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source: palm/trunk/SOURCE/fft_xy.f90 @ 17

Last change on this file since 17 was 4, checked in by raasch, 18 years ago
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1	MODULE fft_xy
2
3	!------------------------------------------------------------------------------!
4	! Actual revisions:
5	! -----------------
6	!
7	!
8	! Former revisions:
9	! -----------------
10	! $Id: fft_xy.f90 4 2007-02-13 11:33:16Z raasch $
11	! RCS Log replace by Id keyword, revision history cleaned up
12	!
13	! Revision 1.4 2006/03/28 12:27:09 raasch
14	! Stop when system-specific fft is selected on NEC. For unknown reasons this
15	! causes a program abort during first allocation in init_grid.
16	!
17	! Revision 1.2 2004/04/30 11:44:27 raasch
18	! Module renamed from fft_for_1d_decomp to fft_xy, 1d-routines renamed to
19	! fft_x and fft_y,
20	! function FFT replaced by subroutine FFTN due to problems with 64-bit
21	! mode on ibm,
22	! shape of array cwork is explicitly stored in ishape/jshape and handled
23	! to routine FFTN instead of shape-function (due to compiler error on
24	! decalpha),
25	! non vectorized FFT for nec included
26	!
27	! Revision 1.1 2002/06/11 13:00:49 raasch
28	! Initial revision
29	!
30	!
31	! Description:
32	! ------------
33	! Fast Fourier transformation along x and y for 1d domain decomposition along x.
34	! Original version: Klaus Ketelsen (May 2002)
35	!------------------------------------------------------------------------------!
36
37	USE array_kind
38	USE control_parameters
39	USE indices
40	USE singleton
41	USE temperton_fft
42
43	IMPLICIT NONE
44
45	PRIVATE
46	PUBLIC fft_x, fft_y, fft_init, fft_x_m, fft_y_m
47
48	INTEGER, DIMENSION(:), ALLOCATABLE, SAVE :: ifax_x, ifax_y
49
50	LOGICAL, SAVE :: init_fft = .FALSE.
51
52	REAL, SAVE :: sqr_nx, sqr_ny
53	REAL, DIMENSION(:), ALLOCATABLE, SAVE :: trigs_x, trigs_y
54
55	#if defined( __ibm )
56	INTEGER, PARAMETER :: nau1 = 20000, nau2 = 22000
57	!
58	!-- The following working arrays contain tables and have to be "save" and
59	!-- shared in OpenMP sense
60	REAL, DIMENSION(nau1), SAVE :: aux1, auy1, aux3, auy3
61	#elif defined( __nec )
62	INTEGER, SAVE :: nz1
63	REAL, DIMENSION(:), ALLOCATABLE, SAVE :: trig_xb, trig_xf, trig_yb, &
64	trig_yf
65	#endif
66
67	!
68	!-- Public interfaces
69	INTERFACE fft_init
70	MODULE PROCEDURE fft_init
71	END INTERFACE fft_init
72
73	INTERFACE fft_x
74	MODULE PROCEDURE fft_x
75	END INTERFACE fft_x
76
77	INTERFACE fft_y
78	MODULE PROCEDURE fft_y
79	END INTERFACE fft_y
80
81	INTERFACE fft_x_m
82	MODULE PROCEDURE fft_x_m
83	END INTERFACE fft_x_m
84
85	INTERFACE fft_y_m
86	MODULE PROCEDURE fft_y_m
87	END INTERFACE fft_y_m
88
89	CONTAINS
90
91
92	SUBROUTINE fft_init
93
94	IMPLICIT NONE
95
96	!
