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import numpy as np
import pytest
from ase.units import GPa
from ase.build import bulk
from ase.calculators.test import gradient_test
from ase.constraints import UnitCellFilter, ExpCellFilter
from ase.optimize import LBFGS, MDMin
from ase.io import Trajectory
@pytest.fixture
def atoms(asap3):
rng = np.random.RandomState(0)
atoms = bulk('Cu', cubic=True)
atoms.positions[:, 0] *= 0.995
atoms.cell += rng.uniform(-1e-2, 1e-2, size=9).reshape((3,3))
atoms.calc = asap3.EMT()
return atoms
@pytest.mark.parametrize('cellfilter', [UnitCellFilter, ExpCellFilter])
def test_pressure(atoms, cellfilter):
xcellfilter = cellfilter(atoms, scalar_pressure=10.0 * GPa)
# test all derivatives
f, fn = gradient_test(xcellfilter)
assert abs(f - fn).max() < 5e-6
opt = LBFGS(xcellfilter)
opt.run(1e-3)
# check pressure is within 0.1 GPa of target
sigma = atoms.get_stress() / GPa
pressure = -(sigma[0] + sigma[1] + sigma[2]) / 3.0
assert abs(pressure - 10.0) < 0.1
@pytest.mark.parametrize('cellfilter', [UnitCellFilter, ExpCellFilter])
def test_cellfilter(atoms, cellfilter):
xcellfilter = cellfilter(atoms)
f, fn = gradient_test(xcellfilter)
assert abs(f - fn).max() < 3e-6
# XXX This test should have some assertions! --askhl
def test_unitcellfilter(asap3):
cu = bulk('Cu') * (6, 6, 6)
cu.calc = asap3.EMT()
f = UnitCellFilter(cu, [1, 1, 1, 0, 0, 0])
opt = LBFGS(f)
with Trajectory('Cu-fcc.traj', 'w', cu) as t:
opt.attach(t)
opt.run(5.0)
# No assertions??
def test_unitcellfilter_hcp(asap3):
cu = bulk('Cu', 'hcp', a=3.6 / 2.0**0.5)
cu.cell[1,0] -= 0.05
cu *= (6, 6, 3)
cu.calc = asap3.EMT()
print(cu.get_forces())
print(cu.get_stress())
f = UnitCellFilter(cu)
opt = MDMin(f, dt=0.01)
with Trajectory('Cu-hcp.traj', 'w', cu) as t:
opt.attach(t)
opt.run(0.2)
# No assertions??
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