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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@gmail.com>
5 // Copyright (C) 2008-2011 Gael Guennebaud <gael.guennebaud@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
debugproduct_type67   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