pkg/exf/exf_interp.F

#include "EXF_OPTIONS.h"
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
C Flux Coupler using                       C
C Bilinear interpolation of forcing fields C
C                                          C
C B. Cheng (12/2002)                       C
C                                          C
C added Bicubic (bnc 1/2003)               C
C                                          C
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

        real*8 function lagran(i,x,a,sp)

        INTEGER i,k,sp
        _RS x
        real*8 a(4)
        real*8 numer,denom

        numer = 1.D0
        denom = 1.D0

        do k=1,sp
        if ( k .ne. i) then
          denom = denom*(a(i) - a(k))
          numer = numer*(x    - a(k))
        endif
        enddo

        lagran = numer/denom

        return
        end


       SUBROUTINE exf_interp(
     I   infile,
     I   filePrec,
     O   arrayout,
     I   irecord, xG_in, yG,
     I   lon_0, lon_inc,
     I   lat_0, lat_inc,
     I   nx_in, ny_in, method, mythid)

      implicit none

C     infile       = name of the input file (direct access binary)
C     filePrec     = file precicision (currently not used, assumes real*4)
C     arrout       = output arrays (different for each processor)
C     irecord      = record number in global file
C     xG,yG        = coordinates for output grid
C     lon_0, lat_0 = lon and lat of sw corner of global input grid
C     lon_inc      = scalar x-grid increment
C     lat_inc      = vector y-grid increments
C     nx_in, ny_in = input x-grid and y-grid size
C     method       = 1,11,21 for bilinear; 2,12,22 for bicubic
C                    1,2 for tracer; 11,12 for U; 21,22 for V
C     mythid       = thread id
C

#include "SIZE.h"
#include "EEPARAMS.h"
#include "PARAMS.h"

C subroutine variables
      character*(*) infile
      integer       filePrec, irecord, nx_in, ny_in
      _RL           arrayout(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
      _RS           xG_in      (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
      _RS           yG      (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
      _RL           lon_0, lon_inc
      _RL           lat_0, lat_inc(ny_in-1)
      integer       method, mythid

C local variables
      integer  e_ind(snx,sny),w_ind(snx,sny)
      integer  n_ind(snx,sny),s_ind(snx,sny)
      real*8   px_ind(4), py_ind(4), ew_val(4)
      external lagran
      real*8   lagran
      real*4   arrayin(-1:nx_in+2 ,      -1:ny_in+2)
      real*8   x_in   (-1:nx_in+2), y_in(-1:ny_in+2)
      real*8   ninety
      PARAMETER ( ninety = 90. )
      integer  i, j, k, l, js, bi, bj, sp, interp_unit
      _RS      xG(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
      _RS      threeSixtyRS, NorthValue
      PARAMETER ( threeSixtyRS = 360. )

C     put xG in interval [ lon_0 , lon_0+360 [
      do bj=myByLo(myThid),myByHi(myThid)
       do bi=myBxLo(myThid),myBxHi(myThid)
        do j=1-OLy,sNy+OLy
         do i=1-OLx,sNx+OLx
          xG(i,j,bi,bj) = xG_in(i,j,bi,bj)-lon_0
     &                  + threeSixtyRS*2.
          xG(i,j,bi,bj) = lon_0+mod(xG(i,j,bi,bj),threeSixtyRS)
         enddo
        enddo
       enddo
      enddo

       call exf_interp_read(
     I   infile, filePrec,
     O   arrayin,
     I   irecord, nx_in, ny_in, mythid)
      _BARRIER

C     _BEGIN_MASTER( myThid )

C setup input longitude grid
      do i=-1,nx_in+2
       x_in(i) = lon_0 + (i-1)*lon_inc
      enddo

C setup input latitude grid
      y_in(0) = lat_0 - lat_inc(1)
      y_in(-1)= lat_0 - 2.*lat_inc(1)
      y_in(1) = lat_0
      do j=2,ny_in
       y_in(j) = y_in(j-1) + lat_inc(j-1)
      enddo
      do j=ny_in+1,ny_in+2
       if (y_in(j-1).eq.ninety) then
        y_in(j) = 2 * ninety - y_in(j-2)
       else
        y_in(j) = min( y_in(j-1)+lat_inc(ny_in-1), ninety )
       endif
      enddo

