/[MITgcm]/MITgcm/model/src/ini_cg2d.F
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Revision 1.35 - (hide annotations) (download)
Thu Jun 7 15:53:21 2001 UTC (22 years, 11 months ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint40pre1
Changes since 1.34: +3 -3 lines
Changed a write(0,...) to a write(*,...)

1 adcroft 1.35 C $Header: /u/gcmpack/models/MITgcmUV/model/src/ini_cg2d.F,v 1.34 2001/05/29 14:01:37 adcroft Exp $
2 jmc 1.30 C $Name: $
3 cnh 1.1
4 adcroft 1.13 #include "CPP_OPTIONS.h"
5 cnh 1.1
6     SUBROUTINE INI_CG2D( myThid )
7     C /==========================================================\
8     C | SUBROUTINE INI_CG2D |
9     C | o Initialise 2d conjugate gradient solver operators. |
10     C |==========================================================|
11     C | These arrays are purely a function of the basin geom. |
12     C | We set then here once and them use then repeatedly. |
13     C \==========================================================/
14 adcroft 1.23 IMPLICIT NONE
15 cnh 1.1
16     C === Global variables ===
17     #include "SIZE.h"
18     #include "EEPARAMS.h"
19     #include "PARAMS.h"
20     #include "GRID.h"
21 adcroft 1.34 c#include "DYNVARS.h"
22 jmc 1.31 #include "SURFACE.h"
23 adcroft 1.34 #include "CG2D.h"
24 adcroft 1.26 #ifdef ALLOW_OBCS
25 adcroft 1.22 #include "OBCS.h"
26 adcroft 1.26 #endif
27 cnh 1.1
28     C === Routine arguments ===
29     C myThid - Thread no. that called this routine.
30     INTEGER myThid
31    
32     C === Local variables ===
33     C xG, yG - Global coordinate location.
34     C zG
35     C iG, jG - Global coordinate index
36     C bi,bj - Loop counters
37     C faceArea - Temporary used to hold cell face areas.
38     C I,J,K
39 adcroft 1.34 C myNorm - Work variable used in calculating normalisation factor
40     C sumArea - Work variable used to compute the total Domain Area
41 cnh 1.1 CHARACTER*(MAX_LEN_MBUF) msgBuf
42     INTEGER bi, bj
43     INTEGER I, J, K
44 cnh 1.7 _RL faceArea
45 cnh 1.15 _RS myNorm
46 adcroft 1.34 _RL sumArea
47 cnh 1.4 _RL aC, aCw, aCs
48 cnh 1.1
