1 | Module m_mrgrnk |
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2 | IMPLICIT NONE |
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3 | Integer, Parameter :: kdp = selected_real_kind(15) |
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4 | public :: mrgrnk |
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5 | private :: kdp |
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6 | private :: I_mrgrnk, D_mrgrnk |
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7 | interface mrgrnk |
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8 | module procedure D_mrgrnk, I_mrgrnk |
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9 | end interface mrgrnk |
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10 | contains |
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11 | |
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12 | Subroutine D_mrgrnk (XDONT, IRNGT) |
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13 | ! __________________________________________________________ |
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14 | ! MRGRNK = Merge-sort ranking of an array |
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15 | ! For performance reasons, the first 2 passes are taken |
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16 | ! out of the standard loop, and use dedicated coding. |
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17 | ! __________________________________________________________ |
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18 | ! __________________________________________________________ |
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19 | Real (kind=kdp), Dimension (:), Intent (In) :: XDONT |
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20 | Integer, Dimension (:), Intent (Out) :: IRNGT |
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21 | ! __________________________________________________________ |
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22 | Real (kind=kdp) :: XVALA, XVALB |
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23 | |
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24 | Integer, Dimension (SIZE(IRNGT)) :: JWRKT |
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25 | Integer :: LMTNA, LMTNC, IRNG1, IRNG2 |
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26 | Integer :: NVAL, IIND, IWRKD, IWRK, IWRKF, JINDA, IINDA, IINDB |
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27 | |
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28 | NVAL = Min (SIZE(XDONT), SIZE(IRNGT)) |
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29 | Select Case (NVAL) |
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30 | Case (:0) |
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31 | Return |
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32 | Case (1) |
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33 | IRNGT (1) = 1 |
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34 | Return |
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35 | Case Default |
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36 | Continue |
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37 | End Select |
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38 | |
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39 | ! Fill-in the index array, creating ordered couples |
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40 | |
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41 | Do IIND = 2, NVAL, 2 |
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42 | If (XDONT(IIND-1) <= XDONT(IIND)) Then |
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43 | IRNGT (IIND-1) = IIND - 1 |
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44 | IRNGT (IIND) = IIND |
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45 | Else |
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46 | IRNGT (IIND-1) = IIND |
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47 | IRNGT (IIND) = IIND - 1 |
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48 | End If |
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49 | End Do |
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50 | If (Modulo(NVAL, 2) /= 0) Then |
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51 | IRNGT (NVAL) = NVAL |
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52 | End If |
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53 | |
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54 | ! We will now have ordered subsets A - B - A - B - ... |
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55 | ! and merge A and B couples into C - C - ... |
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56 | |
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57 | LMTNA = 2 |
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58 | LMTNC = 4 |
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59 | |
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60 | ! First iteration. The length of the ordered subsets goes from 2 to 4 |
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61 | |
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62 | Do |
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63 | If (NVAL <= 2) Exit |
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64 | |
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65 | ! Loop on merges of A and B into C |
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66 | |
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67 | Do IWRKD = 0, NVAL - 1, 4 |
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68 | If ((IWRKD+4) > NVAL) Then |
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69 | If ((IWRKD+2) >= NVAL) Exit |
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70 | |
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71 | ! 1 2 3 |
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72 | |
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73 | If (XDONT(IRNGT(IWRKD+2)) <= XDONT(IRNGT(IWRKD+3))) Exit |
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74 | |
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75 | ! 1 3 2 |
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76 | |
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77 | If (XDONT(IRNGT(IWRKD+1)) <= XDONT(IRNGT(IWRKD+3))) Then |
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78 | IRNG2 = IRNGT (IWRKD+2) |
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79 | IRNGT (IWRKD+2) = IRNGT (IWRKD+3) |
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80 | IRNGT (IWRKD+3) = IRNG2 |
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81 | |
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82 | ! 3 1 2 |
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83 | |
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84 | Else |
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85 | IRNG1 = IRNGT (IWRKD+1) |
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86 | IRNGT (IWRKD+1) = IRNGT (IWRKD+3) |
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87 | IRNGT (IWRKD+3) = IRNGT (IWRKD+2) |
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88 | IRNGT (IWRKD+2) = IRNG1 |
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89 | End If |
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90 | Exit |
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91 | End If |
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92 | |
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93 | ! 1 2 3 4 |
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94 | |
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95 | If (XDONT(IRNGT(IWRKD+2)) <= XDONT(IRNGT(IWRKD+3))) Cycle |
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96 | |
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97 | ! 1 3 x x |
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98 | |
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99 | If (XDONT(IRNGT(IWRKD+1)) <= XDONT(IRNGT(IWRKD+3))) Then |
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100 | IRNG2 = IRNGT (IWRKD+2) |
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101 | IRNGT (IWRKD+2) = IRNGT (IWRKD+3) |
