/[MITgcm]/MITgcm/pkg/seaice/seaice_jfnk.F
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Revision 1.24 - (hide annotations) (download)
Tue Feb 4 18:30:31 2014 UTC (11 years, 5 months ago) by mlosch
Branch: MAIN
Changes since 1.23: +15 -15 lines
  - rename recently introduced parameters from (wrong name) AB to
    BDF (backward difference time discretisation)
  - retire runtime parameters SEAICEuseAB2, SEAICE_abEps

The scheme is still experimental and does not work to my satisfaction,
but at least the name is not approprate

1 mlosch 1.24 C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_jfnk.F,v 1.23 2013/05/30 14:07:19 mlosch Exp $
2 mlosch 1.1 C $Name: $
3    
4     #include "SEAICE_OPTIONS.h"
5    
6 mlosch 1.15 C-- File seaice_jfnk.F: seaice jfnk dynamical solver S/R:
7     C-- Contents
8     C-- o SEAICE_JFNK
9     C-- o SEAICE_JFNK_UPDATE
10    
11 mlosch 1.1 CBOP
12     C !ROUTINE: SEAICE_JFNK
13     C !INTERFACE:
14     SUBROUTINE SEAICE_JFNK( myTime, myIter, myThid )
15    
16     C !DESCRIPTION: \bv
17     C *==========================================================*
18 mlosch 1.15 C | SUBROUTINE SEAICE_JFNK
19 mlosch 1.1 C | o Ice dynamics using a Jacobian-free Newton-Krylov solver
20     C | following J.-F. Lemieux et al. Improving the numerical
21     C | convergence of viscous-plastic sea ice models with the
22     C | Jacobian-free Newton-Krylov method. J. Comp. Phys. 229,
23     C | 2840-2852 (2010).
24     C | o The logic follows JFs code.
25     C *==========================================================*
26     C | written by Martin Losch, Oct 2012
27     C *==========================================================*
28     C \ev
29    
30     C !USES:
31     IMPLICIT NONE
32    
33     C === Global variables ===
34     #include "SIZE.h"
35     #include "EEPARAMS.h"
36     #include "PARAMS.h"
37     #include "DYNVARS.h"
38     #include "GRID.h"
39     #include "SEAICE_SIZE.h"
40     #include "SEAICE_PARAMS.h"
41     #include "SEAICE.h"
42    
43     #ifdef ALLOW_AUTODIFF_TAMC
44     # include "tamc.h"
45     #endif
46    
47     C !INPUT/OUTPUT PARAMETERS:
48     C === Routine arguments ===
49     C myTime :: Simulation time
50     C myIter :: Simulation timestep number
51     C myThid :: my Thread Id. number
52     _RL myTime
53     INTEGER myIter
54     INTEGER myThid
55    
56 mlosch 1.21 #ifdef SEAICE_ALLOW_JFNK
57 mlosch 1.5 C !FUNCTIONS:
58     LOGICAL DIFFERENT_MULTIPLE
59     EXTERNAL DIFFERENT_MULTIPLE
60 mlosch 1.1
61 mlosch 1.16 C !LOCAL VARIABLES:
62     C === Local variables ===
63 mlosch 1.1 C i,j,bi,bj :: loop indices
64     INTEGER i,j,bi,bj
65     C loop indices
66 mlosch 1.5 INTEGER newtonIter
67     INTEGER krylovIter, krylovFails
68 mlosch 1.13 INTEGER totalKrylovItersLoc, totalNewtonItersLoc
69 mlosch 1.5 C FGMRES flag that determines amount of output messages of fgmres
70     INTEGER iOutFGMRES
71     C FGMRES flag that indicates what fgmres wants us to do next
72 mlosch 1.1 INTEGER iCode
73 mlosch 1.13 _RL JFNKresidual
74 mlosch 1.1 _RL JFNKresidualKm1
75     C parameters to compute convergence criterion
76 mlosch 1.22 _RL JFNKgamma_lin
77 mlosch 1.1 _RL FGMRESeps
78     _RL JFNKtol
79 mlosch 1.24 C backward differences extrapolation factors
80     _RL bdfFac, bdfAlpha
81 mlosch 1.23 C
82 mlosch 1.1 _RL recip_deltaT
83     LOGICAL JFNKconverged, krylovConverged
84 mlosch 1.9 LOGICAL writeNow
85 mlosch 1.1 CHARACTER*(MAX_LEN_MBUF) msgBuf
86 jmc 1.20
87 mlosch 1.1 C u/vIceRes :: residual of sea-ice momentum equations
88     _RL uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
89     _RL vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
90 mlosch 1.24 C extra time level required for backward difference time stepping
91 mlosch 1.23 _RL duIcNm1(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
92     _RL dvIcNm1(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
93 mlosch 1.1 C du/vIce :: ice velocity increment to be added to u/vIce
94     _RL duIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
95     _RL dvIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
96 jmc 1.20 C precomputed (= constant per Newton iteration) versions of
97 mlosch 1.2 C zeta, eta, and DWATN, press
98     _RL zetaPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
99     _RL etaPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
100 mlosch 1.8 _RL etaZPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
101 mlosch 1.2 _RL dwatPre (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