97	!-- The following temporary working arrays have to be on stack or private
98	!-- in OpenMP sense
99	#if defined( __ibm )
100	REAL, DIMENSION(0:nx+2) :: workx
101	REAL, DIMENSION(0:ny+2) :: worky
102	REAL, DIMENSION(nau2) :: aux2, auy2, aux4, auy4
103	#elif defined( __nec )
104	REAL, DIMENSION(0:nx+3,nz+1) :: work_x
105	REAL, DIMENSION(0:ny+3,nz+1) :: work_y
106	REAL, DIMENSION(6*(nx+3),nz+1) :: workx
107	REAL, DIMENSION(6*(ny+3),nz+1) :: worky
108	#endif
109
110	!
111	!-- Return, if already called
112	IF ( init_fft ) THEN
113	RETURN
114	ELSE
115	init_fft = .TRUE.
116	ENDIF
117
118	IF ( fft_method == 'system-specific' ) THEN
119
120	sqr_nx = SQRT( 1.0 / ( nx + 1.0 ) )
121	sqr_ny = SQRT( 1.0 / ( ny + 1.0 ) )
122	#if defined( __ibm ) && ! defined( __ibmy_special )
123	!
124	!-- Initialize tables for fft along x
125	CALL DRCFT( 1, workx, 1, workx, 1, nx+1, 1, 1, sqr_nx, aux1, nau1, &
126	aux2, nau2 )
127	CALL DCRFT( 1, workx, 1, workx, 1, nx+1, 1, -1, sqr_nx, aux3, nau1, &
128	aux4, nau2 )
129	!
130	!-- Initialize tables for fft along y
131	CALL DRCFT( 1, worky, 1, worky, 1, ny+1, 1, 1, sqr_ny, auy1, nau1, &
132	auy2, nau2 )
133	CALL DCRFT( 1, worky, 1, worky, 1, ny+1, 1, -1, sqr_ny, auy3, nau1, &
134	auy4, nau2 )
135	#elif defined( __nec )
136	PRINT*, '+++ fft_init: fft method "', fft_method, &
137	'" currently does not work on NEC'
138	CALL local_stop
139
140	ALLOCATE( trig_xb(2(nx+1)), trig_xf(2(nx+1)), &
141	trig_yb(2(ny+1)), trig_yf(2(ny+1)) )
142
143	work_x = 0.0
144	work_y = 0.0
145	nz1 = nz + MOD( nz+1, 2 ) ! odd nz slows down fft significantly
146	! when using the NEC ffts
147
148	!
149	!-- Initialize tables for fft along x (non-vector and vector case (M))
150	CALL DZFFT( 0, nx+1, sqr_nx, work_x, work_x, trig_xf, workx, 0 )
151	CALL ZDFFT( 0, nx+1, sqr_nx, work_x, work_x, trig_xb, workx, 0 )
152	CALL DZFFTM( 0, nx+1, nz1, sqr_nx, work_x, nx+4, work_x, nx+4, &
153	trig_xf, workx, 0 )
154	CALL ZDFFTM( 0, nx+1, nz1, sqr_nx, work_x, nx+4, work_x, nx+4, &
155	trig_xb, workx, 0 )
156	!
157	!-- Initialize tables for fft along y (non-vector and vector case (M))
158	CALL DZFFT( 0, ny+1, sqr_ny, work_y, work_y, trig_yf, worky, 0 )
159	CALL ZDFFT( 0, ny+1, sqr_ny, work_y, work_y, trig_yb, worky, 0 )
160	CALL DZFFTM( 0, ny+1, nz1, sqr_ny, work_y, ny+4, work_y, ny+4, &
161	trig_yf, worky, 0 )
162	CALL ZDFFTM( 0, ny+1, nz1, sqr_ny, work_y, ny+4, work_y, ny+4, &
163	trig_yb, worky, 0 )
164	#else
165	PRINT*, '+++ fft_init: no system-specific fft-call available'
166	CALL local_stop
167	#endif
168	ELSEIF ( fft_method == 'temperton-algorithm' ) THEN
169	!