C enlarge boundary
      do j=1,ny_in
       arrayin(0,j)       = arrayin(nx_in,j)
       arrayin(-1,j)      = arrayin(nx_in-1,j)
       arrayin(nx_in+1,j) = arrayin(1,j)
       arrayin(nx_in+2,j) = arrayin(2,j)
      enddo
      do i=-1,nx_in+2
       arrayin(i,0)       = arrayin(i,1)
       arrayin(i,-1)      = arrayin(i,1)
       arrayin(i,ny_in+1) = arrayin(i,ny_in)
       arrayin(i,ny_in+2) = arrayin(i,ny_in) 
      enddo

C     For tracer (method=1,2) set to northernmost zonal-mean value
C     at 90N to avoid sharp zonal gradients near the Pole.
C     For U (method=11,12) set to zero at 90N to minimize velocity
C     gradient at North Pole
C     For V (method=11,12) set to northernmost zonal value at 90N,
C     as is already done above in order to allow cross-PoleArctic flow
      do j=ny_in,ny_in+2
       if (y_in(j).eq.ninety) then
        if (method.eq.1 .or. method.eq.2) then
         NorthValue = 0
         do i=1,nx_in
          NorthValue = NorthValue + arrayin(i,j)
         enddo
         NorthValue = NorthValue / nx_in
         do i=-1,nx_in+2
          arrayin(i,j) = NorthValue
         enddo
        elseif (method.eq.11 .or. method.eq.12) then
         do i=-1,nx_in+2
          arrayin(i,j) = 0
         enddo
        endif
       endif
      enddo

C     _END_MASTER( myThid )
       
      do bj = mybylo(mythid), mybyhi(mythid)
       do bi = mybxlo(mythid), mybxhi(mythid)

C check validity of input/output coordinates
#ifdef ALLOW_DEBUG
        if ( debugLevel .ge. debLevB ) then
         do i=1,snx
          do j=1,sny
           if ( xG(i,j,bi,bj) .lt. x_in(0)         .or.
     &          xG(i,j,bi,bj) .ge. x_in(nx_in+1)   .or.
     &          yG(i,j,bi,bj) .lt. y_in(0)         .or.
     &          yG(i,j,bi,bj) .ge. y_in(ny_in+1) ) then
              print*,'ERROR in S/R EXF_INTERP:'
              print*,'   input grid must encompass output grid.'
              print*,'i,j,bi,bj'      ,i,j,bi,bj
              print*,'xG,yG'          ,xG(i,j,bi,bj),yG(i,j,bi,bj)
              print*,'nx_in,ny_in'    ,nx_in        ,ny_in
              print*,'x_in(0,nx_in+1)',x_in(0)      ,x_in(nx_in+1)
              print*,'y_in(0,ny_in+1)',y_in(0)      ,y_in(ny_in+1)
              STOP   ' ABNORMAL END: S/R EXF_INTERP'
             endif
           enddo
         enddo
        endif
#endif /* ALLOW_DEBUG */

C compute interpolation indices 
        do i=1,snx
         do j=1,sny
          if (xG(i,j,bi,bj)-x_in(1) .ge. 0.) then
           w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc) + 1
          else
           w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc)
          endif
          e_ind(i,j) = w_ind(i,j) + 1
          js = ny_in*.5
          do while (yG(i,j,bi,bj) .lt. y_in(js))
           js = (js - 1)*.5
          enddo
          do while (yG(i,j,bi,bj) .ge. y_in(js+1))
           js = js + 1
          enddo
          s_ind(i,j) = js
          n_ind(i,j) = js + 1
         enddo
        enddo

        if (method.eq.1 .or. method.eq.11 .or. method.eq.21) then

C bilinear interpolation
         sp = 2
         do j=1,sny
          do i=1,snx
           arrayout(i,j,bi,bj) = 0.
           do l=0,1
            px_ind(l+1) = x_in(w_ind(i,j)+l)
            py_ind(l+1) = y_in(s_ind(i,j)+l)
           enddo
           do k=1,2
            ew_val(k) = arrayin(w_ind(i,j),s_ind(i,j)+k-1)
     &             *lagran(1,xG(i,j,bi,bj),px_ind,sp)
     &             +arrayin(e_ind(i,j),s_ind(i,j)+k-1)
     &             *lagran(2,xG(i,j,bi,bj),px_ind,sp)
            arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
     &             +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
           enddo
          enddo
         enddo
        elseif (method .eq. 2 .or. method.eq.12 .or. method.eq.22) then

