def __init__(self, structure, min_cell_size=1, max_cell_size=1, symm_prec=0.1, enum_precision_parameter=0.001, refine_structure=False): """ Initializes the adapter with a structure and some parameters. Args: structure: An input structure. min_cell_size (int): The minimum cell size wanted. Defaults to 1. max_cell_size (int): The maximum cell size wanted. Defaults to 1. symm_prec (float): Symmetry precision. Defaults to 0.1. enum_precision_parameter (float): Finite precision parameter for enumlib. Default of 0.001 is usually ok, but you might need to tweak it for certain cells. refine_structure (bool): If you are starting from a structure that has been relaxed via some electronic structure code, it is usually much better to start with symmetry determination and then obtain a refined structure. The refined structure have cell parameters and atomic positions shifted to the expected symmetry positions, which makes it much less sensitive precision issues in enumlib. If you are already starting from an experimental cif, refinement should have already been done and it is not necessary. Defaults to False. """ if refine_structure: finder = SymmetryFinder(structure, symm_prec) self.structure = finder.get_refined_structure() else: self.structure = structure self.min_cell_size = min_cell_size self.max_cell_size = max_cell_size self.symm_prec = symm_prec self.enum_precision_parameter = enum_precision_parameter
def test_get_refined_structure(self): for a in self.sg.get_refined_structure().lattice.angles: self.assertEqual(a, 90) refined = self.disordered_sg.get_refined_structure() for a in refined.lattice.angles: self.assertEqual(a, 90) self.assertEqual(refined.lattice.a, refined.lattice.b) parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) s = parser.get_structures()[0] sg = SymmetryFinder(s, 0.001) self.assertEqual(sg.get_refined_structure().num_sites, 4 * s.num_sites)
def test_get_refined_structure(self): for a in self.sg.get_refined_structure().lattice.angles: self.assertEqual(a, 90) refined = self.disordered_sg.get_refined_structure() for a in refined.lattice.angles: self.assertEqual(a, 90) self.assertEqual(refined.lattice.a, refined.lattice.b) parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) s = parser.get_structures()[0] sg = SymmetryFinder(s, 0.001) self.assertEqual(sg.get_refined_structure().num_sites, 4 * s.num_sites)
def get_structure(vasp_run, outcar=None, initial_structure=False, additional_info=False): """ Process structure for static calculations from previous run. Args: vasp_run: Vasprun object that contains the final structure from previous run. outcar: Outcar object that contains the magnetization info from previous run. initial_structure: Whether to return the structure from previous run. Default is False. additional_info: Whether to return additional symmetry info related to the structure. If True, return a list of the refined structure ( conventional cell), the conventional standard structure, the symmetry dataset and symmetry operations of the structure (see SymmetryFinder doc for details) Returns: Returns the magmom-decorated structure that can be passed to get Vasp input files, e.g. get_kpoints. """ #TODO: fix magmom for get_*_structures if vasp_run.is_spin: if outcar and outcar.magnetization: magmom = {"magmom": [i['tot'] for i in outcar.magnetization]} else: magmom = { "magmom": vasp_run.to_dict['input']['parameters']['MAGMOM'] } else: magmom = None structure = vasp_run.final_structure if magmom: structure = structure.copy(site_properties=magmom) sym_finder = SymmetryFinder(structure, symprec=0.01) if initial_structure: return structure elif additional_info: info = [ sym_finder.get_refined_structure(), sym_finder.get_conventional_standard_structure(), sym_finder.get_symmetry_dataset(), sym_finder.get_symmetry_operations() ] return [sym_finder.get_primitive_standard_structure(), info] else: return sym_finder.get_primitive_standard_structure()
def __init__(self, structure, min_cell_size=1, max_cell_size=1, symm_prec=0.1, enum_precision_parameter=0.001, refine_structure=False): if refine_structure: finder = SymmetryFinder(structure, symm_prec) self.structure = finder.get_refined_structure() else: self.structure = structure self.min_cell_size = min_cell_size self.max_cell_size = max_cell_size self.symm_prec = symm_prec self.enum_precision_parameter = enum_precision_parameter
