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C $Header: /u/gcmpack/MITgcm/eesupp/inc/CPP_EEOPTIONS.h,v 1.32 2009/05/25 04:33:15 heimbach Exp $ |
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C $Name: $ |
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CBOP |
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C !ROUTINE: CPP_EEOPTIONS.h |
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C !INTERFACE: |
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C include "CPP_EEOPTIONS.h" |
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C |
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C !DESCRIPTION: |
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C *==========================================================* |
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C | CPP\_EEOPTIONS.h | |
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C *==========================================================* |
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C | C preprocessor "execution environment" supporting | |
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C | flags. Use this file to set flags controlling the | |
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C | execution environment in which a model runs - as opposed | |
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C | to the dynamical problem the model solves. | |
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C | Note: Many options are implemented with both compile time| |
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C | and run-time switches. This allows options to be | |
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C | removed altogether, made optional at run-time or | |
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C | to be permanently enabled. This convention helps | |
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C | with the data-dependence analysis performed by the | |
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C | adjoint model compiler. This data dependency | |
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C | analysis can be upset by runtime switches that it | |
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C | is unable to recoginise as being fixed for the | |
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C | duration of an integration. | |
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C | A reasonable way to use these flags is to | |
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C | set all options as selectable at runtime but then | |
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C | once an experimental configuration has been | |
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C | identified, rebuild the code with the appropriate | |
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C | options set at compile time. | |
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C *==========================================================* |
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CEOP |
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#ifndef _CPP_EEOPTIONS_H_ |
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#define _CPP_EEOPTIONS_H_ |
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|
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C In general the following convention applies: |
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C ALLOW - indicates an feature will be included but it may |
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C CAN have a run-time flag to allow it to be switched |
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C on and off. |
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C If ALLOW or CAN directives are "undef'd" this generally |
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C means that the feature will not be available i.e. it |
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C will not be included in the compiled code and so no |
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C run-time option to use the feature will be available. |
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C |
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C ALWAYS - indicates the choice will be fixed at compile time |
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C so no run-time option will be present |
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|
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C=== Macro related options === |
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C-- Control storage of floating point operands |
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C On many systems it improves performance only to use |
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C 8-byte precision for time stepped variables. |
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C Constant in time terms ( geometric factors etc.. ) |
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C can use 4-byte precision, reducing memory utilisation and |
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C boosting performance because of a smaller working set size. |
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C However, on vector CRAY systems this degrades performance. |
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C Enable to switch REAL4_IS_SLOW from genmake2 (with LET_RS_BE_REAL4): |
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#ifdef LET_RS_BE_REAL4 |
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#undef REAL4_IS_SLOW |
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#else /* LET_RS_BE_REAL4 */ |
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#define REAL4_IS_SLOW |
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#endif /* LET_RS_BE_REAL4 */ |
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|
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C-- Control use of "double" precision constants. |
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C Use D0 where it means REAL*8 but not where it means REAL*16 |
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#define D0 d0 |
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|
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C=== IO related options === |
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C-- Flag used to indicate whether Fortran formatted write |
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C and read are threadsafe. On SGI the routines can be thread |
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C safe, on Sun it is not possible - if you are unsure then |
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C undef this option. |
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#undef FMTFTN_IO_THREAD_SAFE |
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|
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C-- Flag used to indicate whether Binary write to Local file (i.e., |
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C a different file for each tile) and read are thread-safe. |
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#undef LOCBIN_IO_THREAD_SAFE |
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|
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C-- Flag to turn off the writing of error message to ioUnit zero |
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#undef DISABLE_WRITE_TO_UNIT_ZERO |
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|
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C-- Alternative formulation of BYTESWAP, faster than |
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C compiler flag -byteswapio on the Altix. |
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#undef FAST_BYTESWAP |
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|
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C=== MPI, EXCH and GLOBAL_SUM related options === |
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C-- Flag turns off MPI_SEND ready_to_receive polling in the |
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C gather_* subroutines to speed up integrations. |
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#undef DISABLE_MPI_READY_TO_RECEIVE |
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|
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C-- Control use of communication that might overlap computation. |
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C Under MPI selects/deselects "non-blocking" sends and receives. |
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#define ALLOW_ASYNC_COMMUNICATION |
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#undef ALLOW_ASYNC_COMMUNICATION |
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#undef ALWAYS_USE_ASYNC_COMMUNICATION |
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C-- Control use of communication that is atomic to computation. |
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C Under MPI selects/deselects "blocking" sends and receives. |
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#define ALLOW_SYNC_COMMUNICATION |
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#undef ALWAYS_USE_SYNC_COMMUNICATION |
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|
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C-- Control XY periodicity in processor to grid mappings |
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C Note: Model code does not need to know whether a domain is |
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C periodic because it has overlap regions for every box. |
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C Model assume that these values have been |
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C filled in some way. |
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#undef ALWAYS_PREVENT_X_PERIODICITY |
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#undef ALWAYS_PREVENT_Y_PERIODICITY |
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#define CAN_PREVENT_X_PERIODICITY |
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#define CAN_PREVENT_Y_PERIODICITY |
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|
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C-- Alternative way of doing global sum without MPI allreduce call |
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C but instead, explicit MPI send & recv calls. |
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#define GLOBAL_SUM_SEND_RECV |
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|
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C-- Alternative way of doing global sum on a single CPU |
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C to eliminate tiling-dependent roundoff errors. |
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C Note: This is slow. |
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#undef CG2D_SINGLECPU_SUM |
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|
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C=== Other options (to add/remove pieces of code) === |
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C-- Flag to turn on checking for errors from all threads and procs |
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C (calling S/R STOP_IF_ERROR) before stopping. |
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#define USE_ERROR_STOP |
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|
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C-- Control use of communication with other component: |
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C allow to import and export from/to Coupler interface. |
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#undef COMPONENT_MODULE |
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|
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#endif /* _CPP_EEOPTIONS_H_ */ |
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|
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#include "CPP_EEMACROS.h" |
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