SUBROUTINE check_for_restart

!------------------------------------------------------------------------------!
! Current revisions:
! -----------------
! 
!
! Former revisions:
! -----------------
! $Id: check_for_restart.f90 668 2010-12-23 13:22:58Z letzel $
!
! 667 2010-12-23 12:06:00Z suehring/gryschka
! Exchange of terminate_coupled between ocean and atmosphere by PE0
!
! 622 2010-12-10 08:08:13Z raasch
! optional barriers included in order to speed up collective operations
!
! 291 2009-04-16 12:07:26Z raasch
! Coupling with independent precursor runs.
! Output of messages replaced by message handling routine
!
! 222 2009-01-12 16:04:16Z letzel
! Implementation of an MPI-1 coupling: replaced myid with target_id
! Bugfix for nonparallel execution
!
! 108 2007-08-24 15:10:38Z letzel
! modifications to terminate coupled runs
!
! RCS Log replace by Id keyword, revision history cleaned up
!
! Revision 1.11  2007/02/11 12:55:13  raasch
! Informative output to the job protocol
!
! Revision 1.1  1998/03/18 20:06:51  raasch
! Initial revision
!
!
! Description:
! ------------
! Set stop flag, if restart is neccessary because of expiring cpu-time or
! if it is forced by user
!------------------------------------------------------------------------------!

    USE pegrid
    USE control_parameters

    IMPLICIT NONE


    LOGICAL :: terminate_run_l
    REAL ::  remaining_time


!
!-- Check remaining CPU-time
    CALL local_tremain( remaining_time )

!
!-- If necessary set a flag to stop the model run
    terminate_run_l = .FALSE.
    IF ( remaining_time <= termination_time_needed  .AND. &
         write_binary(1:4) == 'true' )  THEN

       terminate_run_l = .TRUE.
    ENDIF

#if defined( __parallel )
!
!-- Make a logical OR for all processes. Stop the model run if at least
!-- one processor has reached the time limit.
    IF ( collective_wait )  CALL MPI_BARRIER( comm2d, ierr )
    CALL MPI_ALLREDUCE( terminate_run_l, terminate_run, 1, MPI_LOGICAL, &
                        MPI_LOR, comm2d, ierr )
#else
    terminate_run = terminate_run_l
#endif

!
!-- Output that job will be terminated
    IF ( terminate_run  .AND.  myid == 0 )  THEN
       WRITE( message_string, * ) 'run will be terminated because it is ', &
                       'running out of job cpu limit & ',                  &
                       'remaining time:         ', remaining_time, ' s',   &
                       'termination time needed:', termination_time_needed, ' s'
       CALL message( 'check_for_restart', 'PA0163', 0, 1, 0, 6, 0 )
    ENDIF

!
!-- In case of coupled runs inform the remote model of the termination 
!-- and its reason, provided the remote model has not already been 
!-- informed of another termination reason (terminate_coupled > 0) before, 
!-- or vice versa (terminate_coupled_remote > 0).
    IF ( terminate_run .AND. TRIM( coupling_mode ) /= 'uncoupled'  .AND. &
         terminate_coupled == 0  .AND.  terminate_coupled_remote == 0 )  THEN

       terminate_coupled = 3
#if defined( __parallel )
       IF ( myid == 0 ) THEN
          CALL MPI_SENDRECV( terminate_coupled,        1, MPI_INTEGER,          &
                             target_id, 0,                                      &
                             terminate_coupled_remote, 1, MPI_INTEGER,          &
                             target_id, 0,                                      &
                             comm_inter, status, ierr )
       ENDIF
       CALL MPI_BCAST( terminate_coupled_remote, 1, MPI_INTEGER, 0, comm2d, ierr)
#endif
    ENDIF

!
!-- Set the stop flag also, if restart is forced by user
    IF ( time_restart /= 9999999.9  .AND.  &
         time_restart < time_since_reference_point )  THEN

!
!--    Restart is not neccessary, if the end time of the run (given by
!--    the user) has been reached
       IF ( simulated_time < end_time )  THEN
          terminate_run = .TRUE.
!
!--       Increment restart time, if forced by user, otherwise set restart
!--       time to default (no user restart)
          IF ( dt_restart /= 9999999.9 )  THEN
             time_restart = time_restart + dt_restart
          ELSE
             time_restart = 9999999.9
          ENDIF

          WRITE( message_string, * ) 'run will be terminated due to user ', &
                                  'settings of',                            &
                                  '&restart_time / dt_restart',             &
                                  '&new restart time is: ', time_restart, ' s' 
          CALL message( 'check_for_restart', 'PA0164', 0, 0, 0, 6, 0 )
 
!
!--       In case of coupled runs inform the remote model of the termination 
!--       and its reason, provided the remote model has not already been 
!--       informed of another termination reason (terminate_coupled > 0) before,
!--       or vice versa (terminate_coupled_remote > 0).
          IF ( coupling_mode /= 'uncoupled' .AND. terminate_coupled == 0  &
               .AND.  terminate_coupled_remote == 0 )  THEN

             IF ( dt_restart /= 9999999.9 )  THEN
                terminate_coupled = 4
             ELSE
                terminate_coupled = 5
             ENDIF
#if defined( __parallel )
             IF ( myid == 0 ) THEN
                CALL MPI_SENDRECV( terminate_coupled,        1, MPI_INTEGER,    &
                                   target_id,  0,                               &
                                   terminate_coupled_remote, 1, MPI_INTEGER,    &
                                   target_id,  0,                               &
                                   comm_inter, status, ierr )   
             ENDIF
             CALL MPI_BCAST( terminate_coupled_remote, 1, MPI_INTEGER, 0, comm2d, ierr)  
            
#endif
          ENDIF
       ELSE
          time_restart = 9999999.9
       ENDIF
    ENDIF

!
!-- If the run is stopped, set a flag file which is necessary to initiate
!-- the start of a continuation run
    IF ( terminate_run  .AND.  myid == 0 )  THEN

       OPEN ( 90, FILE='CONTINUE_RUN', FORM='FORMATTED' )
       WRITE ( 90, '(A)' )  TRIM( run_description_header )
       CLOSE ( 90 )

    ENDIF


 END SUBROUTINE check_for_restart