1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2009-2010 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_PRODUCTBASE_H
11#define EIGEN_PRODUCTBASE_H
12
13namespace Eigen {
14
15/** \class ProductBase
16  * \ingroup Core_Module
17  *
18  */
19
20namespace internal {
21template<typename Derived, typename _Lhs, typename _Rhs>
22struct traits<ProductBase<Derived,_Lhs,_Rhs> >
23{
24  typedef MatrixXpr XprKind;
25  typedef typename remove_all<_Lhs>::type Lhs;
26  typedef typename remove_all<_Rhs>::type Rhs;
27  typedef typename scalar_product_traits<typename Lhs::Scalar, typename Rhs::Scalar>::ReturnType Scalar;
28  typedef typename promote_storage_type<typename traits<Lhs>::StorageKind,
29                                           typename traits<Rhs>::StorageKind>::ret StorageKind;
30  typedef typename promote_index_type<typename traits<Lhs>::Index,
31                                         typename traits<Rhs>::Index>::type Index;
32  enum {
33    RowsAtCompileTime = traits<Lhs>::RowsAtCompileTime,
34    ColsAtCompileTime = traits<Rhs>::ColsAtCompileTime,
35    MaxRowsAtCompileTime = traits<Lhs>::MaxRowsAtCompileTime,
36    MaxColsAtCompileTime = traits<Rhs>::MaxColsAtCompileTime,
37    Flags = (MaxRowsAtCompileTime==1 ? RowMajorBit : 0)
38          | EvalBeforeNestingBit | EvalBeforeAssigningBit | NestByRefBit,
39                  // Note that EvalBeforeNestingBit and NestByRefBit
40                  // are not used in practice because nested is overloaded for products
41    CoeffReadCost = 0 // FIXME why is it needed ?
42  };
43};
44}
45
46#define EIGEN_PRODUCT_PUBLIC_INTERFACE(Derived) \
47  typedef ProductBase<Derived, Lhs, Rhs > Base; \
48  EIGEN_DENSE_PUBLIC_INTERFACE(Derived) \
49  typedef typename Base::LhsNested LhsNested; \
50  typedef typename Base::_LhsNested _LhsNested; \
51  typedef typename Base::LhsBlasTraits LhsBlasTraits; \
52  typedef typename Base::ActualLhsType ActualLhsType; \
53  typedef typename Base::_ActualLhsType _ActualLhsType; \
54  typedef typename Base::RhsNested RhsNested; \
55  typedef typename Base::_RhsNested _RhsNested; \
56  typedef typename Base::RhsBlasTraits RhsBlasTraits; \
57  typedef typename Base::ActualRhsType ActualRhsType; \
58  typedef typename Base::_ActualRhsType _ActualRhsType; \
59  using Base::m_lhs; \
60  using Base::m_rhs;
61
62template<typename Derived, typename Lhs, typename Rhs>
63class ProductBase : public MatrixBase<Derived>
64{
65  public:
66    typedef MatrixBase<Derived> Base;
67    EIGEN_DENSE_PUBLIC_INTERFACE(ProductBase)
68
69    typedef typename Lhs::Nested LhsNested;
70    typedef typename internal::remove_all<LhsNested>::type _LhsNested;
71    typedef internal::blas_traits<_LhsNested> LhsBlasTraits;
72    typedef typename LhsBlasTraits::DirectLinearAccessType ActualLhsType;
73    typedef typename internal::remove_all<ActualLhsType>::type _ActualLhsType;
74    typedef typename internal::traits<Lhs>::Scalar LhsScalar;
75
76    typedef typename Rhs::Nested RhsNested;
77    typedef typename internal::remove_all<RhsNested>::type _RhsNested;
78    typedef internal::blas_traits<_RhsNested> RhsBlasTraits;
79    typedef typename RhsBlasTraits::DirectLinearAccessType ActualRhsType;
80    typedef typename internal::remove_all<ActualRhsType>::type _ActualRhsType;
81    typedef typename internal::traits<Rhs>::Scalar RhsScalar;
82
83    // Diagonal of a product: no need to evaluate the arguments because they are going to be evaluated only once
84    typedef CoeffBasedProduct<LhsNested, RhsNested, 0> FullyLazyCoeffBaseProductType;
85
86  public:
87
88    typedef typename Base::PlainObject PlainObject;
89
90    ProductBase(const Lhs& a_lhs, const Rhs& a_rhs)
91      : m_lhs(a_lhs), m_rhs(a_rhs)
92    {
