1 | /*************************************************************************** |
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2 | * blitz/array/storage.h Memory layout of Arrays. |
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3 | * |
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4 | * Copyright (C) 1997-2001 Todd Veldhuizen <tveldhui@oonumerics.org> |
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5 | * |
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6 | * This program is free software; you can redistribute it and/or |
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7 | * modify it under the terms of the GNU General Public License |
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8 | * as published by the Free Software Foundation; either version 2 |
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9 | * of the License, or (at your option) any later version. |
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10 | * |
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11 | * This program is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU General Public License for more details. |
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15 | * |
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16 | * Suggestions: blitz-dev@oonumerics.org |
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17 | * Bugs: blitz-bugs@oonumerics.org |
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18 | * |
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19 | * For more information, please see the Blitz++ Home Page: |
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20 | * http://oonumerics.org/blitz/ |
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21 | * |
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22 | ****************************************************************************/ |
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23 | #ifndef BZ_ARRAY_STORAGE_H |
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24 | #define BZ_ARRAY_STORAGE_H |
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25 | |
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26 | BZ_NAMESPACE(blitz) |
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27 | |
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28 | /* |
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29 | * Declaration of class GeneralStorage<N_rank> |
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30 | * |
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31 | * This class describes a storage format for an N-dimensional array. |
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32 | * The dimensions can be stored in an arbitrary order (for example, as |
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33 | * a C-style row major array or Fortran-style column major array, or |
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34 | * something else entirely). Each dimension can be stored in either |
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35 | * ascending (the most common) or descending order. Each dimension |
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36 | * can have its own base (starting index value: e.g. 0 for C-style arrays, |
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37 | * 1 for Fortran arrays). |
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38 | * |
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39 | * GeneralArrayStorage<N> defaults to C-style arrays. To implement |
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40 | * other storage formats, subclass and modify the constructor. The |
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41 | * class FortranArray, below, is an example. |
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42 | * |
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43 | * Objects inheriting from GeneralArrayStorage<N> can be passed as |
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44 | * an optional constructor argument to Array objects. |
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45 | * e.g. Array<int,3> A(16,16,16, FortranArray<3>()); |
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46 | * will create a 3-dimensional 16x16x16 Fortran-style array. |
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47 | */ |
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48 | |
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49 | template<int N_rank> |
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50 | class GeneralArrayStorage { |
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51 | public: |
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52 | class noInitializeFlag { }; |
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53 | |
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54 | GeneralArrayStorage(noInitializeFlag) |
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55 | { } |
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56 | |
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57 | GeneralArrayStorage() |
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58 | { |
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59 | for (int i=0; i < N_rank; ++i) |
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60 | ordering_(i) = N_rank - 1 - i; |
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61 | ascendingFlag_ = true; |
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62 | base_ = 0; |
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63 | } |
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64 | |
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65 | GeneralArrayStorage(const GeneralArrayStorage<N_rank>& x) |
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66 | : ordering_(x.ordering_), ascendingFlag_(x.ascendingFlag_), |
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67 | base_(x.base_) |
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68 | { |
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69 | } |
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70 | |
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71 | GeneralArrayStorage(TinyVector<int,N_rank> ordering, |
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72 | TinyVector<bool,N_rank> ascendingFlag) |
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73 | : ordering_(ordering), ascendingFlag_(ascendingFlag) |
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74 | { |
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75 | base_ = 0; |
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76 | } |
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77 | |
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78 | ~GeneralArrayStorage() |
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79 | { } |
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80 | |
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81 | GeneralArrayStorage<N_rank>& operator=( |
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82 | const GeneralArrayStorage<N_rank>& rhs) |
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83 | { |
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84 | ordering_ = rhs.ordering(); |
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85 | ascendingFlag_ = rhs.ascendingFlag(); |
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86 | base_ = rhs.base(); |
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87 | return *this; |
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88 | } |
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89 | |
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90 | TinyVector<int, N_rank>& ordering() |
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91 | { return ordering_; } |
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92 | |
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93 | const TinyVector<int, N_rank>& ordering() const |
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94 | { return ordering_; } |
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95 | |
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96 | int ordering(int i) const |
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97 | { return ordering_[i]; } |
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98 | |
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99 | void setOrdering(int i, int order) |
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100 | { ordering_[i] = order; } |
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101 | |
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102 | bool allRanksStoredAscending() const |
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103 | { |
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104 | bool result = true; |
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105 | for (int i=0; i < N_rank; ++i) |
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106 | result &= ascendingFlag_[i]; |
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107 | return result; |
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108 | } |
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109 | |
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110 | bool isRankStoredAscending(int i) const |
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111 | { return ascendingFlag_[i]; } |
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112 | |
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113 | TinyVector<bool, N_rank>& ascendingFlag() |
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114 | { return ascendingFlag_; } |
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115 | |
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116 | const TinyVector<bool, N_rank>& ascendingFlag() const |
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117 | { return ascendingFlag_; } |
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118 | |
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119 | void setAscendingFlag(int i, bool ascendingFlag) |
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120 | { ascendingFlag_[i] = ascendingFlag; } |
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121 | |
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122 | TinyVector<int, N_rank>& base() |
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123 | { return base_; } |
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124 | |
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125 | const TinyVector<int, N_rank>& base() const |
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126 | { return base_; } |
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127 | |
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128 | int base(int i) const |
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129 | { return base_[i]; } |
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130 | |
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131 | void setBase(int i, int base) |
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132 | { base_[i] = base; } |
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133 | |
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134 | void setBase(const TinyVector<int, N_rank>& base) |
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135 | { base_ = base; } |
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136 | |
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137 | protected: |
