1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
5//
6// This Source Code Form is subject to the terms of the Mozilla
7// Public License v. 2.0. If a copy of the MPL was not distributed
8// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10#ifndef EIGEN_HOMOGENEOUS_H
11#define EIGEN_HOMOGENEOUS_H
12
13namespace Eigen {
14
15/** \geometry_module \ingroup Geometry_Module
16  *
17  * \class Homogeneous
18  *
19  * \brief Expression of one (or a set of) homogeneous vector(s)
20  *
21  * \param MatrixType the type of the object in which we are making homogeneous
22  *
23  * This class represents an expression of one (or a set of) homogeneous vector(s).
24  * It is the return type of MatrixBase::homogeneous() and most of the time
25  * this is the only way it is used.
26  *
27  * \sa MatrixBase::homogeneous()
28  */
29
30namespace internal {
31
32template<typename MatrixType,int Direction>
33struct traits<Homogeneous<MatrixType,Direction> >
34 : traits<MatrixType>
35{
36  typedef typename traits<MatrixType>::StorageKind StorageKind;
37  typedef typename nested<MatrixType>::type MatrixTypeNested;
38  typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
39  enum {
40    RowsPlusOne = (MatrixType::RowsAtCompileTime != Dynamic) ?
41                  int(MatrixType::RowsAtCompileTime) + 1 : Dynamic,
42    ColsPlusOne = (MatrixType::ColsAtCompileTime != Dynamic) ?
43                  int(MatrixType::ColsAtCompileTime) + 1 : Dynamic,
44    RowsAtCompileTime = Direction==Vertical  ?  RowsPlusOne : MatrixType::RowsAtCompileTime,
45    ColsAtCompileTime = Direction==Horizontal ? ColsPlusOne : MatrixType::ColsAtCompileTime,
46    MaxRowsAtCompileTime = RowsAtCompileTime,
47    MaxColsAtCompileTime = ColsAtCompileTime,
48    TmpFlags = _MatrixTypeNested::Flags & HereditaryBits,
49    Flags = ColsAtCompileTime==1 ? (TmpFlags & ~RowMajorBit)
50          : RowsAtCompileTime==1 ? (TmpFlags | RowMajorBit)
51          : TmpFlags,
52    CoeffReadCost = _MatrixTypeNested::CoeffReadCost
53  };
54};
55
56template<typename MatrixType,typename Lhs> struct homogeneous_left_product_impl;
57template<typename MatrixType,typename Rhs> struct homogeneous_right_product_impl;
58
59} // end namespace internal
60
61template<typename MatrixType,int _Direction> class Homogeneous
62  : internal::no_assignment_operator, public MatrixBase<Homogeneous<MatrixType,_Direction> >
63{
64  public:
65
66    enum { Direction = _Direction };
67
68    typedef MatrixBase<Homogeneous> Base;
69    EIGEN_DENSE_PUBLIC_INTERFACE(Homogeneous)
70
71    inline Homogeneous(const MatrixType& matrix)
72      : m_matrix(matrix)
73    {}
74
75    inline Index rows() const { return m_matrix.rows() + (int(Direction)==Vertical   ? 1 : 0); }
76    inline Index cols() const { return m_matrix.cols() + (int(Direction)==Horizontal ? 1 : 0); }
77
78    inline Scalar coeff(Index row, Index col) const
79    {
80      if(  (int(Direction)==Vertical   && row==m_matrix.rows())
81        || (int(Direction)==Horizontal && col==m_matrix.cols()))
82        return Scalar(1);
83      return m_matrix.coeff(row, col);
84    }
85
86    template<typename Rhs>
87    inline const internal::homogeneous_right_product_impl<Homogeneous,Rhs>
88    operator* (const MatrixBase<Rhs>& rhs) const
89    {
90      eigen_assert(int(Direction)==Horizontal);
91      return internal::homogeneous_right_product_impl<Homogeneous,Rhs>(m_matrix,rhs.derived());
92    }
93
94    template<typename Lhs> friend
95    inline const internal::homogeneous_left_product_impl<Homogeneous,Lhs>
96    operator* (const MatrixBase<Lhs>& lhs, const Homogeneous& rhs)
97    {
98      eigen_assert(int(Direction)==Vertical);
99      return internal::homogeneous_left_product_impl<Homogeneous,Lhs>(lhs.derived(),rhs.m_matrix);
100    }
101
102    template<typename Scalar, int Dim, int Mode, int Options> friend
103    inline const internal::homogeneous_left_product_impl<Homogeneous,Transform<Scalar,Dim,Mode,Options> >
104    operator* (const Transform<Scalar,Dim,Mode,Options>& lhs, const Homogeneous& rhs)
105    {
106      eigen_assert(int(Direction)==Vertical);