C bicubic interpolation
         sp = 4
         do j=1,sny
          do i=1,snx
           arrayout(i,j,bi,bj) = 0.
           do l=-1,2
            px_ind(l+2) = x_in(w_ind(i,j)+l)
            py_ind(l+2) = y_in(s_ind(i,j)+l)
           enddo
           do k=1,4
            ew_val(k) =
     &             arrayin(w_ind(i,j)-1,s_ind(i,j)+k-2)
     &             *lagran(1,xG(i,j,bi,bj),px_ind,sp)
     &             +arrayin(w_ind(i,j)  ,s_ind(i,j)+k-2)
     &             *lagran(2,xG(i,j,bi,bj),px_ind,sp)
     &             +arrayin(e_ind(i,j)  ,s_ind(i,j)+k-2)
     &             *lagran(3,xG(i,j,bi,bj),px_ind,sp) 
     &             +arrayin(e_ind(i,j)+1,s_ind(i,j)+k-2)
     &             *lagran(4,xG(i,j,bi,bj),px_ind,sp)
            arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj) 
     &             +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
           enddo
          enddo
         enddo
        else
         stop 'stop in exf_interp.F: interpolation method not supported'
        endif
       enddo
      enddo

      END
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	heimbach	1.13	I irecord, xG_in, yG,
40	dimitri	1.2	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	1.15	C method = 1,11,21 for bilinear; 2,12,22 for bicubic
56			C 1,2 for tracer; 11,12 for U; 21,22 for V
57	dimitri	1.2	C mythid = thread id
58	dimitri	1.1	C
59
60			#include "SIZE.h"
61			#include "EEPARAMS.h"
62	adcroft	1.7	#include "PARAMS.h"
63	dimitri	1.2
64			C subroutine variables
65			character() infile
66			integer filePrec, irecord, nx_in, ny_in
67			_RL arrayout(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
68	heimbach	1.12	_RS xG_in (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
69	dimitri	1.2	_RS yG (1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
70			_RL lon_0, lon_inc
71			_RL lat_0, lat_inc(ny_in-1)
72			integer method, mythid
73	dimitri	1.1
74			C local variables
75	dimitri	1.5	integer e_ind(snx,sny),w_ind(snx,sny)
76			integer n_ind(snx,sny),s_ind(snx,sny)
77	dimitri	1.2	real*8 px_ind(4), py_ind(4), ew_val(4)
78	dimitri	1.1	external lagran
79	dimitri	1.2	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	dimitri	1.17	real*8 ninety
83			PARAMETER ( ninety = 90. )
84	dimitri	1.5	integer i, j, k, l, js, bi, bj, sp, interp_unit
85	heimbach	1.13	_RS xG(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
86	dimitri	1.15	_RS threeSixtyRS, NorthValue
87	heimbach	1.13	PARAMETER ( threeSixtyRS = 360. )
88	heimbach	1.12
89	jmc	1.14	C put xG in interval [ lon_0 , lon_0+360 [
90	heimbach	1.12	do bj=myByLo(myThid),myByHi(myThid)
91			do bi=myBxLo(myThid),myBxHi(myThid)
92			do j=1-OLy,sNy+OLy
93			do i=1-OLx,sNx+OLx
94	jmc	1.14	xG(i,j,bi,bj) = xG_in(i,j,bi,bj)-lon_0
95			& + threeSixtyRS*2.
96			xG(i,j,bi,bj) = lon_0+mod(xG(i,j,bi,bj),threeSixtyRS)
97	heimbach	1.12	enddo
98			enddo