170	!-- Temperton-algorithm
171	!-- Initialize tables for fft along x and y
172	ALLOCATE( ifax_x(nx+1), ifax_y(ny+1), trigs_x(nx+1), trigs_y(ny+1) )
173
174	CALL set99( trigs_x, ifax_x, nx+1 )
175	CALL set99( trigs_y, ifax_y, ny+1 )
176
177	ELSEIF ( fft_method == 'singleton-algorithm' ) THEN
178
179	CONTINUE
180
181	ELSE
182
183	PRINT*, '+++ fft_init: fft method "', fft_method, &
184	'" not available'
185	CALL local_stop
186
187	ENDIF
188
189	END SUBROUTINE fft_init
190
191
192	SUBROUTINE fft_x( ar, direction )
193
194	!----------------------------------------------------------------------!
195	! fft_x !
196	! !
197	! Fourier-transformation along x-direction !
198	! !
199	! fft_x uses internal algorithms (Singleton or Temperton) or !
200	! system-specific routines, if they are available !
201	!----------------------------------------------------------------------!
202
203	IMPLICIT NONE
204
205	CHARACTER (LEN=*) :: direction
206	INTEGER :: i, ishape(1)
207
208	!kk REAL, DIMENSION(:) :: ar !kk Does NOT work (Bug??)
209	REAL, DIMENSION(0:nx) :: ar
210	REAL, DIMENSION(0:nx+2) :: work
211	REAL, DIMENSION(nx+2) :: work1
212	COMPLEX, DIMENSION(:), ALLOCATABLE :: cwork
213	#if defined( __ibm )
214	REAL, DIMENSION(nau2) :: aux2, aux4
215	#elif defined( __nec )
216	REAL, DIMENSION(6*(nx+1)) :: work2
217	#endif
218
219	IF ( fft_method == 'singleton-algorithm' ) THEN
220
221	!
222	!-- Performing the fft with singleton's software works on every system,
223	!-- since it is part of the model
224	ALLOCATE( cwork(0:nx) )
225
226	IF ( direction == 'forward') then
227
228	DO i = 0, nx
229	cwork(i) = CMPLX( ar(i) )
230	ENDDO
231	ishape = SHAPE( cwork )
232	CALL FFTN( cwork, ishape )
233
234	DO i = 0, (nx+1)/2
235	ar(i) = REAL( cwork(i) )
236	ENDDO
237	DO i = 1, (nx+1)/2 - 1
238	ar(nx+1-i) = -AIMAG( cwork(i) )
239	ENDDO
240
241	ELSE
242
243	cwork(0) = CMPLX( ar(0), 0.0 )
244	DO i = 1, (nx+1)/2 - 1
245	cwork(i) = CMPLX( ar(i), -ar(nx+1-i) )
246	cwork(nx+1-i) = CMPLX( ar(i), ar(nx+1-i) )
247	ENDDO
248	cwork((nx+1)/2) = CMPLX( ar((nx+1)/2), 0.0 )
249
250	ishape = SHAPE( cwork )
251	CALL FFTN( cwork, ishape, inv = .TRUE. )
252
253	DO i = 0, nx
254	ar(i) = REAL( cwork(i) )
255	ENDDO
256
257	ENDIF
258
259	DEALLOCATE( cwork )
260
261	ELSEIF ( fft_method == 'temperton-algorithm' ) THEN
262
263	!
