org.cpsolver.coursett.heuristics

Class PlacementSelection

java.lang.Object

org.cpsolver.coursett.heuristics.PlacementSelection

All Implemented Interfaces:

ValueSelection<Lecture,Placement>

public class PlacementSelection
extends Object
implements ValueSelection<Lecture,Placement>

Placement (value) selection.

We have implemented a hierarchical handling of the value selection criteria (see HeuristicSelector).

The value selection heuristics also allow for random selection of a value with a given probability (random walk, e.g., 2%) and, in the case of MPP, to select the initial value (if it exists) with a given probability (e.g., 70%).

Parameters (general):

Related Solver Parameters

Parameter	Type	Comment
Placement.RandomWalkProb	Double	Random walk probability
Placement.GoodSelectionProb	Double	Good value (not removed from domain) selection probability (MAC related)
Placement.TabuLength	Integer	Tabu-list length (-1 means do not use tabu-list)
Placement.MPP_InitialProb	Double	MPP initial selection probability
Placement.MPP_Limit	Integer	MPP: limit on the number of perturbations (-1 for no limit)
Placement.MPP_PenaltyLimit	Double	MPP: limit on the perturbations penalty (-1 for no limit)

Parameters (for each level of selection):

Related Solver Parameters

Parameter	Type	Comment
Placement.NrAssignmentsWeight1 Placement.NrAssignmentsWeight2 Placement.NrAssignmentsWeight3	Double	Number of previous assignments of the value weight
Placement.NrConflictsWeight1,2,3	Double	Number of conflicts weight
Placement.WeightedConflictsWeight1,2,3	Double	Weighted conflicts weight (Conflict-based Statistics related)
Placement.NrPotentialConflictsWeight1,2,3	Double	Number of potential conflicts weight (Conflict-based Statistics related)
Placement.MPP_DeltaInitialAssignmentWeight1,2,3	Double	Delta initial assigments weight (MPP, violated initials related)
Placement.NrHardStudConfsWeight1,2,3	Double	Hard student conflicts weight (student conflicts between single-section classes)
Placement.NrStudConfsWeight1,2,3	Double	Student conflicts weight
Placement.TimePreferenceWeight1,2,3	Double	Time preference weight
Placement.DeltaTimePreferenceWeight1,2,3	Double	Time preference delta weight (difference between before and after assignemnt of the value)
Placement.ConstrPreferenceWeight1,2,3	Double	Constraint preference weight
Placement.RoomPreferenceWeight1,2,3	Double	Room preference weight
Placement.UselessSlotsWeight1,2,3	Double	Useless slot weight
Placement.TooBigRoomWeight1,2,3	Double	Too big room weight
Placement.DistanceInstructorPreferenceWeight1,2,3	Double	Distance (of the rooms of the back-to-back classes) based instructor preferences weight
Placement.DeptSpreadPenaltyWeight1,2,3	Double	Department spreading: penalty of when a slot over initial allowance is used
Placement.ThresholdKoef1,2	Double	Threshold koeficient of the level

Version:

CourseTT 1.3 (University Course Timetabling)
Copyright (C) 2006 - 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/.

See Also:

PlacementSelection

Field Summary

Fields

Modifier and Type	Field and Description
static String	GOOD_SELECTION_PROB
static String	INITIAL_SELECTION_PROB
static String	NR_MPP_LIMIT
static String	NR_MPP_PENALTY_LIMIT
static String	NR_THRESHOLD_KOEF
static String	RW_SELECTION_PROB
static String	TABU_LENGTH

Constructor Summary

Constructors

Constructor and Description
PlacementSelection(DataProperties properties)

Method Summary

Modifier and Type	Method and Description
boolean	containsItselfSingletonOrCommited(TimetableModel model, Set<Placement> values, Placement selectedValue)
void	init(Solver<Lecture,Placement> solver) Initialization
Placement	selectValue(Solution<Lecture,Placement> solution, Lecture var) Value selection

Methods inherited from class java.lang.Object

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

Field Detail

GOOD_SELECTION_PROB

public static final String GOOD_SELECTION_PROB

See Also:

Constant Field Values

RW_SELECTION_PROB

public static final String RW_SELECTION_PROB

See Also:

Constant Field Values

INITIAL_SELECTION_PROB

public static final String INITIAL_SELECTION_PROB

See Also:

Constant Field Values

NR_MPP_LIMIT

public static final String NR_MPP_LIMIT

See Also:

Constant Field Values

NR_MPP_PENALTY_LIMIT

public static final String NR_MPP_PENALTY_LIMIT

See Also:

Constant Field Values

NR_THRESHOLD_KOEF

public static final String NR_THRESHOLD_KOEF

See Also:

Constant Field Values

TABU_LENGTH

public static final String TABU_LENGTH

See Also:

Constant Field Values

Constructor Detail

PlacementSelection

public PlacementSelection(DataProperties properties)

Method Detail

init

public void init(Solver<Lecture,Placement> solver)

Description copied from interface: ValueSelection

Initialization

Specified by:

init in interface ValueSelection<Lecture,Placement>

Parameters:

solver - current solver

selectValue

public Placement selectValue(Solution<Lecture,Placement> solution,
                             Lecture var)

Description copied from interface: ValueSelection

Value selection

Specified by:

selectValue in interface ValueSelection<Lecture,Placement>

Parameters:

solution - current solution

var - selected variable

Returns:

selected value (of the given variable)

containsItselfSingletonOrCommited

public boolean containsItselfSingletonOrCommited(TimetableModel model,
                                                 Set<Placement> values,
                                                 Placement selectedValue)