MeshExtrema.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.
//
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//     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
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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_meshextrema_h
#define vtk_m_worklet_contourtree_augmented_meshextrema_h
 
#include <iomanip>
 
// local includes
#include <vtkm/cont/Algorithm.h>
#include <vtkm/cont/ArrayHandleConstant.h>
#include <vtkm/cont/Invoker.h>
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/PrintVectors.h>
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/Types.h>
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/meshextrema/PointerDoubling.h>
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/meshextrema/SetStarts.h>
 
 
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/data_set_mesh/SortIndices.h>
 
namespace mesh_extrema_inc_ns = vtkm::worklet::contourtree_augmented::mesh_extrema_inc;
 
namespace vtkm
{
namespace worklet
{
namespace contourtree_augmented
{
 
class MeshExtrema
{ // MeshExtrema
public:
  vtkm::cont::Invoker Invoke;
  // arrays for peaks & pits
  IdArrayType Peaks;
  IdArrayType Pits;
  vtkm::Id NumVertices;
  vtkm::Id NumLogSteps;
 
  // constructor
  VTKM_CONT
  MeshExtrema(vtkm::Id meshSize);
 
  // routine to initialise the array before chaining
  template <class MeshType>
  void SetStarts(MeshType& mesh, bool isMaximal);
 
  // routine that computes regular chains in a merge tree
  VTKM_CONT
  void BuildRegularChains(bool isMaximal);
 
  // debug routine
  VTKM_CONT
  void DebugPrint(const char* message, const char* fileName, long lineNum);
 
}; // MeshExtrema
 
 
inline MeshExtrema::MeshExtrema(vtkm::Id meshSize)
  : Peaks()
  , Pits()
  , NumVertices(meshSize)
  , NumLogSteps(0)
{ // MeshExrema
  // Compute the number of log steps required in this pass
  NumLogSteps = 1;
  for (vtkm::Id shifter = NumVertices; shifter != 0; shifter >>= 1)
    this->NumLogSteps++;
 
  // Allocate memory for the peaks and pits
  Peaks.Allocate(NumVertices);
  Pits.Allocate(NumVertices);
  // TODO Check if we really need to set the Peaks and pits to zero or whether it is enough to allocate them
  vtkm::cont::ArrayHandleConstant<vtkm::Id> constZeroArray(0, NumVertices);
  vtkm::cont::Algorithm::Copy(constZeroArray, Peaks);
  vtkm::cont::Algorithm::Copy(constZeroArray, Pits);
} // MeshExtrema
 
 
inline void MeshExtrema::BuildRegularChains(bool isMaximal)
{ // BuildRegularChains()
  // Create vertex index array -- note, this is a fancy vtk-m array, i.e, the full array
  // is not actually allocated but the array only acts like a sequence of numbers
  vtkm::cont::ArrayHandleIndex vertexIndexArray(NumVertices);
  IdArrayType& extrema = isMaximal ? Peaks : Pits;
 
  // Create the PointerDoubling worklet and corresponding dispatcher
  vtkm::worklet::contourtree_augmented::mesh_extrema_inc::PointerDoubling pointerDoubler;
 
  // Iterate to perform pointer-doubling to build chains to extrema (i.e., maxima or minima)
  // depending on whether we are computing a JoinTree or a SplitTree
  for (vtkm::Id logStep = 0; logStep < this->NumLogSteps; logStep++)
  {
    this->Invoke(pointerDoubler,
                 vertexIndexArray, // input
                 extrema);         // output. Update whole extrema array during pointer doubling
  }
  DebugPrint("Regular Chains Built", __FILE__, __LINE__);
} // BuildRegularChains()
 
template <class MeshType>
inline void MeshExtrema::SetStarts(MeshType& mesh, bool isMaximal)
{
  mesh.SetPrepareForExecutionBehavior(isMaximal);
  mesh_extrema_inc_ns::SetStarts setStartsWorklet;
  vtkm::cont::ArrayHandleIndex sortIndexArray(mesh.NumVertices);
  if (isMaximal)
  {
    this->Invoke(setStartsWorklet,
                 sortIndexArray, // input
                 mesh,           // input
                 Peaks);         // output
  }
  else
  {
    this->Invoke(setStartsWorklet,
                 sortIndexArray, // input
                 mesh,           // input
                 Pits);          // output
  }
  DebugPrint("Regular Starts Set", __FILE__, __LINE__);
}
 
 
// debug routine
inline void MeshExtrema::DebugPrint(const char* message, const char* fileName, long lineNum)
{ // DebugPrint()
#ifdef DEBUG_PRINT
  std::cout << "---------------------------" << std::endl;
  std::cout << std::setw(30) << std::left << fileName << ":" << std::right << std::setw(4)
            << lineNum << std::endl;
  std::cout << std::left << std::string(message) << std::endl;
  std::cout << "Mesh Extrema Contain:      " << std::endl;
  std::cout << "---------------------------" << std::endl;
  std::cout << std::endl;
 
  PrintHeader(Peaks.GetNumberOfValues());
  PrintIndices("Peaks", Peaks);
  PrintIndices("Pits", Pits);
#else
  // Prevent unused parameter warning
  (void)message;
  (void)fileName;
  (void)lineNum;
#endif
} // DebugPrint()
 
 
} // namespace contourtree_augmented
} // worklet
} // vtkm
 
#endif