0, 0, -1],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
]
sym1 = get_magnetic_symmetry(self._cell_CrCl2 + (magmoms1,))
self.assertTrue(np.allclose(sym1["time_reversals"], False))
self.assertTrue(np.allclose(sym1["rotations"], sym["rotations"]))
self.assertTrue(np.allclose(sym1["translations"], sym["translations"]))
# Type-II MSG
# 58.394, -P 2 2n 1'
magmoms2 = [
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
]
sym2 = get_magnetic_symmetry(self._cell_CrCl2 + (magmoms2,))
self.assertEqual(len(sym2["rotations"]), 16)
self.assertEqual(np.sum(sym2["time_reversals"]), 8)
sym2_gray = get_magnetic_symmetry(
self._cell_CrCl2 + (magmoms2,),
with_time_reversal=False,
)
self.assertTrue(np.allclose(sym2_gray["rotations"], sym["rotations"]))
self.assertTrue(np.allclose(sym2_gray["translations"], sym["translations"]))
# Type-III MSG
# 58.397: -P 2 2n'
# Generators: -x,-y,-z; -x,-y,z; -x+1/2,y+1/2,-z+1/2'
magmoms3 = [
[0, 0, 1],
[0, 0, 1],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
]
sym3 = get_magnetic_symmetry(self._cell_CrCl2 + (magmoms3,))
self.assertTrue(np.allclose(sym3["rotations"], sym["rotations"]))
self.assertTrue(np.allclose(sym3["translations"], sym["translations"]))
self.assertTrue(np.sum(sym3["time_reversals"]), 4)
# Type-IV MSG
# https://github.com/spglib/spglib/issues/150
# -P 2 2 -> -P 2 2 1c' (47.254)
lat = [[1, 0, 0], [0, 2, 0], [0, 0, 3]]
pos = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.5]]
num = [0, 0]
magmom = [[0.0, 0.0, 1.0], [0.0, 0.0, -1.0]]
sym_gray = get_symmetry((lat, pos, num))
sym4 = get_magnetic_symmetry((lat, pos, num, magmom))
self.assertTrue(np.allclose(sym_gray["rotations"], sym4["rotations"]))
self.assertTrue(np.allclose(sym_gray["translations"], sym4["translations"]))
self.assertTrue(sym4["time_reversals"].shape[0], 16)
self.assertTrue(np.sum(sym4["time_reversals"]), 8)
self.assertTrue(np.allclose(sym4["primitive_lattice"], lat))
def test_with_distorted_magmom(self):
magmoms = [
[0, 0, 1.001],
[0, 0, 0.999],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
[0, 0, 0],
]
sym = get_magnetic_symmetry(self._cell_CrCl2 + (magmoms,), mag_symprec=1e-2)
expect = [0, 0, 2, 2, 2, 2]
assert np.allclose(sym["equivalent_atoms"], expect)
if __name__ == "__main__":
suite = unittest.TestLoader().loadTestsFromTestCase(
TestGetOperationsWithSiteTensors,
)
unittest.TextTestRunner(verbosity=2).run(suite)
# unittest.main()
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