Home | History | Annotate | Download | only in Core
      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 enum {
     17   Large = 2,
     18   Small = 3
     19 };
     20 
     21 namespace internal {
     22 
     23 template<int Rows, int Cols, int Depth> struct product_type_selector;
     24 
     25 template<int Size, int MaxSize> struct product_size_category
     26 {
     27   enum { is_large = MaxSize == Dynamic ||
     28                     Size >= EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD ||
     29                     (Size==Dynamic && MaxSize>=EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD),
     30          value = is_large  ? Large
     31                : Size == 1 ? 1
     32                            : Small
     33   };
     34 };
     35 
     36 template<typename Lhs, typename Rhs> struct product_type
     37 {
     38   typedef typename remove_all<Lhs>::type _Lhs;
     39   typedef typename remove_all<Rhs>::type _Rhs;
     40   enum {
     41     MaxRows = traits<_Lhs>::MaxRowsAtCompileTime,
     42     Rows    = traits<_Lhs>::RowsAtCompileTime,
     43     MaxCols = traits<_Rhs>::MaxColsAtCompileTime,
     44     Cols    = traits<_Rhs>::ColsAtCompileTime,
     45     MaxDepth = EIGEN_SIZE_MIN_PREFER_FIXED(traits<_Lhs>::MaxColsAtCompileTime,
     46                                            traits<_Rhs>::MaxRowsAtCompileTime),
     47     Depth = EIGEN_SIZE_MIN_PREFER_FIXED(traits<_Lhs>::ColsAtCompileTime,
     48                                         traits<_Rhs>::RowsAtCompileTime)
     49   };
     50 
     51   // the splitting into different lines of code here, introducing the _select enums and the typedef below,
     52   // is to work around an internal compiler error with gcc 4.1 and 4.2.
     53 private:
     54   enum {
     55     rows_select = product_size_category<Rows,MaxRows>::value,
     56     cols_select = product_size_category<Cols,MaxCols>::value,
     57     depth_select = product_size_category<Depth,MaxDepth>::value
     58   };
     59   typedef product_type_selector<rows_select, cols_select, depth_select> selector;
     60 
     61 public:
     62   enum {
     63     value = selector::ret,
     64     ret = selector::ret
     65   };
     66 #ifdef EIGEN_DEBUG_PRODUCT
     67   static void debug()
     68   {
     69       EIGEN_DEBUG_VAR(Rows);
     70       EIGEN_DEBUG_VAR(Cols);
     71       EIGEN_DEBUG_VAR(Depth);
     72       EIGEN_DEBUG_VAR(rows_select);
     73       EIGEN_DEBUG_VAR(cols_select);
     74       EIGEN_DEBUG_VAR(depth_select);
     75       EIGEN_DEBUG_VAR(value);
     76   }
     77 #endif
     78 };
     79 
     80 /* The following allows to select the kind of product at compile time
     81  * based on the three dimensions of the product.
     82  * This is a compile time mapping from {1,Small,Large}^3 -> {product types} */
     83 // FIXME I'm not sure the current mapping is the ideal one.
