1 | subroutine gradient_bicubic(NX1, NY1, src_array, sou_mask, & |
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2 | src_latitudes, src_longitudes, & |
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3 | id_per, cd_per, & |
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4 | gradient_i, gradient_j, gradient_ij) |
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5 | !**** |
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6 | ! ***************************** |
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7 | ! * OASIS ROUTINE - LEVEL ? * |
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8 | ! * ------------- ------- * |
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9 | ! ***************************** |
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10 | ! |
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11 | !**** *gradient_bicubic* - calculate gradients for bicubic remapping |
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12 | ! |
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13 | ! Purpose: |
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14 | ! ------- |
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15 | ! Calculation of gradients for bicubic interpolation. In contrast to |
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16 | ! the gradients of conservative remapping, these gradients are |
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17 | ! calculated with respect to grid rows and grid lines. |
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18 | ! |
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19 | !** Interface: |
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20 | ! --------- |
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21 | ! *CALL* *gradient_bicubic*(NX1, NY1, src_array, sou_mask, |
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22 | ! src_latitudes, src_longitudes, |
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23 | ! gradient_i, gradient_j, gradient_ij) |
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24 | ! |
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25 | ! Input: |
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26 | ! ----- |
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27 | ! NX1 : grid dimension in x-direction (integer) |
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28 | ! NY1 : grid dimension in y-direction (integer) |
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29 | ! src_array : array on source grid (real 2D) |
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30 | ! sou_mask : source grid mask (integer 2D) |
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31 | ! src_latitudes : latitudes on source grid (real 2D) |
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32 | ! src_longitudes : longitudes on source grid (real 2D) |
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33 | ! id_per : number of overlapping points for source grid |
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34 | ! cd_per : grip periodicity type |
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35 | ! |
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36 | ! Output: |
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37 | ! ------ |
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38 | ! gradient_i : gradient in i-direction (real 2D) |
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39 | ! gradient_j : gradient in j-direction (real 2D) |
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40 | ! gradient_ij : gradient in ij-direction (real 2D) |
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41 | ! |
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42 | ! History: |
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43 | ! ------- |
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44 | ! Version Programmer Date Description |
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45 | ! ------- ---------- ---- ----------- |
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46 | ! 2.5 V. Gayler 2002/04/05 created |
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47 | ! |
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48 | ! %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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49 | |
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50 | IMPLICIT NONE |
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51 | |
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52 | INTEGER, PARAMETER :: wp = SELECTED_REAL_KIND(12,307) ! double |
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53 | !----------------------------------------------------------------------- |
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54 | ! INTENT(IN) |
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55 | !----------------------------------------------------------------------- |
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56 | INTEGER, INTENT(IN) :: & |
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57 | NX1, NY1, & ! source grid dimensiones |
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58 | id_per ! nbr of overlapping grid points |
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59 | |
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60 | CHARACTER(len=8), INTENT(IN) :: & |
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61 | cd_per ! grip periodicity type |
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62 | |
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63 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(IN) :: & |
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64 | src_array ! array on source grid |
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65 | |
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66 | INTEGER, DIMENSION(NX1,NY1), INTENT(IN) :: & |
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67 | sou_mask ! source grid mask |
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68 | |
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69 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(IN) :: & |
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70 | src_latitudes, & ! source grid latitudes |
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71 | src_longitudes ! source grid longitudes |
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72 | |
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73 | !----------------------------------------------------------------------- |
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74 | ! INTENT(OUT) |
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75 | !----------------------------------------------------------------------- |
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76 | REAL (kind=wp), DIMENSION(NX1,NY1), INTENT(OUT) :: & |
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77 | gradient_i, & ! gradient in i-direction (real 2D) |
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78 | gradient_j, & ! gradient in j-direction (real 2D) |
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79 | gradient_ij ! gradient in ij-direction (real 2D) |
