cart-elc

Source code for CART-ELC
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ProductEvaluators.h (53832B)


      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) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
      6 // Copyright (C) 2011 Jitse Niesen <jitse@maths.leeds.ac.uk>
      7 //
      8 // This Source Code Form is subject to the terms of the Mozilla
      9 // Public License v. 2.0. If a copy of the MPL was not distributed
     10 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
     11 
     12 
     13 #ifndef EIGEN_PRODUCTEVALUATORS_H
     14 #define EIGEN_PRODUCTEVALUATORS_H
     15 
     16 namespace Eigen {
     17 
     18 namespace internal {
     19 
     20 /** \internal
     21   * Evaluator of a product expression.
     22   * Since products require special treatments to handle all possible cases,
     23   * we simply defer the evaluation logic to a product_evaluator class
     24   * which offers more partial specialization possibilities.
     25   *
     26   * \sa class product_evaluator
     27   */
     28 template<typename Lhs, typename Rhs, int Options>
     29 struct evaluator<Product<Lhs, Rhs, Options> >
     30  : public product_evaluator<Product<Lhs, Rhs, Options> >
     31 {
     32   typedef Product<Lhs, Rhs, Options> XprType;
     33   typedef product_evaluator<XprType> Base;
     34 
     35   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE explicit evaluator(const XprType& xpr) : Base(xpr) {}
     36 };
     37 
     38 // Catch "scalar * ( A * B )" and transform it to "(A*scalar) * B"
     39 // TODO we should apply that rule only if that's really helpful
     40 template<typename Lhs, typename Rhs, typename Scalar1, typename Scalar2, typename Plain1>
     41 struct evaluator_assume_aliasing<CwiseBinaryOp<internal::scalar_product_op<Scalar1,Scalar2>,
     42                                                const CwiseNullaryOp<internal::scalar_constant_op<Scalar1>, Plain1>,
     43                                                const Product<Lhs, Rhs, DefaultProduct> > >
     44 {
     45   static const bool value = true;
     46 };
     47 template<typename Lhs, typename Rhs, typename Scalar1, typename Scalar2, typename Plain1>
     48 struct evaluator<CwiseBinaryOp<internal::scalar_product_op<Scalar1,Scalar2>,
     49                                const CwiseNullaryOp<internal::scalar_constant_op<Scalar1>, Plain1>,
     50                                const Product<Lhs, Rhs, DefaultProduct> > >
     51  : public evaluator<Product<EIGEN_SCALAR_BINARYOP_EXPR_RETURN_TYPE(Scalar1,Lhs,product), Rhs, DefaultProduct> >
     52 {
     53   typedef CwiseBinaryOp<internal::scalar_product_op<Scalar1,Scalar2>,
     54                                const CwiseNullaryOp<internal::scalar_constant_op<Scalar1>, Plain1>,
     55                                const Product<Lhs, Rhs, DefaultProduct> > XprType;
     56   typedef evaluator<Product<EIGEN_SCALAR_BINARYOP_EXPR_RETURN_TYPE(Scalar1,Lhs,product), Rhs, DefaultProduct> > Base;
     57 
     58   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE explicit evaluator(const XprType& xpr)
     59     : Base(xpr.lhs().functor().m_other * xpr.rhs().lhs() * xpr.rhs().rhs())
     60   {}
     61 };
     62 
     63 
     64 template<typename Lhs, typename Rhs, int DiagIndex>
     65 struct evaluator<Diagonal<const Product<Lhs, Rhs, DefaultProduct>, DiagIndex> >
     66  : public evaluator<Diagonal<const Product<Lhs, Rhs, LazyProduct>, DiagIndex> >
     67 {
     68   typedef Diagonal<const Product<Lhs, Rhs, DefaultProduct>, DiagIndex> XprType;
     69   typedef evaluator<Diagonal<const Product<Lhs, Rhs, LazyProduct>, DiagIndex> > Base;
     70 
     71   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE explicit evaluator(const XprType& xpr)
     72     : Base(Diagonal<const Product<Lhs, Rhs, LazyProduct>, DiagIndex>(
     73         Product<Lhs, Rhs, LazyProduct>(xpr.nestedExpression().lhs(), xpr.nestedExpression().rhs()),
     74         xpr.index() ))
     75   {}
     76 };
     77 
     78 
     79 // Helper class to perform a matrix product with the destination at hand.
     80 // Depending on the sizes of the factors, there are different evaluation strategies
     81 // as controlled by internal::product_type.
     82 template< typename Lhs, typename Rhs,
     83           typename LhsShape = typename evaluator_traits<Lhs>::Shape,
     84           typename RhsShape = typename evaluator_traits<Rhs>::Shape,
     85           int ProductType = internal::product_type<Lhs,Rhs>::value>
     86 struct generic_product_impl;
     87 
     88 template<typename Lhs, typename Rhs>
     89 struct evaluator_assume_aliasing<Product<Lhs, Rhs, DefaultProduct> > {
     90   static const bool value = true;
     91 };
     92 
     93 // This is the default evaluator implementation for products:
     94 // It creates a temporary and call generic_product_impl
     95 template<typename Lhs, typename Rhs, int Options, int ProductTag, typename LhsShape, typename RhsShape>
     96 struct product_evaluator<Product<Lhs, Rhs, Options>, ProductTag, LhsShape, RhsShape>
     97   : public evaluator<typename Product<Lhs, Rhs, Options>::PlainObject>
     98 {
     99   typedef Product<Lhs, Rhs, Options> XprType;
    100   typedef typename XprType::PlainObject PlainObject;
    101   typedef evaluator<PlainObject> Base;
    102   enum {
    103     Flags = Base::Flags | EvalBeforeNestingBit
    104   };
    105 
    106   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    107   explicit product_evaluator(const XprType& xpr)
    108     : m_result(xpr.rows(), xpr.cols())
    109   {
    110     ::new (static_cast<Base*>(this)) Base(m_result);
    111 
    112 // FIXME shall we handle nested_eval here?,
    113 // if so, then we must take care at removing the call to nested_eval in the specializations (e.g., in permutation_matrix_product, transposition_matrix_product, etc.)
    114 //     typedef typename internal::nested_eval<Lhs,Rhs::ColsAtCompileTime>::type LhsNested;
    115 //     typedef typename internal::nested_eval<Rhs,Lhs::RowsAtCompileTime>::type RhsNested;
    116 //     typedef typename internal::remove_all<LhsNested>::type LhsNestedCleaned;
    117 //     typedef typename internal::remove_all<RhsNested>::type RhsNestedCleaned;
    118 //
    119 //     const LhsNested lhs(xpr.lhs());
    120 //     const RhsNested rhs(xpr.rhs());
    121 //
    122 //     generic_product_impl<LhsNestedCleaned, RhsNestedCleaned>::evalTo(m_result, lhs, rhs);
    123 
    124     generic_product_impl<Lhs, Rhs, LhsShape, RhsShape, ProductTag>::evalTo(m_result, xpr.lhs(), xpr.rhs());
    125   }
    126 
    127 protected:
    128   PlainObject m_result;
    129 };
    130 
    131 // The following three shortcuts are enabled only if the scalar types match exactly.
    132 // TODO: we could enable them for different scalar types when the product is not vectorized.
    133 
    134 // Dense = Product
    135 template< typename DstXprType, typename Lhs, typename Rhs, int Options, typename Scalar>
    136 struct Assignment<DstXprType, Product<Lhs,Rhs,Options>, internal::assign_op<Scalar,Scalar>, Dense2Dense,
    137   typename enable_if<(Options==DefaultProduct || Options==AliasFreeProduct)>::type>
    138 {
    139   typedef Product<Lhs,Rhs,Options> SrcXprType;
    140   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    141   void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<Scalar,Scalar> &)
    142   {
    143     Index dstRows = src.rows();
    144     Index dstCols = src.cols();
    145     if((dst.rows()!=dstRows) || (dst.cols()!=dstCols))
    146       dst.resize(dstRows, dstCols);
    147     // FIXME shall we handle nested_eval here?