def get_structure(vasp_run, outcar=None, initial_structure=False, additional_info=False): """ Process structure for static calculations from previous run. Args: vasp_run: Vasprun object that contains the final structure from previous run. outcar: Outcar object that contains the magnetization info from previous run. initial_structure: Whether to return the structure from previous run. Default is False. additional_info: Whether to return additional symmetry info related to the structure. If True, return a list of the refined structure ( conventional cell), the conventional standard structure, the symmetry dataset and symmetry operations of the structure (see SymmetryFinder doc for details) Returns: Returns the magmom-decorated structure that can be passed to get Vasp input files, e.g. get_kpoints. """ #TODO: fix magmom for get_*_structures if vasp_run.is_spin: if outcar and outcar.magnetization: magmom = {"magmom": [i['tot'] for i in outcar.magnetization]} else: magmom = { "magmom": vasp_run.to_dict['input']['parameters'] ['MAGMOM']} else: magmom = None structure = vasp_run.final_structure if magmom: structure = structure.copy(site_properties=magmom) sym_finder = SymmetryFinder(structure, symprec=0.01) if initial_structure: return structure elif additional_info: info = [sym_finder.get_refined_structure(), sym_finder.get_conventional_standard_structure(), sym_finder.get_symmetry_dataset(), sym_finder.get_symmetry_operations()] return [sym_finder.get_primitive_standard_structure(), info] else: return sym_finder.get_primitive_standard_structure()
def __init__(self, structure, min_cell_size=1, max_cell_size=1, symm_prec=0.1, enum_precision_parameter=0.001, refine_structure=False): """ Args: structure: An input structure. min_cell_size: The minimum cell size wanted. Must be an int. Defaults to 1. max_cell_size: The maximum cell size wanted. Must be an int. Defaults to 1. symm_prec: Symmetry precision. Defaults to 0.1. enum_precision_parameter: Finite precision parameter for enumlib. Default of 0.001 is usually ok, but you might need to tweak it for certain cells. refine_structure: If you are starting from a structure that has been relaxed via some electronic structure code, it is usually much better to start with symmetry determination and then obtain a refined structure. The refined structure have cell parameters and atomic positions shifted to the expected symmetry positions, which makes it much less sensitive precision issues in enumlib. If you are already starting from an experimental cif, refinment should have already been done and it is not necessary. Defaults to False. """ if refine_structure: finder = SymmetryFinder(structure, symm_prec) self.structure = finder.get_refined_structure() else: self.structure = structure self.min_cell_size = min_cell_size self.max_cell_size = max_cell_size self.symm_prec = symm_prec self.enum_precision_parameter = enum_precision_parameter
def get_xrd_data(self, structure, scaled=True, two_theta_range=(0, 90)): """ Calculates the XRD data for a structure. Args: structure (Structure): Input structure scaled (bool): Whether to return scaled intensities. The maximum peak is set to a value of 100. Defaults to True. Use False if you need the absolute values to combine XRD plots. two_theta_range ([float of length 2]): Tuple for range of two_thetas to calculate in degrees. Defaults to (0, 90). Set to None if you want all diffracted beams within the limiting sphere of radius 2 / wavelength. Returns: (XRD pattern) in the form of [[two_theta, intensity, {(h, k, l): mult}, d_hkl], ...] Two_theta is in degrees. Intensity is in arbitrary units and if scaled (the default), has a maximum value of 100 for the highest peak. {(h, k, l): mult} is a dict of Miller indices for all diffracted lattice planes contributing to that intensity and their multiplicities. d_hkl is the interplanar spacing. """ if self.symprec: finder = SymmetryFinder(structure, symprec=self.symprec) structure = finder.get_refined_structure() wavelength = self.wavelength latt = structure.lattice is_hex = latt.is_hexagonal() # Obtained from Bragg condition. Note that reciprocal lattice # vector length is 1 / d_hkl. min_r, max_r = (0, 2 / wavelength) if two_theta_range is None else \ [2 * sin(radians(t / 2)) / wavelength for t in two_theta_range] # Obtain crystallographic reciprocal lattice points within range recip_latt = latt.reciprocal_lattice_crystallographic recip_pts = recip_latt.get_points_in_sphere( [[0, 0, 0]], [0, 0, 0], max_r) if min_r: recip_pts = filter(lambda d: d[1] >= min_r, recip_pts) # Create a flattened array of zs, coeffs, fcoords and occus. This is # used to perform vectorized computation of atomic scattering factors # later. Note that these are not necessarily the same size as the # structure as each partially occupied specie occupies its own # position in the flattened array. zs = [] coeffs = [] fcoords = [] occus = [] dwfactors = [] for site in structure: for sp, occu in site.species_and_occu.items(): zs.append(sp.Z) try: c = ATOMIC_SCATTERING_PARAMS[sp.symbol] except KeyError: raise ValueError("Unable to calculate XRD pattern as " "there is no scattering coefficients for" " %s." % sp.symbol) coeffs.append(c) dwfactors.append(self.debye_waller_factors.get(sp.symbol, 0)) fcoords.append(site.frac_coords) occus.append(occu) zs = np.array(zs) coeffs = np.array(coeffs) fcoords = np.array(fcoords) occus = np.array(occus) dwfactors = np.array(dwfactors) peaks = {} two_thetas = [] for hkl, g_hkl, ind in sorted( recip_pts, key=lambda i: (i[1], -i[0][0], -i[0][1], -i[0][2])): if g_hkl != 0: d_hkl = 1 / g_hkl # Bragg condition theta = asin(wavelength * g_hkl / 2) # s = sin(theta) / wavelength = 1 / 2d = |ghkl| / 2 (d = # 1/|ghkl|) s = g_hkl / 2 #Store s^2 since we are using it a few times. s2 = s ** 2 # Vectorized computation of g.r for all fractional coords and # hkl. g_dot_r = np.dot(fcoords, np.transpose([hkl])).T[0] # Highly vectorized computation of atomic scattering factors. # Equivalent non-vectorized code is:: # # for site in structure: # el = site.specie # coeff = ATOMIC_SCATTERING_PARAMS[el.symbol] # fs = el.Z - 41.78214 * s2 * sum( # [d[0] * exp(-d[1] * s2) for d in coeff]) fs = zs - 41.78214 * s2 * np.sum( coeffs[:, :, 0] * np.exp(-coeffs[:, :, 1] * s2), axis=1) dw_correction = np.exp(-dwfactors * s2) # Structure factor = sum of atomic scattering factors (with # position factor exp(2j * pi * g.r and occupancies). # Vectorized computation. f_hkl = np.sum(fs * occus * np.exp(2j * pi * g_dot_r) * dw_correction) #Lorentz polarization correction for hkl lorentz_factor = (1 + cos(2 * theta) ** 2) / \ (sin(theta) ** 2 * cos(theta)) # Intensity for hkl is modulus square of structure factor. i_hkl = (f_hkl * f_hkl.conjugate()).real two_theta = degrees(2 * theta) if is_hex: #Use Miller-Bravais indices for hexagonal lattices. hkl = (hkl[0], hkl[1], - hkl[0] - hkl[1], hkl[2]) #Deal with floating point precision issues. ind = np.where(np.abs(np.subtract(two_thetas, two_theta)) < XRDCalculator.TWO_THETA_TOL) if len(ind[0]) > 0: peaks[two_thetas[ind[0]]][0] += i_hkl * lorentz_factor peaks[two_thetas[ind[0]]][1].append(tuple(hkl)) else: peaks[two_theta] = [i_hkl * lorentz_factor, [tuple(hkl)], d_hkl] two_thetas.append(two_theta) # Scale intensities so that the max intensity is 100. max_intensity = max([v[0] for v in peaks.values()]) data = [] for k in sorted(peaks.keys()): v = peaks[k] scaled_intensity = v[0] / max_intensity * 100 if scaled else v[0] fam = get_unique_families(v[1]) if scaled_intensity > XRDCalculator.SCALED_INTENSITY_TOL: data.append([k, scaled_intensity, fam, v[2]]) return data
def apply_transformation(self, structure, return_ranked_list=False): """ Return either a single ordered structure or a sequence of all ordered structures. Args: structure: Structure to order. return_ranked_list (bool): Whether or not multiple structures are returned. If return_ranked_list is a number, that number of structures is returned. Returns: Depending on returned_ranked list, either a transformed structure or a list of dictionaries, where each dictionary is of the form {"structure" = .... , "other_arguments"} The list of ordered structures is ranked by ewald energy / atom, if the input structure is an oxidation state decorated structure. Otherwise, it is ranked by number of sites, with smallest number of sites first. """ try: num_to_return = int(return_ranked_list) except ValueError: num_to_return = 1 if structure.is_ordered: raise ValueError("Enumeration can be carried out only on " "disordered structures!") if self.refine_structure: finder = SymmetryFinder(structure, self.symm_prec) structure = finder.get_refined_structure() contains_oxidation_state = False for sp in structure.composition.elements: if hasattr(sp, "oxi_state") and sp.oxi_state != 0: contains_oxidation_state = True break adaptor = EnumlibAdaptor(structure, min_cell_size=self.min_cell_size, max_cell_size=self.max_cell_size, symm_prec=self.symm_prec, refine_structure=False) adaptor.run() structures = adaptor.structures original_latt = structure.lattice inv_latt = np.linalg.inv(original_latt.matrix) ewald_matrices = {} all_structures = [] for s in structures: new_latt = s.lattice transformation = np.dot(new_latt.matrix, inv_latt) transformation = tuple([tuple([int(round(cell)) for cell in row]) for row in transformation]) if contains_oxidation_state: if transformation not in ewald_matrices: s_supercell = Structure.from_sites(structure.sites) s_supercell.make_supercell(transformation) ewald = EwaldSummation(s_supercell) ewald_matrices[transformation] = ewald else: ewald = ewald_matrices[transformation] energy = ewald.compute_sub_structure(s) all_structures.append({"num_sites": len(s), "energy": energy, "structure": s}) else: all_structures.append({"num_sites": len(s), "structure": s}) def sort_func(s): return s["energy"] / s["num_sites"] if contains_oxidation_state \ else s["num_sites"] self._all_structures = sorted(all_structures, key=sort_func) if return_ranked_list: return self._all_structures[0:num_to_return] else: return self._all_structures[0]["structure"]
