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1
      PROGRAM timeresolution
1
      PROGRAM timeresolution
2
      
2
      
3
c     ***********************************************************************
3
c     ***********************************************************************
4
c     * Change time resolution of of a trajectory file                      *
4
c     * Change time resolution of of a trajectory file                      *
5
c     * Michael Sprenger / Winter 2010                                      *
5
c     * Michael Sprenger / Winter 2010                                      *
6
c     ***********************************************************************
6
c     ***********************************************************************
7
 
7
 
8
      implicit none
8
      implicit none
9
      
9
      
10
c     ----------------------------------------------------------------------
10
c     ----------------------------------------------------------------------
11
c     Declaration of variables
11
c     Declaration of variables
12
c     ----------------------------------------------------------------------
12
c     ----------------------------------------------------------------------
13
 
13
 
14
c     Parameters
14
c     Parameters
15
      character*80                           inpfile     
15
      character*80                           inpfile     
16
      character*80                           outfile     
16
      character*80                           outfile     
17
      integer                                ntra,otim,ncol
17
      integer                                ntra,otim,ncol
18
      real                                   timeres
18
      real                                   timeres
19
      character*80                           unit
19
      character*80                           unit
20
      character*80                           mode
20
      character*80                           mode
21
 
21
 
22
c     Trajectories
22
c     Trajectories
23
      character*80                           vars(100)   
23
      character*80                           vars(100)   
24
      integer                                refdate(6)  
24
      integer                                refdate(6)  
25
      integer                                ntim       
25
      integer                                ntim       
26
      real,allocatable, dimension (:,:,:) :: trainp        
26
      real,allocatable, dimension (:,:,:) :: trainp        
27
      real,allocatable, dimension (:,:,:) :: traout        
27
      real,allocatable, dimension (:,:,:) :: traout        
28
      real,allocatable, dimension (:)     :: timold,timnew
28
      real,allocatable, dimension (:)     :: timold,timnew
29
      real,allocatable, dimension (:)     :: fldold,fldnew
29
      real,allocatable, dimension (:)     :: fldold,fldnew
30
 
30
 
31
c     Numerical constants
31
c     Numerical constants
32
      real                                   eps
32
      real                                   eps
33
      parameter                              (eps=0.001)
33
      parameter                              (eps=0.001)
34
 
34
 
35
c     Auxiliary variables
35
c     Auxiliary variables
36
      integer                                inpmode
36
      integer                                inpmode
37
      integer                                outmode
37
      integer                                outmode
38
      integer                                stat
38
      integer                                stat
39
      integer                                fid
39
      integer                                fid
40
      integer                                i,j,k
40
      integer                                i,j,k
41
      real                                   hhmm,tfrac
41
      real                                   hhmm,tfrac
42
      real                                   range
42
      real                                   range
43
 
43
 
44
c     ----------------------------------------------------------------------
44
c     ----------------------------------------------------------------------
45
c     Parameter handling
45
c     Parameter handling
46
c     ----------------------------------------------------------------------
46
c     ----------------------------------------------------------------------
47
 
47
 
48
c     Read parameters
48
c     Read parameters
49
      open(10,file='timeres.param')
49
      open(10,file='timeres.param')
50
       read(10,*) inpfile
50
       read(10,*) inpfile
51
       read(10,*) outfile
51
       read(10,*) outfile
52
       read(10,*) ntra,otim,ncol
52
       read(10,*) ntra,otim,ncol
53
       read(10,*) timeres
53
       read(10,*) timeres
54
       read(10,*) unit
54
       read(10,*) unit
55
       read(10,*) mode
55
       read(10,*) mode
56
      close(10)
56
      close(10)
57
 
57
 
58
c     Change unit to minutes
58
c     Change unit to minutes
59
      if ( unit.eq.'min') then
59
      if ( unit.eq.'min') then
60
         timeres = 1./60. * timeres
60
         timeres = 1./60. * timeres
61
         unit    = 'h'
61
         unit    = 'h'
62
      endif
62
      endif
63
 
63
 
64
c     Determine the formats
64
c     Determine the formats
65
      call mode_tra(inpmode,inpfile)
65
      call mode_tra(inpmode,inpfile)
66
      if (inpmode.eq.-1) inpmode=1
66
      if (inpmode.eq.-1) inpmode=1
67
      call mode_tra(outmode,outfile)
67
      call mode_tra(outmode,outfile)
68
      if (outmode.eq.-1) outmode=1
68
      if (outmode.eq.-1) outmode=1
69
 
