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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2015 Ke Yang <yangke@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_INFLATION_H
11 #define EIGEN_CXX11_TENSOR_TENSOR_INFLATION_H
12 
13 namespace Eigen {
14 
15 /** \class TensorInflation
16   * \ingroup CXX11_Tensor_Module
17   *
18   * \brief Tensor inflation class.
19   *
20   *
21   */
22 namespace internal {
23 template<typename Strides, typename XprType>
24 struct traits<TensorInflationOp<Strides, XprType> > : public traits<XprType>
25 {
26   typedef typename XprType::Scalar Scalar;
27   typedef traits<XprType> XprTraits;
28   typedef typename XprTraits::StorageKind StorageKind;
29   typedef typename XprTraits::Index Index;
30   typedef typename XprType::Nested Nested;
31   typedef typename remove_reference<Nested>::type _Nested;
32   static const int NumDimensions = XprTraits::NumDimensions;
33   static const int Layout = XprTraits::Layout;
34   typedef typename XprTraits::PointerType PointerType;
35 };
36 
37 template<typename Strides, typename XprType>
38 struct eval<TensorInflationOp<Strides, XprType>, Eigen::Dense>
39 {
40   typedef const TensorInflationOp<Strides, XprType>& type;
41 };
42 
43 template<typename Strides, typename XprType>
44 struct nested<TensorInflationOp<Strides, XprType>, 1, typename eval<TensorInflationOp<Strides, XprType> >::type>
45 {
46   typedef TensorInflationOp<Strides, XprType> type;
47 };
48 
49 }  // end namespace internal
50 
51 template<typename Strides, typename XprType>
52 class TensorInflationOp : public TensorBase<TensorInflationOp<Strides, XprType>, ReadOnlyAccessors>
53 {
54   public:
55   typedef typename Eigen::internal::traits<TensorInflationOp>::Scalar Scalar;
56   typedef typename Eigen::NumTraits<Scalar>::Real RealScalar;
57   typedef typename XprType::CoeffReturnType CoeffReturnType;
58   typedef typename Eigen::internal::nested<TensorInflationOp>::type Nested;
59   typedef typename Eigen::internal::traits<TensorInflationOp>::StorageKind StorageKind;
60   typedef typename Eigen::internal::traits<TensorInflationOp>::Index Index;
61 
62   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorInflationOp(const XprType& expr, const Strides& strides)
63       : m_xpr(expr), m_strides(strides) {}
64 
65     EIGEN_DEVICE_FUNC
66     const Strides& strides() const { return m_strides; }
67 
68     EIGEN_DEVICE_FUNC
69     const typename internal::remove_all<typename XprType::Nested>::type&
70     expression() const { return m_xpr; }
71 
72   protected:
73     typename XprType::Nested m_xpr;
74     const Strides m_strides;
75 };
76 
77 // Eval as rvalue
78 template<typename Strides, typename ArgType, typename Device>
79 struct TensorEvaluator<const TensorInflationOp<Strides, ArgType>, Device>
80 {
81   typedef TensorInflationOp<Strides, ArgType> XprType;
82   typedef typename XprType::Index Index;
83   static const int NumDims = internal::array_size<typename TensorEvaluator<ArgType, Device>::Dimensions>::value;
84   typedef DSizes<Index, NumDims> Dimensions;
85   typedef typename XprType::Scalar Scalar;
86   typedef typename XprType::CoeffReturnType CoeffReturnType;
87   typedef typename PacketType<CoeffReturnType, Device>::type PacketReturnType;
88   static const int PacketSize = PacketType<CoeffReturnType, Device>::size;
89   typedef StorageMemory<CoeffReturnType, Device> Storage;
90   typedef typename Storage::Type EvaluatorPointerType;
91 
92   enum {
93     IsAligned = /*TensorEvaluator<ArgType, Device>::IsAligned*/ false,
94     PacketAccess = TensorEvaluator<ArgType, Device>::PacketAccess,
95     BlockAccess = false,
96     PreferBlockAccess = false,
97     Layout = TensorEvaluator<ArgType, Device>::Layout,
98     CoordAccess = false,  // to be implemented
99     RawAccess = false
100   };
101 
102   //===- Tensor block evaluation strategy (see TensorBlock.h) -------------===//
103   typedef internal::TensorBlockNotImplemented TensorBlock;
104   //===--------------------------------------------------------------------===//
105 
106   EIGEN_STRONG_INLINE TensorEvaluator(const XprType& op, const Device& device)
107       : m_impl(op.expression(), device), m_strides(op.strides())
108   {
109     m_dimensions = m_impl.dimensions();
110     // Expand each dimension to the inflated dimension.
111     for (int i = 0; i < NumDims; ++i) {
112       m_dimensions[i] = (m_dimensions[i] - 1) * op.strides()[i] + 1;
113     }
114 
115     // Remember the strides for fast division.