     84 template<int M, int N>  struct product_type_selector<M,N,1>              { enum { ret = OuterProduct }; };
     85 template<int M>         struct product_type_selector<M, 1, 1>            { enum { ret = LazyCoeffBasedProductMode }; };
     86 template<int N>         struct product_type_selector<1, N, 1>            { enum { ret = LazyCoeffBasedProductMode }; };
     87 template<int Depth>     struct product_type_selector<1,    1,    Depth>  { enum { ret = InnerProduct }; };
     88 template<>              struct product_type_selector<1,    1,    1>      { enum { ret = InnerProduct }; };
     89 template<>              struct product_type_selector<Small,1,    Small>  { enum { ret = CoeffBasedProductMode }; };
     90 template<>              struct product_type_selector<1,    Small,Small>  { enum { ret = CoeffBasedProductMode }; };
     91 template<>              struct product_type_selector<Small,Small,Small>  { enum { ret = CoeffBasedProductMode }; };
     92 template<>              struct product_type_selector<Small, Small, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
     93 template<>              struct product_type_selector<Small, Large, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
     94 template<>              struct product_type_selector<Large, Small, 1>    { enum { ret = LazyCoeffBasedProductMode }; };
     95 template<>              struct product_type_selector<1,    Large,Small>  { enum { ret = CoeffBasedProductMode }; };
     96 template<>              struct product_type_selector<1,    Large,Large>  { enum { ret = GemvProduct }; };
     97 template<>              struct product_type_selector<1,    Small,Large>  { enum { ret = CoeffBasedProductMode }; };
     98 template<>              struct product_type_selector<Large,1,    Small>  { enum { ret = CoeffBasedProductMode }; };
     99 template<>              struct product_type_selector<Large,1,    Large>  { enum { ret = GemvProduct }; };
    100 template<>              struct product_type_selector<Small,1,    Large>  { enum { ret = CoeffBasedProductMode }; };
    101 template<>              struct product_type_selector<Small,Small,Large>  { enum { ret = GemmProduct }; };
    102 template<>              struct product_type_selector<Large,Small,Large>  { enum { ret = GemmProduct }; };
    103 template<>              struct product_type_selector<Small,Large,Large>  { enum { ret = GemmProduct }; };
    104 template<>              struct product_type_selector<Large,Large,Large>  { enum { ret = GemmProduct }; };
    105 template<>              struct product_type_selector<Large,Small,Small>  { enum { ret = CoeffBasedProductMode }; };
    106 template<>              struct product_type_selector<Small,Large,Small>  { enum { ret = CoeffBasedProductMode }; };
    107 template<>              struct product_type_selector<Large,Large,Small>  { enum { ret = GemmProduct }; };
    108 
    109 } // end namespace internal
    110 
    111 /***********************************************************************
    112 *  Implementation of Inner Vector Vector Product
    113 ***********************************************************************/
    114 
    115 // FIXME : maybe the "inner product" could return a Scalar
    116 // instead of a 1x1 matrix ??
    117 // Pro: more natural for the user
    118 // Cons: this could be a problem if in a meta unrolled algorithm a matrix-matrix
    119 // product ends up to a row-vector times col-vector product... To tackle this use
    120 // case, we could have a specialization for Block<MatrixType,1,1> with: operator=(Scalar x);
    121 
    122 /***********************************************************************
    123 *  Implementation of Outer Vector Vector Product
    124 ***********************************************************************/
    125 
    126 /***********************************************************************
    127 *  Implementation of General Matrix Vector Product
    128 ***********************************************************************/
    129 
    130 /*  According to the shape/flags of the matrix we have to distinghish 3 different cases:
    131  *   1 - the matrix is col-major, BLAS compatible and M is large => call fast BLAS-like colmajor routine
    132  *   2 - the matrix is row-major, BLAS compatible and N is large => call fast BLAS-like rowmajor routine
    133  *   3 - all other cases are handled using a simple loop along the outer-storage direction.
    134  *  Therefore we need a lower level meta selector.
    135  *  Furthermore, if the matrix is the rhs, then the product has to be transposed.
    136  */
    137 namespace internal {
    138 
    139 template<int Side, int StorageOrder, bool BlasCompatible>
    140 struct gemv_dense_selector;
    141 
    142 } // end namespace internal
    143 
    144 namespace internal {
    145 
    146 template<typename Scalar,int Size,int MaxSize,bool Cond> struct gemv_static_vector_if;
    147 
    148 template<typename Scalar,int Size,int MaxSize>
    149 struct gemv_static_vector_if<Scalar,Size,MaxSize,false>
    150 {
    151   EIGEN_STRONG_INLINE  Scalar* data() { eigen_internal_assert(false && "should never be called"); return 0; }
    152 };
    153 
    154 template<typename Scalar,int Size>
    155 struct gemv_static_vector_if<Scalar,Size,Dynamic,true>
    156 {
    157   EIGEN_STRONG_INLINE Scalar* data() { return 0; }
    158 };
    159 
    160 template<typename Scalar,int Size,int MaxSize>
    161 struct gemv_static_vector_if<Scalar,Size,MaxSize,true>
    162 {
    163   enum {
    164     ForceAlignment  = internal::packet_traits<Scalar>::Vectorizable,
    165     PacketSize      = internal::packet_traits<Scalar>::size
    166   };
    167   #if EIGEN_MAX_STATIC_ALIGN_BYTES!=0
    168   internal::plain_array<Scalar,EIGEN_SIZE_MIN_PREFER_FIXED(Size,MaxSize),0,EIGEN_PLAIN_ENUM_MIN(AlignedMax,PacketSize)> m_data;
    169   EIGEN_STRONG_INLINE Scalar* data() { return m_data.array; }
    170   #else
    171   // Some architectures cannot align on the stack,
    172   // => let's manually enforce alignment by allocating more data and return the address of the first aligned element.
