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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1 (at) gmail.com>
      5 // Copyright (C) 2008-2011 Gael Guennebaud <gael.guennebaud (at) inria.fr>
      6 //
      7 // This Source Code Form is subject to the terms of the Mozilla
      8 // Public License v. 2.0. If a copy of the MPL was not distributed
      9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
     10 
     11 #ifndef EIGEN_GENERAL_PRODUCT_H
     12 #define EIGEN_GENERAL_PRODUCT_H
     13 
     14 namespace Eigen {
     15 
     16 /** \class GeneralProduct
     17   * \ingroup Core_Module
     18   *
     19   * \brief Expression of the product of two general matrices or vectors
     20   *
     21   * \param LhsNested the type used to store the left-hand side
     22   * \param RhsNested the type used to store the right-hand side
     23   * \param ProductMode the type of the product
     24   *
     25   * This class represents an expression of the product of two general matrices.
     26   * We call a general matrix, a dense matrix with full storage. For instance,
     27   * This excludes triangular, selfadjoint, and sparse matrices.
     28   * It is the return type of the operator* between general matrices. Its template
     29   * arguments are determined automatically by ProductReturnType. Therefore,
     30   * GeneralProduct should never be used direclty. To determine the result type of a
     31   * function which involves a matrix product, use ProductReturnType::Type.
     32   *
     33   * \sa ProductReturnType, MatrixBase::operator*(const MatrixBase<OtherDerived>&)
     34   */
     35 template<typename Lhs, typename Rhs, int ProductType = internal::product_type<Lhs,Rhs>::value>
     36 class GeneralProduct;
     37 
     38 enum {
     39   Large = 2,
     40   Small = 3
     41 };
     42 
     43 namespace internal {
     44 
     45 template<int Rows, int Cols, int Depth> struct product_type_selector;
     46 
     47 template<int Size, int MaxSize> struct product_size_category
     48 {
     49   enum { is_large = MaxSize == Dynamic ||
     50                     Size >= EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD,
     51          value = is_large  ? Large
     52                : Size == 1 ? 1
     53                            : Small
     54   };
     55 };
     56 
     57 template<typename Lhs, typename Rhs> struct product_type
     58 {
     59   typedef typename remove_all<Lhs>::type _Lhs;
     60   typedef typename remove_all<Rhs>::type _Rhs;
     61   enum {
     62     MaxRows  = _Lhs::MaxRowsAtCompileTime,
     63     Rows  = _Lhs::RowsAtCompileTime,
     64     MaxCols  = _Rhs::MaxColsAtCompileTime,
     65     Cols  = _Rhs::ColsAtCompileTime,
     66     MaxDepth = EIGEN_SIZE_MIN_PREFER_FIXED(_Lhs::MaxColsAtCompileTime,
     67                                            _Rhs::MaxRowsAtCompileTime),
     68     Depth = EIGEN_SIZE_MIN_PREFER_FIXED(_Lhs::ColsAtCompileTime,
     69                                         _Rhs::RowsAtCompileTime),
     70     LargeThreshold = EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD
     71   };
     72 
     73   // the splitting into different lines of code here, introducing the _select enums and the typedef below,
     74   // is to work around an internal compiler error with gcc 4.1 and 4.2.
     75 private:
     76   enum {
     77     rows_select = product_size_category<Rows,MaxRows>::value,
     78     cols_select = product_size_category<Cols,MaxCols>::value,
     79     depth_select = product_size_category<Depth,MaxDepth>::value
     80   };
     81   typedef product_type_selector<rows_select, cols_select, depth_select> selector;
     82 
     83 public:
     84   enum {
     85     value = selector::ret
     86   };
     87 #ifdef EIGEN_DEBUG_PRODUCT
     88   static void debug()
     89   {
     90       EIGEN_DEBUG_VAR(Rows);
     91       EIGEN_DEBUG_VAR(Cols);
     92       EIGEN_DEBUG_VAR(Depth);
     93       EIGEN_DEBUG_VAR(rows_select);
     94       EIGEN_DEBUG_VAR(cols_select);
     95       EIGEN_DEBUG_VAR(depth_select);
     96       EIGEN_DEBUG_VAR(value);
     97   }
     98 #endif
     99 };
    100 
    101 
    102 /* The following allows to select the kind of product at compile time
    103  * based on the three dimensions of the product.