264	!-- Performing the fft with Temperton's software works on every system,
265	!-- since it is part of the model
266	IF ( direction == 'forward' ) THEN
267
268	work(0:nx) = ar
269	CALL fft991cy( work, work1, trigs_x, ifax_x, 1, nx+1, nx+1, 1, -1 )
270
271	DO i = 0, (nx+1)/2
272	ar(i) = work(2*i)
273	ENDDO
274	DO i = 1, (nx+1)/2 - 1
275	ar(nx+1-i) = work(2*i+1)
276	ENDDO
277
278	ELSE
279
280	DO i = 0, (nx+1)/2
281	work(2*i) = ar(i)
282	ENDDO
283	DO i = 1, (nx+1)/2 - 1
284	work(2*i+1) = ar(nx+1-i)
285	ENDDO
286	work(1) = 0.0
287	work(nx+2) = 0.0
288
289	CALL fft991cy( work, work1, trigs_x, ifax_x, 1, nx+1, nx+1, 1, 1 )
290	ar = work(0:nx)
291
292	ENDIF
293
294	ELSEIF ( fft_method == 'system-specific' ) THEN
295
296	#if defined( __ibm ) && ! defined( __ibmy_special )
297	IF ( direction == 'forward' ) THEN
298
299	CALL DRCFT( 0, ar, 1, work, 1, nx+1, 1, 1, sqr_nx, aux1, nau1, &
300	aux2, nau2 )
301
302	DO i = 0, (nx+1)/2
303	ar(i) = work(2*i)
304	ENDDO
305	DO i = 1, (nx+1)/2 - 1
306	ar(nx+1-i) = work(2*i+1)
307	ENDDO
308
309	ELSE
310
311	DO i = 0, (nx+1)/2
312	work(2*i) = ar(i)
313	ENDDO
314	DO i = 1, (nx+1)/2 - 1
315	work(2*i+1) = ar(nx+1-i)
316	ENDDO
317	work(1) = 0.0
318	work(nx+2) = 0.0
319
320	CALL DCRFT( 0, work, 1, work, 1, nx+1, 1, -1, sqr_nx, aux3, nau1, &
321	aux4, nau2 )
322
323	DO i = 0, nx
324	ar(i) = work(i)
325	ENDDO
326
327	ENDIF
328	#elif defined( __nec )
329	IF ( direction == 'forward' ) THEN
330
331	work(0:nx) = ar(0:nx)
332
333	CALL DZFFT( 1, nx+1, sqr_nx, work, work, trig_xf, work2, 0 )
334
335	DO i = 0, (nx+1)/2
336	ar(i) = work(2*i)
337	ENDDO
338	DO i = 1, (nx+1)/2 - 1
339	ar(nx+1-i) = work(2*i+1)
340	ENDDO
341
342	ELSE
343
344	DO i = 0, (nx+1)/2
345	work(2*i) = ar(i)
346	ENDDO
347	DO i = 1, (nx+1)/2 - 1
348	work(2*i+1) = ar(nx+1-i)
349	ENDDO
350	work(1) = 0.0
351	work(nx+2) = 0.0
352
353	CALL ZDFFT( -1, nx+1, sqr_nx, work, work, trig_xb, work2, 0 )
354
355	ar(0:nx) = work(0:nx)
356
357	ENDIF
358	#else
359	PRINT*, '+++ fft_x: no system-specific fft-call available'
360	CALL local_stop
361	#endif
362	ELSE
363
364	PRINT*, '+++ fft_x: fft method "', fft_method, '" not available'
365	CALL local_stop
366
367	ENDIF
368
369	END SUBROUTINE fft_x
370
371	SUBROUTINE fft_y( ar, direction )
372
373	!----------------------------------------------------------------------!
374	! fft_y !
375	! !
376	! Fourier-transformation along y-direction !
377	! !
378	! fft_y uses internal algorithms (Singleton or Temperton) or !
379	! system-specific routines, if they are available !
380	!----------------------------------------------------------------------!
381
382	IMPLICIT NONE
383
384	CHARACTER (LEN=*) :: direction
385	INTEGER :: j, jshape(1)
386
387	!kk REAL, DIMENSION(:) :: ar !kk Does NOT work (Bug??)
388	REAL, DIMENSION(0:ny) :: ar
389	REAL, DIMENSION(0:ny+2) :: work
390	REAL, DIMENSION(ny+2) :: work1
391	COMPLEX, DIMENSION(:), ALLOCATABLE :: cwork
392	#if defined( __ibm )
393	REAL, DIMENSION(nau2) :: auy2, auy4
394	#elif defined( __nec )
395	REAL, DIMENSION(6*(ny+1)) :: work2
396	#endif
397
398	IF ( fft_method == 'singleton-algorithm' ) THEN
399
400	!