49 jmc 1.31 C-- Initialise -Boyancy at surface level : Bo_surf
50     C Bo_surf is defined as d/dr(Phi_surf) and set to g/rtoz (linear free surface)
51     C with rtoz = conversion factor from r-unit to z-unit (=horiVertRatio)
52     C an acurate formulation will include P_surf and T,S_surf effects on rho_surf:
53     C z-ocean (rtoz=1) : Bo_surf = - Boyancy = gravity * rho_surf/rho_0
54     C p-atmos (rtoz=rho_c*g) : Bo_surf = (1/rho)_surf
55     C--
56     IF ( buoyancyRelation .EQ. 'ATMOSPHERIC' ) THEN
57     DO bj=myByLo(myThid),myByHi(myThid)
58     DO bi=myBxLo(myThid),myBxHi(myThid)
59     DO J=1-Oly,sNy+Oly
60     DO I=1-Olx,sNx+Olx
61     Bo_surf(I,J,bi,bj) = recip_rhoConst
62     recip_Bo(I,J,bi,bj) = rhoConst
63     ENDDO
64     ENDDO
65     ENDDO
66     ENDDO
67     ELSE
68 jmc 1.33 C- gBaro = gravity (except for External mode test with reduced gravity)
69 jmc 1.31 DO bj=myByLo(myThid),myByHi(myThid)
70     DO bi=myBxLo(myThid),myBxHi(myThid)
71     DO J=1-Oly,sNy+Oly
72     DO I=1-Olx,sNx+Olx
73 jmc 1.33 Bo_surf(I,J,bi,bj) = gBaro
74     recip_Bo(I,J,bi,bj) = 1. _d 0 / gBaro
75 jmc 1.31 ENDDO
76     ENDDO
77     ENDDO
78     ENDDO
79     ENDIF
80    
81     C-- Update overlap regions
82     _EXCH_XY_R8(Bo_surf, myThid)
83     _EXCH_XY_R8(recip_Bo, myThid)
84    
85 cnh 1.1 C-- Initialise laplace operator
86     C aW2d: integral in Z Ax/dX
87     C aS2d: integral in Z Ay/dY
88     myNorm = 0. _d 0
89     DO bj=myByLo(myThid),myByHi(myThid)
90     DO bi=myBxLo(myThid),myBxHi(myThid)
91     DO J=1,sNy
92     DO I=1,sNx
93     aW2d(I,J,bi,bj) = 0. _d 0
94     aS2d(I,J,bi,bj) = 0. _d 0
95     ENDDO
96     ENDDO
97 cnh 1.17 DO K=1,Nr
98 cnh 1.1 DO J=1,sNy
99     DO I=1,sNx
100 cnh 1.20 faceArea = _dyG(I,J,bi,bj)*drF(K)
101     & *_hFacW(I,J,K,bi,bj)
102 cnh 1.1 aW2d(I,J,bi,bj) = aW2d(I,J,bi,bj) +
103 jmc 1.32 & implicSurfPress*implicDiv2DFlow
104     & *faceArea*recip_dxC(I,J,bi,bj)
105 cnh 1.20 faceArea = _dxG(I,J,bi,bj)*drF(K)
106     & *_hFacS(I,J,K,bi,bj)
107 cnh 1.1 aS2d(I,J,bi,bj) = aS2d(I,J,bi,bj) +
108 jmc 1.32 & implicSurfPress*implicDiv2DFlow
109     & *faceArea*recip_dyC(I,J,bi,bj)
