1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2007-2009 Benoit Jacob <jacob.benoit.1@gmail.com> 5 // Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr> 6 // 7 // This Source Code Form is subject to the terms of the Mozilla 8 // Public License v. 2.0. If a copy of the MPL was not distributed 9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 10 11 #ifndef EIGEN_DIAGONAL_H 12 #define EIGEN_DIAGONAL_H 13 14 namespace Eigen { 15 16 /** \class Diagonal 17 * \ingroup Core_Module 18 * 19 * \brief Expression of a diagonal/subdiagonal/superdiagonal in a matrix 20 * 21 * \param MatrixType the type of the object in which we are taking a sub/main/super diagonal 22 * \param DiagIndex the index of the sub/super diagonal. The default is 0 and it means the main diagonal. 23 * A positive value means a superdiagonal, a negative value means a subdiagonal. 24 * You can also use Dynamic so the index can be set at runtime. 25 * 26 * The matrix is not required to be square. 27 * 28 * This class represents an expression of the main diagonal, or any sub/super diagonal 29 * of a square matrix. It is the return type of MatrixBase::diagonal() and MatrixBase::diagonal(Index) and most of the 30 * time this is the only way it is used. 31 * 32 * \sa MatrixBase::diagonal(), MatrixBase::diagonal(Index) 33 */ 34 35 namespace internal { 36 template<typename MatrixType, int DiagIndex> 37 struct traits<Diagonal<MatrixType,DiagIndex> > 38 : traits<MatrixType> 39 { 40 typedef typename nested<MatrixType>::type MatrixTypeNested; 41 typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested; 42 typedef typename MatrixType::StorageKind StorageKind; 43 enum { 44 RowsAtCompileTime = (int(DiagIndex) == Dynamic || int(MatrixType::SizeAtCompileTime) == Dynamic) ? Dynamic 45 : (EIGEN_PLAIN_ENUM_MIN(MatrixType::RowsAtCompileTime - EIGEN_PLAIN_ENUM_MAX(-DiagIndex, 0), 46 MatrixType::ColsAtCompileTime - EIGEN_PLAIN_ENUM_MAX( DiagIndex, 0))), 47 ColsAtCompileTime = 1, 48 MaxRowsAtCompileTime = int(MatrixType::MaxSizeAtCompileTime) == Dynamic ? Dynamic 49 : DiagIndex == Dynamic ? EIGEN_SIZE_MIN_PREFER_FIXED(MatrixType::MaxRowsAtCompileTime, 50 MatrixType::MaxColsAtCompileTime) 51 : (EIGEN_PLAIN_ENUM_MIN(MatrixType::MaxRowsAtCompileTime - EIGEN_PLAIN_ENUM_MAX(-DiagIndex, 0), 52 MatrixType::MaxColsAtCompileTime - EIGEN_PLAIN_ENUM_MAX( DiagIndex, 0))), 53 MaxColsAtCompileTime = 1, 54 MaskLvalueBit = is_lvalue<MatrixType>::value ? LvalueBit : 0, 55 Flags = (unsigned int)_MatrixTypeNested::Flags & (HereditaryBits | LinearAccessBit | MaskLvalueBit | DirectAccessBit) & ~RowMajorBit, 56 CoeffReadCost = _MatrixTypeNested::CoeffReadCost, 57 MatrixTypeOuterStride = outer_stride_at_compile_time<MatrixType>::ret, 58 InnerStrideAtCompileTime = MatrixTypeOuterStride == Dynamic ? Dynamic : MatrixTypeOuterStride+1, 59 OuterStrideAtCompileTime = 0 60 }; 61 }; 62 } 63 64 template<typename MatrixType, int DiagIndex> class Diagonal 65 : public internal::dense_xpr_base< Diagonal<MatrixType,DiagIndex> >::type 66 { 67 public: 68 69 typedef typename internal::dense_xpr_base<Diagonal>::type Base; 70 EIGEN_DENSE_PUBLIC_INTERFACE(Diagonal) 71 72 inline Diagonal(MatrixType& matrix, Index index = DiagIndex) : m_matrix(matrix), m_index(index) {} 73 74 EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Diagonal) 75 76 inline Index rows() const 77 { return m_index.value()<0 ? (std::min)(m_matrix.cols(),m_matrix.rows()+m_index.value()) : (std::min)(m_matrix.rows(),m_matrix.cols()-m_index.value()); } 78 79 inline Index cols() const { return 1; } 80 81 inline Index innerStride() const 82 { 83 return m_matrix.outerStride() + 1; 84 } 85 86 inline Index outerStride() const 87 { 88 return 0; 89 } 90 91 typedef typename internal::conditional< 92 internal::is_lvalue<MatrixType>::value, 93 Scalar, 94 const Scalar 95 >::type ScalarWithConstIfNotLvalue; 96 97 inline ScalarWithConstIfNotLvalue* data() { return &(m_matrix.const_cast_derived().coeffRef(rowOffset(), colOffset())); } 98 inline const Scalar* data() const { return &(m_matrix.const_cast_derived().coeffRef(rowOffset(), colOffset())); } 99 100 inline Scalar& coeffRef(Index row, Index) 101 { 102 EIGEN_STATIC_ASSERT_LVALUE(MatrixType) 103 return m_matrix.const_cast_derived().coeffRef(row+rowOffset(), row+colOffset()); 104 } 105 106 inline const Scalar& coeffRef(Index row, Index) const 107 { 108 return m_matrix.const_cast_derived().coeffRef(row+rowOffset(), row+colOffset()); 109 } 110 111 inline CoeffReturnType