[136] | 1 | // This file is part of Eigen, a lightweight C++ template library
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| 2 | // for linear algebra.
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| 3 | //
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| 4 | // Copyright (C) 2006-2009 Benoit Jacob <jacob.benoit.1@gmail.com>
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| 5 | //
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| 6 | // This Source Code Form is subject to the terms of the Mozilla
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| 7 | // Public License v. 2.0. If a copy of the MPL was not distributed
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| 8 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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| 9 |
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| 10 | #ifndef EIGEN_MINOR_H
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| 11 | #define EIGEN_MINOR_H
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| 12 |
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| 13 | namespace Eigen {
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| 14 |
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| 15 | /**
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| 16 | * \class Minor
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| 17 | *
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| 18 | * \brief Expression of a minor
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| 19 | *
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| 20 | * \param MatrixType the type of the object in which we are taking a minor
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| 21 | *
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| 22 | * This class represents an expression of a minor. It is the return
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| 23 | * type of MatrixBase::minor() and most of the time this is the only way it
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| 24 | * is used.
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| 25 | *
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| 26 | * \sa MatrixBase::minor()
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| 27 | */
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| 28 |
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| 29 | namespace internal {
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| 30 | template<typename MatrixType>
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| 31 | struct traits<Minor<MatrixType> >
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| 32 | : traits<MatrixType>
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| 33 | {
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| 34 | typedef typename nested<MatrixType>::type MatrixTypeNested;
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| 35 | typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
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| 36 | typedef typename MatrixType::StorageKind StorageKind;
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| 37 | enum {
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| 38 | RowsAtCompileTime = (MatrixType::RowsAtCompileTime != Dynamic) ?
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| 39 | int(MatrixType::RowsAtCompileTime) - 1 : Dynamic,
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| 40 | ColsAtCompileTime = (MatrixType::ColsAtCompileTime != Dynamic) ?
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| 41 | int(MatrixType::ColsAtCompileTime) - 1 : Dynamic,
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| 42 | MaxRowsAtCompileTime = (MatrixType::MaxRowsAtCompileTime != Dynamic) ?
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| 43 | int(MatrixType::MaxRowsAtCompileTime) - 1 : Dynamic,
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| 44 | MaxColsAtCompileTime = (MatrixType::MaxColsAtCompileTime != Dynamic) ?
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| 45 | int(MatrixType::MaxColsAtCompileTime) - 1 : Dynamic,
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| 46 | Flags = _MatrixTypeNested::Flags & (HereditaryBits | LvalueBit),
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| 47 | CoeffReadCost = _MatrixTypeNested::CoeffReadCost // minor is used typically on tiny matrices,
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| 48 | // where loops are unrolled and the 'if' evaluates at compile time
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| 49 | };
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| 50 | };
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| 51 | }
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| 52 |
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| 53 | template<typename MatrixType> class Minor
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| 54 | : public MatrixBase<Minor<MatrixType> >
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| 55 | {
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| 56 | public:
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| 57 |
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| 58 | typedef MatrixBase<Minor> Base;
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| 59 | EIGEN_DENSE_PUBLIC_INTERFACE(Minor)
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| 60 |
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| 61 | inline Minor(const MatrixType& matrix,
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| 62 | Index row, Index col)
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| 63 | : m_matrix(matrix), m_row(row), m_col(col)
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| 64 | {
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| 65 | eigen_assert(row >= 0 && row < matrix.rows()
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| 66 | && col >= 0 && col < matrix.cols());
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| 67 | }
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| 68 |
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| 69 | EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Minor)
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| 70 |
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| 71 | inline Index rows() const { return m_matrix.rows() - 1; }
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| 72 | inline Index cols() const { return m_matrix.cols() - 1; }
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| 73 |
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| 74 | inline Scalar& coeffRef(Index row, Index col)
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| 75 | {
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| 76 | return m_matrix.const_cast_derived().coeffRef(row + (row >= m_row), col + (col >= m_col));
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| 77 | }
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| 78 |
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| 79 | inline const Scalar coeff(Index row, Index col) const
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| 80 | {
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| 81 | return m_matrix.coeff(row + (row >= m_row), col + (col >= m_col));
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| 82 | }
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| 83 |
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| 84 | protected:
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| 85 | const typename MatrixType::Nested m_matrix;
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| 86 | const Index m_row, m_col;
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| 87 | };
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| 88 |
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| 89 | /**
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| 90 | * \return an expression of the (\a row, \a col)-minor of *this,
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| 91 | * i.e. an expression constructed from *this by removing the specified
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| 92 | * row and column.
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| 93 | *
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| 94 | * Example: \include MatrixBase_minor.cpp
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| 95 | * Output: \verbinclude MatrixBase_minor.out
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| 96 | *
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| 97 | * \sa class Minor
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| 98 | */
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| 99 | template<typename Derived>
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| 100 | inline Minor<Derived>
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| 101 | MatrixBase<Derived>::minor(Index row, Index col)
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| 102 | {
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| 103 | return Minor<Derived>(derived(), row, col);
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| 104 | }
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| 105 |
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| 106 | /**
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| 107 | * This is the const version of minor(). */
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| 108 | template<typename Derived>
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| 109 | inline const Minor<Derived>
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| 110 | MatrixBase<Derived>::minor(Index row, Index col) const
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| 111 | {
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| 112 | return Minor<Derived>(derived(), row, col);
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| 113 | }
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| 114 |
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| 115 | } // end namespace Eigen
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| 116 |
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| 117 | #endif // EIGEN_MINOR_H
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