C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/eesupp/inc/CPP_EEOPTIONS.h,v 1.18 2001/09/21 03:54:35 cnh Exp $
C $Name:  $

  These lines are here to deliberately cause a compile-time error.
  If you see these lines in your .F files or the compiler shows them
  as an error then it means you have not placed your configuration
  files in the appropriate place. 
  You need to place you own copy of CPP_EEOPTIONS.h in the include
  path for the model.

CBOP
C     !ROUTINE: CPP_EEOPTIONS.h
C     !INTERFACE:
C     include "CPP_EEOPTIONS.h"
C
C     !DESCRIPTION:
C     *==========================================================*
C     | CPP_EEOPTIONS.h                                          |
C     *==========================================================*
C     | C preprocessor "execution environment" supporting        |
C     | flags. Use this file to set flags controlling the        |
C     | execution environment in which a model runs - as opposed |
C     | to the dynamical problem the model solves.               |
C     | Note: Many options are implemented with both compile time|
C     |       and run-time switches. This allows options to be   |
C     |       removed altogether, made optional at run-time or   |
C     |       to be permanently enabled. This convention helps   |
C     |       with the data-dependence analysis performed by the |
C     |       adjoint model compiler. This data dependency       |
C     |       analysis can be upset by runtime switches that it  |
C     |       is unable to recoginise as being fixed for the     |
C     |       duration of an integration.                        |
C     |       A reasonable way to use these flags is to          |
C     |       set all options as selectable at runtime but then  |
C     |       once an experimental configuration has been        |
C     |       identified, rebuild the code with the appropriate  |
C     |       options set at compile time.                       |
C     *==========================================================*
CEOP

#ifndef _CPP_EEOPTIONS_H_
#define _CPP_EEOPTIONS_H_

C     In general the following convention applies:
C     ALLOW  - indicates an feature will be included but it may
C     CAN      have a run-time flag to allow it to be switched
C              on and off.
C              If ALLOW or CAN directives are "undef'd" this generally
C              means that the feature will not be available i.e. it
C              will not be included in the compiled code and so no
C              run-time option to use the feature will be available.
C
C     ALWAYS - indicates the choice will be fixed at compile time
C              so no run-time option will be present

C     Flag used to indicate whether Fortran formatted write
C     and read are threadsafe. On SGI the routines can be thread
C     safe, on Sun it is not possible - if you are unsure then
C     undef this option.
#undef  FMTFTN_IO_THREADSAFE

C--   Control MPI based parallel processing
#undef  ALLOW_USE_MPI
#undef  ALWAYS_USE_MPI
 
C--   Control use of communication that might overlap computation.
C     Under MPI selects/deselects "non-blocking" sends and receives.
#define ALLOW_ASYNC_COMMUNICATION
#undef  ALLOW_ASYNC_COMMUNICATION
#undef  ALWAYS_USE_ASYNC_COMMUNICATION
C--   Control use of communication that is atomic to computation.
C     Under MPI selects/deselects "blocking" sends and receives.
#define ALLOW_SYNC_COMMUNICATION
#undef  ALWAYS_USE_SYNC_COMMUNICATION

C--   Control use of JAM routines for Artic network
C     These invoke optimized versions of "exchange" and "sum" that
C     utilize the programmable aspect of Artic cards.
#undef  LETS_MAKE_JAM
#undef  JAM_WITH_TWO_PROCS_PER_NODE

C--   Control storage of floating point operands
C     On many systems it improves performance only to use
C     8-byte precision for time stepped variables.
C     Constant in time terms ( geometric factors etc.. )
C     can use 4-byte precision, reducing memory utilisation and
C     boosting performance because of a smaller working
C     set size. However, on vector CRAY systems this degrades
C     performance.
#define REAL4_IS_SLOW
 
C--   Control use of "double" precision constants.
C     Use D0 where it means REAL*8 but not where it means REAL*16
#define D0 d0

C--   Control XY periodicity in processor to grid mappings
C     Note: Model code does not need to know whether a domain is 
C           periodic because it has overlap regions for every box.
C           Model assume that these values have been
C           filled in some way.
#undef  ALWAYS_PREVENT_X_PERIODICITY
#undef  ALWAYS_PREVENT_Y_PERIODICITY
#define CAN_PREVENT_X_PERIODICITY
#define CAN_PREVENT_Y_PERIODICITY

#endif /* _CPP_EEOPTIONS_H_ */

#include "CPP_EEMACROS.h"