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C $Header: /u/gcmpack/MITgcm/model/src/adams_bashforth2.F,v 1.6 2005/04/15 14:11:01 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, k, |
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U gTracer, gTrNm1, |
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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 tendencies forward in time using |
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C | quasi-second order Adams-Bashforth method. |
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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,k :: Tile and level indices |
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C gTracer :: Tendency at current time ( generally units of quantity/sec ) |
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C gTrNm1 :: Tendency at previous time ( generally units of quantity/sec ) |
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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 :: Thread number of this thread |
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INTEGER bi,bj,k |
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_RL gTracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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_RL gTrNm1 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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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 i,j :: Loop counters |
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C ab15, ab05 :: Adams bashforth extrapolation weights. |
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INTEGER i,j |
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_RL ab15,ab05 |
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_RL gTrtmp |
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CEOP |
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|
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C Adams-Bashforth timestepping weights |
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IF ( myIter.EQ.nIter0 .AND. startAB.EQ.0 ) THEN |
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ab15 = 1. _d 0 |
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ab05 = 0. _d 0 |
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ELSE |
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ab15 = 1.5 _d 0 + abEps |
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ab05 = -( 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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C- Compute effective G-term with Adams-Bashforth weights: |
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DO j=1-Oly,sNy+Oly |
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DO i=1-Olx,sNx+Olx |
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gTrtmp = ab15*gTracer(i,j,k,bi,bj) |
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& + ab05*gTrNm1(i,j,k,bi,bj) |
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gTrNm1(i,j,k,bi,bj) = gTracer(i,j,k,bi,bj) |
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gTracer(i,j,k,bi,bj) = gTrtmp |
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ENDDO |
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ENDDO |
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|
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RETURN |
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END |
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