optuna.samplers.nsgaii.UNDXCrossover
- class optuna.samplers.nsgaii.UNDXCrossover(sigma_xi=0.5, sigma_eta=None)[source]
Unimodal Normal Distribution Crossover used by
NSGAIISampler
.Generates child individuals from the three parents using a multivariate normal distribution.
- Parameters
Note
Added in v3.0.0 as an experimental feature. The interface may change in newer versions without prior notice. See https://github.com/optuna/optuna/releases/tag/v3.0.0.
Methods
crossover
(parents_params, rng, study, ...)Perform crossover of selected parent individuals.
Attributes
n_parents
- crossover(parents_params, rng, study, search_space_bounds)[source]
Perform crossover of selected parent individuals.
This method is called in
sample_relative()
.- Parameters
parents_params (ndarray) – A
numpy.ndarray
with dimensionsnum_parents x num_parameters
. Represents a parameter space for each parent individual. This space is continuous for numerical parameters.rng (RandomState) – An instance of
numpy.random.RandomState
.study (Study) – Target study object.
search_space_bounds (ndarray) – A
numpy.ndarray
with dimensionslen_search_space x 2
representing numerical distribution bounds constructed from transformed search space.
- Returns
A 1-dimensional
numpy.ndarray
containing new parameter combination.- Return type
ndarray