147 lines
3.8 KiB
C++
147 lines
3.8 KiB
C++
// Copyright (c) 2010-2020, Lawrence Livermore National Security, LLC. Produced
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// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
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// LICENSE and NOTICE for details. LLNL-CODE-806117.
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//
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// This file is part of the MFEM library. For more information and source code
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// availability visit https://mfem.org.
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//
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// MFEM is free software; you can redistribute it and/or modify it under the
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// terms of the BSD-3 license. We welcome feedback and contributions, see file
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// CONTRIBUTING.md for details.
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#ifndef MFEM_DTENSOR
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#define MFEM_DTENSOR
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#include "../general/cuda.hpp"
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namespace mfem
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{
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/// A Class to compute the real index from the multi-indices of a tensor
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template <int N, int Dim, typename T, typename... Args>
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class TensorInd
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{
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public:
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MFEM_HOST_DEVICE
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static inline int result(const int* sizes, T first, Args... args)
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{
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#if !(defined(MFEM_USE_CUDA) || defined(MFEM_USE_HIP))
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MFEM_ASSERT(first<sizes[N-1],"Trying to access out of boundary.");
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#endif
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return first + sizes[N - 1] * TensorInd < N + 1, Dim, Args... >
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::result(sizes, args...);
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}
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};
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// Terminal case
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template <int Dim, typename T, typename... Args>
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class TensorInd<Dim, Dim, T, Args...>
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{
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public:
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MFEM_HOST_DEVICE
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static inline int result(const int* sizes, T first, Args... args)
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{
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#if !(defined(MFEM_USE_CUDA) || defined(MFEM_USE_HIP))
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MFEM_ASSERT(first<sizes[Dim-1],"Trying to access out of boundary.");
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#endif
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return first;
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}
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};
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/// A class to initialize the size of a Tensor
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template <int N, int Dim, typename T, typename... Args>
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class Init
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{
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public:
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static inline int result(int* sizes, T first, Args... args)
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{
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sizes[N - 1] = first;
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return first * Init < N + 1, Dim, Args... >::result(sizes, args...);
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}
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};
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// Terminal case
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template <int Dim, typename T, typename... Args>
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class Init<Dim, Dim, T, Args...>
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{
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public:
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static inline int result(int* sizes, T first, Args... args)
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{
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sizes[Dim - 1] = first;
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return first;
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}
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};
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/// A basic generic Tensor class, appropriate for use on the GPU
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template<int Dim, typename Scalar = double>
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class DeviceTensor
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{
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protected:
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int capacity;
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Scalar *data;
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int sizes[Dim];
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public:
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/// Default constructor
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DeviceTensor() = delete;
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/// Constructor to initialize a tensor from the Scalar array _data
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template <typename... Args>
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DeviceTensor(Scalar* _data, Args... args)
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{
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static_assert(sizeof...(args) == Dim, "Wrong number of arguments");
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// Initialize sizes, and compute the number of values
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const long int nb = Init<1, Dim, Args...>::result(sizes, args...);
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capacity = nb;
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data = (capacity > 0) ? _data : NULL;
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}
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/// Copy constructor
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MFEM_HOST_DEVICE DeviceTensor(const DeviceTensor& t)
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{
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capacity = t.capacity;
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for (int i = 0; i < Dim; ++i)
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{
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sizes[i] = t.sizes[i];
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}
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data = t.data;
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}
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/// Conversion to `Scalar *`.
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inline operator Scalar *() const { return data; }
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/// Const accessor for the data
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template <typename... Args> MFEM_HOST_DEVICE inline
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Scalar& operator()(Args... args) const
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{
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static_assert(sizeof...(args) == Dim, "Wrong number of arguments");
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return data[ TensorInd<1, Dim, Args...>::result(sizes, args...) ];
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}
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/// Subscript operator where the tensor is viewed as a 1D array.
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MFEM_HOST_DEVICE inline Scalar& operator[](int i) const
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{
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return data[i];
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}
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};
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/** @brief Wrap a pointer as a DeviceTensor with automatically deduced template
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parameters */
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template <typename T, typename... Dims>
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inline DeviceTensor<sizeof...(Dims),T> Reshape(T *ptr, Dims... dims)
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{
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return DeviceTensor<sizeof...(Dims),T>(ptr, dims...);
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}
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typedef DeviceTensor<1,int> DeviceArray;
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typedef DeviceTensor<1,double> DeviceVector;
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typedef DeviceTensor<2,double> DeviceMatrix;
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} // mfem namespace
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#endif // MFEM_DTENSOR
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