def apply_transformation(self, structure, return_ranked_list=False): """ Return either a single ordered structure or a sequence of all ordered structures. Args: structure: Structure to order. return_ranked_list: Boolean stating whether or not multiple structures are returned. If return_ranked_list is a number, that number of structures is returned. Returns: Depending on returned_ranked list, either a transformed structure or a list of dictionaries, where each dictionary is of the form {"structure" = .... , "other_arguments"} The list of ordered structures is ranked by ewald energy / atom, if the input structure is an oxidation state decorated structure. Otherwise, it is ranked by number of sites, with smallest number of sites first. """ try: num_to_return = int(return_ranked_list) except ValueError: num_to_return = 1 if structure.is_ordered: raise ValueError("Enumeration can be carried out only on " "disordered structures!") if self.refine_structure: finder = SymmetryFinder(structure, self.symm_prec) structure = finder.get_refined_structure() contains_oxidation_state = True for sp in structure.composition.elements: if not hasattr(sp, "oxi_state"): contains_oxidation_state = False break adaptor = EnumlibAdaptor(structure, min_cell_size=self.min_cell_size, max_cell_size=self.max_cell_size, symm_prec=self.symm_prec, refine_structure=False) adaptor.run() structures = adaptor.structures original_latt = structure.lattice inv_latt = np.linalg.inv(original_latt.matrix) ewald_matrices = {} all_structures = [] for s in structures: new_latt = s.lattice transformation = np.dot(new_latt.matrix, inv_latt) transformation = tuple([ tuple([int(round(cell)) for cell in row]) for row in transformation ]) if contains_oxidation_state: if transformation not in ewald_matrices: s = Structure.from_sites(structure.sites) s.make_supercell(transformation) ewald = EwaldSummation(s) ewald_matrices[transformation] = ewald else: ewald = ewald_matrices[transformation] energy = ewald.compute_sub_structure(s) all_structures.append({ "num_sites": len(s), "energy": energy, "structure": s }) else: all_structures.append({"num_sites": len(s), "structure": s}) def sort_func(s): return s["energy"] / s["num_sites"] if contains_oxidation_state \ else s["num_sites"] self._all_structures = sorted(all_structures, key=sort_func) if return_ranked_list: return self._all_structures[0:num_to_return] else: return self._all_structures[0]["structure"]
class SymmetryFinderTest(unittest.TestCase): def setUp(self): p = Poscar.from_file(os.path.join(test_dir, 'POSCAR')) self.structure = p.structure self.sg = SymmetryFinder(self.structure, 0.001) parser = CifParser(os.path.join(test_dir, 'Li10GeP2S12.cif')) self.disordered_structure = parser.get_structures()[0] self.disordered_sg = SymmetryFinder(self.disordered_structure, 0.001) s = p.structure.copy() site = s[0] del s[0] s.append(site.species_and_occu, site.frac_coords) self.sg3 = SymmetryFinder(s, 0.001) parser = CifParser(os.path.join(test_dir, 'Graphite.cif')) graphite = parser.get_structures()[0] graphite.add_site_property("magmom", [0.1] * len(graphite)) self.sg4 = SymmetryFinder(graphite, 0.001) def test_get_space_symbol(self): self.assertEqual(self.sg.get_spacegroup_symbol(), "Pnma") self.assertEqual(self.disordered_sg.get_spacegroup_symbol(), "P4_2/nmc") self.assertEqual(self.sg3.get_spacegroup_symbol(), "Pnma") self.assertEqual(self.sg4.get_spacegroup_symbol(), "R-3m") def test_get_space_number(self): self.assertEqual(self.sg.get_spacegroup_number(), 62) self.assertEqual(self.disordered_sg.get_spacegroup_number(), 137) self.assertEqual(self.sg4.get_spacegroup_number(), 166) def test_get_hall(self): self.assertEqual(self.sg.get_hall(), '-P 2ac 2n') self.assertEqual(self.disordered_sg.get_hall(), 'P 4n 2n -1n') def test_get_pointgroup(self): self.assertEqual(self.sg.get_point_group(), 'mmm') self.assertEqual(self.disordered_sg.get_point_group(), '4/mmm') def test_get_symmetry_dataset(self): ds = self.sg.get_symmetry_dataset() self.assertEqual(ds['international'], 'Pnma') def test_get_crystal_system(self): crystal_system = self.sg.get_crystal_system() self.assertEqual('orthorhombic', crystal_system) self.assertEqual('tetragonal', self.disordered_sg.get_crystal_system()) def test_get_symmetry_operations(self): fracsymmops = self.sg.get_symmetry_operations() symmops = self.sg.get_symmetry_operations(True) self.assertEqual(len(symmops), 8) latt = self.structure.lattice for fop, op in zip(fracsymmops, symmops): for site in self.structure: newfrac = fop.operate(site.frac_coords) newcart = op.operate(site.coords) self.assertTrue(np.allclose(latt.get_fractional_coords(newcart), newfrac)) found = False newsite = PeriodicSite(site.species_and_occu, newcart, latt, coords_are_cartesian=True) for testsite in self.structure: if newsite.is_periodic_image(testsite, 1e-3): found = True break self.assertTrue(found) def test_get_refined_structure(self): for a in self.sg.get_refined_structure().lattice.angles: self.assertEqual(a, 90) refined = self.disordered_sg.get_refined_structure() for