Package org.jacop.constraints.netflow

Class ArcCompanion

  • All Implemented Interfaces:
    java.lang.Comparable<ArcCompanion>, VarHandler
    public final class ArcCompanion
extends java.lang.Object
implements VarHandler, java.lang.Comparable<ArcCompanion>
    This class extends the definition of an arc by a lower bound on the capacity and connects the arc to variables that constrain it.

    The ArcCompanion plays the role of the VarHandler for X- and W-variables. It also provides a hook for S-variables of any

    Version:
    4.8

    • Constructor Summary

      Constructors 
      Constructor Description
      ArcCompanion​(Arc arc, int offset)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void changeCapacity​(int min, int max)
      Changes the lower and upper capacity of the arc in any way, performing the necessary changes to node balance and flow offset functions.
      void changeMaxCapacity​(int max)  
      void changeMinCapacity​(int min)  
      int compareTo​(ArcCompanion that)  
      int getPruningEvent​(Var var)
      Retrieves the consistency pruning event of a handler variable that causes the handler to be reevaluated.
      java.util.List<IntVar> listVariables()  
      void processEvent​(IntVar variable, MutableNetwork network)
      Informs the handler that one of its variable has changed and asks the handler to update the state of the network accordingly.
      void restore​(MutableNetwork network)
      Restores the capacity and weight of the arc after backtracking.
      void setFlow​(int flow)
      Forces the flow to a given value (within capacity bounds).
      java.lang.String toString()  
      private boolean updateSVar​(int level)
      interaction with structure variable

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • arc

        public final Arc arc
        The (forward) arc

      • flowOffset

        public int flowOffset
        Current lower capacity of the arc

      • xVar

        public IntVar xVar
        The FDV for lower and upper capacity

      • wVar

        public IntVar wVar
        The FDV for lower and upper cost

      • structure

        public DomainStructure structure
        The associated structure variable

      • arcID

        public int arcID
        Identifier for this arc in the structure variable

      • pruningScore

        public int pruningScore
        The pruningScore

    • Constructor Detail

      • ArcCompanion

        public ArcCompanion​(Arc arc,
                    int offset)

    • Method Detail

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • changeCapacity

        public void changeCapacity​(int min,
                           int max)
        Changes the lower and upper capacity of the arc in any way, performing the necessary changes to node balance and flow offset functions.
        Parameters:
        min - the new lower capacity
        max - the new upper capacity

      • changeMinCapacity

        public void changeMinCapacity​(int min)

      • changeMaxCapacity

        public void changeMaxCapacity​(int max)

      • listVariables

        public java.util.List<IntVar> listVariables()
        Specified by:
        listVariables in interface VarHandler
        Returns:
        the list of variables handled by this handler

      • processEvent

        public void processEvent​(IntVar variable,
                         MutableNetwork network)
        Description copied from interface: VarHandler
        Informs the handler that one of its variable has changed and asks the handler to update the state of the network accordingly.
        Specified by:
        processEvent in interface VarHandler
        Parameters:
        variable - the variable that changed
        network - the network

      • restore

        public void restore​(MutableNetwork network)
        Restores the capacity and weight of the arc after backtracking.
        Parameters:
        network - the network

      • setFlow

        public void setFlow​(int flow)
        Forces the flow to a given value (within capacity bounds).
        Parameters:
        flow - the new flow value

      • getPruningEvent

        public int getPruningEvent​(Var var)
        Description copied from interface: VarHandler
        Retrieves the consistency pruning event of a handler variable that causes the handler to be reevaluated. For instance, X- and W-variables will listen to BOUND events while S-variables typically consider ANY events.
        Specified by:
        getPruningEvent in interface VarHandler
        Parameters:
        var - a handler variable
        Returns:
        the pruning event which causes reevaluation of the handler

      • updateSVar

        private boolean updateSVar​(int level)
        interaction with structure variable
        Parameters:
        level - current store level
        Returns:
        whether the domain of the s-variable has been updated

      • compareTo

        public int compareTo​(ArcCompanion that)
        Specified by:
        compareTo in interface java.lang.Comparable<ArcCompanion>