401	!-- Performing the fft with singleton's software works on every system,
402	!-- since it is part of the model
403	ALLOCATE( cwork(0:ny) )
404
405	IF ( direction == 'forward') THEN
406
407	DO j = 0, ny
408	cwork(j) = CMPLX( ar(j) )
409	ENDDO
410
411	jshape = SHAPE( cwork )
412	CALL FFTN( cwork, jshape )
413
414	DO j = 0, (ny+1)/2
415	ar(j) = REAL( cwork(j) )
416	ENDDO
417	DO j = 1, (ny+1)/2 - 1
418	ar(ny+1-j) = -AIMAG( cwork(j) )
419	ENDDO
420
421	ELSE
422
423	cwork(0) = CMPLX( ar(0), 0.0 )
424	DO j = 1, (ny+1)/2 - 1
425	cwork(j) = CMPLX( ar(j), -ar(ny+1-j) )
426	cwork(ny+1-j) = CMPLX( ar(j), ar(ny+1-j) )
427	ENDDO
428	cwork((ny+1)/2) = CMPLX( ar((ny+1)/2), 0.0 )
429
430	jshape = SHAPE( cwork )
431	CALL FFTN( cwork, jshape, inv = .TRUE. )
432
433	DO j = 0, ny
434	ar(j) = REAL( cwork(j) )
435	ENDDO
436
437	ENDIF
438
439	DEALLOCATE( cwork )
440
441	ELSEIF ( fft_method == 'temperton-algorithm' ) THEN
442
443	!
444	!-- Performing the fft with Temperton's software works on every system,
445	!-- since it is part of the model
446	IF ( direction == 'forward' ) THEN
447
448	work(0:ny) = ar
449	CALL fft991cy( work, work1, trigs_y, ifax_y, 1, ny+1, ny+1, 1, -1 )
450
451	DO j = 0, (ny+1)/2
452	ar(j) = work(2*j)
453	ENDDO
454	DO j = 1, (ny+1)/2 - 1
455	ar(ny+1-j) = work(2*j+1)
456	ENDDO
457
458	ELSE
459
460	DO j = 0, (ny+1)/2
461	work(2*j) = ar(j)
462	ENDDO
463	DO j = 1, (ny+1)/2 - 1
464	work(2*j+1) = ar(ny+1-j)
465	ENDDO
466	work(1) = 0.0
467	work(ny+2) = 0.0
468
469	CALL fft991cy( work, work1, trigs_y, ifax_y, 1, ny+1, ny+1, 1, 1 )
470	ar = work(0:ny)
471
472	ENDIF
473
474	ELSEIF ( fft_method == 'system-specific' ) THEN
475
476	#if defined( __ibm ) && ! defined( __ibmy_special )
477	IF ( direction == 'forward') THEN
478
479	CALL DRCFT( 0, ar, 1, work, 1, ny+1, 1, 1, sqr_ny, auy1, nau1, &
480	auy2, nau2 )
481
482	DO j = 0, (ny+1)/2
483	ar(j) = work(2*j)
484	ENDDO
485	DO j = 1, (ny+1)/2 - 1
486	ar(ny+1-j) = work(2*j+1)
487	ENDDO
488
489	ELSE
490
491	DO j = 0, (ny+1)/2
492	work(2*j) = ar(j)
493	ENDDO
494	DO j = 1, (ny+1)/2 - 1
495	work(2*j+1) = ar(ny+1-j)
496	ENDDO
497	work(1) = 0.0
498	work(ny+2) = 0.0
499
500	CALL DCRFT( 0, work, 1, work, 1, ny+1, 1, -1, sqr_ny, auy3, nau1, &
501	auy4, nau2 )
502
503	DO j = 0, ny
504	ar(j) = work(j)
505	ENDDO
506
507	ENDIF
508	#elif defined( __nec )
509	IF ( direction == 'forward' ) THEN
510
511	work(0:ny) = ar(0:ny)
512
513	CALL DZFFT( 1, ny+1, sqr_ny, work, work, trig_yf, work2, 0 )
