trunk/dyn3d/invert_zoom_x.f

module invert_zoom_x_m

  implicit none

  INTEGER, PARAMETER:: nmax = 30000
  DOUBLE PRECISION abs_y

  private abs_y, funcd

contains

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

    use coefpoly_m, only: coefpoly, a1, a2, a3
    USE dimens_m, ONLY: iim
    use dynetat0_m, only: clon
    use nr_util, only: pi_d, twopi_d
    use numer_rec_95, only: hunt, rtsafe

    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
    integer i, it

    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))
       xvrai(i) = rtsafe(funcd, real(xtild(it)), real(xtild(it + 1)), &
            xacc = 1e-6)
       Gvrai(i) = a1 + xvrai(i) * (2d0 * a2 + xvrai(i) * 3d0 * a3)
       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

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

  SUBROUTINE funcd(x, fval, fderiv)

    use coefpoly_m, only: a0, a1, a2, a3

    REAL, INTENT(IN):: x
    REAL, INTENT(OUT):: fval, fderiv

    fval = a0 + x * (a1 + x * (a2 + x * a3)) - abs_y
    fderiv = a1 + x * (2. * a2 + x * 3. * a3)

  END SUBROUTINE funcd

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	guez	149	DOUBLE PRECISION abs_y
7	guez	121
8	guez	149	private abs_y, funcd
9
10	guez	121	contains
11
12	guez	148	subroutine invert_zoom_x(xf, xtild, G, xlon, xprim, xuv)
13	guez	121
14	guez	149	use coefpoly_m, only: coefpoly, a1, a2, a3
15	guez	121	USE dimens_m, ONLY: iim
16	guez	139	use dynetat0_m, only: clon
17	guez	124	use nr_util, only: pi_d, twopi_d
18	guez	149	use numer_rec_95, only: hunt, rtsafe
19	guez	121
20	guez	146	DOUBLE PRECISION, intent(in):: Xf(0:), xtild(0:), G(0:) ! (0:nmax)
21
22	guez	148	real, intent(out):: xlon(:), xprim(:) ! (iim)
23	guez	121
24			DOUBLE PRECISION, intent(in):: xuv
25	guez	145	! between - 0.25 and 0.5
26	guez	121	! 0. si calcul aux points scalaires
27	guez	145	! 0.5 si calcul aux points U
28	guez	121
29			! Local:
30	guez	149	DOUBLE PRECISION Y
31			integer i, it
32	guez	121
33	guez	148	real xvrai(iim), Gvrai(iim)
34			! intermediary variables because xlon and xprim are simple precision
35	guez	126
36	guez	121	!------------------------------------------------------------------
37
38	guez	145	it = 0 ! initial guess
39
40	guez	126	DO i = 1, iim
41	guez	148	Y = - pi_d + (i + xuv - 0.75d0) * twopi_d / iim
42			! - pi <= y < pi
43			abs_y = abs(y)
44	guez	121
45	guez	148	call hunt(xf, abs_y, it, my_lbound = 0)
46	guez	146	! {0 <= it <= nmax - 1}
47	guez	121
48	guez	148	! Calcul de xvrai(i) et Gvrai(i)
49	guez	146	CALL coefpoly(Xf(it), Xf(it + 1), G(it), G(it + 1), xtild(it), &
50	guez	149	xtild(it + 1))
51			xvrai(i) = rtsafe(funcd, real(xtild(it)), real(xtild(it + 1)), &
52			xacc = 1e-6)
53			Gvrai(i) = a1 + xvrai(i) * (2d0 * a2 + xvrai(i) * 3d0 * a3)
54	guez	148	if (y < 0d0) xvrai(i) = - xvrai(i)
55	guez	121	end DO
56
57			DO i = 1, iim -1
58			IF (xvrai(i + 1) < xvrai(i)) THEN
59	guez	124	print *, 'xvrai(', i + 1, ') < xvrai(', i, ')'
60	guez	121	STOP 1
61			END IF
62			END DO
63
64	guez	127	xlon = xvrai + clon
65	guez	148	xprim = twopi_d / (iim * Gvrai)
66	guez	121
67	guez	131	end subroutine invert_zoom_x
68	guez	121
69	guez	149	!**********************************************************************
70
71			SUBROUTINE funcd(x, fval, fderiv)
72
73			use coefpoly_m, only: a0, a1, a2, a3
74
75			REAL, INTENT(IN):: x
76			REAL, INTENT(OUT):: fval, fderiv
77
78			fval = a0 + x * (a1 + x * (a2 + x * a3)) - abs_y
79			fderiv = a1 + x * (2. * a2 + x * 3. * a3)
80
81			END SUBROUTINE funcd
82
83	guez	131	end module invert_zoom_x_m