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C $Header: /u/gcmpack/MITgcm/pkg/flt/flt_bilinear.F,v 1.4 2009/01/04 00:58:23 jmc Exp $ |
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C $Name: $ |
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|
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#include "FLT_OPTIONS.h" |
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|
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C-- Contents |
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C-- o FLT_BILINEAR |
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C-- o FLT_TRILINEAR |
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C-- o FLT_BILINEAR2D |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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SUBROUTINE FLT_BILINEAR( |
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I ix, jy, |
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O uu, |
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I var, |
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I kl, nu, bi, bj, myThid ) |
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|
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C ================================================================== |
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C SUBROUTINE FLT_BILINEAR |
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C ================================================================== |
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C o Bilinear scheme to interpolate variable to particle position |
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C given by its fractional (real) index ix,jy location |
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C ================================================================== |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C == global variables == |
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#include "SIZE.h" |
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|
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C == routine arguments == |
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_RL ix, jy |
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_RL uu |
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_RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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INTEGER kl, nu, bi, bj, myThid |
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|
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C == local variables == |
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INTEGER i1, j1, i2, j2, klp |
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_RL ddx, ddy |
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_RL u11, u12, u22, u21 |
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|
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C == end of interface == |
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|
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C-- to choose the u box in which the particle is found |
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C nu=0 for T, S |
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C nu=1 for u |
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C nu=2 for v |
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C nu=3 for Vorticity |
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C nu=4 for w |
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|
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IF ( kl.LT.1 .OR. kl.GT.Nr ) THEN |
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c WRITE(msgbuf,'(A,I8)') |
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c & ' FLT_BILINEAR: illegal value for kl=',kl |
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c CALL PRINT_ERROR( msgbuf, myThid ) |
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STOP 'ABNORMAL END: S/R FLT_BILINEAR' |
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ENDIF |
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|
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C-- find x-index according to grid-location of variable |
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IF ( MOD(nu,2).EQ.0 ) THEN |
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i1 = INT(ix) |
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ddx = ix - DFLOAT(i1) |
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ELSE |
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i1 = NINT(ix) |
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ddx = 0.5 _d 0 + ix - DFLOAT(i1) |
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ENDIF |
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C-- find y-index according to grid-location of variable |
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IF ( MOD(nu,4).LE.1 ) THEN |
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j1 = INT(jy) |
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ddy = jy - DFLOAT(j1) |
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ELSE |
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j1 = NINT(jy) |
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ddy = 0.5 _d 0 + jy - DFLOAT(j1) |
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ENDIF |
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|
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C-- Set the higher index for interpolation |
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i2 = i1 + 1 |
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j2 = j1 + 1 |
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|
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C-- No need to change start/end index : use array overlap if needed |
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|
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C-- bilinear interpolation (from numerical recipes) |
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IF (nu.LE.3) THEN |
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uu = ( (1.-ddx)*(1.-ddy)*var(i1,j1,kl,bi,bj) |
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& + ddx * ddy *var(i2,j2,kl,bi,bj) ) |
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& + ( ddx *(1.-ddy)*var(i2,j1,kl,bi,bj) |
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& + (1.-ddx)* ddy *var(i1,j2,kl,bi,bj) ) |
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ELSE |
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klp = MIN(kl+1,Nr) |
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u11 = ( var(i1,j1,kl,bi,bj)+var(i1,j1,klp,bi,bj) )*0.5 _d 0 |
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u21 = ( var(i2,j1,kl,bi,bj)+var(i2,j1,klp,bi,bj) )*0.5 _d 0 |
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u22 = ( var(i2,j2,kl,bi,bj)+var(i2,j2,klp,bi,bj) )*0.5 _d 0 |
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u12 = ( var(i1,j2,kl,bi,bj)+var(i1,j2,klp,bi,bj) )*0.5 _d 0 |
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uu = ( (1.-ddx)*(1.-ddy)*u11 |
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& + ddx * ddy *u22 ) |
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& + ( ddx *(1.-ddy)*u21 |
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& + (1.-ddx)* ddy *u12 ) |
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ENDIF |
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|
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|
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RETURN |
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END |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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SUBROUTINE FLT_TRILINEAR( |
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I ix, jy, kz, |
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O uu, |
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I var, |
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I nu, bi, bj, myThid ) |
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|
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C ================================================================== |
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C SUBROUTINE FLT_TRILINEAR |
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C ================================================================== |
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C o Trilinear scheme to interpolate variable to particle position |
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C given by its fractional (real) index ix,jy,kz location |
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C This routine is a straight forward generalization of the |
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C bilinear interpolation scheme. |
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C |
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C started: 2004.05.28 Antti Westerlund (antti.westerlund@fimr.fi) |
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C and Sergio Jaramillo (sju@eos.ubc.ca). |
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C (adopted from SUBROUTINE bilinear by Arne Biastoch) |
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C ================================================================== |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C == global variables == |
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#include "SIZE.h" |
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|
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C == routine arguments == |
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_RL ix, jy, kz |
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_RL uu |
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_RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy) |
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INTEGER nu, bi, bj, myThid |
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|
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C == local variables == |
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INTEGER i1, j1, k1, i2, j2, k2 |
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_RL ddx, ddy, ddz |
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|