    173   internal::plain_array<Scalar,EIGEN_SIZE_MIN_PREFER_FIXED(Size,MaxSize)+(ForceAlignment?EIGEN_MAX_ALIGN_BYTES:0),0> m_data;
    174   EIGEN_STRONG_INLINE Scalar* data() {
    175     return ForceAlignment
    176             ? reinterpret_cast<Scalar*>((internal::UIntPtr(m_data.array) & ~(std::size_t(EIGEN_MAX_ALIGN_BYTES-1))) + EIGEN_MAX_ALIGN_BYTES)
    177             : m_data.array;
    178   }
    179   #endif
    180 };
    181 
    182 // The vector is on the left => transposition
    183 template<int StorageOrder, bool BlasCompatible>
    184 struct gemv_dense_selector<OnTheLeft,StorageOrder,BlasCompatible>
    185 {
    186   template<typename Lhs, typename Rhs, typename Dest>
    187   static void run(const Lhs &lhs, const Rhs &rhs, Dest& dest, const typename Dest::Scalar& alpha)
    188   {
    189     Transpose<Dest> destT(dest);
    190     enum { OtherStorageOrder = StorageOrder == RowMajor ? ColMajor : RowMajor };
    191     gemv_dense_selector<OnTheRight,OtherStorageOrder,BlasCompatible>
    192       ::run(rhs.transpose(), lhs.transpose(), destT, alpha);
    193   }
    194 };
    195 
    196 template<> struct gemv_dense_selector<OnTheRight,ColMajor,true>
    197 {
    198   template<typename Lhs, typename Rhs, typename Dest>
    199   static inline void run(const Lhs &lhs, const Rhs &rhs, Dest& dest, const typename Dest::Scalar& alpha)
    200   {
    201     typedef typename Lhs::Scalar   LhsScalar;
    202     typedef typename Rhs::Scalar   RhsScalar;
    203     typedef typename Dest::Scalar  ResScalar;
    204     typedef typename Dest::RealScalar  RealScalar;
    205 
    206     typedef internal::blas_traits<Lhs> LhsBlasTraits;
    207     typedef typename LhsBlasTraits::DirectLinearAccessType ActualLhsType;
    208     typedef internal::blas_traits<Rhs> RhsBlasTraits;
    209     typedef typename RhsBlasTraits::DirectLinearAccessType ActualRhsType;
    210 
    211     typedef Map<Matrix<ResScalar,Dynamic,1>, EIGEN_PLAIN_ENUM_MIN(AlignedMax,internal::packet_traits<ResScalar>::size)> MappedDest;
    212 
    213     ActualLhsType actualLhs = LhsBlasTraits::extract(lhs);
    214     ActualRhsType actualRhs = RhsBlasTraits::extract(rhs);
    215 
    216     ResScalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(lhs)
    217                                   * RhsBlasTraits::extractScalarFactor(rhs);
    218 
    219     // make sure Dest is a compile-time vector type (bug 1166)
    220     typedef typename conditional<Dest::IsVectorAtCompileTime, Dest, typename Dest::ColXpr>::type ActualDest;
    221 
    222     enum {
    223       // FIXME find a way to allow an inner stride on the result if packet_traits<Scalar>::size==1
    224       // on, the other hand it is good for the cache to pack the vector anyways...
