net.sf.cpsolver.exam.heuristics
Class ExamHillClimbing

java.lang.Object
  net.sf.cpsolver.exam.heuristics.ExamHillClimbing

All Implemented Interfaces:

NeighbourSelection, SolutionListener

public class ExamHillClimbing
extends Object
implements NeighbourSelection, SolutionListener

Hill climber. In each iteration, one of the following three neighbourhoods is selected first

• random move (ExamRandomMove)
• period swap (ExamTimeMove)
• room swap (ExamRoomMove)

, then a neighbour is generated and it is accepted if its value ExamSimpleNeighbour.value() is below or equal to zero. The search is stopped after a given amount of idle iterations ( can be defined by problem property HillClimber.MaxIdle).

Version:

ExamTT 1.1 (Examination Timetabling)
Copyright (C) 2008 Tomáš Müller
muller@unitime.org
Lazenska 391, 76314 Zlin, Czech Republic

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 2.1 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Constructor Summary

ExamHillClimbing(DataProperties properties)
Constructor

ExamHillClimbing(DataProperties properties, String name)
Constructor

Method Summary

void	bestCleared(Solution solution) Called by the solution when method Solution.clearBest() is called.
void	bestRestored(Solution solution) Called by the solution when method Solution.restoreBest() is called.
void	bestSaved(Solution solution) Memorize the iteration when the last best solution was found.
void	getInfo(Solution solution, Dictionary info) Called by the solution when it is asked to produce info table, see Solution.getInfo().
void	getInfo(Solution solution, Dictionary info, Vector variables) Called by the solution when it is asked to produce info table, see Solution.getInfo().
void	init(Solver solver) Initialization
Neighbour	selectNeighbour(Solution solution) Select one of the given neighbourhoods randomly, select neighbour, return it if its value is below or equal to zero (continue with the next selection otherwise).
void	solutionUpdated(Solution solution) Called by the solution when it is updated, see Solution.update(double).

Methods inherited from class java.lang.Object

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

Constructor Detail

ExamHillClimbing

public ExamHillClimbing(DataProperties properties)

Constructor

Parameters:

properties - problem properties (use HillClimber.MaxIdle to set maximum number of idle iterations)

ExamHillClimbing

public ExamHillClimbing(DataProperties properties,
                        String name)

Constructor

Parameters:

properties - problem properties (use HillClimber.MaxIdle to set maximum number of idle iterations)

Method Detail

init

public void init(Solver solver)

Initialization

Specified by:

init in interface NeighbourSelection

selectNeighbour

public Neighbour selectNeighbour(Solution solution)

Select one of the given neighbourhoods randomly, select neighbour, return it if its value is below or equal to zero (continue with the next selection otherwise). Return null when the given number of idle iterations is reached.

Specified by:

selectNeighbour in interface NeighbourSelection

Parameters:

solution - given solution

Returns:

a neighbour assignment

bestSaved

public void bestSaved(Solution solution)

Memorize the iteration when the last best solution was found.

Specified by:

bestSaved in interface SolutionListener

Parameters:

solution - source solution

solutionUpdated

public void solutionUpdated(Solution solution)

Description copied from interface: SolutionListener

Called by the solution when it is updated, see Solution.update(double).

Specified by:

solutionUpdated in interface SolutionListener

Parameters:

solution - source solution

getInfo

public void getInfo(Solution solution,
                    Dictionary info)

Description copied from interface: SolutionListener

Called by the solution when it is asked to produce info table, see Solution.getInfo(). A listener can also add some its info into this table.

Specified by:

getInfo in interface SolutionListener

Parameters:

solution - source solution

info - produced info table

getInfo

public void getInfo(Solution solution,
                    Dictionary info,
                    Vector variables)

Description copied from interface: SolutionListener

Called by the solution when it is asked to produce info table, see Solution.getInfo(). A listener can also add some its info into this table.

Specified by:

getInfo in interface SolutionListener

Parameters:

solution - source solution

info - produced info table

variables - only variables from this set are included

bestCleared

public void bestCleared(Solution solution)

Description copied from interface: SolutionListener

Called by the solution when method Solution.clearBest() is called.

Specified by:

bestCleared in interface SolutionListener

Parameters:

solution - source solution

bestRestored

public void bestRestored(Solution solution)

Description copied from interface: SolutionListener

Called by the solution when method Solution.restoreBest() is called.

Specified by:

bestRestored in interface SolutionListener

Parameters:

solution - source solution