/[MITgcm]/MITgcm/pkg/flt/flt_interp_linear.F
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Revision 1.1 - (hide annotations) (download)
Sun Feb 1 21:10:51 2009 UTC (15 years, 4 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint64y, checkpoint64x, checkpoint64z, checkpoint64q, checkpoint64p, checkpoint64s, checkpoint64r, checkpoint64u, checkpoint64t, checkpoint64w, checkpoint64v, checkpoint64i, checkpoint64h, checkpoint64k, checkpoint64j, checkpoint64m, checkpoint64l, checkpoint64o, checkpoint64n, checkpoint64a, checkpoint64c, checkpoint64b, checkpoint64e, checkpoint64d, checkpoint64g, checkpoint64f, checkpoint63p, checkpoint63q, checkpoint63r, checkpoint63s, checkpoint63l, checkpoint63m, checkpoint63n, checkpoint63o, checkpoint63h, checkpoint63i, checkpoint63j, checkpoint63k, checkpoint63d, checkpoint63e, checkpoint63f, checkpoint63g, checkpoint63a, checkpoint63b, checkpoint63c, checkpoint64, checkpoint65, checkpoint62, checkpoint63, checkpoint66g, checkpoint66f, checkpoint66e, checkpoint66d, checkpoint66c, checkpoint66b, checkpoint66a, checkpoint66o, checkpoint66n, checkpoint66m, checkpoint66l, checkpoint66k, checkpoint66j, checkpoint66i, checkpoint66h, checkpoint65z, checkpoint65x, checkpoint65y, checkpoint65r, checkpoint65s, checkpoint65p, checkpoint65q, checkpoint65v, checkpoint65w, checkpoint65t, checkpoint65u, checkpoint65j, checkpoint65k, checkpoint65h, checkpoint65i, checkpoint65n, checkpoint65o, checkpoint65l, checkpoint65m, checkpoint65b, checkpoint65c, checkpoint65a, checkpoint65f, checkpoint65g, checkpoint65d, checkpoint65e, checkpoint62c, checkpoint62b, checkpoint62a, checkpoint62g, checkpoint62f, checkpoint62e, checkpoint62d, checkpoint62k, checkpoint62j, checkpoint62i, checkpoint62h, checkpoint62o, checkpoint62n, checkpoint62m, checkpoint62l, checkpoint62s, checkpoint62r, checkpoint62q, checkpoint62p, checkpoint62w, checkpoint62v, checkpoint62u, checkpoint62t, checkpoint62z, checkpoint62y, checkpoint62x, checkpoint61n, checkpoint61o, checkpoint61l, checkpoint61m, checkpoint61j, checkpoint61k, checkpoint61i, checkpoint61v, checkpoint61w, checkpoint61t, checkpoint61u, checkpoint61r, checkpoint61s, checkpoint61p, checkpoint61q, checkpoint61z, checkpoint61x, checkpoint61y, HEAD 
- clean-up & simplify linear interpolation S/R :
  (move flt_bilinear.F -> flt_interp_linear.F ; add arg. myThid ; add
   option for var @ corner position)
- fix some indices (mainly vertical index)
- uses IMPLICIT NONE
1 jmc 1.1 C $Header: /u/gcmpack/MITgcm/pkg/flt/flt_bilinear.F,v 1.4 2009/01/04 00:58:23 jmc Exp $
2     C $Name: $
3    
4     #include "FLT_OPTIONS.h"
5    
6     C-- Contents
7     C-- o FLT_BILINEAR
8     C-- o FLT_TRILINEAR
9     C-- o FLT_BILINEAR2D
10    
11     C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
