chromium/third_party/eigen3/src/Eigen/src/Core/Diagonal.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2007-2009 Benoit Jacob <[email protected]>
// Copyright (C) 2009-2010 Gael Guennebaud <[email protected]>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_DIAGONAL_H
#define EIGEN_DIAGONAL_H

// IWYU pragma: private
#include "./InternalHeaderCheck.h"

namespace Eigen {

/** \class Diagonal
 * \ingroup Core_Module
 *
 * \brief Expression of a diagonal/subdiagonal/superdiagonal in a matrix
 *
 * \tparam MatrixType the type of the object in which we are taking a sub/main/super diagonal
 * \tparam DiagIndex the index of the sub/super diagonal. The default is 0 and it means the main diagonal.
 *              A positive value means a superdiagonal, a negative value means a subdiagonal.
 *              You can also use DynamicIndex so the index can be set at runtime.
 *
 * The matrix is not required to be square.
 *
 * This class represents an expression of the main diagonal, or any sub/super diagonal
 * of a square matrix. It is the return type of MatrixBase::diagonal() and MatrixBase::diagonal(Index) and most of the
 * time this is the only way it is used.
 *
 * \sa MatrixBase::diagonal(), MatrixBase::diagonal(Index)
 */

namespace internal {
traits<Diagonal<MatrixType, DiagIndex>>;
}  // namespace internal

template <typename MatrixType, int DiagIndex_>
class Diagonal : public internal::dense_xpr_base<Diagonal<MatrixType, DiagIndex_> >::type { … };

/** \returns an expression of the main diagonal of the matrix \c *this
 *
 * \c *this is not required to be square.
 *
 * Example: \include MatrixBase_diagonal.cpp
 * Output: \verbinclude MatrixBase_diagonal.out
 *
 * \sa class Diagonal */
template <typename Derived>
EIGEN_DEVICE_FUNC inline typename MatrixBase<Derived>::DiagonalReturnType MatrixBase<Derived>::diagonal() { … }

/** This is the const version of diagonal(). */
template <typename Derived>
EIGEN_DEVICE_FUNC inline const typename MatrixBase<Derived>::ConstDiagonalReturnType MatrixBase<Derived>::diagonal()
    const { … }

/** \returns an expression of the \a DiagIndex-th sub or super diagonal of the matrix \c *this
 *
 * \c *this is not required to be square.
 *
 * The template parameter \a DiagIndex represent a super diagonal if \a DiagIndex > 0
 * and a sub diagonal otherwise. \a DiagIndex == 0 is equivalent to the main diagonal.
 *
 * Example: \include MatrixBase_diagonal_int.cpp
 * Output: \verbinclude MatrixBase_diagonal_int.out
 *
 * \sa MatrixBase::diagonal(), class Diagonal */
template <typename Derived>
EIGEN_DEVICE_FUNC inline Diagonal<Derived, DynamicIndex> MatrixBase<Derived>::diagonal(Index index) { … }

/** This is the const version of diagonal(Index). */
template <typename Derived>
EIGEN_DEVICE_FUNC inline const Diagonal<const Derived, DynamicIndex> MatrixBase<Derived>::diagonal(Index index) const { … }

/** \returns an expression of the \a DiagIndex-th sub or super diagonal of the matrix \c *this
 *
 * \c *this is not required to be square.
 *
 * The template parameter \a DiagIndex represent a super diagonal if \a DiagIndex > 0
 * and a sub diagonal otherwise. \a DiagIndex == 0 is equivalent to the main diagonal.
 *
 * Example: \include MatrixBase_diagonal_template_int.cpp
 * Output: \verbinclude MatrixBase_diagonal_template_int.out
 *
 * \sa MatrixBase::diagonal(), class Diagonal */
template <typename Derived>
template <int Index_>
EIGEN_DEVICE_FUNC inline Diagonal<Derived, Index_> MatrixBase<Derived>::diagonal() { … }

/** This is the const version of diagonal<int>(). */
template <typename Derived>
template <int Index_>
EIGEN_DEVICE_FUNC inline const Diagonal<const Derived, Index_> MatrixBase<Derived>::diagonal() const { … }

}  // end namespace Eigen

#endif  // EIGEN_DIAGONAL_H