    148     generic_product_impl<Lhs, Rhs>::evalTo(dst, src.lhs(), src.rhs());
    149   }
    150 };
    151 
    152 // Dense += Product
    153 template< typename DstXprType, typename Lhs, typename Rhs, int Options, typename Scalar>
    154 struct Assignment<DstXprType, Product<Lhs,Rhs,Options>, internal::add_assign_op<Scalar,Scalar>, Dense2Dense,
    155   typename enable_if<(Options==DefaultProduct || Options==AliasFreeProduct)>::type>
    156 {
    157   typedef Product<Lhs,Rhs,Options> SrcXprType;
    158   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    159   void run(DstXprType &dst, const SrcXprType &src, const internal::add_assign_op<Scalar,Scalar> &)
    160   {
    161     eigen_assert(dst.rows() == src.rows() && dst.cols() == src.cols());
    162     // FIXME shall we handle nested_eval here?
    163     generic_product_impl<Lhs, Rhs>::addTo(dst, src.lhs(), src.rhs());
    164   }
    165 };
    166 
    167 // Dense -= Product
    168 template< typename DstXprType, typename Lhs, typename Rhs, int Options, typename Scalar>
    169 struct Assignment<DstXprType, Product<Lhs,Rhs,Options>, internal::sub_assign_op<Scalar,Scalar>, Dense2Dense,
    170   typename enable_if<(Options==DefaultProduct || Options==AliasFreeProduct)>::type>
    171 {
    172   typedef Product<Lhs,Rhs,Options> SrcXprType;
    173   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    174   void run(DstXprType &dst, const SrcXprType &src, const internal::sub_assign_op<Scalar,Scalar> &)
    175   {
    176     eigen_assert(dst.rows() == src.rows() && dst.cols() == src.cols());
    177     // FIXME shall we handle nested_eval here?
    178     generic_product_impl<Lhs, Rhs>::subTo(dst, src.lhs(), src.rhs());
    179   }
    180 };
    181 
    182 
    183 // Dense ?= scalar * Product
    184 // TODO we should apply that rule if that's really helpful
    185 // for instance, this is not good for inner products
    186 template< typename DstXprType, typename Lhs, typename Rhs, typename AssignFunc, typename Scalar, typename ScalarBis, typename Plain>
    187 struct Assignment<DstXprType, CwiseBinaryOp<internal::scalar_product_op<ScalarBis,Scalar>, const CwiseNullaryOp<internal::scalar_constant_op<ScalarBis>,Plain>,
    188                                            const Product<Lhs,Rhs,DefaultProduct> >, AssignFunc, Dense2Dense>
    189 {
    190   typedef CwiseBinaryOp<internal::scalar_product_op<ScalarBis,Scalar>,
    191                         const CwiseNullaryOp<internal::scalar_constant_op<ScalarBis>,Plain>,
    192                         const Product<Lhs,Rhs,DefaultProduct> > SrcXprType;
    193   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    194   void run(DstXprType &dst, const SrcXprType &src, const AssignFunc& func)
    195   {
    196     call_assignment_no_alias(dst, (src.lhs().functor().m_other * src.rhs().lhs())*src.rhs().rhs(), func);
    197   }
    198 };
    199 
    200 //----------------------------------------
    201 // Catch "Dense ?= xpr + Product<>" expression to save one temporary
    202 // FIXME we could probably enable these rules for any product, i.e., not only Dense and DefaultProduct
    203 
    204 template<typename OtherXpr, typename Lhs, typename Rhs>
    205 struct evaluator_assume_aliasing<CwiseBinaryOp<internal::scalar_sum_op<typename OtherXpr::Scalar,typename Product<Lhs,Rhs,DefaultProduct>::Scalar>, const OtherXpr,
    206                                                const Product<Lhs,Rhs,DefaultProduct> >, DenseShape > {
    207   static const bool value = true;
    208 };
    209 
    210 template<typename OtherXpr, typename Lhs, typename Rhs>
    211 struct evaluator_assume_aliasing<CwiseBinaryOp<internal::scalar_difference_op<typename OtherXpr::Scalar,typename Product<Lhs,Rhs,DefaultProduct>::Scalar>, const OtherXpr,
    212                                                const Product<Lhs,Rhs,DefaultProduct> >, DenseShape > {
    213   static const bool value = true;
    214 };
    215 
    216 template<typename DstXprType, typename OtherXpr, typename ProductType, typename Func1, typename Func2>
    217 struct assignment_from_xpr_op_product
    218 {
    219   template<typename SrcXprType, typename InitialFunc>
    220   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    221   void run(DstXprType &dst, const SrcXprType &src, const InitialFunc& /*func*/)
    222   {
    223     call_assignment_no_alias(dst, src.lhs(), Func1());
    224     call_assignment_no_alias(dst, src.rhs(), Func2());
    225   }
    226 };
    227 
    228 #define EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(ASSIGN_OP,BINOP,ASSIGN_OP2) \
    229   template< typename DstXprType, typename OtherXpr, typename Lhs, typename Rhs, typename DstScalar, typename SrcScalar, typename OtherScalar,typename ProdScalar> \
    230   struct Assignment<DstXprType, CwiseBinaryOp<internal::BINOP<OtherScalar,ProdScalar>, const OtherXpr, \
    231                                             const Product<Lhs,Rhs,DefaultProduct> >, internal::ASSIGN_OP<DstScalar,SrcScalar>, Dense2Dense> \
    232     : assignment_from_xpr_op_product<DstXprType, OtherXpr, Product<Lhs,Rhs,DefaultProduct>, internal::ASSIGN_OP<DstScalar,OtherScalar>, internal::ASSIGN_OP2<DstScalar,ProdScalar> > \
    233   {}
    234 
    235 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(assign_op,    scalar_sum_op,add_assign_op);
    236 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(add_assign_op,scalar_sum_op,add_assign_op);
    237 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(sub_assign_op,scalar_sum_op,sub_assign_op);
    238 
    239 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(assign_op,    scalar_difference_op,sub_assign_op);
    240 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(add_assign_op,scalar_difference_op,sub_assign_op);
    241 EIGEN_CATCH_ASSIGN_XPR_OP_PRODUCT(sub_assign_op,scalar_difference_op,add_assign_op);
    242 
    243 //----------------------------------------
    244 
    245 template<typename Lhs, typename Rhs>
    246 struct generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,InnerProduct>
    247 {
    248   template<typename Dst>
    249   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    250   {
    251     dst.coeffRef(0,0) = (lhs.transpose().cwiseProduct(rhs)).sum();
    252   }
    253 
    254   template<typename Dst>
    255   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void addTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    256   {
    257     dst.coeffRef(0,0) += (lhs.transpose().cwiseProduct(rhs)).sum();
    258   }
    259 
    260   template<typename Dst>
    261   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void subTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    262   { dst.coeffRef(0,0) -= (lhs.transpose().cwiseProduct(rhs)).sum(); }
    263 };
    264 
    265 
    266 /***********************************************************************
    267 *  Implementation of outer dense * dense vector product
    268 ***********************************************************************/
    269 
    270 // Column major result
    271 template<typename Dst, typename Lhs, typename Rhs, typename Func>
    272 void EIGEN_DEVICE_FUNC outer_product_selector_run(Dst& dst, const Lhs &lhs, const Rhs &rhs, const Func& func, const false_type&)
    273 {
    274   evaluator<Rhs> rhsEval(rhs);
    275   ei_declare_local_nested_eval(Lhs,lhs,Rhs::SizeAtCompileTime,actual_lhs);
    276   // FIXME if cols is large enough, then it might be useful to make sure that lhs is sequentially stored
    277   // FIXME not very good if rhs is real and lhs complex while alpha is real too
    278   const Index cols = dst.cols();
    279   for (Index j=0; j<cols; ++j)
    280     func(dst.col(j), rhsEval.coeff(Index(0),j) * actual_lhs);
    281 }
    282 
    283 // Row major result
    284 template<typename Dst, typename Lhs, typename Rhs, typename Func>
    285 void EIGEN_DEVICE_FUNC outer_product_selector_run(Dst& dst, const Lhs &lhs, const Rhs &rhs, const Func& func, const true_type&)
