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