Michael Ernst Peter / Eigen

src/Core/DiagonalMatrix.h@1:3b8049da21b8, 2019-09-24 (annotated)

Committer:
jsoh91
Date:
Tue Sep 24 00:18:23 2019 +0000
Revision:
1:3b8049da21b8
Parent:
0:13a5d365ba16 
ignore and revise some of error parts

Who changed what in which revision?

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ykuroda 0:13a5d365ba16 1 // This file is part of Eigen, a lightweight C++ template library
ykuroda 0:13a5d365ba16 2 // for linear algebra.
ykuroda 0:13a5d365ba16 3 //
ykuroda 0:13a5d365ba16 4 // Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
ykuroda 0:13a5d365ba16 5 // Copyright (C) 2007-2009 Benoit Jacob <jacob.benoit.1@gmail.com>
ykuroda 0:13a5d365ba16 6 //
ykuroda 0:13a5d365ba16 7 // This Source Code Form is subject to the terms of the Mozilla
ykuroda 0:13a5d365ba16 8 // Public License v. 2.0. If a copy of the MPL was not distributed
ykuroda 0:13a5d365ba16 9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
ykuroda 0:13a5d365ba16 10
ykuroda 0:13a5d365ba16 11 #ifndef EIGEN_DIAGONALMATRIX_H
ykuroda 0:13a5d365ba16 12 #define EIGEN_DIAGONALMATRIX_H
ykuroda 0:13a5d365ba16 13
ykuroda 0:13a5d365ba16 14 namespace Eigen {
ykuroda 0:13a5d365ba16 15
ykuroda 0:13a5d365ba16 16 #ifndef EIGEN_PARSED_BY_DOXYGEN
ykuroda 0:13a5d365ba16 17 template<typename Derived>
ykuroda 0:13a5d365ba16 18 class DiagonalBase : public EigenBase<Derived>
ykuroda 0:13a5d365ba16 19 {
ykuroda 0:13a5d365ba16 20 public:
ykuroda 0:13a5d365ba16 21 typedef typename internal::traits<Derived>::DiagonalVectorType DiagonalVectorType;
ykuroda 0:13a5d365ba16 22 typedef typename DiagonalVectorType::Scalar Scalar;
ykuroda 0:13a5d365ba16 23 typedef typename DiagonalVectorType::RealScalar RealScalar;
ykuroda 0:13a5d365ba16 24 typedef typename internal::traits<Derived>::StorageKind StorageKind;
ykuroda 0:13a5d365ba16 25 typedef typename internal::traits<Derived>::Index Index;
ykuroda 0:13a5d365ba16 26
ykuroda 0:13a5d365ba16 27 enum {
ykuroda 0:13a5d365ba16 28 RowsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 29 ColsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 30 MaxRowsAtCompileTime = DiagonalVectorType::MaxSizeAtCompileTime,
ykuroda 0:13a5d365ba16 31 MaxColsAtCompileTime = DiagonalVectorType::MaxSizeAtCompileTime,
ykuroda 0:13a5d365ba16 32 IsVectorAtCompileTime = 0,
ykuroda 0:13a5d365ba16 33 Flags = 0
ykuroda 0:13a5d365ba16 34 };
ykuroda 0:13a5d365ba16 35
ykuroda 0:13a5d365ba16 36 typedef Matrix<Scalar, RowsAtCompileTime, ColsAtCompileTime, 0, MaxRowsAtCompileTime, MaxColsAtCompileTime> DenseMatrixType;
ykuroda 0:13a5d365ba16 37 typedef DenseMatrixType DenseType;
ykuroda 0:13a5d365ba16 38 typedef DiagonalMatrix<Scalar,DiagonalVectorType::SizeAtCompileTime,DiagonalVectorType::MaxSizeAtCompileTime> PlainObject;
ykuroda 0:13a5d365ba16 39
ykuroda 0:13a5d365ba16 40 inline const Derived& derived() const { return *static_cast<const Derived*>(this); }