    225       EvalToDestAtCompileTime = (ActualDest::InnerStrideAtCompileTime==1),
    226       ComplexByReal = (NumTraits<LhsScalar>::IsComplex) && (!NumTraits<RhsScalar>::IsComplex),
    227       MightCannotUseDest = (!EvalToDestAtCompileTime) || ComplexByReal
    228     };
    229 
    230     typedef const_blas_data_mapper<LhsScalar,Index,ColMajor> LhsMapper;
    231     typedef const_blas_data_mapper<RhsScalar,Index,RowMajor> RhsMapper;
    232     RhsScalar compatibleAlpha = get_factor<ResScalar,RhsScalar>::run(actualAlpha);
    233 
    234     if(!MightCannotUseDest)
    235     {
    236       // shortcut if we are sure to be able to use dest directly,
    237       // this ease the compiler to generate cleaner and more optimzized code for most common cases
    238       general_matrix_vector_product
    239           <Index,LhsScalar,LhsMapper,ColMajor,LhsBlasTraits::NeedToConjugate,RhsScalar,RhsMapper,RhsBlasTraits::NeedToConjugate>::run(
    240           actualLhs.rows(), actualLhs.cols(),
    241           LhsMapper(actualLhs.data(), actualLhs.outerStride()),
    242           RhsMapper(actualRhs.data(), actualRhs.innerStride()),
    243           dest.data(), 1,
    244           compatibleAlpha);
    245     }
    246     else
    247     {
    248       gemv_static_vector_if<ResScalar,ActualDest::SizeAtCompileTime,ActualDest::MaxSizeAtCompileTime,MightCannotUseDest> static_dest;
    249 
    250       const bool alphaIsCompatible = (!ComplexByReal) || (numext::imag(actualAlpha)==RealScalar(0));
    251       const bool evalToDest = EvalToDestAtCompileTime && alphaIsCompatible;
    252 
    253       ei_declare_aligned_stack_constructed_variable(ResScalar,actualDestPtr,dest.size(),
    254                                                     evalToDest ? dest.data() : static_dest.data());
    255 
    256       if(!evalToDest)
    257       {
    258         #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    259         Index size = dest.size();
    260         EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    261         #endif
    262         if(!alphaIsCompatible)
    263         {
    264           MappedDest(actualDestPtr, dest.size()).setZero();
    265           compatibleAlpha = RhsScalar(1);
    266         }
    267         else
    268           MappedDest(actualDestPtr, dest.size()) = dest;
    269       }
    270 
    271       general_matrix_vector_product
    272           <Index,LhsScalar,LhsMapper,ColMajor,LhsBlasTraits::NeedToConjugate,RhsScalar,RhsMapper,RhsBlasTraits::NeedToConjugate>::run(
    273           actualLhs.rows(), actualLhs.cols(),
    274           LhsMapper(actualLhs.data(), actualLhs.outerStride()),
    275           RhsMapper(actualRhs.data(), actualRhs.innerStride()),
    276           actualDestPtr, 1,
    277           compatibleAlpha);
    278 
    279       if (!evalToDest)
    280       {
    281         if(!alphaIsCompatible)
    282           dest.matrix() += actualAlpha * MappedDest(actualDestPtr, dest.size());
    283         else
    284           dest = MappedDest(actualDestPtr, dest.size());
    285       }
    286     }
    287   }
    288 };
    289 
    290 template<> struct gemv_dense_selector<OnTheRight,RowMajor,true>
    291 {
    292   template<typename Lhs, typename Rhs, typename Dest>
    293   static void run(const Lhs &lhs, const Rhs &rhs, Dest& dest, const typename Dest::Scalar& alpha)
    294   {
    295     typedef typename Lhs::Scalar   LhsScalar;
    296     typedef typename Rhs::Scalar   RhsScalar;
    297     typedef typename Dest::Scalar  ResScalar;
    298 
    299     typedef internal::blas_traits<Lhs> LhsBlasTraits;
    300     typedef typename LhsBlasTraits::DirectLinearAccessType ActualLhsType;
    301     typedef internal::blas_traits<Rhs> RhsBlasTraits;
    302     typedef typename RhsBlasTraits::DirectLinearAccessType ActualRhsType;
    303     typedef typename internal::remove_all<ActualRhsType>::type ActualRhsTypeCleaned;
    304 
    305     typename add_const<ActualLhsType>::type actualLhs = LhsBlasTraits::extract(lhs);
    306     typename add_const<ActualRhsType>::type actualRhs = RhsBlasTraits::extract(rhs);
    307 
    308     ResScalar actualAlpha = alpha * LhsBlasTraits::extractScalarFactor(lhs)
    309                                   * RhsBlasTraits::extractScalarFactor(rhs);
    310 
    311     enum {
    312       // FIXME find a way to allow an inner stride on the result if packet_traits<Scalar>::size==1
    313       // on, the other hand it is good for the cache to pack the vector anyways...