a in refined.lattice.angles: self.assertEqual(a, 90) self.assertEqual(refined.lattice.a, refined.lattice.b) parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) s = parser.get_structures()[0] sg = SymmetryFinder(s, 0.001) self.assertEqual(sg.get_refined_structure().num_sites, 4 * s.num_sites) def test_get_symmetrized_structure(self): symm_struct = self.sg.get_symmetrized_structure() for a in symm_struct.lattice.angles: self.assertEqual(a, 90) self.assertEqual(len(symm_struct.equivalent_sites), 5) symm_struct = self.disordered_sg.get_symmetrized_structure() self.assertEqual(len(symm_struct.equivalent_sites), 8) self.assertEqual(map(len, symm_struct.equivalent_sites), [16,4,8,4,2,8,8,8]) s1 = symm_struct.equivalent_sites[1][1] s2 = symm_struct[symm_struct.equivalent_indices[1][1]] self.assertEqual(s1, s2) self.assertEqual(self.sg4.get_symmetrized_structure()[0].magmom, 0.1) def test_find_primitive(self): """ F m -3 m Li2O testing of converting to primitive cell """ parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure) primitive_structure = s.find_primitive() self.assertEqual(primitive_structure.formula, "Li2 O1") # This isn't what is expected. All the angles should be 60 self.assertAlmostEqual(primitive_structure.lattice.alpha, 60) self.assertAlmostEqual(primitive_structure.lattice.beta, 60) self.assertAlmostEqual(primitive_structure.lattice.gamma, 60) self.assertAlmostEqual(primitive_structure.lattice.volume, structure.lattice.volume / 4.0) def test_get_ir_reciprocal_mesh(self): grid=self.sg.get_ir_reciprocal_mesh() self.assertEquals(len(grid), 216) self.assertAlmostEquals(grid[1][0][0], 0.1) self.assertAlmostEquals(grid[1][0][1], 0.0) self.assertAlmostEquals(grid[1][0][2], 0.0) self.assertEquals(grid[1][1], 2) def test_get_conventional_standard_structure(self): parser = CifParser(os.path.join(test_dir, 'bcc_1927.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 9.1980270633769461) self.assertAlmostEqual(conv.lattice.b, 9.1980270633769461) self.assertAlmostEqual(conv.lattice.c, 9.1980270633769461) parser = CifParser(os.path.join(test_dir, 'btet_1915.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 5.0615106678044235) self.assertAlmostEqual(conv.lattice.b, 5.0615106678044235) self.assertAlmostEqual(conv.lattice.c, 4.2327080177761687) parser = CifParser(os.path.join(test_dir, 'orci_1010.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 2.9542233922299999) self.assertAlmostEqual(conv.lattice.b, 4.6330325651443296) self.assertAlmostEqual(conv.lattice.c, 5.373703587040775) parser = CifParser(os.path.join(test_dir, 'orcc_1003.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 4.1430033493799998) self.assertAlmostEqual(conv.lattice.b, 31.437979757624728) self.assertAlmostEqual(conv.lattice.c, 3.99648651) parser = CifParser(os.path.join(test_dir, 'monoc_1028.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 117.53832420192903) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 14.033435583000625) self.assertAlmostEqual(conv.lattice.b, 3.96052850731) self.assertAlmostEqual(conv.lattice.c, 6.8743926325200002) parser = CifParser(os.path.join(test_dir, 'rhomb_1170.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 120) self.assertAlmostEqual(conv.lattice.a, 3.699919902005897) self.assertAlmostEqual(conv.lattice.b, 3.699919902005897) self.assertAlmostEqual(conv.lattice.c, 6.9779585500000003) def test_get_primitive_standard_structure(self): parser = CifParser(os.path.join(test_dir, 'bcc_1927.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 109.47122063400001) self.assertAlmostEqual(prim.lattice.beta, 109.47122063400001) self.assertAlmostEqual(prim.lattice.gamma, 109.47122063400001) self.assertAlmostEqual(prim.lattice.a, 7.9657251015812145) self.assertAlmostEqual(prim.lattice.b, 7.9657251015812145) self.assertAlmostEqual(prim.lattice.c, 7.9657251015812145) parser = CifParser(os.path.join(test_dir, 'btet_1915.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 105.015053349) self.assertAlmostEqual(prim.lattice.beta, 105.015053349) self.assertAlmostEqual(prim.lattice.gamma, 118.80658411899999) self.assertAlmostEqual(prim.lattice.a, 4.1579321075608791) self.assertAlmostEqual(prim.lattice.b, 4.1579321075608791) self.assertAlmostEqual(prim.lattice.c, 4.1579321075608791) parser = CifParser(os.path.join(test_dir, 'orci_1010.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 134.78923546600001) self.assertAlmostEqual(prim.lattice.beta, 105.856239333) self.assertAlmostEqual(prim.lattice.gamma, 91.276341676000001) self.assertAlmostEqual(prim.lattice.a, 3.8428217771014852) self.assertAlmostEqual(prim.lattice.b, 3.8428217771014852) self.assertAlmostEqual(prim.lattice.c, 3.8428217771014852) parser = CifParser(os.path.join(test_dir, 'orcc_1003.