org.cpsolver.ifs.algorithms.neighbourhoods

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

java.lang.Object

org.cpsolver.ifs.algorithms.neighbourhoods.RandomSwapMove<V,T>

org.cpsolver.ifs.algorithms.neighbourhoods.SuggestionMove<V,T>

Type Parameters:

V - Variable

T - Value

All Implemented Interfaces:

HillClimberSelection, NeighbourSelection<V,T>

public class SuggestionMove<V extends Variable<V,T>,T extends Value<V,T>>
extends RandomSwapMove<V,T>

Suggestion move. A variable is selected randomly. A limited depth backtracking is used to find a possible change (much like the suggestions in UniTime when the interactive solver is used). Unlike in NeighbourSelectionWithSuggestions, the very first found suggestion is returned. The depth is limited by SuggestionMove.Depth parameter (defaults to 3). Also, instead of using a time limit, the width of the search is limited by the number of values that are tried for each variable (parameter SuggestionMove.MaxAttempts, defaults to 10). When used in HillClimber, the first suggestion that does not worsen the solution is returned.

Version:

IFS 1.3 (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/.

Author:

Tomáš Müller

Nested Class Summary

Nested classes/interfaces inherited from class org.cpsolver.ifs.algorithms.neighbourhoods.RandomSwapMove

RandomSwapMove.SwapNeighbour

Field Summary

Fields

Modifier and Type	Field and Description
protected int	iSuggestionDepth
protected int	iTimeLimit

Fields inherited from class org.cpsolver.ifs.algorithms.neighbourhoods.RandomSwapMove

iHC, iMaxAttempts

Constructor Summary

Constructors

Constructor and Description
SuggestionMove(DataProperties config)

Method Summary

Modifier and Type	Method and Description
void	init(Solver<V,T> solver) Criterion initialization
Neighbour<V,T>	selectNeighbour(Solution<V,T> solution) select a neighbour of a given solution

Methods inherited from class org.cpsolver.ifs.algorithms.neighbourhoods.RandomSwapMove

isTimeLimitReached, resolve, setHcMode

Methods inherited from class java.lang.Object

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

Field Detail

iSuggestionDepth

protected int iSuggestionDepth

iTimeLimit

protected int iTimeLimit

Constructor Detail

SuggestionMove

public SuggestionMove(DataProperties config)
               throws Exception

Throws:

Exception

Method Detail

init

public void init(Solver<V,T> solver)

Description copied from interface: NeighbourSelection

Criterion initialization

Specified by:

init in interface NeighbourSelection<V extends Variable<V,T>,T extends Value<V,T>>

Overrides:

init in class RandomSwapMove<V extends Variable<V,T>,T extends Value<V,T>>

Parameters:

solver - current solver

selectNeighbour

public Neighbour<V,T> selectNeighbour(Solution<V,T> solution)

Description copied from interface: NeighbourSelection

select a neighbour of a given solution

Specified by:

selectNeighbour in interface NeighbourSelection<V extends Variable<V,T>,T extends Value<V,T>>

Overrides:

selectNeighbour in class RandomSwapMove<V extends Variable<V,T>,T extends Value<V,T>>

Parameters:

solution - given solution

Returns:

a neighbour assignment