Package com.google.ortools.constraintsolver

Class PathOperator

java.lang.Object
com.google.ortools.constraintsolver.BaseObject
com.google.ortools.constraintsolver.LocalSearchOperator
com.google.ortools.constraintsolver.IntVarLocalSearchOperator
com.google.ortools.constraintsolver.PathOperator
public class PathOperator extends IntVarLocalSearchOperator
Base class of the local search operators dedicated to path modifications
(a path is a set of nodes linked together by arcs).
This family of neighborhoods supposes they are handling next variables
representing the arcs (var[i] represents the node immediately after i on
a path).
Several services are provided:
- arc manipulators (SetNext(), ReverseChain(), MoveChain())
- path inspectors (Next(), Prev(), IsPathEnd())
- path iterators: operators need a given number of nodes to define a
neighbor; this class provides the iteration on a given number of (base)
nodes which can be used to define a neighbor (through the BaseNode method)
Subclasses only need to override MakeNeighbor to create neighbors using
the services above (no direct manipulation of assignments).

  • Constructor Details

  • Method Details

    • getCPtr

      protected static long getCPtr(PathOperator obj)

    • swigRelease

      protected static long swigRelease(PathOperator obj)

    • finalize

      protected void finalize()
      Overrides:
      finalize in class IntVarLocalSearchOperator

    • delete

      public void delete()
      Overrides:
      delete in class IntVarLocalSearchOperator

    • swigDirectorDisconnect

      protected void swigDirectorDisconnect()
      Overrides:
      swigDirectorDisconnect in class IntVarLocalSearchOperator

    • swigReleaseOwnership

      public void swigReleaseOwnership()
      Overrides:
      swigReleaseOwnership in class IntVarLocalSearchOperator

    • swigTakeOwnership

      public void swigTakeOwnership()
      Overrides:
      swigTakeOwnership in class IntVarLocalSearchOperator

    • neighbor

      public boolean neighbor()

    • reset

      public void reset()
      Overrides:
      reset in class LocalSearchOperator

    • Prev

      public long Prev(long node)
      Returns the node before node in the current delta.

    • oneNeighbor

      protected boolean oneNeighbor()
      This method should not be overridden. Override MakeNeighbor() instead.
      Overrides:
      oneNeighbor in class IntVarLocalSearchOperator

    • OnNodeInitialization

      protected void OnNodeInitialization()
      Called by OnStart() after initializing node information. Should be
      overridden instead of OnStart() to avoid calling PathOperator::OnStart
      explicitly.

    • restartAtPathStartOnSynchronize

      protected boolean restartAtPathStartOnSynchronize()
      When the operator is being synchronized with a new solution (when Start()
      is called), returns true to restart the exploration of the neighborhood
      from the start of the last paths explored; returns false to restart the
      exploration at the last nodes visited.
      This is used to avoid restarting on base nodes which have changed paths,
      leading to potentially skipping neighbors.

    • onSamePathAsPreviousBase

      protected boolean onSamePathAsPreviousBase(long base_index)
      Returns true if a base node has to be on the same path as the "previous"
      base node (base node of index base_index - 1).
      Useful to limit neighborhood exploration to nodes on the same path.
      it's currently way more complicated to implement.

    • getBaseNodeRestartPosition

      protected long getBaseNodeRestartPosition(int base_index)
      Returns the index of the node to which the base node of index base_index
      must be set to when it reaches the end of a path.
      By default, it is set to the start of the current path.
      When this method is called, one can only assume that base nodes with
      indices < base_index have their final position.

    • setNextBaseToIncrement

      protected void setNextBaseToIncrement(long base_index)
      Set the next base to increment on next iteration. All base > base_index
      will be reset to their start value.

    • ConsiderAlternatives

      protected boolean ConsiderAlternatives(long base_index)
      Indicates if alternatives should be considered when iterating over base
      nodes.

    • initPosition

      protected boolean initPosition()
      Returns true if the operator needs to restart its initial position at each
      call to Start()