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source: palm/trunk/SOURCE/random_generator_parallel.f90 @ 1787

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1	!> @file random_generator_parallel.f90
2	!------------------------------------------------------------------------------!
3	! This file is part of PALM.
4	!
5	! PALM is free software: you can redistribute it and/or modify it under the terms
6	! of the GNU General Public License as published by the Free Software Foundation,
7	! either version 3 of the License, or (at your option) any later version.
8	!
9	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
10	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
11	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
12	!
13	! You should have received a copy of the GNU General Public License along with
14	! PALM. If not, see <http://www.gnu.org/licenses/>.
15	!
16	! Copyright 1997-2014 Leibniz Universitaet Hannover
17	!------------------------------------------------------------------------------!
18	!
19	! Current revisions:
20	! -----------------
21	!
22	!
23	! Former revisions:
24	! -----------------
25	! $Id: random_generator_parallel.f90 1683 2015-10-07 23:57:51Z raasch $
26	!
27	! 1682 2015-10-07 23:56:08Z knoop
28	! Code annotations made doxygen readable
29	!
30	! 1400 2014-05-09 14:03:54Z knoop
31	! Initial revision
32	!
33	!
34	! Description:
35	! ------------
36	!> This module contains and supports the random number generating routine ran_parallel.
37	!> ran_parallel returns a uniform random deviate between 0.0 and 1.0
38	!> (exclusive of the end point values).
39	!> Additionally it provides the generator with five integer for use as initial state space.
40	!> The first tree integers (iran, jran, kran) are maintained as non negative values,
41	!> while the last two (mran, nran) have 32-bit nonzero values.
42	!> Also provided by this module is support for initializing or reinitializing
43	!> the state space to a desired standard sequence number, hashing the initial
44	!> values to random values, and allocating and deallocating the internal workspace
45	!> Random number generator, produces numbers equally distributed in interval
46	!>
47	!> This routine is taken from the "numerical recipies vol. 2"
48	!------------------------------------------------------------------------------!
49	MODULE random_generator_parallel
50
51
52	USE kinds
53
54	IMPLICIT NONE
55
56	PRIVATE
57	PUBLIC random_number_parallel, random_seed_parallel, random_dummy, &
58	id_random_array, seq_random_array
59
60	INTEGER(isp), SAVE :: lenran=0 !<
61	INTEGER(isp), SAVE :: seq=0 !<
62	INTEGER(isp), SAVE :: iran0 !<
63	INTEGER(isp), SAVE :: jran0 !<
64	INTEGER(isp), SAVE :: kran0 !<
65	INTEGER(isp), SAVE :: mran0 !<
66	INTEGER(isp), SAVE :: nran0 !<
67	INTEGER(isp), SAVE :: rans !<
68
69	INTEGER(isp), DIMENSION(:, :), POINTER, SAVE :: ranseeds !<
70
71	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: iran !<
72	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: jran !<
73	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: kran !<
74	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: mran !<
75	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: nran !<
76	INTEGER(isp), DIMENSION(:), POINTER, SAVE :: ranv !<
77
78
79
80	INTEGER(isp), DIMENSION(:,:), ALLOCATABLE :: id_random_array !<
81	INTEGER(isp), DIMENSION(:,:,:), ALLOCATABLE :: seq_random_array !<
82
83	REAL(wp), SAVE :: amm !<
84
85	REAL(wp) :: random_dummy=0.0 !<
86
87	INTERFACE random_number_parallel
88	MODULE PROCEDURE ran0_s
89	END INTERFACE
90
91	INTERFACE random_seed_parallel
92	MODULE PROCEDURE random_seed_parallel
93	END INTERFACE
94
95	INTERFACE ran_hash
96	MODULE PROCEDURE ran_hash_v
97	END INTERFACE
98
99	INTERFACE reallocate
100	MODULE PROCEDURE reallocate_iv,reallocate_im
101	END INTERFACE
102
103	INTERFACE arth
104	MODULE PROCEDURE arth_i
105	END INTERFACE
106
107	CONTAINS
108
109	!------------------------------------------------------------------------------!
110	! Description:
111	! ------------
112	!> Lagged Fibonacci generator combined with a Marsaglia shiftsequence.
113	!> Returns as harvest a uniform random deviate between 0.0 and 1.0 (exclusive of the end point values).
114	!> This generator has the same calling and initialization conventions as Fortran 90's random_number routine.
115	!> Use random_seed_parallel to initialize or reinitialize to a particular sequence.
116	!> The period of this generator is about 2.0 x 10^28, and it fully vectorizes.
117	!> Validity of the integer model assumed by this generator is tested at initialization.
118	!------------------------------------------------------------------------------!
119	SUBROUTINE ran0_s(harvest)
120
121	USE kinds
122
123	IMPLICIT NONE
124
125	REAL(wp), INTENT(OUT) :: harvest !<
126
127	IF (lenran < 1) CALL ran_init(1) !- Initialization routine in ran_state.
128
129	!- Update Fibonacci generator, which has period p^2 + p + 1, p = 2^31 - 69.
