[136] | 1 | // This file is part of Eigen, a lightweight C++ template library
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| 2 | // for linear algebra.
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| 3 | //
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| 4 | // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
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| 5 | // Copyright (C) 2009 Ricard Marxer <email@ricardmarxer.com>
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| 6 | // Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
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| 7 | //
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| 8 | // This Source Code Form is subject to the terms of the Mozilla
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| 9 | // Public License v. 2.0. If a copy of the MPL was not distributed
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| 10 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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| 11 |
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| 12 | #ifndef EIGEN_REVERSE_H
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| 13 | #define EIGEN_REVERSE_H
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| 14 |
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| 15 | namespace Eigen {
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| 16 |
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| 17 | /** \class Reverse
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| 18 | * \ingroup Core_Module
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| 19 | *
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| 20 | * \brief Expression of the reverse of a vector or matrix
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| 21 | *
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| 22 | * \param MatrixType the type of the object of which we are taking the reverse
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| 23 | *
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| 24 | * This class represents an expression of the reverse of a vector.
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| 25 | * It is the return type of MatrixBase::reverse() and VectorwiseOp::reverse()
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| 26 | * and most of the time this is the only way it is used.
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| 27 | *
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| 28 | * \sa MatrixBase::reverse(), VectorwiseOp::reverse()
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| 29 | */
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| 30 |
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| 31 | namespace internal {
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| 32 |
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| 33 | template<typename MatrixType, int Direction>
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| 34 | struct traits<Reverse<MatrixType, Direction> >
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| 35 | : traits<MatrixType>
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| 36 | {
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| 37 | typedef typename MatrixType::Scalar Scalar;
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| 38 | typedef typename traits<MatrixType>::StorageKind StorageKind;
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| 39 | typedef typename traits<MatrixType>::XprKind XprKind;
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| 40 | typedef typename nested<MatrixType>::type MatrixTypeNested;
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| 41 | typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
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| 42 | enum {
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| 43 | RowsAtCompileTime = MatrixType::RowsAtCompileTime,
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| 44 | ColsAtCompileTime = MatrixType::ColsAtCompileTime,
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| 45 | MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
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| 46 | MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime,
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| 47 |
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| 48 | // let's enable LinearAccess only with vectorization because of the product overhead
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| 49 | LinearAccess = ( (Direction==BothDirections) && (int(_MatrixTypeNested::Flags)&PacketAccessBit) )
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| 50 | ? LinearAccessBit : 0,
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| 51 |
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| 52 | Flags = int(_MatrixTypeNested::Flags) & (HereditaryBits | LvalueBit | PacketAccessBit | LinearAccess),
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| 53 |
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| 54 | CoeffReadCost = _MatrixTypeNested::CoeffReadCost
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| 55 | };
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| 56 | };
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| 57 |
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| 58 | template<typename PacketScalar, bool ReversePacket> struct reverse_packet_cond
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| 59 | {
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| 60 | static inline PacketScalar run(const PacketScalar& x) { return preverse(x); }
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| 61 | };
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| 62 |
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| 63 | template<typename PacketScalar> struct reverse_packet_cond<PacketScalar,false>
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| 64 | {
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| 65 | static inline PacketScalar run(const PacketScalar& x) { return x; }
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| 66 | };
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| 67 |
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| 68 | } // end namespace internal
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| 69 |
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| 70 | template<typename MatrixType, int Direction> class Reverse
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| 71 | : public internal::dense_xpr_base< Reverse<MatrixType, Direction> >::type
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| 72 | {
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| 73 | public:
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| 74 |
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| 75 | typedef typename internal::dense_xpr_base<Reverse>::type Base;
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| 76 | EIGEN_DENSE_PUBLIC_INTERFACE(Reverse)
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| 77 | using Base::IsRowMajor;
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| 78 |
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| 79 | // next line is necessary because otherwise const version of operator()
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| 80 | // is hidden by non-const version defined in this file
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| 81 | using Base::operator();
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| 82 |
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| 83 | protected:
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| 84 | enum {
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| 85 | PacketSize = internal::packet_traits<Scalar>::size,
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| 86 | IsColMajor = !IsRowMajor,
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| 87 | ReverseRow = (Direction == Vertical) || (Direction == BothDirections),
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| 88 | ReverseCol = (Direction == Horizontal) || (Direction == BothDirections),
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| 89 | OffsetRow = ReverseRow && IsColMajor ? PacketSize : 1,
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| 90 | OffsetCol = ReverseCol && IsRowMajor ? PacketSize : 1,
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| 91 | ReversePacket = (Direction == BothDirections)
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| 92 | || ((Direction == Vertical) && IsColMajor)
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| 93 | || ((Direction == Horizontal) && IsRowMajor)
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| 94 | };
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| 95 | typedef internal::reverse_packet_cond<PacketScalar,ReversePacket> reverse_packet;
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| 96 | public:
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| 97 |
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| 98 | inline Reverse(const MatrixType& matrix) : m_matrix(matrix) { }
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| 99 |
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| 100 | EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Reverse)
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| 101 |
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| 102 | inline Index rows() const { return m_matrix.rows(); }
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| 103 | inline Index cols() const { return m_matrix.cols(); }
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| 104 |
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| 105 | inline Index innerStride() const
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| 106 | {
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| 107 | return -m_matrix.innerStride();
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| 108 | }
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| 109 |
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| 110 | inline Scalar& operator()(Index row, Index col)
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| 111 | {
