def mutate(self, atoms):
"""Does the actual mutation."""
N = len(atoms) if self.n_top is None else self.n_top
slab = atoms[:len(atoms) - N]
atoms = atoms[-N:]
if self.use_tags:
gather_atoms_by_tag(atoms)
tags = atoms.get_tags() if self.use_tags else np.arange(N)
pos_ref = atoms.get_positions()
num = atoms.get_atomic_numbers()
cell = atoms.get_cell()
pbc = atoms.get_pbc()
symbols = atoms.get_chemical_symbols()
unique_tags = np.unique(tags)
n = len(unique_tags)
swaps = int(np.ceil(n * self.probability / 2.))
sym = []
for tag in unique_tags:
indices = np.where(tags == tag)[0]
s = ''.join([symbols[j] for j in indices])
sym.append(s)
assert len(np.unique(sym)) > 1, \
'Permutations with one atom (or molecule) type is not valid'
count = 0
maxcount = 1000
too_close = True
while too_close and count < maxcount:
count += 1
pos = pos_ref.copy()
for _ in range(swaps):
i = j = 0
while sym[i] == sym[j]:
i = self.rng.randint(0, high=n)
j = self.rng.randint(0, high=n)
ind1 = np.where(tags == i)
ind2 = np.where(tags == j)
cop1 = np.mean(pos[ind1], axis=0)
cop2 = np.mean(pos[ind2], axis=0)
pos[ind1] += cop2 - cop1
pos[ind2] += cop1 - cop2
top = Atoms(num, positions=pos, cell=cell, pbc=pbc, tags=tags)
if self.blmin is None:
too_close = False
else:
too_close = atoms_too_close(top,
self.blmin,
use_tags=self.use_tags)
if not too_close and self.test_dist_to_slab:
too_close = atoms_too_close_two_sets(top, slab, self.blmin)
if count == maxcount:
return None
mutant = slab + top
return mutant
def mutate(self, atoms):
""" Does the actual mutation. """
slab = atoms[0:len(atoms) - self.n_top]
pos_ref = atoms.get_positions()[-self.n_top:]
num_top = atoms.numbers[-self.n_top:]
st = 2. * self.rattle_strength
count = 0
tc = True
while tc and count < 1000:
pos = pos_ref.copy()
for i in xrange(len(pos)):
if random() < self.rattle_prop:
r = np.array([random() for r in xrange(3)])
pos[i] = pos[i] + st * (r - 0.5)
top = Atoms(num_top,
positions=pos,
cell=slab.get_cell(),
pbc=slab.get_pbc())
tc = atoms_too_close(top, self.blmin)
if not tc:
tc = atoms_too_close_two_sets(top, slab, self.blmin)
count += 1
if count == 1000:
return None
tot = slab + top
return tot
def mutate(self, atoms):
"""Does the actual mutation."""
N = len(atoms) if self.n_top is None else self.n_top
slab = atoms[:len(atoms) - N]
atoms = atoms[-N:]
tags = atoms.get_tags() if self.use_tags else np.arange(N)
pos_ref = atoms.get_positions()
num = atoms.get_atomic_numbers()
cell = atoms.get_cell()
pbc = atoms.get_pbc()
st = 2. * self.rattle_strength
count = 0
maxcount = 1000
too_close = True
while too_close and count < maxcount:
count += 1
pos = pos_ref.copy()
ok = False
for tag in np.unique(tags):
select = np.where(tags == tag)
if self.rng.rand() < self.rattle_prop:
ok = True
r = self.rng.rand(3)
pos[select] += st * (r - 0.5)
if not ok:
# Nothing got rattled
continue
top = Atoms(num, positions=pos, cell=cell, pbc=pbc, tags=tags)
too_close = atoms_too_close(top,
self.blmin,
use_tags=self.use_tags)
if not too_close and self.test_dist_to_slab:
too_close = atoms_too_close_two_sets(top, slab, self.blmin)
if count == maxcount:
return None
mutant = slab + top
return mutant
def mutate(self, atoms):
""" Does the actual mutation. """
slab = atoms[0:len(atoms) - self.n_top]
pos_ref = atoms.get_positions()[-self.n_top:]
num_top = atoms.numbers[-self.n_top:]
st = 2. * self.rattle_strength
count = 0
tc = True
while tc and count < 1000:
pos = pos_ref.copy()
for i in xrange(len(pos)):
if random() < self.rattle_prop:
r = np.array([random() for r in xrange(3)])
pos[i] = pos[i] + st * (r - 0.5)
top = Atoms(num_top, positions=pos,
cell=slab.get_cell(), pbc=slab.get_pbc())
tc = atoms_too_close(top, self.blmin)
if not tc:
tc = atoms_too_close_two_sets(top, slab, self.blmin)
count += 1
if count == 1000:
return None, 'rattle'
tot = slab + top
return tot
pairing = CutAndSplicePairing(slab, n_top, cd)
c3, desc = pairing.get_new_individual([c1, c2])
# verify that the stoichiometry is preserved
assert np.all(c3.numbers == c1.numbers)
top1 = c1[-n_top:]
top2 = c2[-n_top:]
top3 = c3[-n_top:]
# verify that the positions in the new candidate come from c1 or c2
n1 = -1 * np.ones((n_top,))
n2 = -1 * np.ones((n_top,))
for i in range(n_top):
for j in range(n_top):
if np.all(top1.positions[j, :] == top3.positions[i, :]):
n1[i] = j
break
elif np.all(top2.positions[j, :] == top3.positions[i, :]):
n2[i] = j
break
assert (n1[i] > -1 and n2[i] == -1) or (n1[i] == -1 and n2[i] > -1)
# verify that c3 includes atoms from both c1 and c2
assert len(n1[n1 > -1]) > 0 and len(n2[n2 > -1]) > 0
# verify no atoms too close
assert not atoms_too_close(top3, cd)
def mutate(self, atoms):
""" Does the actual mutation. """
cell_ref = atoms.get_cell()
pos_ref = atoms.get_positions()
vol_ref = atoms.get_volume()
if self.use_tags:
tags = atoms.get_tags()
gather_atoms_by_tag(atoms)
pos = atoms.get_positions()
mutant = atoms.copy()
count = 0
too_close = True
maxcount = 1000
while too_close and count < maxcount:
count += 1
# generating the strain matrix:
strain = np.identity(3)
for i in range(self.number_of_variable_cell_vectors):
for j in range(i + 1):
r = self.rng.normal(loc=0., scale=self.stddev)
if i == j:
strain[i, j] += r
else:
epsilon = 0.5 * r
strain[i, j] += epsilon
