! $Id: ropp_pp_wopt.f90 r4887 2016-05-25 15:48:28Z sti $

!****m* Modules/ropp_pp_wopt *
!
! NAME
!   ropp_pp_wopt - Interface module for the ropp_pp wave optics propagator routines.
!
! SYNOPSIS
!   USE ropp_pp_wopt
!
! DESCRIPTION
!   This module provides interfaces for the wave optics propagation
!   routines contained in the ROPP PP library.
!
! SEE ALSO
!   ropp_pp/tools/ropp_pp_wopt_tool(.f90)
!   ropp_pp/tools/ropp_pp_wopt_2D_tool(.f90)
!
! NOTES
!   See RSR 28 for details
!
! AUTHOR
!   Met Office, Exeter, UK.
!   Any comments on this software should be given via the ROM SAF
!   Helpdesk at http://www.romsaf.org
!
! COPYRIGHT
!   (c) EUMETSAT. All rights reserved.
!   For further details please refer to the file COPYRIGHT
!   which you should have received as part of this distribution.
!
!****

MODULE ropp_pp_wopt

!-------------------------------------------------------------------------------
! 1. Phase propagation
!-------------------------------------------------------------------------------

  INTERFACE ropp_pp_wopt_mps_1d
    SUBROUTINE ropp_pp_wopt_mps_1d(x, y, radius, y_apodize, kval, &
                                   zed, log_refrac, d2logndy2, U0, U)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)     :: x(:), y(:)
      REAL(wp), INTENT(IN)     :: radius, y_apodize, kval
      REAL(wp), INTENT(IN)     :: zed(:), log_refrac(:), d2logndy2(:)
      COMPLEX(wp), INTENT(IN)  :: U0(:)
      COMPLEX(wp), INTENT(OUT) :: U(SIZE(y))
    END SUBROUTINE ropp_pp_wopt_mps_1d
  END INTERFACE ropp_pp_wopt_mps_1d
  
  INTERFACE ropp_pp_wopt_mps_2d
    SUBROUTINE ropp_pp_wopt_mps_2d(x, y, radius, y_apodize, kval, dtheta, &
                                   zed, log_refrac, d2logndy2, U0, U)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)     :: x(:), y(:)
      REAL(wp), INTENT(IN)     :: radius, y_apodize, kval, dtheta
      REAL(wp), INTENT(IN)     :: zed(:,:), log_refrac(:,:), d2logndy2(:,:)
      COMPLEX(wp), INTENT(IN)  :: U0(:)
      COMPLEX(wp), INTENT(OUT) :: U(SIZE(y))
    END SUBROUTINE ropp_pp_wopt_mps_2d
  END INTERFACE ropp_pp_wopt_mps_2d


  INTERFACE
    SUBROUTINE ropp_pp_wopt_propagate(U0, k, Dy, Dx, U)
      USE typesizes, ONLY: wp => EightByteReal
      COMPLEX(wp), INTENT(IN)  :: U0(:)
      REAL(wp), INTENT(IN)     :: k
      REAL(wp), INTENT(IN)     :: Dy
      REAL(wp), INTENT(IN)     :: Dx
      COMPLEX(wp), INTENT(OUT) :: U(SIZE(U0))
    END SUBROUTINE ropp_pp_wopt_propagate
  END INTERFACE


  INTERFACE
    SUBROUTINE ropp_pp_wopt_propagate_to_leo(nsample, U0, k, ypos, Dy, x_plane, &
                                             x_leo, y_leo, s_geom, U_leo, phase_leo, amp_leo)
      USE typesizes, ONLY: wp => EightByteReal
      INTEGER, INTENT(IN)      :: nsample
      COMPLEX(wp), INTENT(IN)  :: U0(:)
      REAL(wp), INTENT(IN)     :: k
      REAL(wp), INTENT(IN)     :: Dy
      REAL(wp), INTENT(IN)     :: ypos(:)
      REAL(wp), INTENT(IN)     :: x_plane
      REAL(wp), INTENT(IN)     :: x_leo(:), y_leo(:)
      REAL(wp), INTENT(IN)     :: s_geom(:)
      COMPLEX(wp), INTENT(OUT) :: U_leo(SIZE(x_leo))
      REAL(wp), INTENT(OUT)    :: phase_leo(SIZE(x_leo)), amp_leo(SIZE(x_leo))
      END SUBROUTINE ropp_pp_wopt_propagate_to_leo
  END INTERFACE


!-------------------------------------------------------------------------------
! 2. Refractivity
!-------------------------------------------------------------------------------