130	rans = iran0 - kran0
131
132	IF (rans < 0) rans = rans + 2147483579_isp
133
134	iran0 = jran0
135	jran0 = kran0
136	kran0 = rans
137
138	nran0 = ieor( nran0, ishft (nran0, 13) ) !- Update Marsaglia shift sequence with period 2^32 - 1.
139	nran0 = ieor( nran0, ishft (nran0, -17) )
140	nran0 = ieor( nran0, ishft (nran0, 5) )
141
142	rans = ieor( nran0, rans ) !- Combine the generators.
143
144	harvest = amm * merge( rans, not(rans), rans < 0 ) !- Make the result positive definite (note that amm is negative).
145
146	END SUBROUTINE ran0_s
147
148	!------------------------------------------------------------------------------!
149	! Description:
150	! ------------
151	!> Initialize or reinitialize the random generator state space to vectors of size length.
152	!> The saved variable seq is hashed (via calls to the module routine ran_hash)
153	!> to create unique starting seeds, different for each vector component.
154	!------------------------------------------------------------------------------!
155	SUBROUTINE ran_init( length )
156
157	USE kinds
158
159	IMPLICIT NONE
160
161	INTEGER(isp), INTENT(IN) :: length !<
162
163	INTEGER(isp), PARAMETER:: hg=huge(1_isp) !<
164	INTEGER(isp), PARAMETER:: hgm=-hg !<
165	INTEGER(isp), PARAMETER:: hgng=hgm-1 !<
166
167	INTEGER(isp) :: new !<
168	INTEGER(isp) :: j !<
169	INTEGER(isp) :: hgt !<
170
171	IF ( length < lenran ) RETURN !- Simply return if enough space is already allocated.
172
173	hgt = hg
174
175	!- The following lines check that kind value isp is in fact a 32-bit integer
176	!- with the usual properties that we expect it to have (under negation and wrap-around addition).
177	!- If all of these tests are satisfied, then the routines that use this module are portable,
178	!- even though they go beyond Fortran 90's integer model.
179
180	IF ( hg /= 2147483647 ) CALL ran_error('ran_init: arith assump 1 fails')
181	IF ( hgng >= 0 ) CALL ran_error('ran_init: arith assump 2 fails')
182	IF ( hgt+1 /= hgng ) CALL ran_error('ran_init: arith assump 3 fails')
183	IF ( not(hg) >= 0 ) CALL ran_error('ran_init: arith assump 4 fails')
184	IF ( not(hgng) < 0 ) CALL ran_error('ran_init: arith assump 5 fails')
185	IF ( hg+hgng >= 0 ) CALL ran_error('ran_init: arith assump 6 fails')
186	IF ( not(-1_isp) < 0 ) CALL ran_error('ran_init: arith assump 7 fails')
187	IF ( not(0_isp) >= 0 ) CALL ran_error('ran_init: arith assump 8 fails')
188	IF ( not(1_isp) >= 0 ) CALL ran_error('ran_init: arith assump 9 fails')
189
190	IF ( lenran > 0) THEN !- Reallocate space, or ...
191
192	ranseeds => reallocate( ranseeds, length, 5)
193	ranv => reallocate( ranv, length-1)
194	new = lenran+1
195
196	ELSE !- allocate space.
197
198	ALLOCATE(ranseeds(length,5))
199	ALLOCATE(ranv(length-1))
200	new = 1 !- Index of first location not yet initialized.
201	amm = nearest(1.0_wp,-1.0_wp)/hgng
202	!- Use of nearest is to ensure that returned random deviates are strictly lessthan 1.0.
203	IF (ammhgng >= 1.0 .or. ammhgng <= 0.0) &
204	CALL ran_error('ran_init: arith assump 10 fails')
205
206	END IF
207
208	!- Set starting values, unique by seq and vector component.
209	ranseeds(new:,1) = seq
210	ranseeds(new:,2:5)=spread(arth(new,1,size(ranseeds(new:,1))),2,4)
211
212	DO j=1,4 !- Hash them.
213	CALL ran_hash(ranseeds(new:,j), ranseeds(new:,j+1))
214	END DO
215
216	WHERE (ranseeds (new: ,1:3) < 0) &
217	ranseeds(new: ,1:3)=not(ranseeds(new: ,1:3)) !- Enforce nonnegativity.
218
219	WHERE (ranseeds(new: ,4:5) == 0) ranseeds(new: ,4:5)=1 !- Enforce nonzero.
220
221	IF (new == 1) THEN !- Set scalar seeds.
222
223	iran0 = ranseeds(1,1)
224	jran0 = ranseeds(1,2)
225	kran0 = ranseeds(1,3)
226	mran0 = ranseeds(1,4)
227	nran0 = ranseeds(1,5)
228	rans = nran0
229
230	END IF
231
232	IF (length > 1) THEN !- Point to vector seeds.
233
234	iran => ranseeds(2:,1)
235	jran => ranseeds(2:,2)
236	kran => ranseeds(2:,3)
237	mran => ranseeds(2:,4)
238	nran => ranseeds(2:,5)
239	ranv = nran
240
241	END IF
242
243	lenran = length
244
245	END SUBROUTINE ran_init
246
247	!------------------------------------------------------------------------------!
