def _expandAsymmetricUnit(self):
"""Perform symmetry expansion of self.stru using self.spacegroup.
This method updates data in stru and eau.
No return value.
"""
from diffpy.structure.symmetryutilities import ExpandAsymmetricUnit
# get reverse-ordered unique indices
corepos = [a.xyz for a in self.stru]
coreUijs = [a.U for a in self.stru]
self.eau = ExpandAsymmetricUnit(self.spacegroup, corepos, coreUijs,
eps=self.eps)
# build a nested list of new atoms:
newatoms = []
for i, ca in enumerate(self.stru):
eca = [] # expanded core atom
for j in range(self.eau.multiplicity[i]):
a = Atom(ca)
a.xyz = self.eau.expandedpos[i][j]
if j > 0:
a.label += '_' + str(j + 1)
if a.anisotropy:
a.U = self.eau.expandedUijs[i][j]
eca.append(a)
newatoms.append(eca)
# insert new atoms where they belong
self.stru[:] = sum(newatoms, [])
return
def supercell(S, mno):
"""Perform supercell expansion for a structure.
New lattice parameters are multiplied and fractional coordinates
divided by corresponding multiplier. New atoms are grouped with
their source in the original cell.
S -- an instance of Structure from diffpy.structure.
mno -- sequence of 3 integers for cell multipliers along
the a, b and c axes.
Return a new expanded structure instance.
Raise TypeError when S is not Structure instance.
Raise ValueError for invalid mno argument.
"""
# check arguments
if len(mno) != 3:
emsg = "Argument mno must contain 3 numbers."
raise ValueError(emsg)
elif min(mno) < 1:
emsg = "Multipliers must be greater or equal 1"
raise ValueError(emsg)
if not isinstance(S, Structure):
emsg = "The first argument must be a Structure instance."
raise TypeError(emsg)
# convert mno to a tuple of integers so it can be used as range limit.
mno = (int(mno[0]), int(mno[1]), int(mno[2]))
# create return instance
newS = Structure(S)
if mno == (1, 1, 1):
return newS
# back to business
ijklist = [(i,j,k)
for i in range(mno[0])
for j in range(mno[1])
for k in range(mno[2])]
# numpy.floor returns float array
mnofloats = numpy.array(mno, dtype=float)
# build a list of new atoms
newAtoms = []
for a in S:
for ijk in ijklist:
adup = Atom(a)
adup.xyz = (a.xyz + ijk)/mnofloats
newAtoms.append(adup)
# newS can own references in newAtoms, no need to make copies
newS.__setitem__(slice(None), newAtoms, copy=False)
# take care of lattice parameters
newS.lattice.setLatPar(
a=mno[0]*S.lattice.a,
b=mno[1]*S.lattice.b,
c=mno[2]*S.lattice.c )
return newS
def _dummyAtomWithBiso(crystal, biso):
from numpy import degrees
from diffpy.structure import Lattice, Atom
lattice = Lattice(crystal.a, crystal.b, crystal.c,
degrees(crystal.alpha),
degrees(crystal.beta),
degrees(crystal.gamma))
a = Atom('X', anisotropy=False, lattice=lattice)
a.Bisoequiv = biso
return a
def supercell(S, mno):
"""Perform supercell expansion for a structure.
New lattice parameters are multiplied and fractional coordinates
divided by corresponding multiplier. New atoms are grouped with
their source in the original cell.
S -- an instance of Structure from diffpy.structure.
mno -- sequence of 3 integers for cell multipliers along
the a, b and c axes.
Return a new expanded structure instance.
Raise TypeError when S is not Structure instance.
Raise ValueError for invalid mno argument.