    104  * This is a compile time mapping from {1,Small,Large}^3 -> {product types} */
    105 // FIXME I'm not sure the current mapping is the ideal one.
    106 template<int M, int N>  struct product_type_selector<M,N,1>              { enum { ret = OuterProduct }; };
    107 template<int Depth>     struct product_type_selector<1,    1,    Depth>  { enum { ret = InnerProduct }; };
    108 template<>              struct product_type_selector<1,    1,    1>      { enum { ret = InnerProduct }; };
    109 template<>              struct product_type_selector<Small,1,    Small>  { enum { ret = CoeffBasedProductMode }; };
    110 template<>              struct product_type_selector<1,    Small,Small>  { enum { ret = CoeffBasedProductMode }; };
    111 template<>              struct product_type_selector<Small,Small,Small>  { enum { ret = CoeffBasedProductMode }; };
    112 template<>              struct product_type_selector<Small, Small, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
    113 template<>              struct product_type_selector<Small, Large, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
    114 template<>              struct product_type_selector<Large, Small, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
    115 template<>              struct product_type_selector<1,    Large,Small>  { enum { ret = CoeffBasedProductMode }; };
    116 template<>              struct product_type_selector<1,    Large,Large>  { enum { ret = GemvProduct }; };
    117 template<>              struct product_type_selector<1,    Small,Large>  { enum { ret = CoeffBasedProductMode }; };
    118 template<>              struct product_type_selector<Large,1,    Small>  { enum { ret = CoeffBasedProductMode }; };
    119 template<>              struct product_type_selector<Large,1,    Large>  { enum { ret = GemvProduct }; };
    120 template<>              struct product_type_selector<Small,1,    Large>  { enum { ret = CoeffBasedProductMode }; };
    121 template<>              struct product_type_selector<Small,Small,Large>  { enum { ret = GemmProduct }; };
    122 template<>              struct product_type_selector<Large,Small,Large>  { enum { ret = GemmProduct }; };
    123 template<>              struct product_type_selector<Small,Large,Large>  { enum { ret = GemmProduct }; };
    124 template<>              struct product_type_selector<Large,Large,Large>  { enum { ret = GemmProduct }; };
    125 template<>              struct product_type_selector<Large,Small,Small>  { enum { ret = GemmProduct }; };
    126 template<>              struct product_type_selector<Small,Large,Small>  { enum { ret = GemmProduct }; };
    127 template<>              struct product_type_selector<Large,Large,Small>  { enum { ret = GemmProduct }; };
    128 
    129 } // end namespace internal
    130 
    131 /** \class ProductReturnType
    132   * \ingroup Core_Module
    133   *
    134   * \brief Helper class to get the correct and optimized returned type of operator*
    135   *
    136   * \param Lhs the type of the left-hand side
    137   * \param Rhs the type of the right-hand side
    138   * \param ProductMode the type of the product (determined automatically by internal::product_mode)
    139   *
    140   * This class defines the typename Type representing the optimized product expression
    141   * between two matrix expressions. In practice, using ProductReturnType<Lhs,Rhs>::Type
    142   * is the recommended way to define the result type of a function returning an expression
    143   * which involve a matrix product. The class Product should never be
    144   * used directly.
    145   *
    146   * \sa class Product, MatrixBase::operator*(const MatrixBase<OtherDerived>&)
    147   */
    148 template<typename Lhs, typename Rhs, int ProductType>
    149 struct ProductReturnType
    150 {
    151   // TODO use the nested type to reduce instanciations ????