strain[j, i] += epsilon
# applying the strain:
cell_new = np.dot(strain, cell_ref)
# convert to lower triangular form
cell_new = convert_cell(cell_new)[0].T
# volume scaling:
if self.number_of_variable_cell_vectors > 0:
volume = abs(np.linalg.det(cell_new))
if self.scaling_volume is None:
# The scaling_volume has not been set (yet),
# so we give it the same volume as the parent
scaling = vol_ref / volume
else:
scaling = self.scaling_volume / volume
scaling **= 1. / self.number_of_variable_cell_vectors
cell_new[:self.number_of_variable_cell_vectors] *= scaling
# check cell dimensions:
if not self.cellbounds.is_within_bounds(cell_new):
continue
# ensure non-variable cell vectors are indeed unchanged
for i in range(self.number_of_variable_cell_vectors, 3):
assert np.allclose(cell_new[i], cell_ref[i])
# apply the new unit cell and scale
# the atomic positions accordingly
mutant.set_cell(cell_ref, scale_atoms=False)
if self.use_tags:
transfo = np.linalg.solve(cell_ref, cell_new)
for tag in np.unique(tags):
select = np.where(tags == tag)
cop = np.mean(pos[select], axis=0)
disp = np.dot(cop, transfo) - cop
mutant.positions[select] += disp
else:
mutant.set_positions(pos_ref)
mutant.set_cell(cell_new, scale_atoms=not self.use_tags)
mutant.wrap()
# check the interatomic distances
too_close = atoms_too_close(mutant,
self.blmin,
use_tags=self.use_tags)
if count == maxcount:
mutant = None
return mutant
def test_bulk_operators():
h2 = Atoms('H2', positions=[[0, 0, 0], [0, 0, 0.75]])
blocks = [('H', 4), ('H2O', 3), (h2, 2)] # the building blocks
volume = 40. * sum([x[1] for x in blocks]) # cell volume in angstrom^3
splits = {(2,): 1, (1,): 1} # cell splitting scheme
stoichiometry = []
for block, count in blocks:
if type(block) == str:
stoichiometry += list(Atoms(block).numbers) * count
else:
stoichiometry += list(block.numbers) * count
atom_numbers = list(set(stoichiometry))
blmin = closest_distances_generator(atom_numbers=atom_numbers,
ratio_of_covalent_radii=1.3)
cellbounds = CellBounds(bounds={'phi': [30, 150], 'chi': [30, 150],
'psi': [30, 150], 'a': [3, 50],
'b': [3, 50], 'c': [3, 50]})
sg = StartGenerator(blocks, blmin, volume, cellbounds=cellbounds,
splits=splits)
# Generate 2 candidates
a1 = sg.get_new_candidate()
a1.info['confid'] = 1
a2 = sg.get_new_candidate()
a2.info['confid'] = 2
# Define and test genetic operators
pairing = CutAndSplicePairing(blmin, p1=1., p2=0., minfrac=0.15,
cellbounds=cellbounds, use_tags=True)
a3, desc = pairing.get_new_individual([a1, a2])
cell = a3.get_cell()
assert cellbounds.is_within_bounds(cell)
assert not atoms_too_close(a3, blmin, use_tags=True)
n_top = len(a1)
strainmut = StrainMutation(blmin, stddev=0.7, cellbounds=cellbounds,
use_tags=True)
softmut = SoftMutation(blmin, bounds=[2., 5.], used_modes_file=None,
use_tags=True)
rotmut = RotationalMutation(blmin, fraction=0.3, min_angle=0.5 * np.pi)
rattlemut = RattleMutation(blmin, n_top, rattle_prop=0.3, rattle_strength=0.5,
use_tags=True, test_dist_to_slab=False)
rattlerotmut = RattleRotationalMutation(rattlemut, rotmut)
permut = PermutationMutation(n_top, probability=0.33, test_dist_to_slab=False,
use_tags=True, blmin=blmin)
combmut = CombinationMutation(rattlemut, rotmut, verbose=True)
mutations = [strainmut, softmut, rotmut,
rattlemut, rattlerotmut, permut, combmut]
for i, mut in enumerate(mutations):
a = [a1, a2][i % 2]
a3 = None
while a3 is None:
a3, desc = mut.get_new_individual([a])
cell = a3.get_cell()
assert cellbounds.is_within_bounds(cell)
assert np.all(a3.numbers == a.numbers)
assert not atoms_too_close(a3, blmin, use_tags=True)
modes_file = 'modes.txt'
softmut_with = SoftMutation(blmin, bounds=[2., 5.], use_tags=True,
used_modes_file=modes_file)
no_muts = 3
for _ in range(no_muts):
softmut_with.get_new_individual([a1])
softmut_with.read_used_modes(modes_file)
assert len(list(softmut_with.used_modes.values())[0]) == no_muts
os.remove(modes_file)
comparator = OFPComparator(recalculate=True)
gold = bulk('Au') * (2, 2, 2)
assert comparator.looks_like(gold, gold)
# This move should not exceed the default threshold
gc = gold.copy()
gc[0].x += .1
assert comparator.looks_like(gold, gc)
# An additional step will exceed the threshold
gc[0].x += .2
assert not comparator.looks_like(gold, gc)
def test_film_operators(seed):
from ase.ga.startgenerator import StartGenerator
from ase.ga.cutandsplicepairing import CutAndSplicePairing
from ase.ga.standardmutations import StrainMutation
from ase.ga.utilities import (closest_distances_generator, atoms_too_close,
CellBounds)
import numpy as np
from ase import Atoms
from ase.build import molecule
# set up the random number generator
rng = np.random.RandomState(seed)
slab = Atoms('', cell=(0, 0, 15), pbc=[True, True, False])
cation, anion = 'Mg', molecule('OH')
d_oh = anion.get_distance(0, 1)
blocks = [(cation, 4), (anion, 8)]
n_top = 4 + 8 * len(anion)
use_tags = True
num_vcv = 2
box_volume = 8. * n_top
blmin = closest_distances_generator(atom_numbers=[1, 8, 12],
ratio_of_covalent_radii=0.6)
cellbounds = CellBounds(
bounds={
'phi': [0.1 * 180., 0.9 * 180.],
'chi': [0.1 * 180., 0.9 * 180.],
'psi': [0.1 * 180., 0.9 * 180.],
'a': [2, 8],
'b': [2, 8]
})
box_to_place_in = [[None, None, 3.], [None, None, [0., 0., 5.]]]
