def test_distance_fractional(self):
""" Test the fractional distance between atoms """
atm1 = Atom("He", [0, 0, 0])
atm2 = Atom("He", [1, 0, 0])
self.assertEqual(distance_fractional(atm1, atm2), 1)
self.assertEqual(distance_fractional(atm1, atm2),
distance_fractional(atm2, atm1))
def test_distance_cartesian(self):
""" Test the cartesian distance between atom """
lattice = Lattice(4 * np.eye(3)) # Cubic lattice side length 4 angs
atm1 = Atom("He", [0, 0, 0], lattice=lattice)
atm2 = Atom("He", [1, 0, 0], lattice=lattice)
self.assertEqual(distance_cartesian(atm1, atm2), 4.0)
def test_atomic_distance_cartesian():
"""Test the cartesian distance between atom"""
lattice = Lattice(4 * np.eye(3)) # Cubic lattice side length 4 angs
atm1 = Atom("He", [0, 0, 0], lattice=lattice)
atm2 = Atom("He", [1, 0, 0], lattice=lattice)
assert distance_cartesian(atm1, atm2) == 4.0
def test_substructure_preservation(self):
""" Test that initializing a crystal with substructures preserves the substructures """
atoms = [Atom("Ag", [0, 0, 0]), Atom("Ag", [1, 1, 1])]
substructures = [AtomicStructure(atoms=[Atom("U", [0, 0, 0])])]
c = Crystal(unitcell=atoms + substructures, lattice_vectors=np.eye(3))
self.assertEqual(len(c), 3)
self.assertIn(substructures[0], c.substructures)
def test_substructure_preservation():
"""Test that initializing a crystal with substructures preserves the substructures"""
atoms = [Atom("Ag", [0, 0, 0]), Atom("Ag", [1, 1, 1])]
substructures = [AtomicStructure(atoms=[Atom("U", [0, 0, 0])])]
c = Crystal(unitcell=atoms + substructures, lattice_vectors=np.eye(3))
assert len(c) == 3
assert substructures[0] in c.substructures
def test_transform_subclass(structure):
"""Test that the object returned by the transform() method is the
same class as the method caller."""
class NewAtomicStructure(AtomicStructure):
pass
structure = NewAtomicStructure(atoms=[Atom("Ag", [0, 0, 0]), Atom("Ag", [1, 1, 1])])
transformed = structure.transform(np.eye(3))
assert type(transformed) is type(structure)
def test_chemical_formula_hill_notation(structure):
""" Test that the Hill notation, where elements are alphabetically ordered except C and H, which are first. """
structure = AtomicStructure(
atoms=[
Atom("Ag", [0, 1, 0]),
Atom("C", [0, 0, 0]),
Atom("H", [0, 1, 0]),
Atom("U", [1, 1, 1]),
]
)
assert structure.chemical_formula == "C H Ag U"
def test_atomic_distance_different_lattice():
"""Test that fractional and cartesian distances
between atoms in different lattices raises an error."""
lattice1 = Lattice(np.eye(3))
lattice2 = Lattice(2 * np.eye(3))
atm1 = Atom("He", [0, 0, 0], lattice=lattice1)
atm2 = Atom("He", [1, 0, 0], lattice=lattice2)
with pytest.raises(RuntimeError):
distance_fractional(atm1, atm2)
with pytest.raises(RuntimeError):
distance_cartesian(atm1, atm2)
def test_addition(structure):
""" Test the addition of two different AtomicStructures works as expected. """
new_struct = AtomicStructure(
atoms=[Atom("U", [0, 1, 0])],
substructures=[
AtomicStructure(atoms=[Atom("Ag", [0.5, 0, 0]), Atom("Ag", [1, 0.3, 1])])
],
)
addition = structure + new_struct
assert len(new_struct) + len(structure) == len(addition)
assert len(new_struct.atoms) + len(structure.atoms) == len(addition.atoms)
assert len(new_struct.substructures) + len(structure.substructures) == len(
addition.substructures
)
def test_distance_different_lattice(self):
""" Test that fractional and cartesian distances
between atoms in different lattices raises an error. """
lattice1 = Lattice(np.eye(3))
lattice2 = Lattice(2 * np.eye(3))
atm1 = Atom("He", [0, 0, 0], lattice=lattice1)
atm2 = Atom("He", [1, 0, 0], lattice=lattice2)
with self.subTest("Fractional distance"):
with self.assertRaises(RuntimeError):
distance_fractional(atm1, atm2)
with self.subTest("Cartesian distance"):
with self.assertRaises(RuntimeError):
distance_cartesian(atm1, atm2)
def test_trivial(self):
""" Test that the symmetry_reduction function returns the unit cell when
there is only one possibility. """
ucell = set([Atom("H", coords=[0, 0, 0])])
symops = [np.eye(4)]
asym_cell = symmetry_reduction(ucell, symops)
self.assertEqual(ucell, asym_cell)
def aspherical_affe(atom, s):
"""
Aspherical atomic form factors for electron scattering.