514
515	DO j = 0, (ny+1)/2
516	ar(j) = work(2*j)
517	ENDDO
518	DO j = 1, (ny+1)/2 - 1
519	ar(ny+1-j) = work(2*j+1)
520	ENDDO
521
522	ELSE
523
524	DO j = 0, (ny+1)/2
525	work(2*j) = ar(j)
526	ENDDO
527	DO j = 1, (ny+1)/2 - 1
528	work(2*j+1) = ar(ny+1-j)
529	ENDDO
530	work(1) = 0.0
531	work(ny+2) = 0.0
532
533	CALL ZDFFT( -1, ny+1, sqr_ny, work, work, trig_yb, work2, 0 )
534
535	ar(0:ny) = work(0:ny)
536
537	ENDIF
538	#else
539	PRINT*, '+++ fft_y: no system-specific fft-call available'
540	CALL local_stop
541	#endif
542
543	ELSE
544
545	PRINT*, '+++ fft_y: fft method "', fft_method, '" not available'
546	CALL local_stop
547
548	ENDIF
549
550	END SUBROUTINE fft_y
551
552	SUBROUTINE fft_x_m( ar, direction )
553
554	!----------------------------------------------------------------------!
555	! fft_x_m !
556	! !
557	! Fourier-transformation along x-direction !
558	! Version for 1d domain decomposition !
559	! using multiple 1D FFT from Math Keisan on NEC !
560	! or Temperton-algorithm !
561	! (no singleton-algorithm on NEC because it does not vectorize) !
562	! !
563	!----------------------------------------------------------------------!
564
565	IMPLICIT NONE
566
567	CHARACTER (LEN=*) :: direction
568	INTEGER :: i, k, siza, sizw
569
570	REAL, DIMENSION(0:nx,nz) :: ar
571	REAL, DIMENSION(0:nx+3,nz+1) :: ai
572	REAL, DIMENSION(6*(nx+4),nz+1) :: work1
573	#if defined( __nec )
574	COMPLEX, DIMENSION((nx+4)/2+1,nz+1) :: work
575	#endif
576
577	IF ( fft_method == 'temperton-algorithm' ) THEN
578
579	siza = SIZE( ai, 1 )
580
581	IF ( direction == 'forward') THEN
582
583	ai(0:nx,1:nz) = ar(0:nx,1:nz)
584	ai(nx+1:,:) = 0.0
585
586	CALL fft991cy( ai, work1, trigs_x, ifax_x, 1, siza, nx+1, nz, -1 )
587
588	DO k = 1, nz
589	DO i = 0, (nx+1)/2
590	ar(i,k) = ai(2*i,k)
591	ENDDO
592	DO i = 1, (nx+1)/2 - 1
593	ar(nx+1-i,k) = ai(2*i+1,k)
594	ENDDO
595	ENDDO
596
597	ELSE
598
599	DO k = 1, nz
600	DO i = 0, (nx+1)/2
601	ai(2*i,k) = ar(i,k)
602	ENDDO
603	DO i = 1, (nx+1)/2 - 1
604	ai(2*i+1,k) = ar(nx+1-i,k)
605	ENDDO
606	ai(1,k) = 0.0
607	ai(nx+2,k) = 0.0
608	ENDDO
609
610	CALL fft991cy( ai, work1, trigs_x, ifax_x, 1, siza, nx+1, nz, 1 )
611
612	ar(0:nx,1:nz) = ai(0:nx,1:nz)
613
614	ENDIF
615
616	ELSEIF ( fft_method == 'system-specific' ) THEN
617
618	#if defined( __nec )
619	siza = SIZE( ai, 1 )
620	sizw = SIZE( work, 1 )
621
622	IF ( direction == 'forward') THEN
623
624	!
