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      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 (at) 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_CONCATENATION_H
     11 #define EIGEN_CXX11_TENSOR_TENSOR_CONCATENATION_H
     12 
     13 namespace Eigen {
     14 
     15 /** \class TensorConcatenationOp
     16   * \ingroup CXX11_Tensor_Module
     17   *
     18   * \brief Tensor concatenation class.
     19   *
     20   *
     21   */
     22 namespace internal {
     23 template<typename Axis, typename LhsXprType, typename RhsXprType>
     24 struct traits<TensorConcatenationOp<Axis, LhsXprType, RhsXprType> >
     25 {
     26   // Type promotion to handle the case where the types of the lhs and the rhs are different.
     27   typedef typename promote_storage_type<typename LhsXprType::Scalar,
     28                                         typename RhsXprType::Scalar>::ret Scalar;
     29   typedef typename promote_storage_type<typename traits<LhsXprType>::StorageKind,
     30                                         typename traits<RhsXprType>::StorageKind>::ret StorageKind;
     31   typedef typename promote_index_type<typename traits<LhsXprType>::Index,
     32                                       typename traits<RhsXprType>::Index>::type Index;
     33   typedef typename LhsXprType::Nested LhsNested;
     34   typedef typename RhsXprType::Nested RhsNested;
     35   typedef typename remove_reference<LhsNested>::type _LhsNested;
     36   typedef typename remove_reference<RhsNested>::type _RhsNested;
     37   static const int NumDimensions = traits<LhsXprType>::NumDimensions;
     38   static const int Layout = traits<LhsXprType>::Layout;
     39   enum { Flags = 0 };
     40 };
     41 
     42 template<typename Axis, typename LhsXprType, typename RhsXprType>
     43 struct eval<TensorConcatenationOp<Axis, LhsXprType, RhsXprType>, Eigen::Dense>
     44 {
     45   typedef const TensorConcatenationOp<Axis, LhsXprType, RhsXprType>& type;
     46 };
     47 
     48 template<typename Axis, typename LhsXprType, typename RhsXprType>
     49 struct nested<TensorConcatenationOp<Axis, LhsXprType, RhsXprType>, 1, typename eval<TensorConcatenationOp<Axis, LhsXprType, RhsXprType> >::type>
     50 {
     51   typedef TensorConcatenationOp<Axis, LhsXprType, RhsXprType> type;
     52 };
     53 
     54 }  // end namespace internal
     55 
     56 
     57 template<typename Axis, typename LhsXprType, typename RhsXprType>
     58 class TensorConcatenationOp : public TensorBase<TensorConcatenationOp<Axis, LhsXprType, RhsXprType>, WriteAccessors>
     59 {
     60   public:
     61     typedef typename internal::traits<TensorConcatenationOp>::Scalar Scalar;
     62     typedef typename internal::traits<TensorConcatenationOp>::StorageKind StorageKind;
     63     typedef typename internal::traits<TensorConcatenationOp>::Index Index;
     64     typedef typename internal::nested<TensorConcatenationOp>::type Nested;
     65     typedef typename internal::promote_storage_type<typename LhsXprType::CoeffReturnType,
     66                                                     typename RhsXprType::CoeffReturnType>::ret CoeffReturnType;
     67     typedef typename NumTraits<Scalar>::Real RealScalar;
     68 
     69     EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorConcatenationOp(const LhsXprType& lhs, const RhsXprType& rhs, Axis axis)
     70         : m_lhs_xpr(lhs), m_rhs_xpr(rhs), m_axis(axis) {}
     71 
     72     EIGEN_DEVICE_FUNC
     73     const typename internal::remove_all<typename LhsXprType::Nested>::type&
     74     lhsExpression() const { return m_lhs_xpr; }
     75 
     76     EIGEN_DEVICE_FUNC
     77     const typename internal::remove_all<typename RhsXprType::Nested>::type&
     78     rhsExpression() const { return m_rhs_xpr; }
     79 
     80     EIGEN_DEVICE_FUNC const Axis& axis() const { return m_axis; }
     81 
     82     EIGEN_DEVICE_FUNC
     83     EIGEN_STRONG_INLINE TensorConcatenationOp& operator = (const TensorConcatenationOp& other)
     84     {
     85       typedef TensorAssignOp<TensorConcatenationOp, const TensorConcatenationOp> Assign;
     86       Assign assign(*this, other);
     87       internal::TensorExecutor<const Assign, DefaultDevice>::run(assign, DefaultDevice());
     88       return *this;
     89     }
     90 
     91     template<typename OtherDerived>