102 mlosch 1.1 CEOP
103    
104     C Initialise
105 mlosch 1.5 newtonIter = 0
106     krylovFails = 0
107     totalKrylovItersLoc = 0
108     JFNKconverged = .FALSE.
109     JFNKtol = 0. _d 0
110     JFNKresidual = 0. _d 0
111     JFNKresidualKm1 = 0. _d 0
112     FGMRESeps = 0. _d 0
113     recip_deltaT = 1. _d 0 / SEAICE_deltaTdyn
114    
115     iOutFGMRES=0
116 mlosch 1.12 C with iOutFgmres=1, seaice_fgmres prints the residual at each iteration
117     IF ( debugLevel.GE.debLevC .AND.
118 mlosch 1.5 & DIFFERENT_MULTIPLE( SEAICE_monFreq, myTime, deltaTClock ) )
119     & iOutFGMRES=1
120    
121 mlosch 1.24 C backward difference extrapolation factors
122     bdfFac = 0. _d 0
123     IF ( SEAICEuseBDF2 ) THEN
124     IF ( myIter.EQ.nIter0 .AND. SEAICEmomStartBDF.EQ.0 ) THEN
125     bdfFac = 0. _d 0
126 mlosch 1.23 ELSE
127 mlosch 1.24 bdfFac = 0.5 _d 0
128 mlosch 1.23 ENDIF
129     ENDIF
130 mlosch 1.24 bdfAlpha = 1. _d 0 + bdfFac
131 mlosch 1.23
132 mlosch 1.1 DO bj=myByLo(myThid),myByHi(myThid)
133     DO bi=myBxLo(myThid),myBxHi(myThid)
134 jmc 1.20 DO J=1-OLy,sNy+OLy
135     DO I=1-OLx,sNx+OLx
136 mlosch 1.1 uIceRes(I,J,bi,bj) = 0. _d 0
137     vIceRes(I,J,bi,bj) = 0. _d 0
138     duIce (I,J,bi,bj) = 0. _d 0
139     dvIce (I,J,bi,bj) = 0. _d 0
140 mlosch 1.23 ENDDO
141     ENDDO
142     C cycle ice velocities
143     DO J=1-OLy,sNy+OLy
144     DO I=1-OLx,sNx+OLx
145 mlosch 1.24 duIcNm1(I,J,bi,bj) = uIce(I,J,bi,bj) * bdfAlpha
146     & + ( uIce(I,J,bi,bj) - uIceNm1(I,J,bi,bj) ) * bdfFac
147     dvIcNm1(I,J,bi,bj) = vIce(I,J,bi,bj) * bdfAlpha
148     & + ( vIce(I,J,bi,bj) - vIceNm1(I,J,bi,bj) ) * bdfFac
149 mlosch 1.1 uIceNm1(I,J,bi,bj) = uIce(I,J,bi,bj)
150     vIceNm1(I,J,bi,bj) = vIce(I,J,bi,bj)
151     ENDDO
152     ENDDO
153 mlosch 1.23 IF ( .NOT.SEAICEuseIMEX ) THEN
154 mlosch 1.1 C Compute things that do no change during the Newton iteration:
155 jmc 1.20 C sea-surface tilt and wind stress:
156 mlosch 1.23 C FORCEX/Y0 - mass*(abA*u/vIceNm1+abB*(u/vIceNm1-u/vIceNm2))/deltaT
157 jmc 1.20 DO J=1-OLy,sNy+OLy
158     DO I=1-OLx,sNx+OLx
159 mlosch 1.1 FORCEX(I,J,bi,bj) = FORCEX0(I,J,bi,bj)
160 mlosch 1.23 & + seaiceMassU(I,J,bi,bj)*duIcNm1(I,J,bi,bj)*recip_deltaT
161 mlosch 1.1 FORCEY(I,J,bi,bj) = FORCEY0(I,J,bi,bj)