"""
# check arguments
if len(mno) != 3:
emsg = "Argument mno must contain 3 numbers."
raise ValueError(emsg)
elif min(mno) < 1:
emsg = "Multipliers must be greater or equal 1"
raise ValueError(emsg)
if not isinstance(S, Structure):
emsg = "The first argument must be a Structure instance."
raise TypeError(emsg)
# convert mno to a tuple of integers so it can be used as range limit.
mno = (int(mno[0]), int(mno[1]), int(mno[2]))
# create return instance
newS = Structure(S)
if mno == (1, 1, 1):
return newS
# back to business
ijklist = [(i, j, k) for i in range(mno[0]) for j in range(mno[1])
for k in range(mno[2])]
# numpy.floor returns float array
mnofloats = numpy.array(mno, dtype=float)
# build a list of new atoms
newAtoms = []
for a in S:
for ijk in ijklist:
adup = Atom(a)
adup.xyz = (a.xyz + ijk) / mnofloats
newAtoms.append(adup)
# newS can own references in newAtoms, no need to make copies
newS.__setitem__(slice(None), newAtoms, copy=False)
# take care of lattice parameters
newS.lattice.setLatPar(a=mno[0] * S.lattice.a,
b=mno[1] * S.lattice.b,
c=mno[2] * S.lattice.c)
return newS
def test_writeStr_xyz(self):
"""check string representation of normal xyz file"""
stru = self.stru
stru.title = "test of writeStr"
stru.lattice = Lattice(1.0, 2.0, 3.0, 90.0, 90.0, 90.0)
stru[:] = [Atom('H', [1., 1., 1.]), Atom('Cl', [3., 2., 1.])]
s1 = stru.writeStr(self.format)
s1 = re.sub('[ \t]+', ' ', s1)
s0 = "2\n%s\nH 1 2 3\nCl 3 4 3\n" % stru.title
self.assertEqual(s1, s0)
return
def ferrite_phase():
return Phase(
name="ferrite",
space_group=229,
structure=Structure(
lattice=Lattice(2.8665, 2.8665, 2.8665, 90, 90, 90),
atoms=[
Atom(xyz=[0, 0, 0], atype="Fe", Uisoequiv=0.006332),
Atom(xyz=[0.5, 0.5, 0.5], atype="Fe", Uisoequiv=0.006332),
],
),
)
def setUp(self):
self.stru = Structure(
[Atom('C', [0, 0, 0]), Atom('C', [1, 1, 1])],
lattice=Lattice(1, 1, 1, 90, 90, 120))
if not self._loaded_structures:
self._loaded_structures.update([
('cdse', Structure(filename=cdsefile)),
('tei', Structure(filename=teifile)),
('pbte', Structure(filename=pbtefile)),
])
self.__dict__.update(self._loaded_structures)
self.places = 12
return
def test_write_xyz(self):
"""check writing of normal xyz file"""
stru = self.stru
stru.title = "test of writeStr"
stru.lattice = Lattice(1.0, 2.0, 3.0, 90.0, 90.0, 90.0)
stru[:] = [Atom('H', [1., 1., 1.]), Atom('Cl', [3., 2., 1.])]
filename = self.mktmpfile()
stru.write(filename, self.format)
with open(filename) as fp:
f_s = fp.read()
f_s = re.sub('[ \t]+', ' ', f_s)
s_s = "2\n%s\nH 1 2 3\nCl 3 4 3\n" % stru.title
self.assertEqual(f_s, s_s)
return
def silicon_carbide_phase():
"""Silicon Carbide 4H polytype (hexagonal, space group 186)."""
return Phase(
space_group=186,
structure=Structure(
lattice=Lattice(3.073, 3.073, 10.053, 90, 90, 120),
atoms=[
Atom(atype="Si", xyz=[0, 0, 0]),
Atom(atype="Si", xyz=[0.33, 0.667, 0.25]),
Atom(atype="C", xyz=[0, 0, 0.188]),
Atom(atype="C", xyz=[0.333, 0.667, 0.438]),
],
),
)
def test_insertAtoms(self):
"""check FitStructure.insertAtoms()
"""
from diffpy.structure import Atom
stru = self.stru
stru.read(datafile('Ni.stru'), format='pdffit')
cns = Constraint('@1')
stru.constraints['x(2)'] = cns
stru.insertAtoms(0, [Atom('Na', (0, 0, 0))])
self.assertEqual(5, len(stru))
self.assertEqual(1, len(stru.constraints))
self.assertTrue(cns is stru.constraints['x(3)'])
stru.insertAtoms(5, [Atom('Cl', (0, 0, 0))])
self.assertTrue(['x(3)'] == stru.constraints.keys())
return
def expandAsymmetricUnit(self, spacegroup, indices, sgoffset=[0,0,0]):
"""Perform symmetry expansion for atoms at given indices.