sg = StartGenerator(slab,
blocks,
blmin,
box_volume=box_volume,
splits={(2, 1): 1},
box_to_place_in=box_to_place_in,
number_of_variable_cell_vectors=num_vcv,
cellbounds=cellbounds,
test_too_far=True,
test_dist_to_slab=False,
rng=rng)
parents = []
for i in range(2):
a = None
while a is None:
a = sg.get_new_candidate()
a.info['confid'] = i
parents.append(a)
assert len(a) == n_top
assert len(np.unique(a.get_tags())) == 4 + 8
assert np.allclose(a.get_pbc(), slab.get_pbc())
p = a.get_positions()
assert np.min(p[:, 2]) > 3. - 0.5 * d_oh
assert np.max(p[:, 2]) < 3. + 5. + 0.5 * d_oh
assert not atoms_too_close(a, blmin, use_tags=use_tags)
c = a.get_cell()
assert np.allclose(c[2], slab.get_cell()[2])
assert cellbounds.is_within_bounds(c)
v = a.get_volume() * 5. / 15.
assert abs(v - box_volume) < 1e-5
# Test cut-and-splice pairing and strain mutation
pairing = CutAndSplicePairing(slab,
n_top,
blmin,
number_of_variable_cell_vectors=num_vcv,
p1=1.,
p2=0.,
minfrac=0.15,
cellbounds=cellbounds,
use_tags=use_tags,
rng=rng)
strainmut = StrainMutation(blmin,
cellbounds=cellbounds,
number_of_variable_cell_vectors=num_vcv,
use_tags=use_tags,
rng=rng)
strainmut.update_scaling_volume(parents)
for operator in [pairing, strainmut]:
child = None
while child is None:
child, desc = operator.get_new_individual(parents)
assert not atoms_too_close(child, blmin, use_tags=use_tags)
cell = child.get_cell()
assert cellbounds.is_within_bounds(cell)
assert np.allclose(cell[2], slab.get_cell()[2])
def test_cutandsplicepairing(seed):
from ase.ga.startgenerator import StartGenerator
from ase.ga.utilities import closest_distances_generator, atoms_too_close
from ase.ga.cutandsplicepairing import CutAndSplicePairing
import numpy as np
from ase.build import fcc111
from ase.constraints import FixAtoms
# set up the random number generator
rng = np.random.RandomState(seed)
# first create two random starting candidates
slab = fcc111('Au', size=(4, 4, 2), vacuum=10.0, orthogonal=True)
slab.set_constraint(FixAtoms(mask=slab.positions[:, 2] <= 10.))
pos = slab.get_positions()
cell = slab.get_cell()
p0 = np.array([0., 0., max(pos[:, 2]) + 2.])
v1 = cell[0, :] * 0.8
v2 = cell[1, :] * 0.8
v3 = cell[2, :]
v3[2] = 3.
blmin = closest_distances_generator(atom_numbers=[47, 79],
ratio_of_covalent_radii=0.7)
atom_numbers = 2 * [47] + 2 * [79]
sg = StartGenerator(slab=slab,
blocks=atom_numbers,
blmin=blmin,
box_to_place_in=[p0, [v1, v2, v3]],
rng=rng)
c1 = sg.get_new_candidate()
c1.info['confid'] = 1
c2 = sg.get_new_candidate()
c2.info['confid'] = 2
n_top = len(atom_numbers)
pairing = CutAndSplicePairing(slab, n_top, blmin, rng=rng)
c3, desc = pairing.get_new_individual([c1, c2])
# verify that the stoichiometry is preserved
assert np.all(c3.numbers == c1.numbers)
top1 = c1[-n_top:]
top2 = c2[-n_top:]
top3 = c3[-n_top:]
# verify that the positions in the new candidate come from c1 or c2
n1 = -1 * np.ones((n_top, ))
n2 = -1 * np.ones((n_top, ))
for i in range(n_top):
for j in range(n_top):
if np.allclose(top1.positions[j, :], top3.positions[i, :], 1e-12):
n1[i] = j
break
elif np.allclose(top2.positions[j, :], top3.positions[i, :],
1e-12):
n2[i] = j
break
assert (n1[i] > -1 and n2[i] == -1) or (n1[i] == -1 and n2[i] > -1)
# verify that c3 includes atoms from both c1 and c2
assert len(n1[n1 > -1]) > 0 and len(n2[n2 > -1]) > 0
# verify no atoms too close
assert not atoms_too_close(top3, blmin)
def get_new_candidate(self, maxiter=None):
"""Returns a new candidate.
maxiter: upper bound on the total number of times
the random position generator is called
when generating the new candidate.
By default (maxiter=None) no such bound
is imposed. If the generator takes too
long time to create a new candidate, it
may be suitable to specify a finite value.
When the bound is exceeded, None is returned.
"""
pbc = self.slab.get_pbc()
# Choose cell splitting
r = self.rng.rand()
cumprob = 0
for split, prob in self.splits.items():
cumprob += prob
if cumprob > r:
break
# Choose direction(s) along which to split
# and by how much
directions = [i for i in range(3) if pbc[i]]
repeat = [1, 1, 1]
if len(directions) > 0:
for number in split:
d = self.rng.choice(directions)
repeat[d] = number
repeat = tuple(repeat)
# Generate the 'full' unit cell
# for the eventual candidates
cell = self.generate_unit_cell(repeat)
if self.number_of_variable_cell_vectors == 0:
assert np.allclose(cell, self.slab.get_cell())
# Make the smaller 'box' in which we are
# allowed to place the atoms and which will
# then be repeated to fill the 'full' unit cell
box = np.copy(cell)
for i in range(self.number_of_variable_cell_vectors, 3):
box[i] = np.array(self.box_to_place_in[1][i])
