vtkHyperTreeGridGhostCellsGeneratorInternals.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause

#ifndef vtkHyperTreeGridGhostCellsGeneratorInternals_h
#define vtkHyperTreeGridGhostCellsGeneratorInternals_h

#include "vtkAbstractArray.h"
#include "vtkBitArray.h"
#include "vtkDataArray.h"
#include "vtkHyperTree.h"
#include "vtkHyperTreeGrid.h"
#include "vtkHyperTreeGridGhostCellsGenerator.h"
#include "vtkHyperTreeGridNonOrientedCursor.h"
#include "vtkHyperTreeGridOrientedCursor.h"
#include "vtkMultiProcessController.h"
#include "vtkSmartPointer.h"

#include <map>
#include <unordered_map>
#include <vector>

VTK_ABI_NAMESPACE_BEGIN

class vtkHyperTreeGridGhostCellsGeneratorInternals
{

public:
  vtkHyperTreeGridGhostCellsGeneratorInternals(vtkHyperTreeGridGhostCellsGenerator* self,
    vtkMultiProcessController* controller, vtkHyperTreeGrid* inputHTG, vtkHyperTreeGrid* outputHTG);

  void InitializeCellData();

  void BroadcastTreeLocations();

  void DetermineNeighbors();

  int ExchangeSizes();

  int ExchangeTreeDecomposition();

  int ExchangeCellData();

  void FinalizeCellData();

private:
  // Internal structures used for MPI message exchanges
  struct SendBuffer
  {
    SendBuffer()
      : count(0)
      , mask(0)
    {
    }
    vtkIdType count;                // len buffer
    unsigned int mask;              // ghost mask
    std::vector<vtkIdType> indices; // indices for selected cells
    vtkNew<vtkBitArray> isParent;   // decomposition amr tree
    vtkNew<vtkBitArray> isMasked;   // decomposition amr tree
  };

  struct RecvBuffer
  {
    RecvBuffer()
      : count(0)
      , offset(0)
    {
    }
    vtkIdType count;  // len buffer
    vtkIdType offset; // offset in field vector
    std::vector<vtkIdType> indices;
  };

  typedef std::map<unsigned int, SendBuffer> SendTreeBufferMap;
  typedef std::map<unsigned int, SendTreeBufferMap> SendProcessBufferMap;
  typedef std::map<unsigned int, RecvBuffer> RecvTreeBufferMap;
  typedef std::map<unsigned int, RecvTreeBufferMap> RecvProcessBufferMap;

  enum FlagType
  {
    NOT_TREATED,     // process has not been dealth with yet
    INITIALIZE_TREE, // ghost tree has been created, values not filled yet
    INITIALIZE_FIELD // cell data values have been set
  };

  // Associate the process id with its ghost tree processing state
  typedef std::unordered_map<unsigned int, FlagType> FlagMap;

  // Handling receive and send buffer.
  // The structure is as follows:
  // SendBuffer[id] or RecvBuffer[id] == process id of neighbor with whom to communicate buffer
  // SendBuffer[id][jd] or RecvBuffer[id][jd] tells which tree index is being sent.
  SendProcessBufferMap SendBuffer;
  RecvProcessBufferMap RecvBuffer;

  FlagMap Flags;

  std::vector<int> HyperTreesMapToProcesses;

public:
  // Store the values for a single cell data array, composed of two parts
  // * InternalArray is the cell array internal to this HTG (ShallowCopied)
  // * GhostCDBuffer is the buffer with values from ghost cells
  struct CellDataArray
  {
    vtkDataArray* InternalArray;
    vtkDataArray* GhostCDBuffer;
  };
  // All cell data attributes composing a vtkCellData, accessed by name.
  using CellDataAttributes = std::map<std::string, CellDataArray>;

private:
  vtkHyperTreeGridGhostCellsGenerator* Self = nullptr;
  vtkMultiProcessController* Controller = nullptr;
  vtkHyperTreeGrid* InputHTG = nullptr;
  vtkHyperTreeGrid* OutputHTG = nullptr;
  vtkSmartPointer<vtkBitArray> OutputMask;
  CellDataAttributes ImplicitCD;
  vtkIdType NumberOfVertices = 0;
  vtkIdType InitialNumberOfVertices = 0;
};

VTK_ABI_NAMESPACE_END
#endif