69
 
70
c     ----------------------------------------------------------------------
70
c     ----------------------------------------------------------------------
71
c     Read input trajectory and allocate memory
71
c     Read input trajectory and allocate memory
72
c     ----------------------------------------------------------------------
72
c     ----------------------------------------------------------------------
73
 
73
 
74
c     Allocate memory for input trajectories
74
c     Allocate memory for input trajectories
75
      allocate(trainp(ntra,otim,ncol),stat=stat)
75
      allocate(trainp(ntra,otim,ncol),stat=stat)
76
      if (stat.ne.0) print*,'*** error allocating array trainp   ***' 
76
      if (stat.ne.0) print*,'*** error allocating array trainp   ***' 
77
      allocate(timold(otim),stat=stat)
77
      allocate(timold(otim),stat=stat)
78
      if (stat.ne.0) print*,'*** error allocating array timold   ***' 
78
      if (stat.ne.0) print*,'*** error allocating array timold   ***' 
79
      allocate(fldold(otim),stat=stat)
79
      allocate(fldold(otim),stat=stat)
80
      if (stat.ne.0) print*,'*** error allocating array fldold   ***' 
80
      if (stat.ne.0) print*,'*** error allocating array fldold   ***' 
81
 
81
 
82
c     Read inpufile
82
c     Read inpufile
83
      call ropen_tra(fid,inpfile,ntra,otim,ncol,refdate,vars,inpmode)
83
      call ropen_tra(fid,inpfile,ntra,otim,ncol,refdate,vars,inpmode)
84
      call read_tra (fid,trainp,ntra,otim,ncol,inpmode)
84
      call read_tra (fid,trainp,ntra,otim,ncol,inpmode)
85
      call close_tra(fid,inpmode)
85
      call close_tra(fid,inpmode)
86
 
86
 
87
c     Check that first four columns correspond to time,lon,lat,p
87
c     Check that first four columns correspond to time,lon,lat,p
88
      if ( (vars(1).ne.'time' ).or.
88
      if ( (vars(1).ne.'time' ).or.
89
     >     (vars(2).ne.'xpos' ).and.(vars(2).ne.'lon' ).or.
89
     >     (vars(2).ne.'xpos' ).and.(vars(2).ne.'lon' ).or.
90
     >     (vars(3).ne.'ypos' ).and.(vars(3).ne.'lat' ).or.
90
     >     (vars(3).ne.'ypos' ).and.(vars(3).ne.'lat' ).or.
91
     >     (vars(4).ne.'ppos' ).and.(vars(4).ne.'p'   ) )
91
     >     (vars(4).ne.'ppos' ).and.(vars(4).ne.'p'   ) )
92
     >then
92
     >then
93
         print*,' ERROR: problem with input trajectories ...'
93
         print*,' ERROR: problem with input trajectories ...'
94
         stop
94
         stop
95
      endif
95
      endif
96
 
96
 
97
c     Convert all times from hhmm to fractional time
97
c     Convert all times from hhmm to fractional time
98
      do i=1,ntra
98
      do i=1,ntra
99
         do j=1,otim
99
         do j=1,otim
100
            hhmm = trainp(i,j,1)
100
            hhmm = trainp(i,j,1)
101
            call hhmm2frac(hhmm,tfrac)
101
            call hhmm2frac(hhmm,tfrac)
102
            trainp(i,j,1) = tfrac
102
            trainp(i,j,1) = tfrac
103
         enddo
103
         enddo
104
      enddo
104
      enddo
105
 
105
 
106
c     Get the time range in minutes
106
c     Get the time range in minutes
107
      range = ( trainp(1,otim,1) - trainp(1,1,1) ) 
107
      range = ( trainp(1,otim,1) - trainp(1,1,1) ) 
108
 
108
 
109
c     Determine the new number of times
109
c     Determine the new number of times
110
      ntim = nint( abs( range ) / timeres ) + 1 
110
      ntim = nint( abs( range ) / timeres ) + 1 
111
 
