org.cpsolver.studentsct.heuristics.selection

Class StandardSelection

java.lang.Object

org.cpsolver.studentsct.heuristics.selection.StandardSelection

All Implemented Interfaces:

NeighbourSelection<Request,Enrollment>, AssignmentCheck<Request,Enrollment>

Direct Known Subclasses:

CriticalStandardSelection

public class StandardSelection
extends Object
implements NeighbourSelection<Request,Enrollment>, AssignmentCheck<Request,Enrollment>

Use the provided variable and value selection for some time. The provided variable and value selection is used for the number of iterations equal to the number of all variables in the problem. If a complete solution is found, the neighbour selection is stopped (it returns null).

Parameters:

Related Solver Parameters

Parameter	Type	Comment
Neighbour.StandardIterations	Long	Number of iterations to perform. If -1, number of iterations is set to the number of unassigned variables.

Version:

StudentSct 1.3 (Student Sectioning)
Copyright (C) 2007 - 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

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	iCanConflict
protected boolean	iCanHigherPriorityConflict
protected boolean	iCanWorsen
protected boolean	iCanWorsenCritical
protected long	iConflictTimeOut
protected long	iNrIterations
protected boolean	iPreferPriorityStudents
protected long	iTimeOut
protected ValueSelection<Request,Enrollment>	iValueSelection
protected VariableSelection<Request,Enrollment>	iVariableSelection
protected long	iWorsenTimeOut

Constructor Summary

Constructors

Constructor and Description
StandardSelection(DataProperties properties, VariableSelection<Request,Enrollment> variableSelection, ValueSelection<Request,Enrollment> valueSelection) Constructor (variable and value selection are expected to be already initialized).

Method Summary

Modifier and Type	Method and Description
boolean	accept(SimpleNeighbour<Request,Enrollment> n, Solution<Request,Enrollment> solution) Check whether the given neighbors can be returned
boolean	canUnassign(Enrollment enrollment, Enrollment conflict, Assignment<Request,Enrollment> assignment) Check if the given conflicting enrollment can be unassigned
void	init(Solver<Request,Enrollment> solver) Initialization
protected void	init(Solver<Request,Enrollment> solver, String name)
Neighbour<Request,Enrollment>	selectNeighbour(Solution<Request,Enrollment> solution) Employ the provided VariableSelection and ValueSelection and return the selected value as SimpleNeighbour.

Methods inherited from class java.lang.Object

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

Field Detail

iValueSelection

protected ValueSelection<Request,Enrollment> iValueSelection

iVariableSelection

protected VariableSelection<Request,Enrollment> iVariableSelection

iNrIterations

protected long iNrIterations

iPreferPriorityStudents

protected boolean iPreferPriorityStudents

iConflictTimeOut

protected long iConflictTimeOut

iWorsenTimeOut

protected long iWorsenTimeOut

iTimeOut

protected long iTimeOut

iCanConflict

protected boolean iCanConflict

iCanWorsen

protected boolean iCanWorsen

iCanWorsenCritical

protected boolean iCanWorsenCritical

iCanHigherPriorityConflict

protected boolean iCanHigherPriorityConflict

Constructor Detail

StandardSelection

public StandardSelection(DataProperties properties,
                         VariableSelection<Request,Enrollment> variableSelection,
                         ValueSelection<Request,Enrollment> valueSelection)

Constructor (variable and value selection are expected to be already initialized).

Parameters:

properties - configuration

variableSelection - variable selection

valueSelection - value selection

Method Detail

init

public void init(Solver<Request,Enrollment> solver)

Initialization

Specified by:

init in interface NeighbourSelection<Request,Enrollment>

Parameters:

solver - current solver

init

protected void init(Solver<Request,Enrollment> solver,
                    String name)

canUnassign

public boolean canUnassign(Enrollment enrollment,
                           Enrollment conflict,
                           Assignment<Request,Enrollment> assignment)

Check if the given conflicting enrollment can be unassigned

Specified by:

canUnassign in interface AssignmentCheck<Request,Enrollment>

Parameters:

conflict - given enrollment

enrollment - value to be assigned

assignment - current assignment

Returns:

if running MPP, do not unassign initial enrollments

accept

public boolean accept(SimpleNeighbour<Request,Enrollment> n,
                      Solution<Request,Enrollment> solution)

Check whether the given neighbors can be returned

Returns:

by default, any neighbors is accepted

selectNeighbour

public Neighbour<Request,Enrollment> selectNeighbour(Solution<Request,Enrollment> solution)

Employ the provided VariableSelection and ValueSelection and return the selected value as SimpleNeighbour. The selection is stopped (null is returned) after the number of iterations equal to the number of variables in the problem or when a complete solution is found.

Specified by:

selectNeighbour in interface NeighbourSelection<Request,Enrollment>

Parameters:

solution - given solution

Returns:

a neighbour assignment