com.graphhopper.jsprit.core.algorithm.termination

Class VariationCoefficientTermination

java.lang.Object

com.graphhopper.jsprit.core.algorithm.termination.VariationCoefficientTermination

All Implemented Interfaces:

AlgorithmStartsListener, IterationEndsListener, IterationStartsListener, VehicleRoutingAlgorithmListener, PrematureAlgorithmTermination

public class VariationCoefficientTermination
extends Object
implements PrematureAlgorithmTermination, IterationStartsListener, AlgorithmStartsListener, IterationEndsListener

Terminates algorithm prematurely based on variationCoefficient (http://en.wikipedia.org/wiki/Coefficient_of_variation).

Note, that this must be registered as AlgorithmListener
It will be activated by:

algorithm.setPrematureAlgorithmTermination(this);
algorithm.addListener(this);

Author:

stefan schroeder

Constructor Summary

Constructors

Constructor and Description
VariationCoefficientTermination(int noIterations, double variationCoefficientThreshold) Constructs termination.

Method Summary

Modifier and Type	Method and Description
void	informAlgorithmStarts(VehicleRoutingProblem problem, VehicleRoutingAlgorithm algorithm, Collection<VehicleRoutingProblemSolution> solutions)
void	informIterationEnds(int i, VehicleRoutingProblem problem, Collection<VehicleRoutingProblemSolution> solutions)
void	informIterationStarts(int i, VehicleRoutingProblem problem, Collection<VehicleRoutingProblemSolution> solutions)
boolean	isPrematureBreak(SearchStrategy.DiscoveredSolution discoveredSolution) Returns true if algorithm should terminate, false otherwise.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

VariationCoefficientTermination

public VariationCoefficientTermination(int noIterations,
                                       double variationCoefficientThreshold)

Constructs termination.

Parameters:

noIterations - size of the sample, i.e. number previous solutions values to take into account. If for example noIterations = 10 then every 10th iteration the variationCoefficient will be calculated with the last 10 solution values.

variationCoefficientThreshold - the threshold used to terminate the algorithm. If the calculated variationCoefficient is smaller than the specified threshold, the algorithm terminates.

Method Detail

toString

public String toString()

Overrides:

toString in class Object

isPrematureBreak

public boolean isPrematureBreak(SearchStrategy.DiscoveredSolution discoveredSolution)

Description copied from interface: PrematureAlgorithmTermination

Returns true if algorithm should terminate, false otherwise.

Specified by:

isPrematureBreak in interface PrematureAlgorithmTermination

Parameters:

discoveredSolution - the discovered solution

Returns:

true if algorithm should terminate, false otherwise

informAlgorithmStarts

public void informAlgorithmStarts(VehicleRoutingProblem problem,
                                  VehicleRoutingAlgorithm algorithm,
                                  Collection<VehicleRoutingProblemSolution> solutions)

Specified by:

informAlgorithmStarts in interface AlgorithmStartsListener

informIterationEnds

public void informIterationEnds(int i,
                                VehicleRoutingProblem problem,
                                Collection<VehicleRoutingProblemSolution> solutions)

Specified by:

informIterationEnds in interface IterationEndsListener

informIterationStarts

public void informIterationStarts(int i,
                                  VehicleRoutingProblem problem,
                                  Collection<VehicleRoutingProblemSolution> solutions)

Specified by:

informIterationStarts in interface IterationStartsListener