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Eigen  3.4.0
Reverse.h
1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
5 // Copyright (C) 2009 Ricard Marxer <email@ricardmarxer.com>
6 // Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
7 //
8 // This Source Code Form is subject to the terms of the Mozilla
9 // Public License v. 2.0. If a copy of the MPL was not distributed
10 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
11 
12 #ifndef EIGEN_REVERSE_H
13 #define EIGEN_REVERSE_H
14 
15 namespace Eigen {
16 
17 namespace internal {
18 
19 template<typename MatrixType, int Direction>
20 struct traits<Reverse<MatrixType, Direction> >
21  : traits<MatrixType>
22 {
23  typedef typename MatrixType::Scalar Scalar;
24  typedef typename traits<MatrixType>::StorageKind StorageKind;
25  typedef typename traits<MatrixType>::XprKind XprKind;
26  typedef typename ref_selector<MatrixType>::type MatrixTypeNested;
27  typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
28  enum {
29  RowsAtCompileTime = MatrixType::RowsAtCompileTime,
30  ColsAtCompileTime = MatrixType::ColsAtCompileTime,
31  MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
32  MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime,
33  Flags = _MatrixTypeNested::Flags & (RowMajorBit | LvalueBit)
34  };
35 };
36 
37 template<typename PacketType, bool ReversePacket> struct reverse_packet_cond
38 {
39  static inline PacketType run(const PacketType& x) { return preverse(x); }
40 };
41 
42 template<typename PacketType> struct reverse_packet_cond<PacketType,false>
43 {
44  static inline PacketType run(const PacketType& x) { return x; }
45 };
46 
47 } // end namespace internal
48 
63 template<typename MatrixType, int Direction> class Reverse
64  : public internal::dense_xpr_base< Reverse<MatrixType, Direction> >::type
65 {
66  public:
67 
68  typedef typename internal::dense_xpr_base<Reverse>::type Base;
69  EIGEN_DENSE_PUBLIC_INTERFACE(Reverse)
70  typedef typename internal::remove_all<MatrixType>::type NestedExpression;
71  using Base::IsRowMajor;
72 
73  protected:
74  enum {
75  PacketSize = internal::packet_traits<Scalar>::size,
76  IsColMajor = !IsRowMajor,
77  ReverseRow = (Direction == Vertical) || (Direction == BothDirections),
78  ReverseCol = (Direction == Horizontal) || (Direction == BothDirections),
79  OffsetRow = ReverseRow && IsColMajor ? PacketSize : 1,
80  OffsetCol = ReverseCol && IsRowMajor ? PacketSize : 1,
81  ReversePacket = (Direction == BothDirections)
82  || ((Direction == Vertical) && IsColMajor)
83  || ((Direction == Horizontal) && IsRowMajor)
84  };
85  typedef internal::reverse_packet_cond<PacketScalar,ReversePacket> reverse_packet;
86  public:
87 
88  EIGEN_DEVICE_FUNC explicit inline Reverse(const MatrixType& matrix) : m_matrix(matrix) { }
89 
90  EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Reverse)
91 
92  EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR
93  inline Index rows() const EIGEN_NOEXCEPT { return m_matrix.rows(); }
94  EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR
95  inline Index cols() const EIGEN_NOEXCEPT { return m_matrix.cols(); }
96 
97  EIGEN_DEVICE_FUNC inline Index innerStride() const
98  {
99  return -m_matrix.innerStride();
100  }
101 
102  EIGEN_DEVICE_FUNC const typename internal::remove_all<typename MatrixType::Nested>::type&
103  nestedExpression() const
104  {
105  return m_matrix;
106  }
107 
108  protected:
109  typename MatrixType::Nested m_matrix;
110 };
111 
118 template<typename Derived>
119 EIGEN_DEVICE_FUNC inline typename DenseBase<Derived>::ReverseReturnType
121 {
122  return ReverseReturnType(derived());
123 }
124 
125 
126 //reverse const overload moved DenseBase.h due to a CUDA compiler bug
127 
140 template<typename Derived>
141 EIGEN_DEVICE_FUNC inline void DenseBase<Derived>::reverseInPlace()
142 {
143  if(cols()>rows())
144  {
145  Index half = cols()/2;
146  leftCols(half).swap(rightCols(half).reverse());
147  if((cols()%2)==1)
148  {
149  Index half2 = rows()/2;
150  col(half).head(half2).swap(col(half).tail(half2).reverse());
151  }
152  }
153  else
154  {
155  Index half = rows()/2;
156  topRows(half).swap(bottomRows(half).reverse());
157  if((rows()%2)==1)
158  {
159  Index half2 = cols()/2;
160  row(half).head(half2).swap(row(half).tail(half2).reverse());
161  }
162  }
163 }
164 
165 namespace internal {
166 
167 template<int Direction>
168 struct vectorwise_reverse_inplace_impl;
169 
170 template<>
171 struct vectorwise_reverse_inplace_impl<Vertical>
172 {
173  template<typename ExpressionType>
174  static void run(ExpressionType &xpr)
175  {
176  const int HalfAtCompileTime = ExpressionType::RowsAtCompileTime==Dynamic?Dynamic:ExpressionType::RowsAtCompileTime/2;
177  Index half = xpr.rows()/2;
178  xpr.topRows(fix<HalfAtCompileTime>(half))
179  .swap(xpr.bottomRows(fix<HalfAtCompileTime>(half)).colwise().reverse());
180  }
181 };
182 
183 template<>
184 struct vectorwise_reverse_inplace_impl<Horizontal>
185 {
186  template<typename ExpressionType>
187  static void run(ExpressionType &xpr)
188  {
189  const int HalfAtCompileTime = ExpressionType::ColsAtCompileTime==Dynamic?Dynamic:ExpressionType::ColsAtCompileTime/2;
190  Index half = xpr.cols()/2;
191  xpr.leftCols(fix<HalfAtCompileTime>(half))
192  .swap(xpr.rightCols(fix<HalfAtCompileTime>(half)).rowwise().reverse());
193  }
194 };
195 
196 } // end namespace internal
197 
209 template<typename ExpressionType, int Direction>
211 {
212  internal::vectorwise_reverse_inplace_impl<Direction>::run(m_matrix);
213 }
214 
215 } // end namespace Eigen
216 
217 #endif // EIGEN_REVERSE_H
Definition: Constants.h:264
void reverseInPlace()
Definition: Reverse.h:210
const unsigned int LvalueBit
Definition: Constants.h:144
Namespace containing all symbols from the Eigen library.
Definition: Core:141
const unsigned int RowMajorBit
Definition: Constants.h:66
EIGEN_DEFAULT_DENSE_INDEX_TYPE Index
The Index type as used for the API.
Definition: Meta.h:74
ReverseReturnType reverse()
Definition: Reverse.h:120
Definition: Constants.h:267
Definition: Constants.h:270
Definition: Eigen_Colamd.h:50
void reverseInPlace()
Definition: Reverse.h:141
const int Dynamic
Definition: Constants.h:22
Expression of the reverse of a vector or matrix.
Definition: Reverse.h:63