    286 {
    287   evaluator<Lhs> lhsEval(lhs);
    288   ei_declare_local_nested_eval(Rhs,rhs,Lhs::SizeAtCompileTime,actual_rhs);
    289   // FIXME if rows is large enough, then it might be useful to make sure that rhs is sequentially stored
    290   // FIXME not very good if lhs is real and rhs complex while alpha is real too
    291   const Index rows = dst.rows();
    292   for (Index i=0; i<rows; ++i)
    293     func(dst.row(i), lhsEval.coeff(i,Index(0)) * actual_rhs);
    294 }
    295 
    296 template<typename Lhs, typename Rhs>
    297 struct generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,OuterProduct>
    298 {
    299   template<typename T> struct is_row_major : internal::conditional<(int(T::Flags)&RowMajorBit), internal::true_type, internal::false_type>::type {};
    300   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    301 
    302   // TODO it would be nice to be able to exploit our *_assign_op functors for that purpose
    303   struct set  { template<typename Dst, typename Src> EIGEN_DEVICE_FUNC void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived()  = src; } };
    304   struct add  { template<typename Dst, typename Src> EIGEN_DEVICE_FUNC void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived() += src; } };
    305   struct sub  { template<typename Dst, typename Src> EIGEN_DEVICE_FUNC void operator()(const Dst& dst, const Src& src) const { dst.const_cast_derived() -= src; } };
    306   struct adds {
    307     Scalar m_scale;
    308     explicit adds(const Scalar& s) : m_scale(s) {}
    309     template<typename Dst, typename Src> void EIGEN_DEVICE_FUNC operator()(const Dst& dst, const Src& src) const {
    310       dst.const_cast_derived() += m_scale * src;
    311     }
    312   };
    313 
    314   template<typename Dst>
    315   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    316   {
    317     internal::outer_product_selector_run(dst, lhs, rhs, set(), is_row_major<Dst>());
    318   }
    319 
    320   template<typename Dst>
    321   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void addTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    322   {
    323     internal::outer_product_selector_run(dst, lhs, rhs, add(), is_row_major<Dst>());
    324   }
    325 
    326   template<typename Dst>
    327   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void subTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    328   {
    329     internal::outer_product_selector_run(dst, lhs, rhs, sub(), is_row_major<Dst>());
    330   }
    331 
    332   template<typename Dst>
    333   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void scaleAndAddTo(Dst& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    334   {
    335     internal::outer_product_selector_run(dst, lhs, rhs, adds(alpha), is_row_major<Dst>());
    336   }
    337 
    338 };
    339 
    340 
    341 // This base class provides default implementations for evalTo, addTo, subTo, in terms of scaleAndAddTo
    342 template<typename Lhs, typename Rhs, typename Derived>
    343 struct generic_product_impl_base
    344 {
    345   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    346 
    347   template<typename Dst>
    348   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    349   { dst.setZero(); scaleAndAddTo(dst, lhs, rhs, Scalar(1)); }
    350 
    351   template<typename Dst>
    352   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void addTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    353   { scaleAndAddTo(dst,lhs, rhs, Scalar(1)); }
    354 
    355   template<typename Dst>
    356   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void subTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    357   { scaleAndAddTo(dst, lhs, rhs, Scalar(-1)); }
    358 
    359   template<typename Dst>
    360   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void scaleAndAddTo(Dst& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    361   { Derived::scaleAndAddTo(dst,lhs,rhs,alpha); }
    362 
    363 };
    364 
    365 template<typename Lhs, typename Rhs>
    366 struct generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,GemvProduct>
    367   : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,GemvProduct> >
    368 {
    369   typedef typename nested_eval<Lhs,1>::type LhsNested;
    370   typedef typename nested_eval<Rhs,1>::type RhsNested;
    371   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    372   enum { Side = Lhs::IsVectorAtCompileTime ? OnTheLeft : OnTheRight };
    373   typedef typename internal::remove_all<typename internal::conditional<int(Side)==OnTheRight,LhsNested,RhsNested>::type>::type MatrixType;
    374 
    375   template<typename Dest>
    376   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    377   {
    378     // Fallback to inner product if both the lhs and rhs is a runtime vector.
    379     if (lhs.rows() == 1 && rhs.cols() == 1) {
    380       dst.coeffRef(0,0) += alpha * lhs.row(0).conjugate().dot(rhs.col(0));
    381       return;
    382     }
    383     LhsNested actual_lhs(lhs);
    384     RhsNested actual_rhs(rhs);
    385     internal::gemv_dense_selector<Side,
    386                             (int(MatrixType::Flags)&RowMajorBit) ? RowMajor : ColMajor,
    387                             bool(internal::blas_traits<MatrixType>::HasUsableDirectAccess)
    388                            >::run(actual_lhs, actual_rhs, dst, alpha);
    389   }
    390 };
    391 
    392 template<typename Lhs, typename Rhs>
    393 struct generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,CoeffBasedProductMode>
    394 {
    395   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    396 
    397   template<typename Dst>
    398   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    399   {
    400     // Same as: dst.noalias() = lhs.lazyProduct(rhs);
    401     // but easier on the compiler side
    402     call_assignment_no_alias(dst, lhs.lazyProduct(rhs), internal::assign_op<typename Dst::Scalar,Scalar>());
    403   }
    404 
    405   template<typename Dst>
    406   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void addTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    407   {
    408     // dst.noalias() += lhs.lazyProduct(rhs);
    409     call_assignment_no_alias(dst, lhs.lazyProduct(rhs), internal::add_assign_op<typename Dst::Scalar,Scalar>());
    410   }
    411 
    412   template<typename Dst>
    413   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void subTo(Dst& dst, const Lhs& lhs, const Rhs& rhs)
    414   {
    415     // dst.noalias() -= lhs.lazyProduct(rhs);
    416     call_assignment_no_alias(dst, lhs.lazyProduct(rhs), internal::sub_assign_op<typename Dst::Scalar,Scalar>());
    417   }
    418 
    419   // This is a special evaluation path called from generic_product_impl<...,GemmProduct> in file GeneralMatrixMatrix.h
    420   // This variant tries to extract scalar multiples from both the LHS and RHS and factor them out. For instance:
    421   //   dst {,+,-}= (s1*A)*(B*s2)
    422   // will be rewritten as:
    423   //   dst {,+,-}= (s1*s2) * (A.lazyProduct(B))
    424   // There are at least four benefits of doing so:
    425   //  1 - huge performance gain for heap-allocated matrix types as it save costly allocations.
    426   //  2 - it is faster than simply by-passing the heap allocation through stack allocation.
    427   //  3 - it makes this fallback consistent with the heavy GEMM routine.
    428   //  4 - it fully by-passes huge stack allocation attempts when multiplying huge fixed-size matrices.
    429   //      (see https://stackoverflow.com/questions/54738495)
    430   // For small fixed sizes matrices, howver, the gains are less obvious, it is sometimes x2 faster, but sometimes x3 slower,
    431   // and the behavior depends also a lot on the compiler... This is why this re-writting strategy is currently
    432   // enabled only when falling back from the main GEMM.
