ExVrp.PerturbationManager (ExVrp v0.4.2)

Manages perturbation during local search.

In each iteration, it applies a random number of perturbations that strengthen or weaken randomly selected neighbourhoods by inserting or removing clients.

Example

pm = ExVrp.PerturbationManager.new(min: 1, max: 25)
assert pm.min_perturbations == 1
assert pm.max_perturbations == 25

# Initially set to min_perturbations
assert ExVrp.PerturbationManager.num_perturbations(pm) == 1

# Shuffle to pick a new random number
rng = ExVrp.RNG.new(42)
pm = ExVrp.PerturbationManager.shuffle(pm, rng)
num = ExVrp.PerturbationManager.num_perturbations(pm)
assert num >= 1 and num <= 25

Summary

Types

t()

Functions

new(opts \\ [])

Creates a new PerturbationManager.

num_perturbations(perturbation_manager)

Returns the current number of perturbations to apply.

shuffle(pm, rng)

Shuffles to pick a new random number of perturbations.

Types

t()

@type t() :: %ExVrp.PerturbationManager{
  max_perturbations: non_neg_integer(),
  min_perturbations: non_neg_integer(),
  ref: reference()
}

Functions

new(opts \\ [])

@spec new(keyword()) :: t()

Creates a new PerturbationManager.

Options

:min - Minimum number of perturbations (default: 1)
:max - Maximum number of perturbations (default: 25)

Examples

iex> pm = ExVrp.PerturbationManager.new()
iex> pm.min_perturbations
1
iex> pm.max_perturbations
25

iex> pm = ExVrp.PerturbationManager.new(min: 5, max: 10)
iex> pm.min_perturbations
5

num_perturbations(perturbation_manager)

@spec num_perturbations(t()) :: non_neg_integer()

Returns the current number of perturbations to apply.

Initially this is set to min_perturbations. Call shuffle/2 to pick a new random value within the [min, max] range.

shuffle(pm, rng)

@spec shuffle(t(), reference()) :: t()

Shuffles to pick a new random number of perturbations.

The new value is drawn uniformly from [min_perturbations, max_perturbations].

Example

pm = ExVrp.PerturbationManager.new(min: 1, max: 10)
rng = ExVrp.RNG.new(42)
pm = ExVrp.PerturbationManager.shuffle(pm, rng)
num = ExVrp.PerturbationManager.num_perturbations(pm)
assert num >= 1 and num <= 10