    314       DirectlyUseRhs = ActualRhsTypeCleaned::InnerStrideAtCompileTime==1
    315     };
    316 
    317     gemv_static_vector_if<RhsScalar,ActualRhsTypeCleaned::SizeAtCompileTime,ActualRhsTypeCleaned::MaxSizeAtCompileTime,!DirectlyUseRhs> static_rhs;
    318 
    319     ei_declare_aligned_stack_constructed_variable(RhsScalar,actualRhsPtr,actualRhs.size(),
    320         DirectlyUseRhs ? const_cast<RhsScalar*>(actualRhs.data()) : static_rhs.data());
    321 
    322     if(!DirectlyUseRhs)
    323     {
    324       #ifdef EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    325       Index size = actualRhs.size();
    326       EIGEN_DENSE_STORAGE_CTOR_PLUGIN
    327       #endif
    328       Map<typename ActualRhsTypeCleaned::PlainObject>(actualRhsPtr, actualRhs.size()) = actualRhs;
    329     }
    330 
    331     typedef const_blas_data_mapper<LhsScalar,Index,RowMajor> LhsMapper;
    332     typedef const_blas_data_mapper<RhsScalar,Index,ColMajor> RhsMapper;
    333     general_matrix_vector_product
    334         <Index,LhsScalar,LhsMapper,RowMajor,LhsBlasTraits::NeedToConjugate,RhsScalar,RhsMapper,RhsBlasTraits::NeedToConjugate>::run(
    335         actualLhs.rows(), actualLhs.cols(),
    336         LhsMapper(actualLhs.data(), actualLhs.outerStride()),
    337         RhsMapper(actualRhsPtr, 1),
    338         dest.data(), dest.col(0).innerStride(), //NOTE  if dest is not a vector at compile-time, then dest.innerStride() might be wrong. (bug 1166)
    339         actualAlpha);
    340   }
    341 };
    342 
    343 template<> struct gemv_dense_selector<OnTheRight,ColMajor,false>
    344 {
    345   template<typename Lhs, typename Rhs, typename Dest>
    346   static void run(const Lhs &lhs, const Rhs &rhs, Dest& dest, const typename Dest::Scalar& alpha)
    347   {
    348     EIGEN_STATIC_ASSERT((!nested_eval<Lhs,1>::Evaluate),EIGEN_INTERNAL_COMPILATION_ERROR_OR_YOU_MADE_A_PROGRAMMING_MISTAKE);
    349     // TODO if rhs is large enough it might be beneficial to make sure that dest is sequentially stored in memory, otherwise use a temp
    350     typename nested_eval<Rhs,1>::type actual_rhs(rhs);
    351     const Index size = rhs.rows();
    352     for(Index k=0; k<size; ++k)
    353       dest += (alpha*actual_rhs.coeff(k)) * lhs.col(k);
    354   }
    355 };
    356 
    357 template<> struct gemv_dense_selector<OnTheRight,RowMajor,false>
    358 {
    359   template<typename Lhs, typename Rhs, typename Dest>
    360   static void run(const Lhs &lhs, const Rhs &rhs, Dest& dest, const typename Dest::Scalar& alpha)
    361   {
    362     EIGEN_STATIC_ASSERT((!nested_eval<Lhs,1>::Evaluate),EIGEN_INTERNAL_COMPILATION_ERROR_OR_YOU_MADE_A_PROGRAMMING_MISTAKE);
    363     typename nested_eval<Rhs,Lhs::RowsAtCompileTime>::type actual_rhs(rhs);
    364     const Index rows = dest.rows();
    365     for(Index i=0; i<rows; ++i)
    366       dest.coeffRef(i) += alpha * (lhs.row(i).cwiseProduct(actual_rhs.transpose())).sum();
    367   }
    368 };
    369 
    370 } // end namespace internal
    371 
    372 /***************************************************************************
    373 * Implementation of matrix base methods
    374 ***************************************************************************/
    375 
    376 /** \returns the matrix product of \c *this and \a other.
    377   *
    378   * \note If instead of the matrix product you want the coefficient-wise product, see Cwise::operator*().
    379   *
    380   * \sa lazyProduct(), operator*=(const MatrixBase&), Cwise::operator*()
    381   */
    382 #ifndef __CUDACC__
    383 
    384 template<typename Derived>
    385 template<typename OtherDerived>
    386 inline const Product<Derived, OtherDerived>
    387 MatrixBase<Derived>::operator*(const MatrixBase<OtherDerived> &other) const
    388 {
    389   // A note regarding the function declaration: In MSVC, this function will sometimes
    390   // not be inlined since DenseStorage is an unwindable object for dynamic
    391   // matrices and product types are holding a member to store the result.