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 90) self.assertAlmostEqual(prim.lattice.beta, 90) self.assertAlmostEqual(prim.lattice.gamma, 164.985257335) self.assertAlmostEqual(prim.lattice.a, 15.854897098324196) self.assertAlmostEqual(prim.lattice.b, 15.854897098324196) self.assertAlmostEqual(prim.lattice.c, 3.99648651) parser = CifParser(os.path.join(test_dir, 'monoc_1028.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 63.579155761999999) self.assertAlmostEqual(prim.lattice.beta, 116.42084423747779) self.assertAlmostEqual(prim.lattice.gamma, 148.47965136208569) self.assertAlmostEqual(prim.lattice.a, 7.2908007159612325) self.assertAlmostEqual(prim.lattice.b, 7.2908007159612325) self.assertAlmostEqual(prim.lattice.c, 6.8743926325200002) parser = CifParser(os.path.join(test_dir, 'rhomb_1170.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 90) self.assertAlmostEqual(prim.lattice.beta, 90) self.assertAlmostEqual(prim.lattice.gamma, 120) self.assertAlmostEqual(prim.lattice.a, 3.699919902005897) self.assertAlmostEqual(prim.lattice.b, 3.699919902005897) self.assertAlmostEqual(prim.lattice.c, 6.9779585500000003)
class SymmetryFinderTest(unittest.TestCase): def setUp(self): p = Poscar.from_file(os.path.join(test_dir, 'POSCAR')) self.structure = p.structure self.sg = SymmetryFinder(self.structure, 0.001) parser = CifParser(os.path.join(test_dir, 'Li10GeP2S12.cif')) self.disordered_structure = parser.get_structures()[0] self.disordered_sg = SymmetryFinder(self.disordered_structure, 0.001) s = p.structure.copy() site = s[0] del s[0] s.append(site.species_and_occu, site.frac_coords) self.sg3 = SymmetryFinder(s, 0.001) parser = CifParser(os.path.join(test_dir, 'Graphite.cif')) graphite = parser.get_structures()[0] graphite.add_site_property("magmom", [0.1] * len(graphite)) self.sg4 = SymmetryFinder(graphite, 0.001) def test_get_space_symbol(self): self.assertEqual(self.sg.get_spacegroup_symbol(), "Pnma") self.assertEqual(self.disordered_sg.get_spacegroup_symbol(), "P4_2/nmc") self.assertEqual(self.sg3.get_spacegroup_symbol(), "Pnma") self.assertEqual(self.sg4.get_spacegroup_symbol(), "R-3m") def test_get_space_number(self): self.assertEqual(self.sg.get_spacegroup_number(), 62) self.assertEqual(self.disordered_sg.get_spacegroup_number(), 137) self.assertEqual(self.sg4.get_spacegroup_number(), 166) def test_get_hall(self): self.assertEqual(self.sg.get_hall(), '-P 2ac 2n') self.assertEqual(self.disordered_sg.get_hall(), 'P 4n 2n -1n') def test_get_pointgroup(self): self.assertEqual(self.sg.get_point_group(), 'mmm') self.assertEqual(self.disordered_sg.get_point_group(), '4/mmm') def test_get_symmetry_dataset(self): ds = self.sg.get_symmetry_dataset() self.assertEqual(ds['international'], 'Pnma') def test_get_crystal_system(self): crystal_system = self.sg.get_crystal_system() self.assertEqual('orthorhombic', crystal_system) self.assertEqual('tetragonal', self.disordered_sg.get_crystal_system()) def test_get_symmetry_operations(self): fracsymmops = self.sg.get_symmetry_operations() symmops = self.sg.get_symmetry_operations(True) self.assertEqual(len(symmops), 8) latt = self.structure.lattice for fop, op in zip(fracsymmops, symmops): for site in self.structure: newfrac = fop.operate(site.frac_coords) newcart = op.operate(site.coords) self.assertTrue( np.allclose(latt.get_fractional_coords(newcart), newfrac)) found = False newsite = PeriodicSite(site.species_and_occu, newcart, latt, coords_are_cartesian=True) for testsite in self.structure: if newsite.is_periodic_image(testsite, 1e-3): found = True break self.assertTrue(found) def test_get_refined_structure(self): for a in self.sg.get_refined_structure().lattice.angles: self.assertEqual(a, 90) refined = self.disordered_sg.get_refined_structure() for a in refined.lattice.angles: self.assertEqual(a, 90) self.assertEqual(refined.lattice.a, refined.lattice.b) parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) s = parser.get_structures()[0] sg = SymmetryFinder(s, 0.001) self.assertEqual(sg.get_refined_structure().num_sites, 4 * s.num_sites) def test_get_symmetrized_structure(self): symm_struct = self.sg.get_symmetrized_structure() for a in symm_struct.lattice.angles: self.assertEqual(a, 90) self.assertEqual(len(symm_struct.equivalent_sites), 5) symm_struct = self.disordered_sg.get_symmetrized_structure() self.assertEqual(len(symm_struct.equivalent_sites), 8) self.assertEqual(map(len, symm_struct.equivalent_sites), [16, 4, 8, 4, 2, 8, 8, 8]) s1 = symm_struct.equivalent_sites[1][1] s2 = symm_struct[symm_struct.equivalent_indices[1][1]] self.assertEqual(s1, s2) self.assertEqual(self.sg4.get_symmetrized_structure()[0].magmom, 0.1) def test_find_primitive(self): """ F m -3 m Li2O testing of converting to primitive cell """ parser = CifParser(os.path.join(test_dir, 'Li2O.