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C == end of interface == |
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|
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C to choose the u box in which the particle is found |
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C nu=0 for T, S |
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C nu=1 for u |
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C nu=2 for v |
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C nu=3 for Vorticity |
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C nu=4 for w |
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|
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C-- find x-index according to grid-location of variable |
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IF ( MOD(nu,2).EQ.0 ) THEN |
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i1 = INT(ix) |
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ddx = ix - DFLOAT(i1) |
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ELSE |
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i1 = NINT(ix) |
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ddx = 0.5 _d 0 + ix - DFLOAT(i1) |
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ENDIF |
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C-- find y-index according to grid-location of variable |
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IF ( MOD(nu,4).LE.1 ) THEN |
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j1 = INT(jy) |
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ddy = jy - DFLOAT(j1) |
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ELSE |
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j1 = NINT(jy) |
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ddy = 0.5 _d 0 + jy - DFLOAT(j1) |
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ENDIF |
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C-- find z-index according to grid-location of variable |
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IF ( nu.LE.3 ) THEN |
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k1 = INT(kz) |
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ddz = kz - DFLOAT(k1) |
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ELSE |
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k1 = NINT(kz) |
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ddz = 0.5 _d 0 + kz - DFLOAT(k1) |
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ENDIF |
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|
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C-- Set the higher index for interpolation |
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i2 = i1 + 1 |
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j2 = j1 + 1 |
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k2 = k1 + 1 |
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|
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C-- No need to change start/end horizontal index : use array overlap if needed |
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C-- Need to adjust start/end vertical index : |
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k1 = MIN( MAX( k1, 1 ), Nr ) |
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k2 = MIN( MAX( k2, 1 ), Nr ) |
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|
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C Trilinear interpolation, a straight forward generalization |
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C of the bilinear interpolation scheme. |
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uu = (1.-ddz)*( ( (1.-ddx)*(1.-ddy)*var(i1,j1,k1,bi,bj) |
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& + ddx * ddy *var(i2,j2,k1,bi,bj) ) |
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& + ( ddx *(1.-ddy)*var(i2,j1,k1,bi,bj) |
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& + (1.-ddx)* ddy *var(i1,j2,k1,bi,bj) ) ) |
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& + ddz *( ( (1.-ddx)*(1.-ddy)*var(i1,j1,k2,bi,bj) |
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& + ddx * ddy *var(i2,j2,k2,bi,bj) ) |
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& + ( ddx*(1.-ddy) *var(i2,j1,k2,bi,bj) |
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& + (1.-ddx)* ddy *var(i1,j2,k2,bi,bj) ) ) |
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|
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RETURN |
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END |
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|
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C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
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|
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SUBROUTINE FLT_BILINEAR2D( |
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I ix, jy, |
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O uu, |
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I var, |
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I nu, bi, bj, myThid ) |
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|
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C ================================================================== |
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C SUBROUTINE FLT_BILINEAR2D |
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C ================================================================== |
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C o Bilinear scheme to interpolate 2-D variable to particle position |
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C given by its fractional (real) index ix,jy location |
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C |
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C started: Arne Biastoch abiastoch@ucsd.edu 13-Jan-2000 |
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C (adopted from SUBROUTINE bilinear) |
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C ================================================================== |
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|
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C !USES: |
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IMPLICIT NONE |
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|
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C == global variables == |
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#include "SIZE.h" |
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|
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C == routine arguments == |
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_RL ix, jy |
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_RL uu |
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_RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) |
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INTEGER nu, bi, bj, myThid |
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|
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C == local variables == |
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INTEGER i1, j1, i2, j2 |
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_RL ddx, ddy |
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|
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C == end of interface == |
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|
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C to choose the u box in which the particle is found |
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C nu=0 for T, S |
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C nu=1 for u |
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C nu=2 for v |
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C nu=3 for Vorticity |
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C nu=4 for w |
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|
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C-- find x-index according to grid-location of variable |
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IF ( MOD(nu,2).EQ.0 ) THEN |
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i1 = INT(ix) |
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ddx = ix - DFLOAT(i1) |
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ELSE |
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i1 = NINT(ix) |
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ddx = 0.5 _d 0 + ix - DFLOAT(i1) |
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ENDIF |
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C-- find y-index according to grid-location of variable |
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IF ( MOD(nu,4).LE.1 ) THEN |
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j1 = INT(jy) |
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ddy = jy - DFLOAT(j1) |
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ELSE |
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j1 = NINT(jy) |
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ddy = 0.5 _d 0 + jy - DFLOAT(j1) |
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ENDIF |
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|
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C-- Set the higher index for interpolation |
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i2 = i1 + 1 |
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j2 = j1 + 1 |
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|
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C-- No need to change start/end index : use array overlap if needed |
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|
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C bilinear interpolation (from numerical recipes) |
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uu = ( (1.-ddx)*(1.-ddy)*var(i1,j1,bi,bj) |
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& + ddx * ddy *var(i2,j2,bi,bj) ) |
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& + ( ddx *(1.-ddy)*var(i2,j1,bi,bj) |
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& + (1.-ddx)* ddy *var(i1,j2,bi,bj) ) |
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|
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RETURN |
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END |