110 cnh 1.1 ENDDO
111     ENDDO
112     ENDDO
113 adcroft 1.26 #ifdef ALLOW_OBCS
114 adcroft 1.28 IF (useOBCS) THEN
115 adcroft 1.22 DO I=1,sNx
116     IF (OB_Jn(I,bi,bj).NE.0) aS2d(I,OB_Jn(I,bi,bj),bi,bj)=0.
117     IF (OB_Jn(I,bi,bj).NE.0) aS2d(I,OB_Jn(I,bi,bj)+1,bi,bj)=0.
118     IF (OB_Js(I,bi,bj).NE.0) aS2d(I,OB_Js(I,bi,bj)+1,bi,bj)=0.
119     IF (OB_Js(I,bi,bj).NE.0) aS2d(I,OB_Js(I,bi,bj),bi,bj)=0.
120     ENDDO
121     DO J=1,sNy
122     IF (OB_Ie(J,bi,bj).NE.0) aW2d(OB_Ie(J,bi,bj),J,bi,bj)=0.
123     IF (OB_Ie(J,bi,bj).NE.0) aW2d(OB_Ie(J,bi,bj)+1,J,bi,bj)=0.
124     IF (OB_Iw(J,bi,bj).NE.0) aW2d(OB_Iw(J,bi,bj)+1,J,bi,bj)=0.
125     IF (OB_Iw(J,bi,bj).NE.0) aW2d(OB_Iw(J,bi,bj),J,bi,bj)=0.
126     ENDDO
127     ENDIF
128 adcroft 1.26 #endif
129 cnh 1.1 DO J=1,sNy
130     DO I=1,sNx
131     myNorm = MAX(ABS(aW2d(I,J,bi,bj)),myNorm)
132     myNorm = MAX(ABS(aS2d(I,J,bi,bj)),myNorm)
133     ENDDO
134     ENDDO
135     ENDDO
136     ENDDO
137 adcroft 1.25 _GLOBAL_MAX_R4( myNorm, myThid )
138     IF ( myNorm .NE. 0. _d 0 ) THEN
139     myNorm = 1. _d 0/myNorm
140 cnh 1.1 ELSE
141     myNorm = 1. _d 0
142     ENDIF
143 cnh 1.5 cg2dNorm = myNorm
144 cnh 1.1 _BEGIN_MASTER( myThid )
145     CcnhDebugStarts
146 cnh 1.20 WRITE(msgBuf,'(A,E40.25)') '// CG2D normalisation factor = ',
147     & cg2dNorm
148 cnh 1.3 CALL PRINT_MESSAGE( msgBuf,standardMessageUnit,SQUEEZE_RIGHT,1)
149     WRITE(msgBuf,*) ' '
150 cnh 1.1 CALL PRINT_MESSAGE( msgBuf,standardMessageUnit,SQUEEZE_RIGHT,1)
151     CcnhDebugEnds
152     _END_MASTER( myThid )
153     DO bj=myByLo(myThid),myByHi(myThid)
154     DO bi=myBxLo(myThid),myBxHi(myThid)
155     DO J=1,sNy
156     DO I=1,sNx
157     aW2d(I,J,bi,bj) = aW2d(I,J,bi,bj)*myNorm
158     aS2d(I,J,bi,bj) = aS2d(I,J,bi,bj)*myNorm
159     ENDDO
160     ENDDO
161     ENDDO
162     ENDDO
163    
164     C-- Update overlap regions
165     CcnhDebugStarts
166 cnh 1.14 C CALL PLOT_FIELD_XYRS( aW2d, 'AW2D INI_CG2D.1' , 1, myThid )
167     C CALL PLOT_FIELD_XYRS( aS2d, 'AS2D INI_CG2D.1' , 1, myThid )
168 cnh 1.1 CcnhDebugEnds
169 adcroft 1.34 c _EXCH_XY_R4(aW2d, myThid)
170     c _EXCH_XY_R4(aS2d, myThid)
171     CALL EXCH_UV_XY_RS(aW2d,aS2d,.FALSE.,myThid)
172 cnh 1.1 CcnhDebugStarts
173 adcroft 1.24 C CALL PLOT_FIELD_XYRS( aW2d, 'AW2D INI_CG2D.2' , 1, myThid )
174     C CALL PLOT_FIELD_XYRS( aS2d, 'AS2D INI_CG2D.2' , 1, myThid )
175 cnh 1.1 CcnhDebugEnds
176    
177 adcroft 1.34 C-- Define the solver tolerance in the appropriate Unit :
178     cg2dNormaliseRHS = cg2dTargetResWunit.LE.0
179     IF (cg2dNormaliseRHS) THEN
180     C- when using a normalisation of RHS, tolerance has no unit => no conversion
181     cg2dTolerance = cg2dTargetResidual
182     ELSE
183     C- compute the total Area of the domain :
184     sumArea = 0.
185     DO bj=myByLo(myThid),myByHi(myThid)
186     DO bi=myBxLo(myThid),myBxHi(myThid)
187     DO j=1,sNy
188     DO i=1,sNx
189     IF (Ro_surf(i,j,bi,bj).GT.R_low(i,j,bi,bj)) THEN
190     sumArea = sumArea + rA(i,j,bi,bj)
191     ENDIF
192     ENDDO
193     ENDDO
194     ENDDO
195     ENDDO
196 adcroft 1.35 c WRITE(*,*) ' mythid, sumArea = ', mythid, sumArea
197 adcroft 1.34 _GLOBAL_SUM_R8( sumArea, myThid )