Temperature factors may be corrected to reflect the symmetry.
All constraints for expanded atoms are erased with the exception
of the occupancy("occ". Constraints of unaffected atoms are adjusted
for new positions self.initial.
spacegroup -- instance of SpaceGroup from diffpy.structure
indices -- list of integer indices of atoms to be expanded
sgoffset -- optional offset of space group origin [0,0,0]
"""
from diffpy.structure.symmetryutilities import ExpandAsymmetricUnit
acd = self._popAtomConstraints()
# get unique, reverse sorted indices
ruindices = dict.fromkeys(indices).keys()
ruindices.sort()
ruindices.reverse()
coreatoms = [self.initial[i] for i in ruindices]
corepos = [a.xyz for a in coreatoms]
coreUijs = [a.U for a in coreatoms]
eau = ExpandAsymmetricUnit(spacegroup, corepos, coreUijs,
sgoffset=sgoffset, eps=self.symposeps)
# build a nested list of new atoms:
newatoms = []
for i in range(len(coreatoms)):
ca = coreatoms[i]
caocc_con = None
if ca in acd and "occ" in acd[ca]:
caocc_con = acd[ca]["occ"]
eca = [] # expanded core atom
for j in range(eau.multiplicity[i]):
a = Atom(ca)
a.xyz = eau.expandedpos[i][j]
a.U = eau.expandedUijs[i][j]
eca.append(a)
if caocc_con is None: continue
# make a copy of occupancy constraint
acd[a] = {"occ" : copy.copy(caocc_con)}
newatoms.append(eca)
# insert new atoms where they belong
for i, atomlist in zip(ruindices, newatoms):
self.initial[i:i+1] = atomlist
# remember this spacegroup as the last one used
self.initial.pdffit["spcgr"] = spacegroup.short_name
self.initial.pdffit["sgoffset"] = list(sgoffset)
# tidy constraints
self._restoreAtomConstraints(acd)
return
def test_getvar(self):
"""check PDFStructure.getvar()
"""
from diffpy.structure import Atom
stru = self.stru
abcABG = (3.0, 4.0, 5.0, 81, 82, 83)
stru.lattice.setLatPar(*abcABG)
for i in range(6):
self.assertEqual(abcABG[i], stru.getvar('lat(%i)' % (i + 1)))
stru.append(Atom('Ni', [0.1, 0.2, 0.3]))
self.assertEqual(0.1, stru.getvar('x(1)'))
self.assertEqual(0.2, stru.getvar('y(1)'))
self.assertEqual(0.3, stru.getvar('z(1)'))
self.assertEqual(1.0, stru.getvar('occ(1)'))
# pscale
self.assertEqual(1.0, stru.getvar('pscale'))
# spdiameter
self.assertEqual(0.0, stru.getvar('spdiameter'))
stru.pdffit['spdiameter'] = 37.7
self.assertEqual(37.7, stru.getvar('spdiameter'))
# stepcut
self.assertEqual(0.0, stru.getvar('stepcut'))
stru.pdffit['stepcut'] = 17.7
self.assertEqual(17.7, stru.getvar('stepcut'))
self.assertRaises(ControlKeyError, stru.getvar, 'invalid(1)')
self.assertRaises(ControlKeyError, stru.getvar, 'invalid')
return
def _defaultNewAtom():
"""Create new atom instance with non-zero initial U.
"""
uii = 0.003
rv = Atom("C", [0.0, 0.0, 0.0],
U=[[uii, 0, 0], [0, uii, 0], [0, 0, uii]])
return rv
def _create_fcc(atom1=None, atom2=None, lattice_parameter=2.54, size=10):
"""Sets the initial positions for an FCC-like cluster.
Uses the golden ratio to create a set of evenly
spaced atom around some central point.