  INTERFACE
    SUBROUTINE ropp_pp_wopt_ref_1d(x, y, radius, zed, logn, d2logndy2, refrac)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)  :: x
      REAL(wp), INTENT(IN)  :: y(:)
      REAL(wp), INTENT(IN)  :: radius
      REAL(wp), INTENT(IN)  :: zed(:), logn(:)
      REAL(wp), INTENT(IN)  :: d2logndy2(:)
      REAL(wp), INTENT(OUT) :: refrac(SIZE(y))
    END SUBROUTINE ropp_pp_wopt_ref_1d
  END INTERFACE
  
  INTERFACE
    SUBROUTINE ropp_pp_wopt_ref_2d(dtheta, x, y, radius, zed, logn, d2logndy2, refrac)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)  :: dtheta
      REAL(wp), INTENT(IN)  :: x
      REAL(wp), INTENT(IN)  :: y(:)
      REAL(wp), INTENT(IN)  :: radius
      REAL(wp), INTENT(IN)  :: zed(:,:), logn(:,:)
      REAL(wp), INTENT(IN)  :: d2logndy2(:,:)
      REAL(wp), INTENT(OUT) :: refrac(SIZE(y))
    END SUBROUTINE ropp_pp_wopt_ref_2d
  END INTERFACE


!-------------------------------------------------------------------------------
! 3. Phase and amplitude calculation
!-------------------------------------------------------------------------------

  INTERFACE
    SUBROUTINE ropp_pp_wopt_phase_and_amplitude(U, phase, amplitude)
      USE typesizes, ONLY: wp => EightByteReal
      COMPLEX(wp), INTENT(IN)  :: U(:)
      REAL(wp),    INTENT(OUT) :: phase(SIZE(U)), amplitude(SIZE(U))
    END SUBROUTINE ropp_pp_wopt_phase_and_amplitude
  END INTERFACE


  INTERFACE
    SUBROUTINE ropp_pp_wopt_phase_and_amplitude_leo(U, phase, amplitude)
      USE typesizes, ONLY: wp => EightByteReal
      COMPLEX(wp), INTENT(IN)  :: U(:)
      REAL(wp),    INTENT(OUT) :: phase(SIZE(U)), amplitude(SIZE(U))
    END SUBROUTINE ropp_pp_wopt_phase_and_amplitude_leo
  END INTERFACE


!-------------------------------------------------------------------------------
! 4. Fresnel integral
!-------------------------------------------------------------------------------

  INTERFACE
    SUBROUTINE ropp_pp_wopt_fresnel(x, s, c)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)  :: x(:)
      REAL(wp), INTENT(OUT) :: s(SIZE(x)), c(SIZE(x))
    END SUBROUTINE ropp_pp_wopt_fresnel
  END INTERFACE


!-------------------------------------------------------------------------------
! 5. Apodization
!-------------------------------------------------------------------------------

  INTERFACE
    SUBROUTINE ropp_pp_wopt_window(x, y, rad, ymax, U)
      USE typesizes, ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)      :: x, rad, ymax
      REAL(wp), INTENT(IN)      :: y(:)
      COMPLEX(wp),INTENT(INOUT) :: U(:)
    END SUBROUTINE ropp_pp_wopt_window
  END INTERFACE


!-------------------------------------------------------------------------------
! 6. Full Spectrum Inversion
!-------------------------------------------------------------------------------

  INTERFACE
    SUBROUTINE ropp_pp_wopt_fsi_quick(kval, theta_dot, time, s_geom, &
                                      phase_leo, amp_leo, x_leo, y_leo, &
                                      x_gps, y_gps, &
                                      impact, alpha, amp)
      USE typesizes,         ONLY: wp => EightByteReal
      REAL(wp), INTENT(IN)    :: kval               ! wave number
      REAL(wp), INTENT(IN)    :: theta_dot          ! angular velocity
      REAL(wp), INTENT(IN)    :: time(:)            ! time at LEO
      REAL(wp), INTENT(IN)    :: s_geom(:)          ! straight line GNSS-to-LEO distance
      REAL(wp), INTENT(IN)    :: x_leo(:),y_leo(:)  ! position of LEO
      REAL(wp), INTENT(IN)    :: x_gps(:),y_gps(:)  ! position of GPS
      REAL(wp), INTENT(IN)    :: phase_leo(:)       ! accumulated phase at LEO
      REAL(wp), INTENT(IN)    :: amp_leo(:)         ! amplitude at LEO
      REAL(wp), INTENT(INOUT) :: impact(:)          ! impact height
      REAL(wp), INTENT(INOUT) :: alpha(:)           ! bending angle
      REAL(wp), INTENT(INOUT) :: amp(:)             ! amplitude
    END SUBROUTINE ropp_pp_wopt_fsi_quick
  END INTERFACE


END MODULE ropp_pp_wopt