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102 | If (XDONT(IRNG2) <= XDONT(IRNGT(IWRKD+4))) Then |
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103 | ! 1 3 2 4 |
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104 | IRNGT (IWRKD+3) = IRNG2 |
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105 | Else |
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106 | ! 1 3 4 2 |
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107 | IRNGT (IWRKD+3) = IRNGT (IWRKD+4) |
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108 | IRNGT (IWRKD+4) = IRNG2 |
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109 | End If |
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110 | |
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111 | ! 3 x x x |
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112 | |
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113 | Else |
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114 | IRNG1 = IRNGT (IWRKD+1) |
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115 | IRNG2 = IRNGT (IWRKD+2) |
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116 | IRNGT (IWRKD+1) = IRNGT (IWRKD+3) |
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117 | If (XDONT(IRNG1) <= XDONT(IRNGT(IWRKD+4))) Then |
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118 | IRNGT (IWRKD+2) = IRNG1 |
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119 | If (XDONT(IRNG2) <= XDONT(IRNGT(IWRKD+4))) Then |
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120 | ! 3 1 2 4 |
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121 | IRNGT (IWRKD+3) = IRNG2 |
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122 | Else |
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123 | ! 3 1 4 2 |
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124 | IRNGT (IWRKD+3) = IRNGT (IWRKD+4) |
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125 | IRNGT (IWRKD+4) = IRNG2 |
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126 | End If |
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127 | Else |
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128 | ! 3 4 1 2 |
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129 | IRNGT (IWRKD+2) = IRNGT (IWRKD+4) |
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130 | IRNGT (IWRKD+3) = IRNG1 |
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131 | IRNGT (IWRKD+4) = IRNG2 |
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132 | End If |
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133 | End If |
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134 | End Do |
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135 | |
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136 | ! The Cs become As and Bs |
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137 | |
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138 | LMTNA = 4 |
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139 | Exit |
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140 | End Do |
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141 | |
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142 | ! Iteration loop. Each time, the length of the ordered subsets |
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143 | ! is doubled. |
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144 | |
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145 | Do |
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146 | If (LMTNA >= NVAL) Exit |
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147 | IWRKF = 0 |
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148 | LMTNC = 2 * LMTNC |
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149 | |
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150 | ! Loop on merges of A and B into C |
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151 | |
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152 | Do |
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153 | IWRK = IWRKF |
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154 | IWRKD = IWRKF + 1 |
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155 | JINDA = IWRKF + LMTNA |
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156 | IWRKF = IWRKF + LMTNC |
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157 | If (IWRKF >= NVAL) Then |
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158 | If (JINDA >= NVAL) Exit |
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159 | IWRKF = NVAL |
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160 | End If |
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161 | IINDA = 1 |
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162 | IINDB = JINDA + 1 |
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163 | |
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164 | ! Shortcut for the case when the max of A is smaller |
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165 | ! than the min of B. This line may be activated when the |
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166 | ! initial set is already close to sorted. |
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167 | |
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168 | ! IF (XDONT(IRNGT(JINDA)) <= XDONT(IRNGT(IINDB))) CYCLE |
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169 | |
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170 | ! One steps in the C subset, that we build in the final rank array |
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171 | |
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172 | ! Make a copy of the rank array for the merge iteration |
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173 | |
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174 | JWRKT (1:LMTNA) = IRNGT (IWRKD:JINDA) |
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175 | |
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176 | XVALA = XDONT (JWRKT(IINDA)) |
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177 | XVALB = XDONT (IRNGT(IINDB)) |
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178 | |
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179 | Do |
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180 | IWRK = IWRK + 1 |
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181 | |
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182 | ! We still have unprocessed values in both A and B |
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183 | |
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184 | If (XVALA > XVALB) Then |
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185 | IRNGT (IWRK) = IRNGT (IINDB) |
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186 | IINDB = IINDB + 1 |
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187 | If (IINDB > IWRKF) Then |
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188 | ! Only A still with unprocessed values |
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189 | IRNGT (IWRK+1:IWRKF) = JWRKT (IINDA:LMTNA) |
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190 | Exit |
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191 | End If |
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192 | XVALB = XDONT (IRNGT(IINDB)) |
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193 | Else |
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194 | IRNGT (IWRK) = JWRKT (IINDA) |
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195 | IINDA = IINDA + 1 |
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196 | If (IINDA > LMTNA) Exit! Only B still with unprocessed values |
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197 | XVALA = XDONT (JWRKT(IINDA)) |
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198 | End If |
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199 | |
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200 | End Do |
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201 | End Do |
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202 | |
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203 | ! The Cs become As and Bs |
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204 | |
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205 | LMTNA = 2 * LMTNA |
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206 | End Do |
