propulate.propagators.nm

Module Contents

Classes

ParallelNelderMead

Initialize a Nelder-Mead propagator.
class propulate.propagators.nm.ParallelNelderMead(limits: Dict[str, Tuple[float, float]], rng: random.Random, start: numpy.ndarray, alpha: float = 1.0, gamma: float = 2.0, rho: float = 0.5, sigma: float = 0.5, scale: float = 1.0)

Bases: propulate.propagators.base.Propagator

Initialize a Nelder-Mead propagator.

Parameters:

  • limits (Dict[str, Tuple[float, float]] | Dict[str, Tuple[int, int]] | Dict[str, Tuple[str, ...]]) – The search space, i.e., the limits of the (hyper-)parameters to be optimized.

  • rng (random.Random, optional) – The separate random number generator of the Propulate optimization.

  • start (numpy.ndarray) – The starting point around which the first simplex is constructed.

  • alpha (float, optional) – The reflection parameter.

  • gamma (float, optional) – The expansion parameter.

  • rho (float, optional) – The contraction parameter.

  • sigma (float, optional) – The shrinking parameter.

  • scale (float, optional) – The size of the initial simplex.

__call__(inds: List[propulate.population.Individual]) → propulate.population.Individual

Apply the Nelder-Mead propagator.

Parameters:

inds (List[propulate.population.Individual]) – The individuals the propagator is applied to.

Returns:

The individual after application of the propagator.

Return type:

propulate.population.Individual

compute_centroid() → numpy.ndarray

Compute the centroid of the current simplex.

Returns:

The centroid of current simplex.

Return type:

numpy.ndarray

reflect() → propulate.population.Individual

Nelder-Mead reflect step.

Returns:

The reflection of the worst point in the simplex on the centroid.

Return type:

propulate.population.Individual

expand() → propulate.population.Individual

Nelder-Mead expand step.

Returns:

The reflection of the worst point in the simplex on the centroid with a larger step size.

Return type:

propulate.population.Individual

outercontract() → propulate.population.Individual

Nelder-Mead contract step on the outside of the simplex.

Returns:

The individual contracted on the outside of the simplex.

Return type:

propulate.population.Individual

innercontract() → propulate.population.Individual

Nelder-Mead contract step on the inside of the simplex.

Returns:

The individual contracted on the inside of the simplex.

Return type:

propulate.population.Individual

shrink() → propulate.population.Individual

Nelder-Mead shrink step only touching a single random vertex of the current simplex.

Returns:

The shrunk individual.

Return type:

propulate.population.Individual