/[MITgcm]/MITgcm/eesupp/inc/CPP_EEOPTIONS.h
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Contents of /MITgcm/eesupp/inc/CPP_EEOPTIONS.h

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Revision 1.43 - (show annotations) (download)
Thu Sep 14 19:47:35 2017 UTC (6 years, 10 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint66o, checkpoint66n, checkpoint66m, checkpoint66l, checkpoint66k, HEAD
Changes since 1.42: +4 -1 lines
File MIME type: text/plain
- add CPP option to activate some pieces of code for coupling to GEOS AGCM
- shift commonly used IO unit for coupling to GEOS AGCM

1 C $Header: /u/gcmpack/MITgcm/eesupp/inc/CPP_EEOPTIONS.h,v 1.42 2017/08/09 15:18:49 mlosch Exp $
2 C $Name: $
3
4 CBOP
5 C !ROUTINE: CPP_EEOPTIONS.h
6 C !INTERFACE:
7 C include "CPP_EEOPTIONS.h"
8 C
9 C !DESCRIPTION:
10 C *==========================================================*
11 C | CPP\_EEOPTIONS.h |
12 C *==========================================================*
13 C | C preprocessor "execution environment" supporting |
14 C | flags. Use this file to set flags controlling the |
15 C | execution environment in which a model runs - as opposed |
16 C | to the dynamical problem the model solves. |
17 C | Note: Many options are implemented with both compile time|
18 C | and run-time switches. This allows options to be |
19 C | removed altogether, made optional at run-time or |
20 C | to be permanently enabled. This convention helps |
21 C | with the data-dependence analysis performed by the |
22 C | adjoint model compiler. This data dependency |
23 C | analysis can be upset by runtime switches that it |
24 C | is unable to recoginise as being fixed for the |
25 C | duration of an integration. |
26 C | A reasonable way to use these flags is to |
27 C | set all options as selectable at runtime but then |
28 C | once an experimental configuration has been |
29 C | identified, rebuild the code with the appropriate |
30 C | options set at compile time. |
31 C *==========================================================*
32 CEOP
33
34 #ifndef _CPP_EEOPTIONS_H_
35 #define _CPP_EEOPTIONS_H_
36
37 C In general the following convention applies:
38 C ALLOW - indicates an feature will be included but it may
39 C CAN have a run-time flag to allow it to be switched
40 C on and off.
41 C If ALLOW or CAN directives are "undef'd" this generally
42 C means that the feature will not be available i.e. it
43 C will not be included in the compiled code and so no
44 C run-time option to use the feature will be available.
45 C
46 C ALWAYS - indicates the choice will be fixed at compile time
47 C so no run-time option will be present
48
49 C=== Macro related options ===
50 C-- Control storage of floating point operands
51 C On many systems it improves performance only to use
52 C 8-byte precision for time stepped variables.
53 C Constant in time terms ( geometric factors etc.. )
54 C can use 4-byte precision, reducing memory utilisation and
55 C boosting performance because of a smaller working set size.
56 C However, on vector CRAY systems this degrades performance.
57 C Enable to switch REAL4_IS_SLOW from genmake2 (with LET_RS_BE_REAL4):
58 #ifdef LET_RS_BE_REAL4
59 #undef REAL4_IS_SLOW
60 #else /* LET_RS_BE_REAL4 */
61 #define REAL4_IS_SLOW
62 #endif /* LET_RS_BE_REAL4 */
63
64 C-- Control use of "double" precision constants.
65 C Use D0 where it means REAL*8 but not where it means REAL*16
66 #define D0 d0
67
68 C-- Enable some old macro conventions for backward compatibility
69 #undef USE_OLD_MACROS_R4R8toRSRL
70
71 C=== IO related options ===
72 C-- Flag used to indicate whether Fortran formatted write
73 C and read are threadsafe. On SGI the routines can be thread
74 C safe, on Sun it is not possible - if you are unsure then
