Source code for mchammer.calculators.constituent_strain_calculator

from import ConstituentStrain
from icet import ClusterExpansion
from mchammer.calculators import ClusterExpansionCalculator
from typing import List, Union
import numpy as np

[docs]class ConstituentStrainCalculator(ClusterExpansionCalculator): """ Calculator for handling cluster expansions with strain. Parameters ---------- constituent_strain ConstituentStrain object defining the strain energy properties of the system; the supercell used to create this object should corresponding to the one used when running Monte Carlo simulations with this calculator cluster_expansion cluster expansion from which to build ClusterExpansionCalculator name human-readable identifier for this calculator scaling scaling factor applied to the property value predicted by the cluster expansion """ def __init__(self, constituent_strain: ConstituentStrain, cluster_expansion: ClusterExpansion, name: str = 'Constituent Strain Calculator', scaling: Union[float, int] = None): self.constituent_strain = constituent_strain super().__init__(structure=constituent_strain.supercell, cluster_expansion=cluster_expansion, name=name, scaling=scaling)
[docs] def calculate_total(self, *, occupations: np.ndarray) -> float: """ Calculates and returns the total property value of the current configuration. Parameters ---------- occupations the entire occupation vector (i.e. an array of atomic numbers as integers) """ e = super().calculate_total(occupations=occupations) e += len(occupations) * \ self.constituent_strain.get_constituent_strain(occupations) return e
[docs] def calculate_change(self, *, sites: List[int], current_occupations: List[int], new_site_occupations: List[int]) -> float: """ Calculates and returns the sum of the contributions to the property due to the sites specified in `local_indices` Parameters ---------- sites index of sites at which occupations will be changed current_occupations entire occupation vector (atomic numbers) before change new_site_occupations atomic numbers after change at the sites defined by `sites` """ if len(new_site_occupations) > 1: raise NotImplementedError('Only single flips are currently allowed in ' 'conjunction with the constituent strain calculator.') e = super().calculate_change(sites=sites, current_occupations=current_occupations, new_site_occupations=new_site_occupations) de_cs = self.constituent_strain.get_constituent_strain_change(current_occupations, sites[0]) e += len(current_occupations) * de_cs return e
[docs] def accept_change(self): """ Informs the ConstituentStrain object that the most recent change was accepted, such that the new structure factor can be stored. """ self.constituent_strain.accept_change()