/[MITgcm]/MITgcm/pkg/exf/exf_interp.F
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Revision 1.4 - (hide annotations) (download)
Sun Dec 7 07:41:45 2003 UTC (20 years, 6 months ago) by dimitri
Branch: MAIN
Changes since 1.3: +75 -34 lines
adding single-cpu input capability

1 edhill 1.3 #include "EXF_OPTIONS.h"
2 dimitri 1.1 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
3     C Flux Coupler using C
4     C Bilinear interpolation of forcing fields C
5     C C
6     C B. Cheng (12/2002) C
7     C C
8     C added Bicubic (bnc 1/2003) C
9     C C
10     CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
11    
12 dimitri 1.2 real*8 function lagran(i,x,a,sp)
13 dimitri 1.1
14     INTEGER i,k,sp
15     _RS x
16     real*8 a(4)
17     real*8 numer,denom
18    
19     numer = 1.D0
20     denom = 1.D0
21    
22     do k=1,sp
23     if ( k .ne. i) then
24     denom = denom*(a(i) - a(k))
25     numer = numer*(x - a(k))
26     endif
27     enddo
28    
29     lagran = numer/denom
30    
31     return
32     end
33    
34    
35     SUBROUTINE exf_interp(
36     I infile,
37     I filePrec,
38     O arrayout,
39 dimitri 1.2 I irecord, xG, yG,
40     I lon_0, lon_inc,
41     I lat_0, lat_inc,
42     I nx_in, ny_in, method, mythid)
43 dimitri 1.1
44 dimitri 1.4 implicit none
45    
46 dimitri 1.2 C infile = name of the input file (direct access binary)
47     C filePrec = file precicision (currently not used, assumes real*4)
48 dimitri 1.1 C arrout = output arrays (different for each processor)
49     C irecord = record number in global file
50     C xG,yG = coordinates for output grid
51     C lon_0, lat_0 = lon and lat of sw corner of global input grid
52     C lon_inc = scalar x-grid increment
53     C lat_inc = vector y-grid increments
54     C nx_in, ny_in = input x-grid and y-grid size
55 dimitri 1.2 C method = 1 for bilinear 2 for bicubic
56     C mythid = thread id
57 dimitri 1.1 C
58    
59     #include "SIZE.h"
60     #include "EEPARAMS.h"
61 dimitri 1.4 #ifdef ALLOW_USE_MPI
62     # include "EESUPPORT.h"
63     # include "PARAMS.h"
64     #endif /* ALLOW_USE_MPI */
65 dimitri 1.2
66     C subroutine variables
67     character*(*) infile
68     integer filePrec, irecord, nx_in, ny_in
69     _RL arrayout(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
70     _RS xG (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
71     _RS yG (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
72     _RL lon_0, lon_inc
73     _RL lat_0, lat_inc(ny_in-1)
74     integer method, mythid
75 dimitri 1.1
76     C local variables
77 dimitri 1.2 integer ierr
78     real*8 ne_fac,nw_fac,se_fac,sw_fac
79     integer e_ind(snx),w_ind(snx)
80     integer n_ind(sny),s_ind(sny)
81     real*8 px_ind(4), py_ind(4), ew_val(4)
82 dimitri 1.1 external lagran
83 dimitri 1.2 real*8 lagran
84     real*4 arrayin(-1:nx_in+2 , -1:ny_in+2)
85     real*8 x_in (-1:nx_in+2), y_in(-1:ny_in+2)
86 dimitri 1.4 integer i, j, k, l, js, bi, bj, interp_unit, sp
87     real*4 global(nx_in,ny_in)
88    
89     _BEGIN_MASTER( myThid )
90 dimitri 1.2
91     C check input arguments
92 dimitri 1.4 if ( .NOT. (filePrec .EQ. 32) )
93     & stop 'stop in exf_interp.F: value of filePrec not allowed'
94 dimitri 1.1
95     C read in input data
96 dimitri 1.4 #ifdef ALLOW_USE_MPI
97     if (useSingleCPUIO) then
98    
99     C master thread of process 0, only, opens a global file
100     IF( mpiMyId .EQ. 0 ) THEN
101     call mdsfindunit( interp_unit, mythid)
102     open(interp_unit,file=infile,status='old',access='direct',
103     & recl=nx_in*ny_in*4)
104     read(interp_unit,rec=irecord)
105     & ((global(i,j),i=1,nx_in),j=1,ny_in)
106     close(interp_unit)
107     ENDIF
108    
109     C broadcast to all processes
110     call MPI_BCAST(global,nx_in*ny_in,MPI_REAL,
111     & 0,MPI_COMM_MODEL,ierr)
112     do j=1,ny_in
113     do i=1,nx_in
114     arrayin(i,j)=global(i,j)
115     enddo
116     enddo
117    
118     else
119     #endif /* ALLOW_USE_MPI */
120    
121     call mdsfindunit( interp_unit, mythid)
122     open(interp_unit,file=infile,status='old',access='direct',
123     & recl=nx_in*ny_in*4)
124     read(interp_unit,rec=irecord)
125     & ((arrayin(i,j),i=1,nx_in),j=1,ny_in)
126     close(interp_unit)
127    
128     #ifdef ALLOW_USE_MPI
129     endif
130     #endif /* ALLOW_USE_MPI */
131    
132 dimitri 1.1 #ifdef _BYTESWAPIO
133 dimitri 1.4 call MDS_BYTESWAPR4((nx_in+4)*(ny_in+4), arrayin )
134     #endif /* _BYTESWAPIO */
135 dimitri 1.1
136     C setup input grid
137 dimitri 1.4 do i=-1,nx_in+2
138     x_in(i) = lon_0 + (i-1.)*lon_inc
139     enddo
140     y_in(0) = lat_0 - lat_inc(1)
141     y_in(-1)= lat_0 - 2.*lat_inc(1)
142     y_in(1) = lat_0
143     do j=2,ny_in
144     y_in(j) = y_in(j-1) + lat_inc(j-1)
145     enddo
146     y_in(ny_in+1) = y_in(ny_in) + lat_inc(ny_in-1)
147     y_in(ny_in+2) = y_in(ny_in) + 2.*lat_inc(ny_in-1)
148 dimitri 1.1
149     C enlarge boundary
150 dimitri 1.4 do j=1,ny_in
151     arrayin(0,j) = arrayin(nx_in,j)
152     arrayin(-1,j) = arrayin(nx_in-1,j)
153     arrayin(nx_in+1,j) = arrayin(1,j)
154     arrayin(nx_in+2,j) = arrayin(2,j)
155     enddo
156     do i=-1,nx_in+2
157     arrayin(i,0) = arrayin(i,1)
158     arrayin(i,-1) = arrayin(i,1)
159     arrayin(i,ny_in+1) = arrayin(i,ny_in)
160     arrayin(i,ny_in+2) = arrayin(i,ny_in)
161     enddo
162    
163     _END_MASTER( myThid )
164 dimitri 1.2
165     do bj = mybylo(mythid), mybyhi(mythid)
166     do bi = mybxlo(mythid), mybxhi(mythid)
167    
168     C check validity of input/output coordinates
169     if ( xG(1,1 ,bi,bj) .le. x_in(0) .or.
