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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>
5 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
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_CWISE_BINARY_OP_H
12 #define EIGEN_CWISE_BINARY_OP_H
13 
14 namespace Eigen {
15 
16 /** \class CwiseBinaryOp
17   * \ingroup Core_Module
18   *
19   * \brief Generic expression where a coefficient-wise binary operator is applied to two expressions
20   *
21   * \param BinaryOp template functor implementing the operator
22   * \param Lhs the type of the left-hand side
23   * \param Rhs the type of the right-hand side
24   *
25   * This class represents an expression  where a coefficient-wise binary operator is applied to two expressions.
26   * It is the return type of binary operators, by which we mean only those binary operators where
27   * both the left-hand side and the right-hand side are Eigen expressions.
28   * For example, the return type of matrix1+matrix2 is a CwiseBinaryOp.
29   *
30   * Most of the time, this is the only way that it is used, so you typically don't have to name
31   * CwiseBinaryOp types explicitly.
32   *
33   * \sa MatrixBase::binaryExpr(const MatrixBase<OtherDerived> &,const CustomBinaryOp &) const, class CwiseUnaryOp, class CwiseNullaryOp
34   */
35 
36 namespace internal {
37 template<typename BinaryOp, typename Lhs, typename Rhs>
38 struct traits<CwiseBinaryOp<BinaryOp, Lhs, Rhs> >
39 {
40   // we must not inherit from traits<Lhs> since it has
41   // the potential to cause problems with MSVC
42   typedef typename remove_all<Lhs>::type Ancestor;
43   typedef typename traits<Ancestor>::XprKind XprKind;
44   enum {
45     RowsAtCompileTime = traits<Ancestor>::RowsAtCompileTime,
46     ColsAtCompileTime = traits<Ancestor>::ColsAtCompileTime,
47     MaxRowsAtCompileTime = traits<Ancestor>::MaxRowsAtCompileTime,
48     MaxColsAtCompileTime = traits<Ancestor>::MaxColsAtCompileTime
49   };
50 
51   // even though we require Lhs and Rhs to have the same scalar type (see CwiseBinaryOp constructor),
52   // we still want to handle the case when the result type is different.
53   typedef typename result_of<
54                      BinaryOp(
55                        typename Lhs::Scalar,
56                        typename Rhs::Scalar
57                      )
58                    >::type Scalar;
59   typedef typename promote_storage_type<typename traits<Lhs>::StorageKind,
60                                            typename traits<Rhs>::StorageKind>::ret StorageKind;
61   typedef typename promote_index_type<typename traits<Lhs>::Index,
62                                          typename traits<Rhs>::Index>::type Index;
63   typedef typename Lhs::Nested LhsNested;
64   typedef typename Rhs::Nested RhsNested;
65   typedef typename remove_reference<LhsNested>::type _LhsNested;
66   typedef typename remove_reference<RhsNested>::type _RhsNested;
67   enum {
68     LhsCoeffReadCost = _LhsNested::CoeffReadCost,
69     RhsCoeffReadCost = _RhsNested::CoeffReadCost,
70     LhsFlags = _LhsNested::Flags,
71     RhsFlags = _RhsNested::Flags,
72     SameType = is_same<typename _LhsNested::Scalar,typename _RhsNested::Scalar>::value,
73     StorageOrdersAgree = (int(Lhs::Flags)&RowMajorBit)==(int(Rhs::Flags)&RowMajorBit),
74     Flags0 = (int(LhsFlags) | int(RhsFlags)) & (
75         HereditaryBits
76       | (int(LhsFlags) & int(RhsFlags) &
77            ( AlignedBit
78            | (StorageOrdersAgree ? LinearAccessBit : 0)
79            | (functor_traits<BinaryOp>::PacketAccess && StorageOrdersAgree && SameType ? PacketAccessBit : 0)
80            )
81         )
82      ),
83     Flags = (Flags0 & ~RowMajorBit) | (LhsFlags & RowMajorBit),
84     CoeffReadCost = LhsCoeffReadCost + RhsCoeffReadCost + functor_traits<BinaryOp>::Cost
85   };
86 };
87 } // end namespace internal
88 
89 // we require Lhs and Rhs to have the same scalar type. Currently there is no example of a binary functor
90 // that would take two operands of different types. If there were such an example, then this check should be
91 // moved to the BinaryOp functors, on a per-case basis. This would however require a change in the BinaryOp functors, as
92 // currently they take only one typename Scalar template parameter.
93 // It is tempting to always allow mixing different types but remember that this is often impossible in the vectorized paths.
94 // So allowing mixing different types gives very unexpected errors when enabling vectorization, when the user tries to
95 // add together a float matrix and a double matrix.