162 mlosch 1.23 & + seaiceMassV(I,J,bi,bj)*dvIcNm1(I,J,bi,bj)*recip_deltaT
163 mlosch 1.1 ENDDO
164     ENDDO
165 mlosch 1.23 ENDIF
166 mlosch 1.1 ENDDO
167     ENDDO
168     C Start nonlinear Newton iteration: outer loop iteration
169     DO WHILE ( newtonIter.LT.SEAICEnewtonIterMax .AND.
170     & .NOT.JFNKconverged )
171     newtonIter = newtonIter + 1
172     C Compute initial residual F(u), (includes computation of global
173     C variables DWATN, zeta, and eta)
174 jmc 1.20 IF ( newtonIter .EQ. 1 ) CALL SEAICE_JFNK_UPDATE(
175     I duIce, dvIce,
176 mlosch 1.15 U uIce, vIce, JFNKresidual,
177     O uIceRes, vIceRes,
178     I newtonIter, myTime, myIter, myThid )
179 mlosch 1.1 C local copies of precomputed coefficients that are to stay
180     C constant for the preconditioner
181     DO bj=myByLo(myThid),myByHi(myThid)
182     DO bi=myBxLo(myThid),myBxHi(myThid)
183 jmc 1.20 DO j=1-OLy,sNy+OLy
184     DO i=1-OLx,sNx+OLx
185 mlosch 1.10 zetaPre(I,J,bi,bj) = zeta(I,J,bi,bj)
186     etaPre(I,J,bi,bj) = eta(I,J,bi,bj)
187     etaZPre(I,J,bi,bj) = etaZ(I,J,bi,bj)
188     dwatPre(I,J,bi,bj) = DWATN(I,J,bi,bj)
189 mlosch 1.1 ENDDO
190     ENDDO
191     ENDDO
192     ENDDO
193     C compute convergence criterion for linear preconditioned FGMRES
194     JFNKgamma_lin = JFNKgamma_lin_max
195 mlosch 1.18 IF ( newtonIter.GT.1.AND.newtonIter.LE.SEAICE_JFNK_tolIter
196 mlosch 1.1 & .AND.JFNKresidual.LT.JFNKres_t ) THEN
197 mlosch 1.22 C Eisenstat and Walker (1996), eq.(2.6)
198     JFNKgamma_lin = SEAICE_JFNKphi
199     & *( JFNKresidual/JFNKresidualKm1 )**SEAICE_JFNKalpha
200 mlosch 1.1 JFNKgamma_lin = min(JFNKgamma_lin_max, JFNKgamma_lin)
201     JFNKgamma_lin = max(JFNKgamma_lin_min, JFNKgamma_lin)
202     ENDIF
203     C save the residual for the next iteration
204     JFNKresidualKm1 = JFNKresidual
205 jmc 1.20
206 mlosch 1.1 C The Krylov iteration using FGMRES, the preconditioner is LSOR
207     C for now. The code is adapted from SEAICE_LSR, but heavily stripped
208     C down.
209     C krylovIter is mapped into "its" in seaice_fgmres and is incremented
210     C in that routine
211     krylovIter = 0
212     iCode = 0
213 jmc 1.20
214 mlosch 1.1 JFNKconverged = JFNKresidual.LT.JFNKtol
215 jmc 1.20
216 mlosch 1.1 C do Krylov loop only if convergence is not reached
217 jmc 1.20
218 mlosch 1.1 IF ( .NOT.JFNKconverged ) THEN
219 jmc 1.20
220 mlosch 1.1 C start Krylov iteration (FGMRES)
221 jmc 1.20
222 mlosch 1.1 krylovConverged = .FALSE.
