vtk-m/vtkm/worklet/CellAverage.h
Allison Vacanti 5db762ee71 Refactor topology mappings to clarify meaning.
The `From` and `To` nomenclature for topology mapping has been confusing for
both users and developers, especially at lower levels where the intention of
mapping attributes from one element to another is easily conflated with the
concept of mapping indices (which maps in the exact opposite direction).

These identifiers have been renamed to `VisitTopology` and `IncidentTopology`
to clarify the direction of the mapping. The order in which these template
parameters are specified for `WorkletMapTopology` have also been reversed,
since eventually there may be more than one `IncidentTopology`, and having
`IncidentTopology` at the end will allow us to replace it with a variadic
template parameter pack in the future.

Other implementation details supporting these worklets, include `Fetch` tags,
`Connectivity` classes, and methods on the various `CellSet` classes (such as
`PrepareForInput` have also reversed their template arguments. These will need
to be cautiously updated.

The convenience implementations of `WorkletMapTopology` have been renamed for
clarity as follows:

```
WorkletMapPointToCell --> WorkletVisitCellsWithPoints
WorkletMapCellToPoint --> WorkletVisitPointsWithCells
```

The `ControlSignature` tags have been renamed as follows:

```
FieldInTo --> FieldInVisit
FieldInFrom --> FieldInMap
FromCount --> IncidentElementCount
FromIndices --> IncidentElementIndices
```
2019-08-06 11:27:26 -04:00

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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_CellAverage_h
#define vtk_m_worklet_CellAverage_h
#include <vtkm/worklet/WorkletMapTopology.h>
#include <vtkm/VecTraits.h>
namespace vtkm
{
namespace worklet
{
//simple functor that returns the average point value as a cell field
class CellAverage : public vtkm::worklet::WorkletVisitCellsWithPoints
{
public:
using ControlSignature = void(CellSetIn cellset, FieldInPoint inPoints, FieldOutCell outCells);
using ExecutionSignature = void(PointCount, _2, _3);
using InputDomain = _1;
template <typename PointValueVecType, typename OutType>
VTKM_EXEC void operator()(const vtkm::IdComponent& numPoints,
const PointValueVecType& pointValues,
OutType& average) const
{
using PointValueType = typename PointValueVecType::ComponentType;
using InVecSize =
std::integral_constant<vtkm::IdComponent, vtkm::VecTraits<PointValueType>::NUM_COMPONENTS>;
using OutVecSize =
std::integral_constant<vtkm::IdComponent, vtkm::VecTraits<OutType>::NUM_COMPONENTS>;
using SameLengthVectors = typename std::is_same<InVecSize, OutVecSize>::type;
this->DoAverage(numPoints, pointValues, average, SameLengthVectors());
}
private:
template <typename PointValueVecType, typename OutType>
VTKM_EXEC void DoAverage(const vtkm::IdComponent& numPoints,
const PointValueVecType& pointValues,
OutType& average,
std::true_type) const
{
using OutComponentType = typename vtkm::VecTraits<OutType>::ComponentType;
OutType sum = OutType(pointValues[0]);
for (vtkm::IdComponent pointIndex = 1; pointIndex < numPoints; ++pointIndex)
{
// OutType constructor is for when OutType is a Vec.
// static_cast is for when OutType is a small int that gets promoted to int32.
sum = static_cast<OutType>(sum + OutType(pointValues[pointIndex]));
}
// OutType constructor is for when OutType is a Vec.
// static_cast is for when OutType is a small int that gets promoted to int32.
average = static_cast<OutType>(sum / OutType(static_cast<OutComponentType>(numPoints)));
}
template <typename PointValueVecType, typename OutType>
VTKM_EXEC void DoAverage(const vtkm::IdComponent& vtkmNotUsed(numPoints),
const PointValueVecType& vtkmNotUsed(pointValues),
OutType& vtkmNotUsed(average),
std::false_type) const
{
this->RaiseError("CellAverage called with mismatched Vec sizes for CellAverage.");
}
};
}
} // namespace vtkm::worklet
#endif // vtk_m_worklet_CellAverage_h