1 | /*************************************************************************** |
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2 | * blitz/matltri.h Declarations for LowerTriangular matrices |
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3 | * |
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4 | * $Id: matltri.h,v 1.4 2003/12/11 03:44:22 julianc Exp $ |
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5 | * |
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6 | * Copyright (C) 1997-2001 Todd Veldhuizen <tveldhui@oonumerics.org> |
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7 | * |
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8 | * This program is free software; you can redistribute it and/or |
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9 | * modify it under the terms of the GNU General Public License |
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10 | * as published by the Free Software Foundation; either version 2 |
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11 | * of the License, or (at your option) any later version. |
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12 | * |
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13 | * This program is distributed in the hope that it will be useful, |
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | * GNU General Public License for more details. |
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17 | * |
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18 | * Suggestions: blitz-dev@oonumerics.org |
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19 | * Bugs: blitz-bugs@oonumerics.org |
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20 | * |
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21 | * For more information, please see the Blitz++ Home Page: |
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22 | * http://oonumerics.org/blitz/ |
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23 | * |
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24 | ***************************************************************************/ |
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25 | |
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26 | |
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27 | #ifndef BZ_MATLTRI_H |
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28 | #define BZ_MATLTRI_H |
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29 | |
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30 | #ifndef BZ_MSTRUCT_H |
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31 | #error <blitz/matltri.h> must be included via <blitz/mstruct.h> |
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32 | #endif |
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33 | |
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34 | BZ_NAMESPACE(blitz) |
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35 | |
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36 | // Lower triangular, row major ordering |
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37 | // [ 0 . . . ] |
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38 | // [ 1 2 . . ] |
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39 | // [ 3 4 5 . ] |
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40 | // [ 6 7 8 9 ] |
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41 | |
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42 | class LowerTriangularIterator { |
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43 | public: |
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44 | LowerTriangularIterator(unsigned rows, unsigned cols) |
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45 | { |
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46 | BZPRECONDITION(rows == cols); |
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47 | size_ = rows; |
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48 | good_ = true; |
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49 | offset_ = 0; |
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50 | i_ = 0; |
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51 | j_ = 0; |
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52 | } |
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53 | |
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54 | operator bool() const { return good_; } |
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55 | |
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56 | void operator++() |
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57 | { |
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58 | BZPRECONDITION(good_); |
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59 | ++offset_; |
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60 | ++j_; |
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61 | if (j_ > i_) |
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62 | { |
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63 | j_ = 0; |
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64 | ++i_; |
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65 | if (i_ == size_) |
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66 | good_ = false; |
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67 | } |
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68 | } |
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69 | |
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70 | unsigned row() const |
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71 | { return i_; } |
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72 | |
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73 | unsigned col() const |
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74 | { return j_; } |
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75 | |
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76 | unsigned offset() const |
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77 | { return offset_; } |
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78 | |
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79 | protected: |
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80 | unsigned size_; |
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81 | bool good_; |
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82 | unsigned offset_; |
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83 | unsigned i_, j_; |
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84 | }; |
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85 | |
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86 | class LowerTriangular : public MatrixStructure { |
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87 | |
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88 | public: |
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89 | typedef LowerTriangularIterator T_iterator; |
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90 | |
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91 | LowerTriangular() |
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92 | : size_(0) |
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93 | { } |
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94 | |
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95 | LowerTriangular(unsigned size) |
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96 | : size_(size) |
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97 | { } |
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98 | |
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99 | LowerTriangular(unsigned rows, unsigned cols) |
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100 | : size_(rows) |
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101 | { |
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102 | BZPRECONDITION(rows == cols); |
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103 | } |
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104 | |
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105 | unsigned columns() const |
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106 | { return size_; } |
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107 | |
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108 | unsigned coordToOffset(unsigned i, unsigned j) const |
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109 | { |
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110 | BZPRECONDITION(inRange(i,j)); |
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111 | BZPRECONDITION(i >= j); |
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112 | return i*(i+1)/2 + j; |
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113 | } |
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114 | |
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115 | unsigned firstInRow(unsigned i) const |
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116 | { return 0; } |
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117 | |
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118 | template<typename T_numtype> |
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119 | T_numtype get(const T_numtype * restrict data, |
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120 | unsigned i, unsigned j) const |
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121 | { |
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122 | BZPRECONDITION(inRange(i,j)); |
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123 | if (i >= j) |
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124 | return data[coordToOffset(i,j)]; |
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125 | else |
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126 | return ZeroElement<T_numtype>::zero(); |
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127 | } |
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128 | |
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129 | template<typename T_numtype> |
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130 | T_numtype& get(T_numtype * restrict data, unsigned i, unsigned j) |
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131 | { |
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132 | BZPRECONDITION(inRange(i,j)); |
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133 | if (i >= j) |
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134 | return data[coordToOffset(i,j)]; |
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135 | else |
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136 | return ZeroElement<T_numtype>::zero(); |
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137 | } |
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138 | |
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139 | unsigned lastInRow(unsigned i) const |
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140 | { return i; } |
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141 | |
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142 | unsigned firstInCol(unsigned j) const |
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143 | { return j; } |
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144 | |
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145 | unsigned lastInCol(unsigned j) const |
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146 | { return size_ - 1; } |
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147 | |
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148 | bool inRange(unsigned i, unsigned j) const |
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149 | { |
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150 | return (i < size_) && (j < size_); |
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151 | } |
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152 | |
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153 | unsigned numElements() const |
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154 | { return size_ * (size_ + 1) / 2; } |
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155 | |
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156 | unsigned rows() const |
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157 | { return size_; } |
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158 | |
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159 | void resize(unsigned size) |
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160 | { |
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161 | size_ = size; |
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162 | } |
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163 | |
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164 | void resize(unsigned rows, unsigned cols) |
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165 | { |
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166 | BZPRECONDITION(rows == cols); |
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167 | size_ = rows; |
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168 | } |
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169 | |
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170 | private: |
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171 | unsigned size_; |
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172 | }; |
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173 | |
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174 | BZ_NAMESPACE_END |
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175 | |
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176 | #endif // BZ_MATLTRI_H |
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177 | |
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