from pygenalgo.genome.chromosome import Chromosome
from pygenalgo.operators.mutation.mutate_operator import MutationOperator
[docs]
class FlipMutator(MutationOperator):
"""
Description:
Flip mutator, mutates the chromosome by selecting randomly
a position and flip its Gene value (0 -> 1, or 1 -> 0).
"""
def __init__(self, mutate_probability: float = 0.1) -> None:
"""
Construct a 'FlipMutator' object with a given probability value.
:param mutate_probability: (float).
"""
# Call the super constructor with the provided
# probability value.
super().__init__(mutate_probability)
# _end_def_
[docs]
def mutate(self, individual: Chromosome) -> None:
"""
Perform the mutation operation by randomly flipping a gene.
:param individual: (Chromosome).
:return: None.
"""
# If the mutation probability is higher than
# a uniformly random value, make the changes.
if self.is_operator_applicable():
# Get the size of the chromosome.
n_genes: int = len(individual)
# Select randomly the mutation point and
# flip the old gene value.
individual[self.rng.integers(n_genes,
dtype=int)].flip()
# Set the fitness to NaN.
individual.invalidate_fitness()
# Increase the mutator counter.
self.inc_counter()
# _end_def_
# _end_class_