Package org.jacop.constraints

Class ExtensionalConflictVA

  • All Implemented Interfaces:
    Stateful, UsesQueueVariable
    public class ExtensionalConflictVA
extends Constraint
implements UsesQueueVariable, Stateful
    Extensional constraint assures that none of the tuples explicitly given is enforced in the relation.

    This implementation tries to balance the usage of memory versus time efficiency.

    Version:
    4.8

    • Field Detail

      • idNumber

        static java.util.concurrent.atomic.AtomicInteger idNumber

      • numberTuples

        int numberTuples

      • tuples

        int[][][][] tuples
        It represents tuples which are supports for each of the variables. The first index denotes variable index. The second index denotes value index. The third index denotes tuple.

      • tuplesFromConstructor

        public int[][] tuplesFromConstructor
        It specifies the tuples given in the constructor.

      • values

        int[][] values
        It represents values which are supported for a variable.

      • variableQueue

        java.util.LinkedHashSet<Var> variableQueue

      • list

        public IntVar[] list
        It stores variables within this extensional constraint, order does matter.

      • satisfiedAlreadyAtImposition

        private boolean satisfiedAlreadyAtImposition

      • tuple

        int[] tuple

      • lastofsequence

        int[][][] lastofsequence

      • supports

        int[][][] supports

    • Constructor Detail

      • ExtensionalConflictVA

        @Deprecated
public ExtensionalConflictVA​(IntVar[] list)
        Deprecated.
        Partial constructor which stores variables involved in a constraint but does not get information about tuples yet. The tuples must set separately.
        Parameters:
        list - list of variables for constraint

      • ExtensionalConflictVA

        public ExtensionalConflictVA​(IntVar[] list,
                             int[][] tuples)
        Constructor stores reference to tuples until imposition, any changes to tuples parameter will be reflected in the constraint behavior. Changes to tuples should not performed under any circumstances. The tuples array is not copied to save memory and time.
        Parameters:
        list - list of variables for the conflict constraint
        tuples - list of forbidden tuples

      • ExtensionalConflictVA

        public ExtensionalConflictVA​(java.util.List<? extends IntVar> variables,
                             int[][] tuples)
        The constructor does not create local copy of tuples array. Any changes to this array will reflect on constraint behavior. Most probably incorrect as other data structures will not change accordingly.
        Parameters:
        variables - the scope of the extensional conflict constraint.
        tuples - the conflict (forbidden) tuples for that constraint.

    • Method Detail

      • seekSupportVA

        public int[] seekSupportVA​(int varPosition,
                           int value)
        It seeks support tuple for a given variable and its value.
        Parameters:
        varPosition - variable for which the support is seeked.
        value - value of the variable for which support is seeked.
        Returns:
        support tuple supporting varPosition-value pair.

      • recordSupport

        private void recordSupport​(int varPosition,
                           int value,
                           int[] t)

      • setFirstValid

        public int[] setFirstValid​(int varPosition,
                           int value)
        It computes the first valid tuple given restriction that a variable will be equal to a given value.
        Parameters:
        varPosition - the position of the variable.
        value - the value of the variable.
        Returns:
        the smallest valid tuple supporting varPosition-value pair.

      • isDisallowed

        public int isDisallowed​(int varPosition,
                        int value,
                        int[] t)
        It returns the position of disallowed tuple in the array of tuples for a given variable-value pair.
        Parameters:
        varPosition - variable for which we search for the forbidden tuple.
        value - value for which we search for the forbidden tuple.
        t - tuple which we check for forbidness.
        Returns:
        position of the forbidden tuple, -1 if it is not forbidden.

      • seekInvalidPosition

        public int seekInvalidPosition​(int[] t)
        It finds the position at which the tuple is invalid. The value is not in the domain of the corresponding variable.
        Parameters:
        t - tuple being check for in-validity
        Returns:
        the position in the tuple at which the corresponding variable does not contain the value used by tuple, -1 if no invalid position exists.

      • removeLevel

        public void removeLevel​(int level)
        It puts back tuples which have lost their support status at the level which is being removed.
        Specified by:
        removeLevel in interface Stateful
        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.

      • findPosition

        protected int findPosition​(int value,
                           int[] values)

      • impose

        public void impose​(Store store)
        Description copied from class: Constraint
        It imposes the constraint in a given store.
        Overrides:
        impose in class Constraint
        Parameters:
        store - the constraint store to which the constraint is imposed to.

      • computeLastOfSequence

        private int computeLastOfSequence​(int[][] is,
                                  int posVar,
                                  int l)

      • queueVariable

        public void queueVariable​(int level,
                          Var var)
        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.
        var - variable which has changed.

      • smaller

        boolean smaller​(int[] tuple1,
                int[] tuple2)

      • equal

        boolean equal​(int[] tuple1,
              int[] tuple2)

      • toString

        public java.lang.String toString()
        Description copied from class: Constraint
        It produces a string representation of a constraint state.
        Overrides:
        toString in class Constraint