107      return internal::homogeneous_left_product_impl<Homogeneous,Transform<Scalar,Dim,Mode,Options> >(lhs,rhs.m_matrix);
108    }
109
110  protected:
111    typename MatrixType::Nested m_matrix;
112};
113
114/** \geometry_module
115  *
116  * \return an expression of the equivalent homogeneous vector
117  *
118  * \only_for_vectors
119  *
120  * Example: \include MatrixBase_homogeneous.cpp
121  * Output: \verbinclude MatrixBase_homogeneous.out
122  *
123  * \sa class Homogeneous
124  */
125template<typename Derived>
126inline typename MatrixBase<Derived>::HomogeneousReturnType
127MatrixBase<Derived>::homogeneous() const
128{
129  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
130  return derived();
131}
132
133/** \geometry_module
134  *
135  * \returns a matrix expression of homogeneous column (or row) vectors
136  *
137  * Example: \include VectorwiseOp_homogeneous.cpp
138  * Output: \verbinclude VectorwiseOp_homogeneous.out
139  *
140  * \sa MatrixBase::homogeneous() */
141template<typename ExpressionType, int Direction>
142inline Homogeneous<ExpressionType,Direction>
143VectorwiseOp<ExpressionType,Direction>::homogeneous() const
144{
145  return _expression();
146}
147
148/** \geometry_module
149  *
150  * \returns an expression of the homogeneous normalized vector of \c *this
151  *
152  * Example: \include MatrixBase_hnormalized.cpp
153  * Output: \verbinclude MatrixBase_hnormalized.out
154  *
155  * \sa VectorwiseOp::hnormalized() */
156template<typename Derived>
157inline const typename MatrixBase<Derived>::HNormalizedReturnType
158MatrixBase<Derived>::hnormalized() const
159{
160  EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
161  return ConstStartMinusOne(derived(),0,0,
162    ColsAtCompileTime==1?size()-1:1,
163    ColsAtCompileTime==1?1:size()-1) / coeff(size()-1);
164}
165
166/** \geometry_module
167  *
168  * \returns an expression of the homogeneous normalized vector of \c *this
169  *
170  * Example: \include DirectionWise_hnormalized.cpp
171  * Output: \verbinclude DirectionWise_hnormalized.out
172  *
173  * \sa MatrixBase::hnormalized() */
174template<typename ExpressionType, int Direction>
175inline const typename VectorwiseOp<ExpressionType,Direction>::HNormalizedReturnType
176VectorwiseOp<ExpressionType,Direction>::hnormalized() const
177{
178  return HNormalized_Block(_expression(),0,0,
179      Direction==Vertical   ? _expression().rows()-1 : _expression().rows(),
180      Direction==Horizontal ? _expression().cols()-1 : _expression().cols()).cwiseQuotient(
181      Replicate<HNormalized_Factors,
182                Direction==Vertical   ? HNormalized_SizeMinusOne : 1,
183                Direction==Horizontal ? HNormalized_SizeMinusOne : 1>
184        (HNormalized_Factors(_expression(),
185          Direction==Vertical    ? _expression().rows()-1:0,
186          Direction==Horizontal  ? _expression().cols()-1:0,
187          Direction==Vertical    ? 1 : _expression().rows(),
188          Direction==Horizontal  ? 1 : _expression().cols()),
189         Direction==Vertical   ? _expression().rows()-1 : 1,
190         Direction==Horizontal ? _expression().cols()-1 : 1));
191}
192
193namespace internal {
194
195template<typename MatrixOrTransformType>
196struct take_matrix_for_product
197{
198  typedef MatrixOrTransformType type;
199  static const type& run(const type &x) { return x; }
200};
201
202template<typename Scalar, int Dim, int Mode,int Options>
203struct take_matrix_for_product<Transform<Scalar, Dim, Mode, Options> >
204{
205  typedef Transform<Scalar, Dim, Mode, Options> TransformType;
206  typedef typename internal::add_const<typename TransformType::ConstAffinePart>::type type;
207  static type run (const TransformType& x) { return x.affine(); }
208};
209
210template<typename Scalar, int Dim, int Options>
211struct take_matrix_for_product<Transform<Scalar, Dim, Projective, Options> >
212{
213  typedef Transform<Scalar, Dim, Projective, Options> TransformType;
214  typedef typename TransformType::MatrixType type;
215  static const type& run (const TransformType& x) { return x.matrix(); }
216};
217
