! $Id$
module press_coefoz_m

  IMPLICIT NONE

  REAL, ALLOCATABLE, save:: plev(:)
  ! (pressure level of Mobidic input data, converted to Pa, in strictly
  ! ascending order)

  REAL, ALLOCATABLE, save:: press_in_edg(:)
  ! (edges of pressure intervals for Mobidic input data, in Pa, in strictly
  ! ascending order)

CONTAINS

  SUBROUTINE press_coefoz

    ! This procedure is called once per "gcm" run.
    ! A single thread of the root process reads the pressure levels
    ! from "coefoz_LMDZ.nc" and broadcasts them to the other processes.

    ! We assume that, in "coefoz_LMDZ.nc", the pressure levels are in hPa
    ! and in strictly ascending order.

    USE netcdf95, ONLY: nf95_open, nf95_close, nf95_gw_var, nf95_inq_varid
    USE netcdf, ONLY: nf90_nowrite

    USE lmdz_phys_mpi_data, ONLY: is_mpi_root
    USE lmdz_phys_mpi_transfert, ONLY: bcast_mpi ! broadcast

    ! Variables local to the procedure:
    INTEGER ncid, varid ! for NetCDF
    INTEGER n_plev ! number of pressure levels in the input data
    INTEGER k

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

    !$omp single
    PRINT *, "Call sequence information: press_coefoz"

    IF (is_mpi_root) THEN
       CALL nf95_open("coefoz_LMDZ.nc", nf90_nowrite, ncid)

       CALL nf95_inq_varid(ncid, "plev", varid)
       CALL nf95_gw_var(ncid, varid, plev)
       ! Convert from hPa to Pa because "paprs" and "pplay" are in Pa:
       plev = plev * 100.
       n_plev = size(plev)

       CALL nf95_close(ncid)
    end if

    CALL bcast_mpi(n_plev)
    IF (.NOT. is_mpi_root) allocate(plev(n_plev))
    CALL bcast_mpi(plev)
    
    ! Compute edges of pressure intervals:
    allocate(press_in_edg(n_plev + 1))
    IF (is_mpi_root) THEN
       press_in_edg(1) = 0.
       ! We choose edges halfway in logarithm:
       DO k = 2,n_plev
          press_in_edg(k) = SQRT(plev(k - 1) * plev(k))
       ENDDO
       press_in_edg(n_plev + 1) = huge(0.)
       ! (infinity, but any value guaranteed to be greater than the
       ! surface pressure would do)
    end if
    CALL bcast_mpi(press_in_edg)
    !$omp end single

  END SUBROUTINE  press_coefoz

END MODULE press_coefoz_m