RemoveUnusedPoints.h

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//============================================================================
//  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.
//============================================================================
#ifndef vtk_m_worklet_RemoveUnusedPoints_h
#define vtk_m_worklet_RemoveUnusedPoints_h
 
#include <vtkm/cont/ArrayCopyDevice.h>
#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/cont/ArrayHandleConstant.h>
#include <vtkm/cont/ArrayHandlePermutation.h>
#include <vtkm/cont/CellSetExplicit.h>
#include <vtkm/cont/UnknownArrayHandle.h>
 
#include <vtkm/worklet/DispatcherMapField.h>
#include <vtkm/worklet/ScatterCounting.h>
#include <vtkm/worklet/WorkletMapField.h>
 
namespace vtkm
{
namespace worklet
{
 
class RemoveUnusedPoints
{
public:
  struct GeneratePointMask : public vtkm::worklet::WorkletMapField
  {
    using ControlSignature = void(FieldIn pointIndices, WholeArrayInOut pointMask);
    using ExecutionSignature = void(_1, _2);
 
    template <typename PointMaskPortalType>
    VTKM_EXEC void operator()(vtkm::Id pointIndex, const PointMaskPortalType& pointMask) const
    {
      pointMask.Set(pointIndex, 1);
    }
  };
 
  struct TransformPointIndices : public vtkm::worklet::WorkletMapField
  {
    using ControlSignature = void(FieldIn pointIndex, WholeArrayIn indexMap, FieldOut mappedPoints);
    using ExecutionSignature = _3(_1, _2);
 
    template <typename IndexMapPortalType>
    VTKM_EXEC vtkm::Id operator()(vtkm::Id pointIndex, const IndexMapPortalType& indexPortal) const
    {
      return indexPortal.Get(pointIndex);
    }
  };
 
public:
  VTKM_CONT
  RemoveUnusedPoints() = default;
 
  template <typename ShapeStorage, typename ConnectivityStorage, typename OffsetsStorage>
  VTKM_CONT explicit RemoveUnusedPoints(
    const vtkm::cont::CellSetExplicit<ShapeStorage, ConnectivityStorage, OffsetsStorage>& inCellSet)
  {
    this->FindPointsStart();
    this->FindPoints(inCellSet);
    this->FindPointsEnd();
  }
 
  VTKM_CONT void FindPointsStart() { this->MaskArray.ReleaseResources(); }
 
  template <typename ShapeStorage, typename ConnectivityStorage, typename OffsetsStorage>
  VTKM_CONT void FindPoints(
    const vtkm::cont::CellSetExplicit<ShapeStorage, ConnectivityStorage, OffsetsStorage>& inCellSet)
  {
    if (this->MaskArray.GetNumberOfValues() < 1)
    {
      // Initialize mask array to 0.
      this->MaskArray.AllocateAndFill(inCellSet.GetNumberOfPoints(), 0);
    }
    VTKM_ASSERT(this->MaskArray.GetNumberOfValues() == inCellSet.GetNumberOfPoints());
 
    vtkm::worklet::DispatcherMapField<GeneratePointMask> dispatcher;
    dispatcher.Invoke(inCellSet.GetConnectivityArray(vtkm::TopologyElementTagCell(),
                                                     vtkm::TopologyElementTagPoint()),
                      this->MaskArray);
  }
 
  VTKM_CONT void FindPointsEnd()
  {
    this->PointScatter.reset(new vtkm::worklet::ScatterCounting(this->MaskArray, true));
 
    this->MaskArray.ReleaseResources();
  }
 
  template <typename ShapeStorage, typename ConnectivityStorage, typename OffsetsStorage>
  VTKM_CONT
    vtkm::cont::CellSetExplicit<ShapeStorage, VTKM_DEFAULT_CONNECTIVITY_STORAGE_TAG, OffsetsStorage>
    MapCellSet(const vtkm::cont::CellSetExplicit<ShapeStorage, ConnectivityStorage, OffsetsStorage>&
                 inCellSet) const
  {
    VTKM_ASSERT(this->PointScatter);
 
    return MapCellSet(inCellSet,
                      this->PointScatter->GetInputToOutputMap(),
                      this->PointScatter->GetOutputToInputMap().GetNumberOfValues());
  }
 
  template <typename ShapeStorage,
            typename ConnectivityStorage,
            typename OffsetsStorage,
            typename MapStorage>
  VTKM_CONT static vtkm::cont::CellSetExplicit<ShapeStorage,
                                               VTKM_DEFAULT_CONNECTIVITY_STORAGE_TAG,
                                               OffsetsStorage>
  MapCellSet(
    const vtkm::cont::CellSetExplicit<ShapeStorage, ConnectivityStorage, OffsetsStorage>& inCellSet,
    const vtkm::cont::ArrayHandle<vtkm::Id, MapStorage>& inputToOutputPointMap,
    vtkm::Id numberOfPoints)
  {
    using VisitTopology = vtkm::TopologyElementTagCell;
    using IncidentTopology = vtkm::TopologyElementTagPoint;
 