ykuroda 0:13a5d365ba16 41 inline Derived& derived() { return *static_cast<Derived*>(this); }
ykuroda 0:13a5d365ba16 42
ykuroda 0:13a5d365ba16 43 DenseMatrixType toDenseMatrix() const { return derived(); }
ykuroda 0:13a5d365ba16 44 template<typename DenseDerived>
ykuroda 0:13a5d365ba16 45 void evalTo(MatrixBase<DenseDerived> &other) const;
ykuroda 0:13a5d365ba16 46 template<typename DenseDerived>
ykuroda 0:13a5d365ba16 47 void addTo(MatrixBase<DenseDerived> &other) const
ykuroda 0:13a5d365ba16 48 { other.diagonal() += diagonal(); }
ykuroda 0:13a5d365ba16 49 template<typename DenseDerived>
ykuroda 0:13a5d365ba16 50 void subTo(MatrixBase<DenseDerived> &other) const
ykuroda 0:13a5d365ba16 51 { other.diagonal() -= diagonal(); }
ykuroda 0:13a5d365ba16 52
ykuroda 0:13a5d365ba16 53 inline const DiagonalVectorType& diagonal() const { return derived().diagonal(); }
ykuroda 0:13a5d365ba16 54 inline DiagonalVectorType& diagonal() { return derived().diagonal(); }
ykuroda 0:13a5d365ba16 55
ykuroda 0:13a5d365ba16 56 inline Index rows() const { return diagonal().size(); }
ykuroda 0:13a5d365ba16 57 inline Index cols() const { return diagonal().size(); }
ykuroda 0:13a5d365ba16 58
ykuroda 0:13a5d365ba16 59 /** \returns the diagonal matrix product of \c *this by the matrix \a matrix.
ykuroda 0:13a5d365ba16 60 */
ykuroda 0:13a5d365ba16 61 template<typename MatrixDerived>
ykuroda 0:13a5d365ba16 62 const DiagonalProduct<MatrixDerived, Derived, OnTheLeft>
ykuroda 0:13a5d365ba16 63 operator*(const MatrixBase<MatrixDerived> &matrix) const
ykuroda 0:13a5d365ba16 64 {
ykuroda 0:13a5d365ba16 65 return DiagonalProduct<MatrixDerived, Derived, OnTheLeft>(matrix.derived(), derived());
ykuroda 0:13a5d365ba16 66 }
ykuroda 0:13a5d365ba16 67
ykuroda 0:13a5d365ba16 68 inline const DiagonalWrapper<const CwiseUnaryOp<internal::scalar_inverse_op<Scalar>, const DiagonalVectorType> >
ykuroda 0:13a5d365ba16 69 inverse() const
ykuroda 0:13a5d365ba16 70 {
ykuroda 0:13a5d365ba16 71 return diagonal().cwiseInverse();
ykuroda 0:13a5d365ba16 72 }
ykuroda 0:13a5d365ba16 73
ykuroda 0:13a5d365ba16 74 inline const DiagonalWrapper<const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DiagonalVectorType> >
ykuroda 0:13a5d365ba16 75 operator*(const Scalar& scalar) const
ykuroda 0:13a5d365ba16 76 {
ykuroda 0:13a5d365ba16 77 return diagonal() * scalar;
ykuroda 0:13a5d365ba16 78 }
ykuroda 0:13a5d365ba16 79 friend inline const DiagonalWrapper<const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DiagonalVectorType> >
ykuroda 0:13a5d365ba16 80 operator*(const Scalar& scalar, const DiagonalBase& other)
ykuroda 0:13a5d365ba16 81 {
ykuroda 0:13a5d365ba16 82 return other.diagonal() * scalar;
ykuroda 0:13a5d365ba16 83 }
ykuroda 0:13a5d365ba16 84
ykuroda 0:13a5d365ba16 85 #ifdef EIGEN2_SUPPORT