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138 | /* |
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139 | * ordering_[] specifies the order in which the array is stored in |
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140 | * memory. For a newly allocated array, ordering_(0) will give the |
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141 | * rank with unit stride, and ordering_(N_rank-1) will be the rank |
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142 | * with largest stride. An order like [2, 1, 0] corresponds to |
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143 | * C-style array storage; an order like [0, 1, 2] corresponds to |
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144 | * Fortran array storage. |
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145 | * |
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146 | * ascendingFlag_[] indicates whether the data in a rank is stored |
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147 | * in ascending or descending order. Most of the time these values |
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148 | * will all be true (indicating ascending order). Some peculiar |
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149 | * formats (e.g. MS-Windows BMP image format) store the data in |
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150 | * descending order. |
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151 | * |
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152 | * base_[] gives the first valid index for each rank. For a C-style |
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153 | * array, all the base_ elements will be zero; for a Fortran-style |
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154 | * array, they will be one. base_[] can be set arbitrarily using |
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155 | * the Array constructor which takes a Range argument, e.g. |
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156 | * Array<float,2> A(Range(30,40),Range(23,33)); |
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157 | * will create an array with base_[] = { 30, 23 }. |
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158 | */ |
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159 | TinyVector<int, N_rank> ordering_; |
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160 | TinyVector<bool, N_rank> ascendingFlag_; |
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161 | TinyVector<int, N_rank> base_; |
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162 | }; |
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163 | |
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164 | /* |
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165 | * Class FortranArray specializes GeneralArrayStorage to provide Fortran |
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166 | * style arrays (column major ordering, base of 1). The noInitializeFlag() |
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167 | * passed to the base constructor indicates that the subclass will take |
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168 | * care of initializing the ordering_, ascendingFlag_ and base_ members. |
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169 | */ |
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170 | |
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171 | template<int N_rank> |
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172 | class FortranArray : public GeneralArrayStorage<N_rank> { |
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173 | private: |
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174 | typedef GeneralArrayStorage<N_rank> T_base; |
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175 | typedef _bz_typename T_base::noInitializeFlag noInitializeFlag; |
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176 | using T_base::ordering_; |
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177 | using T_base::ascendingFlag_; |
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178 | using T_base::base_; |
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179 | public: |
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180 | FortranArray() |
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181 | : GeneralArrayStorage<N_rank>(noInitializeFlag()) |
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182 | { |
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183 | for (int i=0; i < N_rank; ++i) |
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184 | ordering_(i) = i; |
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185 | ascendingFlag_ = true; |
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186 | base_ = 1; |
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187 | } |
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188 | }; |
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189 | |
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190 | |
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191 | // This tag class can be used to provide a nicer notation for |
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192 | // constructing Fortran-style arrays: instead of |
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193 | // Array<int,2> A(3, 3, FortranArray<2>()); |
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194 | // one can simply write: |
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195 | // Array<int,2> A(3, 3, fortranArray); |
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196 | // where fortranArray is an object of type _bz_fortranTag. |
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197 | |
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198 | class _bz_fortranTag { |
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199 | public: |
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200 | operator GeneralArrayStorage<1>() |
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201 | { return FortranArray<1>(); } |
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202 | |
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203 | operator GeneralArrayStorage<2>() |
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204 | { return FortranArray<2>(); } |
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205 | |
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206 | operator GeneralArrayStorage<3>() |
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207 | { return FortranArray<3>(); } |
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208 | |
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209 | operator GeneralArrayStorage<4>() |
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210 | { return FortranArray<4>(); } |
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211 | |
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212 | operator GeneralArrayStorage<5>() |
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213 | { return FortranArray<5>(); } |
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214 | |
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215 | operator GeneralArrayStorage<6>() |
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216 | { return FortranArray<6>(); } |
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217 | |
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218 | operator GeneralArrayStorage<7>() |
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219 | { return FortranArray<7>(); } |
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220 | |
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221 | operator GeneralArrayStorage<8>() |
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222 | { return FortranArray<8>(); } |
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223 | |
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224 | operator GeneralArrayStorage<9>() |
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225 | { return FortranArray<9>(); } |
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226 | |
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227 | operator GeneralArrayStorage<10>() |
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228 | { return FortranArray<10>(); } |
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229 | |
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230 | operator GeneralArrayStorage<11>() |
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231 | { return FortranArray<11>(); } |
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232 | }; |
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233 | |
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234 | // A global instance of this class will be placed in |
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235 | // the blitz library (libblitz.a on unix machines). |
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236 | |
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237 | _bz_global _bz_fortranTag fortranArray; |
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238 | |
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239 | |
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240 | /* |
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241 | * Class ColumnMajorArray specializes GeneralArrayStorage to provide column |
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242 | * major arrays (column major ordering, base of 0). |
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243 | */ |
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244 | |
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245 | template<int N_rank> |
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246 | class ColumnMajorArray : public GeneralArrayStorage<N_rank> { |
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247 | private: |
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248 | typedef GeneralArrayStorage<N_rank> T_base; |
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249 | typedef _bz_typename T_base::noInitializeFlag noInitializeFlag; |
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250 | using T_base::ordering_; |
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251 | using T_base::ascendingFlag_; |
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252 | using T_base::base_; |
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253 | public: |
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254 | ColumnMajorArray() |
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255 | : GeneralArrayStorage<N_rank>(noInitializeFlag()) |
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256 | { |
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257 | ordering_ = Range(0, N_rank - 1); |
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258 | ascendingFlag_ = true; |
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259 | base_ = 0; |
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260 | } |
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261 | }; |
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262 | |
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263 | BZ_NAMESPACE_END |
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264 | |
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265 | #endif // BZ_ARRAY_STORAGE_H |
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266 | |
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