223     FGMRESeps = JFNKgamma_lin * JFNKresidual
224 jmc 1.20 DO WHILE ( .NOT.krylovConverged )
225 mlosch 1.1 C solution vector sol = du/vIce
226     C residual vector (rhs) Fu = u/vIceRes
227 jmc 1.20 C output work vectors wk1, -> input work vector wk2
228    
229 mlosch 1.1 CALL SEAICE_FGMRES_DRIVER(
230 jmc 1.20 I uIceRes, vIceRes,
231 mlosch 1.1 U duIce, dvIce, iCode,
232 mlosch 1.5 I FGMRESeps, iOutFGMRES,
233 mlosch 1.1 I newtonIter, krylovIter, myTime, myIter, myThid )
234     C FGMRES returns iCode either asking for an new preconditioned vector
235     C or product of matrix (Jacobian) times vector. For iCode = 0, terminate
236     C iteration
237     IF (iCode.EQ.1) THEN
238 jmc 1.20 C Call preconditioner
239 mlosch 1.7 IF ( SOLV_MAX_ITERS .GT. 0 )
240 jmc 1.20 & CALL SEAICE_PRECONDITIONER(
241     U duIce, dvIce,
242     I zetaPre, etaPre, etaZpre, dwatPre,
243 mlosch 1.1 I newtonIter, krylovIter, myTime, myIter, myThid )
244     ELSEIF (iCode.GE.2) THEN
245     C Compute Jacobian times vector
246     CALL SEAICE_JACVEC(
247     I uIce, vIce, uIceRes, vIceRes,
248 jmc 1.20 U duIce, dvIce,
249 mlosch 1.1 I newtonIter, krylovIter, myTime, myIter, myThid )
250     ENDIF
251     krylovConverged = iCode.EQ.0
252     C End of Krylov iterate
253     ENDDO
254 mlosch 1.5 totalKrylovItersLoc = totalKrylovItersLoc + krylovIter
255 mlosch 1.1 C some output diagnostics
256     IF ( debugLevel.GE.debLevA ) THEN
257 mlosch 1.5 _BEGIN_MASTER( myThid )
258 jmc 1.20 totalNewtonItersLoc =
259 mlosch 1.13 & SEAICEnewtonIterMax*(myIter-nIter0)+newtonIter
260 jmc 1.20 WRITE(msgBuf,'(2A,2(1XI6),2E12.5)')
261 mlosch 1.13 & ' S/R SEAICE_JFNK: Newton iterate / total, ',
262     & 'JFNKgamma_lin, initial norm = ',
263     & newtonIter, totalNewtonItersLoc,
264     & JFNKgamma_lin,JFNKresidual
265     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
266     & SQUEEZE_RIGHT, myThid )
267 mlosch 1.1 WRITE(msgBuf,'(3(A,I6))')
268 jmc 1.20 & ' S/R SEAICE_JFNK: Newton iterate / total = ',newtonIter,
269 mlosch 1.13 & ' / ', totalNewtonItersLoc,
270 mlosch 1.1 & ', Nb. of FGMRES iterations = ', krylovIter
271     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
272     & SQUEEZE_RIGHT, myThid )
273 mlosch 1.5 _END_MASTER( myThid )
274 mlosch 1.1 ENDIF
275     IF ( krylovIter.EQ.SEAICEkrylovIterMax ) THEN
276 mlosch 1.5 krylovFails = krylovFails + 1
277 mlosch 1.1 ENDIF
278 mlosch 1.17 C Set the stopping criterion for the Newton iteration and the
279     C criterion for the transition from accurate to approximate FGMRES
280     IF ( newtonIter .EQ. 1 ) THEN
281     JFNKtol=JFNKgamma_nonlin*JFNKresidual
282     IF ( JFNKres_tFac .NE. UNSET_RL )
283     & JFNKres_t = JFNKresidual * JFNKres_tFac
284     ENDIF
285 mlosch 1.1 C Update linear solution vector and return to Newton iteration
286 mlosch 1.15 C Do a linesearch if necessary, and compute a new residual.