218template<typename MatrixType,typename Lhs>
219struct traits<homogeneous_left_product_impl<Homogeneous<MatrixType,Vertical>,Lhs> >
220{
221  typedef typename take_matrix_for_product<Lhs>::type LhsMatrixType;
222  typedef typename remove_all<MatrixType>::type MatrixTypeCleaned;
223  typedef typename remove_all<LhsMatrixType>::type LhsMatrixTypeCleaned;
224  typedef typename make_proper_matrix_type<
225                 typename traits<MatrixTypeCleaned>::Scalar,
226                 LhsMatrixTypeCleaned::RowsAtCompileTime,
227                 MatrixTypeCleaned::ColsAtCompileTime,
228                 MatrixTypeCleaned::PlainObject::Options,
229                 LhsMatrixTypeCleaned::MaxRowsAtCompileTime,
230                 MatrixTypeCleaned::MaxColsAtCompileTime>::type ReturnType;
231};
232
233template<typename MatrixType,typename Lhs>
234struct homogeneous_left_product_impl<Homogeneous<MatrixType,Vertical>,Lhs>
235  : public ReturnByValue<homogeneous_left_product_impl<Homogeneous<MatrixType,Vertical>,Lhs> >
236{
237  typedef typename traits<homogeneous_left_product_impl>::LhsMatrixType LhsMatrixType;
238  typedef typename remove_all<LhsMatrixType>::type LhsMatrixTypeCleaned;
239  typedef typename remove_all<typename LhsMatrixTypeCleaned::Nested>::type LhsMatrixTypeNested;
240  typedef typename MatrixType::Index Index;
241  homogeneous_left_product_impl(const Lhs& lhs, const MatrixType& rhs)
242    : m_lhs(take_matrix_for_product<Lhs>::run(lhs)),
243      m_rhs(rhs)
244  {}
245
246  inline Index rows() const { return m_lhs.rows(); }
247  inline Index cols() const { return m_rhs.cols(); }
248
249  template<typename Dest> void evalTo(Dest& dst) const
250  {
251    // FIXME investigate how to allow lazy evaluation of this product when possible
252    dst = Block<const LhsMatrixTypeNested,
253              LhsMatrixTypeNested::RowsAtCompileTime,
254              LhsMatrixTypeNested::ColsAtCompileTime==Dynamic?Dynamic:LhsMatrixTypeNested::ColsAtCompileTime-1>
255            (m_lhs,0,0,m_lhs.rows(),m_lhs.cols()-1) * m_rhs;
256    dst += m_lhs.col(m_lhs.cols()-1).rowwise()
257            .template replicate<MatrixType::ColsAtCompileTime>(m_rhs.cols());
258  }
259
260  typename LhsMatrixTypeCleaned::Nested m_lhs;
261  typename MatrixType::Nested m_rhs;
262};
263
264template<typename MatrixType,typename Rhs>
265struct traits<homogeneous_right_product_impl<Homogeneous<MatrixType,Horizontal>,Rhs> >
266{
267  typedef typename make_proper_matrix_type<typename traits<MatrixType>::Scalar,
268                 MatrixType::RowsAtCompileTime,
269                 Rhs::ColsAtCompileTime,
270                 MatrixType::PlainObject::Options,
271                 MatrixType::MaxRowsAtCompileTime,
272                 Rhs::MaxColsAtCompileTime>::type ReturnType;
273};
274
275template<typename MatrixType,typename Rhs>
276struct homogeneous_right_product_impl<Homogeneous<MatrixType,Horizontal>,Rhs>
277  : public ReturnByValue<homogeneous_right_product_impl<Homogeneous<MatrixType,Horizontal>,Rhs> >
278{
279  typedef typename remove_all<typename Rhs::Nested>::type RhsNested;
280  typedef typename MatrixType::Index Index;
281  homogeneous_right_product_impl(const MatrixType& lhs, const Rhs& rhs)
282    : m_lhs(lhs), m_rhs(rhs)
283  {}
284
285  inline Index rows() const { return m_lhs.rows(); }
286  inline Index cols() const { return m_rhs.cols(); }
287
288  template<typename Dest> void evalTo(Dest& dst) const
289  {
290    // FIXME investigate how to allow lazy evaluation of this product when possible
291    dst = m_lhs * Block<const RhsNested,
292                        RhsNested::RowsAtCompileTime==Dynamic?Dynamic:RhsNested::RowsAtCompileTime-1,
293                        RhsNested::ColsAtCompileTime>
294            (m_rhs,0,0,m_rhs.rows()-1,m_rhs.cols());
295    dst += m_rhs.row(m_rhs.rows()-1).colwise()
296            .template replicate<MatrixType::RowsAtCompileTime>(m_lhs.rows());
297  }
298
299  typename MatrixType::Nested m_lhs;
300  typename Rhs::Nested m_rhs;
301};
302
303} // end namespace internal
304
305} // end namespace Eigen
306
307#endif // EIGEN_HOMOGENEOUS_H
308