box /= np.array([repeat]).T
# Here we gather the (reduced) number of blocks
# to put in the smaller box, and the 'surplus'
# occurring when the block count is not divisible
# by the number of repetitions.
# E.g. if we have a ('Ti', 4) block and do a
# [2, 3, 1] repetition, we employ a ('Ti', 1)
# block in the smaller box and delete 2 out 6
# Ti atoms afterwards
nrep = int(np.prod(repeat))
blocks, ids, surplus = [], [], []
for i, (block, count) in enumerate(self.blocks):
count_part = int(np.ceil(count * 1. / nrep))
blocks.extend([block] * count_part)
surplus.append(nrep * count_part - count)
ids.extend([i] * count_part)
N_blocks = len(blocks)
# Shuffle the ordering so different blocks
# are added in random order
order = np.arange(N_blocks)
self.rng.shuffle(order)
blocks = [blocks[i] for i in order]
ids = np.array(ids)[order]
# Add blocks one by one until we have found
# a valid candidate
blmin = self.blmin
blmin_too_far = {key: 2 * val for key, val in blmin.items()}
niter = 0
while maxiter is None or niter < maxiter:
cand = Atoms('', cell=box, pbc=pbc)
for i in range(N_blocks):
atoms = blocks[i].copy()
atoms.set_tags(i)
atoms.set_pbc(pbc)
atoms.set_cell(box, scale_atoms=False)
while maxiter is None or niter < maxiter:
niter += 1
cop = atoms.get_positions().mean(axis=0)
pos = np.dot(self.rng.rand(1, 3), box)
atoms.translate(pos - cop)
if len(atoms) > 1:
# Apply a random rotation to multi-atom blocks
phi, theta, psi = 360 * self.rng.rand(3)
atoms.euler_rotate(phi=phi,
theta=0.5 * theta,
psi=psi,
center=pos)
if not atoms_too_close_two_sets(cand, atoms, blmin):
cand += atoms
break
else:
# Reached maximum iteration number
# Break out of the for loop above
cand = None
break
if cand is None:
# Exit the main while loop
break
# Rebuild the candidate after repeating,
# randomly deleting surplus blocks and
# sorting back to the original order
cand_full = cand.repeat(repeat)
tags_full = cand_full.get_tags()
for i in range(nrep):
tags_full[len(cand) * i:len(cand) * (i + 1)] += i * N_blocks
cand_full.set_tags(tags_full)
cand = Atoms('', cell=cell, pbc=pbc)
ids_full = np.tile(ids, nrep)
tag_counter = 0
if len(self.slab) > 0:
tag_counter = int(max(self.slab.get_tags())) + 1
for i, (block, count) in enumerate(self.blocks):
tags = np.where(ids_full == i)[0]
bad = self.rng.choice(tags, size=surplus[i], replace=False)
for tag in tags:
if tag not in bad:
select = [a.index for a in cand_full if a.tag == tag]
atoms = cand_full[select] # is indeed a copy!
atoms.set_tags(tag_counter)
assert len(atoms) == len(block)
cand += atoms
tag_counter += 1
for i in range(self.number_of_variable_cell_vectors, 3):
cand.positions[:, i] += self.box_to_place_in[0][i]
# By construction, the minimal interatomic distances
# within the structure should already be respected
assert not atoms_too_close(cand, blmin, use_tags=True), \
'This is not supposed to happen; please report this bug'
if self.test_dist_to_slab and len(self.slab) > 0:
if atoms_too_close_two_sets(self.slab, cand, blmin):
continue
if self.test_too_far:
tags = cand.get_tags()
for tag in np.unique(tags):
too_far = True
indices_i = np.where(tags == tag)[0]
indices_j = np.where(tags != tag)[0]
too_far = not atoms_too_close_two_sets(
cand[indices_i], cand[indices_j], blmin_too_far)
if too_far and len(self.slab) > 0:
# the block is too far from the rest
# but might still be sufficiently
# close to the slab
too_far = not atoms_too_close_two_sets(
cand[indices_i], self.slab, blmin_too_far)
if too_far:
break
else:
too_far = False
if too_far:
continue
# Passed all the tests
cand = self.slab + cand
cand.set_cell(cell, scale_atoms=False)
break
else:
# Reached max iteration count in the while loop
return None
return cand
def mutate(self, atoms):
""" Does the actual mutation. """
cell_ref = atoms.get_cell()
pos_ref = atoms.get_positions()
vol = atoms.get_volume()
if self.use_tags:
tags = atoms.get_tags()
gather_atoms_by_tag(atoms)
pos = atoms.get_positions()
mutant = atoms.copy()
if self.cellbounds is not None:
if not self.cellbounds.is_within_bounds(cell_ref):
niggli_reduce(mutant)
count = 0
too_close = True
maxcount = 1000
while too_close and count < maxcount:
mutant.set_cell(cell_ref, scale_atoms=False)
mutant.set_positions(pos_ref)
# generating the strain matrix:
strain = np.identity(3)
for i in range(3):
for j in range(i + 1):
if i == j:
strain[i, j] += gauss(0, self.stddev)
else:
epsilon = 0.5 * gauss(0, self.stddev)
strain[i, j] += epsilon
strain[j, i] += epsilon
# applying the strain:
cell_new = np.dot(strain, cell_ref)
# volume scaling:
v = abs(np.linalg.det(cell_new))
if self.scaling_volume is None:
cell_new *= (vol / v)**(1. / 3)
else:
cell_new *= (self.scaling_volume / v)**(1. / 3)
# check cell dimensions:
if not self.cellbounds.is_within_bounds(cell_new):
continue
if self.use_tags:
transfo = np.linalg.solve(cell_ref, cell_new)
for tag in np.unique(tags):
select = np.where(tags == tag)
cop = np.mean(pos[select], axis=0)
disp = np.dot(cop, transfo) - cop
mutant.positions[select] += disp
mutant.set_cell(cell_new, scale_atoms=not self.use_tags)
# check distances:
too_close = atoms_too_close(mutant,
self.blmin,
use_tags=self.use_tags)
count += 1
if count == maxcount:
mutant = None
return mutant
def mutate(self, atoms):
""" Does the actual mutation. """
a = atoms.copy()
if inspect.isclass(self.calc):
assert issubclass(self.calc, PairwiseHarmonicPotential)
calc = self.calc(atoms, rcut=self.rcut)
else:
calc = self.calc
a.set_calculator(calc)
if self.use_tags:
a = TagFilter(a)
pos = a.get_positions()
modes = self._calculate_normal_modes(a)
# Select the mode along which we want to move the atoms;
# The first 3 translational modes as well as previously
# applied modes are discarded.
keys = np.array(sorted(modes))
index = 3
confid = atoms.info['confid']
if confid in self.used_modes:
while index in self.used_modes[confid]:
index += 1
self.used_modes[confid].append(index)
else:
self.used_modes[confid] = [index]
if self.used_modes_file is not None:
self.write_used_modes(self.used_modes_file)
key = keys[index]
mode = modes[key].reshape(np.shape(pos))
# Find a suitable amplitude for translation along the mode;
# at every trial amplitude both positive and negative
# directions are tried.
mutant = atoms.copy()
amplitude = 0.
