org.jacop.constraints

Class Diff

java.lang.Object

org.jacop.constraints.DecomposedConstraint

org.jacop.constraints.Constraint

org.jacop.constraints.Diff

Direct Known Subclasses:

Diff2, Disjoint, DisjointConditional

public class Diff
extends Constraint

Diff constraint assures that any two rectangles from a vector of rectangles does not overlap in at least one direction. It is a simple implementation which does not use sophisticated techniques for efficient backtracking.

Version:

3.1

Author:

Krzysztof Kuchcinski and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
boolean	doProfile It specifies if the constraint should compute and use the profile.
Rectangle[]	rectangles It specifies the list of rectangles which are of interest for this diff constraint.
static String[]	xmlAttributes It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.

Fields inherited from class org.jacop.constraints.Constraint

atomicExecution, consistencyPruningEvents, earlyTerminationOK, id, increaseWeight, numberArgs, numberId

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Constructor and Description
Diff(ArrayList<? extends ArrayList<? extends IntVar>> rectangles) It specifies a diffn constraint.
Diff(ArrayList<? extends ArrayList<? extends IntVar>> rectangles, boolean profile) It specifies a diff constraint.
Diff(ArrayList<? extends IntVar> o1, ArrayList<? extends IntVar> o2, ArrayList<? extends IntVar> l1, ArrayList<? extends IntVar> l2) It constructs a diff constraint.
Diff(ArrayList<? extends IntVar> o1, ArrayList<? extends IntVar> o2, ArrayList<? extends IntVar> l1, ArrayList<? extends IntVar> l2, boolean profile) It constructs a diff constraint.
Diff(IntVar[][] rectangles) It specifies a diff constraint.
Diff(IntVar[][] rectangles, boolean profile) It specifies a diff constraint.
Diff(IntVar[] origin1, IntVar[] origin2, IntVar[] length1, IntVar[] length2) It constructs a diff constraint.
Diff(IntVar[] o1, IntVar[] o2, IntVar[] l1, IntVar[] l2, boolean profile) It constructs a diff constraint.
Diff(Rectangle[] rectangles, boolean doProfile) It specifies a diff constraint.

Method Summary

Modifier and Type	Method and Description
ArrayList<Var>	arguments() It returns the variables in a scope of the constraint.
void	consistency(Store store) It is a (most probably incomplete) consistency function which removes the values from variables domains.
int	getConsistencyPruningEvent(Var var) It retrieves the pruning event which causes reevaluation of the constraint.
String	id() It gives the id string of a constraint.
void	impose(Store store) It imposes the constraint in a given store.
void	increaseWeight() It increases the weight of the variables in the constraint scope.
void	queueVariable(int level, Var V) This is a function called to indicate which variable in a scope of constraint has changed.
void	removeConstraint() It removes the constraint by removing this constraint from all variables.
void	removeLevel(int level) This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid.
boolean	satisfied() It checks if the constraint is satisfied.
String	toString() It produces a string representation of a constraint state.

Methods inherited from class org.jacop.constraints.Constraint

cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, impose, imposeDecomposition, numberArgs, removeLevelLate, requiresMonotonicity, setConsistencyPruningEvent, supplyGuideFeedback

Methods inherited from class org.jacop.constraints.DecomposedConstraint

auxiliaryVariables, derivative, imposeDecomposition

Methods inherited from class java.lang.Object

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

Field Detail

rectangles

public Rectangle[] rectangles

It specifies the list of rectangles which are of interest for this diff constraint.

doProfile

public boolean doProfile

It specifies if the constraint should compute and use the profile.

xmlAttributes

public static String[] xmlAttributes

It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.

Constructor Detail

Diff

public Diff(Rectangle[] rectangles,
            boolean doProfile)

It specifies a diff constraint.

Parameters:

rectangles - list of rectangles which can not overlap in at least one dimension.

doProfile - should the constraint compute and use the profile functionality.

Diff

public Diff(IntVar[][] rectangles)

It specifies a diff constraint.

Parameters:

rectangles - list of rectangles which can not overlap in at least one dimension.

Diff

public Diff(IntVar[] o1,
            IntVar[] o2,
            IntVar[] l1,
            IntVar[] l2,
            boolean profile)

It constructs a diff constraint.

Parameters:

o1 - list of variables denoting origin of the rectangle in the first dimension.

o2 - list of variables denoting origin of the rectangle in the second dimension.

l1 - list of variables denoting length of the rectangle in the first dimension.

l2 - list of variables denoting length of the rectangle in the second dimension.

profile - it specifies if the profile should be computed and used.

