Disable crossover in NSGA3

[faranak1991]

Hello,

I want to disable the crossover in the NSGA3 algorithm and only use my custom Mutation operator, after choosing crossover=None in the algorithm:

algorithm = NSGA2(
pop_size=population,
sampling=random_population,
crossover=None,
mutation=CustomMutation(),
n_offsprings=population,
verbose=True,
eliminate_duplicates=True )

It shows this error :
in _do
n_matings = math.ceil(n_offsprings / self.crossover.n_offsprings)
AttributeError: 'NoneType' object has no attribute 'n_offsprings'

Any help to address this issue will be appreciated ?

[blankjul]

You can use NoCrossover() to just copy individuals from the population without any change.