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 (at) 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 & HereditaryBits, 47 CoeffReadCost = traits<typename remove_all<ConditionMatrixNested>::type>::CoeffReadCost 48 + EIGEN_SIZE_MAX(traits<typename remove_all<ThenMatrixNested>::type>::CoeffReadCost, 49 traits<typename remove_all<ElseMatrixNested>::type>::CoeffReadCost) 50 }; 51 }; 52 } 53 54 template<typename ConditionMatrixType, typename ThenMatrixType, typename ElseMatrixType> 55 class Select : internal::no_assignment_operator, 56 public internal::dense_xpr_base< Select<ConditionMatrixType, ThenMatrixType, ElseMatrixType> >::type 57 { 58 public: 59 60 typedef typename internal::dense_xpr_base<Select>::type Base; 61 EIGEN_DENSE_PUBLIC_INTERFACE(Select) 62 63 Select(const ConditionMatrixType& a_conditionMatrix, 64 const ThenMatrixType& a_thenMatrix, 65 const ElseMatrixType& a_elseMatrix) 66 : m_condition(a_conditionMatrix), m_then(a_thenMatrix), m_else(a_elseMatrix) 67 { 68 eigen_assert(m_condition.rows() == m_then.rows() && m_condition.rows() == m_else.rows()); 69 eigen_assert(m_condition.cols() == m_then.cols() && m_condition.cols() == m_else.cols()); 70 } 71 72 Index rows() const { return m_condition.rows(); } 73 Index cols() const { return m_condition.cols(); } 74 75 const Scalar coeff(Index i, Index j) const 76 { 77 if (m_condition.coeff(i,j)) 78 return m_then.coeff(i,j); 79 else 80 return m_else.coeff(i,j); 81 } 82 83 const Scalar coeff(Index i) const 84 { 85 if (m_condition.coeff(i)) 86 return m_then.coeff(i); 87 else 88 return m_else.coeff(i); 89 } 90 91 const ConditionMatrixType& conditionMatrix() const 92 { 93 return m_condition; 94 } 95 96 const ThenMatrixType& thenMatrix() const 97 { 98 return m_then; 99 } 100 101 const ElseMatrixType& elseMatrix() const 102 { 103 return m_else; 104 } 105 106 protected: 107 typename ConditionMatrixType::Nested m_condition; 108 typename ThenMatrixType::Nested m_then; 109 typename ElseMatrixType::Nested m_else; 110 }; 111 112 113 /** \returns a matrix where each coefficient (i,j) is equal to \a thenMatrix(i,j) 114 * if \c *this(i,j), and \a elseMatrix(i,j) otherwise. 115 * 116 * Example: \include MatrixBase_select.cpp 117 * Output: \verbinclude MatrixBase_select.out 118 * 119 * \sa class Select 120 */ 121 template<typename Derived> 122 template<typename ThenDerived,typename ElseDerived> 123 inline const Select<Derived,ThenDerived,ElseDerived> 124 DenseBase<Derived>::select(const DenseBase<ThenDerived>& thenMatrix, 125 const DenseBase<ElseDerived>& elseMatrix) const 126 { 127 return Select<Derived,ThenDerived,ElseDerived>(derived(), thenMatrix.derived(), elseMatrix.derived()); 128 } 129 130 /** Version of DenseBase::select(const DenseBase&, const DenseBase&) with 131 * the \em else expression being a scalar value. 132 * 133 * \sa DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select 134 */ 135 template<typename Derived> 136 template<typename ThenDerived> 137 inline const Select<Derived,ThenDerived, typename ThenDerived::ConstantReturnType> 138 DenseBase<Derived>::select(const DenseBase<ThenDerived>& thenMatrix, 139 const typename ThenDerived::Scalar& elseScalar) const 140 { 141 return Select<Derived,ThenDerived,typename ThenDerived::ConstantReturnType>( 142 derived(), thenMatrix.derived(), ThenDerived::Constant(rows(),cols(),elseScalar)); 143 } 144 145 /** Version of DenseBase::select(const DenseBase&, const DenseBase&) with 146 * the \em then expression being a scalar value. 147 * 148 * \sa DenseBase::select(const DenseBase<ThenDerived>&, const DenseBase<ElseDerived>&) const, class Select 149 */ 150 template<typename Derived> 151 template<typename ElseDerived> 152 inline const Select<Derived, typename ElseDerived::ConstantReturnType, ElseDerived > 153 DenseBase<Derived>::select(const typename ElseDerived::Scalar& thenScalar, 154 const DenseBase<ElseDerived>& elseMatrix) const 155 { 156 return Select<Derived,typename ElseDerived::ConstantReturnType,ElseDerived>( 157 derived(), ElseDerived::Constant(rows(),cols(),thenScalar), elseMatrix.derived()); 158 } 159 160 } // end namespace Eigen 161 162 #endif // EIGEN_SELECT_H 163
