97 lines
2.9 KiB
C++
97 lines
2.9 KiB
C++
//
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// Created by ollie on 3/12/20.
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//
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//============================================================================
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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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#ifndef vtk_m_cont_ArrayHandlePhiloxURBG_h
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#define vtk_m_cont_ArrayHandlePhiloxURBG_h
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#include <vtkm/cont/ArrayHandleImplicit.h>
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#include <vtkm/prng/Philox.h>
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namespace vtkm
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{
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namespace cont
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{
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namespace detail
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{
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struct PhiloxFunctor
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{
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using SeedType = vtkm::Vec<vtkm::UInt32, 1>;
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PhiloxFunctor() = default;
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explicit PhiloxFunctor(SeedType seed)
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: Seed(seed)
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{
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}
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VTKM_EXEC_CONT
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vtkm::UInt64 operator()(vtkm::Id index) const
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{
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using philox_functor = vtkm::prng::philox_functor2x32x10;
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using counters_type = typename philox_functor::counters_type;
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// We deliberately use type punning to convert vtkm::Id into counters and then to
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// convert counters to vtkm::UInt64. All we need is a unique bit string as input
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// and output of the functor.
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auto idx = static_cast<vtkm::UInt64>(index);
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counters_type counters = *reinterpret_cast<counters_type*>(&idx);
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counters_type result = philox_functor{}(counters, Seed);
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return *reinterpret_cast<vtkm::UInt64*>(&result);
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}
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private:
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const SeedType Seed{};
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}; // class PhiloxFunctor
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} // namespace detail
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class VTKM_ALWAYS_EXPORT ArrayHandlePhiloxURBG
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: public vtkm::cont::ArrayHandleImplicit<detail::PhiloxFunctor>
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{
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public:
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using SeedType = vtkm::Vec<vtkm::UInt32, 1>;
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VTKM_ARRAY_HANDLE_SUBCLASS_NT(ArrayHandlePhiloxURBG,
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(vtkm::cont::ArrayHandleImplicit<detail::PhiloxFunctor>));
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explicit ArrayHandlePhiloxURBG(vtkm::Id length, SeedType seed = {})
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: Superclass(detail::PhiloxFunctor(seed), length)
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{
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}
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}; // class ArrayHandlePhiloxURBG
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/// A convenience function for creating an ArrayHandlePhiloxURBG. It takes the
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/// size of the array and generates an array holding vtkm::Id from
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/// [std::numeric_limits<vtkm::UInt64>::min, std::numeric_limits<vtkm::UInt64>::max]
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/// The type of seed is specifically designed to be an vtkm::Vec<> to provide
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/// type safety for the parameters so user will not transpose two integer parameters.
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VTKM_CONT vtkm::cont::ArrayHandlePhiloxURBG make_ArrayHandlePhiloxURBG(
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vtkm::Id length,
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vtkm::Vec<vtkm::UInt32, 1> seed = { 0 })
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{
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return vtkm::cont::ArrayHandlePhiloxURBG(length, seed);
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}
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}
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} // namespace vtkm::cont
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//=============================================================================
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// Specializations of serialization related classes
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/// @cond SERIALIZATION
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namespace vtkm
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{
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namespace cont
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{
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}
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} // namespace vtkm::cont
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#endif //vtk_m_cont_ArrayHandlePhiloxURBG_h
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