--- trunk/dyn3d/fxhyp_loop_ik.f	2015/02/05 12:41:08	123
+++ trunk/Sources/dyn3d/invert_zoom_x.f	2015/06/18 13:49:26	150
@@ -1,167 +1,82 @@
-module fxhyp_loop_ik_m
+module invert_zoom_x_m
 
   implicit none
 
   INTEGER, PARAMETER:: nmax = 30000
+  DOUBLE PRECISION abs_y
+
+  private abs_y, funcd
 
 contains
 
-  subroutine fxhyp_loop_ik(ik, decalx, xf, xtild, Xprimt, xzoom, xlon, &
-       xprimm, xuv)
+  subroutine invert_zoom_x(xf, xtild, G, xlon, xprim, xuv)
 
-    use coefpoly_m, only: coefpoly
+    use coefpoly_m, only: coefpoly, a1, a2, a3
     USE dimens_m, ONLY: iim
-    use nr_util, only: pi_d, twopi_d, twopi
-    use serre, only: grossismx
+    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)
 
-    INTEGER, intent(in):: ik
-    DOUBLE PRECISION, intent(in):: decalx
-    DOUBLE PRECISION, intent(in):: Xf(0:), xtild(0:), Xprimt(0:) ! (0:2 * nmax)
-    DOUBLE PRECISION, intent(in):: xzoom
-    real, intent(out):: xlon(:), xprimm(:) ! (iim + 1)
+    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 
+    ! 0.5 si calcul aux points U
 
     ! Local:
+    DOUBLE PRECISION Y
+    integer i, it
 
-    DOUBLE PRECISION xo1, Xfi, xi, a0, a1, a2, a3, Xf1, Xprimin
-    integer ii1, ii2, i, it, iter, idif, ii
-    DOUBLE PRECISION, parameter:: my_eps = 1e-6
-    DOUBLE PRECISION xxprim(iim + 1), xvrai(iim + 1)
-    INTEGER:: is2 = 0
+    DOUBLE PRECISION xvrai(iim), Gvrai(iim) 
+    ! intermediary variables because xlon and xprim are simple precision
 
     !------------------------------------------------------------------
 
-    IF (ik == 1 .and. grossismx == 1.) THEN
-       ii1 = 2 
-       ii2 = iim + 1
-    else
-       ii1=1
-       ii2=iim
-    END IF
-
-    DO i = ii1, ii2
-       Xfi = - pi_d + (i + xuv - decalx) * twopi_d / iim
-
-       it = 2 * nmax
-       do while (xfi < xf(it) .and. it >= 1)
-          it = it - 1
-       end do
-
-       ! Calcul de Xf(xi) 
-
-       xi = xtild(it)
-
-       IF (it == 2 * nmax) THEN
-          it = 2 * nmax -1
-       END IF
-
-       CALL coefpoly(Xf(it), Xf(it + 1), Xprimt(it), Xprimt(it + 1), &
-            xtild(it), xtild(it + 1), a0, a1, a2, a3)
-       Xf1 = Xf(it)
-       Xprimin = a1 + xi * (2d0 * a2 + xi * 3d0 * a3)
-       xo1 = xi
-       iter = 1
-
-       do
-          xi = xi - (Xf1 - Xfi) / Xprimin
-          IF (ABS(xi - xo1) <= my_eps .or. iter == 300) exit
-          xo1 = xi
-          Xf1 = a0 + xi * (a1 + xi * (a2 + xi * a3))
-          Xprimin = a1 + xi * (2d0 * a2 + xi * 3d0 * a3)
-       end DO
-
-       if (ABS(xi - xo1) > my_eps) then
-          ! iter == 300
-          print *, 'Pas de solution.'
-          print *, i, xfi
-          STOP 1
-       end if
-
-       xxprim(i) = twopi_d / (REAL(iim) * Xprimin)
-       xvrai(i) = xi + xzoom
-    end DO
-
-    IF (ik == 1 .and. grossismx == 1.) THEN
-       xvrai(1) = xvrai(iim + 1)-twopi_d
-       xxprim(1) = xxprim(iim + 1)
-    END IF
+    it = 0 ! initial guess
 
     DO i = 1, iim
-       xlon(i) = xvrai(i)
-       xprimm(i) = xxprim(i)
-    END DO
+       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, xtild(it), xtild(it + 1), xacc = 1d-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 *, 'rlonu(', i + 1, ') < rlonu(', i, ')'
+          print *, 'xvrai(', i + 1, ') < xvrai(', i, ')'
           STOP 1
        END IF
     END DO
 
-    IF (ik == 1 .and. (MINval(xvrai(:iim)) < - pi_d - 0.1d0 &
-         .or. MAXval(xvrai(:iim)) > pi_d + 0.1d0)) THEN
-       IF (xzoom <= 0.) THEN
-          i = 1
-
-          do while (xvrai(i) < - pi_d .and. i < iim)
-             i = i + 1
-          end do
-
-          if (xvrai(i) < - pi_d) then
-             print *, 'Xvrai plus petit que - pi !'
-             STOP 1
-          end if
-
-          is2 = i
-       ELSE
-          i = iim
-
-          do while (xvrai(i) > pi_d .and. i > 1)
-             i = i - 1
-          end do
-
-          if (xvrai(i) > pi_d) then
-             print *, 'Xvrai plus grand que pi !'
-             STOP 1
-          end if
+    xlon = xvrai + clon
+    xprim = twopi_d / (iim * Gvrai)
 
-          is2 = i
-       END IF
-    END IF
+  end subroutine invert_zoom_x
+
+  !**********************************************************************
+
+  SUBROUTINE funcd(x, fval, fderiv)
+
+    use coefpoly_m, only: a0, a1, a2, a3
 
-    if (is2 /= 0) then
-       IF (xzoom <= 0.) THEN
-          IF (is2 /= 1) THEN
-             DO ii = is2, iim
-                xlon(ii-is2 + 1) = xvrai(ii)
-                xprimm(ii-is2 + 1) = xxprim(ii)
-             END DO
-             DO ii = 1, is2 -1
-                xlon(ii + iim-is2 + 1) = xvrai(ii) + twopi_d
-                xprimm(ii + iim-is2 + 1) = xxprim(ii) 
-             END DO
-          END IF
-       else
-          idif = iim -is2
-
-          DO ii = 1, is2
-             xlon(ii + idif) = xvrai(ii)
-             xprimm(ii + idif) = xxprim(ii)
-          END DO
-
-          DO ii = 1, idif
-             xlon(ii) = xvrai(ii + is2) - twopi_d
-             xprimm(ii) = xxprim(ii + is2) 
-          END DO
-       end IF
-    end if
+    DOUBLE PRECISION, INTENT(IN):: x
+    DOUBLE PRECISION, INTENT(OUT):: fval, fderiv
 
-    xlon(iim + 1) = xlon(1) + twopi
-    xprimm(iim + 1) = xprimm(1)
+    fval = a0 + x * (a1 + x * (a2 + x * a3)) - abs_y
+    fderiv = a1 + x * (2d0 * a2 + x * 3d0 * a3)
 
-  end subroutine fxhyp_loop_ik
+  END SUBROUTINE funcd
 
-end module fxhyp_loop_ik_m
+end module invert_zoom_x_m