Select.h (6143B)
1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2008-2010 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_SELECT_H 11 #define EIGEN_SELECT_H 12 13 namespace Eigen { 14 15 /** \class Select 16 * \ingroup Core_Module 17 * 18 * \brief Expression of a coefficient wise version of the C++ ternary operator ?: 19 * 20 * \param ConditionMatrixType the type of the \em condition expression which must be a boolean matrix 21 * \param ThenMatrixType the type of the \em then expression 22 * \param ElseMatrixType the type of the \em else expression 23 * 24 * This class represents an expression of a coefficient wise version of the C++ ternary operator ?:. 25 * It is the return type of DenseBase::select() and most of the time this is the only way it is used. 26 * 27 * \sa DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const 28 */ 29 30 namespace internal { 31 template<typename ConditionMatrixType, typename ThenMatrixType, typename ElseMatrixType> 32 struct traits<Select<ConditionMatrixType, ThenMatrixType, ElseMatrixType> > 33 : traits<ThenMatrixType> 34 { 35 typedef typename traits<ThenMatrixType>::Scalar Scalar; 36 typedef Dense StorageKind; 37 typedef typename traits<ThenMatrixType>::XprKind XprKind; 38 typedef typename ConditionMatrixType::Nested ConditionMatrixNested; 39 typedef typename ThenMatrixType::Nested ThenMatrixNested; 40 typedef typename ElseMatrixType::Nested ElseMatrixNested; 41 enum { 42 RowsAtCompileTime = ConditionMatrixType::RowsAtCompileTime, 43 ColsAtCompileTime = ConditionMatrixType::ColsAtCompileTime, 44 MaxRowsAtCompileTime = ConditionMatrixType::MaxRowsAtCompileTime, 45 MaxColsAtCompileTime = ConditionMatrixType::MaxColsAtCompileTime, 46 Flags = (unsigned int)ThenMatrixType::Flags & ElseMatrixType::Flags & RowMajorBit 47 }; 48 }; 49 } 50 51 template<typename ConditionMatrixType, typename ThenMatrixType, typename ElseMatrixType> 52 class Select : public internal::dense_xpr_base< Select<ConditionMatrixType, ThenMatrixType, ElseMatrixType> >::type, 53 internal::no_assignment_operator 54 { 55 public: 56 57 typedef typename internal::dense_xpr_base<Select>::type Base; 58 EIGEN_DENSE_PUBLIC_INTERFACE(Select) 59 60 inline EIGEN_DEVICE_FUNC 61 Select(const ConditionMatrixType& a_conditionMatrix, 62 const ThenMatrixType& a_thenMatrix, 63 const ElseMatrixType& a_elseMatrix) 64 : m_condition(a_conditionMatrix), m_then(a_thenMatrix), m_else(a_elseMatrix) 65 { 66 eigen_assert(m_condition.rows() == m_then.rows() && m_condition.rows() == m_else.rows()); 67 eigen_assert(m_condition.cols() == m_then.cols() && m_condition.cols() == m_else.cols()); 68 } 69 70 inline EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR 71 Index rows() const EIGEN_NOEXCEPT { return m_condition.rows(); } 72 inline EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR 73 Index cols() const EIGEN_NOEXCEPT { return m_condition.cols(); } 74 75 inline EIGEN_DEVICE_FUNC 76 const Scalar coeff(Index i, Index j) const 77 { 78 if (m_condition.coeff(i,j)) 79 return m_then.coeff(i,j); 80 else 81 return m_else.coeff(i,j); 82 } 83 84 inline EIGEN_DEVICE_FUNC 85 const Scalar coeff(Index i) const 86 { 87 if (m_condition.coeff(i)) 88 return m_then.coeff(i); 89 else 90 return m_else.coeff(i); 91 } 92 93 inline EIGEN_DEVICE_FUNC const ConditionMatrixType& conditionMatrix() const 94 { 95 return m_condition; 96 } 97 98 inline EIGEN_DEVICE_FUNC const ThenMatrixType& thenMatrix() const 99 { 100 return m_then; 101 } 102 103 inline EIGEN_DEVICE_FUNC const ElseMatrixType& elseMatrix() const 104 { 105 return m_else; 106 } 107 108 protected: 109 typename ConditionMatrixType::Nested m_condition; 110 typename ThenMatrixType::Nested m_then; 111 typename ElseMatrixType::Nested m_else; 112 }; 113 114 115 /** \returns a matrix where each coefficient (i,j) is equal to \a thenMatrix(i,j) 116 * if \c *this(i,j), and \a elseMatrix(i,j) otherwise. 117 * 118 * Example: \include MatrixBase_select.cpp 119 * Output: \verbinclude MatrixBase_select.out 120 * 121 * \sa class Select 122 */ 123 template<typename Derived> 124 template<typename ThenDerived,typename ElseDerived> 125 inline EIGEN_DEVICE_FUNC const Select<Derived,ThenDerived,ElseDerived> 126 DenseBase<Derived>::select(const DenseBase<ThenDerived>& thenMatrix, 127 const DenseBase<ElseDerived>& elseMatrix) const 128 { 129 return Select<Derived,ThenDerived,ElseDerived>(derived(), thenMatrix.derived(), elseMatrix.derived()); 130 } 131 132 /** Version of DenseBase::select(const DenseBase&, const DenseBase&) with 133 * the \em else expression being a scalar value. 134 * 135 * \sa DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select 136 */ 137 template<typename Derived> 138 template<typename ThenDerived> 139 inline EIGEN_DEVICE_FUNC const Select<Derived,ThenDerived, typename ThenDerived::ConstantReturnType> 140 DenseBase<Derived>::select(const DenseBase<ThenDerived>& thenMatrix, 141 const typename ThenDerived::Scalar& elseScalar) const 142 { 143 return Select<Derived,ThenDerived,typename ThenDerived::ConstantReturnType>( 144 derived(), thenMatrix.derived(), ThenDerived::Constant(rows(),cols(),elseScalar)); 145 } 146 147 /** Version of DenseBase::select(const DenseBase&, const DenseBase&) with 148 * the \em then expression being a scalar value. 149 * 150 * \sa DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select 151 */ 152 template<typename Derived> 153 template<typename ElseDerived> 154 inline EIGEN_DEVICE_FUNC const Select<Derived, typename ElseDerived::ConstantReturnType, ElseDerived > 155 DenseBase<Derived>::select(const typename ElseDerived::Scalar& thenScalar, 156 const DenseBase<ElseDerived>& elseMatrix) const 157 { 158 return Select<Derived,typename ElseDerived::ConstantReturnType,ElseDerived>( 159 derived(), ElseDerived::Constant(rows(),cols(),thenScalar), elseMatrix.derived()); 160 } 161 162 } // end namespace Eigen 163 164 #endif // EIGEN_SELECT_H