InitializeHyperarcsFromActiveIndices.h

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