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80 | |
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81 | !----------------------------------------------------------------------- |
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82 | ! LOCAL VARIABLES |
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83 | !----------------------------------------------------------------------- |
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84 | INTEGER :: & |
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85 | i, j, & ! looping indicees |
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86 | ip1, jp1, im1, jm1 |
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87 | |
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88 | REAL (kind=wp) :: & |
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89 | di, dj, & ! factor depending on grid cell distance |
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90 | gradient_ij1, & ! gradient needed to calculate gradient_ij |
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91 | gradient_ij2 ! gradient needed to calculate gradient_ij |
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92 | |
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93 | REAL (kind=wp), DIMENSION(NX1,NY1) :: & |
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94 | src_lon, & ! source grid longitudes [radiants] |
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95 | src_lat, & ! source grid latitudes [radiants] |
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96 | pi180 ! conversion factor: deg -> rad |
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97 | |
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98 | INTEGER, PARAMETER :: il_maskval= 1 ! in our grids sea_value = 0 and land_value = 1 |
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99 | |
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100 | !---------------------------------------------------------------------- |
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101 | ! |
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102 | ! Transformation from degree to radiant |
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103 | ! ------------------------------------- |
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104 | pi180 = 1.74532925199432957692e-2 ! =PI/180 |
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105 | |
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106 | src_lon = src_longitudes * pi180 |
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107 | src_lat = src_latitudes * pi180 |
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108 | |
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109 | ! Initialization |
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110 | ! -------------- |
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111 | gradient_i = 0. |
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112 | gradient_j = 0. |
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113 | gradient_ij = 0. |
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114 | |
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115 | ! calculate gradients |
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116 | ! ------------------- |
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117 | DO i = 1, NX1 |
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118 | DO j = 1, NY1 |
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119 | |
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120 | IF (sou_mask (i,j) /= il_maskval) THEN |
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121 | |
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122 | di = 0.5 |
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123 | dj = 0.5 |
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124 | |
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125 | ip1 = i + 1 |
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126 | im1 = i - 1 |
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127 | IF (i == NX1) THEN |
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128 | IF (cd_per == 'P') ip1 = 1 + id_per ! the 0-meridian |
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129 | IF (cd_per == 'R') ip1 = NX1 |
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130 | ENDIF |
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131 | IF (i == 1 ) THEN |
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132 | IF (cd_per == 'P') im1 = NX1 - id_per |
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133 | IF (cd_per == 'R') im1 = 1 |
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134 | ENDIF |
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135 | jp1 = j + 1 |
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136 | jm1 = j - 1 |
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137 | IF (j == NY1) THEN ! treatment of the last.. |
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138 | jp1 = NY1 |
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139 | dj = 1. |
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140 | ENDIF |
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141 | IF (j == 1 ) THEN ! .. and the first grid-row |
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142 | jm1 = 1 |
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143 | dj = 1. |
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144 | ENDIF |
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145 | |
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146 | |
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147 | ! gradient i |
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148 | ! ---------- |
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149 | IF (sou_mask(ip1,j) /= il_maskval .OR. & |
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150 | sou_mask(im1,j) /= il_maskval) THEN |
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151 | IF (sou_mask(ip1,j) == il_maskval) THEN |
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152 | ip1 = i |
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153 | di = 1. |
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154 | ELSE IF (sou_mask(im1,j) == il_maskval) THEN |
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155 | im1 = i |
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156 | di = 1. |
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157 | ENDIF |
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158 | gradient_i(i,j) = di * (src_array(ip1,j) - src_array(im1,j)) |
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159 | ENDIF |
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160 | |
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161 | ! gradient j |
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162 | ! ---------- |
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163 | IF (sou_mask(i,jp1) /= il_maskval .OR. & |
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164 | sou_mask(i,jm1) /= il_maskval) THEN |
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165 | IF (sou_mask(i,jp1) == il_maskval) THEN |