    152 //   typedef typename internal::nested<Lhs,Rhs::ColsAtCompileTime>::type LhsNested;
    153 //   typedef typename internal::nested<Rhs,Lhs::RowsAtCompileTime>::type RhsNested;
    154 
    155   typedef GeneralProduct<Lhs/*Nested*/, Rhs/*Nested*/, ProductType> Type;
    156 };
    157 
    158 template<typename Lhs, typename Rhs>
    159 struct ProductReturnType<Lhs,Rhs,CoeffBasedProductMode>
    160 {
    161   typedef typename internal::nested<Lhs, Rhs::ColsAtCompileTime, typename internal::plain_matrix_type<Lhs>::type >::type LhsNested;
    162   typedef typename internal::nested<Rhs, Lhs::RowsAtCompileTime, typename internal::plain_matrix_type<Rhs>::type >::type RhsNested;
    163   typedef CoeffBasedProduct<LhsNested, RhsNested, EvalBeforeAssigningBit | EvalBeforeNestingBit> Type;
    164 };
    165 
    166 template<typename Lhs, typename Rhs>
    167 struct ProductReturnType<Lhs,Rhs,LazyCoeffBasedProductMode>
    168 {
    169   typedef typename internal::nested<Lhs, Rhs::ColsAtCompileTime, typename internal::plain_matrix_type<Lhs>::type >::type LhsNested;
    170   typedef typename internal::nested<Rhs, Lhs::RowsAtCompileTime, typename internal::plain_matrix_type<Rhs>::type >::type RhsNested;
    171   typedef CoeffBasedProduct<LhsNested, RhsNested, NestByRefBit> Type;
    172 };
    173 
    174 // this is a workaround for sun CC
    175 template<typename Lhs, typename Rhs>
    176 struct LazyProductReturnType : public ProductReturnType<Lhs,Rhs,LazyCoeffBasedProductMode>
    177 {};
    178 
    179 /***********************************************************************
    180 *  Implementation of Inner Vector Vector Product
    181 ***********************************************************************/
    182 
    183 // FIXME : maybe the "inner product" could return a Scalar
    184 // instead of a 1x1 matrix ??
    185 // Pro: more natural for the user
    186 // Cons: this could be a problem if in a meta unrolled algorithm a matrix-matrix
    187 // product ends up to a row-vector times col-vector product... To tackle this use
    188 // case, we could have a specialization for Block<MatrixType,1,1> with: operator=(Scalar x);
    189 
    190 namespace internal {
    191 
    192 template<typename Lhs, typename Rhs>
    193 struct traits<GeneralProduct<Lhs,Rhs,InnerProduct> >
    194  : traits<Matrix<typename scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType,1,1> >
    195 {};
    196 
    197 }
    198 
    199 template<typename Lhs, typename Rhs>
    200 class GeneralProduct<Lhs, Rhs, InnerProduct>
    201   : internal::no_assignment_operator,
    202     public Matrix<typename internal::scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType,1,1>
    203 {
    204     typedef Matrix<typename internal::scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType,1,1> Base;
    205   public:
    206     GeneralProduct(const Lhs& lhs, const Rhs& rhs)
    207     {
    208       EIGEN_STATIC_ASSERT((internal::is_same<typename Lhs::RealScalar, typename Rhs::RealScalar>::value),
    209         YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
    210 
    211       Base::coeffRef(0,0) = (lhs.transpose().cwiseProduct(rhs)).sum();
    212     }
    213 
    214     /** Convertion to scalar */
    215     operator const typename Base::Scalar() const {
    216       return Base::coeff(0,0);
    217     }
    218 };
    219 
    220 /***********************************************************************
    221 *  Implementation of Outer Vector Vector Product
    222 ***********************************************************************/
    223 
    224 namespace internal {
    225 
    226 // Column major
    227 template<typename ProductType, typename Dest, typename Func>
    228 EIGEN_DONT_INLINE void outer_product_selector_run(const ProductType& prod, Dest& dest, const Func& func, const false_type&)
    229 {
    230   typedef typename Dest::Index Index;
    231   // FIXME make sure lhs is sequentially stored
    232   // FIXME not very good if rhs is real and lhs complex while alpha is real too