Parameters
_______________
atom1: str
The corner atom of the cluster
atom2: str
The edge atoms of the cluster
lattice_parameter: float
The lattice parameter of the unit cell
size: float
The size of the cluster in angstroms
Returns
------------
atom_list: list
A list of atoms in the cluster
"""
atom_list = []
x_pos, y_pos, z_pos = np.mgrid[-size:size + 1, -size:size + 1,
-size:size + 1]
x_pos = x_pos * lattice_parameter
y_pos = y_pos * lattice_parameter
z_pos = z_pos * lattice_parameter
dis = [[0, 0, 0], [.5, .5, 0], [0, .5, .5], [.5, 0, .5]]
for x, y, z in zip(x_pos.flatten(), y_pos.flatten(), z_pos.flatten()):
for d in dis:
if d == [0, 0, 0] and np.linalg.norm([x, y, z]) < size:
atom_list.append(Atom(xyz=[x, y, z], atype=atom1))
elif np.linalg.norm([
x + d[0] * lattice_parameter, y + d[1] * lattice_parameter,
z + d[2] * lattice_parameter
]) < size:
atom_list.append(
Atom(xyz=[
x + d[0] * lattice_parameter,
y + d[1] * lattice_parameter,
z + d[2] * lattice_parameter
],
atype=atom2))
else:
pass
return atom_list
def _create_bcc(atom1=None, atom2=None, lattice_parameter=2.54, size=10):
"""Sets the initial positions for an FCC-like cluster.
Uses the golden ratio to create a set of evenly
spaced atom around some central point.
Parameters
_______________
atom1: str
The corner atom of the cluster
atom2: str
The edge atoms of the cluster
lattice_parameter: float
The lattice parameter of the unit cell
size: float
The size of the cluster in angstroms
Returns
------------
atom_list: list
A list of atoms in the cluster
"""
atom_list = []
int_size = np.ceil(size / lattice_parameter)
print(int_size)
x_pos, y_pos, z_pos = np.mgrid[-int_size:(int_size + 1),
-int_size:(int_size + 1),
-int_size:(int_size + 1)]
x_pos = x_pos * lattice_parameter
y_pos = y_pos * lattice_parameter
z_pos = z_pos * lattice_parameter
for x, y, z in zip(x_pos.flatten(), y_pos.flatten(), z_pos.flatten()):
if np.linalg.norm([x, y, z]) < size:
a1 = Atom(xyz=[x, y, z], atype=atom1)
atom_list.append(a1)
if np.linalg.norm([
x + .5 * lattice_parameter, y + .5 * lattice_parameter,
z + .5 * lattice_parameter
]) < size:
a2 = Atom(xyz=[
x + 0.5 * lattice_parameter, y + 0.5 * lattice_parameter,
z + 0.5 * lattice_parameter
],
atype=atom2)
atom_list.append(a2)
return atom_list
def nickel_phase():
return Phase(
name="nickel",
space_group=225,
structure=Structure(
lattice=Lattice(3.5236, 3.5236, 3.5236, 90, 90, 90),
atoms=[Atom(xyz=[0, 0, 0], atype="Ni", Uisoequiv=0.006332)],
),
)
def test_pickling(self):
"""Test pickling of DiffpyStructureParSet.
"""
stru = Structure([Atom("C", [0, 0.2, 0.5])])
dsps = DiffpyStructureParSet("dsps", stru)
data = pickle.dumps(dsps)
dsps2 = pickle.loads(data)
self.assertEqual(1, len(dsps2.atoms))
self.assertEqual(0.2, dsps2.atoms[0].y.value)
return
def test___repr__(self):
"""Test representation of DiffpyStructureParSet objects.
"""
lat = Lattice(3, 3, 2, 90, 90, 90)
atom = Atom("C", [0, 0.2, 0.5])
stru = Structure([atom], lattice=lat)
dsps = DiffpyStructureParSet("dsps", stru)
self.assertEqual(repr(stru), repr(dsps))
self.assertEqual(repr(lat), repr(dsps.lattice))
self.assertEqual(repr(atom), repr(dsps.atoms[0]))
return
def test___init__(self):
"""check Structure.__init__()
"""
atoms = [Atom('C', [0, 0, 0]), Atom('C', [0.5, 0.5, 0.5])]
self.assertRaises(ValueError, Structure, atoms, filename=teifile)
self.assertRaises(ValueError,
Structure,
lattice=Lattice(),
filename=teifile)
self.assertRaises(ValueError,
Structure,
title='test',
filename=teifile)
stru1 = Structure(title='my title')
self.assertEqual('my title', stru1.title)
stru2a = Structure(atoms)
stru2b = Structure(iter(atoms))
stru2c = Structure(a for a in atoms)
s2a = str(stru2a)
self.assertEqual(s2a, str(stru2b))
self.assertEqual(s2a, str(stru2c))
return
def _expandAsymmetricUnit(self, block):
"""Perform symmetry expansion of self.stru using self.spacegroup.
