| 1 | C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_jacvec.F,v 1.4 2013/02/28 17:12:48 mlosch Exp $ | 
| 2 | C $Name:  $ | 
| 3 |  | 
| 4 | #include "SEAICE_OPTIONS.h" | 
| 5 |  | 
| 6 | CBOP | 
| 7 | C     !ROUTINE: SEAICE_JACVEC | 
| 8 | C     !INTERFACE: | 
| 9 | SUBROUTINE SEAICE_JACVEC( | 
| 10 | I     uIceLoc, vIceLoc, uIceRes, vIceRes, | 
| 11 | U     duIce, dvIce, | 
| 12 | I     newtonIter, krylovIter, myTime, myIter, myThid ) | 
| 13 |  | 
| 14 | C     !DESCRIPTION: \bv | 
| 15 | C     *==========================================================* | 
| 16 | C     | SUBROUTINE SEAICE_JACVEC | 
| 17 | C     | o For Jacobian-free Newton-Krylov solver compute | 
| 18 | C     |   Jacobian times vector by finite difference approximation | 
| 19 | C     *==========================================================* | 
| 20 | C     | written by Martin Losch, Oct 2012 | 
| 21 | C     *==========================================================* | 
| 22 | C     \ev | 
| 23 |  | 
| 24 | C     !USES: | 
| 25 | IMPLICIT NONE | 
| 26 |  | 
| 27 | C     === Global variables === | 
| 28 | #include "SIZE.h" | 
| 29 | #include "EEPARAMS.h" | 
| 30 | #include "PARAMS.h" | 
| 31 | #include "DYNVARS.h" | 
| 32 | #include "GRID.h" | 
| 33 | #include "SEAICE_SIZE.h" | 
| 34 | #include "SEAICE_PARAMS.h" | 
| 35 | #include "SEAICE.h" | 
| 36 |  | 
| 37 | C     !INPUT/OUTPUT PARAMETERS: | 
| 38 | C     === Routine arguments === | 
| 39 | C     myTime :: Simulation time | 
| 40 | C     myIter :: Simulation timestep number | 
| 41 | C     myThid :: my Thread Id. number | 
| 42 | C     newtonIter :: current iterate of Newton iteration | 
| 43 | C     krylovIter :: current iterate of Krylov iteration | 
| 44 | _RL     myTime | 
| 45 | INTEGER myIter | 
| 46 | INTEGER myThid | 
| 47 | INTEGER newtonIter | 
| 48 | INTEGER krylovIter | 
| 49 | C     u/vIceLoc :: local copies of the current ice velocity | 
| 50 | _RL uIceLoc(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 51 | _RL vIceLoc(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 52 | C     u/vIceRes :: initial residual of this Newton iterate | 
| 53 | _RL uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 54 | _RL vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 55 | C     du/vIce   :: correction of ice velocities | 
| 56 | _RL duIce  (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 57 | _RL dvIce  (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 58 |  | 
| 59 | #ifdef SEAICE_ALLOW_JFNK | 
| 60 | C     Local variables: | 
| 61 | _RL utp     (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 62 | _RL vtp     (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 63 | C     u/vIceResP :: residual computed with u/vtp | 
| 64 | _RL uIceResP(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 65 | _RL vIceResP(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 66 |  | 
| 67 | C     i,j,bi,bj :: loop indices | 
| 68 | INTEGER i,j,bi,bj | 
| 69 | _RL epsilon, reps | 
| 70 | CEOP | 
| 71 | C     Instructions for using TAF or TAMC to generate exact Jacobian times | 
| 72 | C     vector operations: | 
| 73 | C | 
| 74 | C     1. make small_f | 
| 75 | C     2. cat seaice_calc_residual.f seaice_oceandrag_coeffs.f seaice_calc_strainrates.f seaice_calc_viscosities.f seaice_calc_rhs.f seaice_calc_lhs.f > taf_input.f | 
| 76 | C     3. staf -v1 -forward -toplevel seaice_calc_residual -input uIceLoc,viceLoc -output uIceRes,vIceRes taf_input.f | 
| 77 | C     4. insert content of taf_input_ftl.f at the end of this file | 
| 78 | C     5. add the following code and comment out the finite difference code | 
| 79 | C | 
| 80 | C     Instruction for using TAF 2.4 and higher (or staf with default -v2 | 
| 81 | C     starting with version 2.0): | 
| 82 | C | 
| 83 | C     1. make small_f | 
