Source code for clease.montecarlo.constraints.fixed_indices

from typing import Sequence
from clease.datastructures import SystemChanges
from .mc_constraint import MCConstraint

[docs]class FixedIndices(MCConstraint): """Constrain a given set of indices during an MC run. Any suggested system changes by the MC algorithm are rejected if they invovle an index in the fixed indices. Parameters: fixed_indices: sequence of integers The indices of the atoms object which are to be fixed. """ name = "FixedIndices" def __init__(self, fixed_indices: Sequence[int]): super().__init__() # We use a set for O(1) lookup time # Also, every entry is an index, and should therefore be an int. # Avoid floating point conversion issues with round self.fixed_basis = set(round(idx) for idx in fixed_indices) def __call__(self, system_changes: SystemChanges) -> bool: """Check if any of the proposed changes are from the fixed basis""" return all(change.index not in self.fixed_basis for change in system_changes)