96 #define EIGEN_CHECK_BINARY_COMPATIBILIY(BINOP,LHS,RHS) \
97   EIGEN_STATIC_ASSERT((internal::functor_is_product_like<BINOP>::ret \
98                         ? int(internal::scalar_product_traits<LHS, RHS>::Defined) \
99                         : int(internal::is_same<LHS, RHS>::value)), \
100     YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY)
101 
102 template<typename BinaryOp, typename Lhs, typename Rhs, typename StorageKind>
103 class CwiseBinaryOpImpl;
104 
105 template<typename BinaryOp, typename Lhs, typename Rhs>
106 class CwiseBinaryOp : internal::no_assignment_operator,
107   public CwiseBinaryOpImpl<
108           BinaryOp, Lhs, Rhs,
109           typename internal::promote_storage_type<typename internal::traits<Lhs>::StorageKind,
110                                            typename internal::traits<Rhs>::StorageKind>::ret>
111 {
112   public:
113 
114     typedef typename CwiseBinaryOpImpl<
115         BinaryOp, Lhs, Rhs,
116         typename internal::promote_storage_type<typename internal::traits<Lhs>::StorageKind,
117                                          typename internal::traits<Rhs>::StorageKind>::ret>::Base Base;
118     EIGEN_GENERIC_PUBLIC_INTERFACE(CwiseBinaryOp)
119 
120     typedef typename internal::nested<Lhs>::type LhsNested;
121     typedef typename internal::nested<Rhs>::type RhsNested;
122     typedef typename internal::remove_reference<LhsNested>::type _LhsNested;
123     typedef typename internal::remove_reference<RhsNested>::type _RhsNested;
124 
125     EIGEN_STRONG_INLINE CwiseBinaryOp(const Lhs& aLhs, const Rhs& aRhs, const BinaryOp& func = BinaryOp())
126       : m_lhs(aLhs), m_rhs(aRhs), m_functor(func)
127     {
128       EIGEN_CHECK_BINARY_COMPATIBILIY(BinaryOp,typename Lhs::Scalar,typename Rhs::Scalar);
129       // require the sizes to match
130       EIGEN_STATIC_ASSERT_SAME_MATRIX_SIZE(Lhs, Rhs)
131       eigen_assert(aLhs.rows() == aRhs.rows() && aLhs.cols() == aRhs.cols());
132     }
133 
134     EIGEN_STRONG_INLINE Index rows() const {
135       // return the fixed size type if available to enable compile time optimizations
136       if (internal::traits<typename internal::remove_all<LhsNested>::type>::RowsAtCompileTime==Dynamic)
137         return m_rhs.rows();
138       else
139         return m_lhs.rows();
140     }
141     EIGEN_STRONG_INLINE Index cols() const {
142       // return the fixed size type if available to enable compile time optimizations
143       if (internal::traits<typename internal::remove_all<LhsNested>::type>::ColsAtCompileTime==Dynamic)
144         return m_rhs.cols();
145       else
146         return m_lhs.cols();
147     }
148 
149     /** \returns the left hand side nested expression */
150     const _LhsNested& lhs() const { return m_lhs; }
151     /** \returns the right hand side nested expression */
152     const _RhsNested& rhs() const { return m_rhs; }
153     /** \returns the functor representing the binary operation */
154     const BinaryOp& functor() const { return m_functor; }
155 
156   protected:
157     LhsNested m_lhs;
158     RhsNested m_rhs;
159     const BinaryOp m_functor;
160 };
161 
162 template<typename BinaryOp, typename Lhs, typename Rhs>
163 class CwiseBinaryOpImpl<BinaryOp, Lhs, Rhs, Dense>
164   : public internal::dense_xpr_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs> >::type
165 {
166     typedef CwiseBinaryOp<BinaryOp, Lhs, Rhs> Derived;
167   public:
168 
169     typedef typename internal::dense_xpr_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs> >::type Base;
170     EIGEN_DENSE_PUBLIC_INTERFACE( Derived )
171 
172     EIGEN_STRONG_INLINE const Scalar coeff(Index rowId, Index colId) const
173     {
174       return derived().functor()(derived().lhs().coeff(rowId, colId),
175                                  derived().rhs().coeff(rowId, colId));
176     }
177 
178     template<int LoadMode>
179     EIGEN_STRONG_INLINE PacketScalar packet(Index rowId, Index colId) const
180     {
181       return derived().functor().packetOp(derived().lhs().template packet<LoadMode>(rowId, colId),
182                                           derived().rhs().template packet<LoadMode>(rowId, colId));
183     }
184 
185     EIGEN_STRONG_INLINE const Scalar coeff(Index index) const
186     {
187       return derived().functor()(derived().lhs().coeff(index),
188                                  derived().rhs().coeff(index));
189     }
190 
191     template<int LoadMode>
192     EIGEN_STRONG_INLINE PacketScalar packet(Index index) const
193     {
194       return derived().functor().packetOp(derived().lhs().template packet<LoadMode>(index),
195                                           derived().rhs().template packet<LoadMode>(index));
196     }
197 };
198 
199 /** replaces \c *this by \c *this - \a other.
200   *
201   * \returns a reference to \c *this
202   */
203 template<typename Derived>
204 template<typename OtherDerived>
205 EIGEN_STRONG_INLINE Derived &
206 MatrixBase<Derived>::operator-=(const MatrixBase<OtherDerived> &other)
207 {
208   SelfCwiseBinaryOp<internal::scalar_difference_op<Scalar>, Derived, OtherDerived> tmp(derived());
209   tmp = other.derived();
210   return derived();
211 }
212 
213 /** replaces \c *this by \c *this + \a other.
214   *
215   * \returns a reference to \c *this
216   */
217 template<typename Derived>
218 template<typename OtherDerived>
219 EIGEN_STRONG_INLINE Derived &
220 MatrixBase<Derived>::operator+=(const MatrixBase<OtherDerived>& other)
221 {
222   SelfCwiseBinaryOp<internal::scalar_sum_op<Scalar>, Derived, OtherDerived> tmp(derived());
223   tmp = other.derived();
224   return derived();
225 }
226 
227 } // end namespace Eigen
228 
229 #endif // EIGEN_CWISE_BINARY_OP_H
230