111
 
112
c     Check that the time range and new time resolution are consistent
112
c     Check that the time range and new time resolution are consistent
113
      if ( abs( real(ntim-1) * timeres -range ).gt.eps ) then
113
      if ( abs( real(ntim-1) * timeres -range ).gt.eps ) then
114
         print*,' ERROR: time range and resolution are not compatible'
114
         print*,' ERROR: time range and resolution are not compatible'
115
         print*,'   range              = ',range
115
         print*,'   range              = ',range
116
         print*,'   (ntim-1) * timeres = ',real(ntim-1) * timeres
116
         print*,'   (ntim-1) * timeres = ',real(ntim-1) * timeres
117
         stop
117
         stop
118
      endif
118
      endif
119
 
119
 
120
c     Allocate memory for output trajectories
120
c     Allocate memory for output trajectories
121
      allocate(traout(ntra,ntim,ncol),stat=stat)
121
      allocate(traout(ntra,ntim,ncol),stat=stat)
122
      if (stat.ne.0) print*,'*** error allocating array trainp   ***' 
122
      if (stat.ne.0) print*,'*** error allocating array trainp   ***' 
123
      allocate(timnew(ntim),stat=stat)
123
      allocate(timnew(ntim),stat=stat)
124
      if (stat.ne.0) print*,'*** error allocating array timnew   ***' 
124
      if (stat.ne.0) print*,'*** error allocating array timnew   ***' 
125
      allocate(fldnew(ntim),stat=stat)
125
      allocate(fldnew(ntim),stat=stat)
126
      if (stat.ne.0) print*,'*** error allocating array fldnew   ***' 
126
      if (stat.ne.0) print*,'*** error allocating array fldnew   ***' 
127
 
127
 
128
c     Define the old and new times
128
c     Define the old and new times
129
      do i=1,otim
129
      do i=1,otim
130
         timold(i) = trainp(1,i,1)
130
         timold(i) = trainp(1,i,1)
131
      enddo
131
      enddo
132
      do i=1,ntim
132
      do i=1,ntim
133
         timnew(i) = timold(1) + real(i-1) * timeres
133
         timnew(i) = timold(1) + real(i-1) * timeres
134
      enddo
134
      enddo
135
 
135
 
136
c     ----------------------------------------------------------------------
136
c     ----------------------------------------------------------------------
137
c     Change time resolution
137
c     Change time resolution
138
c     ----------------------------------------------------------------------
138
c     ----------------------------------------------------------------------
139
 
139
 
140
      do i=1,ntra
140
      do i=1,ntra
141
      do k=2,ncol
141
      do k=2,ncol
142
 
142
 
143
c        Copy old field
143
c        Copy old field
144
         do j=1,otim
144
         do j=1,otim
145
            fldold(j) = trainp(i,j,k)
145
            fldold(j) = trainp(i,j,k)
146
         enddo
146
         enddo
147
            
147
            
148
c        Exception: Handle date line problem for longitude
148
c        Exception: Handle date line problem for longitude
149
         if ( k.eq.2 ) then 
149
         if ( k.eq.2 ) then 
150
            do j=2,otim
150
            do j=2,otim
151
               if ( (fldold(j-1)-fldold(j)).gt.180. ) then
151
               if ( (fldold(j-1)-fldold(j)).gt.180. ) then
152
                  fldold(j) = fldold(j) + 360.
152
                  fldold(j) = fldold(j) + 360.
153
               else if ( (fldold(j-1)-fldold(j)).lt.-180. ) then
153
               else if ( (fldold(j-1)-fldold(j)).lt.-180. ) then
154
                  fldold(j) = fldold(j) - 360.
154
                  fldold(j) = fldold(j) - 360.
155
               endif
155
               endif
156
            enddo
156
            enddo
157
         endif
157
         endif
158
         
158
         
159
c        Cubic spline fitting
159
c        Cubic spline fitting
160
         if ( mode.eq.'cubic' ) then
160
         if ( mode.eq.'cubic' ) then
161
            call cubicfit (timold,fldold,otim,timnew,fldnew,ntim)
161
            call cubicfit (timold,fldold,otim,timnew,fldnew,ntim)
162
         else if (mode.eq.'linear' ) then
162
         else if (mode.eq.'linear' ) then
163
            call linearfit(timold,fldold,otim,timnew,fldnew,ntim)
163
            call linearfit(timold,fldold,otim,timnew,fldnew,ntim)
164
         endif
164
         endif
165
 