287     C Note that it should be possible to do the following operations
288     C at the beginning of the Newton iteration, thereby saving us from
289     C the extra call of seaice_jfnk_update, but unfortunately that
290     C changes the results, so we leave the stuff here for now.
291 jmc 1.20 CALL SEAICE_JFNK_UPDATE(
292     I duIce, dvIce,
293 mlosch 1.15 U uIce, vIce, JFNKresidual,
294     O uIceRes, vIceRes,
295     I newtonIter, myTime, myIter, myThid )
296     C reset du/vIce here instead of setting sol = 0 in seaice_fgmres_driver
297 mlosch 1.1 DO bj=myByLo(myThid),myByHi(myThid)
298     DO bi=myBxLo(myThid),myBxHi(myThid)
299 jmc 1.20 DO J=1-OLy,sNy+OLy
300     DO I=1-OLx,sNx+OLx
301 mlosch 1.4 duIce(I,J,bi,bj)= 0. _d 0
302     dvIce(I,J,bi,bj)= 0. _d 0
303 mlosch 1.1 ENDDO
304     ENDDO
305     ENDDO
306     ENDDO
307     ENDIF
308     C end of Newton iterate
309     ENDDO
310 jmc 1.20
311 mlosch 1.5 C-- Output diagnostics
312 jmc 1.20
313 mlosch 1.6 IF ( SEAICE_monFreq .GT. 0. _d 0 ) THEN
314 mlosch 1.5 C Count iterations
315 mlosch 1.6 totalJFNKtimeSteps = totalJFNKtimeSteps + 1
316     totalNewtonIters = totalNewtonIters + newtonIter
317     totalKrylovIters = totalKrylovIters + totalKrylovItersLoc
318 mlosch 1.5 C Record failure
319 mlosch 1.6 totalKrylovFails = totalKrylovFails + krylovFails
320     IF ( newtonIter .EQ. SEAICEnewtonIterMax ) THEN
321 jmc 1.20 totalNewtonFails = totalNewtonFails + 1
322 mlosch 1.6 ENDIF
323 mlosch 1.5 ENDIF
324     C Decide whether it is time to dump and reset the counter
325 mlosch 1.9 writeNow = DIFFERENT_MULTIPLE(SEAICE_monFreq,
326 jmc 1.20 & myTime+deltaTClock, deltaTClock)
327 mlosch 1.9 #ifdef ALLOW_CAL
328     IF ( useCAL ) THEN
329 jmc 1.20 CALL CAL_TIME2DUMP(
330 mlosch 1.9 I zeroRL, SEAICE_monFreq, deltaTClock,
331     U writeNow,
332     I myTime+deltaTclock, myIter+1, myThid )
333     ENDIF
334     #endif
335     IF ( writeNow ) THEN
336 mlosch 1.5 _BEGIN_MASTER( myThid )
337 jmc 1.20 WRITE(msgBuf,'(A)')
338 mlosch 1.5 &' // ======================================================='
339     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
340     & SQUEEZE_RIGHT, myThid )
341     WRITE(msgBuf,'(A)') ' // Begin JFNK statistics'
342     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
343     & SQUEEZE_RIGHT, myThid )
344 jmc 1.20 WRITE(msgBuf,'(A)')
345 mlosch 1.5 &' // ======================================================='
346     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
347     & SQUEEZE_RIGHT, myThid )
348 jmc 1.20 WRITE(msgBuf,'(A,I10)')
349 mlosch 1.5 & ' %JFNK_MON: time step = ', myIter+1
350     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
351     & SQUEEZE_RIGHT, myThid )
352 jmc 1.20 WRITE(msgBuf,'(A,I10)')
353 mlosch 1.5 & ' %JFNK_MON: Nb. of time steps = ', totalJFNKtimeSteps
354     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
355     & SQUEEZE_RIGHT, myThid )
356 jmc 1.20 WRITE(msgBuf,'(A,I10)')
357 mlosch 1.5 & ' %JFNK_MON: Nb. of Newton steps = ', totalNewtonIters
358     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
359     & SQUEEZE_RIGHT, myThid )
360 jmc 1.20 WRITE(msgBuf,'(A,I10)')
361 mlosch 1.5 & ' %JFNK_MON: Nb. of Krylov steps = ', totalKrylovIters
362     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
363     & SQUEEZE_RIGHT, myThid )
364 jmc 1.20 WRITE(msgBuf,'(A,I10)')
365 mlosch 1.5 & ' %JFNK_MON: Nb. of Newton failures = ', totalNewtonFails
366     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
367     & SQUEEZE_RIGHT, myThid )
368 jmc 1.20 WRITE(msgBuf,'(A,I10)')
369 mlosch 1.5 & ' %JFNK_MON: Nb. of Krylov failures = ', totalKrylovFails
370     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
371     & SQUEEZE_RIGHT, myThid )
372 jmc 1.20 WRITE(msgBuf,'(A)')
373 mlosch 1.5 &' // ======================================================='
374     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
375     & SQUEEZE_RIGHT, myThid )
376 mlosch 1.11 WRITE(msgBuf,'(A)') ' // End JFNK statistics'
377 mlosch 1.5 CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
378     & SQUEEZE_RIGHT, myThid )
379 jmc 1.20 WRITE(msgBuf,'(A)')
380 mlosch 1.5 &' // ======================================================='
381     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
382     & SQUEEZE_RIGHT, myThid )
383     _END_MASTER( myThid )
384     C reset and start again
385     totalJFNKtimeSteps = 0