increment = 0.1
direction = 1
largest_norm = np.max(np.apply_along_axis(np.linalg.norm, 1, mode))
def expand(atoms, positions):
if isinstance(atoms, TagFilter):
a.set_positions(positions)
return a.atoms.get_positions()
else:
return positions
while amplitude * largest_norm < self.bounds[1]:
pos_new = pos + direction * amplitude * mode
pos_new = expand(a, pos_new)
mutant.set_positions(pos_new)
mutant.wrap()
too_close = atoms_too_close(mutant,
self.blmin,
use_tags=self.use_tags)
if too_close:
amplitude -= increment
pos_new = pos + direction * amplitude * mode
pos_new = expand(a, pos_new)
mutant.set_positions(pos_new)
mutant.wrap()
break
if direction == 1:
direction = -1
else:
direction = 1
amplitude += increment
if amplitude * largest_norm < self.bounds[0]:
mutant = None
return mutant
def mutate(self, atoms):
""" Do the mutation of the atoms input. """
reflect = self.reflect
tc = True
slab = atoms[0:len(atoms) - self.n_top]
top = atoms[len(atoms) - self.n_top:len(atoms)]
num = top.numbers
unique_types = list(set(num))
nu = dict()
for u in unique_types:
nu[u] = sum(num == u)
n_tries = 1000
counter = 0
changed = False
while tc and counter < n_tries:
counter += 1
cand = top.copy()
pos = cand.get_positions()
cm = np.average(top.get_positions(), axis=0)
# first select a randomly oriented cutting plane
theta = pi * random()
phi = 2. * pi * random()
n = (cos(phi) * sin(theta), sin(phi) * sin(theta), cos(theta))
n = np.array(n)
# Calculate all atoms signed distance to the cutting plane
D = []
for (i, p) in enumerate(pos):
d = np.dot(p - cm, n)
D.append((i, d))
# Sort the atoms by their signed distance
D.sort(key=lambda x: x[1])
nu_taken = dict()
# Select half of the atoms needed for a full cluster
p_use = []
n_use = []
for (i, d) in D:
if num[i] not in nu_taken.keys():
nu_taken[num[i]] = 0
if nu_taken[num[i]] < nu[num[i]] / 2.:
p_use.append(pos[i])
n_use.append(num[i])
nu_taken[num[i]] += 1
# calculate the mirrored position and add these.
pn = []
for p in p_use:
pt = p - 2. * np.dot(p - cm, n) * n
if reflect:
pt = -pt + 2 * cm + 2 * n * np.dot(pt - cm, n)
pn.append(pt)
n_use.extend(n_use)
p_use.extend(pn)
# In the case of an uneven number of
# atoms we need to add one extra
for n in nu.keys():
if nu[n] % 2 == 0:
continue
while sum(n_use == n) > nu[n]:
for i in xrange(int(len(n_use) / 2), len(n_use)):
if n_use[i] == n:
del p_use[i]
del n_use[i]
break
assert sum(n_use == n) == nu[n]
# Make sure we have the correct number of atoms
# and rearrange the atoms so they are in the right order
for i in xrange(len(n_use)):
if num[i] == n_use[i]:
continue
for j in xrange(i + 1, len(n_use)):
if n_use[j] == num[i]:
tn = n_use[i]
tp = p_use[i]
n_use[i] = n_use[j]
p_use[i] = p_use[j]
p_use[j] = tp
n_use[j] = tn
# Finally we check that nothing is too close in the end product.
cand = Atoms(num, p_use, cell=slab.get_cell(), pbc=slab.get_pbc())
tc = atoms_too_close(cand, self.blmin)
if tc:
continue
tc = atoms_too_close_two_sets(slab, cand, self.blmin)
if not changed and counter > int(n_tries / 2):
reflect = not reflect
changed = True
tot = slab + cand
if counter == n_tries:
return None
return tot
n_top = len(atom_numbers)
pairing = CutAndSplicePairing(slab, n_top, cd)
c3, desc = pairing.get_new_individual([c1, c2])
# verify that the stoichiometry is preserved
assert np.all(c3.numbers == c1.numbers)
top1 = c1[-n_top:]
top2 = c2[-n_top:]
top3 = c3[-n_top:]
# verify that the positions in the new candidate come from c1 or c2
n1 = -1 * np.ones((n_top, ))
n2 = -1 * np.ones((n_top, ))
for i in range(n_top):
for j in range(n_top):
if np.all(top1.positions[j, :] == top3.positions[i, :]):
n1[i] = j
break
elif np.all(top2.positions[j, :] == top3.positions[i, :]):
n2[i] = j
break
assert (n1[i] > -1 and n2[i] == -1) or (n1[i] == -1 and n2[i] > -1)
# verify that c3 includes atoms from both c1 and c2
assert len(n1[n1 > -1]) > 0 and len(n2[n2 > -1]) > 0
# verify no atoms too close
assert not atoms_too_close(top3, cd)
def cross(self, a1, a2):
"""Crosses the two atoms objects and returns one"""
if len(a1) != len(self.slab) + self.n_top:
raise ValueError('Wrong size of structure to optimize')
if len(a1) != len(a2):
raise ValueError('The two structures do not have the same length')
N = self.n_top
# Only consider the atoms to optimize
a1 = a1[len(a1) - N:len(a1)]
a2 = a2[len(a2) - N:len(a2)]
if not np.array_equal(a1.numbers, a2.numbers):
err = 'Trying to pair two structures with different stoichiometry'
raise ValueError(err)
if self.use_tags and not np.array_equal(a1.get_tags(), a2.get_tags()):
err = 'Trying to pair two structures with different tags'
raise ValueError(err)
cell1 = a1.get_cell()
cell2 = a2.get_cell()
for i in range(self.number_of_variable_cell_vectors, 3):
err = 'Unit cells are supposed to be identical in direction %d'
assert np.allclose(cell1[i], cell2[i]), (err % i, cell1, cell2)
invalid = True
counter = 0
maxcount = 1000
a1_copy = a1.copy()
a2_copy = a2.copy()
# Run until a valid pairing is made or maxcount pairings are tested.
while invalid and counter < maxcount:
counter += 1
newcell = self.generate_unit_cell(cell1, cell2)
if newcell is None:
