mirror of
https://gitlab.kitware.com/vtk/vtk-m
synced 2024-07-11 09:33:37 +00:00
5b34e6f70b
To avoid having to use a device compiler every time you wish to use `ArrayGetValue`, the actual implementation is compiled into the `vtkm_cont` library. To allow this to work for all the templated versions of `ArrayHandle`, the implementation uses the extract component features of `UnknownArrayHandle`. This works for most common arrays, but not all arrays. For arrays that cannot be directly represented by an `ArrayHandleStride`, the fallback is bad. The entire array has to be pulled to the host and then copied serially to a basic array. For `ArrayGetValue`, this is just silly. So, for arrays that cannot be simply represented by `ArrayHandleStride`, make a fallback that just uses `ReadPortal` to get the data. Often this is not the most efficient method, but it is better than the current alternative.
82 lines
3.1 KiB
C++
82 lines
3.1 KiB
C++
//============================================================================
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// Copyright (c) Kitware, Inc.
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// All rights reserved.
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// See LICENSE.txt for details.
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//
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// This software is distributed WITHOUT ANY WARRANTY; without even
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// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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// PURPOSE. See the above copyright notice for more information.
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//============================================================================
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#include <vtkm/cont/ArrayGetValues.h>
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#include <vtkm/cont/Algorithm.h>
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#include <vtkm/cont/ArrayHandlePermutation.h>
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#include <vtkm/cont/UnknownArrayHandle.h>
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#include <vtkm/List.h>
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#include <vtkm/TypeList.h>
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void vtkm::cont::internal::ArrayGetValuesImpl(const vtkm::cont::UnknownArrayHandle& ids,
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const vtkm::cont::UnknownArrayHandle& data,
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const vtkm::cont::UnknownArrayHandle& output,
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std::false_type)
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{
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auto idArray = ids.ExtractComponent<vtkm::Id>(0, vtkm::CopyFlag::On);
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output.Allocate(ids.GetNumberOfValues());
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bool copied = false;
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vtkm::ListForEach(
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[&](auto base) {
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using T = decltype(base);
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if (!copied && data.IsBaseComponentType<T>())
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{
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vtkm::IdComponent numComponents = data.GetNumberOfComponentsFlat();
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VTKM_ASSERT(output.GetNumberOfComponentsFlat() == numComponents);
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for (vtkm::IdComponent componentIdx = 0; componentIdx < numComponents; ++componentIdx)
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{
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auto dataArray = data.ExtractComponent<T>(componentIdx, vtkm::CopyFlag::On);
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auto outputArray = output.ExtractComponent<T>(componentIdx, vtkm::CopyFlag::Off);
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auto permutedArray = vtkm::cont::make_ArrayHandlePermutation(idArray, dataArray);
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bool copiedComponent = false;
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if (!dataArray.IsOnHost())
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{
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copiedComponent = vtkm::cont::TryExecute([&](auto device) {
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if (dataArray.IsOnDevice(device))
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{
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vtkm::cont::DeviceAdapterAlgorithm<decltype(device)>::Copy(permutedArray,
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outputArray);
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return true;
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}
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return false;
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});
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}
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if (!copiedComponent)
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{ // Fallback to a control-side copy if the device copy fails or if the device
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// is undefined or if the data were already on the host. In this case, the
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// best we can do is grab the portals and copy one at a time on the host with
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// a for loop.
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const vtkm::Id numVals = ids.GetNumberOfValues();
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auto inPortal = permutedArray.ReadPortal();
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auto outPortal = outputArray.WritePortal();
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for (vtkm::Id i = 0; i < numVals; ++i)
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{
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outPortal.Set(i, inPortal.Get(i));
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}
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}
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}
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copied = true;
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}
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},
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vtkm::TypeListBaseC{});
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if (!copied)
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{
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throw vtkm::cont::ErrorBadType("Unable to get values from array of type " +
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data.GetArrayTypeName());
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}
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}
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