116     for (int i = 0; i < NumDims; ++i) {
117       m_fastStrides[i] = internal::TensorIntDivisor<Index>(m_strides[i]);
118     }
119 
120     const typename TensorEvaluator<ArgType, Device>::Dimensions& input_dims = m_impl.dimensions();
121     if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
122       m_outputStrides[0] = 1;
123       m_inputStrides[0] = 1;
124       for (int i = 1; i < NumDims; ++i) {
125         m_outputStrides[i] = m_outputStrides[i-1] * m_dimensions[i-1];
126         m_inputStrides[i] = m_inputStrides[i-1] * input_dims[i-1];
127       }
128     } else {  // RowMajor
129       m_outputStrides[NumDims-1] = 1;
130       m_inputStrides[NumDims-1] = 1;
131       for (int i = NumDims - 2; i >= 0; --i) {
132         m_outputStrides[i] = m_outputStrides[i+1] * m_dimensions[i+1];
133         m_inputStrides[i] = m_inputStrides[i+1] * input_dims[i+1];
134       }
135     }
136   }
137 
138   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_dimensions; }
139 
140   EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(EvaluatorPointerType /*data*/) {
141     m_impl.evalSubExprsIfNeeded(NULL);
142     return true;
143   }
144   EIGEN_STRONG_INLINE void cleanup() {
145     m_impl.cleanup();
146   }
147 
148   // Computes the input index given the output index. Returns true if the output
149   // index doesn't fall into a hole.
150   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool getInputIndex(Index index, Index* inputIndex) const
151   {
152     eigen_assert(index < dimensions().TotalSize());
153     *inputIndex = 0;
154     if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
155       EIGEN_UNROLL_LOOP
156       for (int i = NumDims - 1; i > 0; --i) {
157         const Index idx = index / m_outputStrides[i];
158         if (idx != idx / m_fastStrides[i] * m_strides[i]) {
159           return false;
160         }
161         *inputIndex += idx / m_strides[i] * m_inputStrides[i];
162         index -= idx * m_outputStrides[i];
163       }
164       if (index != index / m_fastStrides[0] * m_strides[0]) {
165         return false;
166       }
167       *inputIndex += index / m_strides[0];
168       return true;
169     } else {
170       EIGEN_UNROLL_LOOP
171       for (int i = 0; i < NumDims - 1; ++i) {
172         const Index idx = index / m_outputStrides[i];
173         if (idx != idx / m_fastStrides[i] * m_strides[i]) {
174           return false;
175         }
176         *inputIndex += idx / m_strides[i] * m_inputStrides[i];
177         index -= idx * m_outputStrides[i];
178       }
179       if (index != index / m_fastStrides[NumDims-1] * m_strides[NumDims-1]) {
180         return false;
181       }
182       *inputIndex += index / m_strides[NumDims - 1];
183     }
184     return true;
185   }
186 
187   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
188   {
189     Index inputIndex = 0;
190     if (getInputIndex(index, &inputIndex)) {
191      return m_impl.coeff(inputIndex);
192     } else {
193      return Scalar(0);
194     }
195   }
196 
197   // TODO(yangke): optimize this function so that we can detect and produce
198   // all-zero packets
199   template<int LoadMode>
200   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE PacketReturnType packet(Index index) const
201   {
202     EIGEN_STATIC_ASSERT((PacketSize > 1), YOU_MADE_A_PROGRAMMING_MISTAKE)
203     eigen_assert(index+PacketSize-1 < dimensions().TotalSize());
204 
205     EIGEN_ALIGN_MAX typename internal::remove_const<CoeffReturnType>::type values[PacketSize];
206     EIGEN_UNROLL_LOOP
207     for (int i = 0; i < PacketSize; ++i) {
208       values[i] = coeff(index+i);
209     }
210     PacketReturnType rslt = internal::pload<PacketReturnType>(values);
211     return rslt;
212   }
213 
214   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorOpCost costPerCoeff(bool vectorized) const {
215     const double compute_cost = NumDims * (3 * TensorOpCost::DivCost<Index>() +
216                                            3 * TensorOpCost::MulCost<Index>() +
217                                            2 * TensorOpCost::AddCost<Index>());
218     const double input_size = m_impl.dimensions().TotalSize();
219     const double output_size = m_dimensions.TotalSize();
220     if (output_size == 0)
221       return TensorOpCost();
222     return m_impl.costPerCoeff(vectorized) +
223            TensorOpCost(sizeof(CoeffReturnType) * input_size / output_size, 0,
224                         compute_cost, vectorized, PacketSize);
225   }
226 
227   EIGEN_DEVICE_FUNC EvaluatorPointerType data() const { return NULL; }
228 
229 #ifdef EIGEN_USE_SYCL
230   // binding placeholder accessors to a command group handler for SYCL
231   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void bind(cl::sycl::handler &cgh) const {
232     m_impl.bind(cgh);
233   }
234 #endif
235 
236  protected:
237   Dimensions m_dimensions;
238   array<Index, NumDims> m_outputStrides;
239   array<Index, NumDims> m_inputStrides;
240   TensorEvaluator<ArgType, Device> m_impl;
241   const Strides m_strides;
242   array<internal::TensorIntDivisor<Index>, NumDims> m_fastStrides;
243 };
244 
245 } // end namespace Eigen
246 
247 #endif // EIGEN_CXX11_TENSOR_TENSOR_INFLATION_H
248