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C $Header: /u/gcmpack/MITgcm/model/src/adams_bashforth2.F,v 1.9 2013/02/19 13:42:19 jmc Exp $ |
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C $Name: $ |
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|
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#include "CPP_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: ADAMS_BASHFORTH2 |
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C !INTERFACE: |
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SUBROUTINE ADAMS_BASHFORTH2( |
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I bi, bj, kArg, kSize, |
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U gTracer, gTrNm1, |
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O AB_gTr, |
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I startAB, myIter, myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | S/R ADAMS_BASHFORTH2 |
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C | o Extrapolate forward in time using quasi-second order |
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C | Adams-Bashforth method. |
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C *==========================================================* |
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C | Either apply to tendency (kArg>0) at level k=kArg, |
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C | or apply to state variable (kArg=0) for all levels |
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C *==========================================================* |
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C \ev |
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|
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C !USES: |
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IMPLICIT NONE |
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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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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine Arguments == |
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C bi,bj :: Tile indices |
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C kArg :: if >0: apply AB on tendency at level k=kArg |
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C :: if =0: apply AB on state variable and process all levels |
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C kSize :: 3rd dimension of tracer and tendency arrays |
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C gTracer :: in: Tendency/State at current time |
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C :: out (kArg >0): Extrapolated Tendency at current time |
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C gTrNm1 :: in: Tendency/State at previous time |
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C :: out: (kArg >0) Save tendency at current time |
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C :: out: (kArg =0) Extrapolated State at current time |
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C AB_gTr :: Adams-Bashforth tendency increment |
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C startAB :: number of previous time level available to start/restart AB |
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C myIter :: Current time step number |
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C myThid :: my Thread Id. number |
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INTEGER bi, bj, kArg, kSize |
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_RL gTracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy,kSize) |
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_RL gTrNm1 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,kSize) |
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_RL AB_gTr (1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER startAB |
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INTEGER myIter, myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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C k :: level index |
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C i,j :: Loop counters |
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C abFac :: Adams bashforth extrapolation factor |
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INTEGER i, j, k |
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_RL abFac |
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CEOP |
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|
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C Adams-Bashforth extrapolation factor |
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IF ( myIter.EQ.nIter0 .AND. startAB.EQ.0 ) THEN |
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abFac = 0. _d 0 |
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ELSE |
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abFac = 0.5 _d 0 + abEps |
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ENDIF |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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IF ( kArg.EQ.0 ) THEN |
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C- Extrapolate forward in time the state variable, with AB weights: |
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DO k=1,kSize |
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DO j=1-OLy,sNy+OLy |
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DO i=1-OLx,sNx+OLx |
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AB_gTr(i,j) = abFac*( gTracer(i,j,k) - gTrNm1(i,j,k) ) |
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gTrNm1(i,j,k) = gTracer(i,j,k) + AB_gTr(i,j) |
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ENDDO |
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ENDDO |
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ENDDO |
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ELSE |
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C- Extrapolate forward in time the tendency, with AB weights: |
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k = kArg |
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DO j=1-OLy,sNy+OLy |
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DO i=1-OLx,sNx+OLx |
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AB_gTr(i,j) = abFac*( gTracer(i,j,k) - gTrNm1(i,j,k) ) |
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gTrNm1(i,j,k) = gTracer(i,j,k) |
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gTracer(i,j,k) = gTracer(i,j,k) + AB_gTr(i,j) |
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ENDDO |
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ENDDO |
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ENDIF |
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|
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RETURN |
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END |