/[MITgcm]/MITgcm/model/src/cg2d.F
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revision 1.29 by jmc, Thu Mar 8 20:49:08 2001 UTC revision 1.30 by adcroft, Fri Mar 9 20:45:09 2001 UTC
# Line 6  C $Name$ Line 6  C $Name$
6        SUBROUTINE CG2D(          SUBROUTINE CG2D(  
7       I                cg2d_b,       I                cg2d_b,
8       U                cg2d_x,       U                cg2d_x,
9         U                tolerance,
10         O                residual,
11         U                numIters,
12       I                myThid )       I                myThid )
13  C     /==========================================================\  C     /==========================================================\
14  C     | SUBROUTINE CG2D                                          |  C     | SUBROUTINE CG2D                                          |
# Line 40  C     === Global data === Line 43  C     === Global data ===
43  #include "SURFACE.h"  #include "SURFACE.h"
44    
45  C     === Routine arguments ===  C     === Routine arguments ===
46  C     myThid - Thread on which I am working.  C     myThid    - Thread on which I am working.
47        INTEGER myThid  C     cg2d_b    - The source term or "right hand side"
48        _RL  cg2d_x(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)  C     cg2d_x    - The solution
49    C     tolerance - Entry: the tolerance of accuracy to solve to
50    C                 Exit:  the initial residual before any iterations
51    C     residual  - Exit:  the actual residual reached
52    C     numIters  - Entry: the maximum number of iterations allowed
53    C                 Exit:  the actual number of iterations used
54        _RL  cg2d_b(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)        _RL  cg2d_b(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
55          _RL  cg2d_x(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
56          _RL  tolerance
57          _RL  residual
58          INTEGER numIters
59          INTEGER myThid
60    
61  C     === Local variables ====  C     === Local variables ====
62  C     actualIts      - Number of iterations taken  C     actualIts      - Number of iterations taken
# Line 62  C                   or they converge at Line 74  C                   or they converge at
74  C     err         - Measure of residual of Ax - b, usually the norm.  C     err         - Measure of residual of Ax - b, usually the norm.
75  C     I, J, N     - Loop counters ( N counts CG iterations )  C     I, J, N     - Loop counters ( N counts CG iterations )
76        INTEGER actualIts        INTEGER actualIts
77        _RL    actualResidual        _RL    actualResidual,initialResidual
78        INTEGER bi, bj                      INTEGER bi, bj              
79        INTEGER I, J, it2d        INTEGER I, J, it2d
80        _RL    err        _RL    err
# Line 211  C     WRITE(6,*) ' mythid, err = ', myth Line 223  C     WRITE(6,*) ' mythid, err = ', myth
223        actualIts      = 0        actualIts      = 0
224        actualResidual = SQRT(err)        actualResidual = SQRT(err)
225  C     _BARRIER  C     _BARRIER
226        _BEGIN_MASTER( myThid )  c     _BEGIN_MASTER( myThid )
227         WRITE(0,'(A,I6,1PE30.14)') ' CG2D iters, err = ',  c      WRITE(0,'(A,I6,1PE30.14)') ' CG2D iters, err = ',
228       & actualIts, actualResidual  c    & actualIts, actualResidual
229        _END_MASTER( )  c     _END_MASTER( )
230          initialResidual=actualResidual
231    
232  C     >>>>>>>>>>>>>>> BEGIN SOLVER <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<  C     >>>>>>>>>>>>>>> BEGIN SOLVER <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
233        DO 10 it2d=1, cg2dMaxIters        DO 10 it2d=1, numIters
234    
235  CcnhDebugStarts  CcnhDebugStarts
236  C      WRITE(0,*) ' CG2D: Iteration ',it2d-1,' residual = ',  C      WRITE(0,*) ' CG2D: Iteration ',it2d-1,' residual = ',
237  C    &  actualResidual  C    &  actualResidual
238  CcnhDebugEnds  CcnhDebugEnds
239         IF ( err .LT. cg2dTargetResidual ) GOTO 11         IF ( err .LT. tolerance ) GOTO 11
240  C--    Solve preconditioning equation and update  C--    Solve preconditioning equation and update
241  C--    conjugate direction vector "s".  C--    conjugate direction vector "s".
242         eta_qrN = 0. _d 0         eta_qrN = 0. _d 0
# Line 373  C--   Un-normalise the answer Line 386  C--   Un-normalise the answer
386  C     The following exchange was moved up to solve_for_pressure  C     The following exchange was moved up to solve_for_pressure
387  C     for compatibility with TAMC.  C     for compatibility with TAMC.
388  C     _EXCH_XY_R8(cg2d_x, myThid )  C     _EXCH_XY_R8(cg2d_x, myThid )
389        _BEGIN_MASTER( myThid )  c     _BEGIN_MASTER( myThid )
390         WRITE(0,'(A,I6,1PE30.14)') ' CG2D iters, err = ',  c      WRITE(0,'(A,I6,1PE30.14)') ' CG2D iters, err = ',
391       & actualIts, actualResidual  c    & actualIts, actualResidual
392        _END_MASTER( )  c     _END_MASTER( )
393    
394    C--   Return parameters to caller
395          tolerance=initialResidual
396          residual=actualResidual
397          numIters=actualIts
398    
399  CcnhDebugStarts  CcnhDebugStarts
400  C     CALL PLOT_FIELD_XYRL( cg2d_x, 'CALC_MOM_RHS CG2D_X' , 1, myThid )  C     CALL PLOT_FIELD_XYRL( cg2d_x, 'CALC_MOM_RHS CG2D_X' , 1, myThid )
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