PROGRAM palm

!------------------------------------------------------------------------------!
! Current revisions:
! -----------------
! 
!
! Former revisions:
! -----------------
! $Id: palm.f90 863 2012-03-26 14:28:17Z fricke $
!
! Version number changed from 3.8 to 3.8a.
!
! 849 2012-03-15 10:35:09Z raasch
! write_particles renamed lpm_write_restart_file
!
! 759 2011-09-15 13:58:31Z raasch
! Splitting of parallel I/O, cpu measurement for write_3d_binary and opening
! of unit 14 moved to here
!
! 495 2010-03-02 00:40:15Z raasch
! Particle data for restart runs are only written if write_binary=.T..
!
! 215 2008-11-18 09:54:31Z raasch
! Initialization of coupled runs modified for MPI-1 and moved to external
! subroutine init_coupling
!
! 197 2008-09-16 15:29:03Z raasch
! Workaround for getting information about the coupling mode
!
! 108 2007-08-24 15:10:38Z letzel
! Get coupling mode from environment variable, change location of debug output
!
! 75 2007-03-22 09:54:05Z raasch
! __vtk directives removed, write_particles is called only in case of particle
! advection switched on, open unit 9 for debug output,
! setting of palm version moved from modules to here
!
! RCS Log replace by Id keyword, revision history cleaned up
!
! Revision 1.10  2006/08/04 14:53:12  raasch
! Distibution of run description header removed, call of header moved behind
! init_3d_model
!
! Revision 1.2  2001/01/25 07:15:06  raasch
! Program name changed to PALM, module test_variables removed.
! Initialization of dvrp logging as well as exit of dvrp moved to new
! subroutines init_dvrp_logging and close_dvrp (file init_dvrp.f90)
!
! Revision 1.1  1997/07/24 11:23:35  raasch
! Initial revision
!
!
! Description:
! ------------
! Large-Eddy Simulation (LES) model for the convective boundary layer, 
! optimized for use on parallel machines (implementation realized using the
! Message Passing Interface (MPI)). The model can also be run on vector machines
! (less well optimized) and workstations. Versions for the different types of 
! machines are controlled via cpp-directives.
! Model runs are only feasible using the ksh-script mrun.
!------------------------------------------------------------------------------!


    USE arrays_3d
    USE constants
    USE control_parameters
    USE cpulog
    USE dvrp_variables
    USE grid_variables
    USE indices
    USE interfaces
    USE model_1d
    USE particle_attributes
    USE pegrid
    USE spectrum
    USE statistics

    IMPLICIT NONE

!
!-- Local variables
    CHARACTER (LEN=9) ::  time_to_string
    CHARACTER (LEN=1) ::  cdum
    INTEGER           ::  i, run_description_header_i(80)

    version = 'PALM 3.8a'

#if defined( __parallel )
!
!-- MPI initialisation. comm2d is preliminary set, because
!-- it will be defined in init_pegrid but is used before in cpu_log.
    CALL MPI_INIT( ierr )
    CALL MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr )
    CALL MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr )
    comm_palm = MPI_COMM_WORLD
    comm2d    = MPI_COMM_WORLD

!
!-- Initialize PE topology in case of coupled runs
    CALL init_coupling
#endif

!
!-- Initialize measuring of the CPU-time remaining to the run
    CALL local_tremain_ini

!
!-- Start of total CPU time measuring.
    CALL cpu_log( log_point(1), 'total', 'start' )
    CALL cpu_log( log_point(2), 'initialisation', 'start' )

!
!-- Open a file for debug output
    WRITE (myid_char,'(''_'',I4.4)')  myid
    OPEN( 9, FILE='DEBUG'//TRIM( coupling_char )//myid_char, FORM='FORMATTED' )

