/[MITgcm]/MITgcm/model/src/the_model_main.F
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Contents of /MITgcm/model/src/the_model_main.F

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Revision 1.15 - (show annotations) (download)
Mon Jun 22 15:26:26 1998 UTC (25 years, 11 months ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint9, checkpoint8
Changes since 1.14: +5 -2 lines
Various changes including time-dependant forcing:
 o logic for controlling external forcing fields now allows
   for time-dependant forcing: load_external_fields.F
 o genmake.dec needed a special line for the above file.
 o theta* and salt* time-stepping algorithm were re-implemented.
The 4x4 global configuration has been "double-checked" against
CNH's version. However, we do not assume any responsibility for
the correctness of this code ...  8-)

1 C $Header: /u/gcmpack/models/MITgcmUV/model/src/the_model_main.F,v 1.14 1998/06/18 13:56:06 adcroft Exp $
2
3 #include "CPP_EEOPTIONS.h"
4
5 SUBROUTINE THE_MODEL_MAIN(myThid)
6 C /==========================================================\
7 C | SUBROUTINE THE_MODEL_MAIN |
8 C | o Master controlling routine for model using the MITgcm |
9 C | UV parallel wrapper. |
10 C |==========================================================|
11 C | THE_MODEL_MAIN is invoked by the MITgcm UV parallel |
12 C | wrapper with a single integer argument "myThid". This |
13 C | variable identifies the thread number of an instance of |
14 C | THE_MODEL_MAIN. Each instance of THE_MODEL_MAIN works |
15 C | on a particular region of the models domain and |
16 C | synchronises with other instances as necessary. The |
17 C | routine has to "understand" the MITgcm parallel |
18 C | environment and the numerical algorithm. Editing this |
19 C | routine is best done with some knowledge of both aspects.|
20 C | Notes |
21 C | ===== |
22 C | C*P* comments indicating place holders for which code is |
23 C | presently being developed. |
24 C \==========================================================/
25 C
26 C Call Tree
27 C =========
28 C
29 C main ( eesupp )
30 C |
31 C .
32 C .
33 C . Generic environment initialisation ( see eesupp/src and
34 C . eesupp/inc )
35 C . multiple threads and/or processes are created in here
36 C .
37 C .
38 C .
39 C |
40 C |-THE_MODEL_MAIN - Begin specific model. One instance
41 C | | of this codes exists for each thread
42 C | | and/or instance. Each instance manages
43 C | | a specifc set of tiles.
44 C | |
45 C | |--INITIALISE
46 C | | o Set initial conditions and model configuration
47 C | | Topography, hydrography, timestep, grid, etc..
48 C | |
49 C ==> | | ** Time stepping loop starts here **
50 C | | |
51 C /|\ | |
52 C | | |--LOAD_EXTERNAL_DATA
53 C /|\ | | o Load and/or set time dependent forcing fields
54 C | | |
55 C /|\ | |--DYNAMICS
56 C | | | o Evaluate "forward" terms
57 C /|\ | |
58 C | | |--DO_THE_MODEL_IO
59 C /|\ | | o Write model state
60 C | | |
61 C /|\ | |--SOLVE_FOR_PRESSURE
62 C | | | o Find pressure field to keep flow non-divergent
63 C /|\ | |
64 C | | |--DO_GTERM_BLOCKING_EXCHANGES
65 C /|\ | | o Update overlap regions
66 C | | |
67 C /|\ | |--WRITE_CHECKPOINT
68 C | | | o Write restart file(s)
69 C /|\ | |
70 C | | |
71 C |<== | | ** Time stepping loop finishes here **
72 C | |
73 C | |--WRITE_STATE
74 C | |--WRITE_CHECKPOINT
75 C |
76 C .
77 C .
78 C . Generic environment termination ( see eesupp/src and
79 C . eesupp/inc )
