choco.palm.search
Class AbstractDecision

java.lang.Object
  choco.AbstractEntity
      choco.palm.search.AbstractDecision

All Implemented Interfaces:

Constraint, Entity, DecisionConstraint, PalmConstraint, PalmVarListener, SymbolicDecision, VarEventListener, Propagator, java.lang.Cloneable, java.util.EventListener

Direct Known Subclasses:

Assignment

public abstract class AbstractDecision
extends AbstractEntity
implements DecisionConstraint

A class representing a decision as a constraint (An adapter of decision constraint). It is useful to represent decision in a uniform way when the search algorithm performs assignments instead of posting constraints (As done by the AssignVar branching).

Field Summary

Fields inherited from class choco.AbstractEntity

hook, problem

Constructor Summary

AbstractDecision(AbstractProblem problem)

Method Summary

void	activateListener()
void	addListener(boolean dynamicAddition) This function connects a constraint with its variables in several ways.
int	assignIndices(AbstractCompositeConstraint root, int i, boolean dynamicAddition) performs the global numbering (wrt root) of the variables contained in the subtree this, starting from i
void	awake() Propagation: Propagating the constraint for the very first time until local consistency is reached.
void	awakeOnVar(int idx) propagation on domain revision.
java.lang.Object	clone() returns a copy of the constraint.
void	deactivateListener()
void	deactivateListener(int varIndex)
int	getConstraintIdx(int idx) Network management: Among all listeners linked to the idx-th variable of c, find the index of constraint c.
PropagationEvent	getEvent() Returns the constraint awake var associated with this constraint.
ConstraintPlugin	getPlugIn() Returns the constraint plugin.
int	getPriority() Propagation: Accessing the priority level of the queue handling the propagation of the constraint.
int	getVarIdxInOpposite(int i) computes the index of the i-th variable in the counter-opposite of the constraint
boolean	isActive() Propagation: A constraint is active if it is connected to the network and if it does propagate.
boolean	isConsistent() tests if the constraint is consistent with respect to the current state of domains
java.lang.Boolean	isEntailed() Checks whether the constraint is definitely satisfied, no matter what further restrictions occur to the domain of its variables.
boolean	isEquivalentTo(Constraint compareTo) tests the equivalence (logical equality of the conditions) between two constraints.
Constraint	negate() Returns the negation of this enumeration constraint.
AbstractConstraint	opposite() computes the constraint modelling the counter-opposite condition of this
void	propagate() Propagation: Propagating the constraint until local consistency is reached.
void	setActive() Propagation: un-freezes a constraint [a constraint is active if it is connected to the network and if it does propagate]
void	setConstraintIndex(int i, int idx) Network management: Storing that among all listeners linked to the i-th variable of c, this (the current constraint) is found at index idx.
void	setPassive() Propagation: freezes a constraint [a constraint is active if it is connected to the network and if it does propagate]
void	takeIntoAccountStatusChange(int index) Informs constraints that one of their children has a modified status (due to value restoration).
void	updateDataStructuresOnConstraint(int idx, int select, int newValue, int oldValue) Method called when one of the variables is modified.
void	updateDataStructuresOnRestoreConstraint(int idx, int select, int newValue, int oldValue) Method called when one of the variables has a restored value.

Methods inherited from class choco.AbstractEntity

getProblem, pretty

Methods inherited from class java.lang.Object

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

Methods inherited from interface choco.palm.dbt.search.DecisionConstraint

getBranch

Constructor Detail

AbstractDecision

public AbstractDecision(AbstractProblem problem)

Method Detail

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Description copied from interface: Constraint

returns a copy of the constraint. This copy is a new object, may be a recursive copy in case of composite constraints. The original and the copy share the same variables & plugins

Specified by:

clone in interface Constraint

Overrides:

clone in class java.lang.Object

Returns:

Throws:

java.lang.CloneNotSupportedException

getPlugIn

public ConstraintPlugin getPlugIn()

Description copied from interface: Propagator

Returns the constraint plugin. Useful for extending the solver.

Specified by:

getPlugIn in interface Propagator

takeIntoAccountStatusChange

public void takeIntoAccountStatusChange(int index)

Description copied from interface: PalmConstraint

Informs constraints that one of their children has a modified status (due to value restoration).

Specified by:

takeIntoAccountStatusChange in interface PalmConstraint

updateDataStructuresOnConstraint

public void updateDataStructuresOnConstraint(int idx,
                                             int select,
                                             int newValue,
                                             int oldValue)

Description copied from interface: PalmVarListener

Method called when one of the variables is modified.

Specified by:

updateDataStructuresOnConstraint in interface PalmVarListener

Parameters:

idx - Index of the variable.

select - Type of modification (PalmIntVar.INF, PalmIntVar.SUP, PalmIntVar.VAL).

newValue - New value (or modified value).

oldValue - Old value (or 0 if this a value removal).

updateDataStructuresOnRestoreConstraint

public void updateDataStructuresOnRestoreConstraint(int idx,
                                                    int select,
                                                    int newValue,
                                                    int oldValue)

Description copied from interface: PalmVarListener

Method called when one of the variables has a restored value.

