def read(self, method='standard', direction='central'):
"""Read data from a pre-performed calculation."""
self.timer.start('read')
self.timer.start('vibrations')
Vibrations.read(self, method, direction)
# we now have:
# self.H : Hessian matrix
# self.im : 1./sqrt(masses)
# self.modes : Eigenmodes of the mass weighted Hessian
self.om_Q = self.hnu.real # energies in eV
self.om_v = self.om_Q
# pre-factors for one vibrational excitation
with np.errstate(divide='ignore'):
self.vib01_Q = np.where(self.om_Q > 0,
1. / np.sqrt(2 * self.om_Q), 0)
# -> sqrt(amu) * Angstrom
self.vib01_Q *= np.sqrt(u.Ha * u._me / u._amu) * u.Bohr
self.timer.stop('vibrations')
self.timer.start('excitations')
self.init_parallel_read()
if not hasattr(self, 'ex0E_p'):
if self.overlap:
self.read_excitations_overlap()
else:
self.read_excitations()
self.timer.stop('excitations')
self.timer.stop('read')
def test_harmonic_vibrations(self, testdir):
"""Check the numerics with a trivial case: one atom in harmonic well"""
rng = np.random.RandomState(42)
k = rng.rand()
ref_atoms = Atoms('H', positions=np.zeros([1, 3]))
atoms = ref_atoms.copy()
mass = atoms.get_masses()[0]
atoms.calc = ForceConstantCalculator(D=np.eye(3) * k,
ref=ref_atoms,
f0=np.zeros((1, 3)))
vib = Vibrations(atoms, name='harmonic')
vib.run()
vib.read()
expected_energy = (
units._hbar # In J/s
* np.sqrt(k # In eV/A^2
* units._e # eV -> J
* units.m**2 # A^-2 -> m^-2
/ mass # in amu
/ units._amu # amu^-1 -> kg^-1
)) / units._e # J/s -> eV/s
assert np.allclose(vib.get_energies(), expected_energy)
def read(self, method='standard', direction='central'):
"""Read data from a pre-performed calculation."""
if not hasattr(self, 'modes'):
self.timer.start('read vibrations')
Vibrations.read(self, method, direction)
# we now have:
# self.H : Hessian matrix
# self.im : 1./sqrt(masses)
# self.modes : Eigenmodes of the mass weighted H
self.om_r = self.hnu.real # energies in eV
self.timer.stop('read vibrations')
if not hasattr(self, 'ex0E_p'):
self.read_excitations()
def read(self, method='standard', direction='central'):
"""Read data from a pre-performed calculation."""
if not hasattr(self, 'modes'):
self.timer.start('read vibrations')
Vibrations.read(self, method, direction)
# we now have:
# self.H : Hessian matrix
# self.im : 1./sqrt(masses)
# self.modes : Eigenmodes of the mass weighted H
self.om_r = self.hnu.real # energies in eV
self.timer.stop('read vibrations')
if not hasattr(self, 'ex0E_p'):
self.read_excitations()
def test_pickle_manipulation(self, n2_emt):
atoms = n2_emt
vib = Vibrations(atoms, name='interrupt')
vib.run()
disp_file = 'interrupt.1x-.pckl'
comb_file = 'interrupt.all.pckl'
assert os.path.isfile(disp_file)
assert not os.path.isfile(comb_file)
with pytest.raises(RuntimeError):
vib.split()
# Build a combined file
assert vib.combine() == 13
# Individual displacements should be gone, combination should exist
assert not os.path.isfile(disp_file)
assert os.path.isfile(comb_file)
# Not allowed to run after data has been combined
with pytest.raises(RuntimeError):
vib.run()
# But reading is allowed
vib.read()
# Splitting should fail if any split file already exists
with open(disp_file, 'w') as f:
f.write("hello")
with pytest.raises(RuntimeError):
vib.split()
os.remove(disp_file)
# Now split() for real: replace .all.pckl file with displacements
vib.split()
assert os.path.isfile(disp_file)
assert not os.path.isfile(comb_file)
# Not allowed to clobber existing combined file
with open(comb_file, 'w') as f:
f.write("Hello")
with pytest.raises(RuntimeError):
vib.combine()
os.remove(comb_file)
# Combining data also fails if some data is missing
os.remove('interrupt.1x-.pckl')
with pytest.raises(RuntimeError):
vib.combine()
vib.clean()
def test_json_manipulation(self, testdir, random_dimer):
vib = Vibrations(random_dimer, name='interrupt')
vib.run()
disp_file = Path('interrupt/cache.1x-.json')
comb_file = Path('interrupt/combined.json')
assert disp_file.is_file()
assert not comb_file.is_file()