Only atoms lighter than Xe (and including) are supported (Z <= 54).
Parameters
----------
atom : crystals.Atom, int, or str
Atomic number, atomic symbol, or Atom instance.
Atomic symbols are expected to be properly capitalized, e.g. ``As`` or ``W``.
Note that if `atom` is provided as an int or str, the ground state electronic structure
is used. If an `crystals.Atom` object is provided, then its electronic structure will
be used to construct the electron form factor.
s : array_like
Scattering vector norm
Returns
-------
eff : `~numpy.ndarray`, dtype float
Atomic form factor for electron scattering.
Raises
------
ValueError : scattering information is not available, for example if the atomic number is larger than 54
References
----------
.. [#] Jin-Cheng Zheng, Lijun Wu and Yimei Zhu. "Aspherical electron scattering factors and their
parameterizations for elements from H to Xe" (2009). J. Appl. Cryst. vol 42, pp. 1043 - 1053.
"""
if isinstance(atom, (int, str)):
atom = Atom(atom)
element = atom.element
return _affe_parametrization(s, aspherical_ff[element]["total"])
def test_input_types(self):
""" Test that is_element() works as expected for all
supported input types """
atm = Atom("V", [0, 0, 0])
self.assertTrue(is_element(atm.element)(atm))
self.assertTrue(is_element(atm.atomic_number)(atm))
self.assertTrue(is_element(atm)(atm))
def test_symmetry_reduction_simple_translation():
"""Test that symmetry_reduction works on a unitcell where two atoms are
linked by a translation"""
symops = [np.eye(4), translation_matrix([0, 0, 1 / 3])]
asym_cell = set([Atom("H", coords=[0, 0, 0])])
unitcell = set(symmetry_expansion(asym_cell, symmetry_operators=symops))
asym_cell2 = symmetry_reduction(unitcell, symops)
assert asym_cell == asym_cell2
def __init__(self, unitCell, latticeVectors):
self._unitCell = [Atom(atom[0], coords=atom[1]) for atom in unitCell]
Crystal.__init__(self, self._unitCell, latticeVectors)
self.atomsPerUnitCell = len(unitCell)
self.atomicWeights = [atom.mass for atom in self._unitCell]
self.atomLabels = [
f'{inx}_{atom.element}'
for atom, inx in zip(self._unitCell, range(self.atomsPerUnitCell))
]
def test_int(self):
""" Test that affe(int, ...) also works """
atomic_number = randint(1, 103)
nG = np.random.random(size=(16, 32))
from_int = affe(atomic_number, nG)
from_atom = affe(Atom(atomic_number, [0, 0, 0]), nG)
self.assertTrue(np.allclose(from_int, from_atom))
def test_addition(self):
""" Test the addition of two different AtomicStructures works as expected. """
new_struct = AtomicStructure(
atoms=[Atom("U", [0, 1, 0])],
substructures=[
AtomicStructure(
atoms=[Atom("Ag", [0.5, 0, 0]), Atom("Ag", [1, 0.3, 1])]
)
],
)
addition = self.structure + new_struct
self.assertEqual(len(new_struct) + len(self.structure), len(addition))
self.assertEqual(
len(new_struct.atoms) + len(self.structure.atoms), len(addition.atoms)
)
self.assertEqual(
len(new_struct.substructures) + len(self.structure.substructures),
len(addition.substructures),
)
def _generate_unitcell_atoms(crystal: Crystal):
for atm in crystal:
for factors in product(range(-2, 2), range(-2, 2), range(-2, 2)):
coords = atm.coords_fractional + np.asarray(factors)
if np.all(coords <= 1.1) and np.all(coords >= -0.1):
yield Atom(
element=atm.element,
coords=coords,
lattice=Lattice(crystal.lattice_vectors),
displacement=atm.displacement,