| 84 | C     2. staf -forward -toplevel seaice_calc_residual -input uIceLoc,viceLoc -output uIceRes,vIceRes seaice_calc_residual.f seaice_oceandrag_coeffs.f seaice_calc_strainrates.f seaice_calc_viscosities.f seaice_calc_rhs.f seaice_calc_lhs.f | 
| 85 | C     3. copy files seaice_*_tl.f to the corresponding seaice_*.f files, | 
| 86 | C        e.g. with this bash script: | 
| 87 | C     for file in `ls seaice_*_tl.f`; do | 
| 88 | C       nfile=`echo $file | awk -F_ '{printf "%s_%s_%s.f", $1,$2,$3}'`; | 
| 89 | C       \cp -f $file $nfile | 
| 90 | C     done | 
| 91 | C     4. add the following code, change "call g_seaice_calc_residual" to "call seaice_calc_residual_tl", and comment out the finite difference code | 
| 92 | CML      _RL g_duIce(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 93 | CML      _RL g_dvIce(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 94 | CML      _RL g_uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 95 | CML      _RL g_vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) | 
| 96 | CML | 
| 97 | CMLC     Initialise | 
| 98 | CML      DO bj=myByLo(myThid),myByHi(myThid) | 
| 99 | CML       DO bi=myBxLo(myThid),myBxHi(myThid) | 
| 100 | CML        DO J=1-Oly,sNy+Oly | 
| 101 | CML         DO I=1-Olx,sNx+Olx | 
| 102 | CML          g_duIce(I,J,bi,bj) = duice(I,J,bi,bj) | 
| 103 | CML          g_dvIce(I,J,bi,bj) = dvice(I,J,bi,bj) | 
| 104 | CML          g_uIceRes(I,J,bi,bj) = 0. _d 0 | 
| 105 | CML          g_vIceRes(I,J,bi,bj) = 0. _d 0 | 
| 106 | CML          uIceResP(I,J,bi,bj) = 0. _d 0 | 
| 107 | CML          vIceResP(I,J,bi,bj) = 0. _d 0 | 
| 108 | CML         ENDDO | 
| 109 | CML        ENDDO | 
| 110 | CML       ENDDO | 
| 111 | CML      ENDDO | 
| 112 | CML | 
| 113 | CML      CALL G_SEAICE_CALC_RESIDUAL( uIce, g_duice, vIce, | 
| 114 | CML     $g_dvice, uiceresp, g_uiceres, viceresp, g_viceres, newtoniter, | 
| 115 | CML     $kryloviter, mytime, myiter, mythid ) | 
| 116 | CMLCML      For staf -v2 replace the above with the below call | 
| 117 | CMLCML      CALL SEAICE_CALC_RESIDUAL_TL( uIce, g_duice, vIce, | 
| 118 | CMLCML     $g_dvice, uiceresp, g_uiceres, viceresp, g_viceres, newtoniter, | 
| 119 | CMLCML     $kryloviter, mytime, myiter, mythid ) | 
| 120 | CML | 
| 121 | CML      DO bj=myByLo(myThid),myByHi(myThid) | 
| 122 | CML       DO bi=myBxLo(myThid),myBxHi(myThid) | 
| 123 | CML        DO J=1-Oly,sNy+Oly | 
| 124 | CML         DO I=1-Olx,sNx+Olx | 
| 125 | CML          duice(I,J,bi,bj)=g_uiceres(I,J,bi,bj) | 
| 126 | CML          dvice(I,J,bi,bj)=g_viceres(I,J,bi,bj) | 
| 127 | CML         ENDDO | 
| 128 | CML        ENDDO | 
| 129 | CML       ENDDO | 
| 130 | CML      ENDDO | 
| 131 |  | 
| 132 | C     Initialise | 
| 133 | epsilon = SEAICE_JFNKepsilon | 
| 134 | reps    = 1. _d 0/epsilon | 
| 135 |  | 
| 136 | DO bj=myByLo(myThid),myByHi(myThid) | 
| 137 | DO bi=myBxLo(myThid),myBxHi(myThid) | 
| 138 | DO J=1-Oly,sNy+Oly | 
| 139 | DO I=1-Olx,sNx+Olx | 
| 140 | utp(I,J,bi,bj) = uIce(I,J,bi,bj) + epsilon * duIce(I,J,bi,bj) | 
| 141 | vtp(I,J,bi,bj) = vIce(I,J,bi,bj) + epsilon * dvIce(I,J,bi,bj) | 
| 142 | ENDDO | 
| 143 | ENDDO | 
| 144 | ENDDO | 
| 145 | ENDDO | 
| 146 |  | 
| 147 | C     Compute new residual F(u) | 
| 148 | CALL SEAICE_CALC_RESIDUAL( | 
| 149 | I     utp, vtp, | 
| 150 | O     uIceResP, vIceResP, | 
| 151 | I     newtonIter, krylovIter, myTime, myIter, myThid ) | 
| 152 |  | 
| 153 | C     approximate Jacobian times vector by one-sided finite differences | 
| 154 | C     and store in du/vIce | 
| 155 | DO bj = myByLo(myThid),myByHi(myThid) | 
| 156 | DO bi = myBxLo(myThid),myBxHi(myThid) | 
| 157 | DO I = 1, sNx | 
| 158 | DO J = 1, sNy | 
| 159 | duIce(I,J,bi,bj) = | 
| 160 | &         (uIceResP(I,J,bi,bj)-uIceRes(I,J,bi,bj))*reps | 
| 161 | dvIce(I,J,bi,bj) = | 
| 162 | &         (vIceResP(I,J,bi,bj)-vIceRes(I,J,bi,bj))*reps | 
| 163 | ENDDO | 
| 164 | ENDDO | 
| 165 | ENDDO | 
| 166 | ENDDO | 
| 167 |  | 
| 168 | #endif /* SEAICE_ALLOW_JFNK */ | 
| 169 |  | 
| 170 | RETURN | 
| 171 | END |