Specified by:

updateDataStructuresOnRestoreConstraint in interface PalmVarListener

Parameters:

idx - Index of the variable.

select - Type of modification.

newValue - New value (or modified value).

oldValue - Old value (or 0 if this a value removal).

negate

public Constraint negate()

Description copied from interface: DecisionConstraint

Returns the negation of this enumeration constraint.

Specified by:

negate in interface DecisionConstraint

addListener

public void addListener(boolean dynamicAddition)

Description copied from interface: VarEventListener

This function connects a constraint with its variables in several ways. Note that it may only be called once the constraint has been fully created and is being posted to a problem. Note that it should be called only once per constraint. This can be a dynamic addition (undone upon backtracking) or not

Specified by:

addListener in interface VarEventListener

deactivateListener

public void deactivateListener(int varIndex)

deactivateListener

public void deactivateListener()

activateListener

public void activateListener()

setConstraintIndex

public void setConstraintIndex(int i,
                               int idx)

Description copied from interface: Constraint

Network management: Storing that among all listeners linked to the i-th variable of c, this (the current constraint) is found at index idx.

Specified by:

setConstraintIndex in interface Constraint

Specified by:

setConstraintIndex in interface PalmVarListener

Parameters:

i - index of the variable in the constraint

idx - index of the constraint in the among all listeners linked to that variable

getConstraintIdx

public int getConstraintIdx(int idx)

Description copied from interface: Constraint

Network management: Among all listeners linked to the idx-th variable of c, find the index of constraint c.

Specified by:

getConstraintIdx in interface Constraint

Specified by:

getConstraintIdx in interface PalmVarListener

Parameters:

idx - index of the variable in the constraint

awake

public void awake()
           throws ContradictionException

Description copied from interface: Propagator

Propagation: Propagating the constraint for the very first time until local consistency is reached.

Specified by:

awake in interface Propagator

Throws:

ContradictionException

awakeOnVar

public void awakeOnVar(int idx)
                throws ContradictionException

Description copied from interface: VarEventListener

propagation on domain revision.

Specified by:

awakeOnVar in interface VarEventListener

Specified by:

awakeOnVar in interface Propagator

Throws:

ContradictionException

propagate

public void propagate()
               throws ContradictionException

Description copied from interface: Propagator

Propagation: Propagating the constraint until local consistency is reached.

Specified by:

propagate in interface Propagator

Throws:

ContradictionException

getPriority

public int getPriority()

Description copied from interface: Propagator

Propagation: Accessing the priority level of the queue handling the propagation of the constraint. Results range from 1 (most reactive, for listeners with fast propagation algorithms) to 4 (most delayed, for listeners with lengthy propagation algorithms).

Specified by:

getPriority in interface Propagator

isActive

public boolean isActive()

Description copied from interface: VarEventListener

Propagation: A constraint is active if it is connected to the network and if it does propagate.

Specified by:

isActive in interface VarEventListener

setActive

public void setActive()

Description copied from interface: VarEventListener

Propagation: un-freezes a constraint [a constraint is active if it is connected to the network and if it does propagate]

Specified by:

setActive in interface VarEventListener

setPassive

public void setPassive()

Description copied from interface: VarEventListener

Propagation: freezes a constraint [a constraint is active if it is connected to the network and if it does propagate]

Specified by:

setPassive in interface VarEventListener

getEvent

public PropagationEvent getEvent()

Description copied from interface: Propagator

Returns the constraint awake var associated with this constraint.

Specified by:

getEvent in interface Propagator

isEntailed

public java.lang.Boolean isEntailed()

Description copied from interface: Propagator

Checks whether the constraint is definitely satisfied, no matter what further restrictions occur to the domain of its variables.

Specified by:

isEntailed in interface Propagator

isConsistent

public boolean isConsistent()

Description copied from interface: Propagator

tests if the constraint is consistent with respect to the current state of domains

Specified by:

isConsistent in interface Propagator

getVarIdxInOpposite

public int getVarIdxInOpposite(int i)

Description copied from interface: Constraint

computes the index of the i-th variable in the counter-opposite of the constraint

Specified by:

getVarIdxInOpposite in interface Constraint

Parameters:

i - the index of the variable in the current constraint (this)

Returns:

the index of the variable in the opposite constraint (this.opposite())

opposite

public AbstractConstraint opposite()

Description copied from interface: Constraint

computes the constraint modelling the counter-opposite condition of this

Specified by:

opposite in interface Constraint

Returns:

a new constraint (modelling the opposite condition)

isEquivalentTo

public boolean isEquivalentTo(Constraint compareTo)

Description copied from interface: Constraint

tests the equivalence (logical equality of the conditions) between two constraints. In particular whenever c1.equals(c2), then c1.isEquivalent(c2).

Specified by:

isEquivalentTo in interface Constraint

Parameters:

compareTo - the constraint to be compared to

Returns:

true if and only if the constraints model the same logical condition.

assignIndices

public int assignIndices(AbstractCompositeConstraint root,
                         int i,
                         boolean dynamicAddition)

Description copied from interface: Propagator

performs the global numbering (wrt root) of the variables contained in the subtree this, starting from i

Specified by:

assignIndices in interface Propagator

Parameters:

root - the overall root constraint, for which the variables are numbered

i - the index that will assigned to the first variable in the subtree this (originally 0)

dynamicAddition - whether the addition is undone automatically on backtracking

Returns:

the index of the last variable in the subtree