1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>
5 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
6 //
7 // This Source Code Form is subject to the terms of the Mozilla
8 // Public License v. 2.0. If a copy of the MPL was not distributed
9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
10
11 #ifndef EIGEN_BLOCK2_H
12 #define EIGEN_BLOCK2_H
13
14 namespace Eigen {
15
16 /** \returns a dynamic-size expression of a corner of *this.
17 *
18 * \param type the type of corner. Can be \a Eigen::TopLeft, \a Eigen::TopRight,
19 * \a Eigen::BottomLeft, \a Eigen::BottomRight.
20 * \param cRows the number of rows in the corner
21 * \param cCols the number of columns in the corner
22 *
23 * Example: \include MatrixBase_corner_enum_int_int.cpp
24 * Output: \verbinclude MatrixBase_corner_enum_int_int.out
25 *
26 * \note Even though the returned expression has dynamic size, in the case
27 * when it is applied to a fixed-size matrix, it inherits a fixed maximal size,
28 * which means that evaluating it does not cause a dynamic memory allocation.
29 *
30 * \sa class Block, block(Index,Index,Index,Index)
31 */
32 template<typename Derived>
33 inline Block<Derived> DenseBase<Derived>
corner(CornerType type,Index cRows,Index cCols)34 ::corner(CornerType type, Index cRows, Index cCols)
35 {
36 switch(type)
37 {
38 default:
39 eigen_assert(false && "Bad corner type.");
40 case TopLeft:
41 return Block<Derived>(derived(), 0, 0, cRows, cCols);
42 case TopRight:
43 return Block<Derived>(derived(), 0, cols() - cCols, cRows, cCols);
44 case BottomLeft:
45 return Block<Derived>(derived(), rows() - cRows, 0, cRows, cCols);
46 case BottomRight:
47 return Block<Derived>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
48 }
49 }
50
51 /** This is the const version of corner(CornerType, Index, Index).*/
52 template<typename Derived>
53 inline const Block<Derived>
corner(CornerType type,Index cRows,Index cCols)54 DenseBase<Derived>::corner(CornerType type, Index cRows, Index cCols) const
55 {
56 switch(type)
57 {
58 default:
59 eigen_assert(false && "Bad corner type.");
60 case TopLeft:
61 return Block<Derived>(derived(), 0, 0, cRows, cCols);
62 case TopRight:
63 return Block<Derived>(derived(), 0, cols() - cCols, cRows, cCols);
64 case BottomLeft:
65 return Block<Derived>(derived(), rows() - cRows, 0, cRows, cCols);
66 case BottomRight:
67 return Block<Derived>(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
68 }
69 }
70
71 /** \returns a fixed-size expression of a corner of *this.
72 *
73 * \param type the type of corner. Can be \a Eigen::TopLeft, \a Eigen::TopRight,
74 * \a Eigen::BottomLeft, \a Eigen::BottomRight.
75 *
76 * The template parameters CRows and CCols arethe number of rows and columns in the corner.
77 *
78 * Example: \include MatrixBase_template_int_int_corner_enum.cpp
79 * Output: \verbinclude MatrixBase_template_int_int_corner_enum.out
80 *
81 * \sa class Block, block(Index,Index,Index,Index)
82 */
83 template<typename Derived>
84 template<int CRows, int CCols>
85 inline Block<Derived, CRows, CCols>
corner(CornerType type)86 DenseBase<Derived>::corner(CornerType type)
87 {
88 switch(type)
89 {
90 default:
91 eigen_assert(false && "Bad corner type.");
92 case TopLeft:
93 return Block<Derived, CRows, CCols>(derived(), 0, 0);
94 case TopRight:
95 return Block<Derived, CRows, CCols>(derived(), 0, cols() - CCols);
96 case BottomLeft:
97 return Block<Derived, CRows, CCols>(derived(), rows() - CRows, 0);
98 case BottomRight:
99 return Block<Derived, CRows, CCols>(derived(), rows() - CRows, cols() - CCols);
100 }
101 }
102
103 /** This is the const version of corner<int, int>(CornerType).*/
104 template<typename Derived>
105 template<int CRows, int CCols>
106 inline const Block<Derived, CRows, CCols>
corner(CornerType type)107 DenseBase<Derived>::corner(CornerType type) const
108 {
109 switch(type)
110 {
111 default:
112 eigen_assert(false && "Bad corner type.");
113 case TopLeft:
114 return Block<Derived, CRows, CCols>(derived(), 0, 0);
115 case TopRight:
116 return Block<Derived, CRows, CCols>(derived(), 0, cols() - CCols);
117 case BottomLeft:
118 return Block<Derived, CRows, CCols>(derived(), rows() - CRows, 0);
119 case BottomRight:
120 return Block<Derived, CRows, CCols>(derived(), rows() - CRows, cols() - CCols);
121 }
122 }
123
124 } // end namespace Eigen
125
126 #endif // EIGEN_BLOCK2_H
127