ykuroda 0:13a5d365ba16 86 template<typename OtherDerived>
ykuroda 0:13a5d365ba16 87 bool isApprox(const DiagonalBase<OtherDerived>& other, typename NumTraits<Scalar>::Real precision = NumTraits<Scalar>::dummy_precision()) const
ykuroda 0:13a5d365ba16 88 {
ykuroda 0:13a5d365ba16 89 return diagonal().isApprox(other.diagonal(), precision);
ykuroda 0:13a5d365ba16 90 }
ykuroda 0:13a5d365ba16 91 template<typename OtherDerived>
ykuroda 0:13a5d365ba16 92 bool isApprox(const MatrixBase<OtherDerived>& other, typename NumTraits<Scalar>::Real precision = NumTraits<Scalar>::dummy_precision()) const
ykuroda 0:13a5d365ba16 93 {
ykuroda 0:13a5d365ba16 94 return toDenseMatrix().isApprox(other, precision);
ykuroda 0:13a5d365ba16 95 }
ykuroda 0:13a5d365ba16 96 #endif
ykuroda 0:13a5d365ba16 97 };
ykuroda 0:13a5d365ba16 98
ykuroda 0:13a5d365ba16 99 template<typename Derived>
ykuroda 0:13a5d365ba16 100 template<typename DenseDerived>
ykuroda 0:13a5d365ba16 101 void DiagonalBase<Derived>::evalTo(MatrixBase<DenseDerived> &other) const
ykuroda 0:13a5d365ba16 102 {
ykuroda 0:13a5d365ba16 103 other.setZero();
ykuroda 0:13a5d365ba16 104 other.diagonal() = diagonal();
ykuroda 0:13a5d365ba16 105 }
ykuroda 0:13a5d365ba16 106 #endif
ykuroda 0:13a5d365ba16 107
ykuroda 0:13a5d365ba16 108 /** \class DiagonalMatrix
ykuroda 0:13a5d365ba16 109 * \ingroup Core_Module
ykuroda 0:13a5d365ba16 110 *
ykuroda 0:13a5d365ba16 111 * \brief Represents a diagonal matrix with its storage
ykuroda 0:13a5d365ba16 112 *
ykuroda 0:13a5d365ba16 113 * \param _Scalar the type of coefficients
ykuroda 0:13a5d365ba16 114 * \param SizeAtCompileTime the dimension of the matrix, or Dynamic
ykuroda 0:13a5d365ba16 115 * \param MaxSizeAtCompileTime the dimension of the matrix, or Dynamic. This parameter is optional and defaults
ykuroda 0:13a5d365ba16 116 * to SizeAtCompileTime. Most of the time, you do not need to specify it.
ykuroda 0:13a5d365ba16 117 *
ykuroda 0:13a5d365ba16 118 * \sa class DiagonalWrapper
ykuroda 0:13a5d365ba16 119 */
ykuroda 0:13a5d365ba16 120
ykuroda 0:13a5d365ba16 121 namespace internal {
ykuroda 0:13a5d365ba16 122 template<typename _Scalar, int SizeAtCompileTime, int MaxSizeAtCompileTime>
ykuroda 0:13a5d365ba16 123 struct traits<DiagonalMatrix<_Scalar,SizeAtCompileTime,MaxSizeAtCompileTime> >
ykuroda 0:13a5d365ba16 124 : traits<Matrix<_Scalar,SizeAtCompileTime,SizeAtCompileTime,0,MaxSizeAtCompileTime,MaxSizeAtCompileTime> >
ykuroda 0:13a5d365ba16 125 {
ykuroda 0:13a5d365ba16 126 typedef Matrix<_Scalar,SizeAtCompileTime,1,0,MaxSizeAtCompileTime,1> DiagonalVectorType;
ykuroda 0:13a5d365ba16 127 typedef Dense StorageKind;
ykuroda 0:13a5d365ba16 128 typedef DenseIndex Index;
ykuroda 0:13a5d365ba16 129 enum {
ykuroda 0:13a5d365ba16 130 Flags = LvalueBit
ykuroda 0:13a5d365ba16 131 };
ykuroda 0:13a5d365ba16 132 };
ykuroda 0:13a5d365ba16 133 }
