1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
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_MISC_IMAGE_H
11 #define EIGEN_MISC_IMAGE_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 /** \class image_retval_base
18   *
19   */
20 template<typename DecompositionType>
21 struct traits<image_retval_base<DecompositionType> >
22 {
23   typedef typename DecompositionType::MatrixType MatrixType;
24   typedef Matrix<
25     typename MatrixType::Scalar,
26     MatrixType::RowsAtCompileTime, // the image is a subspace of the destination space, whose
27                                    // dimension is the number of rows of the original matrix
28     Dynamic,                       // we don't know at compile time the dimension of the image (the rank)
29     MatrixType::Options,
30     MatrixType::MaxRowsAtCompileTime, // the image matrix will consist of columns from the original matrix,
31     MatrixType::MaxColsAtCompileTime  // so it has the same number of rows and at most as many columns.
32   > ReturnType;
33 };
34 
35 template<typename _DecompositionType> struct image_retval_base
36  : public ReturnByValue<image_retval_base<_DecompositionType> >
37 {
38   typedef _DecompositionType DecompositionType;
39   typedef typename DecompositionType::MatrixType MatrixType;
40   typedef ReturnByValue<image_retval_base> Base;
41 
42   image_retval_base(const DecompositionType& dec, const MatrixType& originalMatrix)
43     : m_dec(dec), m_rank(dec.rank()),
44       m_cols(m_rank == 0 ? 1 : m_rank),
45       m_originalMatrix(originalMatrix)
46   {}
47 
48   inline Index rows() const { return m_dec.rows(); }
49   inline Index cols() const { return m_cols; }
50   inline Index rank() const { return m_rank; }
51   inline const DecompositionType& dec() const { return m_dec; }
52   inline const MatrixType& originalMatrix() const { return m_originalMatrix; }
53 
54   template<typename Dest> inline void evalTo(Dest& dst) const
55   {
56     static_cast<const image_retval<DecompositionType>*>(this)->evalTo(dst);
57   }
58 
59   protected:
60     const DecompositionType& m_dec;
61     Index m_rank, m_cols;
62     const MatrixType& m_originalMatrix;
63 };
64 
65 } // end namespace internal
66 
67 #define EIGEN_MAKE_IMAGE_HELPERS(DecompositionType) \
68   typedef typename DecompositionType::MatrixType MatrixType; \
69   typedef typename MatrixType::Scalar Scalar; \
70   typedef typename MatrixType::RealScalar RealScalar; \
71   typedef Eigen::internal::image_retval_base<DecompositionType> Base; \
72   using Base::dec; \
73   using Base::originalMatrix; \
74   using Base::rank; \
75   using Base::rows; \
76   using Base::cols; \
77   image_retval(const DecompositionType& dec, const MatrixType& originalMatrix) \
78     : Base(dec, originalMatrix) {}
79 
80 } // end namespace Eigen
81 
82 #endif // EIGEN_MISC_IMAGE_H
83