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, 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 for bilinear 2 for bicubic
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      (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
      real*8   ne_fac,nw_fac,se_fac,sw_fac
      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)
      integer  i, j, k, l, js, bi, bj, sp, interp_unit

       call exf_interp_read(
     I   infile,
     I   filePrec,
     O   arrayin,
     I   irecord, xG, yG,
     I   lon_0, lon_inc,
     I   lat_0, lat_inc,
     I   nx_in, ny_in, method, mythid)
      _BARRIER

C     _BEGIN_MASTER( myThid )

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

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     _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) 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) 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	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	adcroft	1.7	#include "PARAMS.h"
62	dimitri	1.2
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 (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	dimitri	1.1
73			C local variables
74	dimitri	1.2	real*8 ne_fac,nw_fac,se_fac,sw_fac
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	1.5	integer i, j, k, l, js, bi, bj, sp, interp_unit
83	heimbach	1.9
84			call exf_interp_read(
85			I infile,
86			I filePrec,
87			O arrayin,
88			I irecord, xG, yG,
89			I lon_0, lon_inc,
90			I lat_0, lat_inc,
91			I nx_in, ny_in, method, mythid)
92	cnh	1.11	_BARRIER
93	dimitri	1.4
94	cnh	1.11	C _BEGIN_MASTER( myThid )
95	dimitri	1.2
96	dimitri	1.1	C setup input grid
97	dimitri	1.4	do i=-1,nx_in+2
98			x_in(i) = lon_0 + (i-1.)*lon_inc
99			enddo
100			y_in(0) = lat_0 - lat_inc(1)
101			y_in(-1)= lat_0 - 2.*lat_inc(1)
102			y_in(1) = lat_0
103			do j=2,ny_in
104			y_in(j) = y_in(j-1) + lat_inc(j-1)
105			enddo
106			y_in(ny_in+1) = y_in(ny_in) + lat_inc(ny_in-1)
107			y_in(ny_in+2) = y_in(ny_in) + 2.*lat_inc(ny_in-1)
108	dimitri	1.1
109			C enlarge boundary
110	dimitri	1.4	do j=1,ny_in
111			arrayin(0,j) = arrayin(nx_in,j)
112			arrayin(-1,j) = arrayin(nx_in-1,j)
113			arrayin(nx_in+1,j) = arrayin(1,j)
114			arrayin(nx_in+2,j) = arrayin(2,j)
115			enddo
116			do i=-1,nx_in+2
117			arrayin(i,0) = arrayin(i,1)
118			arrayin(i,-1) = arrayin(i,1)
119			arrayin(i,ny_in+1) = arrayin(i,ny_in)
120			arrayin(i,ny_in+2) = arrayin(i,ny_in)
121			enddo
122
123	cnh	1.11	C _END_MASTER( myThid )
124	dimitri	1.2
125			do bj = mybylo(mythid), mybyhi(mythid)
126			do bi = mybxlo(mythid), mybxhi(mythid)
127
128			C check validity of input/output coordinates
129	dimitri	1.6	#ifdef ALLOW_DEBUG
130			if ( debugLevel .ge. debLevB ) then
131			do i=1,snx
132			do j=1,sny
133			if ( xG(i,j,bi,bj) .lt. x_in(0) .or.
134			& xG(i,j,bi,bj) .ge. x_in(nx_in+1) .or.
135			& yG(i,j,bi,bj) .lt. y_in(0) .or.
136			& yG(i,j,bi,bj) .ge. y_in(ny_in+1) ) then