coeff(Index row, Index) const 112 { 113 return m_matrix.coeff(row+rowOffset(), row+colOffset()); 114 } 115 116 inline Scalar& coeffRef(Index index) 117 { 118 EIGEN_STATIC_ASSERT_LVALUE(MatrixType) 119 return m_matrix.const_cast_derived().coeffRef(index+rowOffset(), index+colOffset()); 120 } 121 122 inline const Scalar& coeffRef(Index index) const 123 { 124 return m_matrix.const_cast_derived().coeffRef(index+rowOffset(), index+colOffset()); 125 } 126 127 inline CoeffReturnType coeff(Index index) const 128 { 129 return m_matrix.coeff(index+rowOffset(), index+colOffset()); 130 } 131 132 const typename internal::remove_all<typename MatrixType::Nested>::type& 133 nestedExpression() const 134 { 135 return m_matrix; 136 } 137 138 int index() const 139 { 140 return m_index.value(); 141 } 142 143 protected: 144 typename MatrixType::Nested m_matrix; 145 const internal::variable_if_dynamic<Index, DiagIndex> m_index; 146 147 private: 148 // some compilers may fail to optimize std::max etc in case of compile-time constants... 149 EIGEN_STRONG_INLINE Index absDiagIndex() const { return m_index.value()>0 ? m_index.value() : -m_index.value(); } 150 EIGEN_STRONG_INLINE Index rowOffset() const { return m_index.value()>0 ? 0 : -m_index.value(); } 151 EIGEN_STRONG_INLINE Index colOffset() const { return m_index.value()>0 ? m_index.value() : 0; } 152 // triger a compile time error is someone try to call packet 153 template<int LoadMode> typename MatrixType::PacketReturnType packet(Index) const; 154 template<int LoadMode> typename MatrixType::PacketReturnType packet(Index,Index) const; 155 }; 156 157 /** \returns an expression of the main diagonal of the matrix \c *this 158 * 159 * \c *this is not required to be square. 160 * 161 * Example: \include MatrixBase_diagonal.cpp 162 * Output: \verbinclude MatrixBase_diagonal.out 163 * 164 * \sa class Diagonal */ 165 template<typename Derived> 166 inline typename MatrixBase<Derived>::DiagonalReturnType 167 MatrixBase<Derived>::diagonal() 168 { 169 return derived(); 170 } 171 172 /** This is the const version of diagonal(). */ 173 template<typename Derived> 174 inline const typename MatrixBase<Derived>::ConstDiagonalReturnType 175 MatrixBase<Derived>::diagonal() const 176 { 177 return ConstDiagonalReturnType(derived()); 178 } 179 180 /** \returns an expression of the \a DiagIndex-th sub or super diagonal of the matrix \c *this 181 * 182 * \c *this is not required to be square. 183 * 184 * The template parameter \a DiagIndex represent a super diagonal if \a DiagIndex > 0 185 * and a sub diagonal otherwise. \a DiagIndex == 0 is equivalent to the main diagonal. 186 * 187 * Example: \include MatrixBase_diagonal_int.cpp 188 * Output: \verbinclude MatrixBase_diagonal_int.out 189 * 190 * \sa MatrixBase::diagonal(), class Diagonal */ 191 template<typename Derived> 192 inline typename MatrixBase<Derived>::template DiagonalIndexReturnType<Dynamic>::Type 193 MatrixBase<Derived>::diagonal(Index index) 194 { 195 return typename DiagonalIndexReturnType<Dynamic>::Type(derived(), index); 196 } 197 198 /** This is the const version of diagonal(Index). */ 199 template<typename Derived> 200 inline typename MatrixBase<Derived>::template ConstDiagonalIndexReturnType<Dynamic>::Type 201 MatrixBase<Derived>::diagonal(Index index) const 202 { 203 return typename ConstDiagonalIndexReturnType<Dynamic>::Type(derived(), index); 204 } 205 206 /** \returns an expression of the \a DiagIndex-th sub or super diagonal of the matrix \c *this 207 * 208 * \c *this is not required to be square. 209 * 210 * The template parameter \a DiagIndex represent a super diagonal if \a DiagIndex > 0 211 * and a sub diagonal otherwise. \a DiagIndex == 0 is equivalent to the main diagonal. 212 * 213 * Example: \include MatrixBase_diagonal_template_int.cpp 214 * Output: \verbinclude MatrixBase_diagonal_template_int.out 215 * 216 * \sa MatrixBase::diagonal(), class Diagonal */ 217 template<typename Derived> 218 template<int Index> 219 inline typename MatrixBase<Derived>::template DiagonalIndexReturnType<Index>::Type 220 MatrixBase<Derived>::diagonal() 221 { 222 return derived(); 223 } 224 225 /** This is the const version of diagonal<int>(). */ 226 template<typename Derived> 227 template<int Index> 228 inline typename MatrixBase<Derived>::template ConstDiagonalIndexReturnType<Index>::Type 229 MatrixBase<Derived>::diagonal() const 230 { 231 return derived(); 232 } 233 234 } // end namespace Eigen 235 236 #endif // EIGEN_DIAGONAL_H 237