198     C- convert Target-Residual (in W unit) to cg2d-solver residual unit [m^2/s^2]
199     cg2dTolerance = cg2dNorm * cg2dTargetResWunit
200     & * sumArea / deltaTMom
201 adcroft 1.35 WRITE(*,'(2A,1P2E22.14)') ' ini_cg2d: ',
202 adcroft 1.34 & 'sumArea,cg2dTolerance =', sumArea,cg2dTolerance
203     ENDIF
204    
205 cnh 1.1 C-- Initialise preconditioner
206 cnh 1.4 C Note. 20th May 1998
207     C I made a weird discovery! In the model paper we argue
208     C for the form of the preconditioner used here ( see
209     C A Finite-volume, Incompressible Navier-Stokes Model
210     C ...., Marshall et. al ). The algebra gives a simple
211     C 0.5 factor for the averaging of ac and aCw to get a
212     C symmettric pre-conditioner. By using a factor of 0.51
213     C i.e. scaling the off-diagonal terms in the
214     C preconditioner down slightly I managed to get the
215     C number of iterations for convergence in a test case to
216     C drop form 192 -> 134! Need to investigate this further!
217     C For now I have introduced a parameter cg2dpcOffDFac which
218     C defaults to 0.51 but can be set at runtime.
219 cnh 1.1 DO bj=myByLo(myThid),myByHi(myThid)
220     DO bi=myBxLo(myThid),myBxHi(myThid)
221     DO J=1,sNy
222     DO I=1,sNx
223     pC(I,J,bi,bj) = 1. _d 0
224 cnh 1.4 aC = -(
225     & aW2d(I,J,bi,bj) + aW2d(I+1,J ,bi,bj)
226 adcroft 1.24 & +aS2d(I,J,bi,bj) + aS2d(I ,J+1,bi,bj)
227 jmc 1.32 & +freeSurfFac*myNorm*recip_Bo(I,J,bi,bj)*
228 cnh 1.17 & rA(I,J,bi,bj)/deltaTMom/deltaTMom
229 cnh 1.4 & )
230     aCs = -(
231     & aW2d(I,J-1,bi,bj) + aW2d(I+1,J-1,bi,bj)
232     & +aS2d(I,J-1,bi,bj) + aS2d(I ,J ,bi,bj)
233 jmc 1.32 & +freeSurfFac*myNorm*recip_Bo(I,J-1,bi,bj)*
234 cnh 1.17 & rA(I,J-1,bi,bj)/deltaTMom/deltaTMom
235 cnh 1.4 & )
236     aCw = -(
237     & aW2d(I-1,J,bi,bj) + aW2d(I ,J ,bi,bj)
238     & +aS2d(I-1,J,bi,bj) + aS2d(I-1,J+1,bi,bj)
239 jmc 1.32 & +freeSurfFac*myNorm*recip_Bo(I-1,J,bi,bj)*
240 cnh 1.17 & rA(I-1,J,bi,bj)/deltaTMom/deltaTMom
241 cnh 1.4 & )
242     IF ( aC .EQ. 0. ) THEN
243 adcroft 1.27 pC(I,J,bi,bj) = 1. _d 0
244 cnh 1.4 ELSE
245     pC(I,J,bi,bj) = 1. _d 0 / aC
246     ENDIF
247     IF ( aC + aCw .EQ. 0. ) THEN
248     pW(I,J,bi,bj) = 0.
249     ELSE
250     pW(I,J,bi,bj) =
251     & -aW2d(I ,J ,bi,bj)/((cg2dpcOffDFac *(aCw+aC))**2 )
252     ENDIF
253     IF ( aC + aCs .EQ. 0. ) THEN
254     pS(I,J,bi,bj) = 0.
255     ELSE
256     pS(I,J,bi,bj) =
257     & -aS2d(I ,J ,bi,bj)/((cg2dpcOffDFac *(aCs+aC))**2 )
258     ENDIF
259 cnh 1.6 C pC(I,J,bi,bj) = 1.
260     C pW(I,J,bi,bj) = 0.
261     C pS(I,J,bi,bj) = 0.
262 cnh 1.1 ENDDO
263     ENDDO
264     ENDDO
265     ENDDO
266     C-- Update overlap regions
267     _EXCH_XY_R4(pC, myThid)
268 adcroft 1.34 c _EXCH_XY_R4(pW, myThid)
269     c _EXCH_XY_R4(pS, myThid)
270     CALL EXCH_UV_XY_RS(pW,pS,.FALSE.,myThid)
271 cnh 1.18 CcnhDebugStarts
272 adcroft 1.24 C CALL PLOT_FIELD_XYRS( pC, 'pC INI_CG2D.2' , 1, myThid )
273     C CALL PLOT_FIELD_XYRS( pW, 'pW INI_CG2D.2' , 1, myThid )
274     C CALL PLOT_FIELD_XYRS( pS, 'pS INI_CG2D.2' , 1, myThid )
275 cnh 1.18 CcnhDebugEnds
276 cnh 1.1
277     RETURN
278     END

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