625	!-- Tables are initialized once more. This call should not be
626	!-- necessary, but otherwise program aborts in asymmetric case
627	CALL DZFFTM( 0, nx+1, nz1, sqr_nx, work, nx+4, work, nx+4, &
628	trig_xf, work1, 0 )
629
630	ai(0:nx,1:nz) = ar(0:nx,1:nz)
631	IF ( nz1 > nz ) THEN
632	ai(:,nz1) = 0.0
633	ENDIF
634
635	CALL DZFFTM( 1, nx+1, nz1, sqr_nx, ai, siza, work, sizw, &
636	trig_xf, work1, 0 )
637
638	DO k = 1, nz
639	DO i = 0, (nx+1)/2
640	ar(i,k) = REAL( work(i+1,k) )
641	ENDDO
642	DO i = 1, (nx+1)/2 - 1
643	ar(nx+1-i,k) = AIMAG( work(i+1,k) )
644	ENDDO
645	ENDDO
646
647	ELSE
648
649	!
650	!-- Tables are initialized once more. This call should not be
651	!-- necessary, but otherwise program aborts in asymmetric case
652	CALL ZDFFTM( 0, nx+1, nz1, sqr_nx, work, nx+4, work, nx+4, &
653	trig_xb, work1, 0 )
654
655	IF ( nz1 > nz ) THEN
656	work(:,nz1) = 0.0
657	ENDIF
658	DO k = 1, nz
659	work(1,k) = CMPLX( ar(0,k), 0.0 )
660	DO i = 1, (nx+1)/2 - 1
661	work(i+1,k) = CMPLX( ar(i,k), ar(nx+1-i,k) )
662	ENDDO
663	work(((nx+1)/2)+1,k) = CMPLX( ar((nx+1)/2,k), 0.0 )
664	ENDDO
665
666	CALL ZDFFTM( -1, nx+1, nz1, sqr_nx, work, sizw, ai, siza, &
667	trig_xb, work1, 0 )
668
669	ar(0:nx,1:nz) = ai(0:nx,1:nz)
670
671	ENDIF
672
673	#else
674	PRINT*, '+++ fft_x_m: no system-specific fft-call available'
675	STOP
676	#endif
677
678	ELSE
679
680	PRINT*, '+++ fft_x_m: fft method "', fft_method, '" not available'
681	CALL local_stop
682
683	ENDIF
684
685	END SUBROUTINE fft_x_m
686
687	SUBROUTINE fft_y_m( ar, ny1, direction )
688
689	!----------------------------------------------------------------------!
690	! fft_y_m !
691	! !
692	! Fourier-transformation along y-direction !
693	! Version for 1d domain decomposition !
694	! using multiple 1D FFT from Math Keisan on NEC !
695	! or Temperton-algorithm !
696	! (no singleton-algorithm on NEC because it does not vectorize) !
697	! !
698	!----------------------------------------------------------------------!