12    
13     SUBROUTINE FLT_BILINEAR(
14     I ix, jy,
15     O uu,
16     I var,
17     I kl, nu, bi, bj, myThid )
18    
19     C ==================================================================
20     C SUBROUTINE FLT_BILINEAR
21     C ==================================================================
22     C o Bilinear scheme to interpolate variable to particle position
23     C given by its fractional (real) index ix,jy location
24     C ==================================================================
25    
26     C !USES:
27     IMPLICIT NONE
28    
29     C == global variables ==
30     #include "SIZE.h"
31    
32     C == routine arguments ==
33     _RL ix, jy
34     _RL uu
35     _RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
36     INTEGER kl, nu, bi, bj, myThid
37    
38     C == local variables ==
39     INTEGER i1, j1, i2, j2, klp
40     _RL ddx, ddy
41     _RL u11, u12, u22, u21
42    
43     C == end of interface ==
44    
45     C-- to choose the u box in which the particle is found
46     C nu=0 for T, S
47     C nu=1 for u
48     C nu=2 for v
49     C nu=3 for Vorticity
50     C nu=4 for w
51    
52     IF ( kl.LT.1 .OR. kl.GT.Nr ) THEN
53     c WRITE(msgbuf,'(A,I8)')
54     c & ' FLT_BILINEAR: illegal value for kl=',kl
55     c CALL PRINT_ERROR( msgbuf, myThid )
56     STOP 'ABNORMAL END: S/R FLT_BILINEAR'
57     ENDIF
58    
59     C-- find x-index according to grid-location of variable
60     IF ( MOD(nu,2).EQ.0 ) THEN
61     i1 = INT(ix)
62     ddx = ix - DFLOAT(i1)
63     ELSE
64     i1 = NINT(ix)
65     ddx = 0.5 _d 0 + ix - DFLOAT(i1)
66     ENDIF
67     C-- find y-index according to grid-location of variable
68     IF ( MOD(nu,4).LE.1 ) THEN
69     j1 = INT(jy)
70     ddy = jy - DFLOAT(j1)
71     ELSE
72     j1 = NINT(jy)
73     ddy = 0.5 _d 0 + jy - DFLOAT(j1)
74     ENDIF
75    
76     C-- Set the higher index for interpolation
77     i2 = i1 + 1
78     j2 = j1 + 1
79    
80     C-- No need to change start/end index : use array overlap if needed
81    
82     C-- bilinear interpolation (from numerical recipes)
83     IF (nu.LE.3) THEN
84     uu = ( (1.-ddx)*(1.-ddy)*var(i1,j1,kl,bi,bj)
85     & + ddx * ddy *var(i2,j2,kl,bi,bj) )
86     & + ( ddx *(1.-ddy)*var(i2,j1,kl,bi,bj)
87     & + (1.-ddx)* ddy *var(i1,j2,kl,bi,bj) )
88     ELSE
89     klp = MIN(kl+1,Nr)
90     u11 = ( var(i1,j1,kl,bi,bj)+var(i1,j1,klp,bi,bj) )*0.5 _d 0
91     u21 = ( var(i2,j1,kl,bi,bj)+var(i2,j1,klp,bi,bj) )*0.5 _d 0
92     u22 = ( var(i2,j2,kl,bi,bj)+var(i2,j2,klp,bi,bj) )*0.5 _d 0
93     u12 = ( var(i1,j2,kl,bi,bj)+var(i1,j2,klp,bi,bj) )*0.5 _d 0
94     uu = ( (1.-ddx)*(1.-ddy)*u11
95     & + ddx * ddy *u22 )
96     & + ( ddx *(1.-ddy)*u21
97     & + (1.-ddx)* ddy *u12 )
