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C $Header: /u/gcmpack/MITgcm/pkg/streamice/streamice_tridiag_solve.F,v 1.2 2013/06/21 20:49:51 jmc Exp $ |
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C $Name: $ |
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#include "STREAMICE_OPTIONS.h" |
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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CBOP |
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SUBROUTINE STREAMICE_TRIDIAG_SOLVE( |
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U cg_Uin, ! x-velocities |
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U cg_Vin, ! x-velocities |
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U cg_Bu, ! force in x dir |
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I A_uu, ! section of matrix that multiplies u and projects on u |
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I umask, |
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I myThid ) |
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C /============================================================\ |
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C | SUBROUTINE | |
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C | o | |
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C |============================================================| |
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C | | |
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C \============================================================/ |
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IMPLICIT NONE |
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|
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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 "STREAMICE.h" |
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#include "STREAMICE_CG.h" |
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|
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_RL cg_Uin (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL cg_Vin (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL cg_Bu (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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_RL A_uu (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy,-1:1,-1:1) |
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_RS umask (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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INTEGER myThid |
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|
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INTEGER iMin,iMax,i,j,k |
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_RL aMat(1:Nx) |
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_RL bMat(1:Nx) |
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_RL cMat(1:Nx) |
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_RL yMat(1:Nx) |
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_RL bet(1:Nx) |
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_RL tmpvar |
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INTEGER errCode |
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! CALL WRITE_FLD_XY_RL ("taud_tri","",cg_Bu,0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_m1m1","",A_uu(:,:,:,:,-1,-1),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_m1_0","",A_uu(:,:,:,:,-1,0),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_m1p1","",A_uu(:,:,:,:,-1,1),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_0_m1","",A_uu(:,:,:,:,0,-1),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_0_0","",A_uu(:,:,:,:,0,0),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_0_p1","",A_uu(:,:,:,:,0,1),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_p1m1","",A_uu(:,:,:,:,1,-1),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_p1_0","",A_uu(:,:,:,:,1,0),0,mythid) |
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! CALL WRITE_FLD_XY_RL ("A_p1p1","",A_uu(:,:,:,:,1,1),0,mythid) |
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IF (nPx.gt.1 .or. nSx.gt.1) THEN |
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STOP 'must be serial for tridiag solve' |
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ENDIF |
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errCode = 0 |
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imax = 0 |
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iMin = 2 |
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do i=imin,Nx |
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if (umask(i,1,1,1).eq.1.0) THEN |
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|
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aMat(i)=0.0 |
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bmat(i)=0.0 |
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cmat(i)=0.0 |
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ymat(i)=0.0 |
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do j=-1,1 |
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do k=1,3 |
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aMat(i) = amat(i)+A_uu(i,k,1,1,-1,j) |
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bMat(i) = bmat(i)+A_uu(i,k,1,1,0,j) |
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cMat(i) = cmat(i)+A_uu(i,k,1,1,1,j) |
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enddo |
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yMat(i) = ymat(i)+cg_Bu(i,j+2,1,1) |
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enddo |
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else |
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iMax = i-1 |
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exit |
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endif |
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enddo |
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IF(imax.eq.0) THEN |
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imax=Nx |
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ENDIF |
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|
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IF ( bMat(imin).NE.0. _d 0 ) THEN |
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bet(imin) = 1. _d 0 / bMat(imin) |
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ELSE |
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bet(imin) = 0. _d 0 |
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errCode = 1 |
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ENDIF |
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|
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DO i=imin+1,imax |
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tmpvar = bmat(i) - amat(i)*cmat(i-1)*bet(i-1) |
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IF ( tmpvar .NE. 0. _d 0 ) THEN |
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bet(i) = 1. _d 0 / tmpvar |
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ELSE |
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bet(i) = 0. _d 0 |
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errCode = 1 |
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ENDIF |
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ENDDO |
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ymat(imin) = ymat(imin)*bet(imin) |
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DO i=imin+1,imax |
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ymat(i) = ( ymat(i) |
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& - amat(i)*ymat(i-1) |
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& )*bet(i) |
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ENDDO |
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DO i=imax-1,imin,-1 |
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ymat(i) = ymat(i) |
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& - cmat(i)*bet(i)*ymat(i+1) |
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ENDDO |
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|
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DO j=1,sNy |
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DO i=imin,imax |
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cg_Uin (i,j,1,1) = ymat(i) |
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ENDDO |
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ENDDO |
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|
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DO j=1,sNy |
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DO i=1,sNx |
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cg_Vin (i,j,1,1) = 0. _d 0 |
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ENDDO |
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ENDDO |
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print *, "ERRORCODE", errcode |
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RETURN |
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END |