    233   const Index cols = dest.cols();
    234   for (Index j=0; j<cols; ++j)
    235     func(dest.col(j), prod.rhs().coeff(j) * prod.lhs());
    236 }
    237 
    238 // Row major
    239 template<typename ProductType, typename Dest, typename Func>
    240 EIGEN_DONT_INLINE void outer_product_selector_run(const ProductType& prod, Dest& dest, const Func& func, const true_type&) {
    241   typedef typename Dest::Index Index;
    242   // FIXME make sure rhs is sequentially stored
    243   // FIXME not very good if lhs is real and rhs complex while alpha is real too
    244   const Index rows = dest.rows();
    245   for (Index i=0; i<rows; ++i)
    246     func(dest.row(i), prod.lhs().coeff(i) * prod.rhs());
    247 }
    248 
    249 template<typename Lhs, typename Rhs>
    250 struct traits<GeneralProduct<Lhs,Rhs,OuterProduct> >
    251  : traits<ProductBase<GeneralProduct<Lhs,Rhs,OuterProduct>, Lhs, Rhs> >
    252 {};
    253 
    254 }
    255 
    256 template<typename Lhs, typename Rhs>
    257 class GeneralProduct<Lhs, Rhs, OuterProduct>
    258   : public ProductBase<GeneralProduct<Lhs,Rhs,OuterProduct>, Lhs, Rhs>
    259 {
    260     template<typename T> struct IsRowMajor : internal::conditional<(int(T::Flags)&RowMajorBit), internal::true_type, internal::false_type>::type {};
    261 
    262   public:
    263     EIGEN_PRODUCT_PUBLIC_INTERFACE(GeneralProduct)
    264 
    265     GeneralProduct(const Lhs& lhs, const Rhs& rhs) : Base(lhs,rhs)
    266     {
    267       EIGEN_STATIC_ASSERT((internal::is_same<typename Lhs::RealScalar, typename Rhs::RealScalar>::value),
    268         YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
    269     }
    270 
    271     struct set  { template<typename Dst, typename Src> void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived()  = src; } };
    272     struct add  { template<typename Dst, typename Src> void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived() += src; } };
    273     struct sub  { template<typename Dst, typename Src> void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived() -= src; } };
    274     struct adds {
    275       Scalar m_scale;
    276       adds(const Scalar& s) : m_scale(s) {}
    277       template<typename Dst, typename Src> void operator()(const Dst& dst, const Src& src) const {
    278         dst.const_cast_derived() += m_scale * src;
    279       }
    280     };
    281 
    282     template<typename Dest>
    283     inline void evalTo(Dest& dest) const {
    284       internal::outer_product_selector_run(*this, dest, set(), IsRowMajor<Dest>());
    285     }
    286 
    287     template<typename Dest>
    288     inline void addTo(Dest& dest) const {
    289       internal::outer_product_selector_run(*this, dest, add(), IsRowMajor<Dest>());
    290     }
    291 
    292     template<typename Dest>
    293     inline void subTo(Dest& dest) const {
    294       internal::outer_product_selector_run(*this, dest, sub(), IsRowMajor<Dest>());
    295     }
    296 
    297     template<typename Dest> void scaleAndAddTo(Dest& dest, const Scalar& alpha) const
    298     {
    299       internal::outer_product_selector_run(*this, dest, adds(alpha), IsRowMajor<Dest>());
    300     }
    301 };
    302 
    303 /***********************************************************************
    304 *  Implementation of General Matrix Vector Product
    305 ***********************************************************************/
    306 
    307 /*  According to the shape/flags of the matrix we have to distinghish 3 different cases:
    308  *   1 - the matrix is col-major, BLAS compatible and M is large => call fast BLAS-like colmajor routine
    309  *   2 - the matrix is row-major, BLAS compatible and N is large => call fast BLAS-like rowmajor routine
    310  *   3 - all other cases are handled using a simple loop along the outer-storage direction.
    311  *  Therefore we need a lower level meta selector.
    312  *  Furthermore, if the matrix is the rhs, then the product has to be transposed.
