/[MITgcm]/MITgcm/pkg/exf/exf_interp.F
ViewVC logotype

Contents of /MITgcm/pkg/exf/exf_interp.F

Parent Directory Parent Directory | Revision Log Revision Log | View Revision Graph Revision Graph


Revision 1.12 - (show annotations) (download)
Fri Jan 13 16:48:03 2006 UTC (18 years, 8 months ago) by heimbach
Branch: MAIN
Changes since 1.11: +20 -1 lines
o Allow negative thetaMin and dont drown when crossing Greenwich
o Remaining clean up of thetaStar, saltStar from move to rbcs

1 #include "EXF_OPTIONS.h"
2 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 real*8 function lagran(i,x,a,sp)
13
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 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
44 implicit none
45
46 C infile = name of the input file (direct access binary)
47 C filePrec = file precicision (currently not used, assumes real*4)
48 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 C method = 1 for bilinear 2 for bicubic
56 C mythid = thread id
57 C
58
59 #include "SIZE.h"
60 #include "EEPARAMS.h"
61 #include "PARAMS.h"
62
63 C subroutine variables
64 character*(*) infile
65 integer filePrec, irecord, nx_in, ny_in
66 _RL arrayout(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
67 _RS xG_in (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
68 _RS yG (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
69 _RL lon_0, lon_inc
70 _RL lat_0, lat_inc(ny_in-1)
71 integer method, mythid
72
73 C local variables
74 real*8 ne_fac,nw_fac,se_fac,sw_fac
75 integer e_ind(snx,sny),w_ind(snx,sny)
76 integer n_ind(snx,sny),s_ind(snx,sny)
77 real*8 px_ind(4), py_ind(4), ew_val(4)
78 external lagran
79 real*8 lagran
80 real*4 arrayin(-1:nx_in+2 , -1:ny_in+2)
81 real*8 x_in (-1:nx_in+2), y_in(-1:ny_in+2)
82 integer i, j, k, l, js, bi, bj, sp, interp_unit
83 _RS xg(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
84
85 ! nomalize xg
86 do bj=myByLo(myThid),myByHi(myThid)
87 do bi=myBxLo(myThid),myBxHi(myThid)
88 do j=1-OLy,sNy+OLy
89 do i=1-OLx,sNx+OLx
90 xg(i,j,bi,bj) = xg_in(i,j,bi,bj)
91 xg(i,j,bi,bj) = mod(xg(i,j,bi,bj),360.)
92 if ( xg(i,j,bi,bj) .lt. 0. )
93 & xg(i,j,bi,bj) = 360.+xg(i,j,bi,bj)
94 enddo
95 enddo
96 enddo
97 enddo
98
99 call exf_interp_read(
100 I infile,
101 I filePrec,
102 O arrayin,
103 I irecord, xG, yG,
104 I lon_0, lon_inc,
105 I lat_0, lat_inc,
106 I nx_in, ny_in, method, mythid)
107 _BARRIER
108
109 C _BEGIN_MASTER( myThid )
110
111 C setup input grid
112 do i=-1,nx_in+2
113 x_in(i) = lon_0 + (i-1.)*lon_inc
114 x_in(i) = mod(x_in(i),360.)
115 if ( x_in(i) .lt. 0. )
116 & x_in(i) = 360.+x_in(i)
117 enddo
118
119 y_in(0) = lat_0 - lat_inc(1)
120 y_in(-1)= lat_0 - 2.*lat_inc(1)
121 y_in(1) = lat_0
122 do j=2,ny_in
123 y_in(j) = y_in(j-1) + lat_inc(j-1)
124 enddo
125 y_in(ny_in+1) = y_in(ny_in) + lat_inc(ny_in-1)
126 y_in(ny_in+2) = y_in(ny_in) + 2.*lat_inc(ny_in-1)
127
128 C enlarge boundary
129 do j=1,ny_in
130 arrayin(0,j) = arrayin(nx_in,j)
131 arrayin(-1,j) = arrayin(nx_in-1,j)
132 arrayin(nx_in+1,j) = arrayin(1,j)
133 arrayin(nx_in+2,j) = arrayin(2,j)