    433   template<typename Dst, typename Func>
    434   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    435   void eval_dynamic(Dst& dst, const Lhs& lhs, const Rhs& rhs, const Func &func)
    436   {
    437     enum {
    438       HasScalarFactor = blas_traits<Lhs>::HasScalarFactor || blas_traits<Rhs>::HasScalarFactor,
    439       ConjLhs = blas_traits<Lhs>::NeedToConjugate,
    440       ConjRhs = blas_traits<Rhs>::NeedToConjugate
    441     };
    442     // FIXME: in c++11 this should be auto, and extractScalarFactor should also return auto
    443     //        this is important for real*complex_mat
    444     Scalar actualAlpha = combine_scalar_factors<Scalar>(lhs, rhs);
    445 
    446     eval_dynamic_impl(dst,
    447                       blas_traits<Lhs>::extract(lhs).template conjugateIf<ConjLhs>(),
    448                       blas_traits<Rhs>::extract(rhs).template conjugateIf<ConjRhs>(),
    449                       func,
    450                       actualAlpha,
    451                       typename conditional<HasScalarFactor,true_type,false_type>::type());
    452   }
    453 
    454 protected:
    455 
    456   template<typename Dst, typename LhsT, typename RhsT, typename Func, typename Scalar>
    457   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    458   void eval_dynamic_impl(Dst& dst, const LhsT& lhs, const RhsT& rhs, const Func &func, const Scalar&  s /* == 1 */, false_type)
    459   {
    460     EIGEN_UNUSED_VARIABLE(s);
    461     eigen_internal_assert(s==Scalar(1));
    462     call_restricted_packet_assignment_no_alias(dst, lhs.lazyProduct(rhs), func);
    463   }
    464 
    465   template<typename Dst, typename LhsT, typename RhsT, typename Func, typename Scalar>
    466   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    467   void eval_dynamic_impl(Dst& dst, const LhsT& lhs, const RhsT& rhs, const Func &func, const Scalar& s, true_type)
    468   {
    469     call_restricted_packet_assignment_no_alias(dst, s * lhs.lazyProduct(rhs), func);
    470   }
    471 };
    472 
    473 // This specialization enforces the use of a coefficient-based evaluation strategy
    474 template<typename Lhs, typename Rhs>
    475 struct generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,LazyCoeffBasedProductMode>
    476   : generic_product_impl<Lhs,Rhs,DenseShape,DenseShape,CoeffBasedProductMode> {};
    477 
    478 // Case 2: Evaluate coeff by coeff
    479 //
    480 // This is mostly taken from CoeffBasedProduct.h
    481 // The main difference is that we add an extra argument to the etor_product_*_impl::run() function
    482 // for the inner dimension of the product, because evaluator object do not know their size.
    483 
    484 template<int Traversal, int UnrollingIndex, typename Lhs, typename Rhs, typename RetScalar>
    485 struct etor_product_coeff_impl;
    486 
    487 template<int StorageOrder, int UnrollingIndex, typename Lhs, typename Rhs, typename Packet, int LoadMode>
    488 struct etor_product_packet_impl;
    489 
    490 template<typename Lhs, typename Rhs, int ProductTag>
    491 struct product_evaluator<Product<Lhs, Rhs, LazyProduct>, ProductTag, DenseShape, DenseShape>
    492     : evaluator_base<Product<Lhs, Rhs, LazyProduct> >
    493 {
    494   typedef Product<Lhs, Rhs, LazyProduct> XprType;
    495   typedef typename XprType::Scalar Scalar;
    496   typedef typename XprType::CoeffReturnType CoeffReturnType;
    497 
    498   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    499   explicit product_evaluator(const XprType& xpr)
    500     : m_lhs(xpr.lhs()),
    501       m_rhs(xpr.rhs()),
    502       m_lhsImpl(m_lhs),     // FIXME the creation of the evaluator objects should result in a no-op, but check that!
    503       m_rhsImpl(m_rhs),     //       Moreover, they are only useful for the packet path, so we could completely disable them when not needed,
    504                             //       or perhaps declare them on the fly on the packet method... We have experiment to check what's best.
    505       m_innerDim(xpr.lhs().cols())
    506   {
    507     EIGEN_INTERNAL_CHECK_COST_VALUE(NumTraits<Scalar>::MulCost);
    508     EIGEN_INTERNAL_CHECK_COST_VALUE(NumTraits<Scalar>::AddCost);
    509     EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
    510 #if 0
    511     std::cerr << "LhsOuterStrideBytes=  " << LhsOuterStrideBytes << "\n";
    512     std::cerr << "RhsOuterStrideBytes=  " << RhsOuterStrideBytes << "\n";
    513     std::cerr << "LhsAlignment=         " << LhsAlignment << "\n";
    514     std::cerr << "RhsAlignment=         " << RhsAlignment << "\n";
    515     std::cerr << "CanVectorizeLhs=      " << CanVectorizeLhs << "\n";
    516     std::cerr << "CanVectorizeRhs=      " << CanVectorizeRhs << "\n";
    517     std::cerr << "CanVectorizeInner=    " << CanVectorizeInner << "\n";
    518     std::cerr << "EvalToRowMajor=       " << EvalToRowMajor << "\n";
    519     std::cerr << "Alignment=            " << Alignment << "\n";
    520     std::cerr << "Flags=                " << Flags << "\n";
    521 #endif
    522   }
    523 
    524   // Everything below here is taken from CoeffBasedProduct.h
    525 
    526   typedef typename internal::nested_eval<Lhs,Rhs::ColsAtCompileTime>::type LhsNested;
    527   typedef typename internal::nested_eval<Rhs,Lhs::RowsAtCompileTime>::type RhsNested;
    528 
    529   typedef typename internal::remove_all<LhsNested>::type LhsNestedCleaned;
    530   typedef typename internal::remove_all<RhsNested>::type RhsNestedCleaned;
    531 
    532   typedef evaluator<LhsNestedCleaned> LhsEtorType;
    533   typedef evaluator<RhsNestedCleaned> RhsEtorType;
    534 
    535   enum {
    536     RowsAtCompileTime = LhsNestedCleaned::RowsAtCompileTime,
    537     ColsAtCompileTime = RhsNestedCleaned::ColsAtCompileTime,
    538     InnerSize = EIGEN_SIZE_MIN_PREFER_FIXED(LhsNestedCleaned::ColsAtCompileTime, RhsNestedCleaned::RowsAtCompileTime),
    539     MaxRowsAtCompileTime = LhsNestedCleaned::MaxRowsAtCompileTime,
    540     MaxColsAtCompileTime = RhsNestedCleaned::MaxColsAtCompileTime
    541   };
    542 
    543   typedef typename find_best_packet<Scalar,RowsAtCompileTime>::type LhsVecPacketType;
    544   typedef typename find_best_packet<Scalar,ColsAtCompileTime>::type RhsVecPacketType;
    545 
    546   enum {
    547 
    548     LhsCoeffReadCost = LhsEtorType::CoeffReadCost,
    549     RhsCoeffReadCost = RhsEtorType::CoeffReadCost,
    550     CoeffReadCost = InnerSize==0 ? NumTraits<Scalar>::ReadCost
    551                   : InnerSize == Dynamic ? HugeCost
    552                     : InnerSize * (NumTraits<Scalar>::MulCost + int(LhsCoeffReadCost) + int(RhsCoeffReadCost))
    553                     + (InnerSize - 1) * NumTraits<Scalar>::AddCost,
    554 
    555     Unroll = CoeffReadCost <= EIGEN_UNROLLING_LIMIT,
    556 
    557     LhsFlags = LhsEtorType::Flags,
    558     RhsFlags = RhsEtorType::Flags,
    559 
    560     LhsRowMajor = LhsFlags & RowMajorBit,
    561     RhsRowMajor = RhsFlags & RowMajorBit,
    562 
    563     LhsVecPacketSize = unpacket_traits<LhsVecPacketType>::size,
    564     RhsVecPacketSize = unpacket_traits<RhsVecPacketType>::size,
    565 
    566     // Here, we don't care about alignment larger than the usable packet size.