# No valid unit cell could be generated.
# This strongly suggests that it is near-impossible
# to generate one from these parent cells and it is
# better to abort now.
break
# Choose direction of cutting plane normal
if self.number_of_variable_cell_vectors == 0:
# Will be generated entirely at random
theta = np.pi * self.rng.rand()
phi = 2. * np.pi * self.rng.rand()
cut_n = np.array([
np.cos(phi) * np.sin(theta),
np.sin(phi) * np.sin(theta),
np.cos(theta)
])
else:
# Pick one of the 'variable' cell vectors
cut_n = self.rng.choice(self.number_of_variable_cell_vectors)
# Randomly translate parent structures
for a_copy, a in zip([a1_copy, a2_copy], [a1, a2]):
a_copy.set_positions(a.get_positions())
cell = a_copy.get_cell()
for i in range(self.number_of_variable_cell_vectors):
r = self.rng.rand()
cond1 = i == cut_n and r < self.p1
cond2 = i != cut_n and r < self.p2
if cond1 or cond2:
a_copy.positions += self.rng.rand() * cell[i]
if self.use_tags:
# For correct determination of the center-
# of-position of the multi-atom blocks,
# we need to group their constituent atoms
# together
gather_atoms_by_tag(a_copy)
else:
a_copy.wrap()
# Generate the cutting point in scaled coordinates
cosp1 = np.average(a1_copy.get_scaled_positions(), axis=0)
cosp2 = np.average(a2_copy.get_scaled_positions(), axis=0)
cut_p = np.zeros((1, 3))
for i in range(3):
if i < self.number_of_variable_cell_vectors:
cut_p[0, i] = self.rng.rand()
else:
cut_p[0, i] = 0.5 * (cosp1[i] + cosp2[i])
# Perform the pairing:
child = self._get_pairing(a1_copy, a2_copy, cut_p, cut_n, newcell)
if child is None:
continue
# Verify whether the atoms are too close or not:
if atoms_too_close(child, self.blmin, use_tags=self.use_tags):
continue
if self.test_dist_to_slab and len(self.slab) > 0:
if atoms_too_close_two_sets(self.slab, child, self.blmin):
continue
# Passed all the tests
child = self.slab + child
child.set_cell(newcell, scale_atoms=False)
child.wrap()
return child
return None
def mutate(self, atoms):
""" Do the mutation of the atoms input. """
reflect = self.reflect
tc = True
slab = atoms[0:len(atoms) - self.n_top]
top = atoms[len(atoms) - self.n_top: len(atoms)]
num = top.numbers
unique_types = list(set(num))
nu = dict()
for u in unique_types:
nu[u] = sum(num == u)
n_tries = 1000
counter = 0
changed = False
while tc and counter < n_tries:
counter += 1
cand = top.copy()
pos = cand.get_positions()
cm = np.average(top.get_positions(), axis=0)
# first select a randomly oriented cutting plane
theta = pi * random()
phi = 2. * pi * random()
n = (cos(phi) * sin(theta), sin(phi) * sin(theta), cos(theta))
n = np.array(n)
# Calculate all atoms signed distance to the cutting plane
D = []
for (i, p) in enumerate(pos):
d = np.dot(p - cm, n)
D.append((i, d))
# Sort the atoms by their signed distance
D.sort(key=lambda x: x[1])
nu_taken = dict()
# Select half of the atoms needed for a full cluster
p_use = []
n_use = []
for (i, d) in D:
if num[i] not in nu_taken.keys():
nu_taken[num[i]] = 0
if nu_taken[num[i]] < nu[num[i]] / 2.:
p_use.append(pos[i])
n_use.append(num[i])
nu_taken[num[i]] += 1
# calculate the mirrored position and add these.
pn = []
for p in p_use:
pt = p - 2. * np.dot(p - cm, n) * n
if reflect:
pt = -pt + 2 * cm + 2 * n * np.dot(pt - cm, n)
pn.append(pt)
n_use.extend(n_use)
p_use.extend(pn)
# In the case of an uneven number of
# atoms we need to add one extra
for n in nu.keys():
if nu[n] % 2 == 0:
continue
while sum(n_use == n) > nu[n]:
for i in xrange(int(len(n_use) / 2), len(n_use)):
if n_use[i] == n:
del p_use[i]
del n_use[i]
break
assert sum(n_use == n) == nu[n]
# Make sure we have the correct number of atoms
# and rearrange the atoms so they are in the right order
for i in xrange(len(n_use)):
if num[i] == n_use[i]:
continue
for j in xrange(i + 1, len(n_use)):
if n_use[j] == num[i]:
tn = n_use[i]
tp = p_use[i]
n_use[i] = n_use[j]
p_use[i] = p_use[j]
p_use[j] = tp
n_use[j] = tn
# Finally we check that nothing is too close in the end product.
cand = Atoms(num, p_use, cell=slab.get_cell(), pbc=slab.get_pbc())
tc = atoms_too_close(cand, self.blmin)
if tc:
continue
tc = atoms_too_close_two_sets(slab, cand, self.blmin)
if not changed and counter > int(n_tries / 2):
reflect = not reflect
changed = True
tot = slab + cand
if counter == n_tries:
return None
return tot
def cross(self, a1, a2, test_dist_to_slab=True):
"""Crosses the two atoms objects and returns one"""
if len(a1) != len(self.slab) + self.n_top:
raise ValueError('Wrong size of structure to optimize')
if len(a1) != len(a2):
raise ValueError('The two structures do not have the same length')
N = self.n_top
# Only consider the atoms to optimize
a1 = a1[len(a1) - N:len(a1)]
a2 = a2[len(a2) - N:len(a2)]
if not np.array_equal(a1.numbers, a2.numbers):
err = 'Trying to pair two structures with different stoichiometry'
raise ValueError(err)
# Find the common center of the two clusters
c1cm = np.average(a1.get_positions(), axis=0)
c2cm = np.average(a2.get_positions(), axis=0)
cutting_point = (c1cm + c2cm) / 2.
counter = 0
too_close = True
n_max = 1000
# Run until a valid pairing is made or 1000 pairings are tested.
while too_close and counter < n_max:
# Generate the cutting plane
theta = pi * random()
phi = 2. * pi * random()
n = (cos(phi) * sin(theta), sin(phi) * sin(theta), cos(theta))
n = np.array(n)
# Get the pairing
top = self._get_pairing_(a1,
a2,
cutting_plane=n,
cutting_point=cutting_point)
# Check if the candidate is valid
too_close = atoms_too_close(top, self.blmin)
if not too_close and test_dist_to_slab:
too_close = atoms_too_close_two_sets(self.slab, top,
self.blmin)
# Verify that the generated structure contains atoms from
# both parents
n1 = -1 * np.ones((N, ))
n2 = -1 * np.ones((N, ))
for i in xrange(N):
for j in xrange(N):
if np.all(a1.positions[j, :] == top.positions[i, :]):
n1[i] = j
break
elif np.all(a2.positions[j, :] == top.positions[i, :]):
n2[i] = j
break
assert (n1[i] > -1 and n2[i] == -1) or (n1[i] == -1
and n2[i] > -1)
if not (len(n1[n1 > -1]) > 0 and len(n2[n2 > -1]) > 0):
too_close = True
counter += 1
if counter == n_max:
return None
return self.slab + top
a1.info['confid'] = 1
a2 = sg.get_new_candidate()
a2.info['confid'] = 2
# Define and test genetic operators
pairing = CutAndSplicePairing(blmin,
p1=1.,
p2=0.,
minfrac=0.15,
cellbounds=cellbounds,
use_tags=True)
a3, desc = pairing.get_new_individual([a1, a2])
cell = a3.get_cell()
assert cellbounds.is_within_bounds(cell)
assert not atoms_too_close(a3, blmin, use_tags=True)
n_top = len(a1)
strainmut = StrainMutation(blmin,
stddev=0.7,
cellbounds=cellbounds,
use_tags=True)
softmut = SoftMutation(blmin,
bounds=[2., 5.],
used_modes_file=None,
use_tags=True)
rotmut = RotationalMutation(blmin, fraction=0.3, min_angle=0.5 * np.pi)
rattlemut = RattleMutation(blmin,
n_top,
rattle_prop=0.3,
rattle_strength=0.5,
def get_new_candidate(self, maxiter=None):
""" Returns a new candidate.
maxiter: upper bound on the total number of times
the random position generator is called
when generating the new candidate.