     92     EIGEN_DEVICE_FUNC
     93     EIGEN_STRONG_INLINE TensorConcatenationOp& operator = (const OtherDerived& other)
     94     {
     95       typedef TensorAssignOp<TensorConcatenationOp, const OtherDerived> Assign;
     96       Assign assign(*this, other);
     97       internal::TensorExecutor<const Assign, DefaultDevice>::run(assign, DefaultDevice());
     98       return *this;
     99     }
    100 
    101   protected:
    102     typename LhsXprType::Nested m_lhs_xpr;
    103     typename RhsXprType::Nested m_rhs_xpr;
    104     const Axis m_axis;
    105 };
    106 
    107 
    108 // Eval as rvalue
    109 template<typename Axis, typename LeftArgType, typename RightArgType, typename Device>
    110 struct TensorEvaluator<const TensorConcatenationOp<Axis, LeftArgType, RightArgType>, Device>
    111 {
    112   typedef TensorConcatenationOp<Axis, LeftArgType, RightArgType> XprType;
    113   typedef typename XprType::Index Index;
    114   static const int NumDims = internal::array_size<typename TensorEvaluator<LeftArgType, Device>::Dimensions>::value;
    115   static const int RightNumDims = internal::array_size<typename TensorEvaluator<RightArgType, Device>::Dimensions>::value;
    116   typedef DSizes<Index, NumDims> Dimensions;
    117   typedef typename XprType::Scalar Scalar;
    118   typedef typename XprType::CoeffReturnType CoeffReturnType;
    119   typedef typename PacketType<CoeffReturnType, Device>::type PacketReturnType;
    120   enum {
    121     IsAligned = false,
    122     PacketAccess = TensorEvaluator<LeftArgType, Device>::PacketAccess & TensorEvaluator<RightArgType, Device>::PacketAccess,
    123     Layout = TensorEvaluator<LeftArgType, Device>::Layout,
    124     RawAccess = false
    125   };
    126 
    127   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorEvaluator(const XprType& op, const Device& device)
    128     : m_leftImpl(op.lhsExpression(), device), m_rightImpl(op.rhsExpression(), device), m_axis(op.axis())
    129   {
    130     EIGEN_STATIC_ASSERT((static_cast<int>(TensorEvaluator<LeftArgType, Device>::Layout) == static_cast<int>(TensorEvaluator<RightArgType, Device>::Layout) || NumDims == 1), YOU_MADE_A_PROGRAMMING_MISTAKE);
    131     EIGEN_STATIC_ASSERT((NumDims == RightNumDims), YOU_MADE_A_PROGRAMMING_MISTAKE);
    132     EIGEN_STATIC_ASSERT((NumDims > 0), YOU_MADE_A_PROGRAMMING_MISTAKE);
    133 
    134     eigen_assert(0 <= m_axis && m_axis < NumDims);
    135     const Dimensions& lhs_dims = m_leftImpl.dimensions();
    136     const Dimensions& rhs_dims = m_rightImpl.dimensions();
    137     {
    138       int i = 0;
    139       for (; i < m_axis; ++i) {
    140         eigen_assert(lhs_dims[i] > 0);
    141         eigen_assert(lhs_dims[i] == rhs_dims[i]);
    142         m_dimensions[i] = lhs_dims[i];
    143       }
    144       eigen_assert(lhs_dims[i] > 0);  // Now i == m_axis.
    145       eigen_assert(rhs_dims[i] > 0);
    146       m_dimensions[i] = lhs_dims[i] + rhs_dims[i];
    147       for (++i; i < NumDims; ++i) {
    148         eigen_assert(lhs_dims[i] > 0);
    149         eigen_assert(lhs_dims[i] == rhs_dims[i]);
    150         m_dimensions[i] = lhs_dims[i];
    151       }
    152     }
    153 
    154     if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
    155       m_leftStrides[0] = 1;
    156       m_rightStrides[0] = 1;
    157       m_outputStrides[0] = 1;
    158 
    159       for (int j = 1; j < NumDims; ++j) {
    160         m_leftStrides[j] = m_leftStrides[j-1] * lhs_dims[j-1];
    161         m_rightStrides[j] = m_rightStrides[j-1] * rhs_dims[j-1];
    162         m_outputStrides[j] = m_outputStrides[j-1] * m_dimensions[j-1];
    163       }
    164     } else {
    165       m_leftStrides[NumDims - 1] = 1;
    166       m_rightStrides[NumDims - 1] = 1;
    167       m_outputStrides[NumDims - 1] = 1;
    168 
    169       for (int j = NumDims - 2; j >= 0; --j) {
    170         m_leftStrides[j] = m_leftStrides[j+1] * lhs_dims[j+1];
    171         m_rightStrides[j] = m_rightStrides[j+1] * rhs_dims[j+1];
    172         m_outputStrides[j] = m_outputStrides[j+1] * m_dimensions[j+1];
    173       }
    174     }
    175   }
    176 
    177   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_dimensions; }
    178 
    179   // TODO(phli): Add short-circuit memcpy evaluation if underlying data are linear?