    567     LhsAlignment = EIGEN_PLAIN_ENUM_MIN(LhsEtorType::Alignment,LhsVecPacketSize*int(sizeof(typename LhsNestedCleaned::Scalar))),
    568     RhsAlignment = EIGEN_PLAIN_ENUM_MIN(RhsEtorType::Alignment,RhsVecPacketSize*int(sizeof(typename RhsNestedCleaned::Scalar))),
    569 
    570     SameType = is_same<typename LhsNestedCleaned::Scalar,typename RhsNestedCleaned::Scalar>::value,
    571 
    572     CanVectorizeRhs = bool(RhsRowMajor) && (RhsFlags & PacketAccessBit) && (ColsAtCompileTime!=1),
    573     CanVectorizeLhs = (!LhsRowMajor) && (LhsFlags & PacketAccessBit) && (RowsAtCompileTime!=1),
    574 
    575     EvalToRowMajor = (MaxRowsAtCompileTime==1&&MaxColsAtCompileTime!=1) ? 1
    576                     : (MaxColsAtCompileTime==1&&MaxRowsAtCompileTime!=1) ? 0
    577                     : (bool(RhsRowMajor) && !CanVectorizeLhs),
    578 
    579     Flags = ((int(LhsFlags) | int(RhsFlags)) & HereditaryBits & ~RowMajorBit)
    580           | (EvalToRowMajor ? RowMajorBit : 0)
    581           // TODO enable vectorization for mixed types
    582           | (SameType && (CanVectorizeLhs || CanVectorizeRhs) ? PacketAccessBit : 0)
    583           | (XprType::IsVectorAtCompileTime ? LinearAccessBit : 0),
    584 
    585     LhsOuterStrideBytes = int(LhsNestedCleaned::OuterStrideAtCompileTime) * int(sizeof(typename LhsNestedCleaned::Scalar)),
    586     RhsOuterStrideBytes = int(RhsNestedCleaned::OuterStrideAtCompileTime) * int(sizeof(typename RhsNestedCleaned::Scalar)),
    587 
    588     Alignment = bool(CanVectorizeLhs) ? (LhsOuterStrideBytes<=0 || (int(LhsOuterStrideBytes) % EIGEN_PLAIN_ENUM_MAX(1,LhsAlignment))!=0 ? 0 : LhsAlignment)
    589               : bool(CanVectorizeRhs) ? (RhsOuterStrideBytes<=0 || (int(RhsOuterStrideBytes) % EIGEN_PLAIN_ENUM_MAX(1,RhsAlignment))!=0 ? 0 : RhsAlignment)
    590               : 0,
    591 
    592     /* CanVectorizeInner deserves special explanation. It does not affect the product flags. It is not used outside
    593      * of Product. If the Product itself is not a packet-access expression, there is still a chance that the inner
    594      * loop of the product might be vectorized. This is the meaning of CanVectorizeInner. Since it doesn't affect
    595      * the Flags, it is safe to make this value depend on ActualPacketAccessBit, that doesn't affect the ABI.
    596      */
    597     CanVectorizeInner =    SameType
    598                         && LhsRowMajor
    599                         && (!RhsRowMajor)
    600                         && (int(LhsFlags) & int(RhsFlags) & ActualPacketAccessBit)
    601                         && (int(InnerSize) % packet_traits<Scalar>::size == 0)
    602   };
    603 
    604   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const CoeffReturnType coeff(Index row, Index col) const
    605   {
    606     return (m_lhs.row(row).transpose().cwiseProduct( m_rhs.col(col) )).sum();
    607   }
    608 
    609   /* Allow index-based non-packet access. It is impossible though to allow index-based packed access,
    610    * which is why we don't set the LinearAccessBit.
    611    * TODO: this seems possible when the result is a vector
    612    */
    613   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    614   const CoeffReturnType coeff(Index index) const
    615   {
    616     const Index row = (RowsAtCompileTime == 1 || MaxRowsAtCompileTime==1) ? 0 : index;
    617     const Index col = (RowsAtCompileTime == 1 || MaxRowsAtCompileTime==1) ? index : 0;
    618     return (m_lhs.row(row).transpose().cwiseProduct( m_rhs.col(col) )).sum();
    619   }
    620 
    621   template<int LoadMode, typename PacketType>
    622   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    623   const PacketType packet(Index row, Index col) const
    624   {
    625     PacketType res;
    626     typedef etor_product_packet_impl<bool(int(Flags)&RowMajorBit) ? RowMajor : ColMajor,
    627                                      Unroll ? int(InnerSize) : Dynamic,
    628                                      LhsEtorType, RhsEtorType, PacketType, LoadMode> PacketImpl;
    629     PacketImpl::run(row, col, m_lhsImpl, m_rhsImpl, m_innerDim, res);
    630     return res;
    631   }
    632 
    633   template<int LoadMode, typename PacketType>
    634   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    635   const PacketType packet(Index index) const
    636   {
    637     const Index row = (RowsAtCompileTime == 1 || MaxRowsAtCompileTime==1) ? 0 : index;
    638     const Index col = (RowsAtCompileTime == 1 || MaxRowsAtCompileTime==1) ? index : 0;
    639     return packet<LoadMode,PacketType>(row,col);
    640   }
    641 
    642 protected:
    643   typename internal::add_const_on_value_type<LhsNested>::type m_lhs;
    644   typename internal::add_const_on_value_type<RhsNested>::type m_rhs;
    645 
    646   LhsEtorType m_lhsImpl;
    647   RhsEtorType m_rhsImpl;
    648 
    649   // TODO: Get rid of m_innerDim if known at compile time
    650   Index m_innerDim;
    651 };
    652 
    653 template<typename Lhs, typename Rhs>
    654 struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, LazyCoeffBasedProductMode, DenseShape, DenseShape>
    655   : product_evaluator<Product<Lhs, Rhs, LazyProduct>, CoeffBasedProductMode, DenseShape, DenseShape>
    656 {
    657   typedef Product<Lhs, Rhs, DefaultProduct> XprType;
    658   typedef Product<Lhs, Rhs, LazyProduct> BaseProduct;
    659   typedef product_evaluator<BaseProduct, CoeffBasedProductMode, DenseShape, DenseShape> Base;
    660   enum {
    661     Flags = Base::Flags | EvalBeforeNestingBit
    662   };
    663   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
    664   explicit product_evaluator(const XprType& xpr)
    665     : Base(BaseProduct(xpr.lhs(),xpr.rhs()))
    666   {}
    667 };
    668 
    669 /****************************************
    670 *** Coeff based product, Packet path  ***
    671 ****************************************/
    672 
    673 template<int UnrollingIndex, typename Lhs, typename Rhs, typename Packet, int LoadMode>
    674 struct etor_product_packet_impl<RowMajor, UnrollingIndex, Lhs, Rhs, Packet, LoadMode>
    675 {
    676   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index innerDim, Packet &res)
    677   {
    678     etor_product_packet_impl<RowMajor, UnrollingIndex-1, Lhs, Rhs, Packet, LoadMode>::run(row, col, lhs, rhs, innerDim, res);
    679     res =  pmadd(pset1<Packet>(lhs.coeff(row, Index(UnrollingIndex-1))), rhs.template packet<LoadMode,Packet>(Index(UnrollingIndex-1), col), res);
    680   }
    681 };
    682 
    683 template<int UnrollingIndex, typename Lhs, typename Rhs, typename Packet, int LoadMode>
    684 struct etor_product_packet_impl<ColMajor, UnrollingIndex, Lhs, Rhs, Packet, LoadMode>
    685 {
    686   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index innerDim, Packet &res)
    687   {
    688     etor_product_packet_impl<ColMajor, UnrollingIndex-1, Lhs, Rhs, Packet, LoadMode>::run(row, col, lhs, rhs, innerDim, res);
    689     res =  pmadd(lhs.template packet<LoadMode,Packet>(row, Index(UnrollingIndex-1)), pset1<Packet>(rhs.coeff(Index(UnrollingIndex-1), col)), res);
    690   }
    691 };
    692 
    693 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    694 struct etor_product_packet_impl<RowMajor, 1, Lhs, Rhs, Packet, LoadMode>
    695 {
    696   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index /*innerDim*/, Packet &res)
    697   {
    698     res = pmul(pset1<Packet>(lhs.coeff(row, Index(0))),rhs.template packet<LoadMode,Packet>(Index(0), col));
    699   }
    700 };
    701 
    702 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    703 struct etor_product_packet_impl<ColMajor, 1, Lhs, Rhs, Packet, LoadMode>
    704 {
    705   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index /*innerDim*/, Packet &res)
    706   {
    707     res = pmul(lhs.template packet<LoadMode,Packet>(row, Index(0)), pset1<Packet>(rhs.coeff(Index(0), col)));
    708   }
    709 };
    710 
    711 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    712 struct etor_product_packet_impl<RowMajor, 0, Lhs, Rhs, Packet, LoadMode>
    713 {
    714   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index /*row*/, Index /*col*/, const Lhs& /*lhs*/, const Rhs& /*rhs*/, Index /*innerDim*/, Packet &res)
    715   {
    716     res = pset1<Packet>(typename unpacket_traits<Packet>::type(0));
    717   }
    718 };
    719 
    720 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    721 struct etor_product_packet_impl<ColMajor, 0, Lhs, Rhs, Packet, LoadMode>
    722 {
    723   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index /*row*/, Index /*col*/, const Lhs& /*lhs*/, const Rhs& /*rhs*/, Index /*innerDim*/, Packet &res)
    724   {
    725     res = pset1<Packet>(typename unpacket_traits<Packet>::type(0));