386     totalNewtonIters = 0
387     totalKrylovIters = 0
388     totalKrylovFails = 0
389     totalNewtonFails = 0
390     ENDIF
391    
392     C Print more debugging information
393 mlosch 1.1 IF ( debugLevel.GE.debLevA ) THEN
394     IF ( newtonIter .EQ. SEAICEnewtonIterMax ) THEN
395 mlosch 1.5 _BEGIN_MASTER( myThid )
396 jmc 1.20 WRITE(msgBuf,'(A,I10)')
397 mlosch 1.1 & ' S/R SEAICE_JFNK: JFNK did not converge in timestep ',
398 mlosch 1.5 & myIter+1
399 mlosch 1.1 CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
400     & SQUEEZE_RIGHT, myThid )
401 mlosch 1.5 _END_MASTER( myThid )
402 mlosch 1.1 ENDIF
403 mlosch 1.5 IF ( krylovFails .GT. 0 ) THEN
404     _BEGIN_MASTER( myThid )
405 jmc 1.20 WRITE(msgBuf,'(A,I4,A,I10)')
406 mlosch 1.1 & ' S/R SEAICE_JFNK: FGMRES did not converge ',
407 mlosch 1.5 & krylovFails, ' times in timestep ', myIter+1
408 mlosch 1.1 CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
409     & SQUEEZE_RIGHT, myThid )
410 mlosch 1.5 _END_MASTER( myThid )
411 mlosch 1.1 ENDIF
412 mlosch 1.5 _BEGIN_MASTER( myThid )
413 jmc 1.20 WRITE(msgBuf,'(A,I6,A,I10)')
414 mlosch 1.1 & ' S/R SEAICE_JFNK: Total number FGMRES iterations = ',
415 mlosch 1.5 & totalKrylovItersLoc, ' in timestep ', myIter+1
416     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
417     & SQUEEZE_RIGHT, myThid )
418     _END_MASTER( myThid )
419 mlosch 1.1 ENDIF
420    
421 mlosch 1.15 RETURN
422     END
423    
424 mlosch 1.16 C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
425 mlosch 1.15 CBOP
426     C !ROUTINE: SEAICE_JFNK_UPDATE
427     C !INTERFACE:
428    
429 jmc 1.20 SUBROUTINE SEAICE_JFNK_UPDATE(
430     I duIce, dvIce,
431 mlosch 1.15 U uIce, vIce, JFNKresidual,
432     O uIceRes, vIceRes,
433     I newtonIter, myTime, myIter, myThid )
434    
435     C !DESCRIPTION: \bv
436     C *==========================================================*
437     C | SUBROUTINE SEAICE_JFNK_UPDATE
438     C | o Update velocities with incremental solutions of FGMRES
439     C | o compute residual of updated solutions and do
440     C | o linesearch:
441     C | reduce update until residual is smaller than previous
442     C | one (input)
443     C *==========================================================*
444     C | written by Martin Losch, Jan 2013
445     C *==========================================================*
446     C \ev
447    
448     C !USES:
449     IMPLICIT NONE
450    
451     C === Global variables ===
452     #include "SIZE.h"
453     #include "EEPARAMS.h"
454     #include "PARAMS.h"
455     #include "SEAICE_SIZE.h"
456     #include "SEAICE_PARAMS.h"
457    
458     C !INPUT/OUTPUT PARAMETERS:
459     C === Routine arguments ===
460     C myTime :: Simulation time
461     C myIter :: Simulation timestep number
462     C myThid :: my Thread Id. number
463     C newtonIter :: current iterate of Newton iteration
464     _RL myTime
465     INTEGER myIter
466     INTEGER myThid
467     INTEGER newtonIter
468     C JFNKresidual :: Residual at the beginning of the FGMRES iteration,
469     C changes with newtonIter (updated)
470     _RL JFNKresidual
471     C du/vIce :: ice velocity increment to be added to u/vIce (input)
472     _RL duIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
473     _RL dvIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
474     C u/vIce :: ice velocity increment to be added to u/vIce (updated)
475     _RL uIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
476     _RL vIce (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
477     C u/vIceRes :: residual of sea-ice momentum equations (output)
478     _RL uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
479     _RL vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
480    
481 mlosch 1.16 C !LOCAL VARIABLES:
482     C === Local variables ===
483 mlosch 1.15 C i,j,bi,bj :: loop indices
484     INTEGER i,j,bi,bj
485     INTEGER l
486     _RL resLoc, facLS
487     LOGICAL doLineSearch
488     C nVec :: size of the input vector(s)
489 jmc 1.20 C resTmp :: vector version of the residuals
490 mlosch 1.15 INTEGER nVec
491     PARAMETER ( nVec = 2*sNx*sNy )
492     _RL resTmp (nVec,1,nSx,nSy)
493 jmc 1.20
494 mlosch 1.15 CHARACTER*(MAX_LEN_MBUF) msgBuf
495     CEOP
496    
497     C Initialise some local variables
498     l = 0
499     resLoc = JFNKresidual
500     facLS = 1. _d 0
501     doLineSearch = .TRUE.