137			print*,'ERROR in S/R EXF_INTERP:'
138			print*,' input grid must encompass output grid.'
139			print*,'i,j,bi,bj' ,i,j,bi,bj
140			print*,'xG,yG' ,xG(i,j,bi,bj),yG(i,j,bi,bj)
141			print*,'nx_in,ny_in' ,nx_in ,ny_in
142			print*,'x_in(0,nx_in+1)',x_in(0) ,x_in(nx_in+1)
143			print*,'y_in(0,ny_in+1)',y_in(0) ,y_in(ny_in+1)
144			STOP ' ABNORMAL END: S/R EXF_INTERP'
145			endif
146			enddo
147			enddo
148	dimitri	1.2	endif
149	dimitri	1.6	#endif /* ALLOW_DEBUG */
150	dimitri	1.1
151			C compute interpolation indices
152			do i=1,snx
153	dimitri	1.5	do j=1,sny
154			if (xG(i,j,bi,bj)-x_in(1) .ge. 0.) then
155			w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc) + 1
156			else
157			w_ind(i,j) = int((xG(i,j,bi,bj)-x_in(1))/lon_inc)
158			endif
159			e_ind(i,j) = w_ind(i,j) + 1
160	dimitri	1.6	js = ny_in*.5
161	dimitri	1.5	do while (yG(i,j,bi,bj) .lt. y_in(js))
162	dimitri	1.6	js = (js - 1)*.5
163	dimitri	1.5	enddo
164			do while (yG(i,j,bi,bj) .ge. y_in(js+1))
165			js = js + 1
166			enddo
167			s_ind(i,j) = js
168			n_ind(i,j) = js + 1
169	dimitri	1.2	enddo
170	dimitri	1.1	enddo
171
172	dimitri	1.2	if (method .eq. 1) then
173	dimitri	1.1
174	dimitri	1.2	C bilinear interpolation
175			sp = 2
176			do j=1,sny
177			do i=1,snx
178	dimitri	1.1	arrayout(i,j,bi,bj) = 0.
179	dimitri	1.2	do l=0,1
180	dimitri	1.5	px_ind(l+1) = x_in(w_ind(i,j)+l)
181			py_ind(l+1) = y_in(s_ind(i,j)+l)
182	dimitri	1.1	enddo
183	dimitri	1.2	do k=1,2
184	dimitri	1.5	ew_val(k) = arrayin(w_ind(i,j),s_ind(i,j)+k-1)
185			& *lagran(1,xG(i,j,bi,bj),px_ind,sp)
186			& +arrayin(e_ind(i,j),s_ind(i,j)+k-1)
187			& *lagran(2,xG(i,j,bi,bj),px_ind,sp)
188	dimitri	1.2	arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
189	dimitri	1.5	& +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
190	dimitri	1.1	enddo
191			enddo
192			enddo
193	dimitri	1.2	elseif (method .eq. 2) then
194	dimitri	1.1
195	dimitri	1.2	C bicubic interpolation
196			sp = 4
197			do j=1,sny
198			do i=1,snx
199	dimitri	1.1	arrayout(i,j,bi,bj) = 0.
200	dimitri	1.2	do l=-1,2
201	dimitri	1.5	px_ind(l+2) = x_in(w_ind(i,j)+l)
202			py_ind(l+2) = y_in(s_ind(i,j)+l)
203	dimitri	1.1	enddo
204	dimitri	1.2	do k=1,4
205			ew_val(k) =
206	dimitri	1.5	& arrayin(w_ind(i,j)-1,s_ind(i,j)+k-2)
207			& *lagran(1,xG(i,j,bi,bj),px_ind,sp)
208			& +arrayin(w_ind(i,j) ,s_ind(i,j)+k-2)
209			& *lagran(2,xG(i,j,bi,bj),px_ind,sp)
210			& +arrayin(e_ind(i,j) ,s_ind(i,j)+k-2)
211			& *lagran(3,xG(i,j,bi,bj),px_ind,sp)
212			& +arrayin(e_ind(i,j)+1,s_ind(i,j)+k-2)
213			& *lagran(4,xG(i,j,bi,bj),px_ind,sp)
214	dimitri	1.2	arrayout(i,j,bi,bj)=arrayout(i,j,bi,bj)
215	dimitri	1.5	& +ew_val(k)*lagran(k,yG(i,j,bi,bj),py_ind,sp)
216	dimitri	1.1	enddo
217	dimitri	1.2	enddo
218	dimitri	1.1	enddo
219	dimitri	1.2	else
220			stop 'stop in exf_interp.F: interpolation method not supported'
221			endif
222			enddo
223			enddo
224	dimitri	1.1
225			END