1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2006-2009 Benoit Jacob <jacob.benoit.1 (at) 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_MINOR_H 11 #define EIGEN_MINOR_H 12 13 namespace Eigen { 14 15 /** 16 * \class Minor 17 * 18 * \brief Expression of a minor 19 * 20 * \param MatrixType the type of the object in which we are taking a minor 21 * 22 * This class represents an expression of a minor. It is the return 23 * type of MatrixBase::minor() and most of the time this is the only way it 24 * is used. 25 * 26 * \sa MatrixBase::minor() 27 */ 28 29 namespace internal { 30 template<typename MatrixType> 31 struct traits<Minor<MatrixType> > 32 : traits<MatrixType> 33 { 34 typedef typename nested<MatrixType>::type MatrixTypeNested; 35 typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested; 36 typedef typename MatrixType::StorageKind StorageKind; 37 enum { 38 RowsAtCompileTime = (MatrixType::RowsAtCompileTime != Dynamic) ? 39 int(MatrixType::RowsAtCompileTime) - 1 : Dynamic, 40 ColsAtCompileTime = (MatrixType::ColsAtCompileTime != Dynamic) ? 41 int(MatrixType::ColsAtCompileTime) - 1 : Dynamic, 42 MaxRowsAtCompileTime = (MatrixType::MaxRowsAtCompileTime != Dynamic) ? 43 int(MatrixType::MaxRowsAtCompileTime) - 1 : Dynamic, 44 MaxColsAtCompileTime = (MatrixType::MaxColsAtCompileTime != Dynamic) ? 45 int(MatrixType::MaxColsAtCompileTime) - 1 : Dynamic, 46 Flags = _MatrixTypeNested::Flags & (HereditaryBits | LvalueBit), 47 CoeffReadCost = _MatrixTypeNested::CoeffReadCost // minor is used typically on tiny matrices, 48 // where loops are unrolled and the 'if' evaluates at compile time 49 }; 50 }; 51 } 52 53 template<typename MatrixType> class Minor 54 : public MatrixBase<Minor<MatrixType> > 55 { 56 public: 57 58 typedef MatrixBase<Minor> Base; 59 EIGEN_DENSE_PUBLIC_INTERFACE(Minor) 60 61 inline Minor(const MatrixType& matrix, 62 Index row, Index col) 63 : m_matrix(matrix), m_row(row), m_col(col) 64 { 65 eigen_assert(row >= 0 && row < matrix.rows() 66 && col >= 0 && col < matrix.cols()); 67 } 68 69 EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Minor) 70 71 inline Index rows() const { return m_matrix.rows() - 1; } 72 inline Index cols() const { return m_matrix.cols() - 1; } 73 74 inline Scalar& coeffRef(Index row, Index col) 75 { 76 return m_matrix.const_cast_derived().coeffRef(row + (row >= m_row), col + (col >= m_col)); 77 } 78 79 inline const Scalar coeff(Index row, Index col) const 80 { 81 return m_matrix.coeff(row + (row >= m_row), col + (col >= m_col)); 82 } 83 84 protected: 85 const typename MatrixType::Nested m_matrix; 86 const Index m_row, m_col; 87 }; 88 89 /** 90 * \return an expression of the (\a row, \a col)-minor of *this, 91 * i.e. an expression constructed from *this by removing the specified 92 * row and column. 93 * 94 * Example: \include MatrixBase_minor.cpp 95 * Output: \verbinclude MatrixBase_minor.out 96 * 97 * \sa class Minor 98 */ 99 template<typename Derived> 100 inline Minor<Derived> 101 MatrixBase<Derived>::minor(Index row, Index col) 102 { 103 return Minor<Derived>(derived(), row, col); 104 } 105 106 /** 107 * This is the const version of minor(). */ 108 template<typename Derived> 109 inline const Minor<Derived> 110 MatrixBase<Derived>::minor(Index row, Index col) const 111 { 112 return Minor<Derived>(derived(), row, col); 113 } 114 115 } // end namespace Eigen 116 117 #endif // EIGEN_MINOR_H 118