    using NewConnectivityStorage = VTKM_DEFAULT_CONNECTIVITY_STORAGE_TAG;
 
    vtkm::cont::ArrayHandle<vtkm::Id, NewConnectivityStorage> newConnectivityArray;
 
    vtkm::worklet::DispatcherMapField<TransformPointIndices> dispatcher;
    dispatcher.Invoke(inCellSet.GetConnectivityArray(VisitTopology(), IncidentTopology()),
                      inputToOutputPointMap,
                      newConnectivityArray);
 
    vtkm::cont::CellSetExplicit<ShapeStorage, NewConnectivityStorage, OffsetsStorage> outCellSet;
    outCellSet.Fill(numberOfPoints,
                    inCellSet.GetShapesArray(VisitTopology(), IncidentTopology()),
                    newConnectivityArray,
                    inCellSet.GetOffsetsArray(VisitTopology(), IncidentTopology()));
 
    return outCellSet;
  }
 
  template <typename InArrayHandle>
  VTKM_CONT vtkm::cont::ArrayHandlePermutation<vtkm::cont::ArrayHandle<vtkm::Id>, InArrayHandle>
  MapPointFieldShallow(const InArrayHandle& inArray) const
  {
    VTKM_IS_ARRAY_HANDLE(InArrayHandle);
    VTKM_ASSERT(this->PointScatter);
 
    return vtkm::cont::make_ArrayHandlePermutation(this->PointScatter->GetOutputToInputMap(),
                                                   inArray);
  }
 
private:
  struct MapPointFieldDeepFunctor
  {
    template <typename InT, typename InS, typename OutT, typename OutS>
    VTKM_CONT void operator()(const vtkm::cont::ArrayHandle<InT, InS>& inArray,
                              vtkm::cont::ArrayHandle<OutT, OutS>& outArray,
                              const RemoveUnusedPoints& self) const
    {
      self.MapPointFieldDeep(inArray, outArray);
    }
 
    template <typename InT, typename InS>
    VTKM_CONT void operator()(const vtkm::cont::ArrayHandle<InT, InS>& inArray,
                              vtkm::cont::UnknownArrayHandle& outHolder,
                              const RemoveUnusedPoints& self) const
    {
      vtkm::cont::ArrayHandle<InT> outArray;
      (*this)(inArray, outArray, self);
      outHolder = vtkm::cont::UnknownArrayHandle{ outArray };
    }
  };
 
public:
  template <typename InT, typename InS, typename OutT, typename OutS>
  VTKM_CONT void MapPointFieldDeep(const vtkm::cont::ArrayHandle<InT, InS>& inArray,
                                   vtkm::cont::ArrayHandle<OutT, OutS>& outArray) const
  {
    vtkm::cont::ArrayCopyDevice(this->MapPointFieldShallow(inArray), outArray);
  }
 
  template <typename T, typename S>
  VTKM_CONT vtkm::cont::ArrayHandle<T> MapPointFieldDeep(
    const vtkm::cont::ArrayHandle<T, S>& inArray) const
  {
    vtkm::cont::ArrayHandle<T> outArray;
    this->MapPointFieldDeep(inArray, outArray);
 
    return outArray;
  }
 
  template <typename InValueTypes, typename InStorageTypes, typename OutArrayHandle>
  VTKM_CONT void MapPointFieldDeep(
    const vtkm::cont::UncertainArrayHandle<InValueTypes, InStorageTypes>& inArray,
    OutArrayHandle& outArray) const
  {
    vtkm::cont::CastAndCall(inArray, MapPointFieldDeepFunctor{}, outArray, *this);
  }
 
  template <typename InValueTypes, typename InStorageTypes>
  VTKM_CONT vtkm::cont::UncertainArrayHandle<InValueTypes, InStorageTypes> MapPointFieldDeep(
    const vtkm::cont::UncertainArrayHandle<InValueTypes, InStorageTypes>& inArray) const
  {
    vtkm::cont::UncertainArrayHandle<InValueTypes, InStorageTypes> outArray;
    vtkm::cont::CastAndCall(inArray, MapPointFieldDeepFunctor{}, outArray, *this);
    return outArray;
  }
 
  const vtkm::worklet::ScatterCounting& GetPointScatter() const { return *this->PointScatter; }
 
private:
  vtkm::cont::ArrayHandle<vtkm::IdComponent> MaskArray;
 
  std::shared_ptr<vtkm::worklet::ScatterCounting> PointScatter;
};
}
} // namespace vtkm::worklet
 
#endif //vtk_m_worklet_RemoveUnusedPoints_h