1 | ! $Id: regr3_lint_m.F90 3065 2017-11-10 13:25:09Z jyg $ |
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2 | module regr3_lint_m |
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3 | |
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4 | ! Author: Lionel GUEZ |
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5 | |
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6 | implicit none |
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7 | |
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8 | interface regr3_lint |
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9 | ! Each procedure regrids by linear interpolation. |
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10 | ! The regridding operation is done on the third dimension of the |
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11 | ! input array. |
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12 | ! The difference betwwen the procedures is the rank of the first argument. |
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13 | module procedure regr33_lint, regr34_lint |
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14 | end interface |
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15 | |
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16 | private |
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17 | public regr3_lint |
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18 | |
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19 | contains |
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20 | |
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21 | function regr33_lint(vs, xs, xt) result(vt) |
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22 | |
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23 | ! "vs" has rank 3. |
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24 | |
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25 | use assert_eq_m, only: assert_eq |
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26 | use interpolation, only: hunt |
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27 | |
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28 | real, intent(in):: vs(:, :, :) |
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29 | ! (values of the function at source points "xs") |
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30 | |
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31 | real, intent(in):: xs(:) |
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32 | ! (abscissas of points in source grid, in strictly monotonic order) |
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33 | |
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34 | real, intent(in):: xt(:) |
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35 | ! (abscissas of points in target grid) |
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36 | |
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37 | real vt(size(vs, 1), size(vs, 2), size(xt)) |
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38 | ! (values of the function on the target grid) |
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39 | |
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40 | ! Variables local to the procedure: |
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41 | integer is, it, ns |
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42 | integer is_b ! "is" bound between 1 and "ns - 1" |
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43 | |
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44 | !-------------------------------------- |
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45 | |
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46 | ns = assert_eq(size(vs, 3), size(xs), "regr33_lint ns") |
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47 | |
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48 | is = -1 ! go immediately to bisection on first call to "hunt" |
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49 | |
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50 | do it = 1, size(xt) |
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51 | call hunt(xs, xt(it), is) |
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52 | is_b = min(max(is, 1), ns - 1) |
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53 | vt(:, :, it) = ((xs(is_b+1) - xt(it)) * vs(:, :, is_b) & |
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54 | + (xt(it) - xs(is_b)) * vs(:, :, is_b+1)) / (xs(is_b+1) - xs(is_b)) |
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55 | end do |
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56 | |
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57 | end function regr33_lint |
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58 | |
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59 | !********************************************************* |
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60 | |
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61 | function regr34_lint(vs, xs, xt) result(vt) |
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62 | |
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63 | ! "vs" has rank 4. |
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64 | |
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65 | use assert_eq_m, only: assert_eq |
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66 | use interpolation, only: hunt |
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67 | |
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68 | real, intent(in):: vs(:, :, :, :) |
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69 | ! (values of the function at source points "xs") |
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70 | |
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71 | real, intent(in):: xs(:) |
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72 | ! (abscissas of points in source grid, in strictly monotonic order) |
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73 | |
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74 | real, intent(in):: xt(:) |
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75 | ! (abscissas of points in target grid) |
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76 | |
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77 | real vt(size(vs, 1), size(vs, 2), size(xt), size(vs, 4)) |
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78 | ! (values of the function on the target grid) |
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79 | |
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80 | ! Variables local to the procedure: |
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81 | integer is, it, ns |
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82 | integer is_b ! "is" bound between 1 and "ns - 1" |
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83 | |
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84 | !-------------------------------------- |
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85 | |
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86 | ns = assert_eq(size(vs, 3), size(xs), "regr34_lint ns") |
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87 | |
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88 | is = -1 ! go immediately to bisection on first call to "hunt" |
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89 | |
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90 | do it = 1, size(xt) |
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91 | call hunt(xs, xt(it), is) |
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92 | is_b = min(max(is, 1), ns - 1) |
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93 | vt(:, :, it, :) = ((xs(is_b+1) - xt(it)) * vs(:, :, is_b, :) & |
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94 | + (xt(it) - xs(is_b)) * vs(:, :, is_b+1, :)) & |
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95 | / (xs(is_b+1) - xs(is_b)) |
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96 | end do |
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97 | |
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98 | end function regr34_lint |
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99 | |
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100 | end module regr3_lint_m |
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