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure) primitive_structure = s.find_primitive() self.assertEqual(primitive_structure.formula, "Li2 O1") # This isn't what is expected. All the angles should be 60 self.assertAlmostEqual(primitive_structure.lattice.alpha, 60) self.assertAlmostEqual(primitive_structure.lattice.beta, 60) self.assertAlmostEqual(primitive_structure.lattice.gamma, 60) self.assertAlmostEqual(primitive_structure.lattice.volume, structure.lattice.volume / 4.0) def test_get_ir_reciprocal_mesh(self): grid = self.sg.get_ir_reciprocal_mesh() self.assertEquals(len(grid), 216) self.assertAlmostEquals(grid[1][0][0], 0.1) self.assertAlmostEquals(grid[1][0][1], 0.0) self.assertAlmostEquals(grid[1][0][2], 0.0) self.assertEquals(grid[1][1], 2) def test_get_conventional_standard_structure(self): parser = CifParser(os.path.join(test_dir, 'bcc_1927.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 9.1980270633769461) self.assertAlmostEqual(conv.lattice.b, 9.1980270633769461) self.assertAlmostEqual(conv.lattice.c, 9.1980270633769461) parser = CifParser(os.path.join(test_dir, 'btet_1915.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 5.0615106678044235) self.assertAlmostEqual(conv.lattice.b, 5.0615106678044235) self.assertAlmostEqual(conv.lattice.c, 4.2327080177761687) parser = CifParser(os.path.join(test_dir, 'orci_1010.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 2.9542233922299999) self.assertAlmostEqual(conv.lattice.b, 4.6330325651443296) self.assertAlmostEqual(conv.lattice.c, 5.373703587040775) parser = CifParser(os.path.join(test_dir, 'orcc_1003.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 4.1430033493799998) self.assertAlmostEqual(conv.lattice.b, 31.437979757624728) self.assertAlmostEqual(conv.lattice.c, 3.99648651) parser = CifParser(os.path.join(test_dir, 'monoc_1028.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 117.53832420192903) self.assertAlmostEqual(conv.lattice.gamma, 90) self.assertAlmostEqual(conv.lattice.a, 14.033435583000625) self.assertAlmostEqual(conv.lattice.b, 3.96052850731) self.assertAlmostEqual(conv.lattice.c, 6.8743926325200002) parser = CifParser(os.path.join(test_dir, 'rhomb_1170.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) conv = s.get_conventional_standard_structure() self.assertAlmostEqual(conv.lattice.alpha, 90) self.assertAlmostEqual(conv.lattice.beta, 90) self.assertAlmostEqual(conv.lattice.gamma, 120) self.assertAlmostEqual(conv.lattice.a, 3.699919902005897) self.assertAlmostEqual(conv.lattice.b, 3.699919902005897) self.assertAlmostEqual(conv.lattice.c, 6.9779585500000003) def test_get_primitive_standard_structure(self): parser = CifParser(os.path.join(test_dir, 'bcc_1927.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 109.47122063400001) self.assertAlmostEqual(prim.lattice.beta, 109.47122063400001) self.assertAlmostEqual(prim.lattice.gamma, 109.47122063400001) self.assertAlmostEqual(prim.lattice.a, 7.9657251015812145) self.assertAlmostEqual(prim.lattice.b, 7.9657251015812145) self.assertAlmostEqual(prim.lattice.c, 7.9657251015812145) parser = CifParser(os.path.join(test_dir, 'btet_1915.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 105.015053349) self.assertAlmostEqual(prim.lattice.beta, 105.015053349) self.assertAlmostEqual(prim.lattice.gamma, 118.80658411899999) self.assertAlmostEqual(prim.lattice.a, 4.1579321075608791) self.assertAlmostEqual(prim.lattice.b, 4.1579321075608791) self.assertAlmostEqual(prim.lattice.c, 4.1579321075608791) parser = CifParser(os.path.join(test_dir, 'orci_1010.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 134.78923546600001) self.assertAlmostEqual(prim.lattice.beta, 105.856239333) self.assertAlmostEqual(prim.lattice.gamma, 91.276341676000001) self.assertAlmostEqual(prim.lattice.a, 3.8428217771014852) self.assertAlmostEqual(prim.lattice.b, 3.8428217771014852) self.assertAlmostEqual(prim.lattice.c, 3.8428217771014852) parser = CifParser(os.path.join(test_dir, 'orcc_1003.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 90) self.assertAlmostEqual(prim.lattice.beta, 90) self.assertAlmostEqual(prim.lattice.gamma, 164.985257335) self.assertAlmostEqual(prim.lattice.a, 15.854897098324196) self.assertAlmostEqual(prim.lattice.b, 15.854897098324196) self.assertAlmostEqual(prim.lattice.c, 3.99648651) parser = CifParser(os.path.join(test_dir, 'monoc_1028.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 63.579155761999999) self.assertAlmostEqual(prim.lattice.beta, 116.42084423747779) self.assertAlmostEqual(prim.lattice.gamma, 148.47965136208569) self.assertAlmostEqual(prim.lattice.a, 7.2908007159612325) self.assertAlmostEqual(prim.lattice.b, 7.2908007159612325) self.assertAlmostEqual(prim.lattice.c, 6.8743926325200002) parser = CifParser(os.path.join(test_dir, 'rhomb_1170.cif')) structure = parser.get_structures(False)[0] s = SymmetryFinder(structure, symprec=1e-2) prim = s.get_primitive_standard_structure() self.assertAlmostEqual(prim.lattice.alpha, 90) self.assertAlmostEqual(prim.lattice.beta, 90) self.assertAlmostEqual(prim.lattice.gamma, 120) self.assertAlmostEqual(prim.lattice.a, 3.699919902005897) self.assertAlmostEqual(prim.lattice.b, 3.699919902005897) self.assertAlmostEqual(prim.lattice.c, 6.9779585500000003)