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166 | jp1 = j |
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167 | dj = 1. |
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168 | ELSE IF (sou_mask(i,jm1) == il_maskval) THEN |
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169 | jm1 = j |
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170 | dj = 1. |
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171 | ENDIF |
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172 | gradient_j(i,j) = dj * (src_array(i,jp1) - src_array(i,jm1)) |
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173 | ENDIF |
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174 | ! |
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175 | ! gradient ij |
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176 | ! ----------- |
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177 | di = 0.5 |
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178 | dj = 0.5 |
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179 | ip1 = i + 1 |
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180 | im1 = i - 1 |
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181 | IF (i == NX1) THEN |
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182 | IF (cd_per == 'P') ip1 = 1 + id_per ! the 0-meridian |
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183 | IF (cd_per == 'R') ip1 = NX1 |
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184 | ENDIF |
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185 | IF (i == 1 ) THEN |
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186 | IF (cd_per == 'P') im1 = NX1 - id_per |
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187 | IF (cd_per == 'R') im1 = 1 |
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188 | ENDIF |
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189 | jp1 = j + 1 |
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190 | jm1 = j - 1 |
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191 | IF (j == NY1) THEN ! treatment of the last.. |
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192 | jp1 = NY1 |
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193 | dj = 1. |
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194 | ENDIF |
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195 | IF (j == 1 ) THEN ! .. and the first grid-row |
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196 | jm1 = 1 |
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197 | dj = 1. |
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198 | ENDIF |
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199 | |
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200 | gradient_ij1 = 0. |
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201 | IF (sou_mask(ip1,jp1) /= il_maskval .OR. & |
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202 | sou_mask(im1,jp1) /= il_maskval) THEN |
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203 | IF (sou_mask(ip1,jp1) == il_maskval .AND. & |
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204 | sou_mask(i,jp1) /= il_maskval) THEN |
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205 | ip1 = i |
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206 | di = 1. |
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207 | ELSE IF (sou_mask(im1,jp1) == il_maskval .AND. & |
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208 | sou_mask(i,jp1) /= il_maskval) THEN |
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209 | im1 = i |
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210 | di = 1. |
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211 | ELSE |
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212 | di = 0. |
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213 | ENDIF |
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214 | gradient_ij1 = di * (src_array(ip1,jp1) - src_array(im1,jp1)) |
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215 | ENDIF |
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216 | |
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217 | di = 0.5 |
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218 | ip1 = i + 1 |
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219 | im1 = i - 1 |
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220 | IF (i == NX1) THEN |
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221 | IF (cd_per == 'P') ip1 = 1 + id_per ! the 0-meridian |
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222 | IF (cd_per == 'R') ip1 = NX1 |
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223 | ENDIF |
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224 | IF (i == 1) THEN |
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225 | IF (cd_per == 'P') im1 = NX1 - id_per |
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226 | IF (cd_per == 'R') im1 = 1 |
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227 | ENDIF |
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228 | gradient_ij2 = 0. |
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229 | IF (sou_mask(ip1,jm1) /= il_maskval .OR. & |
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230 | sou_mask(im1,jm1) /= il_maskval) THEN |
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231 | IF (sou_mask(ip1,jm1) == il_maskval .AND. & |
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232 | sou_mask(i,jm1) /= il_maskval) THEN |
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233 | ip1 = i |
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234 | di = 1. |
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235 | ELSE IF (sou_mask(im1,jm1) == il_maskval .AND. & |
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236 | sou_mask(i,jm1) /= il_maskval) THEN |
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237 | im1 = i |
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238 | di = 1. |
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239 | ELSE |
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240 | di = 0. |
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241 | ENDIF |
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242 | gradient_ij2 = di * (src_array(ip1,jm1) - src_array(im1,jm1)) |
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243 | ENDIF |
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244 | |
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245 | IF (gradient_ij1 /= 0. .AND. gradient_ij2 /= 0.) THEN |
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246 | gradient_ij(i,j) = dj * (gradient_ij1 - gradient_ij2) |
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247 | ENDIF |
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248 | ENDIF |
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249 | |
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250 | ENDDO |
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251 | ENDDO |
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252 | ! |
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253 | END SUBROUTINE gradient_bicubic |
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