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

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Benoit Jacob <[email protected]>
// Copyright (C) 2008-2009 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_TRIANGULARMATRIX_H
#define EIGEN_TRIANGULARMATRIX_H

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

namespace Eigen {

namespace internal {

template <int Side, typename TriangularType, typename Rhs>
struct triangular_solve_retval;

}

/** \class TriangularBase
 * \ingroup Core_Module
 *
 * \brief Base class for triangular part in a matrix
 */
template <typename Derived>
class TriangularBase : public EigenBase<Derived> {};

/** \class TriangularView
 * \ingroup Core_Module
 *
 * \brief Expression of a triangular part in a matrix
 *
 * \tparam MatrixType the type of the object in which we are taking the triangular part
 * \tparam Mode the kind of triangular matrix expression to construct. Can be #Upper,
 *             #Lower, #UnitUpper, #UnitLower, #StrictlyUpper, or #StrictlyLower.
 *             This is in fact a bit field; it must have either #Upper or #Lower,
 *             and additionally it may have #UnitDiag or #ZeroDiag or neither.
 *
 * This class represents a triangular part of a matrix, not necessarily square. Strictly speaking, for rectangular
 * matrices one should speak of "trapezoid" parts. This class is the return type
 * of MatrixBase::triangularView() and SparseMatrixBase::triangularView(), and most of the time this is the only way it
 * is used.
 *
 * \sa MatrixBase::triangularView()
 */
namespace internal {
traits<TriangularView<MatrixType, Mode_>>;
}  // namespace internal

template <typename MatrixType_, unsigned int Mode_, typename StorageKind>
class TriangularViewImpl;

template <typename MatrixType_, unsigned int Mode_>
class TriangularView
    : public TriangularViewImpl<MatrixType_, Mode_, typename internal::traits<MatrixType_>::StorageKind> {};

/** \ingroup Core_Module
 *
 * \brief Base class for a triangular part in a \b dense matrix
 *
 * This class is an abstract base class of class TriangularView, and objects of type TriangularViewImpl cannot be
 * instantiated. It extends class TriangularView with additional methods which available for dense expressions only.
 *
 * \sa class TriangularView, MatrixBase::triangularView()
 */
TriangularViewImpl<MatrixType_, Mode_, Dense>;

/***************************************************************************
 * Implementation of triangular evaluation/assignment
 ***************************************************************************/

#ifndef EIGEN_PARSED_BY_DOXYGEN
// FIXME should we keep that possibility
template <typename MatrixType, unsigned int Mode>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC inline TriangularView<MatrixType, Mode>& TriangularViewImpl<MatrixType, Mode, Dense>::operator=(
    const MatrixBase<OtherDerived>& other) {}

// FIXME should we keep that possibility
template <typename MatrixType, unsigned int Mode>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC void TriangularViewImpl<MatrixType, Mode, Dense>::lazyAssign(const MatrixBase<OtherDerived>& other) {}

template <typename MatrixType, unsigned int Mode>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC inline TriangularView<MatrixType, Mode>& TriangularViewImpl<MatrixType, Mode, Dense>::operator=(
    const TriangularBase<OtherDerived>& other) {}

template <typename MatrixType, unsigned int Mode>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC void TriangularViewImpl<MatrixType, Mode, Dense>::lazyAssign(
    const TriangularBase<OtherDerived>& other) {}
#endif

/***************************************************************************
 * Implementation of TriangularBase methods
 ***************************************************************************/

/** Assigns a triangular or selfadjoint matrix to a dense matrix.
 * If the matrix is triangular, the opposite part is set to zero. */
template <typename Derived>
template <typename DenseDerived>
EIGEN_DEVICE_FUNC void TriangularBase<Derived>::evalTo(MatrixBase<DenseDerived>& other) const {}

/***************************************************************************
 * Implementation of TriangularView methods
 ***************************************************************************/

/***************************************************************************
 * Implementation of MatrixBase methods
 ***************************************************************************/

/**
 * \returns an expression of a triangular view extracted from the current matrix
 *
 * The parameter \a Mode can have the following values: \c #Upper, \c #StrictlyUpper, \c #UnitUpper,
 * \c #Lower, \c #StrictlyLower, \c #UnitLower.
 *
 * Example: \include MatrixBase_triangularView.cpp
 * Output: \verbinclude MatrixBase_triangularView.out
 *
 * \sa class TriangularView
 */
template <typename Derived>
template <unsigned int Mode>
EIGEN_DEVICE_FUNC typename MatrixBase<Derived>::template TriangularViewReturnType<Mode>::Type
MatrixBase<Derived>::triangularView() {}

