To: J3                                                             07-163r1
From: John Reid
Subject: STOP and ALL STOP example
Date: 2007 February 15
References: 07-007, 07-155

Edits to J3/07/07

[17:13+] At the end of 2.3.6 Execution sequence, add "An example
illustrating normal and error termination of execution is contained in
C.0a."

[523:3+] Add the start of Annex C add

C.0a Clause 2 notes

C.0a.1 Normal and error termination of exection.

This code fragment illustrates the use of STOP and ALL STOP in a
climate model that uses two teams, one for the ocean and one for the
atmosphere.

If something goes badly wrong in the atmosphere calculation, the whole
model is invalid and a restart is impossible, so all images stop as
soon as possible without trying to preserve any data.

If something goes slightly wrong with the atmosphere calculation, the
images in the atmosphere team write their data to files and stop, but
their data remain available to the ocean images which complete
execution of the OCEAN subroutine. On return from the computation
routines, if something went slightly wrong with the atmosphere
calculation, the ocean images write data to files and stop, ready for
a restart in a later run.


   USE,INTRINSIC :: ISO_FORTRAN_ENV
   TYPE(IMAGE_TEAM) :: OCEAN_TEAM, ATMOSPHERE_TEAM
   INTEGER :: I, SYNC_STAT
   :
! Form two teams
   CALL FORM_TEAM (OCEAN_TEAM,[I,I=1,NUM_IMAGES()/2])
   CALL FORM_TEAM (ATMOSPHERE_TEAM,[I,I=1+NUM_IMAGES()/2,NUM_IMAGES()])
   :
! Perform independent calculations
   IF (THIS_IMAGE() > NUM_IMAGES()/2) THEN
      CALL ATMOSPHERE (ATMOSPHERE_TEAM)
   ELSE
      CALL OCEAN (OCEAN_TEAM)
   END IF
! Wait for both teams to finish
   SYNC ALL (STAT=SYNC_STAT)
   IF (SYNC_STAT == SYNC_STOPPED_IMAGE) THEN
       : ! preserve data on file
      STOP
   END IF
   CALL EXCHANGE_DATA ! Exchange data between teams
   :
CONTAINS
   SUBROUTINE ATMOSPHERE (TEAM)
      TYPE(IMAGE_TEAM) :: TEAM
      : ! Perform atmosphere calculation.
      IF (...) THEN ! something has gone slightly wrong
         : ! preserve data on file
         STOP
      END IF
   :
      IF (...) ALL STOP  ! something has gone very badly wrong
      :
      SYNC TEAM (TEAM, STAT=SYNC_STAT))
      IF (SYNC_STAT == SYNC_STOPPED_IMAGE) THEN
         : ! remaining atmosphere images preserve data in a file
         STOP
      END IF
   END SUBROUTINE ATMOSPHERE