Stopping criteria

The pyvrp.stop module contains the various stopping criteria the pyvrp package ships with. These can be used to stop the GeneticAlgorithm’s’ search whenever some criterion is met: for example, when some maximum number of iterations or run-time is exceeded.

All stopping criteria implement the StoppingCriterion protocol.

class StoppingCriterion(*args, **kwargs)

Protocol that stopping criteria must implement.

Methods

__call__(best_cost)

When called, this stopping criterion should return True if the algorithm should stop, and False otherwise.

class MaxIterations(max_iterations: int)

Criterion that stops after a maximum number of iterations.

Methods

__call__(best_cost)

Call self as a function.

class MaxRuntime(max_runtime: float)

Criterion that stops after a specified maximum runtime.

Methods

__call__(best_cost)

Call self as a function.

class NoImprovement(max_iterations: int)

Criterion that stops if the best solution has not been improved for a fixed number of iterations.

Parameters:

max_iterations

The maximum number of non-improving iterations.

Methods

__call__(best_cost)

Call self as a function.

class TimedNoImprovement(max_iterations: int, max_runtime: float)

Stopping criterion that stops after a given number of iterations without improvement, or after a fixed runtime (whichever happens first).

Methods

__call__(best_cost)

Call self as a function.