165
 
166
c        Exception: Reverse date line handling for longitude
166
c        Exception: Reverse date line handling for longitude
167
         if ( k.eq.2 ) then
167
         if ( k.eq.2 ) then
168
            do j=1,ntim
168
            do j=1,ntim
169
               if ( fldnew(j).gt.180. ) then
169
               if ( fldnew(j).gt.180. ) then
170
                  fldnew(j) = fldnew(j) -360.
170
                  fldnew(j) = fldnew(j) -360.
171
               else if ( fldnew(j).lt.-180. ) then
171
               else if ( fldnew(j).lt.-180. ) then
172
                  fldnew(j) = fldnew(j) +360.
172
                  fldnew(j) = fldnew(j) +360.
173
               endif
173
               endif
174
            enddo
174
            enddo
175
         endif
175
         endif
176
 
176
 
177
c        Save the new field in the output trajectory
177
c        Save the new field in the output trajectory
178
         do j=1,ntim
178
         do j=1,ntim
179
            traout(i,j,1) = timnew(j)
179
            traout(i,j,1) = timnew(j)
180
            traout(i,j,k) = fldnew(j)
180
            traout(i,j,k) = fldnew(j)
181
         enddo
181
         enddo
182
 
182
 
183
      enddo
183
      enddo
184
      enddo
184
      enddo
185
 
185
 
186
c     ----------------------------------------------------------------------
186
c     ----------------------------------------------------------------------
187
c     Write output trajectory
187
c     Write output trajectory
188
c     ----------------------------------------------------------------------
188
c     ----------------------------------------------------------------------
189
 
189
 
190
c     Convert all times from fractional to hhmm time
190
c     Convert all times from fractional to hhmm time
191
      do i=1,ntra
191
      do i=1,ntra
192
         do j=1,ntim
192
         do j=1,ntim
193
            tfrac = traout(i,j,1)
193
            tfrac = traout(i,j,1)
194
            call frac2hhmm(tfrac,hhmm)
194
            call frac2hhmm(tfrac,hhmm)
195
            traout(i,j,1) = hhmm
195
            traout(i,j,1) = hhmm
196
         enddo
196
         enddo
197
      enddo
197
      enddo
198
    
198
    
199
c     Write output file
199
c     Write output file
200
      call wopen_tra(fid,outfile,ntra,ntim,ncol,refdate,vars,outmode)
200
      call wopen_tra(fid,outfile,ntra,ntim,ncol,refdate,vars,outmode)
201
      call write_tra(fid,traout,ntra,ntim,ncol,outmode)
201
      call write_tra(fid,traout,ntra,ntim,ncol,outmode)
202
      call close_tra(fid,outmode)
202
      call close_tra(fid,outmode)
203
      
203
      
204
      end
204
      end
205
 
205
 
206
 
206
 
207
c     ********************************************************************
207
c     ********************************************************************
208
c     * REPARAMETERIZATION SUBROUTINES                                   *
208
c     * REPARAMETERIZATION SUBROUTINES                                   *
209
c     ********************************************************************
209
c     ********************************************************************
210
 
210
 
211
c     -------------------------------------------------------------
211
c     -------------------------------------------------------------
212
c     Interpolation of the trajectory with linear interpolation
212
c     Interpolation of the trajectory with linear interpolation
213
c     -------------------------------------------------------------
213
c     -------------------------------------------------------------
214
 
214
 
215
      SUBROUTINE linearfit (time,lon,n,sptime,splon,spn)
215
      SUBROUTINE linearfit (time,lon,n,sptime,splon,spn)
216
 
216
 
217
c     Given the curve <time,lon> with <n> data points, fit a
217
c     Given the curve <time,lon> with <n> data points, fit a
218
c     linear fit to this curve. The new curve is returned in 
218
c     linear fit to this curve. The new curve is returned in 
219
c     <sptime,splon,spn> with <spn> data points. The parameter
219
c     <sptime,splon,spn> with <spn> data points. The parameter
220
c     <spn> specifies on entry the number of interpolated points
220
c     <spn> specifies on entry the number of interpolated points
221
c     along the curve.
221
c     along the curve.
222
      