def get_xrd_data(self, structure, scaled=True, two_theta_range=(0, 90)): """ Calculates the XRD data for a structure. Args: structure (Structure): Input structure scaled (bool): Whether to return scaled intensities. The maximum peak is set to a value of 100. Defaults to True. Use False if you need the absolute values to combine XRD plots. two_theta_range ([float of length 2]): Tuple for range of two_thetas to calculate in degrees. Defaults to (0, 90). Set to None if you want all diffracted beams within the limiting sphere of radius 2 / wavelength. Returns: (XRD pattern) in the form of [[two_theta, intensity, {(h, k, l): mult}, d_hkl], ...] Two_theta is in degrees. Intensity is in arbitrary units and if scaled (the default), has a maximum value of 100 for the highest peak. {(h, k, l): mult} is a dict of Miller indices for all diffracted lattice planes contributing to that intensity and their multiplicities. d_hkl is the interplanar spacing. """ if self.symprec: finder = SymmetryFinder(structure, symprec=self.symprec) structure = finder.get_refined_structure() wavelength = self.wavelength latt = structure.lattice is_hex = latt.is_hexagonal() # Obtained from Bragg condition. Note that reciprocal lattice # vector length is 1 / d_hkl. min_r, max_r = (0, 2 / wavelength) if two_theta_range is None else \ [2 * sin(radians(t / 2)) / wavelength for t in two_theta_range] # Obtain crystallographic reciprocal lattice points within range recip_latt = latt.reciprocal_lattice_crystallographic recip_pts = recip_latt.get_points_in_sphere([[0, 0, 0]], [0, 0, 0], max_r) if min_r: recip_pts = filter(lambda d: d[1] >= min_r, recip_pts) # Create a flattened array of zs, coeffs, fcoords and occus. This is # used to perform vectorized computation of atomic scattering factors # later. Note that these are not necessarily the same size as the # structure as each partially occupied specie occupies its own # position in the flattened array. zs = [] coeffs = [] fcoords = [] occus = [] dwfactors = [] for site in structure: for sp, occu in site.species_and_occu.items(): zs.append(sp.Z) try: c = ATOMIC_SCATTERING_PARAMS[sp.symbol] except KeyError: raise ValueError("Unable to calculate XRD pattern as " "there is no scattering coefficients for" " %s." % sp.symbol) coeffs.append(c) dwfactors.append(self.debye_waller_factors.get(sp.symbol, 0)) fcoords.append(site.frac_coords) occus.append(occu) zs = np.array(zs) coeffs = np.array(coeffs) fcoords = np.array(fcoords) occus = np.array(occus) dwfactors = np.array(dwfactors) peaks = {} two_thetas = [] for hkl, g_hkl, ind in sorted(recip_pts, key=lambda i: (i[1], -i[0][0], -i[0][1], -i[0][2])): if g_hkl != 0: d_hkl = 1 / g_hkl # Bragg condition theta = asin(wavelength * g_hkl / 2) # s = sin(theta) / wavelength = 1 / 2d = |ghkl| / 2 (d = # 1/|ghkl|) s = g_hkl / 2 #Store s^2 since we are using it a few times. s2 = s**2 # Vectorized computation of g.r for all fractional coords and # hkl. g_dot_r = np.dot(fcoords, np.transpose([hkl])).T[0] # Highly vectorized computation of atomic scattering factors. # Equivalent non-vectorized code is:: # # for site in structure: # el = site.specie # coeff = ATOMIC_SCATTERING_PARAMS[el.symbol] # fs = el.Z - 41.78214 * s2 * sum( # [d[0] * exp(-d[1] * s2) for d in coeff]) fs = zs - 41.78214 * s2 * np.sum( coeffs[:, :, 0] * np.exp(-coeffs[:, :, 1] * s2), axis=1) dw_correction = np.exp(-dwfactors * s2) # Structure factor = sum of atomic scattering factors (with # position factor exp(2j * pi * g.r and occupancies). # Vectorized computation. f_hkl = np.sum(fs * occus * np.exp(2j * pi * g_dot_r) * dw_correction) #Lorentz polarization correction for hkl lorentz_factor = (1 + cos(2 * theta) ** 2) / \ (sin(theta) ** 2 * cos(theta)) # Intensity for hkl is modulus square of structure factor. i_hkl = (f_hkl * f_hkl.conjugate()).real two_theta = degrees(2 * theta) if is_hex: #Use Miller-Bravais indices for hexagonal lattices. hkl = (hkl[0], hkl[1], -hkl[0] - hkl[1], hkl[2]) #Deal with floating point precision issues. ind = np.where( np.abs(np.subtract(two_thetas, two_theta)) < XRDCalculator.TWO_THETA_TOL) if len(ind[0]) > 0: peaks[two_thetas[ind[0]]][0] += i_hkl * lorentz_factor peaks[two_thetas[ind[0]]][1].append(tuple(hkl)) else: peaks[two_theta] = [ i_hkl * lorentz_factor, [tuple(hkl)], d_hkl ] two_thetas.append(two_theta) # Scale intensities so that the max intensity is 100. max_intensity = max([v[0] for v in peaks.values()]) data = [] for k in sorted(peaks.keys()): v = peaks[k] scaled_intensity = v[0] / max_intensity * 100 if scaled else v[0] fam = get_unique_families(v[1]) if scaled_intensity > XRDCalculator.SCALED_INTENSITY_TOL: data.append([k, scaled_intensity, fam, v[2]]) return data