# Should do nothing harmful as files are already split
# (It used to raise an error but this is no longer implemented.)
vib.split()
# Build a combined file
assert vib.combine() == 13
# Individual displacements should be gone, combination should exist
assert not disp_file.is_file()
assert comb_file.is_file()
# Not allowed to run after data has been combined
with pytest.raises(RuntimeError):
vib.run()
# But reading is allowed
vib.read()
# Splitting should fail if any split file already exists
with open(disp_file, 'w') as fd:
fd.write("hello")
with pytest.raises(AssertionError):
vib.split()
os.remove(disp_file)
# Now split() for real: replace .all.json file with displacements
vib.split()
assert disp_file.is_file()
assert not comb_file.is_file()
def test_vibration_on_surface(self, testdir):
from ase.build import fcc111, add_adsorbate
ag_slab = fcc111('Ag', (4, 4, 2), a=2)
n2 = Atoms('N2',
positions=[[0., 0., 0.], [0., np.sqrt(2),
np.sqrt(2)]])
add_adsorbate(ag_slab, n2, height=1, position='fcc')
# Add an interaction between the N atoms
hessian_bottom_corner = np.zeros((2, 3, 2, 3))
hessian_bottom_corner[-1, :, -2] = [1, 1, 1]
hessian_bottom_corner[-2, :, -1] = [1, 1, 1]
hessian = np.zeros((34, 3, 34, 3))
hessian[32:, :, 32:, :] = hessian_bottom_corner
ag_slab.calc = ForceConstantCalculator(hessian.reshape(
(34 * 3, 34 * 3)),
ref=ag_slab.copy(),
f0=np.zeros((34, 3)))
# Check that Vibrations with restricted indices returns correct Hessian
vibs = Vibrations(ag_slab, indices=[-2, -1])
vibs.run()
vibs.read()
assert_array_almost_equal(vibs.get_vibrations().get_hessian(),
hessian_bottom_corner)
# These should blow up if the vectors don't match number of atoms
vibs.summary()
vibs.write_jmol()
for i in range(6):
# Frozen atoms should have zero displacement
assert_array_almost_equal(vibs.get_mode(i)[0], [0., 0., 0.])
# The N atoms should have finite displacement
assert np.all(vibs.get_mode(i)[-2:, :])
def vibrate(self, atoms: Atoms, indices: list, read_only=False):
'''
This method uses ase.vibrations module, see more for info.
User provides the FHI-aims parameters, the Atoms object and list
of indices of atoms to be vibrated. Variables related to FHI-aims are governed by the React object.
Calculation folders are generated automatically and a sockets calculator is used for efficiency.
Work in progress
Args:
atoms: Atoms object
indices: list
List of indices of atoms that require vibrations
read_only: bool
Flag for postprocessing - if True, the method only extracts information from existing files,
no calculations are performed
Returns:
Zero-Point Energy: float
'''
'''Retrieve common properties'''
basis_set = self.basis_set
hpc = self.hpc
params = self.params
parent_dir = os.getcwd()
dimensions = sum(atoms.pbc)
if not self.filename:
'''develop a naming scheme based on chemical formula'''
self.filename = atoms.get_chemical_formula()
vib_dir = parent_dir + "/VibData_" + self.filename + "/Vibs"
print(vib_dir)
vib = Vibrations(atoms, indices=indices, name=vib_dir)
'''If a calculation was terminated prematurely (e.g. time limit) empty .json files remain and the calculation
of the corresponding stretch modes would be skipped on restart. The line below prevents this'''
vib.clean(empty_files=True)
'''Extract vibration data from existing files'''
if read_only:
vib.read()
else:
'''Calculate required vibration modes'''
required_cache = [
os.path.join(vib_dir, "cache." + str(x) + y + ".json")
for x in indices
for y in ["x+", "x-", "y+", "y-", "y-", "z+", "z-"]
]
check_required_modes_files = np.array(
[os.path.exists(file) for file in required_cache])
if np.all(check_required_modes_files == True):
vib.read()
else:
'''Set the environment variables for geometry optimisation'''
set_aims_command(hpc=hpc,
basis_set=basis_set,
defaults=2020,
nodes_per_instance=self.nodes_per_instance)
'''Generate a unique folder for aims calculation'''
counter, subdirectory_name = self._restart_setup(
"Vib",
filename=self.filename,
restart=False,
verbose=False)
os.makedirs(subdirectory_name, exist_ok=True)
os.chdir(subdirectory_name)
'''Name the aims output file'''
out = str(counter) + "_" + str(self.filename) + ".out"
'''Calculate vibrations and write the in a separate directory'''
with _calc_generator(params, out_fn=out,
dimensions=dimensions)[0] as calculator:
if not self.dry_run:
atoms.calc = calculator
else:
atoms.calc = EMT()
vib = Vibrations(atoms, indices=indices, name=vib_dir)
vib.run()
vib.summary()
'''Generate a unique folder for aims calculation'''
if not read_only:
os.chdir(vib_dir)
vib.write_mode()
os.chdir(parent_dir)
return vib.get_zero_point_energy()