ykuroda 0:13a5d365ba16 134 template<typename _Scalar, int SizeAtCompileTime, int MaxSizeAtCompileTime>
ykuroda 0:13a5d365ba16 135 class DiagonalMatrix
ykuroda 0:13a5d365ba16 136 : public DiagonalBase<DiagonalMatrix<_Scalar,SizeAtCompileTime,MaxSizeAtCompileTime> >
ykuroda 0:13a5d365ba16 137 {
ykuroda 0:13a5d365ba16 138 public:
ykuroda 0:13a5d365ba16 139 #ifndef EIGEN_PARSED_BY_DOXYGEN
ykuroda 0:13a5d365ba16 140 typedef typename internal::traits<DiagonalMatrix>::DiagonalVectorType DiagonalVectorType;
ykuroda 0:13a5d365ba16 141 typedef const DiagonalMatrix& Nested;
ykuroda 0:13a5d365ba16 142 typedef _Scalar Scalar;
ykuroda 0:13a5d365ba16 143 typedef typename internal::traits<DiagonalMatrix>::StorageKind StorageKind;
ykuroda 0:13a5d365ba16 144 typedef typename internal::traits<DiagonalMatrix>::Index Index;
ykuroda 0:13a5d365ba16 145 #endif
ykuroda 0:13a5d365ba16 146
ykuroda 0:13a5d365ba16 147 protected:
ykuroda 0:13a5d365ba16 148
ykuroda 0:13a5d365ba16 149 DiagonalVectorType m_diagonal;
ykuroda 0:13a5d365ba16 150
ykuroda 0:13a5d365ba16 151 public:
ykuroda 0:13a5d365ba16 152
ykuroda 0:13a5d365ba16 153 /** const version of diagonal(). */
ykuroda 0:13a5d365ba16 154 inline const DiagonalVectorType& diagonal() const { return m_diagonal; }
ykuroda 0:13a5d365ba16 155 /** \returns a reference to the stored vector of diagonal coefficients. */
ykuroda 0:13a5d365ba16 156 inline DiagonalVectorType& diagonal() { return m_diagonal; }
ykuroda 0:13a5d365ba16 157
ykuroda 0:13a5d365ba16 158 /** Default constructor without initialization */
ykuroda 0:13a5d365ba16 159 inline DiagonalMatrix() {}
ykuroda 0:13a5d365ba16 160
ykuroda 0:13a5d365ba16 161 /** Constructs a diagonal matrix with given dimension */
ykuroda 0:13a5d365ba16 162 inline DiagonalMatrix(Index dim) : m_diagonal(dim) {}
ykuroda 0:13a5d365ba16 163
ykuroda 0:13a5d365ba16 164 /** 2D constructor. */
ykuroda 0:13a5d365ba16 165 inline DiagonalMatrix(const Scalar& x, const Scalar& y) : m_diagonal(x,y) {}
ykuroda 0:13a5d365ba16 166
ykuroda 0:13a5d365ba16 167 /** 3D constructor. */
ykuroda 0:13a5d365ba16 168 inline DiagonalMatrix(const Scalar& x, const Scalar& y, const Scalar& z) : m_diagonal(x,y,z) {}
ykuroda 0:13a5d365ba16 169
ykuroda 0:13a5d365ba16 170 /** Copy constructor. */
ykuroda 0:13a5d365ba16 171 template<typename OtherDerived>
ykuroda 0:13a5d365ba16 172 inline DiagonalMatrix(const DiagonalBase<OtherDerived>& other) : m_diagonal(other.diagonal()) {}
ykuroda 0:13a5d365ba16 173
ykuroda 0:13a5d365ba16 174 #ifndef EIGEN_PARSED_BY_DOXYGEN
ykuroda 0:13a5d365ba16 175 /** copy constructor. prevent a default copy constructor from hiding the other templated constructor */
ykuroda 0:13a5d365ba16 176 inline DiagonalMatrix(const DiagonalMatrix& other) : m_diagonal(other.diagonal()) {}
ykuroda 0:13a5d365ba16 177 #endif
ykuroda 0:13a5d365ba16 178