    392   // Thus it does not help tagging this function with EIGEN_STRONG_INLINE.
    393   enum {
    394     ProductIsValid =  Derived::ColsAtCompileTime==Dynamic
    395                    || OtherDerived::RowsAtCompileTime==Dynamic
    396                    || int(Derived::ColsAtCompileTime)==int(OtherDerived::RowsAtCompileTime),
    397     AreVectors = Derived::IsVectorAtCompileTime && OtherDerived::IsVectorAtCompileTime,
    398     SameSizes = EIGEN_PREDICATE_SAME_MATRIX_SIZE(Derived,OtherDerived)
    399   };
    400   // note to the lost user:
    401   //    * for a dot product use: v1.dot(v2)
    402   //    * for a coeff-wise product use: v1.cwiseProduct(v2)
    403   EIGEN_STATIC_ASSERT(ProductIsValid || !(AreVectors && SameSizes),
    404     INVALID_VECTOR_VECTOR_PRODUCT__IF_YOU_WANTED_A_DOT_OR_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTIONS)
    405   EIGEN_STATIC_ASSERT(ProductIsValid || !(SameSizes && !AreVectors),
    406     INVALID_MATRIX_PRODUCT__IF_YOU_WANTED_A_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTION)
    407   EIGEN_STATIC_ASSERT(ProductIsValid || SameSizes, INVALID_MATRIX_PRODUCT)
    408 #ifdef EIGEN_DEBUG_PRODUCT
    409   internal::product_type<Derived,OtherDerived>::debug();
    410 #endif
    411 
    412   return Product<Derived, OtherDerived>(derived(), other.derived());
    413 }
    414 
    415 #endif // __CUDACC__
    416 
    417 /** \returns an expression of the matrix product of \c *this and \a other without implicit evaluation.
    418   *
    419   * The returned product will behave like any other expressions: the coefficients of the product will be
    420   * computed once at a time as requested. This might be useful in some extremely rare cases when only
    421   * a small and no coherent fraction of the result's coefficients have to be computed.
    422   *
    423   * \warning This version of the matrix product can be much much slower. So use it only if you know
    424   * what you are doing and that you measured a true speed improvement.
    425   *
    426   * \sa operator*(const MatrixBase&)
    427   */
    428 template<typename Derived>
    429 template<typename OtherDerived>
    430 const Product<Derived,OtherDerived,LazyProduct>
    431 MatrixBase<Derived>::lazyProduct(const MatrixBase<OtherDerived> &other) const
    432 {
    433   enum {
    434     ProductIsValid =  Derived::ColsAtCompileTime==Dynamic
    435                    || OtherDerived::RowsAtCompileTime==Dynamic
    436                    || int(Derived::ColsAtCompileTime)==int(OtherDerived::RowsAtCompileTime),
    437     AreVectors = Derived::IsVectorAtCompileTime && OtherDerived::IsVectorAtCompileTime,
    438     SameSizes = EIGEN_PREDICATE_SAME_MATRIX_SIZE(Derived,OtherDerived)
    439   };
    440   // note to the lost user:
    441   //    * for a dot product use: v1.dot(v2)
    442   //    * for a coeff-wise product use: v1.cwiseProduct(v2)
    443   EIGEN_STATIC_ASSERT(ProductIsValid || !(AreVectors && SameSizes),
    444     INVALID_VECTOR_VECTOR_PRODUCT__IF_YOU_WANTED_A_DOT_OR_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTIONS)
    445   EIGEN_STATIC_ASSERT(ProductIsValid || !(SameSizes && !AreVectors),
    446     INVALID_MATRIX_PRODUCT__IF_YOU_WANTED_A_COEFF_WISE_PRODUCT_YOU_MUST_USE_THE_EXPLICIT_FUNCTION)
    447   EIGEN_STATIC_ASSERT(ProductIsValid || SameSizes, INVALID_MATRIX_PRODUCT)
    448 
    449   return Product<Derived,OtherDerived,LazyProduct>(derived(), other.derived());
    450 }
    451 
    452 } // end namespace Eigen
    453 
    454 #endif // EIGEN_PRODUCT_H
    455