1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog@gmail.com>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9 
10 #ifndef EIGEN_CXX11_TENSOR_TENSOR_FORCED_EVAL_H
11 #define EIGEN_CXX11_TENSOR_TENSOR_FORCED_EVAL_H
12 
13 namespace Eigen {
14 
15 /** \class TensorForcedEval
16   * \ingroup CXX11_Tensor_Module
17   *
18   * \brief Tensor reshaping class.
19   *
20   *
21   */
22 /// template <class> class MakePointer_ is added to convert the host pointer to the device pointer.
23 /// It is added due to the fact that for our device compiler T* is not allowed.
24 /// If we wanted to use the same Evaluator functions we have to convert that type to our pointer T.
25 /// This is done through our MakePointer_ class. By default the Type in the MakePointer_<T> is T* .
26 /// Therefore, by adding the default value, we managed to convert the type and it does not break any
27 /// existing code as its default value is T*.
28 namespace internal {
29 template<typename XprType, template <class> class MakePointer_>
30 struct traits<TensorForcedEvalOp<XprType, MakePointer_> >
31 {
32   // Type promotion to handle the case where the types of the lhs and the rhs are different.
33   typedef typename XprType::Scalar Scalar;
34   typedef traits<XprType> XprTraits;
35   typedef typename traits<XprType>::StorageKind StorageKind;
36   typedef typename traits<XprType>::Index Index;
37   typedef typename XprType::Nested Nested;
38   typedef typename remove_reference<Nested>::type _Nested;
39   static const int NumDimensions = XprTraits::NumDimensions;
40   static const int Layout = XprTraits::Layout;
41 
42   enum {
43     Flags = 0
44   };
45   template <class T> struct MakePointer {
46     // Intermediate typedef to workaround MSVC issue.
47     typedef MakePointer_<T> MakePointerT;
48     typedef typename MakePointerT::Type Type;
49   };
50 };
51 
52 template<typename XprType, template <class> class MakePointer_>
53 struct eval<TensorForcedEvalOp<XprType, MakePointer_>, Eigen::Dense>
54 {
55   typedef const TensorForcedEvalOp<XprType, MakePointer_>& type;
56 };
57 
58 template<typename XprType, template <class> class MakePointer_>
59 struct nested<TensorForcedEvalOp<XprType, MakePointer_>, 1, typename eval<TensorForcedEvalOp<XprType, MakePointer_> >::type>
60 {
61   typedef TensorForcedEvalOp<XprType, MakePointer_> type;
62 };
63 
64 }  // end namespace internal
65 
66 
67 
68 template<typename XprType, template <class> class MakePointer_>
69 class TensorForcedEvalOp : public TensorBase<TensorForcedEvalOp<XprType, MakePointer_>, ReadOnlyAccessors>
70 {
71   public:
72   typedef typename Eigen::internal::traits<TensorForcedEvalOp>::Scalar Scalar;
73   typedef typename Eigen::NumTraits<Scalar>::Real RealScalar;
74   typedef typename internal::remove_const<typename XprType::CoeffReturnType>::type CoeffReturnType;
75   typedef typename Eigen::internal::nested<TensorForcedEvalOp>::type Nested;
76   typedef typename Eigen::internal::traits<TensorForcedEvalOp>::StorageKind StorageKind;
77   typedef typename Eigen::internal::traits<TensorForcedEvalOp>::Index Index;
78 
79   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorForcedEvalOp(const XprType& expr)
80       : m_xpr(expr) {}
81 
82     EIGEN_DEVICE_FUNC
83     const typename internal::remove_all<typename XprType::Nested>::type&
84     expression() const { return m_xpr; }
85 
86   protected:
87     typename XprType::Nested m_xpr;
88 };
89 
90 
91 template<typename ArgType, typename Device, template <class> class MakePointer_>
92 struct TensorEvaluator<const TensorForcedEvalOp<ArgType, MakePointer_>, Device>
93 {
94   typedef TensorForcedEvalOp<ArgType, MakePointer_> XprType;
95   typedef typename ArgType::Scalar Scalar;
96   typedef typename TensorEvaluator<ArgType, Device>::Dimensions Dimensions;
97   typedef typename XprType::Index Index;
98   typedef typename XprType::CoeffReturnType CoeffReturnType;
99   typedef typename PacketType<CoeffReturnType, Device>::type PacketReturnType;
100   static const int PacketSize = internal::unpacket_traits<PacketReturnType>::size;
101 
102   enum {
103     IsAligned = true,
104     PacketAccess = (PacketSize > 1),
105     Layout = TensorEvaluator<ArgType, Device>::Layout,
106     RawAccess = true
107   };
108 
109   EIGEN_DEVICE_FUNC TensorEvaluator(const XprType& op, const Device& device)
110 	/// op_ is used for sycl
111       : m_impl(op.expression(), device), m_op(op.expression()), m_device(device), m_buffer(NULL)
112   { }
113 
114   EIGEN_DEVICE_FUNC const Dimensions& dimensions() const { return m_impl.dimensions(); }
115 
116   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(CoeffReturnType*) {
117     const Index numValues =  internal::array_prod(m_impl.dimensions());
118     m_buffer = (CoeffReturnType*)m_device.allocate(numValues * sizeof(CoeffReturnType));
119     // Should initialize the memory in case we're dealing with non POD types.
120     if (NumTraits<CoeffReturnType>::RequireInitialization) {
121       for (Index i = 0; i < numValues; ++i) {
122         new(m_buffer+i) CoeffReturnType();
123       }
124     }
125     typedef TensorEvalToOp< const typename internal::remove_const<ArgType>::type > EvalTo;
126     EvalTo evalToTmp(m_buffer, m_op);
127     const bool PacketAccess = internal::IsVectorizable<Device, const ArgType>::value;
128     internal::TensorExecutor<const EvalTo, typename internal::remove_const<Device>::type, PacketAccess>::run(evalToTmp, m_device);
129     return true;
130   }
131   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup() {
132     m_device.deallocate(m_buffer);
133     m_buffer = NULL;
134   }
135 
136   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
137   {
138     return m_buffer[index];
139   }
140 
141   template<int LoadMode>
142   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE PacketReturnType packet(Index index) const
143   {
144     return internal::ploadt<PacketReturnType, LoadMode>(m_buffer + index);
145   }
146 
147   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorOpCost costPerCoeff(bool vectorized) const {
148     return TensorOpCost(sizeof(CoeffReturnType), 0, 0, vectorized, PacketSize);
149   }
150 
151   EIGEN_DEVICE_FUNC typename MakePointer<Scalar>::Type data() const { return m_buffer; }
152 
153   /// required by sycl in order to extract the sycl accessor
154   const TensorEvaluator<ArgType, Device>& impl() { return m_impl; }
155   /// used by sycl in order to build the sycl buffer
156   const Device& device() const{return m_device;}
157  private:
158   TensorEvaluator<ArgType, Device> m_impl;
159   const ArgType m_op;
160   const Device& m_device;
161   typename MakePointer<CoeffReturnType>::Type m_buffer;
162 };
163 
164 
165 } // end namespace Eigen
166 
167 #endif // EIGEN_CXX11_TENSOR_TENSOR_FORCED_EVAL_H
168