75 C undef this option.
76 #undef FMTFTN_IO_THREAD_SAFE
77
78 C-- Flag used to indicate whether Binary write to Local file (i.e.,
79 C a different file for each tile) and read are thread-safe.
80 #undef LOCBIN_IO_THREAD_SAFE
81
82 C-- Flag to turn off the writing of error message to ioUnit zero
83 #undef DISABLE_WRITE_TO_UNIT_ZERO
84
85 C-- Alternative formulation of BYTESWAP, faster than
86 C compiler flag -byteswapio on the Altix.
87 #undef FAST_BYTESWAP
88
89 C-- Flag to turn on old default of opening scratch files with the
90 C STATUS='SCRATCH' option. This method, while perfectly FORTRAN-standard,
91 C caused filename conflicts on some multi-node/multi-processor platforms
92 C in the past and has been replace by something (hopefully) more robust.
93 #undef USE_FORTRAN_SCRATCH_FILES
94
95 C-- Flag defined for eeboot_minimal.F, eeset_parms.F and open_copy_data_file.F
96 C to write STDOUT, STDERR and scratch files from process 0 only.
97 C WARNING: to use only when absolutely confident that the setup is working
98 C since any message (error/warning/print) from any proc <> 0 will be lost.
99 #undef SINGLE_DISK_IO
100
101 C=== MPI, EXCH and GLOBAL_SUM related options ===
102 C-- Flag turns off MPI_SEND ready_to_receive polling in the
103 C gather_* subroutines to speed up integrations.
104 #undef DISABLE_MPI_READY_TO_RECEIVE
105
106 C-- Control MPI based parallel processing
107 CXXX We no longer select the use of MPI via this file (CPP_EEOPTIONS.h)
108 CXXX To use MPI, use an appropriate genmake2 options file or use
109 CXXX genmake2 -mpi .
110 CXXX #undef ALLOW_USE_MPI
111
112 C-- Control use of communication that might overlap computation.
113 C Under MPI selects/deselects "non-blocking" sends and receives.
114 #define ALLOW_ASYNC_COMMUNICATION
115 #undef ALLOW_ASYNC_COMMUNICATION
116 #undef ALWAYS_USE_ASYNC_COMMUNICATION
117 C-- Control use of communication that is atomic to computation.
118 C Under MPI selects/deselects "blocking" sends and receives.
119 #define ALLOW_SYNC_COMMUNICATION
120 #undef ALWAYS_USE_SYNC_COMMUNICATION
121
122 C-- Control XY periodicity in processor to grid mappings
123 C Note: Model code does not need to know whether a domain is
124 C periodic because it has overlap regions for every box.
125 C Model assume that these values have been
126 C filled in some way.
127 #undef ALWAYS_PREVENT_X_PERIODICITY
128 #undef ALWAYS_PREVENT_Y_PERIODICITY
129 #define CAN_PREVENT_X_PERIODICITY
130 #define CAN_PREVENT_Y_PERIODICITY
131
132 C-- disconnect tiles (no exchange between tiles, just fill-in edges
133 C assuming locally periodic subdomain)
134 #undef DISCONNECTED_TILES
135
136 C-- Always cumulate tile local-sum in the same order by applying MPI allreduce
137 C to array of tiles ; can get slower with large number of tiles (big set-up)
138 #define GLOBAL_SUM_ORDER_TILES
139
140 C-- Alternative way of doing global sum without MPI allreduce call
141 C but instead, explicit MPI send & recv calls. Expected to be slower.
142 #undef GLOBAL_SUM_SEND_RECV
143
144 C-- Alternative way of doing global sum on a single CPU
145 C to eliminate tiling-dependent roundoff errors. Note: This is slow.
146 #undef CG2D_SINGLECPU_SUM
147
148 C=== Other options (to add/remove pieces of code) ===
149 C-- Flag to turn on checking for errors from all threads and procs
150 C (calling S/R STOP_IF_ERROR) before stopping.
151 #define USE_ERROR_STOP
152
153 C-- Control use of communication with other component:
154 C allow to import and export from/to Coupler interface.
155 #undef COMPONENT_MODULE
156
157 C-- Activate some pieces of code for coupling to GEOS AGCM
158 #undef HACK_FOR_GMAO_CPL
159
160 #endif /* _CPP_EEOPTIONS_H_ */
161
162 #include "CPP_EEMACROS.h"
163

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