    726   }
    727 };
    728 
    729 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    730 struct etor_product_packet_impl<RowMajor, Dynamic, Lhs, Rhs, Packet, LoadMode>
    731 {
    732   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index innerDim, Packet& res)
    733   {
    734     res = pset1<Packet>(typename unpacket_traits<Packet>::type(0));
    735     for(Index i = 0; i < innerDim; ++i)
    736       res =  pmadd(pset1<Packet>(lhs.coeff(row, i)), rhs.template packet<LoadMode,Packet>(i, col), res);
    737   }
    738 };
    739 
    740 template<typename Lhs, typename Rhs, typename Packet, int LoadMode>
    741 struct etor_product_packet_impl<ColMajor, Dynamic, Lhs, Rhs, Packet, LoadMode>
    742 {
    743   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Index row, Index col, const Lhs& lhs, const Rhs& rhs, Index innerDim, Packet& res)
    744   {
    745     res = pset1<Packet>(typename unpacket_traits<Packet>::type(0));
    746     for(Index i = 0; i < innerDim; ++i)
    747       res =  pmadd(lhs.template packet<LoadMode,Packet>(row, i), pset1<Packet>(rhs.coeff(i, col)), res);
    748   }
    749 };
    750 
    751 
    752 /***************************************************************************
    753 * Triangular products
    754 ***************************************************************************/
    755 template<int Mode, bool LhsIsTriangular,
    756          typename Lhs, bool LhsIsVector,
    757          typename Rhs, bool RhsIsVector>
    758 struct triangular_product_impl;
    759 
    760 template<typename Lhs, typename Rhs, int ProductTag>
    761 struct generic_product_impl<Lhs,Rhs,TriangularShape,DenseShape,ProductTag>
    762   : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,TriangularShape,DenseShape,ProductTag> >
    763 {
    764   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    765 
    766   template<typename Dest>
    767   static void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    768   {
    769     triangular_product_impl<Lhs::Mode,true,typename Lhs::MatrixType,false,Rhs, Rhs::ColsAtCompileTime==1>
    770         ::run(dst, lhs.nestedExpression(), rhs, alpha);
    771   }
    772 };
    773 
    774 template<typename Lhs, typename Rhs, int ProductTag>
    775 struct generic_product_impl<Lhs,Rhs,DenseShape,TriangularShape,ProductTag>
    776 : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,DenseShape,TriangularShape,ProductTag> >
    777 {
    778   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    779 
    780   template<typename Dest>
    781   static void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    782   {
    783     triangular_product_impl<Rhs::Mode,false,Lhs,Lhs::RowsAtCompileTime==1, typename Rhs::MatrixType, false>::run(dst, lhs, rhs.nestedExpression(), alpha);
    784   }
    785 };
    786 
    787 
    788 /***************************************************************************
    789 * SelfAdjoint products
    790 ***************************************************************************/
    791 template <typename Lhs, int LhsMode, bool LhsIsVector,
    792           typename Rhs, int RhsMode, bool RhsIsVector>
    793 struct selfadjoint_product_impl;
    794 
    795 template<typename Lhs, typename Rhs, int ProductTag>
    796 struct generic_product_impl<Lhs,Rhs,SelfAdjointShape,DenseShape,ProductTag>
    797   : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,SelfAdjointShape,DenseShape,ProductTag> >
    798 {
    799   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    800 
    801   template<typename Dest>
    802   static EIGEN_DEVICE_FUNC
    803   void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    804   {
    805     selfadjoint_product_impl<typename Lhs::MatrixType,Lhs::Mode,false,Rhs,0,Rhs::IsVectorAtCompileTime>::run(dst, lhs.nestedExpression(), rhs, alpha);
    806   }
    807 };
    808 
    809 template<typename Lhs, typename Rhs, int ProductTag>
    810 struct generic_product_impl<Lhs,Rhs,DenseShape,SelfAdjointShape,ProductTag>
    811 : generic_product_impl_base<Lhs,Rhs,generic_product_impl<Lhs,Rhs,DenseShape,SelfAdjointShape,ProductTag> >
    812 {
    813   typedef typename Product<Lhs,Rhs>::Scalar Scalar;
    814 
    815   template<typename Dest>
    816   static void scaleAndAddTo(Dest& dst, const Lhs& lhs, const Rhs& rhs, const Scalar& alpha)
    817   {
    818     selfadjoint_product_impl<Lhs,0,Lhs::IsVectorAtCompileTime,typename Rhs::MatrixType,Rhs::Mode,false>::run(dst, lhs, rhs.nestedExpression(), alpha);
    819   }
    820 };
    821 
    822 
    823 /***************************************************************************
    824 * Diagonal products
    825 ***************************************************************************/
    826 
    827 template<typename MatrixType, typename DiagonalType, typename Derived, int ProductOrder>
    828 struct diagonal_product_evaluator_base
    829   : evaluator_base<Derived>
    830 {
    831    typedef typename ScalarBinaryOpTraits<typename MatrixType::Scalar, typename DiagonalType::Scalar>::ReturnType Scalar;
    832 public:
    833   enum {
    834     CoeffReadCost = int(NumTraits<Scalar>::MulCost) + int(evaluator<MatrixType>::CoeffReadCost) + int(evaluator<DiagonalType>::CoeffReadCost),
    835 
    836     MatrixFlags = evaluator<MatrixType>::Flags,
    837     DiagFlags = evaluator<DiagonalType>::Flags,
    838 
    839     _StorageOrder = (Derived::MaxRowsAtCompileTime==1 && Derived::MaxColsAtCompileTime!=1) ? RowMajor
    840                   : (Derived::MaxColsAtCompileTime==1 && Derived::MaxRowsAtCompileTime!=1) ? ColMajor
    841                   : MatrixFlags & RowMajorBit ? RowMajor : ColMajor,
    842     _SameStorageOrder = _StorageOrder == (MatrixFlags & RowMajorBit ? RowMajor : ColMajor),
    843 
    844     _ScalarAccessOnDiag =  !((int(_StorageOrder) == ColMajor && int(ProductOrder) == OnTheLeft)
    845                            ||(int(_StorageOrder) == RowMajor && int(ProductOrder) == OnTheRight)),
    846     _SameTypes = is_same<typename MatrixType::Scalar, typename DiagonalType::Scalar>::value,
    847     // FIXME currently we need same types, but in the future the next rule should be the one
    848     //_Vectorizable = bool(int(MatrixFlags)&PacketAccessBit) && ((!_PacketOnDiag) || (_SameTypes && bool(int(DiagFlags)&PacketAccessBit))),
    849     _Vectorizable =   bool(int(MatrixFlags)&PacketAccessBit)
    850                   &&  _SameTypes
    851                   && (_SameStorageOrder || (MatrixFlags&LinearAccessBit)==LinearAccessBit)
    852                   && (_ScalarAccessOnDiag || (bool(int(DiagFlags)&PacketAccessBit))),
    853     _LinearAccessMask = (MatrixType::RowsAtCompileTime==1 || MatrixType::ColsAtCompileTime==1) ? LinearAccessBit : 0,
    854     Flags = ((HereditaryBits|_LinearAccessMask) & (unsigned int)(MatrixFlags)) | (_Vectorizable ? PacketAccessBit : 0),
    855     Alignment = evaluator<MatrixType>::Alignment,
    856 
    857     AsScalarProduct =     (DiagonalType::SizeAtCompileTime==1)
    858                       ||  (DiagonalType::SizeAtCompileTime==Dynamic && MatrixType::RowsAtCompileTime==1 && ProductOrder==OnTheLeft)
    859                       ||  (DiagonalType::SizeAtCompileTime==Dynamic && MatrixType::ColsAtCompileTime==1 && ProductOrder==OnTheRight)
    860   };
    861 
    862   EIGEN_DEVICE_FUNC diagonal_product_evaluator_base(const MatrixType &mat, const DiagonalType &diag)
    863     : m_diagImpl(diag), m_matImpl(mat)
    864   {
    865     EIGEN_INTERNAL_CHECK_COST_VALUE(NumTraits<Scalar>::MulCost);
    866     EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
    867   }
    868 
    869   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar coeff(Index idx) const
    870   {
    871     if(AsScalarProduct)
    872       return m_diagImpl.coeff(0) * m_matImpl.coeff(idx);
    873     else
    874       return m_diagImpl.coeff(idx) * m_matImpl.coeff(idx);
    875   }
    876 
    877 protected:
    878   template<int LoadMode,typename PacketType>
    879   EIGEN_STRONG_INLINE PacketType packet_impl(Index row, Index col, Index id, internal::true_type) const
    880   {
    881     return internal::pmul(m_matImpl.template packet<LoadMode,PacketType>(row, col),
    882                           internal::pset1<PacketType>(m_diagImpl.coeff(id)));
    883   }
    884 
    885   template<int LoadMode,typename PacketType>
    886   EIGEN_STRONG_INLINE PacketType packet_impl(Index row, Index col, Index id, internal::false_type) const
    887   {
    888     enum {
    889       InnerSize = (MatrixType::Flags & RowMajorBit) ? MatrixType::ColsAtCompileTime : MatrixType::RowsAtCompileTime,
    890       DiagonalPacketLoadMode = EIGEN_PLAIN_ENUM_MIN(LoadMode,((InnerSize%16) == 0) ? int(Aligned16) : int(evaluator<DiagonalType>::Alignment)) // FIXME hardcoded 16!!