/** This is the const version of MatrixBase::triangularView() */
template <typename Derived>
template <unsigned int Mode>
EIGEN_DEVICE_FUNC typename MatrixBase<Derived>::template ConstTriangularViewReturnType<Mode>::Type
MatrixBase<Derived>::triangularView() const {}

/** \returns true if *this is approximately equal to an upper triangular matrix,
 *          within the precision given by \a prec.
 *
 * \sa isLowerTriangular()
 */
template <typename Derived>
bool MatrixBase<Derived>::isUpperTriangular(const RealScalar& prec) const {}

/** \returns true if *this is approximately equal to a lower triangular matrix,
 *          within the precision given by \a prec.
 *
 * \sa isUpperTriangular()
 */
template <typename Derived>
bool MatrixBase<Derived>::isLowerTriangular(const RealScalar& prec) const {}

/***************************************************************************
****************************************************************************
* Evaluators and Assignment of triangular expressions
***************************************************************************
***************************************************************************/

namespace internal {

// TODO currently a triangular expression has the form TriangularView<.,.>
//      in the future triangular-ness should be defined by the expression traits
//      such that Transpose<TriangularView<.,.> > is valid. (currently TriangularBase::transpose() is overloaded to make
//      it work)
evaluator_traits<TriangularView<MatrixType, Mode>>;

unary_evaluator<TriangularView<MatrixType, Mode>, IndexBased>;

// Additional assignment kinds:
struct Triangular2Triangular {};
struct Triangular2Dense {};
struct Dense2Triangular {};

template <typename Kernel, unsigned int Mode, int UnrollCount, bool ClearOpposite>
struct triangular_assignment_loop;

/** \internal Specialization of the dense assignment kernel for triangular matrices.
 * The main difference is that the triangular, diagonal, and opposite parts are processed through three different
 * functions. \tparam UpLo must be either Lower or Upper \tparam Mode must be either 0, UnitDiag, ZeroDiag, or
 * SelfAdjoint
 */
template <int UpLo, int Mode, int SetOpposite, typename DstEvaluatorTypeT, typename SrcEvaluatorTypeT, typename Functor,
          int Version = Specialized>
class triangular_dense_assignment_kernel
    : public generic_dense_assignment_kernel<DstEvaluatorTypeT, SrcEvaluatorTypeT, Functor, Version> {};

template <int Mode, bool SetOpposite, typename DstXprType, typename SrcXprType, typename Functor>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void call_triangular_assignment_loop(DstXprType& dst, const SrcXprType& src,
                                                                           const Functor& func) {}

template <int Mode, bool SetOpposite, typename DstXprType, typename SrcXprType>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void call_triangular_assignment_loop(DstXprType& dst, const SrcXprType& src) {}

template <>
struct AssignmentKind<TriangularShape, TriangularShape> {};
template <>
struct AssignmentKind<DenseShape, TriangularShape> {};
template <>
struct AssignmentKind<TriangularShape, DenseShape> {};

Assignment<DstXprType, SrcXprType, Functor, Triangular2Triangular>;

Assignment<DstXprType, SrcXprType, Functor, Triangular2Dense>;

Assignment<DstXprType, SrcXprType, Functor, Dense2Triangular>;

template <typename Kernel, unsigned int Mode, int UnrollCount, bool SetOpposite>
struct triangular_assignment_loop {};

// prevent buggy user code from causing an infinite recursion
triangular_assignment_loop<Kernel, Mode, 0, SetOpposite>;

// TODO: experiment with a recursive assignment procedure splitting the current
//       triangular part into one rectangular and two triangular parts.

triangular_assignment_loop<Kernel, Mode, Dynamic, SetOpposite>;

}  // end namespace internal

/** Assigns a triangular or selfadjoint matrix to a dense matrix.
 * If the matrix is triangular, the opposite part is set to zero. */
template <typename Derived>
template <typename DenseDerived>
EIGEN_DEVICE_FUNC void TriangularBase<Derived>::evalToLazy(MatrixBase<DenseDerived>& other) const {}

namespace internal {

// Triangular = Product
Assignment<DstXprType, Product<Lhs, Rhs, DefaultProduct>, internal::assign_op<Scalar, typename Product<Lhs, Rhs, DefaultProduct>::Scalar>, Dense2Triangular>;

// Triangular += Product
Assignment<DstXprType, Product<Lhs, Rhs, DefaultProduct>, internal::add_assign_op<Scalar, typename Product<Lhs, Rhs, DefaultProduct>::Scalar>, Dense2Triangular>;

// Triangular -= Product
Assignment<DstXprType, Product<Lhs, Rhs, DefaultProduct>, internal::sub_assign_op<Scalar, typename Product<Lhs, Rhs, DefaultProduct>::Scalar>, Dense2Triangular>;

}  // end namespace internal

}  // end namespace Eigen

#endif  // EIGEN_TRIANGULARMATRIX_H