699
700	IMPLICIT NONE
701
702	CHARACTER (LEN=*) :: direction
703	INTEGER :: j, k, ny1, siza, sizw
704
705	REAL, DIMENSION(0:ny1,nz) :: ar
706	REAL, DIMENSION(0:ny+3,nz+1) :: ai
707	REAL, DIMENSION(6*(ny+4),nz+1) :: work1
708	#if defined( __nec )
709	COMPLEX, DIMENSION((ny+4)/2+1,nz+1) :: work
710	#endif
711
712	IF ( fft_method == 'temperton-algorithm' ) THEN
713
714	siza = SIZE( ai, 1 )
715
716	IF ( direction == 'forward') THEN
717
718	ai(0:ny,1:nz) = ar(0:ny,1:nz)
719	ai(ny+1:,:) = 0.0
720
721	CALL fft991cy( ai, work1, trigs_y, ifax_y, 1, siza, ny+1, nz, -1 )
722
723	DO k = 1, nz
724	DO j = 0, (ny+1)/2
725	ar(j,k) = ai(2*j,k)
726	ENDDO
727	DO j = 1, (ny+1)/2 - 1
728	ar(ny+1-j,k) = ai(2*j+1,k)
729	ENDDO
730	ENDDO
731
732	ELSE
733
734	DO k = 1, nz
735	DO j = 0, (ny+1)/2
736	ai(2*j,k) = ar(j,k)
737	ENDDO
738	DO j = 1, (ny+1)/2 - 1
739	ai(2*j+1,k) = ar(ny+1-j,k)
740	ENDDO
741	ai(1,k) = 0.0
742	ai(ny+2,k) = 0.0
743	ENDDO
744
745	CALL fft991cy( ai, work1, trigs_y, ifax_y, 1, siza, ny+1, nz, 1 )
746
747	ar(0:ny,1:nz) = ai(0:ny,1:nz)
748
749	ENDIF
750
751	ELSEIF ( fft_method == 'system-specific' ) THEN
752
753	#if defined( __nec )
754	siza = SIZE( ai, 1 )
755	sizw = SIZE( work, 1 )
756
757	IF ( direction == 'forward') THEN
758
759	!
760	!-- Tables are initialized once more. This call should not be
761	!-- necessary, but otherwise program aborts in asymmetric case
762	CALL DZFFTM( 0, ny+1, nz1, sqr_ny, work, ny+4, work, ny+4, &
763	trig_yf, work1, 0 )
764
765	ai(0:ny,1:nz) = ar(0:ny,1:nz)
766	IF ( nz1 > nz ) THEN
767	ai(:,nz1) = 0.0
768	ENDIF
769
770	CALL DZFFTM( 1, ny+1, nz1, sqr_ny, ai, siza, work, sizw, &
771	trig_yf, work1, 0 )
772
773	DO k = 1, nz
774	DO j = 0, (ny+1)/2
775	ar(j,k) = REAL( work(j+1,k) )
776	ENDDO
777	DO j = 1, (ny+1)/2 - 1
778	ar(ny+1-j,k) = AIMAG( work(j+1,k) )
779	ENDDO
780	ENDDO
781
782	ELSE
783
784	!
785	!-- Tables are initialized once more. This call should not be
786	!-- necessary, but otherwise program aborts in asymmetric case
787	CALL ZDFFTM( 0, ny+1, nz1, sqr_ny, work, ny+4, work, ny+4, &
788	trig_yb, work1, 0 )
789
790	IF ( nz1 > nz ) THEN
791	work(:,nz1) = 0.0
792	ENDIF
793	DO k = 1, nz
794	work(1,k) = CMPLX( ar(0,k), 0.0 )
795	DO j = 1, (ny+1)/2 - 1
796	work(j+1,k) = CMPLX( ar(j,k), ar(ny+1-j,k) )
797	ENDDO
798	work(((ny+1)/2)+1,k) = CMPLX( ar((ny+1)/2,k), 0.0 )
799	ENDDO
800
801	CALL ZDFFTM( -1, ny+1, nz1, sqr_ny, work, sizw, ai, siza, &
802	trig_yb, work1, 0 )
803
804	ar(0:ny,1:nz) = ai(0:ny,1:nz)
805
806	ENDIF
807
808	#else
809	PRINT*, '+++ fft_y_m: no system-specific fft-call available'
810	STOP
811	#endif
812
813	ELSE
814
815	PRINT*, '+++ fft_y_m: fft method "', fft_method, '" not available'
816	CALL local_stop
817
818	ENDIF
819
820	END SUBROUTINE fft_y_m
821
822	END MODULE fft_xy

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