80 C .
81 C .
82
83 C == Global variables ===
84 #include "SIZE.h"
85 #include "EEPARAMS.h"
86 #include "PARAMS.h"
87 #include "CG2D.h"
88 #include "DYNVARS.h"
89 #include "AVER.h"
90
91 C == Routine arguments ==
92 C myThid - Thread number for this instance of the routine.
93 INTEGER myThid
94
95 C == Local variables ==
96 C Note: Under the multi-threaded model myCurrentIter and
97 C myCurrentTime are local variables passed around as routine
98 C arguments. Although this is fiddly it saves the need to
99 C impose additional synchronisation points when they are
100 C updated.
101 C myCurrentIter - Iteration counter for this thread
102 C myCurrentTime - Time counter for this thread
103 C I - Loop counter
104 INTEGER I, myCurrentIter
105 REAL myCurrentTime
106
107 C-- Set model initial conditions
108 CALL INITIALISE( myThid )
109 myCurrentTime = startTime
110 myCurrentIter = nIter0
111
112 C-- Dump for start state
113 CALL WRITE_STATE( .TRUE., myCurrentTime, myCurrentIter, myThid )
114
115 C-- Begin time stepping loop
116 DO I=1, nTimeSteps
117
118 C-- Load forcing/external data fields
119 CALL LOAD_EXTERNAL_FIELDS( myCurrentTime, myCurrentIter, myThid )
120
121 C-- Step forward fields and calculate time tendency terms
122 CALL DYNAMICS( myCurrentTime, myCurrentIter, myThid )
123
124 C-- Do time averages
125 IF (taveFreq.GT.0.) THEN
126 CALL DO_TIME_AVERAGES( myCurrentTime, myCurrentIter, myThid )
127 ENDIF
128
129 C-- Do IO if needed.
130 C Note:
131 C =====
132 C At this point model arrays hold U,V,T,S at "time-level" N
133 C and cg2d_x at "time-level" N-1/2 where N = I+timeLevBase-1.
134 C By convention this is taken to be the model "state".
135 CALL DO_THE_MODEL_IO( myCurrentTime, myCurrentIter, myThid )
136
137 C-- Solve elliptic equation(s).
138 C Two-dimensional only for conventional hydrostatic or
139 C three-dimensional for non-hydrostatic and/or IGW scheme.
140 CALL SOLVE_FOR_PRESSURE( myThid )
141
142 C-- Do "blocking" sends and receives for tendency "overlap" terms
143 CALL DO_GTERM_BLOCKING_EXCHANGES( myThid )
144
145 myCurrentIter = myCurrentIter + 1
146 myCurrentTime = myCurrentTime + deltaTClock
147
148 C-- Save state for restarts
149 C Note:
150 C =====
151 C Because of the ordering of the timestepping code and
152 C tendency term code at end of loop model arrays hold
153 C U,V,T,S at "time-level" N but gu, gv, gs, gt, guNM1,...
154 C at "time-level" N+1/2 (guNM1 at "time-level" N+1/2 is
155 C gu at "time-level" N-1/2) and cg2d_x at "time-level" N+1/2.
156 C where N = I+timeLevBase-1
157 C Thus a checkpoint contains U.0000000000, GU.0000000001 and
158 C cg2d_x.0000000001 in the indexing scheme used for the model
159 C "state" files. This example is referred to as a checkpoint
160 C at time level 1
161 CALL WRITE_CHECKPOINT( .FALSE., myCurrentTime, myCurrentIter, myThid )
162
163 ENDDO
164
165 C-- Final checkpoint (incase the in-loop checkpoint was missed)
166 CALL WRITE_CHECKPOINT( .TRUE., myCurrentTime, myCurrentIter, myThid )
167
168 C-- Step-forward U/V/Theta/Salt for purposes of final I/O dump
169 CALL DYNAMICS( myCurrentTime, myCurrentIter, myThid )
170
171 C-- Do time averages
172 IF (taveFreq.GT.0.) THEN
173 CALL DO_TIME_AVERAGES( myCurrentTime, myCurrentIter, myThid )
174 ENDIF
175
176 C-- Dump for end state
177 CALL WRITE_STATE( .FALSE., myCurrentTime, myCurrentIter, myThid )
178
179
180 RETURN
181 END

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