!
!-- Initialize dvrp logging. Also, one PE maybe split from the global
!-- communicator for doing the dvrp output. In that case, the number of
!-- PEs available for PALM is reduced by one and communicator comm_palm
!-- is changed respectively.
#if defined( __parallel )
    CALL MPI_COMM_RANK( comm_palm, myid, ierr )
!
!-- TEST OUTPUT (TO BE REMOVED)
    WRITE(9,*) '*** coupling_mode = "', TRIM( coupling_mode ), '"'
    CALL LOCAL_FLUSH( 9 )
    IF ( TRIM( coupling_mode ) /= 'uncoupled' )  THEN
       PRINT*, '*** PE', myid, ' Global target PE:', target_id, &
               TRIM( coupling_mode )
    ENDIF
#endif

    CALL init_dvrp_logging

!
!-- Read control parameters from NAMELIST files and read environment-variables
    CALL parin

!
!-- Determine processor topology and local array indices
    CALL init_pegrid

!
!-- Generate grid parameters
    CALL init_grid

!
!-- Check control parameters and deduce further quantities
    CALL check_parameters


!
!-- Initialize all necessary variables
    CALL init_3d_model

!
!-- Output of program header
    IF ( myid == 0 )  CALL header

    CALL cpu_log( log_point(2), 'initialisation', 'stop' )

!
!-- Set start time in format hh:mm:ss
    simulated_time_chr = time_to_string( simulated_time )

!
!-- If required, output of initial arrays
    IF ( do2d_at_begin )  THEN
       CALL data_output_2d( 'xy', 0 )
       CALL data_output_2d( 'xz', 0 )
       CALL data_output_2d( 'yz', 0 )
    ENDIF
    IF ( do3d_at_begin )  THEN
       CALL data_output_3d( 0 )
    ENDIF

!
!-- Integration of the model equations using timestep-scheme
    CALL time_integration

!
!-- If required, write binary data for restart runs
    IF ( write_binary(1:4) == 'true' )  THEN

       CALL cpu_log( log_point(22), 'write_3d_binary', 'start' )

       CALL check_open( 14 )

       DO  i = 0, io_blocks-1
          IF ( i == io_group )  THEN
!
!--          Write flow field data
             CALL write_3d_binary
          ENDIF
#if defined( __parallel )
          CALL MPI_BARRIER( comm2d, ierr )
#endif
       ENDDO

       CALL cpu_log( log_point(22), 'write_3d_binary', 'stop' )

!
!--    If required, write particle data
       IF ( particle_advection )  CALL lpm_write_restart_file
    ENDIF

!
!-- If required, repeat output of header including the required CPU-time
    IF ( myid == 0 )  CALL header
!
!-- If required, final user-defined actions, and
!-- last actions on the open files and close files. Unit 14 was opened
!-- in write_3d_binary but it is closed here, to allow writing on this
!-- unit in routine user_last_actions.
    CALL cpu_log( log_point(4), 'last actions', 'start' )
    DO  i = 0, io_blocks-1
       IF ( i == io_group )  THEN
          CALL user_last_actions
          IF ( write_binary(1:4) == 'true' )  CALL close_file( 14 )
       ENDIF
#if defined( __parallel )
       CALL MPI_BARRIER( comm2d, ierr )
#endif
    ENDDO
    CALL close_file( 0 )
    CALL close_dvrp
    CALL cpu_log( log_point(4), 'last actions', 'stop' )

#if defined( __mpi2 )
!
!-- Test exchange via intercommunicator in case of a MPI-2 coupling
    IF ( coupling_mode == 'atmosphere_to_ocean' )  THEN
       i = 12345 + myid
       CALL MPI_SEND( i, 1, MPI_INTEGER, myid, 11, comm_inter, ierr )
    ELSEIF ( coupling_mode == 'ocean_to_atmosphere' )  THEN
       CALL MPI_RECV( i, 1, MPI_INTEGER, myid, 11, comm_inter, status, ierr )
       PRINT*, '### myid: ', myid, '   received from atmosphere:  i = ', i
    ENDIF
#endif

!
!-- Take final CPU-time for CPU-time analysis
    CALL cpu_log( log_point(1), 'total', 'stop' )
    CALL cpu_statistics

#if defined( __parallel )
    CALL MPI_FINALIZE( ierr )
#endif

 END PROGRAM palm