uf3.forcefield.calculator.UFCalculator¶

class UFCalculator(model: uf3.regression.least_squares.WeightedLinearModel)[source]¶

Bases: ase.calculators.calculator.Calculator

ASE Calculator for energies, forces, and stresses using a fit UF potential. Optionally compute elastic constants and phonon spectra.

Basic calculator implementation.

restart: str: Prefix for restart file. May contain a directory. Default is None: don’t restart.
ignore_bad_restart_file: bool: Deprecated, please do not use. Passing more than one positional argument to Calculator() is deprecated and will stop working in the future. Ignore broken or missing restart file. By default, it is an error if the restart file is missing or broken.
directory: str or PurePath: Working directory in which to read and write files and perform calculations.
label: str: Name used for all files. Not supported by all calculators. May contain a directory, but please use the directory parameter for that instead.
atoms: Atoms object: Optional Atoms object to which the calculator will be attached. When restarting, atoms will get its positions and unit-cell updated from file.

Methods

`band_structure`	Create band-structure object for plotting.
`calculate`	Do the calculation.
`calculate_numerical_forces`	Calculate numerical forces using finite difference.
`calculate_numerical_stress`	Calculate numerical stress using finite difference.
`calculate_properties`	This method is experimental; currently for internal use.
`calculation_required`	Check if a calculation is required.
`check_state`	Check for any system changes since last calculation.
`export_properties`
`get_atoms`
`get_charges`
`get_default_parameters`
`get_dipole_moment`
`get_elastic_constants`	Compute elastic constants.
`get_forces`	Return the forces in a configuration.
`get_magnetic_moment`
`get_magnetic_moments`	Calculate magnetic moments projected onto atoms.
`get_phonon_data`	Compute phonon spectra using Phonopy.
`get_potential_energies`
`get_potential_energy`	Evaluate the total energy of a configuration.
`get_property`	Get the named property.
`get_stress`	Return the (numerical) stress.
`get_stresses`	the calculator should return intensive stresses, i.e., such that stresses.sum(axis=0) == stress
`read`	Read atoms, parameters and calculated properties from output file.
`read_atoms`
`relax_fmax`	Minimize maximum force using ASE's QuasiNewton optimizer.
`reset`	Clear all information from old calculation.
`set`	Set parameters like set(key1=value1, key2=value2, ...).
`set_label`	Set label and convert label to directory and prefix.
`todict`

Attributes

`chemical_system`
`coefficients`
`default_parameters`	Default parameters
`degree`
`directory`
`discard_results_on_any_change`	Whether we purge the results following any change in the set() method.
`element_list`
`ignored_changes`	Properties of Atoms which we ignore for the purposes of cache
`implemented_properties`	Properties calculator can handle (energy, forces, ...)
`interactions_map`
`knot_subintervals`
`label`
`partition_sizes`
`r_cut`
`r_max_map`
`r_min_map`

band_structure()¶: Create band-structure object for plotting.

calculate(atoms=None, properties=['energy'], system_changes=['positions', 'numbers', 'cell', 'pbc', 'initial_charges', 'initial_magmoms'])¶

Do the calculation.

properties: list of str: List of what needs to be calculated. Can be any combination of ‘energy’, ‘forces’, ‘stress’, ‘dipole’, ‘charges’, ‘magmom’ and ‘magmoms’.
system_changes: list of str: List of what has changed since last calculation. Can be any combination of these six: ‘positions’, ‘numbers’, ‘cell’, ‘pbc’, ‘initial_charges’ and ‘initial_magmoms’.

Subclasses need to implement this, but can ignore properties and system_changes if they want. Calculated properties should be inserted into results dictionary like shown in this dummy example:

self.results = {'energy': 0.0,
                'forces': np.zeros((len(atoms), 3)),
                'stress': np.zeros(6),
                'dipole': np.zeros(3),
                'charges': np.zeros(len(atoms)),
                'magmom': 0.0,
                'magmoms': np.zeros(len(atoms))}

The subclass implementation should first call this implementation to set the atoms attribute and create any missing directories.

calculate_numerical_forces(atoms, d=0.001)¶

Calculate numerical forces using finite difference.

All atoms will be displaced by +d and -d in all directions.

calculate_numerical_stress(atoms, d=1e-06, voigt=True)¶: Calculate numerical stress using finite difference.

calculate_properties(atoms, properties)¶: This method is experimental; currently for internal use.

calculation_required(atoms: ase.atoms.Atoms, quantities: List) → bool[source]¶: Check if a calculation is required.

check_state(atoms, tol=1e-15)¶: Check for any system changes since last calculation.

get_elastic_constants(atoms: ase.atoms.Atoms, n: int = 5, d: float = 1.0) → List[source]¶

Compute elastic constants.

Parameters

atoms (ase.Atoms) – configuration of interest.
n (int) – number of distortions to sample for fitting.
d (float) – maximum displacement in percent.

Returns

elastic constants.

Return type

results (list)

get_forces(atoms: Optional[ase.atoms.Atoms] = None) → numpy.ndarray[source]¶: Return the forces in a configuration.

get_magnetic_moments(atoms=None)¶: Calculate magnetic moments projected onto atoms.

get_phonon_data(atoms: ase.atoms.Atoms, n_super: int = 5, disp: float = 0.05) → Tuple[Any, Dict, Dict][source]¶

Compute phonon spectra using Phonopy.

Parameters

atoms (ase.Atoms) – configuration of interest.
n_super (int) – size of supercell, i.e. # images in each direction.
disp (float) – magnitude of displacement in percent.

get_potential_energy(atoms: Optional[ase.atoms.Atoms] = None, force_consistent: Optional[bool] = None) → float[source]¶: Evaluate the total energy of a configuration.

get_property(name, atoms=None, allow_calculation=True)¶: Get the named property.

get_stress(atoms: Optional[ase.atoms.Atoms] = None, **kwargs) → numpy.ndarray[source]¶: Return the (numerical) stress.

get_stresses(atoms=None)¶: the calculator should return intensive stresses, i.e., such that stresses.sum(axis=0) == stress

read(label)¶

Read atoms, parameters and calculated properties from output file.

Read result from self.label file. Raise ReadError if the file is not there. If the file is corrupted or contains an error message from the calculation, a ReadError should also be raised. In case of succes, these attributes must set:

atoms: Atoms object: The state of the atoms from last calculation.
parameters: Parameters object: The parameter dictionary.
results: dict: Calculated properties like energy and forces.

The FileIOCalculator.read() method will typically read atoms and parameters and get the results dict by calling the read_results() method.

relax_fmax(geom: ase.atoms.Atoms, fmax: float = 0.05, relax_cell: bool = True, verbose: bool = False, timeout: float = 60.0, **kwargs) → ase.atoms.Atoms[source]¶: Minimize maximum force using ASE’s QuasiNewton optimizer.

reset()¶: Clear all information from old calculation.

set(**kwargs)¶

Set parameters like set(key1=value1, key2=value2, …).

A dictionary containing the parameters that have been changed is returned.

Subclasses must implement a set() method that will look at the chaneged parameters and decide if a call to reset() is needed. If the changed parameters are harmless, like a change in verbosity, then there is no need to call reset().

The special keyword ‘parameters’ can be used to read parameters from a file.

set_label(label)¶

Set label and convert label to directory and prefix.

Examples:

label=’abc’: (directory=’.’, prefix=’abc’)
label=’dir1/abc’: (directory=’dir1’, prefix=’abc’)
label=None: (directory=’.’, prefix=None)