    313  */
    314 namespace internal {
    315 
    316 template<typename Lhs, typename Rhs>
    317 struct traits<GeneralProduct<Lhs,Rhs,GemvProduct> >
    318  : traits<ProductBase<GeneralProduct<Lhs,Rhs,GemvProduct>, Lhs, Rhs> >
    319 {};
    320 
    321 template<int Side, int StorageOrder, bool BlasCompatible>
    322 struct gemv_selector;
    323 
    324 } // end namespace internal
    325 
    326 template<typename Lhs, typename Rhs>
    327 class GeneralProduct<Lhs, Rhs, GemvProduct>
    328   : public ProductBase<GeneralProduct<Lhs,Rhs,GemvProduct>, Lhs, Rhs>
    329 {
    330   public:
    331     EIGEN_PRODUCT_PUBLIC_INTERFACE(GeneralProduct)
    332 
    333     typedef typename Lhs::Scalar LhsScalar;
    334     typedef typename Rhs::Scalar RhsScalar;
    335 
    336     GeneralProduct(const Lhs& a_lhs, const Rhs& a_rhs) : Base(a_lhs,a_rhs)
    337     {
    338 //       EIGEN_STATIC_ASSERT((internal::is_same<typename Lhs::Scalar, typename Rhs::Scalar>::value),
    339 //         YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
    340     }
    341 
    342     enum { Side = Lhs::IsVectorAtCompileTime ? OnTheLeft : OnTheRight };
    343     typedef typename internal::conditional<int(Side)==OnTheRight,_LhsNested,_RhsNested>::type MatrixType;
    344 
    345     template<typename Dest> void scaleAndAddTo(Dest& dst, const Scalar& alpha) const
    346     {
    347       eigen_assert(m_lhs.rows() == dst.rows() && m_rhs.cols() == dst.cols());
    348       internal::gemv_selector<Side,(int(MatrixType::Flags)&RowMajorBit) ? RowMajor : ColMajor,
    349                        bool(internal::blas_traits<MatrixType>::HasUsableDirectAccess)>::run(*this, dst, alpha);
    350     }
    351 };
    352 
    353 namespace internal {
    354 
    355 // The vector is on the left => transposition
    356 template<int StorageOrder, bool BlasCompatible>
    357 struct gemv_selector<OnTheLeft,StorageOrder,BlasCompatible>
    358 {
    359   template<typename ProductType, typename Dest>
    360   static void run(const ProductType& prod, Dest& dest, const typename ProductType::Scalar& alpha)
    361   {
    362     Transpose<Dest> destT(dest);
    363     enum { OtherStorageOrder = StorageOrder == RowMajor ? ColMajor : RowMajor };
    364     gemv_selector<OnTheRight,OtherStorageOrder,BlasCompatible>
    365       ::run(GeneralProduct<Transpose<const typename ProductType::_RhsNested>,Transpose<const typename ProductType::_LhsNested>, GemvProduct>
    366         (prod.rhs().transpose(), prod.lhs().transpose()), destT, alpha);
    367   }
    368 };
    369 
    370 template<typename Scalar,int Size,int MaxSize,bool Cond> struct gemv_static_vector_if;
    371 
    372 template<typename Scalar,int Size,int MaxSize>
    373 struct gemv_static_vector_if<Scalar,Size,MaxSize,false>
    374 {
    375   EIGEN_STRONG_INLINE  Scalar* data() { eigen_internal_assert(false && "should never be called"); return 0; }
    376 };
    377 
    378 template<typename Scalar,int Size>
    379 struct gemv_static_vector_if<Scalar,Size,Dynamic,true>
    380 {
    381   EIGEN_STRONG_INLINE Scalar* data() { return 0; }
    382 };
    383 
    384 template<typename Scalar,int Size,int MaxSize>
    385 struct gemv_static_vector_if<Scalar,Size,MaxSize,true>
    386 {
    387   #if EIGEN_ALIGN_STATICALLY
    388   internal::plain_array<Scalar,EIGEN_SIZE_MIN_PREFER_FIXED(Size,MaxSize),0> m_data;
    389   EIGEN_STRONG_INLINE Scalar* data() { return m_data.array; }
    390   #else
    391   // Some architectures cannot align on the stack,
    392   // => let's manually enforce alignment by allocating more data and return the address of the first aligned element.
