/[MITgcm]/MITgcm/pkg/seaice/seaice_jacvec.F
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Contents of /MITgcm/pkg/seaice/seaice_jacvec.F

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Revision 1.2 - (show annotations) (download)
Tue Nov 6 13:09:30 2012 UTC (12 years, 8 months ago) by mlosch
Branch: MAIN
Changes since 1.1: +46 -2 lines
add instructions to use TAF to generate jacobian-times-vector code and
replace finite-difference code with it

1 C $Header: /u/gcmpack/MITgcm/pkg/seaice/seaice_jacvec.F,v 1.1 2012/10/16 07:00:21 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 #if ( defined (SEAICE_CGRID) && \
60 defined (SEAICE_ALLOW_JFNK) && \
61 defined (SEAICE_ALLOW_DYNAMICS) )
62 C Local variables:
63 _RL utp (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
64 _RL vtp (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
65 C u/vIceResP :: residual computed with u/vtp
66 _RL uIceResP(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
67 _RL vIceResP(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
68
69 C i,j,bi,bj :: loop indices
70 INTEGER i,j,bi,bj
71 _RL epsilon, reps
72 CEOP
73 C Instructions for using TAF or TAMC to generate exact Jacobian times
74 C vector operations:
75 C
76 C 1. make small_f
77 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
78 C 3. staf -v1 -forward -toplevel seaice_calc_residual -input uIceLoc,viceLoc -output uIceRes,vIceRes taf_input.f
79 C 4. insert content of taf_input_ftl.f at the end of this file
80 C 5. add the following code and comment out the finite difference code
81 CML _RL g_duIce(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
82 CML _RL g_dvIce(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
83 CML _RL g_uIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
84 CML _RL g_vIceRes(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
85 CML
86 CML IF (.false.) then
87 CMLC Initialise
88 CML DO bj=myByLo(myThid),myByHi(myThid)
89 CML DO bi=myBxLo(myThid),myBxHi(myThid)
90 CML DO J=1-Oly,sNy+Oly
91 CML DO I=1-Olx,sNx+Olx
92 CML g_duIce(I,J,bi,bj) = duice(I,J,bi,bj)
93 CML g_dvIce(I,J,bi,bj) = dvice(I,J,bi,bj)
94 CML g_uIceRes(I,J,bi,bj) = 0. _d 0
95 CML g_vIceRes(I,J,bi,bj) = 0. _d 0
96 CML uIceResP(I,J,bi,bj) = 0. _d 0
97 CML vIceResP(I,J,bi,bj) = 0. _d 0
98 CML ENDDO
99 CML ENDDO
100 CML ENDDO
101 CML ENDDO
102 CML
103 CML CALL G_SEAICE_CALC_RESIDUAL( uIce, g_duice, vIce,
104 CML $g_dvice, uiceresp, g_uiceres, viceresp, g_viceres, newtoniter,
105 CML $kryloviter, mytime, myiter, mythid )
106 CML
107 CML DO bj=myByLo(myThid),myByHi(myThid)
108 CML DO bi=myBxLo(myThid),myBxHi(myThid)
109 CML DO J=1-Oly,sNy+Oly
110 CML DO I=1-Olx,sNx+Olx
111 CML duice(I,J,bi,bj)=g_uiceres(I,J,bi,bj)
112 CML dvice(I,J,bi,bj)=g_viceres(I,J,bi,bj)
113 CML ENDDO
114 CML ENDDO
115 CML ENDDO
116 CML ENDDO
117
118 C Initialise
119 epsilon = 1. _d -06
120 reps = 1. _d 0/epsilon
121
122 DO bj=myByLo(myThid),myByHi(myThid)
123 DO bi=myBxLo(myThid),myBxHi(myThid)
124 DO J=1-Oly,sNy+Oly
125 DO I=1-Olx,sNx+Olx
126 utp(I,J,bi,bj) = uIce(I,J,bi,bj) + epsilon * duIce(I,J,bi,bj)
127 vtp(I,J,bi,bj) = vIce(I,J,bi,bj) + epsilon * dvIce(I,J,bi,bj)
128 ENDDO
129 ENDDO
130 ENDDO
131 ENDDO
132
133 C Compute new residual F(u)
134 CALL SEAICE_CALC_RESIDUAL(
135 I utp, vtp,
136 O uIceResP, vIceResP,
137 I newtonIter, krylovIter, myTime, myIter, myThid )
138
139 C approximate Jacobian times vector by one-sided finite differences
140 C and store in du/vIce
141 DO bj = myByLo(myThid),myByHi(myThid)
142 DO bi = myBxLo(myThid),myBxHi(myThid)
143 DO I = 1, sNx
144 DO J = 1, sNy
145 duIce(I,J,bi,bj) =
146 & (uIceResP(I,J,bi,bj)-uIceRes(I,J,bi,bj))*reps
147 dvIce(I,J,bi,bj) =
148 & (vIceResP(I,J,bi,bj)-vIceRes(I,J,bi,bj))*reps
149 ENDDO
150 ENDDO
151 ENDDO
152 ENDDO
153
154 #endif /* SEAICE_ALLOW_DYNAMICS and SEAICE_CGRID and SEAICE_ALLOW_JFNK */
155
156 RETURN
157 END

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