trunk/dyn3d/invert_zoom_x.f

module invert_zoom_x_m

  implicit none

  INTEGER, PARAMETER:: nmax = 30000

contains

  subroutine invert_zoom_x(xf, xtild, G, xlon, xprim, xuv)

    use coefpoly_m, only: coefpoly
    USE dimens_m, ONLY: iim
    use dynetat0_m, only: clon
    use nr_util, only: pi_d, twopi_d
    use numer_rec_95, only: hunt

    DOUBLE PRECISION, intent(in):: Xf(0:), xtild(0:), G(0:) ! (0:nmax)

    real, intent(out):: xlon(:), xprim(:) ! (iim)

    DOUBLE PRECISION, intent(in):: xuv
    ! between - 0.25 and 0.5
    ! 0. si calcul aux points scalaires 
    ! 0.5 si calcul aux points U

    ! Local:
    DOUBLE PRECISION Y, abs_y, a0, a1, a2, a3
    integer i, it, iter
    real, parameter:: my_eps = 1e-6

    real xo1, Xf1
    real xvrai(iim), Gvrai(iim) 
    ! intermediary variables because xlon and xprim are simple precision

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

    it = 0 ! initial guess

    DO i = 1, iim
       Y = - pi_d + (i + xuv - 0.75d0) * twopi_d / iim
       ! - pi <= y < pi
       abs_y = abs(y)

       call hunt(xf, abs_y, it, my_lbound = 0)
       ! {0 <= it <= nmax - 1}

       ! Calcul de xvrai(i) et Gvrai(i)

       CALL coefpoly(Xf(it), Xf(it + 1), G(it), G(it + 1), xtild(it), &
            xtild(it + 1), a0, a1, a2, a3)
       xvrai(i) = xtild(it)
       Xf1 = Xf(it)
       Gvrai(i) = G(it)
       xo1 = xvrai(i)
       iter = 1

       do
          xvrai(i) = xvrai(i) - (Xf1 - abs_y) / Gvrai(i)
          IF (ABS(xvrai(i) - xo1) <= my_eps .or. iter == 300) exit
          xo1 = xvrai(i)
          Xf1 = a0 + xvrai(i) * (a1 + xvrai(i) * (a2 + xvrai(i) * a3))
          Gvrai(i) = a1 + xvrai(i) * (2d0 * a2 + xvrai(i) * 3d0 * a3)
       end DO

       if (ABS(xvrai(i) - xo1) > my_eps) then
          ! iter == 300
          print *, 'Pas de solution.'
          print *, i, abs_y
          STOP 1
       end if

       if (y < 0d0) xvrai(i) = - xvrai(i)
    end DO

    DO i = 1, iim -1
       IF (xvrai(i + 1) < xvrai(i)) THEN
          print *, 'xvrai(', i + 1, ') < xvrai(', i, ')'
          STOP 1
       END IF
    END DO

    xlon = xvrai + clon
    xprim = twopi_d / (iim * Gvrai)

  end subroutine invert_zoom_x

end module invert_zoom_x_m
1	guez	131	module invert_zoom_x_m
2	guez	121
3			implicit none
4
5			INTEGER, PARAMETER:: nmax = 30000
6
7			contains
8
9	guez	148	subroutine invert_zoom_x(xf, xtild, G, xlon, xprim, xuv)
10	guez	121
11			use coefpoly_m, only: coefpoly
12			USE dimens_m, ONLY: iim
13	guez	139	use dynetat0_m, only: clon
14	guez	124	use nr_util, only: pi_d, twopi_d
15	guez	145	use numer_rec_95, only: hunt
16	guez	121
17	guez	146	DOUBLE PRECISION, intent(in):: Xf(0:), xtild(0:), G(0:) ! (0:nmax)
18
19	guez	148	real, intent(out):: xlon(:), xprim(:) ! (iim)
20	guez	121
21			DOUBLE PRECISION, intent(in):: xuv
22	guez	145	! between - 0.25 and 0.5
23	guez	121	! 0. si calcul aux points scalaires
24	guez	145	! 0.5 si calcul aux points U
25	guez	121
26			! Local:
27	guez	148	DOUBLE PRECISION Y, abs_y, a0, a1, a2, a3
28	guez	126	integer i, it, iter
29	guez	148	real, parameter:: my_eps = 1e-6
30	guez	121
31	guez	148	real xo1, Xf1
32			real xvrai(iim), Gvrai(iim)
33			! intermediary variables because xlon and xprim are simple precision
34	guez	126
35	guez	121	!------------------------------------------------------------------
36
37	guez	145	it = 0 ! initial guess
38
39	guez	126	DO i = 1, iim
40	guez	148	Y = - pi_d + (i + xuv - 0.75d0) * twopi_d / iim
41			! - pi <= y < pi
42			abs_y = abs(y)
43	guez	121
44	guez	148	call hunt(xf, abs_y, it, my_lbound = 0)
45	guez	146	! {0 <= it <= nmax - 1}
46	guez	121
47	guez	148	! Calcul de xvrai(i) et Gvrai(i)
48	guez	121
49	guez	146	CALL coefpoly(Xf(it), Xf(it + 1), G(it), G(it + 1), xtild(it), &
50			xtild(it + 1), a0, a1, a2, a3)
51	guez	145	xvrai(i) = xtild(it)
52	guez	121	Xf1 = Xf(it)
53	guez	148	Gvrai(i) = G(it)
54	guez	126	xo1 = xvrai(i)
55	guez	121	iter = 1
56
57			do
58	guez	148	xvrai(i) = xvrai(i) - (Xf1 - abs_y) / Gvrai(i)
59	guez	126	IF (ABS(xvrai(i) - xo1) <= my_eps .or. iter == 300) exit
60			xo1 = xvrai(i)
61			Xf1 = a0 + xvrai(i) * (a1 + xvrai(i) * (a2 + xvrai(i) * a3))
62	guez	148	Gvrai(i) = a1 + xvrai(i) * (2d0 * a2 + xvrai(i) * 3d0 * a3)
63	guez	121	end DO
64
65	guez	126	if (ABS(xvrai(i) - xo1) > my_eps) then
66	guez	121	! iter == 300
67			print *, 'Pas de solution.'
68	guez	148	print *, i, abs_y
69	guez	121	STOP 1
70			end if
71
72	guez	148	if (y < 0d0) xvrai(i) = - xvrai(i)
73	guez	121	end DO
74
75			DO i = 1, iim -1
76			IF (xvrai(i + 1) < xvrai(i)) THEN
77	guez	124	print *, 'xvrai(', i + 1, ') < xvrai(', i, ')'
78	guez	121	STOP 1
79			END IF
80			END DO
81
82	guez	127	xlon = xvrai + clon
83	guez	148	xprim = twopi_d / (iim * Gvrai)
84	guez	121
85	guez	131	end subroutine invert_zoom_x
86	guez	121
87	guez	131	end module invert_zoom_x_m