    180   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(Scalar* /*data*/)
    181   {
    182     m_leftImpl.evalSubExprsIfNeeded(NULL);
    183     m_rightImpl.evalSubExprsIfNeeded(NULL);
    184     return true;
    185   }
    186 
    187   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup()
    188   {
    189     m_leftImpl.cleanup();
    190     m_rightImpl.cleanup();
    191   }
    192 
    193   // TODO(phli): attempt to speed this up. The integer divisions and modulo are slow.
    194   // See CL/76180724 comments for more ideas.
    195   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType coeff(Index index) const
    196   {
    197     // Collect dimension-wise indices (subs).
    198     array<Index, NumDims> subs;
    199     if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
    200       for (int i = NumDims - 1; i > 0; --i) {
    201         subs[i] = index / m_outputStrides[i];
    202         index -= subs[i] * m_outputStrides[i];
    203       }
    204       subs[0] = index;
    205     } else {
    206       for (int i = 0; i < NumDims - 1; ++i) {
    207         subs[i] = index / m_outputStrides[i];
    208         index -= subs[i] * m_outputStrides[i];
    209       }
    210       subs[NumDims - 1] = index;
    211     }
    212 
    213     const Dimensions& left_dims = m_leftImpl.dimensions();
    214     if (subs[m_axis] < left_dims[m_axis]) {
    215       Index left_index;
    216       if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
    217         left_index = subs[0];
    218         for (int i = 1; i < NumDims; ++i) {
    219           left_index += (subs[i] % left_dims[i]) * m_leftStrides[i];
    220         }
    221       } else {
    222         left_index = subs[NumDims - 1];
    223         for (int i = NumDims - 2; i >= 0; --i) {
    224           left_index += (subs[i] % left_dims[i]) * m_leftStrides[i];
    225         }
    226       }
    227       return m_leftImpl.coeff(left_index);
    228     } else {
    229       subs[m_axis] -= left_dims[m_axis];
    230       const Dimensions& right_dims = m_rightImpl.dimensions();
    231       Index right_index;
    232       if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
    233         right_index = subs[0];
    234         for (int i = 1; i < NumDims; ++i) {
    235           right_index += (subs[i] % right_dims[i]) * m_rightStrides[i];
    236         }
    237       } else {
    238         right_index = subs[NumDims - 1];
    239         for (int i = NumDims - 2; i >= 0; --i) {
    240           right_index += (subs[i] % right_dims[i]) * m_rightStrides[i];
    241         }
    242       }
    243       return m_rightImpl.coeff(right_index);
    244     }
    245   }
    246 
    247   // TODO(phli): Add a real vectorization.
    248   template<int LoadMode>
    249   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE PacketReturnType packet(Index index) const
    250   {
    251     const int packetSize = internal::unpacket_traits<PacketReturnType>::size;
    252     EIGEN_STATIC_ASSERT((packetSize > 1), YOU_MADE_A_PROGRAMMING_MISTAKE)
    253     eigen_assert(index + packetSize - 1 < dimensions().TotalSize());
    254 
    255     EIGEN_ALIGN_MAX CoeffReturnType values[packetSize];
    256     for (int i = 0; i < packetSize; ++i) {
    257       values[i] = coeff(index+i);
    258     }
    259     PacketReturnType rslt = internal::pload<PacketReturnType>(values);
    260     return rslt;
    261   }
    262 
    263   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorOpCost
    264   costPerCoeff(bool vectorized) const {
    265     const double compute_cost = NumDims * (2 * TensorOpCost::AddCost<Index>() +
    266                                            2 * TensorOpCost::MulCost<Index>() +
    267                                            TensorOpCost::DivCost<Index>() +
    268                                            TensorOpCost::ModCost<Index>());
    269     const double lhs_size = m_leftImpl.dimensions().TotalSize();
    270     const double rhs_size = m_rightImpl.dimensions().TotalSize();
    271     return (lhs_size / (lhs_size + rhs_size)) *
    272                m_leftImpl.costPerCoeff(vectorized) +
