org.cpsolver.studentsct.constraint

Class DependentCourses

java.lang.Object

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

org.cpsolver.ifs.model.GlobalConstraint<Request,Enrollment>

org.cpsolver.studentsct.constraint.DependentCourses

All Implemented Interfaces:

Comparable<Constraint<Request,Enrollment>>

public class DependentCourses
extends GlobalConstraint<Request,Enrollment>

Global constraint for dependent courses. If a student requests both a course and its parent (identified by Course.getParent()), the student cannot get the dependent course without also having the parent course assigned.

Version:

StudentSct 1.4 (Student Sectioning)
Copyright (C) 2007 - 2025 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 inherited from class org.cpsolver.ifs.model.Constraint

iConstraintListeners, iId

Constructor Summary

Constructors

Constructor and Description
DependentCourses()

Method Summary

Modifier and Type	Method and Description
boolean	canLeaveUnassigned(Student student, LinkedSections.EnrollmentAssignment assignment, Request parentRequest) A special check for the branch-and-bound routine (such as BranchBoundSelection) which constructs a full schedule for a student.
void	computeConflicts(Assignment<Request,Enrollment> assignment, Enrollment value, Set<Enrollment> conflicts) The only method which has to be implemented by any constraint.
boolean	inConflict(Assignment<Request,Enrollment> assignment, Enrollment value) Conflict check.
boolean	isPartialScheduleInConflict(Student student, LinkedSections.EnrollmentAssignment assignment, int index) A special check for the branch-and-bound routine (such as BranchBoundSelection) which constructs a full schedule for a student.

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

addVariable, assigned, assignedVariables, countAssignedVariables, getName, removeVariable, toString, unassigned, variables

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

addConstraintListener, compareTo, computeConflictsNoForwardCheck, constraintListeners, countVariables, equals, getDescription, getId, getModel, hashCode, isConsistent, isHard, removeConstraintListener, setModel

Methods inherited from class java.lang.Object

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

Constructor Detail

DependentCourses

public DependentCourses()

Method Detail

computeConflicts

public void computeConflicts(Assignment<Request,Enrollment> assignment,
                             Enrollment value,
                             Set<Enrollment> 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<Request,Enrollment>

Parameters:

assignment - current assignment

value - value to be assigned to its variable

conflicts - resultant set of conflicting values

inConflict

public boolean inConflict(Assignment<Request,Enrollment> assignment,
                          Enrollment value)

Conflict check. There is a conflict when a student has an assigned course that has a parent course, the student also has the parent course requested, but does not have the parent course assigned.

Overrides:

inConflict in class Constraint<Request,Enrollment>

Parameters:

assignment - current assignment

value - given value

Returns:

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

isPartialScheduleInConflict

public boolean isPartialScheduleInConflict(Student student,
                                           LinkedSections.EnrollmentAssignment assignment,
                                           int index)

A special check for the branch-and-bound routine (such as BranchBoundSelection) which constructs a full schedule for a student. There is a conflict when there is a dependent course assigned within the already constructed schedule (up to the given index) and the already constructed schedule also contains the parent course but it is not assigned.

Parameters:

student - a student

assignment - current assigned up to the given index

index - index of the variable that is being assigned

Returns:

true if there is no conflict

canLeaveUnassigned

public boolean canLeaveUnassigned(Student student,
                                  LinkedSections.EnrollmentAssignment assignment,
                                  Request parentRequest)

A special check for the branch-and-bound routine (such as BranchBoundSelection) which constructs a full schedule for a student. The parent request cannot be left unassigned if it contains a parent course for any of the already assigned dependent course.

Parameters:

student - a student

assignment - current assigned up to the given index

parentRequest - parent request (that is being checked if it can be left unassigned)

Returns:

true if the parent request can be left unassigned (it is not a parent course for an assigned dependent course)