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