Source code for stk.ea.selection.selectors.worst

"""
Worst
=====

"""

import itertools as it

from stk.molecular import Inchi

from .selector import Selector


[docs]class Worst(Selector): """ Selects batches of molecules, lowest fitness value first. Examples -------- *Yielding Batches Holding Multiple Molecules* Select the worst 5 batches of size 3 .. testcode:: yielding-batches-holding-multiple-molecules import stk worst = stk.Worst(num_batches=5, batch_size=3) population = tuple( stk.MoleculeRecord( topology_graph=stk.polymer.Linear( building_blocks=( stk.BuildingBlock( smiles='BrCCBr', functional_groups=[stk.BromoFactory()], ), ), repeating_unit='A', num_repeating_units=2, ), ).with_fitness_value(i) for i in range(10) ) for batch in worst.select(population): # Do stuff with batch. pass """
[docs] def __init__( self, num_batches=None, batch_size=1, duplicate_molecules=True, duplicate_batches=True, key_maker=Inchi(), fitness_modifier=None, ): """ Initialize a :class:`.Worst` instance. Parameters ---------- num_batches : :class:`int`, optional The number of batches to yield. If ``None`` then yielding will continue forever or until the generator is exhausted, whichever comes first. batch_size : :class:`int`, optional The number of molecules yielded at once. duplicate_molecules : :class:`bool`, optional If ``True`` the same molecule can be yielded in more than one batch. duplicate_batches : :class:`bool`, optional If ``True`` the same batch can be yielded more than once. Duplicate batches can occur if the same molecule is found multiple times in a population. key_maker : :class:`.MoleculeKeyMaker`, optional Used to get the keys of molecules, which are used to determine if two molecules are duplicates of each other. fitness_modifier : :class:`callable`, optional Takes the `population` on which :meth:`.select` is called and returns a :class:`dict`, which maps records in the `population` to the fitness values the :class:`.Selector` should use. If ``None``, the regular fitness values of the records are used. """ if fitness_modifier is None: fitness_modifier = self._get_fitness_values self._duplicate_molecules = duplicate_molecules self._duplicate_batches = duplicate_batches self._num_batches = num_batches self._batch_size = batch_size super().__init__( key_maker=key_maker, fitness_modifier=fitness_modifier, )
def _select_from_batches(self, batches, yielded_batches): batches = sorted(batches) if not self._duplicate_molecules: batches = filter( yielded_batches.has_no_yielded_molecules, batches, ) if not self._duplicate_batches: batches = filter( yielded_batches.is_unyielded_batch, batches, ) yield from it.islice(batches, self._num_batches)