1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008-2011 Gael Guennebaud <gael.guennebaud@inria.fr>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9 
10 #ifndef EIGEN_PRODUCT_H
11 #define EIGEN_PRODUCT_H
12 
13 namespace Eigen {
14 
15 template<typename Lhs, typename Rhs, int Option, typename StorageKind> class ProductImpl;
16 
17 namespace internal {
18 
19 template<typename Lhs, typename Rhs, int Option>
20 struct traits<Product<Lhs, Rhs, Option> >
21 {
22   typedef typename remove_all<Lhs>::type LhsCleaned;
23   typedef typename remove_all<Rhs>::type RhsCleaned;
24   typedef traits<LhsCleaned> LhsTraits;
25   typedef traits<RhsCleaned> RhsTraits;
26 
27   typedef MatrixXpr XprKind;
28 
29   typedef typename ScalarBinaryOpTraits<typename traits<LhsCleaned>::Scalar, typename traits<RhsCleaned>::Scalar>::ReturnType Scalar;
30   typedef typename product_promote_storage_type<typename LhsTraits::StorageKind,
31                                                 typename RhsTraits::StorageKind,
32                                                 internal::product_type<Lhs,Rhs>::ret>::ret StorageKind;
33   typedef typename promote_index_type<typename LhsTraits::StorageIndex,
34                                       typename RhsTraits::StorageIndex>::type StorageIndex;
35 
36   enum {
37     RowsAtCompileTime    = LhsTraits::RowsAtCompileTime,
38     ColsAtCompileTime    = RhsTraits::ColsAtCompileTime,
39     MaxRowsAtCompileTime = LhsTraits::MaxRowsAtCompileTime,
40     MaxColsAtCompileTime = RhsTraits::MaxColsAtCompileTime,
41 
42     // FIXME: only needed by GeneralMatrixMatrixTriangular
43     InnerSize = EIGEN_SIZE_MIN_PREFER_FIXED(LhsTraits::ColsAtCompileTime, RhsTraits::RowsAtCompileTime),
44 
45     // The storage order is somewhat arbitrary here. The correct one will be determined through the evaluator.
46     Flags = (MaxRowsAtCompileTime==1 && MaxColsAtCompileTime!=1) ? RowMajorBit
47           : (MaxColsAtCompileTime==1 && MaxRowsAtCompileTime!=1) ? 0
48           : (   ((LhsTraits::Flags&NoPreferredStorageOrderBit) && (RhsTraits::Flags&RowMajorBit))
49              || ((RhsTraits::Flags&NoPreferredStorageOrderBit) && (LhsTraits::Flags&RowMajorBit)) ) ? RowMajorBit
50           : NoPreferredStorageOrderBit
51   };
52 };
53 
54 } // end namespace internal
55 
56 /** \class Product
57   * \ingroup Core_Module
58   *
59   * \brief Expression of the product of two arbitrary matrices or vectors
60   *
61   * \tparam _Lhs the type of the left-hand side expression
62   * \tparam _Rhs the type of the right-hand side expression
63   *
64   * This class represents an expression of the product of two arbitrary matrices.
