[1157] | 1 | ! $Id$ |
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| 2 | module regr1_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 regr1_lint |
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| 9 | ! Each procedure regrids by linear interpolation. |
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| 10 | ! The regridding operation is done on the first 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 regr11_lint, regr12_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 regr1_lint |
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| 18 | |
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| 19 | contains |
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| 20 | |
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| 21 | function regr11_lint(vs, xs, xt) result(vt) |
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| 22 | |
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| 23 | ! "vs" has rank 1. |
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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 !!, polint |
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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(xt)) ! values of the function on the target grid |
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| 38 | |
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| 39 | ! Variables local to the procedure: |
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| 40 | integer is, it, ns |
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| 41 | integer is_b ! "is" bound between 1 and "ns - 1" |
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| 42 | |
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| 43 | !-------------------------------------- |
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| 44 | |
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| 45 | ns = assert_eq(size(vs), size(xs), "regr11_lint ns") |
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| 46 | |
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| 47 | is = -1 ! go immediately to bisection on first call to "hunt" |
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| 48 | |
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| 49 | do it = 1, size(xt) |
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| 50 | call hunt(xs, xt(it), is) |
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| 51 | is_b = min(max(is, 1), ns - 1) |
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| 52 | !! call polint(xs(is_b:is_b+1), vs(is_b:is_b+1), xt(it), vt(it)) |
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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 regr11_lint |
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| 58 | |
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| 59 | !********************************************************* |
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| 60 | |
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| 61 | function regr12_lint(vs, xs, xt) result(vt) |
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| 62 | |
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| 63 | ! "vs" has rank 2. |
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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(xt), size(vs, 2)) ! values of the function on the target grid |
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| 78 | |
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| 79 | ! Variables local to the procedure: |
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| 80 | integer is, it, ns |
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| 81 | integer is_b ! "is" bound between 1 and "ns - 1" |
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| 82 | |
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| 83 | !-------------------------------------- |
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| 84 | |
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| 85 | ns = assert_eq(size(vs, 1), size(xs), "regr12_lint ns") |
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| 86 | |
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| 87 | is = -1 ! go immediately to bisection on first call to "hunt" |
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| 88 | |
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| 89 | do it = 1, size(xt) |
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| 90 | call hunt(xs, xt(it), is) |
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| 91 | is_b = min(max(is, 1), ns - 1) |
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| 92 | vt(it, :) = ((xs(is_b+1) - xt(it)) * vs(is_b, :) & |
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| 93 | + (xt(it) - xs(is_b)) * vs(is_b+1, :)) / (xs(is_b+1) - xs(is_b)) |
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| 94 | end do |
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| 95 | |
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| 96 | end function regr12_lint |
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| 97 | |
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| 98 | end module regr1_lint_m |
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