    891     };
    892     return internal::pmul(m_matImpl.template packet<LoadMode,PacketType>(row, col),
    893                           m_diagImpl.template packet<DiagonalPacketLoadMode,PacketType>(id));
    894   }
    895 
    896   evaluator<DiagonalType> m_diagImpl;
    897   evaluator<MatrixType>   m_matImpl;
    898 };
    899 
    900 // diagonal * dense
    901 template<typename Lhs, typename Rhs, int ProductKind, int ProductTag>
    902 struct product_evaluator<Product<Lhs, Rhs, ProductKind>, ProductTag, DiagonalShape, DenseShape>
    903   : diagonal_product_evaluator_base<Rhs, typename Lhs::DiagonalVectorType, Product<Lhs, Rhs, LazyProduct>, OnTheLeft>
    904 {
    905   typedef diagonal_product_evaluator_base<Rhs, typename Lhs::DiagonalVectorType, Product<Lhs, Rhs, LazyProduct>, OnTheLeft> Base;
    906   using Base::m_diagImpl;
    907   using Base::m_matImpl;
    908   using Base::coeff;
    909   typedef typename Base::Scalar Scalar;
    910 
    911   typedef Product<Lhs, Rhs, ProductKind> XprType;
    912   typedef typename XprType::PlainObject PlainObject;
    913   typedef typename Lhs::DiagonalVectorType DiagonalType;
    914 
    915 
    916   enum { StorageOrder = Base::_StorageOrder };
    917 
    918   EIGEN_DEVICE_FUNC explicit product_evaluator(const XprType& xpr)
    919     : Base(xpr.rhs(), xpr.lhs().diagonal())
    920   {
    921   }
    922 
    923   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar coeff(Index row, Index col) const
    924   {
    925     return m_diagImpl.coeff(row) * m_matImpl.coeff(row, col);
    926   }
    927 
    928 #ifndef EIGEN_GPUCC
    929   template<int LoadMode,typename PacketType>
    930   EIGEN_STRONG_INLINE PacketType packet(Index row, Index col) const
    931   {
    932     // FIXME: NVCC used to complain about the template keyword, but we have to check whether this is still the case.
    933     // See also similar calls below.
    934     return this->template packet_impl<LoadMode,PacketType>(row,col, row,
    935                                  typename internal::conditional<int(StorageOrder)==RowMajor, internal::true_type, internal::false_type>::type());
    936   }
    937 
    938   template<int LoadMode,typename PacketType>
    939   EIGEN_STRONG_INLINE PacketType packet(Index idx) const
    940   {
    941     return packet<LoadMode,PacketType>(int(StorageOrder)==ColMajor?idx:0,int(StorageOrder)==ColMajor?0:idx);
    942   }
    943 #endif
    944 };
    945 
    946 // dense * diagonal
    947 template<typename Lhs, typename Rhs, int ProductKind, int ProductTag>
    948 struct product_evaluator<Product<Lhs, Rhs, ProductKind>, ProductTag, DenseShape, DiagonalShape>
    949   : diagonal_product_evaluator_base<Lhs, typename Rhs::DiagonalVectorType, Product<Lhs, Rhs, LazyProduct>, OnTheRight>
    950 {
    951   typedef diagonal_product_evaluator_base<Lhs, typename Rhs::DiagonalVectorType, Product<Lhs, Rhs, LazyProduct>, OnTheRight> Base;
    952   using Base::m_diagImpl;
    953   using Base::m_matImpl;
    954   using Base::coeff;
    955   typedef typename Base::Scalar Scalar;
    956 
    957   typedef Product<Lhs, Rhs, ProductKind> XprType;
    958   typedef typename XprType::PlainObject PlainObject;
    959 
    960   enum { StorageOrder = Base::_StorageOrder };
    961 
    962   EIGEN_DEVICE_FUNC explicit product_evaluator(const XprType& xpr)
    963     : Base(xpr.lhs(), xpr.rhs().diagonal())
    964   {
    965   }
    966 
    967   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar coeff(Index row, Index col) const
    968   {
    969     return m_matImpl.coeff(row, col) * m_diagImpl.coeff(col);
    970   }
    971 
    972 #ifndef EIGEN_GPUCC
    973   template<int LoadMode,typename PacketType>
    974   EIGEN_STRONG_INLINE PacketType packet(Index row, Index col) const
    975   {
    976     return this->template packet_impl<LoadMode,PacketType>(row,col, col,
    977                                  typename internal::conditional<int(StorageOrder)==ColMajor, internal::true_type, internal::false_type>::type());
    978   }
    979 
    980   template<int LoadMode,typename PacketType>
    981   EIGEN_STRONG_INLINE PacketType packet(Index idx) const
    982   {
    983     return packet<LoadMode,PacketType>(int(StorageOrder)==ColMajor?idx:0,int(StorageOrder)==ColMajor?0:idx);
    984   }
    985 #endif
    986 };
    987 
    988 /***************************************************************************
    989 * Products with permutation matrices
    990 ***************************************************************************/
    991 
    992 /** \internal
    993   * \class permutation_matrix_product
    994   * Internal helper class implementing the product between a permutation matrix and a matrix.
    995   * This class is specialized for DenseShape below and for SparseShape in SparseCore/SparsePermutation.h
    996   */
    997 template<typename ExpressionType, int Side, bool Transposed, typename ExpressionShape>
    998 struct permutation_matrix_product;
    999 
   1000 template<typename ExpressionType, int Side, bool Transposed>
   1001 struct permutation_matrix_product<ExpressionType, Side, Transposed, DenseShape>
   1002 {
   1003     typedef typename nested_eval<ExpressionType, 1>::type MatrixType;
   1004     typedef typename remove_all<MatrixType>::type MatrixTypeCleaned;
   1005 
   1006     template<typename Dest, typename PermutationType>
   1007     static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Dest& dst, const PermutationType& perm, const ExpressionType& xpr)
   1008     {
   1009       MatrixType mat(xpr);
   1010       const Index n = Side==OnTheLeft ? mat.rows() : mat.cols();
   1011       // FIXME we need an is_same for expression that is not sensitive to constness. For instance
   1012       // is_same_xpr<Block<const Matrix>, Block<Matrix> >::value should be true.