This method updates data in stru and eau.
Parameters
----------
block : CifBlock
The top-level block containing crystal structure data.
"""
from diffpy.structure.symmetryutilities import ExpandAsymmetricUnit
corepos = [a.xyz for a in self.stru]
coreUijs = [a.U for a in self.stru]
self.eau = ExpandAsymmetricUnit(self.spacegroup,
corepos,
coreUijs,
eps=self.eps)
# setup anisotropy according to symmetry requirements
# unless it was already explicitly set
for ca, uisotropy in zip(self.stru, self.eau.Uisotropy):
if not ca.label in self.anisotropy:
ca.anisotropy = not uisotropy
self.anisotropy[ca.label] = ca.anisotropy
# build a nested list of new atoms:
newatoms = []
for i, ca in enumerate(self.stru):
eca = [] # expanded core atom
for j in range(self.eau.multiplicity[i]):
a = Atom(ca)
a.xyz = self.eau.expandedpos[i][j]
if j > 0:
a.label += '_' + str(j + 1)
if a.anisotropy:
a.U = self.eau.expandedUijs[i][j]
eca.append(a)
newatoms.append(eca)
# insert new atoms where they belong
self.stru[:] = sum(newatoms, [])
return
def test___setitem__slice(self):
"""check Structure.__setitem__() with a slice argument
"""
a = Atom("Si", (0.1, 0.2, 0.3))
lat = self.stru.lattice
self.stru[:] = [a]
a0 = self.stru[0]
self.assertEqual(1, len(self.stru))
self.assertEqual('Si', a0.element)
self.assertTrue(lat is a0.lattice)
self.assertTrue(numpy.array_equal(a.xyz, a0.xyz))
self.assertFalse(a is a0)
self.assertFalse(lat is a.lattice)
return
def test___setitem__(self):
"""check Structure.__setitem__()
"""
a = Atom("Si", (0.1, 0.2, 0.3))
lat = self.stru.lattice
self.stru[1] = a
a1 = self.stru[1]
self.assertEqual(2, len(self.stru))
self.assertEqual('Si', a1.element)
self.assertTrue(lat is a1.lattice)
self.assertTrue(numpy.array_equal(a.xyz, a1.xyz))
self.assertFalse(a is a1)
self.assertFalse(lat is a.lattice)
return
def test_append(self):
"""check Structure.append()
"""
a = Atom("Si", (0.1, 0.2, 0.3))
lat = self.stru.lattice
self.stru.append(a)
alast = self.stru[-1]
self.assertEqual(3, len(self.stru))
self.assertEqual('Si', alast.element)
self.assertTrue(lat is alast.lattice)
self.assertTrue(numpy.array_equal(a.xyz, alast.xyz))
self.assertFalse(a is alast)
self.assertFalse(lat is a.lattice)
return
def test_get_kinematical_atomic_scattering_factor(element, occupancy,
displacement_factor,
scattering_parameter,
desired_factor):
atom = Atom(atype=element,
occupancy=occupancy,
Uisoequiv=displacement_factor)
assert np.allclose(
get_kinematical_atomic_scattering_factor(
atom=atom,
scattering_parameter=scattering_parameter,
),
desired_factor,
)
def dict2atom(dictionary):
"""Get a :class:`diffpy.structure.Atom.atom` object from a dictionary.
Parameters
----------
dictionary : dict
Dictionary with atom information.
