org.cpsolver.coursett.constraint

Class MaxHalfDaysFlexibleConstraint

java.lang.Object

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

org.cpsolver.ifs.assignment.context.ConstraintWithContext<Lecture,Placement,FlexibleConstraint.FlexibleConstraintContext>

org.cpsolver.coursett.constraint.FlexibleConstraint

org.cpsolver.coursett.constraint.MaxHalfDaysFlexibleConstraint

All Implemented Interfaces:

Comparable<Constraint<Lecture,Placement>>, CanHoldContext, HasAssignmentContext<Lecture,Placement,FlexibleConstraint.FlexibleConstraintContext>

public class MaxHalfDaysFlexibleConstraint
extends FlexibleConstraint

The MaxHalfDays constraint limits the number of half-days of week during which the given set of classes are taught.
It has one parameter: a maximal number of week half-days during which the given set of classes can be placed.
A day is split by noon (which can be changed using General.HalfDaySlot parameter). A class starting before noon is considered a morning class (despite of its end), a class starting at noon or later is considered an afternoon class.
Reference _MaxHalfDays:4_ translates to a maximum number of 4 half-days a week

Version:

CourseTT 1.3 (University Course Timetabling)
Copyright (C) 2017 Tomáš Müller

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	MaxHalfDaysFlexibleConstraint.MaxHalfDaysFlexibleConstraintContext

Nested classes/interfaces inherited from class org.cpsolver.coursett.constraint.FlexibleConstraint

FlexibleConstraint.Block, FlexibleConstraint.FlexibleConstraintContext, FlexibleConstraint.FlexibleConstraintType, FlexibleConstraint.PlacementTimeComparator

Field Summary

Fields inherited from class org.cpsolver.coursett.constraint.FlexibleConstraint

iConstraintType, iDayOfWeekOffset, iPreciseDateComputation, iPreference, iReference, iWeeks

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
MaxHalfDaysFlexibleConstraint(Long id, String owner, String preference, String reference)

Method Summary

Modifier and Type	Method and Description
void	computeConflicts(Assignment<Lecture,Placement> assignment, Placement value, Set<Placement> conflicts) The only method which has to be implemented by any constraint.
FlexibleConstraint.FlexibleConstraintContext	createAssignmentContext(Assignment<Lecture,Placement> assignment) Create a new assignment context for the given assignment.
protected int	getHalfDay(TimeLocation time) Returns index of the half day
protected int	getNrHalfDays() Returns number of half-days in a day
double	getNrViolations(Assignment<Lecture,Placement> assignment, Set<Placement> conflicts, HashMap<Lecture,Placement> assignments) Return current number of violations.
boolean	inConflict(Assignment<Lecture,Placement> assignment, Placement value) Returns true if the given assignment is inconsistent with the existing assignments respecting this constraint.
void	setModel(Model<Lecture,Placement> model) Sets the model which the constraint belongs to

Methods inherited from class org.cpsolver.coursett.constraint.FlexibleConstraint

getCurrentPreference, getDayOfWeekOffset, getName, getOwner, getPrologPreference, getReference, getRelevantPlacements, getType, getWeeks, isConsistent, isHard, isPreciseDateComputation, mergeToBlocks, shareWeeksAndDay, toString

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

assigned, getAssignmentContextReference, getContext, getContext, setAssignmentContextReference, unassigned

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxHalfDaysFlexibleConstraint

public MaxHalfDaysFlexibleConstraint(Long id,
                                     String owner,
                                     String preference,
                                     String reference)

Method Detail

setModel

public void setModel(Model<Lecture,Placement> model)

Description copied from class: Constraint

Sets the model which the constraint belongs to

Overrides:

setModel in class ConstraintWithContext<Lecture,Placement,FlexibleConstraint.FlexibleConstraintContext>

Parameters:

model - problem model

getNrHalfDays

protected int getNrHalfDays()

Returns number of half-days in a day

getHalfDay

protected int getHalfDay(TimeLocation time)

Returns index of the half day

Parameters:

time - given time

Returns:

0 for morning, 1 for evening

getNrViolations

public double getNrViolations(Assignment<Lecture,Placement> assignment,
                              Set<Placement> conflicts,
                              HashMap<Lecture,Placement> assignments)

Description copied from class: FlexibleConstraint

Return current number of violations.

Specified by:

getNrViolations in class FlexibleConstraint

Parameters:

assignment - current assignment

conflicts - conflicting placements to be unassigned

assignments - assigned placements

Returns:

the number of violations of the constraint during days and all weeks of the semester

computeConflicts

public void computeConflicts(Assignment<Lecture,Placement> assignment,
                             Placement value,
                             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

value - value to be assigned to its variable

conflicts - resultant set of conflicting values

inConflict

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

Parameters:

assignment - current assignment

value - given value

Returns:

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

createAssignmentContext

public FlexibleConstraint.FlexibleConstraintContext 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,FlexibleConstraint.FlexibleConstraintContext>

Overrides:

createAssignmentContext in class FlexibleConstraint

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