net.sf.cpsolver.exam.heuristics
Class ExamConstruction

java.lang.Object
  extended by net.sf.cpsolver.exam.heuristics.ExamConstruction
All Implemented Interfaces:
NeighbourSelection<Exam,ExamPlacement>

public class ExamConstruction
extends Object
implements NeighbourSelection<Exam,ExamPlacement>

Initial solution construction heuristics.

While there are exams that are still not assigned:



If problem property ExamConstruction.CheckLocalOptimality is true, local (time) optimality is enforced at the end of this phase. During this procedure, for each exam, it tries to change the period of the exam so that the time cost is lower (see ExamPlacement.getTimeCost()), but no hard constraint is violated. The problem is considered locally optimal if there is no such move.

Version:
ExamTT 1.2 (Examination Timetabling)
Copyright (C) 2008 - 2010 Tomas Muller
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/.

Constructor Summary
ExamConstruction(DataProperties properties)
          Constructor
 
Method Summary
 Neighbour<Exam,ExamPlacement> checkLocalOptimality(ExamModel model)
          Find a new assignment of one of the assigned exams that improves the time cost ExamPlacement.getTimeCost() and for which there is a set of available rooms Exam.findBestAvailableRooms(ExamPeriodPlacement).
 void init(Solver<Exam,ExamPlacement> solver)
          Initialization
 Neighbour<Exam,ExamPlacement> selectNeighbour(Solution<Exam,ExamPlacement> solution)
          Select a neighbour.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExamConstruction

public ExamConstruction(DataProperties properties)
Constructor

Parameters:
properties - problem properties
Method Detail

init

public void init(Solver<Exam,ExamPlacement> solver)
Initialization

Specified by:
init in interface NeighbourSelection<Exam,ExamPlacement>

checkLocalOptimality

public Neighbour<Exam,ExamPlacement> checkLocalOptimality(ExamModel model)
Find a new assignment of one of the assigned exams that improves the time cost ExamPlacement.getTimeCost() and for which there is a set of available rooms Exam.findBestAvailableRooms(ExamPeriodPlacement). Return null, if there is no such assignment (the problem is considered locally optimal).


selectNeighbour

public Neighbour<Exam,ExamPlacement> selectNeighbour(Solution<Exam,ExamPlacement> solution)
Select a neighbour. While there are exams that are still not assigned: Return null when done (all variables are assigned and the problem is locally optimal).

Specified by:
selectNeighbour in interface NeighbourSelection<Exam,ExamPlacement>
Parameters:
solution - given solution
Returns:
a neighbour assignment


Copyright © 2014 UniTime LLC. All Rights Reserved.