65   *
66   * The other template parameters are:
67   * \tparam Option     can be DefaultProduct, AliasFreeProduct, or LazyProduct
68   *
69   */
70 template<typename _Lhs, typename _Rhs, int Option>
71 class Product : public ProductImpl<_Lhs,_Rhs,Option,
72                                    typename internal::product_promote_storage_type<typename internal::traits<_Lhs>::StorageKind,
73                                                                                    typename internal::traits<_Rhs>::StorageKind,
74                                                                                    internal::product_type<_Lhs,_Rhs>::ret>::ret>
75 {
76   public:
77 
78     typedef _Lhs Lhs;
79     typedef _Rhs Rhs;
80 
81     typedef typename ProductImpl<
82         Lhs, Rhs, Option,
83         typename internal::product_promote_storage_type<typename internal::traits<Lhs>::StorageKind,
84                                                         typename internal::traits<Rhs>::StorageKind,
85                                                         internal::product_type<Lhs,Rhs>::ret>::ret>::Base Base;
86     EIGEN_GENERIC_PUBLIC_INTERFACE(Product)
87 
88     typedef typename internal::ref_selector<Lhs>::type LhsNested;
89     typedef typename internal::ref_selector<Rhs>::type RhsNested;
90     typedef typename internal::remove_all<LhsNested>::type LhsNestedCleaned;
91     typedef typename internal::remove_all<RhsNested>::type RhsNestedCleaned;
92 
93     EIGEN_DEVICE_FUNC Product(const Lhs& lhs, const Rhs& rhs) : m_lhs(lhs), m_rhs(rhs)
94     {
95       eigen_assert(lhs.cols() == rhs.rows()
96         && "invalid matrix product"
97         && "if you wanted a coeff-wise or a dot product use the respective explicit functions");
98     }
99 
100     EIGEN_DEVICE_FUNC inline Index rows() const { return m_lhs.rows(); }
101     EIGEN_DEVICE_FUNC inline Index cols() const { return m_rhs.cols(); }
102 
103     EIGEN_DEVICE_FUNC const LhsNestedCleaned& lhs() const { return m_lhs; }
104     EIGEN_DEVICE_FUNC const RhsNestedCleaned& rhs() const { return m_rhs; }
105 
106   protected:
107 
108     LhsNested m_lhs;
109     RhsNested m_rhs;
110 };
111 
112 namespace internal {
113 
114 template<typename Lhs, typename Rhs, int Option, int ProductTag = internal::product_type<Lhs,Rhs>::ret>
115 class dense_product_base
116  : public internal::dense_xpr_base<Product<Lhs,Rhs,Option> >::type
117 {};
118 
119 /** Convertion to scalar for inner-products */
120 template<typename Lhs, typename Rhs, int Option>
121 class dense_product_base<Lhs, Rhs, Option, InnerProduct>
122  : public internal::dense_xpr_base<Product<Lhs,Rhs,Option> >::type
123 {
124   typedef Product<Lhs,Rhs,Option> ProductXpr;
125   typedef typename internal::dense_xpr_base<ProductXpr>::type Base;
126 public:
127   using Base::derived;
128   typedef typename Base::Scalar Scalar;
129 
130   operator const Scalar() const
131   {
132     return internal::evaluator<ProductXpr>(derived()).coeff(0,0);
133   }
134 };
135 
136 } // namespace internal
137 
138 // Generic API dispatcher
139 template<typename Lhs, typename Rhs, int Option, typename StorageKind>
140 class ProductImpl : public internal::generic_xpr_base<Product<Lhs,Rhs,Option>, MatrixXpr, StorageKind>::type
141 {
142   public:
143     typedef typename internal::generic_xpr_base<Product<Lhs,Rhs,Option>, MatrixXpr, StorageKind>::type Base;
144 };
145 
146 template<typename Lhs, typename Rhs, int Option>
147 class ProductImpl<Lhs,Rhs,Option,Dense>
148   : public internal::dense_product_base<Lhs,Rhs,Option>
149 {
150     typedef Product<Lhs, Rhs, Option> Derived;
151 
152   public:
153 
154     typedef typename internal::dense_product_base<Lhs, Rhs, Option> Base;
155     EIGEN_DENSE_PUBLIC_INTERFACE(Derived)
156   protected:
157     enum {
158       IsOneByOne = (RowsAtCompileTime == 1 || RowsAtCompileTime == Dynamic) &&
159                    (ColsAtCompileTime == 1 || ColsAtCompileTime == Dynamic),
160       EnableCoeff = IsOneByOne || Option==LazyProduct
161     };
162 
163   public:
164 
165     EIGEN_DEVICE_FUNC Scalar coeff(Index row, Index col) const
166     {
167       EIGEN_STATIC_ASSERT(EnableCoeff, THIS_METHOD_IS_ONLY_FOR_INNER_OR_LAZY_PRODUCTS);
168       eigen_assert( (Option==LazyProduct) || (this->rows() == 1 && this->cols() == 1) );
169 
170       return internal::evaluator<Derived>(derived()).coeff(row,col);
171     }
172 
173     EIGEN_DEVICE_FUNC Scalar coeff(Index i) const
174     {
175       EIGEN_STATIC_ASSERT(EnableCoeff, THIS_METHOD_IS_ONLY_FOR_INNER_OR_LAZY_PRODUCTS);
176       eigen_assert( (Option==LazyProduct) || (this->rows() == 1 && this->cols() == 1) );
177 
178       return internal::evaluator<Derived>(derived()).coeff(i);
179     }
180 
181 
182 };
183 
184 } // end namespace Eigen
185 
186 #endif // EIGEN_PRODUCT_H
187