ykuroda 0:13a5d365ba16 179 /** generic constructor from expression of the diagonal coefficients */
ykuroda 0:13a5d365ba16 180 template<typename OtherDerived>
ykuroda 0:13a5d365ba16 181 explicit inline DiagonalMatrix(const MatrixBase<OtherDerived>& other) : m_diagonal(other)
ykuroda 0:13a5d365ba16 182 {}
ykuroda 0:13a5d365ba16 183
ykuroda 0:13a5d365ba16 184 /** Copy operator. */
ykuroda 0:13a5d365ba16 185 template<typename OtherDerived>
ykuroda 0:13a5d365ba16 186 DiagonalMatrix& operator=(const DiagonalBase<OtherDerived>& other)
ykuroda 0:13a5d365ba16 187 {
ykuroda 0:13a5d365ba16 188 m_diagonal = other.diagonal();
ykuroda 0:13a5d365ba16 189 return *this;
ykuroda 0:13a5d365ba16 190 }
ykuroda 0:13a5d365ba16 191
ykuroda 0:13a5d365ba16 192 #ifndef EIGEN_PARSED_BY_DOXYGEN
ykuroda 0:13a5d365ba16 193 /** This is a special case of the templated operator=. Its purpose is to
ykuroda 0:13a5d365ba16 194 * prevent a default operator= from hiding the templated operator=.
ykuroda 0:13a5d365ba16 195 */
ykuroda 0:13a5d365ba16 196 DiagonalMatrix& operator=(const DiagonalMatrix& other)
ykuroda 0:13a5d365ba16 197 {
ykuroda 0:13a5d365ba16 198 m_diagonal = other.diagonal();
ykuroda 0:13a5d365ba16 199 return *this;
ykuroda 0:13a5d365ba16 200 }
ykuroda 0:13a5d365ba16 201 #endif
ykuroda 0:13a5d365ba16 202
ykuroda 0:13a5d365ba16 203 /** Resizes to given size. */
ykuroda 0:13a5d365ba16 204 inline void resize(Index size) { m_diagonal.resize(size); }
ykuroda 0:13a5d365ba16 205 /** Sets all coefficients to zero. */
ykuroda 0:13a5d365ba16 206 inline void setZero() { m_diagonal.setZero(); }
ykuroda 0:13a5d365ba16 207 /** Resizes and sets all coefficients to zero. */
ykuroda 0:13a5d365ba16 208 inline void setZero(Index size) { m_diagonal.setZero(size); }
ykuroda 0:13a5d365ba16 209 /** Sets this matrix to be the identity matrix of the current size. */
ykuroda 0:13a5d365ba16 210 inline void setIdentity() { m_diagonal.setOnes(); }
ykuroda 0:13a5d365ba16 211 /** Sets this matrix to be the identity matrix of the given size. */
ykuroda 0:13a5d365ba16 212 inline void setIdentity(Index size) { m_diagonal.setOnes(size); }
ykuroda 0:13a5d365ba16 213 };
ykuroda 0:13a5d365ba16 214
ykuroda 0:13a5d365ba16 215 /** \class DiagonalWrapper
ykuroda 0:13a5d365ba16 216 * \ingroup Core_Module
ykuroda 0:13a5d365ba16 217 *
ykuroda 0:13a5d365ba16 218 * \brief Expression of a diagonal matrix
ykuroda 0:13a5d365ba16 219 *
ykuroda 0:13a5d365ba16 220 * \param _DiagonalVectorType the type of the vector of diagonal coefficients
ykuroda 0:13a5d365ba16 221 *
ykuroda 0:13a5d365ba16 222 * This class is an expression of a diagonal matrix, but not storing its own vector of diagonal coefficients,
ykuroda 0:13a5d365ba16 223 * instead wrapping an existing vector expression. It is the return type of MatrixBase::asDiagonal()
ykuroda 0:13a5d365ba16 224 * and most of the time this is the only way that it is used.