    393   enum {
    394     ForceAlignment  = internal::packet_traits<Scalar>::Vectorizable,
    395     PacketSize      = internal::packet_traits<Scalar>::size
    396   };
    397   internal::plain_array<Scalar,EIGEN_SIZE_MIN_PREFER_FIXED(Size,MaxSize)+(ForceAlignment?PacketSize:0),0> m_data;
    398   EIGEN_STRONG_INLINE Scalar* data() {
    399     return ForceAlignment
    400             ? reinterpret_cast<Scalar*>((reinterpret_cast<size_t>(m_data.array) & ~(size_t(15))) + 16)
    401             : m_data.array;
    402   }
    403   #endif
    404 };
    405 
    406 template<> struct gemv_selector<OnTheRight,ColMajor,true>
    407 {
    408   template<typename ProductType, typename Dest>
    409   static inline void run(const ProductType& prod, Dest& dest, const typename ProductType::Scalar& alpha)
    410   {
    411     typedef typename ProductType::Index Index;
    412     typedef typename ProductType::LhsScalar   LhsScalar;
    413     typedef typename ProductType::RhsScalar   RhsScalar;
    414     typedef typename ProductType::Scalar      ResScalar;
    415     typedef typename ProductType::RealScalar  RealScalar;
    416     typedef typename ProductType::ActualLhsType ActualLhsType;
    417     typedef typename ProductType::ActualRhsType ActualRhsType;
    418     typedef typename ProductType::LhsBlasTraits LhsBlasTraits;
    419     typedef typename ProductType::RhsBlasTraits RhsBlasTraits;
    420     typedef Map<Matrix<ResScalar,Dynamic,1>, Aligned> MappedDest;
    421 
    422     ActualLhsType actualLhs = LhsBlasTraits::extract(prod.lhs());
    423     ActualRhsType actualRhs = RhsBlasTraits::extract(prod.rhs());
    424 
    425     ResScalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(prod.lhs())
    426                                   * RhsBlasTraits::extractScalarFactor(prod.rhs());
    427 
    428     enum {
    429       // FIXME find a way to allow an inner stride on the result if packet_traits<Scalar>::size==1
    430       // on, the other hand it is good for the cache to pack the vector anyways...
    431       EvalToDestAtCompileTime = Dest::InnerStrideAtCompileTime==1,
    432       ComplexByReal = (NumTraits<LhsScalar>::IsComplex) && (!NumTraits<RhsScalar>::IsComplex),
    433       MightCannotUseDest = (Dest::InnerStrideAtCompileTime!=1) || ComplexByReal
    434     };
    435 
    436     gemv_static_vector_if<ResScalar,Dest::SizeAtCompileTime,Dest::MaxSizeAtCompileTime,MightCannotUseDest> static_dest;
    437 
    438     bool alphaIsCompatible = (!ComplexByReal) || (numext::imag(actualAlpha)==RealScalar(0));
    439     bool evalToDest = EvalToDestAtCompileTime && alphaIsCompatible;
    440 
    441     RhsScalar compatibleAlpha = get_factor<ResScalar,RhsScalar>::run(actualAlpha);
    442 
    443     ei_declare_aligned_stack_constructed_variable(ResScalar,actualDestPtr,dest.size(),
    444                                                   evalToDest ? dest.data() : static_dest.data());
    445 
    446     if(!evalToDest)
    447     {
    448       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    449       int size = dest.size();
    450       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    451       #endif
    452       if(!alphaIsCompatible)
    453       {
    454         MappedDest(actualDestPtr, dest.size()).setZero();
    455         compatibleAlpha = RhsScalar(1);
    456       }
    457       else
    458         MappedDest(actualDestPtr, dest.size()) = dest;
    459     }
    460 
    461     general_matrix_vector_product
    462       <Index,LhsScalar,ColMajor,LhsBlasTraits::NeedToConjugate,RhsScalar,RhsBlasTraits::NeedToConjugate>::run(
    463         actualLhs.rows(), actualLhs.cols(),
    464         actualLhs.data(), actualLhs.outerStride(),
    465         actualRhs.data(), actualRhs.innerStride(),
    466         actualDestPtr, 1,
    467         compatibleAlpha);
    468 
    469     if (!evalToDest)
    470     {
    471       if(!alphaIsCompatible)
    472         dest += actualAlpha * MappedDest(actualDestPtr, dest.size());
    473       else
    474         dest = MappedDest(actualDestPtr, dest.size());
    475     }
    476   }
    477 };
    478 
    479 template<> struct gemv_selector<OnTheRight,RowMajor,true>
    480 {
    481   template<typename ProductType, typename Dest>
    482   static void run(const ProductType& prod, Dest& dest, const typename ProductType::Scalar& alpha)
    483   {
    484     typedef typename ProductType::LhsScalar LhsScalar;
    485     typedef typename ProductType::RhsScalar RhsScalar;
    486     typedef typename ProductType::Scalar    ResScalar;
    487     typedef typename ProductType::Index Index;
    488     typedef typename ProductType::ActualLhsType ActualLhsType;
    489     typedef typename ProductType::ActualRhsType ActualRhsType;
    490     typedef typename ProductType::_ActualRhsType _ActualRhsType;
    491     typedef typename ProductType::LhsBlasTraits LhsBlasTraits;
    492     typedef typename ProductType::RhsBlasTraits RhsBlasTraits;
    493 
    494     typename add_const<ActualLhsType>::type actualLhs = LhsBlasTraits::extract(prod.lhs());
    495     typename add_const<ActualRhsType>::type actualRhs = RhsBlasTraits::extract(prod.rhs());
    496 
    497     ResScalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(prod.lhs())
    498                                   * RhsBlasTraits::extractScalarFactor(prod.rhs());
    499 
    500     enum {
    501       // FIXME find a way to allow an inner stride on the result if packet_traits<Scalar>::size==1
    502       // on, the other hand it is good for the cache to pack the vector anyways...
