Diff: src/Core/Reverse.h
- Revision:
- 0:13a5d365ba16
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Core/Reverse.h Thu Oct 13 04:07:23 2016 +0000
@@ -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
\ No newline at end of file