trunk/libf/regr3_lint.f90

module regr3_lint_m

  ! Author: Lionel GUEZ

  implicit none

  interface regr3_lint
     ! Each procedure regrids by linear interpolation.
     ! The regridding operation is done on the third dimension of the
     ! input array.
     ! The difference betwwen the procedures is the rank of the first argument.
     module procedure regr33_lint, regr34_lint
  end interface

  private
  public regr3_lint

contains

  function regr33_lint(vs, xs, xt) result(vt)

    ! "vs" has rank 3.

    use nr_util, only: assert_eq
    use numer_rec, only: hunt

    real, intent(in):: vs(:, :, :)
    ! (values of the function at source points "xs")

    real, intent(in):: xs(:)
    ! (abscissas of points in source grid, in strictly monotonic order)

    real, intent(in):: xt(:)
    ! (abscissas of points in target grid)

    real vt(size(vs, 1), size(vs, 2), size(xt))
    ! (values of the function on the target grid)

    ! Variables local to the procedure:
    integer is, it, ns
    integer is_b ! "is" bound between 1 and "ns - 1"

    !--------------------------------------

    ns = assert_eq(size(vs, 3), size(xs), "regr33_lint ns")

    is = -1 ! go immediately to bisection on first call to "hunt"

    do it = 1, size(xt)
       call hunt(xs, xt(it), is)
       is_b = min(max(is, 1), ns - 1)
       vt(:, :, it) = ((xs(is_b+1) - xt(it)) * vs(:, :, is_b) &
            + (xt(it) - xs(is_b)) * vs(:, :, is_b+1)) / (xs(is_b+1) - xs(is_b))
    end do

  end function regr33_lint

  !*********************************************************

  function regr34_lint(vs, xs, xt) result(vt)

    ! "vs" has rank 4.

    use nr_util, only: assert_eq
    use numer_rec, only: hunt

    real, intent(in):: vs(:, :, :, :)
    ! (values of the function at source points "xs")

    real, intent(in):: xs(:)
    ! (abscissas of points in source grid, in strictly monotonic order)

    real, intent(in):: xt(:)
    ! (abscissas of points in target grid)

    real vt(size(vs, 1), size(vs, 2), size(xt), size(vs, 4))
    ! (values of the function on the target grid)

    ! Variables local to the procedure:
    integer is, it, ns
    integer is_b ! "is" bound between 1 and "ns - 1"

    !--------------------------------------

    ns = assert_eq(size(vs, 3), size(xs), "regr34_lint ns")

    is = -1 ! go immediately to bisection on first call to "hunt"

    do it = 1, size(xt)
       call hunt(xs, xt(it), is)
       is_b = min(max(is, 1), ns - 1)
       vt(:, :, it, :) = ((xs(is_b+1) - xt(it)) * vs(:, :, is_b, :) &
            + (xt(it) - xs(is_b)) * vs(:, :, is_b+1, :)) &
            / (xs(is_b+1) - xs(is_b))
    end do

  end function regr34_lint

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