By default (maxiter=None) no such bound
is imposed. If the generator takes too
long time to create a new candidate, it
may be suitable to specify a finite value.
When the bound is exceeded, None is returned.
"""
pbc = [True] * 3
blmin = self.blmin
# generating the cell
# cell splitting:
# choose factors according to the probabilities
r = random()
cumprob = 0
for split, prob in self.splits.items():
cumprob += prob
if cumprob > r:
break
directions = sample(range(3), len(split))
repeat = [1, 1, 1]
for i, d in enumerate(directions):
repeat[d] = split[i]
repeat = tuple(repeat)
nparts = np.product(repeat)
target_volume = self.volume / nparts
# Randomly create a cell; without loss of generality,
# a lower triangular form can be used, with tilt factors
# within certain bounds.
# For a cell to be valid, the full cell has to satisfy
# the cellbounds constraints. Additionally, the length of
# each subcell vector has to be greater than the largest
# (X,X)-minimal-interatomic-distance in blmin.
if self.cell is not None:
full_cell = np.copy(self.cell)
cell = (full_cell.T / repeat).T
valid = True
else:
valid = False
while not valid:
blminmax = max([blmin[k] for k in blmin if k[0] == k[1]])
cell = np.zeros((3, 3))
l = target_volume**0.33
cell[0, 0] = random() * l
cell[1, 0] = (random() - 0.5) * cell[0, 0]
cell[1, 1] = random() * l
cell[2, 0] = (random() - 0.5) * cell[0, 0]
cell[2, 1] = (random() - 0.5) * cell[1, 1]
cell[2, 2] = random() * l
volume = abs(np.linalg.det(cell))
cell *= (target_volume / volume)**0.33
full_cell = (repeat * cell.T).T
valid = True
if self.cellbounds is not None:
if not self.cellbounds.is_within_bounds(full_cell):
valid = False
for i in range(3):
if np.linalg.norm(cell[i, :]) < blminmax:
valid = False
# generating the atomic positions
blocks = []
surplus = []
indices = []
for i, (block, count) in enumerate(self.blocks):
count_part = int(np.ceil(count * 1. / nparts))
surplus.append(nparts * count_part - count)
blocks.extend([block] * count_part)
indices.extend([i] * count_part)
N_blocks = len(blocks)
# The ordering is shuffled so different blocks
# are added in random order.
order = list(range(N_blocks))
shuffle(order)
blocks = [blocks[i] for i in order]
indices = np.array(indices)[order]
# Runs until we have found a valid candidate.
cand = Atoms('', cell=cell, pbc=pbc)
niter = 0
for i in range(N_blocks):
atoms = blocks[i].copy()
atoms.set_tags(i)
rotate = len(atoms) > 1
# Make each new position one at a time.
while maxiter is None or niter < maxiter:
cop = atoms.get_positions().mean(axis=0)
pos = random_pos(cell)
atoms.translate(pos - cop)
if rotate:
phi, theta, psi = 360 * np.random.random(3)
atoms.euler_rotate(phi=phi,
theta=0.5 * theta,
psi=psi,
center=pos)
# add if it fits:
attempt = cand + atoms
attempt.wrap()
too_close = atoms_too_close(attempt, blmin, use_tags=True)
if not too_close:
cand += atoms
break
niter += 1
else:
# Reached upper bound on iteration count
cand = None
break
if cand is None:
return None
# rebuild the candidate after repeating,
# randomly deleting surplus blocks and
# sorting back to the original order
tags = cand.get_tags()
nrep = int(np.prod(repeat))
cand_full = cand.repeat(repeat)
tags_full = cand_full.get_tags()
for i in range(nrep):
tags_full[len(cand) * i:len(cand) * (i + 1)] += i * N_blocks
cand_full.set_tags(tags_full)
cand = Atoms('', cell=full_cell, pbc=pbc)
indices_full = np.tile(indices, nrep)
tag_counter = 0
for i, (block, count) in enumerate(self.blocks):
tags = np.where(indices_full == i)[0]
bad = np.random.choice(tags, size=surplus[i], replace=False)
for tag in tags:
if tag not in bad:
select = [a.index for a in cand_full if a.tag == tag]
atoms = cand_full[select] # is indeed a copy!
atoms.set_tags(tag_counter)
assert len(atoms) == len(block)
cand += atoms
tag_counter += 1
return cand
def mutate(self, atoms):
""" Does the actual mutation. """
N = len(atoms) if self.n_top is None else self.n_top
slab = atoms[:len(atoms) - N]
atoms = atoms[-N:]
mutant = atoms.copy()
gather_atoms_by_tag(mutant)
pos = mutant.get_positions()
tags = mutant.get_tags()
eligible_tags = tags if self.tags is None else self.tags
indices = {}
for tag in np.unique(tags):
hits = np.where(tags == tag)[0]
if len(hits) > 1 and tag in eligible_tags:
indices[tag] = hits
n_rot = int(np.ceil(len(indices) * self.fraction))
chosen_tags = np.random.choice(list(indices.keys()),
size=n_rot,
replace=False)
too_close = True
count = 0
maxcount = 10000
while too_close and count < maxcount:
newpos = np.copy(pos)
for tag in chosen_tags:
p = np.copy(newpos[indices[tag]])
cop = np.mean(p, axis=0)
if len(p) == 2:
line = (p[1] - p[0]) / np.linalg.norm(p[1] - p[0])
while True:
axis = np.random.random(3)
axis /= np.linalg.norm(axis)
a = np.arccos(np.dot(axis, line))
if np.pi / 4 < a < np.pi * 3 / 4:
break
else:
axis = np.random.random(3)
axis /= np.linalg.norm(axis)
angle = self.min_angle
angle += 2 * (np.pi - self.min_angle) * np.random.random()
m = get_rotation_matrix(axis, angle)
newpos[indices[tag]] = np.dot(m, (p - cop).T).T + cop
mutant.set_positions(newpos)
mutant.wrap()
too_close = atoms_too_close(mutant, self.blmin, use_tags=True)
count += 1
if not too_close and self.test_dist_to_slab:
too_close = atoms_too_close_two_sets(slab, mutant, self.blmin)
if count == maxcount:
mutant = None
else:
mutant = slab + mutant
return mutant
def cross(self, a1, a2, test_dist_to_slab=True):
"""Crosses the two atoms objects and returns one"""
if len(a1) != len(self.slab) + self.n_top:
raise ValueError('Wrong size of structure to optimize')
if len(a1) != len(a2):
raise ValueError('The two structures do not have the same length')
N = self.n_top
# Only consider the atoms to optimize
a1 = a1[len(a1) - N: len(a1)]
a2 = a2[len(a2) - N: len(a2)]
if not np.array_equal(a1.numbers, a2.numbers):
err = 'Trying to pair two structures with different stoichiometry'
raise ValueError(err)
# Find the common center of the two clusters
c1cm = np.average(a1.get_positions(), axis=0)
c2cm = np.average(a2.get_positions(), axis=0)
cutting_point = (c1cm + c2cm) / 2.