93      eigen_assert(a_lhs.cols() == a_rhs.rows()
94        && "invalid matrix product"
95        && "if you wanted a coeff-wise or a dot product use the respective explicit functions");
96    }
97
98    inline Index rows() const { return m_lhs.rows(); }
99    inline Index cols() const { return m_rhs.cols(); }
100
101    template<typename Dest>
102    inline void evalTo(Dest& dst) const { dst.setZero(); scaleAndAddTo(dst,Scalar(1)); }
103
104    template<typename Dest>
105    inline void addTo(Dest& dst) const { scaleAndAddTo(dst,Scalar(1)); }
106
107    template<typename Dest>
108    inline void subTo(Dest& dst) const { scaleAndAddTo(dst,Scalar(-1)); }
109
110    template<typename Dest>
111    inline void scaleAndAddTo(Dest& dst, const Scalar& alpha) const { derived().scaleAndAddTo(dst,alpha); }
112
113    const _LhsNested& lhs() const { return m_lhs; }
114    const _RhsNested& rhs() const { return m_rhs; }
115
116    // Implicit conversion to the nested type (trigger the evaluation of the product)
117    operator const PlainObject& () const
118    {
119      m_result.resize(m_lhs.rows(), m_rhs.cols());
120      derived().evalTo(m_result);
121      return m_result;
122    }
123
124    const Diagonal<const FullyLazyCoeffBaseProductType,0> diagonal() const
125    { return FullyLazyCoeffBaseProductType(m_lhs, m_rhs); }
126
127    template<int Index>
128    const Diagonal<FullyLazyCoeffBaseProductType,Index> diagonal() const
129    { return FullyLazyCoeffBaseProductType(m_lhs, m_rhs); }
130
131    const Diagonal<FullyLazyCoeffBaseProductType,Dynamic> diagonal(Index index) const
132    { return FullyLazyCoeffBaseProductType(m_lhs, m_rhs).diagonal(index); }
133
134    // restrict coeff accessors to 1x1 expressions. No need to care about mutators here since this isnt a Lvalue expression
135    typename Base::CoeffReturnType coeff(Index row, Index col) const
136    {
137#ifdef EIGEN2_SUPPORT
138      return lhs().row(row).cwiseProduct(rhs().col(col).transpose()).sum();
139#else
140      EIGEN_STATIC_ASSERT_SIZE_1x1(Derived)
141      eigen_assert(this->rows() == 1 && this->cols() == 1);
142      Matrix<Scalar,1,1> result = *this;
143      return result.coeff(row,col);
144#endif
145    }
146
147    typename Base::CoeffReturnType coeff(Index i) const
148    {
149      EIGEN_STATIC_ASSERT_SIZE_1x1(Derived)
150      eigen_assert(this->rows() == 1 && this->cols() == 1);
151      Matrix<Scalar,1,1> result = *this;
152      return result.coeff(i);
153    }
154
155    const Scalar& coeffRef(Index row, Index col) const
156    {
157      EIGEN_STATIC_ASSERT_SIZE_1x1(Derived)
158      eigen_assert(this->rows() == 1 && this->cols() == 1);
159      return derived().coeffRef(row,col);
160    }
161
162    const Scalar& coeffRef(Index i) const
163    {
164      EIGEN_STATIC_ASSERT_SIZE_1x1(Derived)
165      eigen_assert(this->rows() == 1 && this->cols() == 1);
166      return derived().coeffRef(i);
167    }
168
169  protected:
170
171    LhsNested m_lhs;
172    RhsNested m_rhs;
173
174    mutable PlainObject m_result;
175};
176
177// here we need to overload the nested rule for products
178// such that the nested type is a const reference to a plain matrix
179namespace internal {
180template<typename Lhs, typename Rhs, int Mode, int N, typename PlainObject>
181struct nested<GeneralProduct<Lhs,Rhs,Mode>, N, PlainObject>
182{
183  typedef PlainObject const& type;
184};
185}
186
187template<typename NestedProduct>
188class ScaledProduct;
189
190// Note that these two operator* functions are not defined as member
191// functions of ProductBase, because, otherwise we would have to
192// define all overloads defined in MatrixBase. Furthermore, Using
193// "using Base::operator*" would not work with MSVC.
