org.cpsolver.coursett.constraint

Class MinimizeNumberOfUsedRoomsConstraint

java.lang.Object

org.cpsolver.ifs.model.Constraint<V,T>

org.cpsolver.ifs.assignment.context.ConstraintWithContext<Lecture,Placement,MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext>

org.cpsolver.coursett.constraint.MinimizeNumberOfUsedRoomsConstraint

All Implemented Interfaces:

Comparable<Constraint<Lecture,Placement>>, CanHoldContext, HasAssignmentContext<Lecture,Placement,MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext>, WeakeningConstraint<Lecture,Placement>

public class MinimizeNumberOfUsedRoomsConstraint
extends ConstraintWithContext<Lecture,Placement,MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext>
implements WeakeningConstraint<Lecture,Placement>

Minimize number of used rooms within the set of classes.

This constraint implements the following distribution/group constraint:

MIN_ROOM_USE (Minimize Number Of Rooms Used)
Minimize number of rooms used by the given set of classes.

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/.

Author:

Tomáš Müller

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext

Field Summary

Fields inherited from class org.cpsolver.ifs.model.Constraint

iConstraintListeners, iId

Fields inherited from interface org.cpsolver.ifs.assignment.context.CanHoldContext

sMaxSize

Constructor Summary

Constructors

Constructor and Description
MinimizeNumberOfUsedRoomsConstraint(DataProperties config)

Method Summary

Modifier and Type	Method and Description
void	computeConflicts(Assignment<Lecture,Placement> assignment, Placement placement, Set<Placement> conflicts) The only method which has to be implemented by any constraint.
MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext	createAssignmentContext(Assignment<Lecture,Placement> assignment) Create a new assignment context for the given assignment.
int	estimateLimit()
String	getName() Constraint's name -- for printing purposes
boolean	inConflict(Assignment<Lecture,Placement> assignment, Placement placement) Returns true if the given assignment is inconsistent with the existing assignments respecting this constraint.
String	toString()
void	weaken(Assignment<Lecture,Placement> assignment) Weaken the constraint.
void	weaken(Assignment<Lecture,Placement> assignment, Placement value) Weaken the constraint enough so that it can assign the given value.

Methods inherited from class org.cpsolver.ifs.assignment.context.ConstraintWithContext

assigned, getAssignmentContextReference, getContext, getContext, setAssignmentContextReference, setModel, unassigned

Methods inherited from class org.cpsolver.ifs.model.Constraint

addConstraintListener, addVariable, assignedVariables, compareTo, computeConflictsNoForwardCheck, constraintListeners, countAssignedVariables, countVariables, equals, getDescription, getId, getModel, hashCode, isConsistent, isHard, removeConstraintListener, removeVariable, variables

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MinimizeNumberOfUsedRoomsConstraint

public MinimizeNumberOfUsedRoomsConstraint(DataProperties config)

Method Detail

computeConflicts

public void computeConflicts(Assignment<Lecture,Placement> assignment,
                             Placement placement,
                             Set<Placement> conflicts)

Description copied from class: Constraint

The only method which has to be implemented by any constraint. It returns the values which needs to be unassigned in order to make this constraint consistent with the given value if it is assigned to its variable. The computed list of conflicting values is added to the given set of conflicts.

Specified by:

computeConflicts in class Constraint<Lecture,Placement>

Parameters:

assignment - current assignment

placement - value to be assigned to its variable

conflicts - resultant set of conflicting values

inConflict

public boolean inConflict(Assignment<Lecture,Placement> assignment,
                          Placement placement)

Description copied from class: Constraint

Returns true if the given assignment is inconsistent with the existing assignments respecting this constraint. This method is used by MAC (see MacPropagation).

Overrides:

inConflict in class Constraint<Lecture,Placement>

Parameters:

assignment - current assignment

placement - given value

Returns:

true if there is a conflict with other assigned variables of the constraint

getName

public String getName()

Description copied from class: Constraint

Constraint's name -- for printing purposes

Overrides:

getName in class Constraint<Lecture,Placement>

Returns:

constraint name

estimateLimit

public int estimateLimit()

toString

public String toString()

Overrides:

toString in class Object

weaken

public void weaken(Assignment<Lecture,Placement> assignment)

Description copied from interface: WeakeningConstraint

Weaken the constraint. This method is called if the constraint participates in an unassigned of a variable.

Specified by:

weaken in interface WeakeningConstraint<Lecture,Placement>

Parameters:

assignment - current assignment

weaken

public void weaken(Assignment<Lecture,Placement> assignment,
                   Placement value)

Description copied from interface: WeakeningConstraint

Weaken the constraint enough so that it can assign the given value.

Specified by:

weaken in interface WeakeningConstraint<Lecture,Placement>

Parameters:

assignment - current assignment

value - a conflicting value to be assigned

createAssignmentContext

public MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext createAssignmentContext(Assignment<Lecture,Placement> assignment)

Description copied from interface: HasAssignmentContext

Create a new assignment context for the given assignment. If there are already some variables assigned in the value, the method should make sure that the context is appropriately initialized.

Specified by:

createAssignmentContext in interface HasAssignmentContext<Lecture,Placement,MinimizeNumberOfUsedRoomsConstraint.MinimizeNumberOfUsedRoomsConstraintContext>

Parameters:

assignment - an assignment for which there needs to be an assignment context

Returns:

a new instance of the assignment context, filled according to the given assignment