net.sf.cpsolver.ifs.algorithms

Class StepCountingHillClimber<V extends Variable<V,T>,T extends Value<V,T>>

java.lang.Object

net.sf.cpsolver.ifs.algorithms.NeighbourSearch<V,T>

net.sf.cpsolver.ifs.algorithms.HillClimber<V,T>

net.sf.cpsolver.ifs.algorithms.StepCountingHillClimber<V,T>

All Implemented Interfaces:

NeighbourSelection<V,T>, LazyNeighbour.LazyNeighbourAcceptanceCriterion<V,T>, SolutionListener<V,T>

public class StepCountingHillClimber<V extends Variable<V,T>,T extends Value<V,T>>
extends HillClimber<V,T>

Step counting hill climber. Unlike with the ordinary hill climber, there is a bound. The bound is updated (to the value of the current solution) after a given number of moves. Based on the given mode, either all moves, only accepted moves, or only improving moves are counted.

Version:

IFS 1.2 (Iterative Forward Search)
Copyright (C) 2014 Tomáš Müller
muller@unitime.org
http://muller.unitime.org

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not see http://www.gnu.org/licenses/.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StepCountingHillClimber.Mode

Field Summary

Fields

Modifier and Type	Field and Description
protected Double	iBound
protected int	iCounter
protected int	iCounterLimit
protected StepCountingHillClimber.Mode	iCounterMode

Fields inherited from class net.sf.cpsolver.ifs.algorithms.HillClimber

iBestValue, iLastImprovingIter, iMaxIdleIters, iSetHCMode

Fields inherited from class net.sf.cpsolver.ifs.algorithms.NeighbourSearch

iDF2, iIter, iLog, iPhase, iProgress, iT0

Constructor Summary

Constructors

Constructor and Description
StepCountingHillClimber(DataProperties properties, String name) Constructor HillClimber.CounterLimit ... number of moves after which the bound is reset (defaults to 1000) HillClimber.CounterMode ... counter mode (all: count all moves, accepted: count accepted moves, improving: count improving moves)

Method Summary

Modifier and Type	Method and Description
protected boolean	accept(Model<V,T> model, Neighbour<V,T> neighbour, double value, boolean lazy) Accept any move that does not worsen the solution (value <= 0) or that is below the bound.
void	activate(Solution<V,T> solution) Reset the bound and the steps counter.
protected boolean	canContinue(Solution<V,T> solution) Stop the search when the number of idle iterations is reached and the bound is no longer decreasing
void	incIteration(Solution<V,T> solution) Increase iteration number, also update bound when the given number of steps is reached.

Methods inherited from class net.sf.cpsolver.ifs.algorithms.HillClimber

bestSaved, getParameterBaseName, init, setPhase

Methods inherited from class net.sf.cpsolver.ifs.algorithms.NeighbourSearch

accept, accept, addNeighbourSelection, bestCleared, bestRestored, deactivate, generateMove, getInfo, getInfo, getNeighbours, getTimeMillis, logNeibourStatus, nextNeighbourSelection, selectNeighbour, setHCMode, solutionUpdated

Methods inherited from class java.lang.Object

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

Field Detail

iBound

protected Double iBound

iCounter

protected int iCounter

iCounterLimit

protected int iCounterLimit

iCounterMode

protected StepCountingHillClimber.Mode iCounterMode

Constructor Detail

StepCountingHillClimber

public StepCountingHillClimber(DataProperties properties,
                               String name)

Constructor

• HillClimber.CounterLimit ... number of moves after which the bound is reset (defaults to 1000)
• HillClimber.CounterMode ... counter mode (all: count all moves, accepted: count accepted moves, improving: count improving moves)

Method Detail

activate

public void activate(Solution<V,T> solution)

Reset the bound and the steps counter.

Overrides:

activate in class HillClimber<V extends Variable<V,T>,T extends Value<V,T>>

incIteration

public void incIteration(Solution<V,T> solution)

Increase iteration number, also update bound when the given number of steps is reached.

Overrides:

incIteration in class HillClimber<V extends Variable<V,T>,T extends Value<V,T>>

accept

protected boolean accept(Model<V,T> model,
                         Neighbour<V,T> neighbour,
                         double value,
                         boolean lazy)

Accept any move that does not worsen the solution (value <= 0) or that is below the bound. Also increase the step counter.

Overrides:

accept in class HillClimber<V extends Variable<V,T>,T extends Value<V,T>>

canContinue

protected boolean canContinue(Solution<V,T> solution)

Stop the search when the number of idle iterations is reached and the bound is no longer decreasing

Overrides:

canContinue in class HillClimber<V extends Variable<V,T>,T extends Value<V,T>>