Returns
-------
Atom
"""
dictionary = copy.deepcopy(dictionary)
atom_dict = {"atype": dictionary.pop("element")}
atom_dict.update(dictionary)
return Atom(**atom_dict)
def test_writeStr_rawxyz(self):
"""check writing of normal xyz file"""
stru = self.stru
stru.title = "test of writeStr"
stru.lattice = Lattice(1.0, 2.0, 3.0, 90.0, 90.0, 90.0)
# plain version
stru[:] = [Atom('H', [1., 1., 1.])]
s1 = stru.writeStr(self.format)
s1 = re.sub('[ \t]+', ' ', s1)
s0 = "H 1 2 3\n"
# brutal raw version
stru[0].element = ""
s1 = stru.writeStr(self.format)
s0 = "1 2 3\n"
self.assertEqual(s1, s0)
return
def _crystaldata2phase(dictionary: dict) -> Phase:
"""Return a :class:`~orix.crystal_map.Phase` object from a
dictionary with EMsoft CrystalData group content.
Parameters
----------
dictionary
Dictionary with phase information.
Returns
-------
Phase
"""
# TODO: Move this to orix.io.plugins.emsoft_h5ebsd as part of v0.6
# Get list of atoms
n_atoms = dictionary["Natomtypes"]
atom_data = dictionary["AtomData"]
atom_types = dictionary["Atomtypes"]
if n_atoms == 1:
atom_types = (atom_types, ) # Make iterable
atoms = []
for i in range(n_atoms):
# TODO: Convert atom type integer to element name, like Ni for 26
atoms.append(
Atom(
atype=atom_types[i],
xyz=atom_data[:3, i],
occupancy=atom_data[3, i],
Uisoequiv=atom_data[4, i] / (8 * np.pi**2) * 1e2, # Å^-2
))
# TODO: Use space group setting
return Phase(
space_group=int(dictionary["SpaceGroupNumber"]),
structure=Structure(
lattice=Lattice(*dictionary["LatticeParameters"].T), atoms=atoms),
)
def testDiffpyStructureParSet(self):
"""Test the structure conversion."""
a1 = Atom("Cu", xyz = numpy.array([.0, .1, .2]), Uisoequiv = 0.003)
a2 = Atom("Ag", xyz = numpy.array([.3, .4, .5]), Uisoequiv = 0.002)
l = Lattice(2.5, 2.5, 2.5, 90, 90, 90)
dsstru = Structure([a1,a2], l)
# Structure makes copies
a1 = dsstru[0]
a2 = dsstru[1]
s = DiffpyStructureParSet("CuAg", dsstru)
self.assertEqual(s.name, "CuAg")
def _testAtoms():
# Check the atoms thoroughly
self.assertEqual(a1.element, s.Cu0.element)
self.assertEqual(a2.element, s.Ag0.element)
self.assertEqual(a1.Uisoequiv, s.Cu0.Uiso.getValue())
self.assertEqual(a2.Uisoequiv, s.Ag0.Uiso.getValue())
self.assertEqual(a1.Bisoequiv, s.Cu0.Biso.getValue())
self.assertEqual(a2.Bisoequiv, s.Ag0.Biso.getValue())
for i in range(1, 4):
for j in range(i, 4):
uijstru = getattr(a1, "U%i%i"%(i,j))
uij = getattr(s.Cu0, "U%i%i"%(i,j)).getValue()
uji = getattr(s.Cu0, "U%i%i"%(j,i)).getValue()
self.assertEqual(uijstru, uij)
self.assertEqual(uijstru, uji)
bijstru = getattr(a1, "B%i%i"%(i,j))
bij = getattr(s.Cu0, "B%i%i"%(i,j)).getValue()
bji = getattr(s.Cu0, "B%i%i"%(j,i)).getValue()
self.assertEqual(bijstru, bij)
self.assertEqual(bijstru, bji)
self.assertEqual(a1.xyz[0], s.Cu0.x.getValue())
self.assertEqual(a1.xyz[1], s.Cu0.y.getValue())
self.assertEqual(a1.xyz[2], s.Cu0.z.getValue())
return
def _testLattice():
# Test the lattice
self.assertEqual(dsstru.lattice.a, s.lattice.a.getValue())
self.assertEqual(dsstru.lattice.b, s.lattice.b.getValue())
self.assertEqual(dsstru.lattice.c, s.lattice.c.getValue())
self.assertEqual(dsstru.lattice.alpha, s.lattice.alpha.getValue())
self.assertEqual(dsstru.lattice.beta, s.lattice.beta.getValue())
self.assertEqual(dsstru.lattice.gamma, s.lattice.gamma.getValue())
_testAtoms()
_testLattice()
# Now change some values from the diffpy Structure
a1.xyz[1] = 0.123
a1.U11 = 0.321
a1.B32 = 0.111
dsstru.lattice.setLatPar(a=3.0, gamma=121)
_testAtoms()
_testLattice()
# Now change values from the srfit DiffpyStructureParSet
s.Cu0.x.setValue(0.456)
s.Cu0.U22.setValue(0.441)
s.Cu0.B13.setValue(0.550)
d = dsstru.lattice.dist(a1.xyz, a2.xyz)
s.lattice.b.setValue(4.6)
s.lattice.alpha.setValue(91.3)
_testAtoms()
_testLattice()
# Make sure the distance changed
self.assertNotEqual(d, dsstru.lattice.dist(a1.xyz, a2.xyz))
return
def nickel_structure():
"""A diffpy.structure with a Nickel crystal structure."""