222
      
223
      implicit none
223
      implicit none
224
 
224
 
225
c     Declaration of subroutine parameters
225
c     Declaration of subroutine parameters
226
      integer n
226
      integer n
227
      real    time(n),lon(n)
227
      real    time(n),lon(n)
228
      integer spn
228
      integer spn
229
      real    sptime(spn),splon(spn)
229
      real    sptime(spn),splon(spn)
230
 
230
 
231
c     Auxiliary variables
231
c     Auxiliary variables
232
      real    dt
232
      real    dt
233
      real    s
233
      real    s
234
      integer i,j,iold
234
      integer i,j,iold
235
      real    order
235
      real    order
236
 
236
 
237
c     Determine whether the input array is ascending or descending
237
c     Determine whether the input array is ascending or descending
238
      if (time(1).gt.time(n)) then
238
      if (time(1).gt.time(n)) then
239
         order=-1.
239
         order=-1.
240
      else
240
      else
241
         order= 1.
241
         order= 1.
242
      endif
242
      endif
243
 
243
 
244
c     Bring the time array into ascending order
244
c     Bring the time array into ascending order
245
      do i=1,n
245
      do i=1,n
246
         time(i)=order*time(i)
246
         time(i)=order*time(i)
247
      enddo
247
      enddo
248
 
248
 
249
c     Prepare the linear interpolation: define the new times
249
c     Prepare the linear interpolation: define the new times
250
      dt=(time(n)-time(1))/real(spn-1)
250
      dt=(time(n)-time(1))/real(spn-1)
251
      do i=1,spn
251
      do i=1,spn
252
         sptime(i)=time(1)+real(i-1)*dt
252
         sptime(i)=time(1)+real(i-1)*dt
253
      enddo
253
      enddo
254
      
254
      
255
c     Do the interpolation
255
c     Do the interpolation
256
      iold = 1
256
      iold = 1
257
      do i=1,spn
257
      do i=1,spn
258
 
258
 
259
c        Decide which interval of the old time series must be taken
259
c        Decide which interval of the old time series must be taken
260
         do j=iold,n-1
260
         do j=iold,n-1
261
            if ( ( sptime(i).ge.time(j  ) ).and.
261
            if ( ( sptime(i).ge.time(j  ) ).and.
262
     >           ( sptime(i).lt.time(j+1) ) ) 
262
     >           ( sptime(i).lt.time(j+1) ) ) 
263
     >      then
263
     >      then
264
               iold = j
264
               iold = j
265
               exit
265
               exit
266
            endif
266
            endif
267
         enddo
267
         enddo
268
         
268
         
269
c        Do the linear interpolation
269
c        Do the linear interpolation
270
         splon(i) = lon(iold) + ( lon(iold+1) - lon(iold) ) * 
270
         splon(i) = lon(iold) + ( lon(iold+1) - lon(iold) ) * 
271
     >       ( sptime(i) - time(iold) ) / ( time(iold+1) - time(iold) ) 
271
     >       ( sptime(i) - time(iold) ) / ( time(iold+1) - time(iold) ) 
272
 
272
 
273
      enddo
273
      enddo
274
 
274
 
275
c     Change the time arrays back: original order
275
c     Change the time arrays back: original order
276
      do i=1,spn
276
      do i=1,spn
277
         sptime(i)=order*sptime(i)
277
         sptime(i)=order*sptime(i)
278
      enddo
278
      enddo
279
      do i=1,n
279
      do i=1,n
280
         time(i)=order*time(i)
280
         time(i)=order*time(i)
281
      enddo
281
      enddo
282
 
282
 
283
      return
283
      return
284
      end
284
      end
285
 
285
 
286
 
286
 
287
c     -------------------------------------------------------------
287
c     -------------------------------------------------------------
288
c     Interpolation of the trajectory with a natural cubic spline
288
c     Interpolation of the trajectory with a natural cubic spline
289
c     -------------------------------------------------------------
289
c     -------------------------------------------------------------
290
 
290
 
291
      SUBROUTINE cubicfit (time,lon,n,sptime,splon,spn)
291
      SUBROUTINE cubicfit (time,lon,n,sptime,splon,spn)
292
 
292
 
293
c     Given the curve <time,lon> with <n> data points, fit a
293
c     Given the curve <time,lon> with <n> data points, fit a
294
c     cubic spline to this curve. The new curve is returned in 
294
c     cubic spline to this curve. The new curve is returned in 
295
c     <sptime,splon,spn> with <spn> data points. The parameter
295
c     <sptime,splon,spn> with <spn> data points. The parameter
296
c     <spn> specifies on entry the number of spline interpolated points
296
c     <spn> specifies on entry the number of spline interpolated points
297
c     along the curve.
297
c     along the curve.
298
      