134 enddo
135 do i=-1,nx_in+2
136 arrayin(i,0) = arrayin(i,1)
137 arrayin(i,-1) = arrayin(i,1)
138 arrayin(i,ny_in+1) = arrayin(i,ny_in)
139 arrayin(i,ny_in+2) = arrayin(i,ny_in)
140 enddo
141
142 C _END_MASTER( myThid )
143
144 do bj = mybylo(mythid), mybyhi(mythid)
145 do bi = mybxlo(mythid), mybxhi(mythid)
146
147 C check validity of input/output coordinates
148 #ifdef ALLOW_DEBUG
149 if ( debugLevel .ge. debLevB ) then
150 do i=1,snx
151 do j=1,sny
152 if ( xG(i,j,bi,bj) .lt. x_in(0) .or.
153 & xG(i,j,bi,bj) .ge. x_in(nx_in+1) .or.
154 & yG(i,j,bi,bj) .lt. y_in(0) .or.
155 & yG(i,j,bi,bj) .ge. y_in(ny_in+1) ) then
156 print*,'ERROR in S/R EXF_INTERP:'
157 print*,' input grid must encompass output grid.'
158 print*,'i,j,bi,bj' ,i,j,bi,bj
159 print*,'xG,yG' ,xG(i,j,bi,bj),yG(i,j,bi,bj)
160 print*,'nx_in,ny_in' ,nx_in ,ny_in
161 print*,'x_in(0,nx_in+1)',x_in(0) ,x_in(nx_in+1)
162 print*,'y_in(0,ny_in+1)',y_in(0) ,y_in(ny_in+1)
163 STOP ' ABNORMAL END: S/R EXF_INTERP'
164 endif
165 enddo
166 enddo
167 endif
168 #endif /* ALLOW_DEBUG */
169
170 C compute interpolation indices
171 do i=1,snx
172 do j=1,sny
173 if (xG(i,j,bi,bj)-x_in(1) .ge. 0.) then
174 w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc) + 1
175 else
176 w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc)
177 endif
178 e_ind(i,j) = w_ind(i,j) + 1
179 js = ny_in*.5
180 do while (yG(i,j,bi,bj) .lt. y_in(js))
181 js = (js - 1)*.5
182 enddo
183 do while (yG(i,j,bi,bj) .ge. y_in(js+1))
184 js = js + 1
185 enddo
186 s_ind(i,j) = js
187 n_ind(i,j) = js + 1
188 enddo
189 enddo
190
191 if (method .eq. 1) then
192
193 C bilinear interpolation
194 sp = 2
195 do j=1,sny
196 do i=1,snx
197 arrayout(i,j,bi,bj) = 0.
198 do l=0,1
199 px_ind(l+1) = x_in(w_ind(i,j)+l)
200 py_ind(l+1) = y_in(s_ind(i,j)+l)
201 enddo
202 do k=1,2
203 ew_val(k) = arrayin(w_ind(i,j),s_ind(i,j)+k-1)
204 & *lagran(1,xG(i,j,bi,bj),px_ind,sp)
205 & +arrayin(e_ind(i,j),s_ind(i,j)+k-1)
206 & *lagran(2,xG(i,j,bi,bj),px_ind,sp)
207 arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
208 & +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
209 enddo
210 enddo
211 enddo
212 elseif (method .eq. 2) then
213
214 C bicubic interpolation
215 sp = 4
216 do j=1,sny
217 do i=1,snx
218 arrayout(i,j,bi,bj) = 0.
219 do l=-1,2
220 px_ind(l+2) = x_in(w_ind(i,j)+l)
221 py_ind(l+2) = y_in(s_ind(i,j)+l)
222 enddo
223 do k=1,4
224 ew_val(k) =
225 & arrayin(w_ind(i,j)-1,s_ind(i,j)+k-2)
226 & *lagran(1,xG(i,j,bi,bj),px_ind,sp)
227 & +arrayin(w_ind(i,j) ,s_ind(i,j)+k-2)
228 & *lagran(2,xG(i,j,bi,bj),px_ind,sp)
229 & +arrayin(e_ind(i,j) ,s_ind(i,j)+k-2)
230 & *lagran(3,xG(i,j,bi,bj),px_ind,sp)
231 & +arrayin(e_ind(i,j)+1,s_ind(i,j)+k-2)
232 & *lagran(4,xG(i,j,bi,bj),px_ind,sp)
233 arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
234 & +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
235 enddo
236 enddo
237 enddo
238 else
239 stop 'stop in exf_interp.F: interpolation method not supported'
240 endif
241 enddo
242 enddo
243
244 END

  ViewVC Help
Powered by ViewVC 1.1.22