def test_gvectors_fcc():
from numpy import array, allclose, sqrt
from numpy.linalg import norm
from itertools import chain
from pylada.crystal import _space_group
cell = array([[0, 0.5, 0.5], [0.5, 0, 0.5], [0.5, 0.5, 0]])
result = _space_group.__gvectors(cell, 1e-12)
assert len(result) == 3
assert len(result[0]) > 0
assert len(result[0]) == len(result[1])
assert len(result[0]) == len(result[2])
# check directions are equivalent and each vector is unique
for vectors in result:
for vector in vectors:
assert sum([allclose(u, vector) for u in result[0]]) == 1
for vector in result[0]:
assert abs(norm(vector) - 0.5 * sqrt(2.)) < 1e-8
def test_gvectors_non_fcc():
from numpy import array, allclose, sqrt
from numpy.linalg import norm
from itertools import chain
from pylada.crystal import _space_group
cell = array([[0.6, 0.5, 0.5], [0.6, -0.5, 0.5], [0.6, 0.5, -0.5]])
result = _space_group.__gvectors(cell, 1e-12)
assert len(result) == 3
assert len(result[0]) > 0
assert len(result[1]) == len(result[2])
# check directions 1 and 2 are equivalent
for vector in result[1]:
assert sum([allclose(u, vector) for u in result[2]]) == 1
# check unicity
for vector in result[0]:
assert sum([allclose(u, vector) for u in result[0]]) == 1
for vector in result[1]:
assert sum([allclose(u, vector) for u in result[1]]) == 1
for vector in result[0]:
assert abs(norm(vector) - 0.6 * sqrt(3.)) < 1e-8
for vector in result[1]:
assert abs(norm(vector) - 0.5 * sqrt(3.)) < 1e-8