ykuroda 0:13a5d365ba16 225 *
ykuroda 0:13a5d365ba16 226 * \sa class DiagonalMatrix, class DiagonalBase, MatrixBase::asDiagonal()
ykuroda 0:13a5d365ba16 227 */
ykuroda 0:13a5d365ba16 228
ykuroda 0:13a5d365ba16 229 namespace internal {
ykuroda 0:13a5d365ba16 230 template<typename _DiagonalVectorType>
ykuroda 0:13a5d365ba16 231 struct traits<DiagonalWrapper<_DiagonalVectorType> >
ykuroda 0:13a5d365ba16 232 {
ykuroda 0:13a5d365ba16 233 typedef _DiagonalVectorType DiagonalVectorType;
ykuroda 0:13a5d365ba16 234 typedef typename DiagonalVectorType::Scalar Scalar;
ykuroda 0:13a5d365ba16 235 typedef typename DiagonalVectorType::Index Index;
ykuroda 0:13a5d365ba16 236 typedef typename DiagonalVectorType::StorageKind StorageKind;
ykuroda 0:13a5d365ba16 237 enum {
ykuroda 0:13a5d365ba16 238 RowsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 239 ColsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 240 MaxRowsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 241 MaxColsAtCompileTime = DiagonalVectorType::SizeAtCompileTime,
ykuroda 0:13a5d365ba16 242 Flags = traits<DiagonalVectorType>::Flags & LvalueBit
ykuroda 0:13a5d365ba16 243 };
ykuroda 0:13a5d365ba16 244 };
ykuroda 0:13a5d365ba16 245 }
ykuroda 0:13a5d365ba16 246
ykuroda 0:13a5d365ba16 247 template<typename _DiagonalVectorType>
ykuroda 0:13a5d365ba16 248 class DiagonalWrapper
ykuroda 0:13a5d365ba16 249 : public DiagonalBase<DiagonalWrapper<_DiagonalVectorType> >, internal::no_assignment_operator
ykuroda 0:13a5d365ba16 250 {
ykuroda 0:13a5d365ba16 251 public:
ykuroda 0:13a5d365ba16 252 #ifndef EIGEN_PARSED_BY_DOXYGEN
ykuroda 0:13a5d365ba16 253 typedef _DiagonalVectorType DiagonalVectorType;
ykuroda 0:13a5d365ba16 254 typedef DiagonalWrapper Nested;
ykuroda 0:13a5d365ba16 255 #endif
ykuroda 0:13a5d365ba16 256
ykuroda 0:13a5d365ba16 257 /** Constructor from expression of diagonal coefficients to wrap. */
ykuroda 0:13a5d365ba16 258 inline DiagonalWrapper(DiagonalVectorType& a_diagonal) : m_diagonal(a_diagonal) {}
ykuroda 0:13a5d365ba16 259
ykuroda 0:13a5d365ba16 260 /** \returns a const reference to the wrapped expression of diagonal coefficients. */
ykuroda 0:13a5d365ba16 261 const DiagonalVectorType& diagonal() const { return m_diagonal; }
ykuroda 0:13a5d365ba16 262
ykuroda 0:13a5d365ba16 263 protected:
ykuroda 0:13a5d365ba16 264 typename DiagonalVectorType::Nested m_diagonal;
ykuroda 0:13a5d365ba16 265 };
ykuroda 0:13a5d365ba16 266
ykuroda 0:13a5d365ba16 267 /** \returns a pseudo-expression of a diagonal matrix with *this as vector of diagonal coefficients