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207 | |
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208 | Return |
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209 | |
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210 | End Subroutine D_mrgrnk |
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211 | |
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212 | Subroutine I_mrgrnk (XDONT, IRNGT) |
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213 | ! __________________________________________________________ |
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214 | ! MRGRNK = Merge-sort ranking of an array |
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215 | ! For performance reasons, the first 2 passes are taken |
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216 | ! out of the standard loop, and use dedicated coding. |
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217 | ! __________________________________________________________ |
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218 | ! __________________________________________________________ |
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219 | Integer, Dimension (:), Intent (In) :: XDONT |
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220 | Integer, Dimension (:), Intent (Out) :: IRNGT |
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221 | ! __________________________________________________________ |
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222 | Integer :: XVALA, XVALB |
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223 | |
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224 | Integer, Dimension (SIZE(IRNGT)) :: JWRKT |
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225 | Integer :: LMTNA, LMTNC, IRNG1, IRNG2 |
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226 | Integer :: NVAL, IIND, IWRKD, IWRK, IWRKF, JINDA, IINDA, IINDB |
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227 | |
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228 | NVAL = Min (SIZE(XDONT), SIZE(IRNGT)) |
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229 | Select Case (NVAL) |
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230 | Case (:0) |
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231 | Return |
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232 | Case (1) |
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233 | IRNGT (1) = 1 |
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234 | Return |
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235 | Case Default |
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236 | Continue |
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237 | End Select |
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238 | |
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239 | ! Fill-in the index array, creating ordered couples |
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240 | |
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241 | Do IIND = 2, NVAL, 2 |
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242 | If (XDONT(IIND-1) <= XDONT(IIND)) Then |
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243 | IRNGT (IIND-1) = IIND - 1 |
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244 | IRNGT (IIND) = IIND |
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245 | Else |
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246 | IRNGT (IIND-1) = IIND |
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247 | IRNGT (IIND) = IIND - 1 |
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248 | End If |
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249 | End Do |
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250 | If (Modulo(NVAL, 2) /= 0) Then |
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251 | IRNGT (NVAL) = NVAL |
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252 | End If |
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253 | |
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254 | ! We will now have ordered subsets A - B - A - B - ... |
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255 | ! and merge A and B couples into C - C - ... |
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256 | |
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257 | LMTNA = 2 |
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258 | LMTNC = 4 |
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259 | |
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260 | ! First iteration. The length of the ordered subsets goes from 2 to 4 |
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261 | |
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262 | Do |
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263 | If (NVAL <= 2) Exit |
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264 | |
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265 | ! Loop on merges of A and B into C |
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266 | |
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267 | Do IWRKD = 0, NVAL - 1, 4 |
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268 | If ((IWRKD+4) > NVAL) Then |
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269 | If ((IWRKD+2) >= NVAL) Exit |
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270 | |
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271 | ! 1 2 3 |
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272 | |
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273 | If (XDONT(IRNGT(IWRKD+2)) <= XDONT(IRNGT(IWRKD+3))) Exit |
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274 | |
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275 | ! 1 3 2 |
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276 | |
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277 | If (XDONT(IRNGT(IWRKD+1)) <= XDONT(IRNGT(IWRKD+3))) Then |
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278 | IRNG2 = IRNGT (IWRKD+2) |
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279 | IRNGT (IWRKD+2) = IRNGT (IWRKD+3) |
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280 | IRNGT (IWRKD+3) = IRNG2 |
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281 | |
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282 | ! 3 1 2 |
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283 | |
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284 | Else |
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285 | IRNG1 = IRNGT (IWRKD+1) |
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286 | IRNGT (IWRKD+1) = IRNGT (IWRKD+3) |
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287 | IRNGT (IWRKD+3) = IRNGT (IWRKD+2) |
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288 | IRNGT (IWRKD+2) = IRNG1 |
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289 | End If |
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290 | Exit |
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291 | End If |
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292 | |
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293 | ! 1 2 3 4 |
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294 | |
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295 | If (XDONT(IRNGT(IWRKD+2)) <= XDONT(IRNGT(IWRKD+3))) Cycle |
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296 | |
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297 | ! 1 3 x x |
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298 | |
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299 | If (XDONT(IRNGT(IWRKD+1)) <= XDONT(IRNGT(IWRKD+3))) Then |
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300 | IRNG2 = IRNGT (IWRKD+2) |
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301 | IRNGT (IWRKD+2) = IRNGT (IWRKD+3) |
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302 | If (XDONT(IRNG2) <= XDONT(IRNGT(IWRKD+4))) Then |
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303 | ! 1 3 2 4 |
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304 | IRNGT (IWRKD+3) = IRNG2 |
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305 | Else |
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306 | ! 1 3 4 2 |
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307 | IRNGT (IWRKD+3) = IRNGT (IWRKD+4) |