99			enddo
100			enddo
101	heimbach	1.9
102			call exf_interp_read(
103	dimitri	1.15	I infile, filePrec,
104	heimbach	1.9	O arrayin,
105	dimitri	1.15	I irecord, nx_in, ny_in, mythid)
106	cnh	1.11	_BARRIER
107	dimitri	1.4
108	cnh	1.11	C _BEGIN_MASTER( myThid )
109	dimitri	1.2
110	dimitri	1.18	C setup input longitude grid
111			do i=-1,nx_in+2
112			x_in(i) = lon_0 + (i-1)*lon_inc
113			enddo
114	heimbach	1.12
115	dimitri	1.18	C setup input latitude grid
116			y_in(0) = lat_0 - lat_inc(1)
117			y_in(-1)= lat_0 - 2.*lat_inc(1)
118			y_in(1) = lat_0
119			do j=2,ny_in
120			y_in(j) = y_in(j-1) + lat_inc(j-1)
121			enddo
122			do j=ny_in+1,ny_in+2
123			if (y_in(j-1).eq.ninety) then
124			y_in(j) = 2 * ninety - y_in(j-2)
125			else
126			y_in(j) = min( y_in(j-1)+lat_inc(ny_in-1), ninety )
127			endif
128			enddo
129	dimitri	1.1
130			C enlarge boundary
131	dimitri	1.18	do j=1,ny_in
132			arrayin(0,j) = arrayin(nx_in,j)
133			arrayin(-1,j) = arrayin(nx_in-1,j)
134			arrayin(nx_in+1,j) = arrayin(1,j)
135			arrayin(nx_in+2,j) = arrayin(2,j)
136			enddo
137			do i=-1,nx_in+2
138			arrayin(i,0) = arrayin(i,1)
139			arrayin(i,-1) = arrayin(i,1)
140			arrayin(i,ny_in+1) = arrayin(i,ny_in)
141			arrayin(i,ny_in+2) = arrayin(i,ny_in)
142			enddo
143	dimitri	1.4
144	dimitri	1.15	C For tracer (method=1,2) set to northernmost zonal-mean value
145			C at 90N to avoid sharp zonal gradients near the Pole.
146			C For U (method=11,12) set to zero at 90N to minimize velocity
147			C gradient at North Pole
148			C For V (method=11,12) set to northernmost zonal value at 90N,
149			C as is already done above in order to allow cross-PoleArctic flow
150	dimitri	1.18	do j=ny_in,ny_in+2
151			if (y_in(j).eq.ninety) then
152	dimitri	1.15	if (method.eq.1 .or. method.eq.2) then
153			NorthValue = 0
154			do i=1,nx_in
155	dimitri	1.18	NorthValue = NorthValue + arrayin(i,j)
156	dimitri	1.15	enddo
157			NorthValue = NorthValue / nx_in
158			do i=-1,nx_in+2
159	dimitri	1.18	arrayin(i,j) = NorthValue
160	dimitri	1.15	enddo
161			elseif (method.eq.11 .or. method.eq.12) then
162			do i=-1,nx_in+2
163	dimitri	1.18	arrayin(i,j) = 0
164	dimitri	1.15	enddo
165			endif
166			endif
167	dimitri	1.18	enddo
168	dimitri	1.15
169	cnh	1.11	C _END_MASTER( myThid )
170	dimitri	1.15
171	dimitri	1.2	do bj = mybylo(mythid), mybyhi(mythid)
172			do bi = mybxlo(mythid), mybxhi(mythid)
173
174			C check validity of input/output coordinates
175	dimitri	1.6	#ifdef ALLOW_DEBUG
176			if ( debugLevel .ge. debLevB ) then
177			do i=1,snx
178			do j=1,sny
179			if ( xG(i,j,bi,bj) .lt. x_in(0) .or.
180			& xG(i,j,bi,bj) .ge. x_in(nx_in+1) .or.
181			& yG(i,j,bi,bj) .lt. y_in(0) .or.
182			& yG(i,j,bi,bj) .ge. y_in(ny_in+1) ) then
183			print*,'ERROR in S/R EXF_INTERP:'
184			print*,' input grid must encompass output grid.'
185			print*,'i,j,bi,bj' ,i,j,bi,bj
