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) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr> |
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5 | // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com> |
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6 | // |
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7 | // This Source Code Form is subject to the terms of the Mozilla |
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8 | // Public License v. 2.0. If a copy of the MPL was not distributed |
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9 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. |
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10 | |
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11 | #ifndef EIGEN_META_H |
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12 | #define EIGEN_META_H |
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13 | |
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14 | namespace Eigen { |
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15 | |
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16 | namespace internal { |
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17 | |
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18 | /** \internal |
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19 | * \file Meta.h |
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20 | * This file contains generic metaprogramming classes which are not specifically related to Eigen. |
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21 | * \note In case you wonder, yes we're aware that Boost already provides all these features, |
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22 | * we however don't want to add a dependency to Boost. |
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23 | */ |
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24 | |
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25 | struct true_type { enum { value = 1 }; }; |
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26 | struct false_type { enum { value = 0 }; }; |
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27 | |
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28 | template<bool Condition, typename Then, typename Else> |
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29 | struct conditional { typedef Then type; }; |
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30 | |
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31 | template<typename Then, typename Else> |
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32 | struct conditional <false, Then, Else> { typedef Else type; }; |
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33 | |
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34 | template<typename T, typename U> struct is_same { enum { value = 0 }; }; |
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35 | template<typename T> struct is_same<T,T> { enum { value = 1 }; }; |
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36 | |
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37 | template<typename T> struct remove_reference { typedef T type; }; |
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38 | template<typename T> struct remove_reference<T&> { typedef T type; }; |
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39 | |
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40 | template<typename T> struct remove_pointer { typedef T type; }; |
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41 | template<typename T> struct remove_pointer<T*> { typedef T type; }; |
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42 | template<typename T> struct remove_pointer<T*const> { typedef T type; }; |
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43 | |
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44 | template <class T> struct remove_const { typedef T type; }; |
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45 | template <class T> struct remove_const<const T> { typedef T type; }; |
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46 | template <class T> struct remove_const<const T[]> { typedef T type[]; }; |
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47 | template <class T, unsigned int Size> struct remove_const<const T[Size]> { typedef T type[Size]; }; |
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48 | |
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49 | template<typename T> struct remove_all { typedef T type; }; |
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50 | template<typename T> struct remove_all<const T> { typedef typename remove_all<T>::type type; }; |
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51 | template<typename T> struct remove_all<T const&> { typedef typename remove_all<T>::type type; }; |
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52 | template<typename T> struct remove_all<T&> { typedef typename remove_all<T>::type type; }; |
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53 | template<typename T> struct remove_all<T const*> { typedef typename remove_all<T>::type type; }; |
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54 | template<typename T> struct remove_all<T*> { typedef typename remove_all<T>::type type; }; |
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55 | |
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56 | template<typename T> struct is_arithmetic { enum { value = false }; }; |
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57 | template<> struct is_arithmetic<float> { enum { value = true }; }; |
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58 | template<> struct is_arithmetic<double> { enum { value = true }; }; |
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59 | template<> struct is_arithmetic<long double> { enum { value = true }; }; |
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60 | template<> struct is_arithmetic<bool> { enum { value = true }; }; |
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61 | template<> struct is_arithmetic<char> { enum { value = true }; }; |
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62 | template<> struct is_arithmetic<signed char> { enum { value = true }; }; |
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63 | template<> struct is_arithmetic<unsigned char> { enum { value = true }; }; |
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64 | template<> struct is_arithmetic<signed short> { enum { value = true }; }; |
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65 | template<> struct is_arithmetic<unsigned short>{ enum { value = true }; }; |
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66 | template<> struct is_arithmetic<signed int> { enum { value = true }; }; |
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67 | template<> struct is_arithmetic<unsigned int> { enum { value = true }; }; |
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68 | template<> struct is_arithmetic<signed long> { enum { value = true }; }; |
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69 | template<> struct is_arithmetic<unsigned long> { enum { value = true }; }; |
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70 | |
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71 | template <typename T> struct add_const { typedef const T type; }; |
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72 | template <typename T> struct add_const<T&> { typedef T& type; }; |
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73 | |
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74 | template <typename T> struct is_const { enum { value = 0 }; }; |