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308 | IRNGT (IWRKD+4) = IRNG2 |
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309 | End If |
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310 | |
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311 | ! 3 x x x |
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312 | |
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313 | Else |
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314 | IRNG1 = IRNGT (IWRKD+1) |
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315 | IRNG2 = IRNGT (IWRKD+2) |
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316 | IRNGT (IWRKD+1) = IRNGT (IWRKD+3) |
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317 | If (XDONT(IRNG1) <= XDONT(IRNGT(IWRKD+4))) Then |
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318 | IRNGT (IWRKD+2) = IRNG1 |
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319 | If (XDONT(IRNG2) <= XDONT(IRNGT(IWRKD+4))) Then |
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320 | ! 3 1 2 4 |
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321 | IRNGT (IWRKD+3) = IRNG2 |
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322 | Else |
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323 | ! 3 1 4 2 |
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324 | IRNGT (IWRKD+3) = IRNGT (IWRKD+4) |
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325 | IRNGT (IWRKD+4) = IRNG2 |
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326 | End If |
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327 | Else |
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328 | ! 3 4 1 2 |
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329 | IRNGT (IWRKD+2) = IRNGT (IWRKD+4) |
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330 | IRNGT (IWRKD+3) = IRNG1 |
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331 | IRNGT (IWRKD+4) = IRNG2 |
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332 | End If |
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333 | End If |
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334 | End Do |
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335 | |
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336 | ! The Cs become As and Bs |
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337 | |
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338 | LMTNA = 4 |
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339 | Exit |
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340 | End Do |
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341 | |
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342 | ! Iteration loop. Each time, the length of the ordered subsets |
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343 | ! is doubled. |
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344 | |
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345 | Do |
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346 | If (LMTNA >= NVAL) Exit |
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347 | IWRKF = 0 |
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348 | LMTNC = 2 * LMTNC |
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349 | |
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350 | ! Loop on merges of A and B into C |
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351 | |
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352 | Do |
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353 | IWRK = IWRKF |
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354 | IWRKD = IWRKF + 1 |
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355 | JINDA = IWRKF + LMTNA |
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356 | IWRKF = IWRKF + LMTNC |
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357 | If (IWRKF >= NVAL) Then |
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358 | If (JINDA >= NVAL) Exit |
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359 | IWRKF = NVAL |
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360 | End If |
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361 | IINDA = 1 |
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362 | IINDB = JINDA + 1 |
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363 | |
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364 | ! Shortcut for the case when the max of A is smaller |
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365 | ! than the min of B. This line may be activated when the |
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366 | ! initial set is already close to sorted. |
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367 | |
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368 | ! IF (XDONT(IRNGT(JINDA)) <= XDONT(IRNGT(IINDB))) CYCLE |
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369 | |
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370 | ! One steps in the C subset, that we build in the final rank array |
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371 | |
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372 | ! Make a copy of the rank array for the merge iteration |
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373 | |
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374 | JWRKT (1:LMTNA) = IRNGT (IWRKD:JINDA) |
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375 | |
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376 | XVALA = XDONT (JWRKT(IINDA)) |
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377 | XVALB = XDONT (IRNGT(IINDB)) |
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378 | |
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379 | Do |
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380 | IWRK = IWRK + 1 |
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381 | |
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382 | ! We still have unprocessed values in both A and B |
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383 | |
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384 | If (XVALA > XVALB) Then |
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385 | IRNGT (IWRK) = IRNGT (IINDB) |
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386 | IINDB = IINDB + 1 |
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387 | If (IINDB > IWRKF) Then |
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388 | ! Only A still with unprocessed values |
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389 | IRNGT (IWRK+1:IWRKF) = JWRKT (IINDA:LMTNA) |
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390 | Exit |
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391 | End If |
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392 | XVALB = XDONT (IRNGT(IINDB)) |
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393 | Else |
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394 | IRNGT (IWRK) = JWRKT (IINDA) |
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395 | IINDA = IINDA + 1 |
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396 | If (IINDA > LMTNA) Exit! Only B still with unprocessed values |
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397 | XVALA = XDONT (JWRKT(IINDA)) |
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398 | End If |
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399 | |
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400 | End Do |
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401 | End Do |
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402 | |
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403 | ! The Cs become As and Bs |
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404 | |
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405 | LMTNA = 2 * LMTNA |
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406 | End Do |
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407 | |
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408 | Return |
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409 | |
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410 | End Subroutine I_mrgrnk |
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411 | end module m_mrgrnk |
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