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

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Revision 1.8 - (hide annotations) (download)
Mon May 25 20:05:55 1998 UTC (26 years ago) by cnh
Branch: MAIN
CVS Tags: checkpoint4, checkpoint3
Changes since 1.7: +2 -2 lines
Added extra IO features
 - runtime on/off flags
 - more reporting of configuration

1 cnh 1.8 C $Header: /u/gcmpack/models/MITgcmUV/model/src/the_model_main.F,v 1.7 1998/05/21 18:25:49 cnh Exp $
2 cnh 1.1
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    
26     C == Global variables ===
27     #include "SIZE.h"
28     #include "EEPARAMS.h"
29     #include "PARAMS.h"
30     #include "CG2D.h"
31     #include "DYNVARS.h"
32    
33     C == Routine arguments ==
34     C myThid - Thread number for this instance of the routine.
35 cnh 1.6 INTEGER myThid
36 cnh 1.1
37     C == Local variables ==
38 cnh 1.7 C Note: Under the multi-threaded model myCurrentIter and
39     C myCurrentTime are local variables passed around as routine
40     C arguments. Although this is fiddly it saves the need to
41     C impose additional synchronisation points when they are
42     C updated.
43 cnh 1.1 C myCurrentIter - Iteration counter for this thread
44     C myCurrentTime - Time counter for this thread
45     C I - Loop counter
46     INTEGER I, myCurrentIter
47     REAL myCurrentTime
48    
49     C-- Set model initial conditions
50     CALL INITIALISE( myThid )
51     myCurrentTime = startTime
52     myCurrentIter = nIter0
53    
54     C-- Begin time stepping loop
55     DO I=1, nTimeSteps
56 cnh 1.4
57 cnh 1.1 C-- Load offline tracer fields
58     IF ( MOD(myCurrentIter,numStepsPerPickup) .EQ. 1 ) THEN
59     C I/O
60     C o Writes to arrays are performed by their own thread (to ensure
61     C physical memory allocation will pair with thread).
62     C o Thread 1 reads into a buffer.
63     C CALL LOAD_OFFLINE_FIELDS( myCurrentTime, myCurrentIter, myThid )
64     ENDIF
65    
66     C-- Step forward fields and calculate time tendency terms
67 cnh 1.8 CALL DYNAMICS( myCurrentTime, myCurrentIter, myThid )
68 cnh 1.1
69 cnh 1.7 C-- Do IO if needed.
70     C Note:
71     C =====
72     C At this point model arrays hold U,V,T,S at "time-level" N
73     C and cg2d_x at "time-level" N-1/2 where N = I+timeLevBase-1.
74     C By convention this is taken to be the model "state".
75     CALL DO_THE_MODEL_IO( myCurrentTime, myCurrentIter, myThid )
76    
77 cnh 1.1 C-- Solve elliptic equation(s).
78 cnh 1.7 C Two-dimensional only for conventional hydrostatic or
79     C three-dimensional for non-hydrostatic and/or IGW scheme.
80 cnh 1.1 CALL SOLVE_FOR_PRESSURE( myThid )
81    
82     C-- Do "blocking" sends and receives for tendency "overlap" terms
83     CALL DO_GTERM_BLOCKING_EXCHANGES( myThid )
84    
85     myCurrentIter = myCurrentIter + 1
86 cnh 1.7 myCurrentTime = myCurrentTime + deltaTClock
87 cnh 1.1
88     C-- Save state for restarts
89 cnh 1.7 C Note:
90     C =====
91     C Because of the ordereing of the timestepping code and
92     C tendency term code at end of loop model arrays hold
93     C U,V,T,S at "time-level" N but gu, gv, gs, gt, guNM1,...
94     C at "time-level" N+1/2 (guNM1 at "time-level" N+1/2 is
95     C gu at "time-level" N-1/2) and cg2d_x at "time-level" N+1/2.
96     C where N = I+timeLevBase-1
97     C Thus a checkpoint contains U.0000000000, GU.0000000001 and
98     C cg2d_x.0000000001 in the indexing scheme used for the model
99     C "state" files. This example is referred to as a checkpoint
100     C at time level 1
101     CALL WRITE_CHECKPOINT( .FALSE., myCurrentTime, myCurrentIter, myThid )
102 cnh 1.1
103     ENDDO
104 cnh 1.7
105     C-- Dump for end state and final checkpoint
106     CALL WRITE_STATE( myCurrentTime, myCurrentIter, myThid )
107     CALL WRITE_CHECKPOINT( .TRUE., myCurrentTime, myCurrentIter, myThid )
108    
109 cnh 1.1
110     RETURN
111     END

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