vtk-m/vtkm/worklet/contourtree_augmented/activegraph/InitializeHyperarcsFromActiveIndices.h

//============================================================================
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//
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//  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:
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// (1) Redistributions of source code must retain the above copyright notice, this
//     list of conditions and the following disclaimer.
//
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//     this list of conditions and the following disclaimer in the documentation
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// (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.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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//=============================================================================
//
//  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_augmented_active_graph_initialize_hyperarcs_from_active_indices_h
#define vtk_m_worklet_contourtree_augmented_active_graph_initialize_hyperarcs_from_active_indices_h

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


namespace vtkm
{
namespace worklet
{
namespace contourtree_augmented
{
namespace active_graph_inc
{


// Worklet for computing the sort indices from the sort order
class InitializeHyperarcsFromActiveIndices : public vtkm::worklet::WorkletMapField
{
public:
  typedef void ControlSignature(WholeArrayInOut hyperarcs,   // (input/output) hyperacrs
                                WholeArrayIn activeIndices); // (input) activeIndices
  typedef void ExecutionSignature(_1, InputIndex, _2);
  using InputDomain = _1;

  // Default Constructor
  VTKM_EXEC_CONT
  InitializeHyperarcsFromActiveIndices() {}

  template <typename InOutFieldPortalType, typename InFieldPortalType>
  VTKM_EXEC void operator()(const InOutFieldPortalType& hyperarcsPortal,
                            const vtkm::Id activeVertex,
                            const InFieldPortalType& activeIndicesPortal) const
  {
    // convert the ID from join tree indices to active graph indices
    vtkm::Id joinID = hyperarcsPortal.Get(activeVertex);
    vtkm::Id activeID = activeIndicesPortal.Get(joinID);

    // if the active ID is the same as the active vertex, it's an extremum, and should be flagged
    if (activeID == activeVertex)
      activeID |= TERMINAL_ELEMENT;

    // now write back the corrected ID
    hyperarcsPortal.Set(activeVertex, activeID);

    // In serial this worklet implements the following operation
    /*
      for (indexType activeVertex = 0; activeVertex < hyperarcs.size(); activeVertex++)
        { // per active vertex
          // convert the ID from join tree indices to active graph indices
          indexType joinID = hyperarcs[activeVertex];
          indexType activeID = activeIndices[joinID];

          // if the active ID is the same as the active vertex, it's an extremum, and should be flagged
          if (activeID == activeVertex)
                  activeID |= TERMINAL_ELEMENT;

          // now write back the corrected ID
          hyperarcs[activeVertex] = activeID;
        } // per active vertex*/
  }


}; //  InitializeHyperarcsFromActiveIndices


} // namespace active_graph_inc
} // namespace contourtree_augmented
} // namespace worklet
} // namespace vtkm

#endif