   1013       //if(is_same<MatrixTypeCleaned,Dest>::value && extract_data(dst) == extract_data(mat))
   1014       if(is_same_dense(dst, mat))
   1015       {
   1016         // apply the permutation inplace
   1017         Matrix<bool,PermutationType::RowsAtCompileTime,1,0,PermutationType::MaxRowsAtCompileTime> mask(perm.size());
   1018         mask.fill(false);
   1019         Index r = 0;
   1020         while(r < perm.size())
   1021         {
   1022           // search for the next seed
   1023           while(r<perm.size() && mask[r]) r++;
   1024           if(r>=perm.size())
   1025             break;
   1026           // we got one, let's follow it until we are back to the seed
   1027           Index k0 = r++;
   1028           Index kPrev = k0;
   1029           mask.coeffRef(k0) = true;
   1030           for(Index k=perm.indices().coeff(k0); k!=k0; k=perm.indices().coeff(k))
   1031           {
   1032                   Block<Dest, Side==OnTheLeft ? 1 : Dest::RowsAtCompileTime, Side==OnTheRight ? 1 : Dest::ColsAtCompileTime>(dst, k)
   1033             .swap(Block<Dest, Side==OnTheLeft ? 1 : Dest::RowsAtCompileTime, Side==OnTheRight ? 1 : Dest::ColsAtCompileTime>
   1034                        (dst,((Side==OnTheLeft) ^ Transposed) ? k0 : kPrev));
   1035 
   1036             mask.coeffRef(k) = true;
   1037             kPrev = k;
   1038           }
   1039         }
   1040       }
   1041       else
   1042       {
   1043         for(Index i = 0; i < n; ++i)
   1044         {
   1045           Block<Dest, Side==OnTheLeft ? 1 : Dest::RowsAtCompileTime, Side==OnTheRight ? 1 : Dest::ColsAtCompileTime>
   1046                (dst, ((Side==OnTheLeft) ^ Transposed) ? perm.indices().coeff(i) : i)
   1047 
   1048           =
   1049 
   1050           Block<const MatrixTypeCleaned,Side==OnTheLeft ? 1 : MatrixTypeCleaned::RowsAtCompileTime,Side==OnTheRight ? 1 : MatrixTypeCleaned::ColsAtCompileTime>
   1051                (mat, ((Side==OnTheRight) ^ Transposed) ? perm.indices().coeff(i) : i);
   1052         }
   1053       }
   1054     }
   1055 };
   1056 
   1057 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1058 struct generic_product_impl<Lhs, Rhs, PermutationShape, MatrixShape, ProductTag>
   1059 {
   1060   template<typename Dest>
   1061   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs)
   1062   {
   1063     permutation_matrix_product<Rhs, OnTheLeft, false, MatrixShape>::run(dst, lhs, rhs);
   1064   }
   1065 };
   1066 
   1067 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1068 struct generic_product_impl<Lhs, Rhs, MatrixShape, PermutationShape, ProductTag>
   1069 {
   1070   template<typename Dest>
   1071   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs)
   1072   {
   1073     permutation_matrix_product<Lhs, OnTheRight, false, MatrixShape>::run(dst, rhs, lhs);
   1074   }
   1075 };
   1076 
   1077 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1078 struct generic_product_impl<Inverse<Lhs>, Rhs, PermutationShape, MatrixShape, ProductTag>
   1079 {
   1080   template<typename Dest>
   1081   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Inverse<Lhs>& lhs, const Rhs& rhs)
   1082   {
   1083     permutation_matrix_product<Rhs, OnTheLeft, true, MatrixShape>::run(dst, lhs.nestedExpression(), rhs);
   1084   }
   1085 };
   1086 
   1087 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1088 struct generic_product_impl<Lhs, Inverse<Rhs>, MatrixShape, PermutationShape, ProductTag>
   1089 {
   1090   template<typename Dest>
   1091   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Inverse<Rhs>& rhs)
   1092   {
   1093     permutation_matrix_product<Lhs, OnTheRight, true, MatrixShape>::run(dst, rhs.nestedExpression(), lhs);
   1094   }
   1095 };
   1096 
   1097 
   1098 /***************************************************************************
   1099 * Products with transpositions matrices
   1100 ***************************************************************************/
   1101 
   1102 // FIXME could we unify Transpositions and Permutation into a single "shape"??
   1103 
   1104 /** \internal
   1105   * \class transposition_matrix_product
   1106   * Internal helper class implementing the product between a permutation matrix and a matrix.
   1107   */
   1108 template<typename ExpressionType, int Side, bool Transposed, typename ExpressionShape>
   1109 struct transposition_matrix_product
   1110 {
   1111   typedef typename nested_eval<ExpressionType, 1>::type MatrixType;
   1112   typedef typename remove_all<MatrixType>::type MatrixTypeCleaned;
   1113 
   1114   template<typename Dest, typename TranspositionType>
   1115   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void run(Dest& dst, const TranspositionType& tr, const ExpressionType& xpr)
   1116   {
   1117     MatrixType mat(xpr);
   1118     typedef typename TranspositionType::StorageIndex StorageIndex;
   1119     const Index size = tr.size();
   1120     StorageIndex j = 0;
   1121 
   1122     if(!is_same_dense(dst,mat))
   1123       dst = mat;
   1124 
   1125     for(Index k=(Transposed?size-1:0) ; Transposed?k>=0:k<size ; Transposed?--k:++k)
   1126       if(Index(j=tr.coeff(k))!=k)
   1127       {
   1128         if(Side==OnTheLeft)        dst.row(k).swap(dst.row(j));
   1129         else if(Side==OnTheRight)  dst.col(k).swap(dst.col(j));
   1130       }
   1131   }
   1132 };
   1133 
   1134 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1135 struct generic_product_impl<Lhs, Rhs, TranspositionsShape, MatrixShape, ProductTag>
   1136 {
   1137   template<typename Dest>
   1138   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs)
   1139   {
   1140     transposition_matrix_product<Rhs, OnTheLeft, false, MatrixShape>::run(dst, lhs, rhs);
   1141   }
   1142 };
   1143 
   1144 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1145 struct generic_product_impl<Lhs, Rhs, MatrixShape, TranspositionsShape, ProductTag>
   1146 {
   1147   template<typename Dest>
   1148   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Rhs& rhs)
   1149   {
   1150     transposition_matrix_product<Lhs, OnTheRight, false, MatrixShape>::run(dst, rhs, lhs);
   1151   }
   1152 };
   1153 
   1154 
   1155 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1156 struct generic_product_impl<Transpose<Lhs>, Rhs, TranspositionsShape, MatrixShape, ProductTag>
   1157 {
   1158   template<typename Dest>
   1159   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Transpose<Lhs>& lhs, const Rhs& rhs)
   1160   {
   1161     transposition_matrix_product<Rhs, OnTheLeft, true, MatrixShape>::run(dst, lhs.nestedExpression(), rhs);
   1162   }
   1163 };
   1164 
   1165 template<typename Lhs, typename Rhs, int ProductTag, typename MatrixShape>
   1166 struct generic_product_impl<Lhs, Transpose<Rhs>, MatrixShape, TranspositionsShape, ProductTag>
   1167 {
   1168   template<typename Dest>
   1169   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalTo(Dest& dst, const Lhs& lhs, const Transpose<Rhs>& rhs)
   1170   {
   1171     transposition_matrix_product<Lhs, OnTheRight, true, MatrixShape>::run(dst, rhs.nestedExpression(), lhs);
   1172   }
   1173 };
   1174 
   1175 } // end namespace internal
   1176 
   1177 } // end namespace Eigen
   1178 
   1179 #endif // EIGEN_PRODUCT_EVALUATORS_H