//============================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt 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.
//============================================================================
// Copyright (c) 2018, The Regents of the University of California, through
// Lawrence Berkeley National Laboratory (subject to receipt of any required approvals
// from the U.S. Dept. of Energy).  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// (1) Redistributions of source code must retain the above copyright notice, this
//     list of conditions and the following disclaimer.
//
// (2) Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//
// (3) Neither the name of the University of California, Lawrence Berkeley National
//     Laboratory, U.S. Dept. of Energy nor the names of its contributors may be
//     used to endorse or promote products derived from this software without
//     specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//
//=============================================================================
//
//  This code is an extension of the algorithm presented in the paper:
//  Parallel Peak Pruning for Scalable SMP Contour Tree Computation.
//  Hamish Carr, Gunther Weber, Christopher Sewell, and James Ahrens.
//  Proceedings of the IEEE Symposium on Large Data Analysis and Visualization
//  (LDAV), October 2016, Baltimore, Maryland.
//
//  The PPP2 algorithm and software were jointly developed by
//  Hamish Carr (University of Leeds), Gunther H. Weber (LBNL), and
//  Oliver Ruebel (LBNL)
//==============================================================================

#ifndef vtk_m_worklet_contourtree_distributed_bract_maker_add_terminal_flags_to_up_down_neighbours_worklet_h
#define vtk_m_worklet_contourtree_distributed_bract_maker_add_terminal_flags_to_up_down_neighbours_worklet_h

#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/Types.h>
#include <vtkm/worklet/WorkletMapField.h>

namespace vtkm
{
namespace worklet
{
namespace contourtree_distributed
{
namespace bract_maker
{

/// Step 1 of IdentifyRegularisedSupernodes
class AddTerminalFlagsToUpDownNeighboursWorklet : public vtkm::worklet::WorkletMapField
{
public:
  using ControlSignature = void(FieldIn newVertexId,        // input
                                WholeArrayOut upNeighbour,  // output
                                WholeArrayOut downNeighbour // output
  );
  using ExecutionSignature = void(InputIndex, _1, _2, _3);
  using InputDomain = _1;

  // Default Constructor
  VTKM_EXEC_CONT
  AddTerminalFlagsToUpDownNeighboursWorklet() {}

  template <typename OutFieldPortalType>
  VTKM_EXEC void operator()(const vtkm::Id& returnIndex,
                            const vtkm::Id& newVertexIdValue,
                            const OutFieldPortalType& upNeighbourPortal,
                            const OutFieldPortalType& downNeighbourPortal) const
  {
    // per vertex
    // necessary vertices
    if (!vtkm::worklet::contourtree_augmented::NoSuchElement(newVertexIdValue))
    { // necessary vertex
      // set both up & down neighbours to self with terminal element set
      upNeighbourPortal.Set(returnIndex,
                            returnIndex | vtkm::worklet::contourtree_augmented::TERMINAL_ELEMENT);
      downNeighbourPortal.Set(returnIndex,
                              returnIndex | vtkm::worklet::contourtree_augmented::TERMINAL_ELEMENT);
    } // necessary vertex

    // In serial this worklet implements the following operation
    /*
    for (indexType returnIndex = 0; returnIndex < bractVertexSuperset.size(); returnIndex++)
      { // per vertex
      // necessary vertices
      if (!noSuchElement(newVertexID[returnIndex]))
        { // necessary vertex
        // set both up & down neighbours to self with terminal element set
        upNeighbour[returnIndex] = downNeighbour[returnIndex] = returnIndex | TERMINAL_ELEMENT;
        } // necessary vertex
      } // per vertex
    */
  }
}; // AddTerminalFlagsToUpDownNeighboursWorklet


} // namespace bract_maker
} // namespace contourtree_distributed
} // namespace worklet
} // namespace vtkm

#endif
