net.sf.cpsolver.coursett.constraint
Class JenrlConstraint

java.lang.Object
  net.sf.cpsolver.ifs.model.Constraint
      net.sf.cpsolver.ifs.model.BinaryConstraint
          net.sf.cpsolver.coursett.constraint.JenrlConstraint

public class JenrlConstraint
extends BinaryConstraint

Join student enrollment constraint.
This constraint is placed between all pairs of classes where there is at least one student attending both classes. It represents a number of student conflicts (number of joined enrollments), if the given two classes overlap in time.
Also, it dynamically maintains the counter of all student conflicts. It is a soft constraint.

Version:

CourseTT 1.1 (University Course Timetabling)
Copyright (C) 2006 Tomáš Müller
muller@unitime.org
Lazenska 391, 76314 Zlin, Czech Republic

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 2.1 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Field Summary

Fields inherited from class net.sf.cpsolver.ifs.model.Constraint

iAssignedVariables, iConstraintListeners, iId

Constructor Summary

JenrlConstraint()
Constructor

Method Summary

boolean	areStudentConflictsDistance()
boolean	areStudentConflictsDistance(Value value)
boolean	areStudentConflictsHard()
void	assigned(long iteration, Value value) Given value is to be assigned to its varable.
void	computeConflicts(Value value, Set conflicts) The only method which has to be implemented by any constraint.
void	decJenrl(Student student) Decrement the number of joined enrollments (during student final sectioning)
long	getJenrl() Number of joined enrollments (during student final sectioning)
double	getJenrlWeight(Student student)
int	getNrStudents()
void	incJenrl(Student student) Increment the number of joined enrollments (during student final sectioning)
boolean	inConflict(Value value) Returns true if the given assignment is inconsistent with the existing assignments respecting this constraint.
boolean	isConsistent(Value value1, Value value2) Returns true if the given assignments are consistent respecting this constraint.
boolean	isHard() Returns true if the constraint is hard.
boolean	isInConflict() True if the given two lectures overlap in time
static boolean	isInConflict(Placement p1, Placement p2) Returns true if the given placements are overlapping or they are back-to-back and too far for students.
static boolean	isInConflict(Placement p1, Placement p2, boolean useDistances)
boolean	isInConflictPrecise() True if the given two lectures overlap in time
boolean	isOfTheSameProblem()
long	jenrl(Variable variable, Value value) Number of joined enrollments if the given value is assigned to the given variable
String	toString()
void	unassigned(long iteration, Value value) Given value is unassigned from its varable.

Methods inherited from class net.sf.cpsolver.ifs.model.BinaryConstraint

addVariable, another, first, isFirst, second

Methods inherited from class net.sf.cpsolver.ifs.model.Constraint

addConstraintListener, assignedVariables, constraintListeners, countAssignedVariables, countVariables, equals, getDescription, getId, getModel, getName, hashCode, removeConstraintListener, removeVariable, setModel, variables

Methods inherited from class java.lang.Object

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

Constructor Detail

JenrlConstraint

public JenrlConstraint()

Constructor

Method Detail

computeConflicts

public void computeConflicts(Value value,
                             Set 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

Parameters:

value - value to be assigned to its varaible

conflicts - resultant set of conflicting values

inConflict

public boolean inConflict(Value value)

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

isConsistent

public boolean isConsistent(Value value1,
                            Value value2)

Description copied from class: Constraint

Returns true if the given assignments are consistent respecting this constraint. This method is used by MAC (see MacPropagation).

Overrides:

isConsistent in class Constraint

unassigned

public void unassigned(long iteration,
                       Value value)

Description copied from class: Constraint

Given value is unassigned from its varable.

Overrides:

unassigned in class Constraint

isInConflict

public static boolean isInConflict(Placement p1,
                                   Placement p2)

Returns true if the given placements are overlapping or they are back-to-back and too far for students.

isInConflict

public static boolean isInConflict(Placement p1,
                                   Placement p2,
                                   boolean useDistances)

assigned

public void assigned(long iteration,
                     Value value)

Description copied from class: Constraint

Given value is to be assigned to its varable. In this method, the constraint should unassigns all varaibles which are in conflict with the given assignment because of this constraint.

Overrides:

assigned in class Constraint

jenrl

public long jenrl(Variable variable,
                  Value value)

Number of joined enrollments if the given value is assigned to the given variable

isInConflict

public boolean isInConflict()

True if the given two lectures overlap in time

isInConflictPrecise

public boolean isInConflictPrecise()

True if the given two lectures overlap in time

incJenrl

public void incJenrl(Student student)

Increment the number of joined enrollments (during student final sectioning)

getJenrlWeight

public double getJenrlWeight(Student student)

decJenrl

public void decJenrl(Student student)

Decrement the number of joined enrollments (during student final sectioning)

getJenrl

public long getJenrl()

Number of joined enrollments (during student final sectioning)

getNrStudents

public int getNrStudents()

isHard

public boolean isHard()

Description copied from class: Constraint

Returns true if the constraint is hard. Only hard constraints are allowed to unassign a variable when there is a conflict with a value that is being assigned

Overrides:

isHard in class Constraint

toString

public String toString()

Overrides:

toString in class Object

areStudentConflictsHard

public boolean areStudentConflictsHard()

areStudentConflictsDistance

public boolean areStudentConflictsDistance()

areStudentConflictsDistance

public boolean areStudentConflictsDistance(Value value)

isOfTheSameProblem

public boolean isOfTheSameProblem()