    503       DirectlyUseRhs = _ActualRhsType::InnerStrideAtCompileTime==1
    504     };
    505 
    506     gemv_static_vector_if<RhsScalar,_ActualRhsType::SizeAtCompileTime,_ActualRhsType::MaxSizeAtCompileTime,!DirectlyUseRhs> static_rhs;
    507 
    508     ei_declare_aligned_stack_constructed_variable(RhsScalar,actualRhsPtr,actualRhs.size(),
    509         DirectlyUseRhs ? const_cast<RhsScalar*>(actualRhs.data()) : static_rhs.data());
    510 
    511     if(!DirectlyUseRhs)
    512     {
    513       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    514       int size = actualRhs.size();
    515       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    516       #endif
    517       Map<typename _ActualRhsType::PlainObject>(actualRhsPtr, actualRhs.size()) = actualRhs;
    518     }
    519 
    520     general_matrix_vector_product
    521       <Index,LhsScalar,RowMajor,LhsBlasTraits::NeedToConjugate,RhsScalar,RhsBlasTraits::NeedToConjugate>::run(
    522         actualLhs.rows(), actualLhs.cols(),
    523         actualLhs.data(), actualLhs.outerStride(),
    524         actualRhsPtr, 1,
    525         dest.data(), dest.innerStride(),
    526         actualAlpha);
    527   }
    528 };
    529 
    530 template<> struct gemv_selector<OnTheRight,ColMajor,false>
    531 {
    532   template<typename ProductType, typename Dest>
    533   static void run(const ProductType& prod, Dest& dest, const typename ProductType::Scalar& alpha)
    534   {
    535     typedef typename Dest::Index Index;
    536     // TODO makes sure dest is sequentially stored in memory, otherwise use a temp
    537     const Index size = prod.rhs().rows();
    538     for(Index k=0; k<size; ++k)
    539       dest += (alpha*prod.rhs().coeff(k)) * prod.lhs().col(k);
    540   }
    541 };
    542 
    543 template<> struct gemv_selector<OnTheRight,RowMajor,false>
    544 {
    545   template<typename ProductType, typename Dest>
    546   static void run(const ProductType& prod, Dest& dest, const typename ProductType::Scalar& alpha)
    547   {
    548     typedef typename Dest::Index Index;
    549     // TODO makes sure rhs is sequentially stored in memory, otherwise use a temp
    550     const Index rows = prod.rows();
    551     for(Index i=0; i<rows; ++i)
    552       dest.coeffRef(i) += alpha * (prod.lhs().row(i).cwiseProduct(prod.rhs().transpose())).sum();
    553   }
    554 };
    555 
    556 } // end namespace internal
    557 
    558 /***************************************************************************
    559 * Implementation of matrix base methods
    560 ***************************************************************************/
    561 
    562 /** \returns the matrix product of \c *this and \a other.
    563   *
    564   * \note If instead of the matrix product you want the coefficient-wise product, see Cwise::operator*().
    565   *
    566   * \sa lazyProduct(), operator*=(const MatrixBase&), Cwise::operator*()
    567   */
    568 template<typename Derived>
    569 template<typename OtherDerived>
    570 inline const typename ProductReturnType<Derived, OtherDerived>::Type
    571 MatrixBase<Derived>::operator*(const MatrixBase<OtherDerived> &other) const
    572 {
    573   // A note regarding the function declaration: In MSVC, this function will sometimes
    574   // not be inlined since DenseStorage is an unwindable object for dynamic
    575   // matrices and product types are holding a member to store the result.