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75 | template <typename T> struct is_const<T const> { enum { value = 1 }; }; |
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76 | |
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77 | template<typename T> struct add_const_on_value_type { typedef const T type; }; |
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78 | template<typename T> struct add_const_on_value_type<T&> { typedef T const& type; }; |
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79 | template<typename T> struct add_const_on_value_type<T*> { typedef T const* type; }; |
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80 | template<typename T> struct add_const_on_value_type<T* const> { typedef T const* const type; }; |
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81 | template<typename T> struct add_const_on_value_type<T const* const> { typedef T const* const type; }; |
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82 | |
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83 | /** \internal Allows to enable/disable an overload |
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84 | * according to a compile time condition. |
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85 | */ |
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86 | template<bool Condition, typename T> struct enable_if; |
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87 | |
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88 | template<typename T> struct enable_if<true,T> |
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89 | { typedef T type; }; |
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90 | |
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91 | |
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92 | |
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93 | /** \internal |
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94 | * A base class do disable default copy ctor and copy assignement operator. |
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95 | */ |
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96 | class noncopyable |
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97 | { |
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98 | noncopyable(const noncopyable&); |
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99 | const noncopyable& operator=(const noncopyable&); |
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100 | protected: |
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101 | noncopyable() {} |
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102 | ~noncopyable() {} |
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103 | }; |
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104 | |
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105 | |
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106 | /** \internal |
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107 | * Convenient struct to get the result type of a unary or binary functor. |
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108 | * |
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109 | * It supports both the current STL mechanism (using the result_type member) as well as |
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110 | * upcoming next STL generation (using a templated result member). |
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111 | * If none of these members is provided, then the type of the first argument is returned. FIXME, that behavior is a pretty bad hack. |
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112 | */ |
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113 | template<typename T> struct result_of {}; |
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114 | |
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115 | struct has_none {int a[1];}; |
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116 | struct has_std_result_type {int a[2];}; |
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117 | struct has_tr1_result {int a[3];}; |
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118 | |
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119 | template<typename Func, typename ArgType, int SizeOf=sizeof(has_none)> |
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120 | struct unary_result_of_select {typedef ArgType type;}; |
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121 | |
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122 | template<typename Func, typename ArgType> |
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123 | struct unary_result_of_select<Func, ArgType, sizeof(has_std_result_type)> {typedef typename Func::result_type type;}; |
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124 | |
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125 | template<typename Func, typename ArgType> |
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126 | struct unary_result_of_select<Func, ArgType, sizeof(has_tr1_result)> {typedef typename Func::template result<Func(ArgType)>::type type;}; |
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127 | |
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128 | template<typename Func, typename ArgType> |
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129 | struct result_of<Func(ArgType)> { |
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130 | template<typename T> |
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131 | static has_std_result_type testFunctor(T const *, typename T::result_type const * = 0); |
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132 | template<typename T> |
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133 | static has_tr1_result testFunctor(T const *, typename T::template result<T(ArgType)>::type const * = 0); |
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134 | static has_none testFunctor(...); |
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135 | |
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136 | // note that the following indirection is needed for gcc-3.3 |
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137 | enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))}; |
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138 | typedef typename unary_result_of_select<Func, ArgType, FunctorType>::type type; |
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139 | }; |
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140 | |
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141 | template<typename Func, typename ArgType0, typename ArgType1, int SizeOf=sizeof(has_none)> |
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142 | struct binary_result_of_select {typedef ArgType0 type;}; |
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143 | |
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144 | template<typename Func, typename ArgType0, typename ArgType1> |
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145 | struct binary_result_of_select<Func, ArgType0, ArgType1, sizeof(has_std_result_type)> |
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146 | {typedef typename Func::result_type type;}; |
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147 | |
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148 | template<typename Func, typename ArgType0, typename ArgType1> |
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149 | struct binary_result_of_select<Func, ArgType0, ArgType1, sizeof(has_tr1_result)> |
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150 | {typedef typename Func::template result<Func(ArgType0,ArgType1)>::type type;}; |