194//
195// Also note that here we accept any compatible scalar types
196template<typename Derived,typename Lhs,typename Rhs>
197const ScaledProduct<Derived>
198operator*(const ProductBase<Derived,Lhs,Rhs>& prod, const typename Derived::Scalar& x)
199{ return ScaledProduct<Derived>(prod.derived(), x); }
200
201template<typename Derived,typename Lhs,typename Rhs>
202typename internal::enable_if<!internal::is_same<typename Derived::Scalar,typename Derived::RealScalar>::value,
203                      const ScaledProduct<Derived> >::type
204operator*(const ProductBase<Derived,Lhs,Rhs>& prod, const typename Derived::RealScalar& x)
205{ return ScaledProduct<Derived>(prod.derived(), x); }
206
207
208template<typename Derived,typename Lhs,typename Rhs>
209const ScaledProduct<Derived>
210operator*(const typename Derived::Scalar& x,const ProductBase<Derived,Lhs,Rhs>& prod)
211{ return ScaledProduct<Derived>(prod.derived(), x); }
212
213template<typename Derived,typename Lhs,typename Rhs>
214typename internal::enable_if<!internal::is_same<typename Derived::Scalar,typename Derived::RealScalar>::value,
215                      const ScaledProduct<Derived> >::type
216operator*(const typename Derived::RealScalar& x,const ProductBase<Derived,Lhs,Rhs>& prod)
217{ return ScaledProduct<Derived>(prod.derived(), x); }
218
219namespace internal {
220template<typename NestedProduct>
221struct traits<ScaledProduct<NestedProduct> >
222 : traits<ProductBase<ScaledProduct<NestedProduct>,
223                         typename NestedProduct::_LhsNested,
224                         typename NestedProduct::_RhsNested> >
225{
226  typedef typename traits<NestedProduct>::StorageKind StorageKind;
227};
228}
229
230template<typename NestedProduct>
231class ScaledProduct
232  : public ProductBase<ScaledProduct<NestedProduct>,
233                       typename NestedProduct::_LhsNested,
234                       typename NestedProduct::_RhsNested>
235{
236  public:
237    typedef ProductBase<ScaledProduct<NestedProduct>,
238                       typename NestedProduct::_LhsNested,
239                       typename NestedProduct::_RhsNested> Base;
240    typedef typename Base::Scalar Scalar;
241    typedef typename Base::PlainObject PlainObject;
242//     EIGEN_PRODUCT_PUBLIC_INTERFACE(ScaledProduct)
243
244    ScaledProduct(const NestedProduct& prod, const Scalar& x)
245    : Base(prod.lhs(),prod.rhs()), m_prod(prod), m_alpha(x) {}
246
247    template<typename Dest>
248    inline void evalTo(Dest& dst) const { dst.setZero(); scaleAndAddTo(dst, Scalar(1)); }
249
250    template<typename Dest>
251    inline void addTo(Dest& dst) const { scaleAndAddTo(dst, Scalar(1)); }
252
253    template<typename Dest>
254    inline void subTo(Dest& dst) const { scaleAndAddTo(dst, Scalar(-1)); }
255
256    template<typename Dest>
257    inline void scaleAndAddTo(Dest& dst, const Scalar& a_alpha) const { m_prod.derived().scaleAndAddTo(dst,a_alpha * m_alpha); }
258
259    const Scalar& alpha() const { return m_alpha; }
260
261  protected:
262    const NestedProduct& m_prod;
263    Scalar m_alpha;
264};
265
266/** \internal
267  * Overloaded to perform an efficient C = (A*B).lazy() */
268template<typename Derived>
269template<typename ProductDerived, typename Lhs, typename Rhs>
270Derived& MatrixBase<Derived>::lazyAssign(const ProductBase<ProductDerived, Lhs,Rhs>& other)
271{
272  other.derived().evalTo(derived());
273  return derived();
274}
275
276} // end namespace Eigen
277
278#endif // EIGEN_PRODUCTBASE_H
279