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| 112 | eigen_assert(row >= 0 && row < rows() && col >= 0 && col < cols());
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| 113 | return coeffRef(row, col);
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| 114 | }
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| 115 |
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| 116 | inline Scalar& coeffRef(Index row, Index col)
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| 117 | {
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| 118 | return m_matrix.const_cast_derived().coeffRef(ReverseRow ? m_matrix.rows() - row - 1 : row,
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| 119 | ReverseCol ? m_matrix.cols() - col - 1 : col);
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| 120 | }
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| 121 |
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| 122 | inline CoeffReturnType coeff(Index row, Index col) const
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| 123 | {
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| 124 | return m_matrix.coeff(ReverseRow ? m_matrix.rows() - row - 1 : row,
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| 125 | ReverseCol ? m_matrix.cols() - col - 1 : col);
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| 126 | }
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| 127 |
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| 128 | inline CoeffReturnType coeff(Index index) const
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| 129 | {
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| 130 | return m_matrix.coeff(m_matrix.size() - index - 1);
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| 131 | }
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| 132 |
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| 133 | inline Scalar& coeffRef(Index index)
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| 134 | {
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| 135 | return m_matrix.const_cast_derived().coeffRef(m_matrix.size() - index - 1);
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| 136 | }
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| 137 |
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| 138 | inline Scalar& operator()(Index index)
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| 139 | {
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| 140 | eigen_assert(index >= 0 && index < m_matrix.size());
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| 141 | return coeffRef(index);
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| 142 | }
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| 143 |
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| 144 | template<int LoadMode>
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| 145 | inline const PacketScalar packet(Index row, Index col) const
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| 146 | {
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| 147 | return reverse_packet::run(m_matrix.template packet<LoadMode>(
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| 148 | ReverseRow ? m_matrix.rows() - row - OffsetRow : row,
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| 149 | ReverseCol ? m_matrix.cols() - col - OffsetCol : col));
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| 150 | }
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| 151 |
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| 152 | template<int LoadMode>
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| 153 | inline void writePacket(Index row, Index col, const PacketScalar& x)
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| 154 | {
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| 155 | m_matrix.const_cast_derived().template writePacket<LoadMode>(
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| 156 | ReverseRow ? m_matrix.rows() - row - OffsetRow : row,
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| 157 | ReverseCol ? m_matrix.cols() - col - OffsetCol : col,
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| 158 | reverse_packet::run(x));
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| 159 | }
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| 160 |
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| 161 | template<int LoadMode>
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| 162 | inline const PacketScalar packet(Index index) const
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| 163 | {
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| 164 | return internal::preverse(m_matrix.template packet<LoadMode>( m_matrix.size() - index - PacketSize ));
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| 165 | }
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| 166 |
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| 167 | template<int LoadMode>
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| 168 | inline void writePacket(Index index, const PacketScalar& x)
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| 169 | {
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| 170 | m_matrix.const_cast_derived().template writePacket<LoadMode>(m_matrix.size() - index - PacketSize, internal::preverse(x));
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| 171 | }
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| 172 |
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| 173 | const typename internal::remove_all<typename MatrixType::Nested>::type&
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| 174 | nestedExpression() const
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| 175 | {
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| 176 | return m_matrix;
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| 177 | }
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| 178 |
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| 179 | protected:
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| 180 | typename MatrixType::Nested m_matrix;
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| 181 | };
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| 182 |
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| 183 | /** \returns an expression of the reverse of *this.
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| 184 | *
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| 185 | * Example: \include MatrixBase_reverse.cpp
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| 186 | * Output: \verbinclude MatrixBase_reverse.out
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| 187 | *
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| 188 | */
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| 189 | template<typename Derived>
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| 190 | inline typename DenseBase<Derived>::ReverseReturnType
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| 191 | DenseBase<Derived>::reverse()
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| 192 | {
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| 193 | return derived();
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| 194 | }
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| 195 |
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| 196 | /** This is the const version of reverse(). */
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| 197 | template<typename Derived>
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| 198 | inline const typename DenseBase<Derived>::ConstReverseReturnType
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| 199 | DenseBase<Derived>::reverse() const
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| 200 | {
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| 201 | return derived();
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| 202 | }
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| 203 |
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| 204 | /** This is the "in place" version of reverse: it reverses \c *this.
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| 205 | *
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| 206 | * In most cases it is probably better to simply use the reversed expression
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| 207 | * of a matrix. However, when reversing the matrix data itself is really needed,
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| 208 | * then this "in-place" version is probably the right choice because it provides
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| 209 | * the following additional features:
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| 210 | * - less error prone: doing the same operation with .reverse() requires special care:
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| 211 | * \code m = m.reverse().eval(); \endcode
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| 212 | * - this API allows to avoid creating a temporary (the current implementation creates a temporary, but that could be avoided using swap)
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| 213 | * - it allows future optimizations (cache friendliness, etc.)
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| 214 | *
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| 215 | * \sa reverse() */
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| 216 | template<typename Derived>
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| 217 | inline void DenseBase<Derived>::reverseInPlace()
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| 218 | {
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| 219 | derived() = derived().reverse().eval();
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| 220 | }
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| 221 |
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| 222 | } // end namespace Eigen
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| 223 |
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| 224 | #endif // EIGEN_REVERSE_H
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