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  Program:   ParaView
  Module:    $RCSfile$

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkInSituPParticlePathFilter - An In Situ Particle tracer for unsteady vector fields
// .SECTION Description
// vtkInSituPParticlePathFilter is a filter that integrates a vector field
// to generate particle paths. It is intended for in situ use. The additions
// to the parallel particle path filter is that the particle locations
// at previous time steps can be cleared out (ClearCache data member)
// and restarted connection can be used to continue advecting particles
// from a restarted simulation.
// .SECTION See Also
// vtkPParticlePathFilterBase has the details of the algorithms

#ifndef vtkInSituPParticlePathFilter_h
#define vtkInSituPParticlePathFilter_h

#include "vtkPParticlePathFilter.h"
#include "vtkPVVTKExtensionsDefaultModule.h" //needed for exports

class VTKPVVTKEXTENSIONSDEFAULT_EXPORT vtkInSituPParticlePathFilter: public vtkPParticlePathFilter
{
public:
  vtkTypeMacro(vtkInSituPParticlePathFilter,vtkPParticlePathFilter)
  void PrintSelf(ostream& os, vtkIndent indent);

  static vtkInSituPParticlePathFilter *New();

  // Description:
  // Set whether or not to clear out cache of previous time steps.
  // Default value is false. Clearing the cache is aimed towards in situ use.
  void SetClearCache(bool);

  // Description:
  // Provide support pre-pending previously computed particle paths.
  void AddRestartConnection(vtkAlgorithmOutput* input);
  void RemoveAllRestarts();

  // Description:
  // Set/Get if the simulation has been restarted. If it is a restarted
  // simulation we may not necessarily want to inject/reinject particles
  // on the first time step. The default is False.
  vtkSetMacro(RestartedSimulation, bool);
  vtkGetMacro(RestartedSimulation, bool);

  // Description:
  // Specify the first time step that particle paths are computed.
  // This is useful for restarted simulations or when the simulation's
  // first time step isn't 0. The default is 0.
  vtkSetMacro(FirstTimeStep, int);
  vtkGetMacro(FirstTimeStep, int);

protected:
  vtkInSituPParticlePathFilter();
  ~vtkInSituPParticlePathFilter();

  // Description:
  // Overriding this method allows us to inject the seeds as some
  // point other than the first time step. This is needed for
  // restarted simulations where the restart step may not
  // coincide with an injection step. Even if it did, the seeds
  // probably were already reinjected before the restart files
  // were written.
  virtual std::vector<vtkDataSet*> GetSeedSources(vtkInformationVector* inputVector, int timeStep);

  // Description:
  // We add in a third, optional port for adding in particles for a
  // restarted simulation. These particles are only added at the first
  // time step.
  virtual int FillInputPortInformation(int port, vtkInformation *info);

  int RequestUpdateExtent(vtkInformation* request, vtkInformationVector** inputVector,
                          vtkInformationVector* outputVector);

  // Description:
  // For restarts of particle paths, we add in the ability to add in
  // particles from a previous computation that we will still advect.
  virtual void AddRestartSeeds(vtkInformationVector**);

  // Description:
  // Before starting the particle trace, classify
  // all the injection/seed points according to which processor
  // they belong to. This saves us retesting at every injection time
  // providing 1) The volumes are static, 2) the seed points are static
  // If either are non static, then this step is skipped.
  // This takes into account that the "seeds" may just be restarted
  // particles.
  virtual void AssignSeedsToProcessors(
    double time, vtkDataSet *source, int sourceID, int ptId,
    vtkParticleTracerBaseNamespace::ParticleVector &localSeedPoints,
    int &localAssignedCount);

private:
  vtkInSituPParticlePathFilter(const vtkInSituPParticlePathFilter&) VTK_DELETE_FUNCTION;
  void operator=(const vtkInSituPParticlePathFilter&) VTK_DELETE_FUNCTION;

  // Description:
  // For restart input we need to mark that we will use arrays to
  // create new particles so that we can get proper history information
  // from them.
  bool UseArrays;

  // Description:
  // Specify whether or not the particle paths are computed for a
  // restarted simulation. The default is False indicating this
  // is not a restarted simulation.
  bool RestartedSimulation;

  // Description:
  // Specify the first simulation time step that particles are computed.
  // This is useful for restarted simulations as well as simulations or
  // particle path tracking that don't start at time step 0. This is
  // used in computing the time step age and injected step id in
  // the output.
  int FirstTimeStep;
};
#endif