    576   // Thus it does not help tagging this function with EIGEN_STRONG_INLINE.
    577   enum {
    578     ProductIsValid =  Derived::ColsAtCompileTime==Dynamic
    579                    || OtherDerived::RowsAtCompileTime==Dynamic
    580                    || int(Derived::ColsAtCompileTime)==int(OtherDerived::RowsAtCompileTime),
    581     AreVectors = Derived::IsVectorAtCompileTime && OtherDerived::IsVectorAtCompileTime,
    582     SameSizes = EIGEN_PREDICATE_SAME_MATRIX_SIZE(Derived,OtherDerived)
    583   };
    584   // note to the lost user:
    585   //    * for a dot product use: v1.dot(v2)
    586   //    * for a coeff-wise product use: v1.cwiseProduct(v2)
    587   EIGEN_STATIC_ASSERT(ProductIsValid || !(AreVectors && SameSizes),
    588     INVALID_VECTOR_VECTOR_PRODUCT__IF_YOU_WANTED_A_DOT_OR_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTIONS)
    589   EIGEN_STATIC_ASSERT(ProductIsValid || !(SameSizes && !AreVectors),
    590     INVALID_MATRIX_PRODUCT__IF_YOU_WANTED_A_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTION)
    591   EIGEN_STATIC_ASSERT(ProductIsValid || SameSizes, INVALID_MATRIX_PRODUCT)
    592 #ifdef EIGEN_DEBUG_PRODUCT
    593   internal::product_type<Derived,OtherDerived>::debug();
    594 #endif
    595   return typename ProductReturnType<Derived,OtherDerived>::Type(derived(), other.derived());
    596 }
    597 
    598 /** \returns an expression of the matrix product of \c *this and \a other without implicit evaluation.
    599   *
    600   * The returned product will behave like any other expressions: the coefficients of the product will be
    601   * computed once at a time as requested. This might be useful in some extremely rare cases when only
    602   * a small and no coherent fraction of the result's coefficients have to be computed.
    603   *
    604   * \warning This version of the matrix product can be much much slower. So use it only if you know
    605   * what you are doing and that you measured a true speed improvement.
    606   *
    607   * \sa operator*(const MatrixBase&)
    608   */
    609 template<typename Derived>
    610 template<typename OtherDerived>
    611 const typename LazyProductReturnType<Derived,OtherDerived>::Type
    612 MatrixBase<Derived>::lazyProduct(const MatrixBase<OtherDerived> &other) const
    613 {
    614   enum {
    615     ProductIsValid =  Derived::ColsAtCompileTime==Dynamic
    616                    || OtherDerived::RowsAtCompileTime==Dynamic
    617                    || int(Derived::ColsAtCompileTime)==int(OtherDerived::RowsAtCompileTime),
    618     AreVectors = Derived::IsVectorAtCompileTime && OtherDerived::IsVectorAtCompileTime,
    619     SameSizes = EIGEN_PREDICATE_SAME_MATRIX_SIZE(Derived,OtherDerived)
    620   };
    621   // note to the lost user:
    622   //    * for a dot product use: v1.dot(v2)
    623   //    * for a coeff-wise product use: v1.cwiseProduct(v2)
    624   EIGEN_STATIC_ASSERT(ProductIsValid || !(AreVectors && SameSizes),
    625     INVALID_VECTOR_VECTOR_PRODUCT__IF_YOU_WANTED_A_DOT_OR_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTIONS)
    626   EIGEN_STATIC_ASSERT(ProductIsValid || !(SameSizes && !AreVectors),
    627     INVALID_MATRIX_PRODUCT__IF_YOU_WANTED_A_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTION)
    628   EIGEN_STATIC_ASSERT(ProductIsValid || SameSizes, INVALID_MATRIX_PRODUCT)
    629 
    630   return typename LazyProductReturnType<Derived,OtherDerived>::Type(derived(), other.derived());
    631 }
    632 
    633 } // end namespace Eigen
    634 
    635 #endif // EIGEN_PRODUCT_H
    636