C $Header: /u/gcmpack/MITgcm/verification/cpl_aim+ocn/code_ocn/CPP_EEOPTIONS.h,v 1.10 2015/11/04 17:09:20 jmc Exp $ C $Name: $ 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=== Macro related options === 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 set size. C However, on vector CRAY systems this degrades performance. C Enable to switch REAL4_IS_SLOW from genmake2 (with LET_RS_BE_REAL4): #ifdef LET_RS_BE_REAL4 #undef REAL4_IS_SLOW #else /* LET_RS_BE_REAL4 */ #define REAL4_IS_SLOW #endif /* LET_RS_BE_REAL4 */ 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=== IO related options === 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_THREAD_SAFE C-- Flag used to indicate whether Binary write to Local file (i.e., C a different file for each tile) and read are thread-safe. #undef LOCBIN_IO_THREAD_SAFE C-- Flag to turn off the writing of error message to ioUnit zero #undef DISABLE_WRITE_TO_UNIT_ZERO C-- Alternative formulation of BYTESWAP, faster than C compiler flag -byteswapio on the Altix. #undef FAST_BYTESWAP C-- Flag defined for eeboot_minimal.F, eeset_parms.F and open_copy_data_file.F C to write STDOUT, STDERR and scratch files from process 0 only. C WARNING: to use only when absolutely confident that the setup is working C since any message (error/warning/print) from any proc <> 0 will be lost. #undef SINGLE_DISK_IO C=== MPI, EXCH and GLOBAL_SUM related options === C-- Flag turns off MPI_SEND ready_to_receive polling in the C gather_* subroutines to speed up integrations. #undef DISABLE_MPI_READY_TO_RECEIVE 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 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 C-- disconnect tiles (no exchange between tiles, just fill-in edges C assuming locally periodic subdomain) #undef DISCONNECTED_TILES C-- Always cumulate tile local-sum in the same order by applying MPI allreduce C to array of tiles ; can get slower with large number of tiles (big set-up) #define GLOBAL_SUM_ORDER_TILES C-- Alternative way of doing global sum without MPI allreduce call C but instead, explicit MPI send & recv calls. Expected to be slower. #undef GLOBAL_SUM_SEND_RECV C-- Alternative way of doing global sum on a single CPU C to eliminate tiling-dependent roundoff errors. Note: This is slow. #undef CG2D_SINGLECPU_SUM C=== Other options (to add/remove pieces of code) === C-- Flag to turn on checking for errors from all threads and procs C (calling S/R STOP_IF_ERROR) before stopping. #define USE_ERROR_STOP C-- Control use of communication with other component: C allow to import and export from/to Coupler interface. #define COMPONENT_MODULE #endif /* _CPP_EEOPTIONS_H_ */ #include "CPP_EEMACROS.h"