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109 lines
3.5 KiB
C++
109 lines
3.5 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra. Eigen itself is part of the KDE project.
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//
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// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
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//
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// Eigen is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 3 of the License, or (at your option) any later version.
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//
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// Alternatively, you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of
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// the License, or (at your option) any later version.
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//
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// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License and a copy of the GNU General Public License along with
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// Eigen. If not, see <http://www.gnu.org/licenses/>.
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#ifndef EIGEN_DIAGONALCOEFFS_H
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#define EIGEN_DIAGONALCOEFFS_H
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/** \class DiagonalCoeffs
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*
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* \brief Expression of the main diagonal of a square matrix
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*
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* \param MatrixType the type of the object in which we are taking the main diagonal
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*
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* This class represents an expression of the main diagonal of a square matrix.
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* It is the return type of MatrixBase::diagonal() and most of the time this is
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* the only way it is used.
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*
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* \sa MatrixBase::diagonal()
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*/
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template<typename MatrixType>
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struct ei_traits<DiagonalCoeffs<MatrixType> >
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{
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typedef typename MatrixType::Scalar Scalar;
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enum {
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RowsAtCompileTime = MatrixType::SizeAtCompileTime == Dynamic ? Dynamic
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: EIGEN_ENUM_MIN(MatrixType::RowsAtCompileTime,
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MatrixType::ColsAtCompileTime),
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ColsAtCompileTime = 1,
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MaxRowsAtCompileTime = MatrixType::MaxSizeAtCompileTime == Dynamic ? Dynamic
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: EIGEN_ENUM_MIN(MatrixType::MaxRowsAtCompileTime,
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MatrixType::MaxColsAtCompileTime),
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MaxColsAtCompileTime = 1
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};
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};
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template<typename MatrixType> class DiagonalCoeffs
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: public MatrixBase<DiagonalCoeffs<MatrixType> >
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{
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public:
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EIGEN_GENERIC_PUBLIC_INTERFACE(DiagonalCoeffs)
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DiagonalCoeffs(const MatrixType& matrix) : m_matrix(matrix) {}
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EIGEN_INHERIT_ASSIGNMENT_OPERATORS(DiagonalCoeffs)
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private:
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int _rows() const { return std::min(m_matrix.rows(), m_matrix.cols()); }
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int _cols() const { return 1; }
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Scalar& _coeffRef(int row, int)
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{
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return m_matrix.const_cast_derived().coeffRef(row, row);
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}
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Scalar _coeff(int row, int) const
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{
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return m_matrix.coeff(row, row);
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}
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protected:
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const typename MatrixType::XprCopy m_matrix;
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};
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/** \returns an expression of the main diagonal of *this, which must be a square matrix.
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*
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* Example: \include MatrixBase_diagonal.cpp
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* Output: \verbinclude MatrixBase_diagonal.out
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*
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* \sa class DiagonalCoeffs */
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template<typename Derived>
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DiagonalCoeffs<Derived>
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MatrixBase<Derived>::diagonal()
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{
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return DiagonalCoeffs<Derived>(derived());
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}
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/** This is the const version of diagonal(). */
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template<typename Derived>
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const DiagonalCoeffs<Derived>
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MatrixBase<Derived>::diagonal() const
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{
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return DiagonalCoeffs<Derived>(derived());
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}
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#endif // EIGEN_DIAGONALCOEFFS_H
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