170     & xG(snx,1,bi,bj) .ge. x_in(nx_in+1) .or.
171     & yG(1,1 ,bi,bj) .lt. y_in(1) .or.
172     & yG(1,sny,bi,bj) .gt. y_in(ny_in) ) then
173     print*,'ERROR in S/R EXF_INTERP:'
174     print*,' input grid must encompass output grid.'
175     STOP ' ABNORMAL END: S/R EXF_INTERP'
176     endif
177 dimitri 1.1
178     C compute interpolation indices
179     do i=1,snx
180 dimitri 1.2 if (xG(i,1,bi,bj)-x_in(1) .ge. 0.) then
181     w_ind(i) = int((xG(i,1,bi,bj)-x_in(1))/lon_inc) + 1
182     else
183     w_ind(i) = int((xG(i,1,bi,bj)-x_in(1))/lon_inc)
184     endif
185     e_ind(i) = w_ind(i) + 1
186 dimitri 1.1 enddo
187     js = ny_in/2
188     do j=1,sny
189 dimitri 1.2 do while (yG(1,j,bi,bj) .lt. y_in(js))
190     js = (js + 1)/2
191     enddo
192     do while (yG(1,j,bi,bj) .ge. y_in(js+1))
193     js = js + 1
194     enddo
195     s_ind(j) = js
196     n_ind(j) = js + 1
197 dimitri 1.1 enddo
198    
199 dimitri 1.2 if (method .eq. 1) then
200 dimitri 1.1
201 dimitri 1.2 C bilinear interpolation
202     sp = 2
203     do j=1,sny
204     do i=1,snx
205 dimitri 1.1 arrayout(i,j,bi,bj) = 0.
206 dimitri 1.2 do l=0,1
207     px_ind(l+1) = x_in(w_ind(i)+l)
208     py_ind(l+1) = y_in(s_ind(j)+l)
209 dimitri 1.1 enddo
210 dimitri 1.2 do k=1,2
211     ew_val(k) = arrayin(w_ind(i),s_ind(j)+k-1)
212     & *lagran(1,xG(i,1,bi,bj),px_ind,sp)
213     & +arrayin(e_ind(i),s_ind(j)+k-1)
214     & *lagran(2,xG(i,1,bi,bj),px_ind,sp)
215     arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
216     & +ew_val(k)*lagran(k,yG(1,j,bi,bj),py_ind,sp)
217 dimitri 1.1 enddo
218     enddo
219     enddo
220 dimitri 1.2 elseif (method .eq. 2) then
221 dimitri 1.1
222 dimitri 1.2 C bicubic interpolation
223     sp = 4
224     do j=1,sny
225     do i=1,snx
226 dimitri 1.1 arrayout(i,j,bi,bj) = 0.
227 dimitri 1.2 do l=-1,2
228     px_ind(l+2) = x_in(w_ind(i)+l)
229     py_ind(l+2) = y_in(s_ind(j)+l)
230 dimitri 1.1 enddo
231 dimitri 1.2 do k=1,4
232     ew_val(k) =
233     & arrayin(w_ind(i)-1,s_ind(j)+k-2)
234     & *lagran(1,xG(i,1,bi,bj),px_ind,sp)
235     & +arrayin(w_ind(i) ,s_ind(j)+k-2)
236     & *lagran(2,xG(i,1,bi,bj),px_ind,sp)
237     & +arrayin(e_ind(i) ,s_ind(j)+k-2)
238     & *lagran(3,xG(i,1,bi,bj),px_ind,sp)
239     & +arrayin(e_ind(i)+1,s_ind(j)+k-2)
240     & *lagran(4,xG(i,1,bi,bj),px_ind,sp)
241     arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
242     & +ew_val(k)*lagran(k,yG(1,j,bi,bj),py_ind,sp)
243 dimitri 1.1 enddo
244 dimitri 1.2 enddo
245 dimitri 1.1 enddo
246 dimitri 1.2 else
247     stop 'stop in exf_interp.F: interpolation method not supported'
248     endif
249     enddo
250     enddo
251 dimitri 1.1
252     END

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