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Diffstat (limited to 'Eigen/src/Core/Reverse.h')
| -rw-r--r-- | Eigen/src/Core/Reverse.h | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/Eigen/src/Core/Reverse.h b/Eigen/src/Core/Reverse.h new file mode 100644 index 000000000..e30ae3d28 --- /dev/null +++ b/Eigen/src/Core/Reverse.h @@ -0,0 +1,224 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com> +// Copyright (C) 2009 Ricard Marxer <email@ricardmarxer.com> +// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr> +// +// 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_REVERSE_H +#define EIGEN_REVERSE_H + +namespace Eigen { + +/** \class Reverse + * \ingroup Core_Module + * + * \brief Expression of the reverse of a vector or matrix + * + * \param MatrixType the type of the object of which we are taking the reverse + * + * This class represents an expression of the reverse of a vector. + * It is the return type of MatrixBase::reverse() and VectorwiseOp::reverse() + * and most of the time this is the only way it is used. + * + * \sa MatrixBase::reverse(), VectorwiseOp::reverse() + */ + +namespace internal { + +template<typename MatrixType, int Direction> +struct traits<Reverse<MatrixType, Direction> > + : traits<MatrixType> +{ + typedef typename MatrixType::Scalar Scalar; + typedef typename traits<MatrixType>::StorageKind StorageKind; + typedef typename traits<MatrixType>::XprKind XprKind; + typedef typename nested<MatrixType>::type MatrixTypeNested; + typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested; + enum { + RowsAtCompileTime = MatrixType::RowsAtCompileTime, + ColsAtCompileTime = MatrixType::ColsAtCompileTime, + MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime, + MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime, + + // let's enable LinearAccess only with vectorization because of the product overhead + LinearAccess = ( (Direction==BothDirections) && (int(_MatrixTypeNested::Flags)&PacketAccessBit) ) + ? LinearAccessBit : 0, + + Flags = int(_MatrixTypeNested::Flags) & (HereditaryBits | LvalueBit | PacketAccessBit | LinearAccess), + + CoeffReadCost = _MatrixTypeNested::CoeffReadCost + }; +}; + +template<typename PacketScalar, bool ReversePacket> struct reverse_packet_cond +{ + static inline PacketScalar run(const PacketScalar& x) { return preverse(x); } +}; + +template<typename PacketScalar> struct reverse_packet_cond<PacketScalar,false> +{ + static inline PacketScalar run(const PacketScalar& x) { return x; } +}; + +} // end namespace internal + +template<typename MatrixType, int Direction> class Reverse + : public internal::dense_xpr_base< Reverse<MatrixType, Direction> >::type +{ + public: + + typedef typename internal::dense_xpr_base<Reverse>::type Base; + EIGEN_DENSE_PUBLIC_INTERFACE(Reverse) + using Base::IsRowMajor; + + // next line is necessary because otherwise const version of operator() + // is hidden by non-const version defined in this file + using Base::operator(); + + protected: + enum { + PacketSize = internal::packet_traits<Scalar>::size, + IsColMajor = !IsRowMajor, + ReverseRow = (Direction == Vertical) || (Direction == BothDirections), + ReverseCol = (Direction == Horizontal) || (Direction == BothDirections), + OffsetRow = ReverseRow && IsColMajor ? PacketSize : 1, + OffsetCol = ReverseCol && IsRowMajor ? PacketSize : 1, + ReversePacket = (Direction == BothDirections) + || ((Direction == Vertical) && IsColMajor) + || ((Direction == Horizontal) && IsRowMajor) + }; + typedef internal::reverse_packet_cond<PacketScalar,ReversePacket> reverse_packet; + public: + + inline Reverse(const MatrixType& matrix) : m_matrix(matrix) { } + + EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Reverse) + + inline Index rows() const { return m_matrix.rows(); } + inline Index cols() const { return m_matrix.cols(); } + + inline Index innerStride() const + { + return -m_matrix.innerStride(); + } + + inline Scalar& operator()(Index row, Index col) + { + eigen_assert(row >= 0 && row < rows() && col >= 0 && col < cols()); + return coeffRef(row, col); + } + + inline Scalar& coeffRef(Index row, Index col) + { + return m_matrix.const_cast_derived().coeffRef(ReverseRow ? m_matrix.rows() - row - 1 : row, + ReverseCol ? m_matrix.cols() - col - 1 : col); + } + + inline CoeffReturnType coeff(Index row, Index col) const + { + return m_matrix.coeff(ReverseRow ? m_matrix.rows() - row - 1 : row, + ReverseCol ? m_matrix.cols() - col - 1 : col); + } + + inline CoeffReturnType coeff(Index index) const + { + return m_matrix.coeff(m_matrix.size() - index - 1); + } + + inline Scalar& coeffRef(Index index) + { + return m_matrix.const_cast_derived().coeffRef(m_matrix.size() - index - 1); + } + + inline Scalar& operator()(Index index) + { + eigen_assert(index >= 0 && index < m_matrix.size()); + return coeffRef(index); + } + + template<int LoadMode> + inline const PacketScalar packet(Index row, Index col) const + { + return reverse_packet::run(m_matrix.template packet<LoadMode>( + ReverseRow ? m_matrix.rows() - row - OffsetRow : row, + ReverseCol ? m_matrix.cols() - col - OffsetCol : col)); + } + + template<int LoadMode> + inline void writePacket(Index row, Index col, const PacketScalar& x) + { + m_matrix.const_cast_derived().template writePacket<LoadMode>( + ReverseRow ? m_matrix.rows() - row - OffsetRow : row, + ReverseCol ? m_matrix.cols() - col - OffsetCol : col, + reverse_packet::run(x)); + } + + template<int LoadMode> + inline const PacketScalar packet(Index index) const + { + return internal::preverse(m_matrix.template packet<LoadMode>( m_matrix.size() - index - PacketSize )); + } + + template<int LoadMode> + inline void writePacket(Index index, const PacketScalar& x) + { + m_matrix.const_cast_derived().template writePacket<LoadMode>(m_matrix.size() - index - PacketSize, internal::preverse(x)); + } + + const typename internal::remove_all<typename MatrixType::Nested>::type& + nestedExpression() const + { + return m_matrix; + } + + protected: + typename MatrixType::Nested m_matrix; +}; + +/** \returns an expression of the reverse of *this. + * + * Example: \include MatrixBase_reverse.cpp + * Output: \verbinclude MatrixBase_reverse.out + * + */ +template<typename Derived> +inline typename DenseBase<Derived>::ReverseReturnType +DenseBase<Derived>::reverse() +{ + return derived(); +} + +/** This is the const version of reverse(). */ +template<typename Derived> +inline const typename DenseBase<Derived>::ConstReverseReturnType +DenseBase<Derived>::reverse() const +{ + return derived(); +} + +/** This is the "in place" version of reverse: it reverses \c *this. + * + * In most cases it is probably better to simply use the reversed expression + * of a matrix. However, when reversing the matrix data itself is really needed, + * then this "in-place" version is probably the right choice because it provides + * the following additional features: + * - less error prone: doing the same operation with .reverse() requires special care: + * \code m = m.reverse().eval(); \endcode + * - this API allows to avoid creating a temporary (the current implementation creates a temporary, but that could be avoided using swap) + * - it allows future optimizations (cache friendliness, etc.) + * + * \sa reverse() */ +template<typename Derived> +inline void DenseBase<Derived>::reverseInPlace() +{ + derived() = derived().reverse().eval(); +} + +} // end namespace Eigen + +#endif // EIGEN_REVERSE_H |