Package org.jacop.constraints

Class Assignment

java.lang.Object
org.jacop.constraints.DecomposedConstraint<Constraint>
org.jacop.constraints.Constraint
org.jacop.constraints.Assignment
All Implemented Interfaces:
SatisfiedPresent, Stateful, UsesQueueVariable
public class Assignment extends Constraint implements UsesQueueVariable, Stateful, SatisfiedPresent
Assignment constraint implements facility to improve channeling constraints between dual viewpoints of permutation models. It enforces the relationship x[d[i]-shiftX]=i+shiftD and d[x[i]-shiftD]=i+shiftX.
Version:
4.10

  • Field Details

    • idNumber

      static final AtomicInteger idNumber

    • d

      public final IntVar[] d
      It specifies a list of variables d.

    • shiftD

      public int shiftD
      It specifies a shift applied to variables d.

    • ds

      Map<IntVar,Integer> ds

    • x

      public IntVar[] x
      It specifies a list of variables x.

    • shiftX

      public int shiftX
      It specifies a shift applied to variables x.

    • xs

      Map<IntVar,Integer> xs

    • variableQueue

      LinkedHashSet<IntVar> variableQueue

    • firstConsistencyCheck

      boolean firstConsistencyCheck

    • firstConsistencyLevel

      int firstConsistencyLevel

    • rangeX

      IntervalDomain rangeX

    • rangeD

      IntervalDomain rangeD

  • Constructor Details

    • Assignment

      public Assignment(IntVar[] xs, IntVar[] ds, int shiftX, int shiftD)
      It enforces the relationship x[d[i]-shiftX]=i+shiftD and d[x[i]-shiftD]=i+shiftX.
      Parameters:
      xs - array of variables x
      ds - array of variables d
      shiftX - a shift of indexes in X array.
      shiftD - a shift of indexes in D array.

    • Assignment

      public Assignment(List<? extends IntVar> xs, List<? extends IntVar> ds, int shiftX, int shiftD)
      It enforces the relationship x[d[i]-shiftX]=i+shiftD and d[x[i]-shiftD]=i+shiftX.
      Parameters:
      xs - arraylist of variables x
      ds - arraylist of variables d
      shiftX - shift for parameter xs
      shiftD - shift for parameter ds

    • Assignment

      public Assignment(List<? extends IntVar> xs, List<? extends IntVar> ds)
      It constructs an Assignment constraint with shift equal 0. It enforces relation - d[x[j]] = i and x[d[i]] = j.
      Parameters:
      xs - arraylist of x variables
      ds - arraylist of d variables

    • Assignment

      public Assignment(List<? extends Var> xs, List<? extends Var> ds, int min)
      It enforces the relationship x[d[i]-min]=i+min and d[x[i]-min]=i+min.
      Parameters:
      xs - arraylist of variables x
      ds - arraylist of variables d
      min - shift

    • Assignment

      public Assignment(IntVar[] xs, IntVar[] ds)
      It constructs an Assignment constraint with shift equal 0. It enforces relation - d[x[i]] = i and x[d[i]] = i.
      Parameters:
      xs - array of x variables
      ds - array of d variables

    • Assignment

      public Assignment(IntVar[] xs, IntVar[] ds, int min)
      It enforces the relationship x[d[i]-min]=i+min and d[x[i]-min]=i+min.
      Parameters:
      xs - array of variables x
      ds - array of variables d
      min - shift

  • Method Details

    • removeLevel

      public void removeLevel(int level)
      Description copied from interface: Stateful
      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.
      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.

    • satisfied

      public boolean satisfied()
      Description copied from interface: SatisfiedPresent
      It checks if the constraint is satisfied. It can return false even if constraint is satisfied but not all variables in its scope are grounded. It needs to return true if all variables in its scope are grounded and constraint is satisfied.

      Implementations of this interface for constraints that are not PrimitiveConstraint may require constraint imposition and consistency check as a requirement to work correctly.

      Specified by:
      satisfied in interface SatisfiedPresent
      Returns:
      true if constraint is possible to verify that it is satisfied.

    • getDefaultConsistencyPruningEvent

      public int getDefaultConsistencyPruningEvent()
      Specified by:
      getDefaultConsistencyPruningEvent in class Constraint

    • 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.

    • 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.

    • toString

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