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reverse_mutation.py
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reverse_mutation.py
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from pymoo.model.mutation import Mutation
import numpy as np
from pymoo.operators.crossover.order_crossover import random_sequence
def inversion_mutation(y, seq, inplace=True):
y = y if inplace else np.copy(y)
seq = seq if not None else random_sequence(len(y))
start, end = seq
y[start:end + 1]["mining"] = np.flip(y[start:end + 1]["mining"])
return y
class CustomInversionMutation(Mutation):
def __init__(self, prob=1.0):
"""
This mutation is applied to permutations. It randomly selects a segment of a chromosome and reverse its order.
For instance, for the permutation `[1, 2, 3, 4, 5]` the segment can be `[2, 3, 4]` which results in `[1, 4, 3, 2, 5]`.
Parameters
----------
prob : float
Probability to apply the mutation to the individual
"""
super().__init__()
self.prob = prob
def _do(self, problem, X, **kwargs):
Y = X.copy()
for i, y in enumerate(X):
if np.random.random() < self.prob:
seq = random_sequence(len(y))
Y[i] = inversion_mutation(y, seq, inplace=True)
return Y