--- MITgcm/pkg/seaice/seaice_jfnk.F 2012/12/17 15:06:02 1.13 +++ MITgcm/pkg/seaice/seaice_jfnk.F 2013/01/17 08:51:15 1.16 @@ -1,8 +1,13 @@ -C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/pkg/seaice/seaice_jfnk.F,v 1.13 2012/12/17 15:06:02 mlosch Exp $ +C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/pkg/seaice/seaice_jfnk.F,v 1.16 2013/01/17 08:51:15 mlosch Exp $ C $Name: $ #include "SEAICE_OPTIONS.h" +C-- File seaice_jfnk.F: seaice jfnk dynamical solver S/R: +C-- Contents +C-- o SEAICE_JFNK +C-- o SEAICE_JFNK_UPDATE + CBOP C !ROUTINE: SEAICE_JFNK C !INTERFACE: @@ -10,7 +15,7 @@ C !DESCRIPTION: \bv C *==========================================================* -C | SUBROUTINE SEAICE_JFKF +C | SUBROUTINE SEAICE_JFNK C | o Ice dynamics using a Jacobian-free Newton-Krylov solver C | following J.-F. Lemieux et al. Improving the numerical C | convergence of viscous-plastic sea ice models with the @@ -55,6 +60,8 @@ LOGICAL DIFFERENT_MULTIPLE EXTERNAL DIFFERENT_MULTIPLE +C !LOCAL VARIABLES: +C === Local variables === C i,j,bi,bj :: loop indices INTEGER i,j,bi,bj C loop indices @@ -80,6 +87,8 @@ C u/vIceRes :: residual of sea-ice momentum equations _RL uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) _RL vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) +C vector version of the residuals + _RL resTmp (nVec,1,nSx,nSy) C du/vIce :: ice velocity increment to be added to u/vIce _RL duIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) _RL dvIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) @@ -90,8 +99,6 @@ _RL etaZPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) _RL dwatPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) CEOP - INTEGER n - _RL resTmp (nVec,1,nSx,nSy) C Initialise newtonIter = 0 @@ -142,12 +149,11 @@ newtonIter = newtonIter + 1 C Compute initial residual F(u), (includes computation of global C variables DWATN, zeta, and eta) - CALL SEAICE_CALC_RESIDUAL( - I uIce, vIce, - O uIceRes, vIceRes, - I newtonIter, 0, myTime, myIter, myThid ) -C probably not necessary, will be removed later: - CALL EXCH_UV_XY_RL( uIceRes, vIceRes,.TRUE.,myThid) + IF ( newtonIter .EQ. 1 ) CALL SEAICE_JFNK_UPDATE( + I duIce, dvIce, + U uIce, vIce, JFNKresidual, + O uIceRes, vIceRes, + I newtonIter, myTime, myIter, myThid ) C local copies of precomputed coefficients that are to stay C constant for the preconditioner DO bj=myByLo(myThid),myByHi(myThid) @@ -162,12 +168,6 @@ ENDDO ENDDO ENDDO -C Important: Compute the norm of the residual using the same scalar -C product that SEAICE_FGMRES does - CALL SEAICE_MAP2VEC(nVec,uIceRes,vIceRes,resTmp,.TRUE.,myThid) - CALL SEAICE_SCALPROD( - & nVec,1,1,1,resTmp,resTmp,JFNKresidual,myThid) - JFNKresidual = SQRT(JFNKresidual) C compute convergence criterion for linear preconditioned FGMRES JFNKgamma_lin = JFNKgamma_lin_max IF ( newtonIter.GT.1.AND.newtonIter.LE.100 @@ -254,22 +254,30 @@ IF ( krylovIter.EQ.SEAICEkrylovIterMax ) THEN krylovFails = krylovFails + 1 ENDIF +C Set the stopping criterion for the Newton iteration + IF ( newtonIter .EQ. 1 ) JFNKtol=JFNKgamma_nonlin*JFNKresidual C Update linear solution vector and return to Newton iteration +C Do a linesearch if necessary, and compute a new residual. +C Note that it should be possible to do the following operations +C at the beginning of the Newton iteration, thereby saving us from +C the extra call of seaice_jfnk_update, but unfortunately that +C changes the results, so we leave the stuff here for now. + CALL SEAICE_JFNK_UPDATE( + I duIce, dvIce, + U uIce, vIce, JFNKresidual, + O uIceRes, vIceRes, + I newtonIter, myTime, myIter, myThid ) +C reset du/vIce here instead of setting sol = 0 in seaice_fgmres_driver DO bj=myByLo(myThid),myByHi(myThid) DO bi=myBxLo(myThid),myBxHi(myThid) DO J=1-Oly,sNy+Oly DO I=1-Olx,sNx+Olx - uIce(I,J,bi,bj) = uIce(I,J,bi,bj)+duIce(I,J,bi,bj) - vIce(I,J,bi,bj) = vIce(I,J,bi,bj)+dvIce(I,J,bi,bj) -C reset du/vIce here instead of setting sol = 0 in seaice_fgmres_driver duIce(I,J,bi,bj)= 0. _d 0 dvIce(I,J,bi,bj)= 0. _d 0 ENDDO ENDDO ENDDO ENDDO -C Set the stopping criterion for the Newton iteration - IF ( newtonIter .EQ. 1 ) JFNKtol=JFNKgamma_nonlin*JFNKresidual ENDIF C end of Newton iterate ENDDO @@ -384,6 +392,141 @@ _END_MASTER( myThid ) ENDIF + RETURN + END + +C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| +CBOP +C !ROUTINE: SEAICE_JFNK_UPDATE +C !INTERFACE: + + SUBROUTINE SEAICE_JFNK_UPDATE( + I duIce, dvIce, + U uIce, vIce, JFNKresidual, + O uIceRes, vIceRes, + I newtonIter, myTime, myIter, myThid ) + +C !DESCRIPTION: \bv +C *==========================================================* +C | SUBROUTINE SEAICE_JFNK_UPDATE +C | o Update velocities with incremental solutions of FGMRES +C | o compute residual of updated solutions and do +C | o linesearch: +C | reduce update until residual is smaller than previous +C | one (input) +C *==========================================================* +C | written by Martin Losch, Jan 2013 +C *==========================================================* +C \ev + +C !USES: + IMPLICIT NONE + +C === Global variables === +#include "SIZE.h" +#include "EEPARAMS.h" +#include "PARAMS.h" +#include "SEAICE_SIZE.h" +#include "SEAICE_PARAMS.h" + +C !INPUT/OUTPUT PARAMETERS: +C === Routine arguments === +C myTime :: Simulation time +C myIter :: Simulation timestep number +C myThid :: my Thread Id. number +C newtonIter :: current iterate of Newton iteration + _RL myTime + INTEGER myIter + INTEGER myThid + INTEGER newtonIter +C JFNKresidual :: Residual at the beginning of the FGMRES iteration, +C changes with newtonIter (updated) + _RL JFNKresidual +C du/vIce :: ice velocity increment to be added to u/vIce (input) + _RL duIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) + _RL dvIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) +C u/vIce :: ice velocity increment to be added to u/vIce (updated) + _RL uIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) + _RL vIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) +C u/vIceRes :: residual of sea-ice momentum equations (output) + _RL uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) + _RL vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy) + +C !LOCAL VARIABLES: +C === Local variables === +C i,j,bi,bj :: loop indices + INTEGER i,j,bi,bj + INTEGER l + _RL resLoc, facLS + LOGICAL doLineSearch +C nVec :: size of the input vector(s) +C vector version of the residuals + INTEGER nVec + PARAMETER ( nVec = 2*sNx*sNy ) + _RL resTmp (nVec,1,nSx,nSy) +C + CHARACTER*(MAX_LEN_MBUF) msgBuf +CEOP + +C Initialise some local variables + l = 0 + resLoc = JFNKresidual + facLS = 1. _d 0 + doLineSearch = .TRUE. + DO WHILE ( doLineSearch ) +C Determine, if we need more iterations + doLineSearch = resLoc .GE. JFNKresidual +C Limit the maximum number of iterations arbitrarily to four + doLineSearch = doLineSearch .AND. l .LE. 4 +C For the first iteration du/vIce = 0 and there will be no +C improvement of the residual possible, so we do only the first +C iteration + IF ( newtonIter .EQ. 1 ) doLineSearch = .FALSE. +C Only start a linesearch after some Newton iterations + IF ( newtonIter .LE. SEAICE_JFNK_lsIter ) doLineSearch = .FALSE. +C Increment counter + l = l + 1 +C Create update + DO bj=myByLo(myThid),myByHi(myThid) + DO bi=myBxLo(myThid),myBxHi(myThid) + DO J=1-Oly,sNy+Oly + DO I=1-Olx,sNx+Olx + uIce(I,J,bi,bj) = uIce(I,J,bi,bj)+facLS*duIce(I,J,bi,bj) + vIce(I,J,bi,bj) = vIce(I,J,bi,bj)+facLS*dvIce(I,J,bi,bj) + ENDDO + ENDDO + ENDDO + ENDDO +C Compute current residual F(u), (includes re-computation of global +C variables DWATN, zeta, and eta, i.e. they are different after this) + CALL SEAICE_CALC_RESIDUAL( + I uIce, vIce, + O uIceRes, vIceRes, + I newtonIter, 0, myTime, myIter, myThid ) +C Important: Compute the norm of the residual using the same scalar +C product that SEAICE_FGMRES does + CALL SEAICE_MAP2VEC(nVec,uIceRes,vIceRes,resTmp,.TRUE.,myThid) + CALL SEAICE_SCALPROD(nVec,1,1,1,resTmp,resTmp,resLoc,myThid) + resLoc = SQRT(resLoc) +C some output diagnostics + IF ( debugLevel.GE.debLevA .AND. doLineSearch ) THEN + _BEGIN_MASTER( myThid ) + WRITE(msgBuf,'(2A,2(1XI6),3E12.5)') + & ' S/R SEAICE_JFNK_UPDATE: Newton iter, LSiter, ', + & 'facLS, JFNKresidual, resLoc = ', + & newtonIter, l, facLS, JFNKresidual, resLoc + CALL PRINT_MESSAGE( msgBuf, standardMessageUnit, + & SQUEEZE_RIGHT, myThid ) + _END_MASTER( myThid ) + ENDIF +C Get ready for the next iteration: after adding du/vIce in the first +C iteration, we substract 0.5*du/vIce from u/vIce in the next +C iterations, 0.25*du/vIce in the second, etc. + facLS = - 0.5 _d 0 * ABS(facLS) + ENDDO +C This is the new residual + JFNKresidual = resLoc + #endif /* SEAICE_ALLOW_DYNAMICS and SEAICE_CGRID and SEAICE_ALLOW_JFNK */ RETURN