298
      
299
      implicit none
299
      implicit none
300
 
300
 
301
c     Declaration of subroutine parameters
301
c     Declaration of subroutine parameters
302
      integer n
302
      integer n
303
      real    time(n),lon(n)
303
      real    time(n),lon(n)
304
      integer spn
304
      integer spn
305
      real    sptime(spn),splon(spn)
305
      real    sptime(spn),splon(spn)
306
 
306
 
307
c     Auxiliary variables
307
c     Auxiliary variables
308
      real    y2ax(n)
308
      real    y2ax(n)
309
      real    dt
309
      real    dt
310
      real    s
310
      real    s
311
      integer i
311
      integer i
312
      real    order
312
      real    order
313
 
313
 
314
c     Determine whether the input array is ascending or descending
314
c     Determine whether the input array is ascending or descending
315
      if (time(1).gt.time(n)) then
315
      if (time(1).gt.time(n)) then
316
         order=-1.
316
         order=-1.
317
      else
317
      else
318
         order= 1.
318
         order= 1.
319
      endif
319
      endif
320
 
320
 
321
c     Bring the time array into ascending order
321
c     Bring the time array into ascending order
322
      do i=1,n
322
      do i=1,n
323
         time(i)=order*time(i)
323
         time(i)=order*time(i)
324
      enddo
324
      enddo
325
 
325
 
326
c     Prepare the (natural) cubic spline interpolation
326
c     Prepare the (natural) cubic spline interpolation
327
      call spline (time,lon,n,1.e30,1.e30,y2ax)
327
      call spline (time,lon,n,1.e30,1.e30,y2ax)
328
      dt=(time(n)-time(1))/real(spn-1)
328
      dt=(time(n)-time(1))/real(spn-1)
329
      do i=1,spn
329
      do i=1,spn
330
         sptime(i)=time(1)+real(i-1)*dt
330
         sptime(i)=time(1)+real(i-1)*dt
331
      enddo
331
      enddo
332
      
332
      
333
c     Do the spline interpolation
333
c     Do the spline interpolation
334
      do i=1,spn
334
      do i=1,spn
335
         call splint(time,lon,y2ax,n,sptime(i),s)
335
         call splint(time,lon,y2ax,n,sptime(i),s)
336
         splon(i)=s
336
         splon(i)=s
337
      enddo
337
      enddo
338
 
338
 
339
c     Change the time arrays back
339
c     Change the time arrays back
340
      do i=1,spn
340
      do i=1,spn
341
         sptime(i)=order*sptime(i)
341
         sptime(i)=order*sptime(i)
342
      enddo
342
      enddo
343
      do i=1,n
343
      do i=1,n
344
         time(i)=order*time(i)
344
         time(i)=order*time(i)
345
      enddo
345
      enddo
346
 
346
 
347
      return
347
      return
348
      end
348
      end
349
 
349
 
350
c     -------------------------------------------------------------
350
c     -------------------------------------------------------------
351
c     Basic routines for spline interpolation (Numerical Recipes)
351
c     Basic routines for spline interpolation (Numerical Recipes)
352
c     -------------------------------------------------------------
352
c     -------------------------------------------------------------
353
 
