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C $Header: /u/gcmpack/models/MITgcmUV/model/src/the_model_main.F,v 1.8 1998/05/25 20:05:55 cnh Exp $ |
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#include "CPP_EEOPTIONS.h" |
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SUBROUTINE THE_MODEL_MAIN(myThid) |
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C /==========================================================\ |
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C | SUBROUTINE THE_MODEL_MAIN | |
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C | o Master controlling routine for model using the MITgcm | |
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C | UV parallel wrapper. | |
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C |==========================================================| |
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C | THE_MODEL_MAIN is invoked by the MITgcm UV parallel | |
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C | wrapper with a single integer argument "myThid". This | |
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C | variable identifies the thread number of an instance of | |
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C | THE_MODEL_MAIN. Each instance of THE_MODEL_MAIN works | |
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C | on a particular region of the models domain and | |
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C | synchronises with other instances as necessary. The | |
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C | routine has to "understand" the MITgcm parallel | |
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C | environment and the numerical algorithm. Editing this | |
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C | routine is best done with some knowledge of both aspects.| |
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C | Notes | |
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C | ===== | |
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C | C*P* comments indicating place holders for which code is | |
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C | presently being developed. | |
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C \==========================================================/ |
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C == Global variables === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "CG2D.h" |
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#include "DYNVARS.h" |
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C == Routine arguments == |
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C myThid - Thread number for this instance of the routine. |
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INTEGER myThid |
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C == Local variables == |
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C Note: Under the multi-threaded model myCurrentIter and |
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C myCurrentTime are local variables passed around as routine |
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C arguments. Although this is fiddly it saves the need to |
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C impose additional synchronisation points when they are |
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C updated. |
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C myCurrentIter - Iteration counter for this thread |
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C myCurrentTime - Time counter for this thread |
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C I - Loop counter |
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INTEGER I, myCurrentIter |
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REAL myCurrentTime |
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C-- Set model initial conditions |
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CALL INITIALISE( myThid ) |
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myCurrentTime = startTime |
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myCurrentIter = nIter0 |
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C-- Initialise time-stepping (predictor variables are carried in G) |
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CALL INIT_PREDICTOR( myThid ) |
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C-- Begin time stepping loop |
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DO I=1, nTimeSteps |
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C-- Load offline tracer fields |
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IF ( MOD(myCurrentIter,numStepsPerPickup) .EQ. 1 ) THEN |
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C I/O |
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C o Writes to arrays are performed by their own thread (to ensure |
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C physical memory allocation will pair with thread). |
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C o Thread 1 reads into a buffer. |
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C CALL LOAD_OFFLINE_FIELDS( myCurrentTime, myCurrentIter, myThid ) |
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ENDIF |
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C-- Step forward fields and calculate time tendency terms |
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CALL DYNAMICS( myCurrentTime, myCurrentIter, myThid ) |
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C-- Do IO if needed. |
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C Note: |
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C ===== |
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C At this point model arrays hold U,V,T,S at "time-level" N |
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C and cg2d_x at "time-level" N-1/2 where N = I+timeLevBase-1. |
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C By convention this is taken to be the model "state". |
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CALL DO_THE_MODEL_IO( myCurrentTime, myCurrentIter, myThid ) |
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C-- Solve elliptic equation(s). |
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C Two-dimensional only for conventional hydrostatic or |
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C three-dimensional for non-hydrostatic and/or IGW scheme. |
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CALL SOLVE_FOR_PRESSURE( myThid ) |
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C-- Do "blocking" sends and receives for tendency "overlap" terms |
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CALL DO_GTERM_BLOCKING_EXCHANGES( myThid ) |
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myCurrentIter = myCurrentIter + 1 |
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myCurrentTime = myCurrentTime + deltaTClock |
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C-- Save state for restarts |
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C Note: |
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C ===== |
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C Because of the ordereing of the timestepping code and |
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C tendency term code at end of loop model arrays hold |
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C U,V,T,S at "time-level" N but gu, gv, gs, gt, guNM1,... |
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C at "time-level" N+1/2 (guNM1 at "time-level" N+1/2 is |
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C gu at "time-level" N-1/2) and cg2d_x at "time-level" N+1/2. |
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C where N = I+timeLevBase-1 |
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C Thus a checkpoint contains U.0000000000, GU.0000000001 and |
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C cg2d_x.0000000001 in the indexing scheme used for the model |
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C "state" files. This example is referred to as a checkpoint |
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C at time level 1 |
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CALL WRITE_CHECKPOINT( .FALSE., myCurrentTime, myCurrentIter, myThid ) |
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ENDDO |
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C-- Dump for end state and final checkpoint |
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CALL WRITE_STATE( myCurrentTime, myCurrentIter, myThid ) |
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CALL WRITE_CHECKPOINT( .TRUE., myCurrentTime, myCurrentIter, myThid ) |
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RETURN |
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END |
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