98     ENDIF
99    
100    
101     RETURN
102     END
103    
104     C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
105    
106     SUBROUTINE FLT_TRILINEAR(
107     I ix, jy, kz,
108     O uu,
109     I var,
110     I nu, bi, bj, myThid )
111    
112     C ==================================================================
113     C SUBROUTINE FLT_TRILINEAR
114     C ==================================================================
115     C o Trilinear scheme to interpolate variable to particle position
116     C given by its fractional (real) index ix,jy,kz location
117     C This routine is a straight forward generalization of the
118     C bilinear interpolation scheme.
119     C
120     C started: 2004.05.28 Antti Westerlund (antti.westerlund@fimr.fi)
121     C and Sergio Jaramillo (sju@eos.ubc.ca).
122     C (adopted from SUBROUTINE bilinear by Arne Biastoch)
123     C ==================================================================
124    
125     C !USES:
126     IMPLICIT NONE
127    
128     C == global variables ==
129     #include "SIZE.h"
130    
131     C == routine arguments ==
132     _RL ix, jy, kz
133     _RL uu
134     _RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr,nSx,nSy)
135     INTEGER nu, bi, bj, myThid
136    
137     C == local variables ==
138     INTEGER i1, j1, k1, i2, j2, k2
139     _RL ddx, ddy, ddz
140    
141     C == end of interface ==
142    
143     C to choose the u box in which the particle is found
144     C nu=0 for T, S
145     C nu=1 for u
146     C nu=2 for v
147     C nu=3 for Vorticity
148     C nu=4 for w
149    
150     C-- find x-index according to grid-location of variable
151     IF ( MOD(nu,2).EQ.0 ) THEN
152     i1 = INT(ix)
153     ddx = ix - DFLOAT(i1)
154     ELSE
155     i1 = NINT(ix)
156     ddx = 0.5 _d 0 + ix - DFLOAT(i1)
157     ENDIF
158     C-- find y-index according to grid-location of variable
159     IF ( MOD(nu,4).LE.1 ) THEN
160     j1 = INT(jy)
161     ddy = jy - DFLOAT(j1)
162     ELSE
163     j1 = NINT(jy)
164     ddy = 0.5 _d 0 + jy - DFLOAT(j1)
165     ENDIF
166     C-- find z-index according to grid-location of variable
167     IF ( nu.LE.3 ) THEN
168     k1 = INT(kz)
169     ddz = kz - DFLOAT(k1)
170     ELSE
171     k1 = NINT(kz)
172     ddz = 0.5 _d 0 + kz - DFLOAT(k1)
173     ENDIF
174    
175     C-- Set the higher index for interpolation
176     i2 = i1 + 1
177     j2 = j1 + 1
178     k2 = k1 + 1
179    
180     C-- No need to change start/end horizontal index : use array overlap if needed
181     C-- Need to adjust start/end vertical index :
182     k1 = MIN( MAX( k1, 1 ), Nr )
183     k2 = MIN( MAX( k2, 1 ), Nr )
184    
185     C Trilinear interpolation, a straight forward generalization
186     C of the bilinear interpolation scheme.
187     uu = (1.-ddz)*( ( (1.-ddx)*(1.-ddy)*var(i1,j1,k1,bi,bj)
188     & + ddx * ddy *var(i2,j2,k1,bi,bj) )
189     & + ( ddx *(1.-ddy)*var(i2,j1,k1,bi,bj)
190     & + (1.-ddx)* ddy *var(i1,j2,k1,bi,bj) ) )
191     & + ddz *( ( (1.-ddx)*(1.-ddy)*var(i1,j1,k2,bi,bj)
192     & + ddx * ddy *var(i2,j2,k2,bi,bj) )
193     & + ( ddx*(1.-ddy) *var(i2,j1,k2,bi,bj)
194     & + (1.-ddx)* ddy *var(i1,j2,k2,bi,bj) ) )
195    
196     RETURN
197     END
198    
199     C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
200    
201     SUBROUTINE FLT_BILINEAR2D(
202     I ix, jy,
203     O uu,
204     I var,
205     I nu, bi, bj, myThid )
206    
207     C ==================================================================
208     C SUBROUTINE FLT_BILINEAR2D
209     C ==================================================================
210     C o Bilinear scheme to interpolate 2-D variable to particle position
211     C given by its fractional (real) index ix,jy location
212     C
213     C started: Arne Biastoch abiastoch@ucsd.edu 13-Jan-2000
214     C (adopted from SUBROUTINE bilinear)
215     C ==================================================================
216    
217     C !USES:
218     IMPLICIT NONE
219    
220     C == global variables ==
221     #include "SIZE.h"
222    
223     C == routine arguments ==
224     _RL ix, jy
225     _RL uu
226     _RL var(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
227     INTEGER nu, bi, bj, myThid
228    
229     C == local variables ==
230     INTEGER i1, j1, i2, j2
231     _RL ddx, ddy
232    
233     C == end of interface ==
234    
235     C to choose the u box in which the particle is found
236     C nu=0 for T, S
237     C nu=1 for u
238     C nu=2 for v
239     C nu=3 for Vorticity
240     C nu=4 for w
241    
242     C-- find x-index according to grid-location of variable
243     IF ( MOD(nu,2).EQ.0 ) THEN
244     i1 = INT(ix)
245     ddx = ix - DFLOAT(i1)
246     ELSE
247     i1 = NINT(ix)
248     ddx = 0.5 _d 0 + ix - DFLOAT(i1)
249     ENDIF
250     C-- find y-index according to grid-location of variable
251     IF ( MOD(nu,4).LE.1 ) THEN
252     j1 = INT(jy)
253     ddy = jy - DFLOAT(j1)
254     ELSE
255     j1 = NINT(jy)
256     ddy = 0.5 _d 0 + jy - DFLOAT(j1)
257     ENDIF
258    
259     C-- Set the higher index for interpolation
260     i2 = i1 + 1
261     j2 = j1 + 1
262    
263     C-- No need to change start/end index : use array overlap if needed
264    
265     C bilinear interpolation (from numerical recipes)
266     uu = ( (1.-ddx)*(1.-ddy)*var(i1,j1,bi,bj)
267     & + ddx * ddy *var(i2,j2,bi,bj) )
268     & + ( ddx *(1.-ddy)*var(i2,j1,bi,bj)
269     & + (1.-ddx)* ddy *var(i1,j2,bi,bj) )
270    
271     RETURN
272     END
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