186			print*,'xG,yG' ,xG(i,j,bi,bj),yG(i,j,bi,bj)
187			print*,'nx_in,ny_in' ,nx_in ,ny_in
188			print*,'x_in(0,nx_in+1)',x_in(0) ,x_in(nx_in+1)
189			print*,'y_in(0,ny_in+1)',y_in(0) ,y_in(ny_in+1)
190			STOP ' ABNORMAL END: S/R EXF_INTERP'
191			endif
192			enddo
193			enddo
194	dimitri	1.2	endif
195	dimitri	1.6	#endif /* ALLOW_DEBUG */
196	dimitri	1.1
197			C compute interpolation indices
198			do i=1,snx
199	dimitri	1.5	do j=1,sny
200			if (xG(i,j,bi,bj)-x_in(1) .ge. 0.) then
201			w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc) + 1
202			else
203			w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc)
204			endif
205			e_ind(i,j) = w_ind(i,j) + 1
206	dimitri	1.6	js = ny_in*.5
207	dimitri	1.5	do while (yG(i,j,bi,bj) .lt. y_in(js))
208	dimitri	1.6	js = (js - 1)*.5
209	dimitri	1.5	enddo
210			do while (yG(i,j,bi,bj) .ge. y_in(js+1))
211			js = js + 1
212			enddo
213			s_ind(i,j) = js
214			n_ind(i,j) = js + 1
215	dimitri	1.2	enddo
216	dimitri	1.1	enddo
217
218	dimitri	1.15	if (method.eq.1 .or. method.eq.11 .or. method.eq.21) then
219	dimitri	1.1
220	dimitri	1.2	C bilinear interpolation
221			sp = 2
222			do j=1,sny
223			do i=1,snx
224	dimitri	1.1	arrayout(i,j,bi,bj) = 0.
225	dimitri	1.2	do l=0,1
226	dimitri	1.5	px_ind(l+1) = x_in(w_ind(i,j)+l)
227			py_ind(l+1) = y_in(s_ind(i,j)+l)
228	dimitri	1.1	enddo
229	dimitri	1.2	do k=1,2
230	dimitri	1.5	ew_val(k) = arrayin(w_ind(i,j),s_ind(i,j)+k-1)
231			& *lagran(1,xG(i,j,bi,bj),px_ind,sp)
232			& +arrayin(e_ind(i,j),s_ind(i,j)+k-1)
233			& *lagran(2,xG(i,j,bi,bj),px_ind,sp)
234	dimitri	1.2	arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
235	dimitri	1.5	& +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
236	dimitri	1.1	enddo
237			enddo
238			enddo
239	dimitri	1.15	elseif (method .eq. 2 .or. method.eq.12 .or. method.eq.22) then
240	dimitri	1.1
241	dimitri	1.2	C bicubic interpolation
242			sp = 4
243			do j=1,sny
244			do i=1,snx
245	dimitri	1.1	arrayout(i,j,bi,bj) = 0.
246	dimitri	1.2	do l=-1,2
247	dimitri	1.5	px_ind(l+2) = x_in(w_ind(i,j)+l)
248			py_ind(l+2) = y_in(s_ind(i,j)+l)
249	dimitri	1.1	enddo
250	dimitri	1.2	do k=1,4
251			ew_val(k) =
252	dimitri	1.5	& arrayin(w_ind(i,j)-1,s_ind(i,j)+k-2)
253			& *lagran(1,xG(i,j,bi,bj),px_ind,sp)
254			& +arrayin(w_ind(i,j) ,s_ind(i,j)+k-2)
255			& *lagran(2,xG(i,j,bi,bj),px_ind,sp)
256			& +arrayin(e_ind(i,j) ,s_ind(i,j)+k-2)
257			& *lagran(3,xG(i,j,bi,bj),px_ind,sp)
258			& +arrayin(e_ind(i,j)+1,s_ind(i,j)+k-2)
259			& *lagran(4,xG(i,j,bi,bj),px_ind,sp)
260	dimitri	1.2	arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
261	dimitri	1.5	& +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
262	dimitri	1.1	enddo
263	dimitri	1.2	enddo
264	dimitri	1.1	enddo
265	dimitri	1.2	else
266			stop 'stop in exf_interp.F: interpolation method not supported'
267			endif
268			enddo
269			enddo
270	dimitri	1.1
271			END