502     DO WHILE ( doLineSearch )
503     C Create update
504     DO bj=myByLo(myThid),myByHi(myThid)
505     DO bi=myBxLo(myThid),myBxHi(myThid)
506 jmc 1.20 DO J=1-OLy,sNy+OLy
507     DO I=1-OLx,sNx+OLx
508 mlosch 1.15 uIce(I,J,bi,bj) = uIce(I,J,bi,bj)+facLS*duIce(I,J,bi,bj)
509     vIce(I,J,bi,bj) = vIce(I,J,bi,bj)+facLS*dvIce(I,J,bi,bj)
510     ENDDO
511     ENDDO
512     ENDDO
513     ENDDO
514     C Compute current residual F(u), (includes re-computation of global
515     C variables DWATN, zeta, and eta, i.e. they are different after this)
516 jmc 1.20 CALL SEAICE_CALC_RESIDUAL(
517     I uIce, vIce,
518     O uIceRes, vIceRes,
519 mlosch 1.15 I newtonIter, 0, myTime, myIter, myThid )
520     C Important: Compute the norm of the residual using the same scalar
521     C product that SEAICE_FGMRES does
522     CALL SEAICE_MAP2VEC(nVec,uIceRes,vIceRes,resTmp,.TRUE.,myThid)
523     CALL SEAICE_SCALPROD(nVec,1,1,1,resTmp,resTmp,resLoc,myThid)
524     resLoc = SQRT(resLoc)
525 mlosch 1.19 C Determine, if we need more iterations
526 jmc 1.20 doLineSearch = resLoc .GE. JFNKresidual
527 mlosch 1.19 C Limit the maximum number of iterations arbitrarily to four
528 jmc 1.20 doLineSearch = doLineSearch .AND. l .LT. 4
529 mlosch 1.19 C For the first iteration du/vIce = 0 and there will be no
530     C improvement of the residual possible, so we do only the first
531     C iteration
532     IF ( newtonIter .EQ. 1 ) doLineSearch = .FALSE.
533     C Only start a linesearch after some Newton iterations
534     IF ( newtonIter .LE. SEAICE_JFNK_lsIter ) doLineSearch = .FALSE.
535     C Increment counter
536     l = l + 1
537 mlosch 1.15 C some output diagnostics
538     IF ( debugLevel.GE.debLevA .AND. doLineSearch ) THEN
539     _BEGIN_MASTER( myThid )
540 jmc 1.20 WRITE(msgBuf,'(2A,2(1XI6),3E12.5)')
541 mlosch 1.15 & ' S/R SEAICE_JFNK_UPDATE: Newton iter, LSiter, ',
542     & 'facLS, JFNKresidual, resLoc = ',
543     & newtonIter, l, facLS, JFNKresidual, resLoc
544     CALL PRINT_MESSAGE( msgBuf, standardMessageUnit,
545     & SQUEEZE_RIGHT, myThid )
546     _END_MASTER( myThid )
547     ENDIF
548     C Get ready for the next iteration: after adding du/vIce in the first
549     C iteration, we substract 0.5*du/vIce from u/vIce in the next
550     C iterations, 0.25*du/vIce in the second, etc.
551     facLS = - 0.5 _d 0 * ABS(facLS)
552     ENDDO
553     C This is the new residual
554     JFNKresidual = resLoc
555    
556 mlosch 1.21 #endif /* SEAICE_ALLOW_JFNK */
557 mlosch 1.1
558     RETURN
559     END

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