counter = 0
too_close = True
n_max = 1000
# Run until a valid pairing is made or 1000 pairings are tested.
while too_close and counter < n_max:
# Generate the cutting plane
theta = pi * random()
phi = 2. * pi * random()
n = (cos(phi) * sin(theta), sin(phi) * sin(theta), cos(theta))
n = np.array(n)
# Get the pairing
top = self._get_pairing_(a1, a2,
cutting_plane=n,
cutting_point=cutting_point)
# Check if the candidate is valid
too_close = atoms_too_close(top, self.blmin)
if not too_close and test_dist_to_slab:
too_close = atoms_too_close_two_sets(self.slab,
top, self.blmin)
# Verify that the generated structure contains atoms from
# both parents
n1 = -1 * np.ones((N, ))
n2 = -1 * np.ones((N, ))
for i in xrange(N):
for j in xrange(N):
if np.all(a1.positions[j, :] == top.positions[i, :]):
n1[i] = j
break
elif np.all(a2.positions[j, :] == top.positions[i, :]):
n2[i] = j
break
assert (n1[i] > -1 and n2[i] == -1) or (n1[i] == -1 and
n2[i] > -1)
if not (len(n1[n1 > -1]) > 0 and len(n2[n2 > -1]) > 0):
too_close = True
counter += 1
if counter == n_max:
return None
return self.slab + top
def test_chain_operators(seed):
from ase.ga.startgenerator import StartGenerator
from ase.ga.cutandsplicepairing import CutAndSplicePairing
from ase.ga.standardmutations import StrainMutation
from ase.ga.utilities import (closest_distances_generator, atoms_too_close,
CellBounds)
import numpy as np
from ase import Atoms
# set up the random number generator
rng = np.random.RandomState(seed)
slab = Atoms('', cell=(0, 16, 16), pbc=[True, False, False])
blocks = ['C'] * 8
n_top = 8
use_tags = False
num_vcv = 1
box_volume = 8. * n_top
blmin = closest_distances_generator(atom_numbers=[6],
ratio_of_covalent_radii=0.6)
cellbounds = CellBounds(
bounds={
'phi': [0.1 * 180., 0.9 * 180.],
'chi': [0.1 * 180., 0.9 * 180.],
'psi': [0.1 * 180., 0.9 * 180.],
'a': [1, 6]
})
box_to_place_in = [[None, 6., 6.], [None, [0., 4., 0.], [0., 0., 4.]]]
sg = StartGenerator(slab,
blocks,
blmin,
box_volume=box_volume,
splits=None,
box_to_place_in=box_to_place_in,
number_of_variable_cell_vectors=num_vcv,
cellbounds=cellbounds,
test_too_far=True,
test_dist_to_slab=False,
rng=rng)
parents = []
for i in range(2):
a = None
while a is None:
a = sg.get_new_candidate()
a.info['confid'] = i
parents.append(a)
assert len(a) == n_top
assert len(np.unique(a.get_tags())) == 8
assert np.allclose(a.get_pbc(), slab.get_pbc())
p = a.get_positions()
assert np.min(p[:, 1:]) > 6.
assert np.max(p[:, 1:]) < 6. + 4.
assert not atoms_too_close(a, blmin, use_tags=use_tags)
c = a.get_cell()
assert np.allclose(c[1:], slab.get_cell()[1:])
assert cellbounds.is_within_bounds(c)
v = a.get_volume() * (4. / 16.)**2
assert abs(v - box_volume) < 1e-5
# Test cut-and-splice pairing and strain mutation
pairing = CutAndSplicePairing(slab,
n_top,
blmin,
number_of_variable_cell_vectors=num_vcv,
p1=1.,
p2=0.,
minfrac=0.15,
cellbounds=cellbounds,
use_tags=use_tags,
rng=rng)
strainmut = StrainMutation(blmin,
cellbounds=cellbounds,
number_of_variable_cell_vectors=num_vcv,
use_tags=use_tags,
rng=rng)
strainmut.update_scaling_volume(parents)
for operator in [pairing, strainmut]:
child = None
while child is None:
child, desc = operator.get_new_individual(parents)
assert not atoms_too_close(child, blmin, use_tags=use_tags)
cell = child.get_cell()
assert cellbounds.is_within_bounds(cell)
assert np.allclose(cell[1:], slab.get_cell()[1:])
def cross(self, a1, a2):
"""Crosses the two atoms objects and returns one"""
if len(a1) != len(a2):
raise ValueError('The two structures do not have the same length')
N = len(a1) if self.n_top is None else self.n_top
slab = a1[:len(a1) - N]
a1 = a1[-N:]
a2 = a2[-N:]
if not np.array_equal(a1.numbers, a2.numbers):
err = 'Trying to pair two structures with different stoichiometry'
raise ValueError(err)
if self.use_tags and not np.array_equal(a1.get_tags(), a2.get_tags()):
err = 'Trying to pair two structures with different tags'
raise ValueError(err)
a1_copy = a1.copy()
a2_copy = a2.copy()
if self.cellbounds is not None:
if not self.cellbounds.is_within_bounds(a1_copy.get_cell()):
niggli_reduce(a1_copy)
if not self.cellbounds.is_within_bounds(a2_copy.get_cell()):
niggli_reduce(a2_copy)
pos1_ref = a1_copy.get_positions()
pos2_ref = a2_copy.get_positions()
invalid = True
counter = 0
maxcount = 1000
# Run until a valid pairing is made or 1000 pairings are tested.
while invalid and counter < maxcount:
counter += 1
# Choose direction of cutting plane normal (0, 1, or 2):
direction = randrange(3)
# Randomly translate parent structures:
for a, pos in zip([a1_copy, a2_copy], [pos1_ref, pos2_ref]):
a.set_positions(pos)
cell = a.get_cell()
for i in range(3):
r = random()
cond1 = i == direction and r < self.p1
cond2 = i != direction and r < self.p2
if cond1 or cond2:
a.positions += random() * cell[i, :]
if self.use_tags:
gather_atoms_by_tag(a)
else:
a.wrap()
# Perform the pairing:
fraction = random()
child = self._get_pairing(a1_copy,
a2_copy,
direction=direction,
fraction=fraction)
if child is None:
continue
# Verify whether the atoms are too close or not:
invalid = atoms_too_close(child,
self.blmin,
use_tags=self.use_tags)
if invalid:
continue
elif self.test_dist_to_slab:
invalid = atoms_too_close_two_sets(slab, child, self.blmin)
if counter == maxcount:
return None
return child