magmom=atm.magmom,
occupancy=atm.occupancy,
)
def structure():
substructure = AtomicStructure(atoms=[Atom("U", [0, 0, 0])])
return AtomicStructure(
atoms=[Atom("Ag", [0, 0, 0]), Atom("Ag", [1, 1, 1])],
substructures=[substructure],
)
def test_out_shape(self):
nG = np.random.random(size=(16, 32))
eff = affe(Atom("He", coords=[0, 0, 0]), nG)
self.assertSequenceEqual(eff.shape, nG.shape)
def test_side_effects(self):
nG = np.random.random(size=(16, 32))
nG.setflags(write=False) # if nG is written to, Exception is raised
affe(Atom("He", coords=[0, 0, 0]), nG)
def test_init(self):
""" Test that Atom can be instantiated with an element str or atomic number """
by_element = Atom("C", coords=(0, 0, 0))
by_number = Atom(6, coords=(0, 0, 0))
self.assertEqual(by_element, by_number)
def setUp(self):
self.atom = Atom(randint(1, 103), coords=np.random.random((3, )))
def test_out_shape():
nG = np.random.random(size=(16, 32))
eff = affe(Atom("He", coords=[0, 0, 0]), nG)
assert eff.shape == nG.shape
assert Element("H") == expected
assert Element("Hydrogen") == expected
assert Element("hydrogen") == expected # not case sensitive
assert Element(1) == expected
assert Element(expected) == expected
def test_atom_init():
"""Test that Atom can be instantiated with an element str or atomic number"""
by_element = Atom("C", coords=(0, 0, 0))
by_number = Atom(6, coords=(0, 0, 0))
assert by_element == by_number
@pytest.mark.parametrize("atom",
map(lambda s: Atom(s, [0, 0, 0]),
islice(chemical_symbols, 50)))
def test_atom_equality(atom):
"""Test __eq__ for atoms"""
other = deepcopy(atom)
assert atom == atom
assert atom == other
other.coords_fractional = atom.coords_fractional + 1
assert atom != other
@pytest.mark.parametrize("atom",
map(lambda s: Atom(s, [0, 0, 0]),
islice(chemical_symbols, 50)))
def test_atom_trivial_transform(atom):
def test_atomic_distance_fractional():
"""Test the fractional distance between atoms"""
atm1 = Atom("He", [0, 0, 0])
atm2 = Atom("He", [1, 0, 0])
assert distance_fractional(atm1, atm2) == 1
assert distance_fractional(atm1, atm2) == distance_fractional(atm2, atm1)
def test_atom_init():
"""Test that Atom can be instantiated with an element str or atomic number"""
by_element = Atom("C", coords=(0, 0, 0))
by_number = Atom(6, coords=(0, 0, 0))
assert by_element == by_number
from crystals import Crystal,Atom,symmetry_expansion,write_xyz
# import rotating_crystal as rcc; imp.reload(rcc)
cif='225.cif' #201(SC), 212,225,229
lattice_vectors = np.diag([2,2,2])
cCIF = Crystal.from_cif('../dat/Carbone_SC/'+cif)
# cCIF = Crystal.from_database('Fe')
syms = cCIF.symmetry_operations()
atoms = [Atom(z, c) for z,c in zip(['C','C','C'], [[0.5,0.5,0],[0,0.5,0.5],[0.5,0.,0.5]]) ]
# atoms = [Atom('C', [0.5,0.5,1])]
# atoms = [Atom('C', [1.,1.,1.])]
syms4 = [ np.hstack([np.vstack([s[0],[0,0,0]]), np.vstack([s[1][:,None],1]) ]) for s in syms]
unitcell = symmetry_expansion(atoms,syms4)
C = Crystal(unitcell, lattice_vectors)
print('international_number:', cCIF.symmetry()['international_number'])
print('international_number:', C.symmetry()['international_number'])
print(C)
# write_xyz(C,'test.xyz')
def setUp(self):
self.substructure = AtomicStructure(atoms=[Atom("U", [0, 0, 0])])
self.structure = AtomicStructure(
atoms=[Atom("Ag", [0, 0, 0]), Atom("Ag", [1, 1, 1])],
substructures=[self.substructure],
)