return Structure(
atoms=[Atom("Ni", [0, 0, 0])],
lattice=Lattice(3.5236, 3.5236, 3.5236, 90, 90, 90),
)
def expandSuperCell(self, mno):
"""Perform supercell expansion for this structure and adjust
constraints for positions and lattice parameters. New lattice
parameters are multiplied and fractional coordinates divided by
corresponding multiplier. New atoms are grouped with their source
in the original cell.
mno -- tuple or list of three positive integer cell multipliers along
the a, b, c axis
"""
# check argument
if tuple(mno) == (1, 1, 1): return
if min(mno) < 1:
raise ControlValueError("mno must contain 3 positive integers")
# back to business
acd = self._popAtomConstraints()
mnofloats = numpy.array(mno[:3], dtype=float)
ijklist = [(i,j,k) for i in range(mno[0])
for j in range(mno[1]) for k in range(mno[2])]
# build a list of new atoms
newatoms = []
for a in self.initial:
for ijk in ijklist:
adup = Atom(a)
adup.xyz = (a.xyz + ijk)/mnofloats
newatoms.append(adup)
# does atom a have any constraint?
if a not in acd: continue
# add empty constraint dictionary for duplicate atom
acd[adup] = {}
for barevar, con in acd[a].iteritems():
formula = con.formula
if barevar in ("x", "y", "z"):
symidx = "xyz".index(barevar)
if ijk[symidx] != 0:
formula += " + %i" % ijk[symidx]
if mno[symidx] > 1:
formula = "(%s)/%.1f" % (formula, mno[symidx])
formula = re.sub(r'\((@\d+)\)', r'\1', formula)
# keep other formulas intact and add constraint
# for barevar of the duplicate atom
acd[adup][barevar] = Constraint(formula)
# replace original atoms with newatoms
self.initial[:] = newatoms
for ai, an in zip(self.initial, newatoms):
if an in acd:
acd[ai] = acd[an]
# and rebuild their constraints
self._restoreAtomConstraints(acd)
# take care of lattice parameters
self.initial.lattice.setLatPar(
a=mno[0]*self.initial.lattice.a,
b=mno[1]*self.initial.lattice.b,
c=mno[2]*self.initial.lattice.c )
# adjust lattice constraints if present
latvars = ( "lat(1)", "lat(2)", "lat(3)" )
for var, multiplier in zip(latvars, mno):
if var in self.constraints and multiplier > 1:
con = self.constraints[var]
formula = "%.0f*(%s)" % (multiplier, con.formula)
formula = re.sub(r'\((@\d+)\)', r'\1', formula)
con.formula = formula
return
("Lattice Constant gamma", "90.000"),
]:
phase_group.create_dataset(name,
data=np.array([data], dtype=np.dtype("S")))
yield f
gc.collect()
@pytest.fixture(params=[(
["a", "b", "c"],
[229, 207, 143],
["m-3m", "432", "3"],
["r", "g", "b"],
[Lattice()] * 3,
[[Atom()]] * 3,
)])
def phase_list(request):
names, space_groups, point_group_names, colors, lattices, atoms = request.param
# Apparently diffpy.structure don't allow iteration over a list of lattices
structures = [
Structure(lattice=lattices[i], atoms=a) for i, a in enumerate(atoms)
]
return PhaseList(
names=names,
space_groups=space_groups,
point_groups=point_group_names,
colors=colors,
structures=structures,
)
def default_structure():
"""An atomic structure represented using diffpy """
latt = Lattice(3, 3, 5, 90, 90, 120)
atom = Atom(atype="Ni", xyz=[0, 0, 0], lattice=latt)
hexagonal_structure = Structure(atoms=[atom], lattice=latt)
return hexagonal_structure
def testDiffpyStructureParSet(self):
"""Test the structure conversion."""