    273            (rhs_size / (lhs_size + rhs_size)) *
    274                m_rightImpl.costPerCoeff(vectorized) +
    275            TensorOpCost(0, 0, compute_cost);
    276   }
    277 
    278   EIGEN_DEVICE_FUNC Scalar* data() const { return NULL; }
    279 
    280   protected:
    281     Dimensions m_dimensions;
    282     array<Index, NumDims> m_outputStrides;
    283     array<Index, NumDims> m_leftStrides;
    284     array<Index, NumDims> m_rightStrides;
    285     TensorEvaluator<LeftArgType, Device> m_leftImpl;
    286     TensorEvaluator<RightArgType, Device> m_rightImpl;
    287     const Axis m_axis;
    288 };
    289 
    290 // Eval as lvalue
    291 template<typename Axis, typename LeftArgType, typename RightArgType, typename Device>
    292   struct TensorEvaluator<TensorConcatenationOp<Axis, LeftArgType, RightArgType>, Device>
    293   : public TensorEvaluator<const TensorConcatenationOp<Axis, LeftArgType, RightArgType>, Device>
    294 {
    295   typedef TensorEvaluator<const TensorConcatenationOp<Axis, LeftArgType, RightArgType>, Device> Base;
    296   typedef TensorConcatenationOp<Axis, LeftArgType, RightArgType> XprType;
    297   typedef typename Base::Dimensions Dimensions;
    298   enum {
    299     IsAligned = false,
    300     PacketAccess = TensorEvaluator<LeftArgType, Device>::PacketAccess & TensorEvaluator<RightArgType, Device>::PacketAccess,
    301     Layout = TensorEvaluator<LeftArgType, Device>::Layout,
    302     RawAccess = false
    303   };
    304 
    305   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorEvaluator(XprType& op, const Device& device)
    306     : Base(op, device)
    307   {
    308     EIGEN_STATIC_ASSERT((static_cast<int>(Layout) == static_cast<int>(ColMajor)), YOU_MADE_A_PROGRAMMING_MISTAKE);
    309   }
    310 
    311   typedef typename XprType::Index Index;
    312   typedef typename XprType::Scalar Scalar;
    313   typedef typename XprType::CoeffReturnType CoeffReturnType;
    314   typedef typename PacketType<CoeffReturnType, Device>::type PacketReturnType;
    315 
    316   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CoeffReturnType& coeffRef(Index index)
    317   {
    318     // Collect dimension-wise indices (subs).
    319     array<Index, Base::NumDims> subs;
    320     for (int i = Base::NumDims - 1; i > 0; --i) {
    321       subs[i] = index / this->m_outputStrides[i];
    322       index -= subs[i] * this->m_outputStrides[i];
    323     }
    324     subs[0] = index;
    325 
    326     const Dimensions& left_dims = this->m_leftImpl.dimensions();
    327     if (subs[this->m_axis] < left_dims[this->m_axis]) {
    328       Index left_index = subs[0];
    329       for (int i = 1; i < Base::NumDims; ++i) {
    330         left_index += (subs[i] % left_dims[i]) * this->m_leftStrides[i];
    331       }
    332       return this->m_leftImpl.coeffRef(left_index);
    333     } else {
    334       subs[this->m_axis] -= left_dims[this->m_axis];
    335       const Dimensions& right_dims = this->m_rightImpl.dimensions();
    336       Index right_index = subs[0];
    337       for (int i = 1; i < Base::NumDims; ++i) {
    338         right_index += (subs[i] % right_dims[i]) * this->m_rightStrides[i];
    339       }
    340       return this->m_rightImpl.coeffRef(right_index);
    341     }
    342   }
    343 
    344   template <int StoreMode> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    345   void writePacket(Index index, const PacketReturnType& x)
    346   {
    347     const int packetSize = internal::unpacket_traits<PacketReturnType>::size;
    348     EIGEN_STATIC_ASSERT((packetSize > 1), YOU_MADE_A_PROGRAMMING_MISTAKE)
    349     eigen_assert(index + packetSize - 1 < this->dimensions().TotalSize());
    350 
    351     EIGEN_ALIGN_MAX CoeffReturnType values[packetSize];
    352     internal::pstore<CoeffReturnType, PacketReturnType>(values, x);
    353     for (int i = 0; i < packetSize; ++i) {
    354       coeffRef(index+i) = values[i];
    355     }
    356   }
    357 };
    358 
    359 } // end namespace Eigen
    360 
    361 #endif // EIGEN_CXX11_TENSOR_TENSOR_CONCATENATION_H
    362