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151 | |
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152 | template<typename Func, typename ArgType0, typename ArgType1> |
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153 | struct result_of<Func(ArgType0,ArgType1)> { |
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154 | template<typename T> |
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155 | static has_std_result_type testFunctor(T const *, typename T::result_type const * = 0); |
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156 | template<typename T> |
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157 | static has_tr1_result testFunctor(T const *, typename T::template result<T(ArgType0,ArgType1)>::type const * = 0); |
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158 | static has_none testFunctor(...); |
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159 | |
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160 | // note that the following indirection is needed for gcc-3.3 |
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161 | enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))}; |
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162 | typedef typename binary_result_of_select<Func, ArgType0, ArgType1, FunctorType>::type type; |
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163 | }; |
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164 | |
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165 | /** \internal In short, it computes int(sqrt(\a Y)) with \a Y an integer. |
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166 | * Usage example: \code meta_sqrt<1023>::ret \endcode |
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167 | */ |
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168 | template<int Y, |
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169 | int InfX = 0, |
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170 | int SupX = ((Y==1) ? 1 : Y/2), |
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171 | bool Done = ((SupX-InfX)<=1 ? true : ((SupX*SupX <= Y) && ((SupX+1)*(SupX+1) > Y))) > |
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172 | // use ?: instead of || just to shut up a stupid gcc 4.3 warning |
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173 | class meta_sqrt |
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174 | { |
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175 | enum { |
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176 | MidX = (InfX+SupX)/2, |
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177 | TakeInf = MidX*MidX > Y ? 1 : 0, |
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178 | NewInf = int(TakeInf) ? InfX : int(MidX), |
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179 | NewSup = int(TakeInf) ? int(MidX) : SupX |
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180 | }; |
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181 | public: |
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182 | enum { ret = meta_sqrt<Y,NewInf,NewSup>::ret }; |
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183 | }; |
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184 | |
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185 | template<int Y, int InfX, int SupX> |
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186 | class meta_sqrt<Y, InfX, SupX, true> { public: enum { ret = (SupX*SupX <= Y) ? SupX : InfX }; }; |
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187 | |
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188 | /** \internal determines whether the product of two numeric types is allowed and what the return type is */ |
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189 | template<typename T, typename U> struct scalar_product_traits; |
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190 | |
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191 | template<typename T> struct scalar_product_traits<T,T> |
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192 | { |
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193 | //enum { Cost = NumTraits<T>::MulCost }; |
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194 | typedef T ReturnType; |
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195 | }; |
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196 | |
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197 | template<typename T> struct scalar_product_traits<T,std::complex<T> > |
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198 | { |
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199 | //enum { Cost = 2*NumTraits<T>::MulCost }; |
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200 | typedef std::complex<T> ReturnType; |
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201 | }; |
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202 | |
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203 | template<typename T> struct scalar_product_traits<std::complex<T>, T> |
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204 | { |
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205 | //enum { Cost = 2*NumTraits<T>::MulCost }; |
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206 | typedef std::complex<T> ReturnType; |
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207 | }; |
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208 | |
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209 | // FIXME quick workaround around current limitation of result_of |
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210 | // template<typename Scalar, typename ArgType0, typename ArgType1> |
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211 | // struct result_of<scalar_product_op<Scalar>(ArgType0,ArgType1)> { |
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212 | // typedef typename scalar_product_traits<typename remove_all<ArgType0>::type, typename remove_all<ArgType1>::type>::ReturnType type; |
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213 | // }; |
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214 | |
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215 | template<typename T> struct is_diagonal |
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216 | { enum { ret = false }; }; |
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217 | |
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218 | template<typename T> struct is_diagonal<DiagonalBase<T> > |
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219 | { enum { ret = true }; }; |
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220 | |
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221 | template<typename T> struct is_diagonal<DiagonalWrapper<T> > |
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222 | { enum { ret = true }; }; |
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223 | |
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224 | template<typename T, int S> struct is_diagonal<DiagonalMatrix<T,S> > |
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225 | { enum { ret = true }; }; |
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226 | |
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227 | } // end namespace internal |
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228 | |
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229 | } // end namespace Eigen |
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230 | |
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231 | #endif // EIGEN_META_H |
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