a1 = Atom("Cu", xyz=numpy.array([.0, .1, .2]), Uisoequiv=0.003)
a2 = Atom("Ag", xyz=numpy.array([.3, .4, .5]), Uisoequiv=0.002)
l = Lattice(2.5, 2.5, 2.5, 90, 90, 90)
dsstru = Structure([a1, a2], l)
# Structure makes copies
a1 = dsstru[0]
a2 = dsstru[1]
s = DiffpyStructureParSet("CuAg", dsstru)
self.assertEqual(s.name, "CuAg")
def _testAtoms():
# Check the atoms thoroughly
self.assertEqual(a1.element, s.Cu0.element)
self.assertEqual(a2.element, s.Ag0.element)
self.assertEqual(a1.Uisoequiv, s.Cu0.Uiso.getValue())
self.assertEqual(a2.Uisoequiv, s.Ag0.Uiso.getValue())
self.assertEqual(a1.Bisoequiv, s.Cu0.Biso.getValue())
self.assertEqual(a2.Bisoequiv, s.Ag0.Biso.getValue())
for i in range(1, 4):
for j in range(i, 4):
uijstru = getattr(a1, "U%i%i" % (i, j))
uij = getattr(s.Cu0, "U%i%i" % (i, j)).getValue()
uji = getattr(s.Cu0, "U%i%i" % (j, i)).getValue()
self.assertEqual(uijstru, uij)
self.assertEqual(uijstru, uji)
bijstru = getattr(a1, "B%i%i" % (i, j))
bij = getattr(s.Cu0, "B%i%i" % (i, j)).getValue()
bji = getattr(s.Cu0, "B%i%i" % (j, i)).getValue()
self.assertEqual(bijstru, bij)
self.assertEqual(bijstru, bji)
self.assertEqual(a1.xyz[0], s.Cu0.x.getValue())
self.assertEqual(a1.xyz[1], s.Cu0.y.getValue())
self.assertEqual(a1.xyz[2], s.Cu0.z.getValue())
return
def _testLattice():
# Test the lattice
self.assertEqual(dsstru.lattice.a, s.lattice.a.getValue())
self.assertEqual(dsstru.lattice.b, s.lattice.b.getValue())
self.assertEqual(dsstru.lattice.c, s.lattice.c.getValue())
self.assertEqual(dsstru.lattice.alpha, s.lattice.alpha.getValue())
self.assertEqual(dsstru.lattice.beta, s.lattice.beta.getValue())
self.assertEqual(dsstru.lattice.gamma, s.lattice.gamma.getValue())
_testAtoms()
_testLattice()
# Now change some values from the diffpy Structure
a1.xyz[1] = 0.123
a1.U11 = 0.321
a1.B32 = 0.111
dsstru.lattice.setLatPar(a=3.0, gamma=121)
_testAtoms()
_testLattice()
# Now change values from the srfit DiffpyStructureParSet
s.Cu0.x.setValue(0.456)
s.Cu0.U22.setValue(0.441)
s.Cu0.B13.setValue(0.550)
d = dsstru.lattice.dist(a1.xyz, a2.xyz)
s.lattice.b.setValue(4.6)
s.lattice.alpha.setValue(91.3)
_testAtoms()
_testLattice()
# Make sure the distance changed
self.assertNotEqual(d, dsstru.lattice.dist(a1.xyz, a2.xyz))
return