"""
smact.distorter: Module for generating symmetry-unique substitutions on a given sub-lattice.
As input it takes the ASE crystal object (as built by smact.builder)
and the sub-lattice on which substitutions are to be made.
There is an example of how to use the code in Example_distort.py
TODO: Add a functionality to check two Atoms objects against one another
for equivalence.
"""
import copy
import smact
try:
from pyspglib import spglib
except ImportError:
try:
from spglib import spglib
except ImportError:
raise Exception("Could not load spglib")
from ase.spacegroup import Spacegroup
[docs]def get_sg(lattice):
"""
Get the space-group of the system.
Args:
lattice: the ASE crystal class
Returns:
sg (int): integer number of the spacegroup
"""
spacegroup = spglib.get_spacegroup(lattice, symprec=1e-5)
space_split = spacegroup.split()
spg_num = space_split[1].replace("(", "").replace(")", "")
sg = Spacegroup(int(spg_num))
return sg
[docs]def get_inequivalent_sites(sub_lattice, lattice):
"""Given a sub lattice, returns symmetry unique sites for substitutions.
Args:
sub_lattice (list of lists): array containing Cartesian coordinates
of the sub-lattice of interest
lattice (ASE crystal): the total lattice
Returns:
List of sites
"""
sg = get_sg(lattice)
inequivalent_sites = []
for site in sub_lattice:
new_site = True
# Check against the existing members of the list of inequivalent sites
if len(inequivalent_sites) > 0:
for inequiv_site in inequivalent_sites:
if smact.are_eq(site, inequiv_site) == True:
new_site = False
# Check against symmetry related members of the list of inequivalent sites
equiv_inequiv_sites, _ = sg.equivalent_sites(inequiv_site)
for equiv_inequiv_site in equiv_inequiv_sites:
if smact.are_eq(site, equiv_inequiv_site) == True:
new_site = False
if new_site == True:
inequivalent_sites.append(site)
return inequivalent_sites
[docs]def make_substitution(lattice, site, new_species):
"""Change atomic species on lattice site to new_species.
Args:
lattice (ASE crystal): Input lattice
site (list): Cartesian coordinates of the substitution site
new_species (str): New species
Returns:
lattice
"""
i = 0
# NBNBNBNB It is necessary to use deepcopy for objects, otherwise changes applied to a clone
# will also apply to the parent object.
new_lattice = copy.deepcopy(lattice)
lattice_sites = new_lattice.get_scaled_positions()
for lattice_site in lattice_sites:
if smact.are_eq(lattice_site, site):
new_lattice[i].symbol = new_species
i = i + 1
return new_lattice
[docs]def build_sub_lattice(lattice, symbol):
"""Generate a sub-lattice of the lattice based on equivalent atomic species.
Args:
lattice (ASE crystal class): Input lattice
symbol (string): Symbol of species identifying sub-lattice
Returns:
list of lists:
sub_lattice: Cartesian coordinates of the sub-lattice of symbol
"""
sub_lattice = []
i = 0
atomic_labels = lattice.get_chemical_symbols()
positions = lattice.get_scaled_positions()
for atom in atomic_labels:
if atom == symbol:
sub_lattice.append(positions[i])
i = i + 1
return sub_lattice