353
 
354
      SUBROUTINE spline(x,y,n,yp1,ypn,y2)
354
      SUBROUTINE spline(x,y,n,yp1,ypn,y2)
355
      INTEGER n,NMAX
355
      INTEGER n,NMAX
356
      REAL yp1,ypn,x(n),y(n),y2(n)
356
      REAL yp1,ypn,x(n),y(n),y2(n)
357
      PARAMETER (NMAX=500)
357
      PARAMETER (NMAX=500)
358
      INTEGER i,k
358
      INTEGER i,k
359
      REAL p,qn,sig,un,u(NMAX)
359
      REAL p,qn,sig,un,u(NMAX)
360
      if (yp1.gt..99e30) then
360
      if (yp1.gt..99e30) then
361
        y2(1)=0.
361
        y2(1)=0.
362
        u(1)=0.
362
        u(1)=0.
363
      else
363
      else
364
        y2(1)=-0.5
364
        y2(1)=-0.5
365
        u(1)=(3./(x(2)-x(1)))*((y(2)-y(1))/(x(2)-x(1))-yp1)
365
        u(1)=(3./(x(2)-x(1)))*((y(2)-y(1))/(x(2)-x(1))-yp1)
366
      endif
366
      endif
367
      do 11 i=2,n-1
367
      do 11 i=2,n-1
368
        sig=(x(i)-x(i-1))/(x(i+1)-x(i-1))
368
        sig=(x(i)-x(i-1))/(x(i+1)-x(i-1))
369
        p=sig*y2(i-1)+2.
369
        p=sig*y2(i-1)+2.
370
        y2(i)=(sig-1.)/p
370
        y2(i)=(sig-1.)/p
371
        u(i)=(6.*((y(i+1)-y(i))/(x(i+
371
        u(i)=(6.*((y(i+1)-y(i))/(x(i+
372
     *1)-x(i))-(y(i)-y(i-1))/(x(i)-x(i-1)))/(x(i+1)-x(i-1))-sig*
372
     *1)-x(i))-(y(i)-y(i-1))/(x(i)-x(i-1)))/(x(i+1)-x(i-1))-sig*
373
     *u(i-1))/p
373
     *u(i-1))/p
374
11    continue
374
11    continue
375
      if (ypn.gt..99e30) then
375
      if (ypn.gt..99e30) then
376
        qn=0.
376
        qn=0.
377
        un=0.
377
        un=0.
378
      else
378
      else
379
        qn=0.5
379
        qn=0.5
380
        un=(3./(x(n)-x(n-1)))*(ypn-(y(n)-y(n-1))/(x(n)-x(n-1)))
380
        un=(3./(x(n)-x(n-1)))*(ypn-(y(n)-y(n-1))/(x(n)-x(n-1)))
381
      endif
381
      endif
382
      y2(n)=(un-qn*u(n-1))/(qn*y2(n-1)+1.)
382
      y2(n)=(un-qn*u(n-1))/(qn*y2(n-1)+1.)
383
      do 12 k=n-1,1,-1
383
      do 12 k=n-1,1,-1
384
        y2(k)=y2(k)*y2(k+1)+u(k)
384
        y2(k)=y2(k)*y2(k+1)+u(k)
385
12    continue
385
12    continue
386
      return
386
      return
387
      END
387
      END
388
 
388
 
389
      SUBROUTINE splint(xa,ya,y2a,n,x,y)
389
      SUBROUTINE splint(xa,ya,y2a,n,x,y)
390
      INTEGER n
390
      INTEGER n
391
      REAL x,y,xa(n),y2a(n),ya(n)
391
      REAL x,y,xa(n),y2a(n),ya(n)
392
      INTEGER k,khi,klo
392
      INTEGER k,khi,klo
393
      REAL a,b,h
393
      REAL a,b,h
394
      klo=1
394
      klo=1
395
      khi=n
395
      khi=n
396
1     if (khi-klo.gt.1) then
396
1     if (khi-klo.gt.1) then
397
        k=(khi+klo)/2
397
        k=(khi+klo)/2
398
        if(xa(k).gt.x)then
398
        if(xa(k).gt.x)then
399
          khi=k
399
          khi=k
400
        else
400
        else
401
          klo=k
401
          klo=k
402
        endif
402
        endif
403
      goto 1
403
      goto 1
404
      endif
404
      endif
405
      h=xa(khi)-xa(klo)
405
      h=xa(khi)-xa(klo)
406
      if (h.eq.0.) pause 'bad xa input in splint'
406
      if (h.eq.0.) pause 'bad xa input in splint'
407
      a=(xa(khi)-x)/h
407
      a=(xa(khi)-x)/h
408
      b=(x-xa(klo))/h
408
      b=(x-xa(klo))/h
409
      y=a*ya(klo)+b*ya(khi)+((a**3-a)*y2a(klo)+(b**3-b)*y2a(khi))*(h**
409
      y=a*ya(klo)+b*ya(khi)+((a**3-a)*y2a(klo)+(b**3-b)*y2a(khi))*(h**
410
     *2)/6.
410
     *2)/6.
411
      return
411
      return
412
      END
412
      END
413
    
413
    
414
 
414
 
415
      
415