Diff

public Diff(IntVar[] origin1,
            IntVar[] origin2,
            IntVar[] length1,
            IntVar[] length2)

It constructs a diff constraint.

Parameters:

origin1 - list of variables denoting origin of the rectangle in the first dimension.

origin2 - list of variables denoting origin of the rectangle in the second dimension.

length1 - list of variables denoting length of the rectangle in the first dimension.

length2 - list of variables denoting length of the rectangle in the second dimension.

Diff

public Diff(ArrayList<? extends ArrayList<? extends IntVar>> rectangles)

It specifies a diffn constraint.

Parameters:

rectangles - list of rectangles which can not overlap in at least one dimension.

Diff

public Diff(ArrayList<? extends ArrayList<? extends IntVar>> rectangles,
            boolean profile)

It specifies a diff constraint.

Parameters:

profile - specifies is the profiles are used.

rectangles - list of rectangles which can not overlap in at least one dimension.

Diff

public Diff(ArrayList<? extends IntVar> o1,
            ArrayList<? extends IntVar> o2,
            ArrayList<? extends IntVar> l1,
            ArrayList<? extends IntVar> l2)

It constructs a diff constraint.

Parameters:

o1 - list of variables denoting origin of the rectangle in the first dimension.

o2 - list of variables denoting origin of the rectangle in the second dimension.

l1 - list of variables denoting length of the rectangle in the first dimension.

l2 - list of variables denoting length of the rectangle in the second dimension.

Diff

public Diff(ArrayList<? extends IntVar> o1,
            ArrayList<? extends IntVar> o2,
            ArrayList<? extends IntVar> l1,
            ArrayList<? extends IntVar> l2,
            boolean profile)

It constructs a diff constraint.

Parameters:

o1 - list of variables denoting origin of the rectangle in the first dimension.

o2 - list of variables denoting origin of the rectangle in the second dimension.

l1 - list of variables denoting length of the rectangle in the first dimension.

l2 - list of variables denoting length of the rectangle in the second dimension.

profile - it specifies if the profile should be computed and used.

Diff

public Diff(IntVar[][] rectangles,
            boolean profile)

It specifies a diff constraint.

Parameters:

profile - specifies is the profiles are used.

rectangles - list of rectangles which can not overlap in at least one dimension.

Method Detail

arguments

public ArrayList<Var> arguments()

Description copied from class: Constraint

It returns the variables in a scope of the constraint.

Specified by:

arguments in class Constraint

Returns:

variables in a scope of the constraint.

removeLevel

public void removeLevel(int level)

Description copied from class: Constraint

This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid. This function is called *before* all timestamps, variables, mutablevariables have reverted to their previous value.

Overrides:

removeLevel in class Constraint

Parameters:

level - the level which is being removed.

consistency

public void consistency(Store store)

Description copied from class: Constraint

It is a (most probably incomplete) consistency function which removes the values from variables domains. Only values which do not have any support in a solution space are removed.

Specified by:

consistency in class Constraint

Parameters:

store - constraint store within which the constraint consistency is being checked.

getConsistencyPruningEvent

public int getConsistencyPruningEvent(Var var)

Description copied from class: Constraint

It retrieves the pruning event which causes reevaluation of the constraint.

Specified by:

getConsistencyPruningEvent in class Constraint

Parameters:

var - variable for which pruning event is retrieved

Returns:

it returns the int code of the pruning event (GROUND, BOUND, ANY, NONE)

id

public String id()

Description copied from class: Constraint

It gives the id string of a constraint.

Overrides:

id in class Constraint

Returns:

string id of the constraint.

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Specified by:

impose in class Constraint

Parameters:

store - the constraint store to which the constraint is imposed to.

queueVariable

public void queueVariable(int level,
                          Var V)

Description copied from class: Constraint

This is a function called to indicate which variable in a scope of constraint has changed. It also indicates a store level at which the change has occurred.

Overrides:

queueVariable in class Constraint

Parameters:

level - the level of the store at which the change has occurred.

V - variable which has changed.

removeConstraint

public void removeConstraint()

Description copied from class: Constraint

It removes the constraint by removing this constraint from all variables.

Specified by:

removeConstraint in class Constraint

satisfied

public boolean satisfied()

Description copied from class: Constraint

It checks if the constraint is satisfied. If this function is incorrectly implemented a constraint may not be satisfied in a solution.

Specified by:

satisfied in class Constraint

Returns:

true if the constraint is for certain satisfied, false otherwise.

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Specified by:

toString in class Constraint

increaseWeight

public void increaseWeight()

Description copied from class: Constraint

It increases the weight of the variables in the constraint scope.

Specified by:

increaseWeight in class Constraint