ykuroda 0:13a5d365ba16 268 *
ykuroda 0:13a5d365ba16 269 * \only_for_vectors
ykuroda 0:13a5d365ba16 270 *
ykuroda 0:13a5d365ba16 271 * Example: \include MatrixBase_asDiagonal.cpp
ykuroda 0:13a5d365ba16 272 * Output: \verbinclude MatrixBase_asDiagonal.out
ykuroda 0:13a5d365ba16 273 *
ykuroda 0:13a5d365ba16 274 * \sa class DiagonalWrapper, class DiagonalMatrix, diagonal(), isDiagonal()
ykuroda 0:13a5d365ba16 275 **/
ykuroda 0:13a5d365ba16 276 template<typename Derived>
ykuroda 0:13a5d365ba16 277 inline const DiagonalWrapper<const Derived>
ykuroda 0:13a5d365ba16 278 MatrixBase<Derived>::asDiagonal() const
ykuroda 0:13a5d365ba16 279 {
ykuroda 0:13a5d365ba16 280 return derived();
ykuroda 0:13a5d365ba16 281 }
ykuroda 0:13a5d365ba16 282
ykuroda 0:13a5d365ba16 283 /** \returns true if *this is approximately equal to a diagonal matrix,
ykuroda 0:13a5d365ba16 284 * within the precision given by \a prec.
ykuroda 0:13a5d365ba16 285 *
ykuroda 0:13a5d365ba16 286 * Example: \include MatrixBase_isDiagonal.cpp
ykuroda 0:13a5d365ba16 287 * Output: \verbinclude MatrixBase_isDiagonal.out
ykuroda 0:13a5d365ba16 288 *
ykuroda 0:13a5d365ba16 289 * \sa asDiagonal()
ykuroda 0:13a5d365ba16 290 */
ykuroda 0:13a5d365ba16 291 template<typename Derived>
ykuroda 0:13a5d365ba16 292 bool MatrixBase<Derived>::isDiagonal(const RealScalar& prec) const
ykuroda 0:13a5d365ba16 293 {
ykuroda 0:13a5d365ba16 294 using std::abs;
ykuroda 0:13a5d365ba16 295 if(cols() != rows()) return false;
ykuroda 0:13a5d365ba16 296 RealScalar maxAbsOnDiagonal = static_cast<RealScalar>(-1);
ykuroda 0:13a5d365ba16 297 for(Index j = 0; j < cols(); ++j)
ykuroda 0:13a5d365ba16 298 {
ykuroda 0:13a5d365ba16 299 RealScalar absOnDiagonal = abs(coeff(j,j));
ykuroda 0:13a5d365ba16 300 if(absOnDiagonal > maxAbsOnDiagonal) maxAbsOnDiagonal = absOnDiagonal;
ykuroda 0:13a5d365ba16 301 }
ykuroda 0:13a5d365ba16 302 for(Index j = 0; j < cols(); ++j)
ykuroda 0:13a5d365ba16 303 for(Index i = 0; i < j; ++i)
ykuroda 0:13a5d365ba16 304 {
ykuroda 0:13a5d365ba16 305 if(!internal::isMuchSmallerThan(coeff(i, j), maxAbsOnDiagonal, prec)) return false;
ykuroda 0:13a5d365ba16 306 if(!internal::isMuchSmallerThan(coeff(j, i), maxAbsOnDiagonal, prec)) return false;
ykuroda 0:13a5d365ba16 307 }
ykuroda 0:13a5d365ba16 308 return true;
ykuroda 0:13a5d365ba16 309 }
ykuroda 0:13a5d365ba16 310
ykuroda 0:13a5d365ba16 311 } // end namespace Eigen
ykuroda 0:13a5d365ba16 312
ykuroda 0:13a5d365ba16 313 #endif // EIGEN_DIAGONALMATRIX_H