248	! Description:
249	! ------------
250	!> User interface to release the workspace used by the random number routines.
251	!------------------------------------------------------------------------------!
252	SUBROUTINE ran_deallocate
253
254	IF ( lenran > 0 ) THEN
255
256	DEALLOCATE(ranseeds, ranv)
257	NULLIFY(ranseeds, ranv, iran, jran, kran, mran, nran)
258	lenran = 0
259
260	END IF
261
262	END SUBROUTINE ran_deallocate
263
264	!------------------------------------------------------------------------------!
265	! Description:
266	! ------------
267	!> User interface for seeding the random number routines.
268	!> Syntax is exactly like Fortran 90's random_seed routine,
269	!> with one additional argument keyword: random_sequence, set to any integer
270	!> value, causes an immediate new initialization, seeded by that integer.
271	!------------------------------------------------------------------------------!
272	SUBROUTINE random_seed_parallel( random_sequence, state_size, put, get )
273
274	IMPLICIT NONE
275
276	INTEGER(isp), OPTIONAL, INTENT(IN) :: random_sequence !<
277	INTEGER(isp), OPTIONAL, INTENT(OUT) :: state_size !<
278
279	INTEGER(isp), DIMENSION(:), OPTIONAL, INTENT(IN) :: put !<
280	INTEGER(isp), DIMENSION(:), OPTIONAL, INTENT(OUT) :: get !<
281
282	IF ( present(state_size) ) THEN
283
284	state_size = 5 * lenran
285
286	ELSE IF ( present(put) ) THEN
287
288	IF ( lenran == 0 ) RETURN
289
290	ranseeds = reshape( put,shape(ranseeds) )
291
292	WHERE (ranseeds(:,1:3) < 0) ranseeds(: ,1:3) = not(ranseeds(: ,1:3))
293	!- Enforce nonnegativity and nonzero conditions on any user-supplied seeds.
294
295	WHERE (ranseeds(:,4:5) == 0) ranseeds(:,4:5) = 1
296
297	iran0 = ranseeds(1,1)
298	jran0 = ranseeds(1,2)
299	kran0 = ranseeds(1,3)
300	mran0 = ranseeds(1,4)
301	nran0 = ranseeds(1,5)
302
303	ELSE IF ( present(get) ) THEN
304
305	IF (lenran == 0) RETURN
306
307	ranseeds(1,1:5) = (/ iran0,jran0,kran0,mran0,nran0 /)
308	get = reshape( ranseeds, shape(get) )
309
310	ELSE IF ( present(random_sequence) ) THEN
311
312	CALL ran_deallocate
313	seq = random_sequence
314
315	END IF
316
317	END SUBROUTINE random_seed_parallel
318
319	!------------------------------------------------------------------------------!
320	! Description:
321	! ------------
322	!> DES-like hashing of two 32-bit integers, using shifts,
323	!> xor's, and adds to make the internal nonlinear function.
324	!------------------------------------------------------------------------------!
325	SUBROUTINE ran_hash_v( il, ir )
326
327	IMPLICIT NONE
328
329	INTEGER(isp), DIMENSION(:), INTENT(INOUT) :: il !<
330	INTEGER(isp), DIMENSION(:), INTENT(INOUT) :: ir !<
331
332	INTEGER(isp), DIMENSION(size(il)) :: is !<
333
334	INTEGER(isp) :: j !<
335
336	DO j=1,4
337
338	is = ir
339	ir = ieor( ir, ishft(ir,5) ) + 1422217823
340	ir = ieor( ir, ishft(ir,-16) ) + 1842055030
341	ir = ieor( ir, ishft(ir,9) ) + 80567781
342	ir = ieor( il, ir )
343	il = is
344	END DO
345
346	END SUBROUTINE ran_hash_v
347
348	!------------------------------------------------------------------------------!
349	! Description:
350	! ------------
351	!> User interface to process error-messages
352	!> produced by the random_number_parallel module
353	!------------------------------------------------------------------------------!
354	SUBROUTINE ran_error(string)
355
356	CHARACTER(LEN=*), INTENT(IN) :: string !<
357
358	write (,) 'Error in module random_number_parallel: ',string
359
360	STOP 'Program terminated by ran_error'
361
362	END SUBROUTINE ran_error
363
364	!------------------------------------------------------------------------------!
365	! Description:
366	! ------------
367	!> Reallocates the generators state space "ranseeds" to vectors of size length.
368	!------------------------------------------------------------------------------!
369	FUNCTION reallocate_iv( p, n )
370
371	INTEGER(isp), DIMENSION(:), POINTER :: p !<
372	INTEGER(isp), DIMENSION(:), POINTER :: reallocate_iv !<
373
374	INTEGER(isp), INTENT(IN) :: n !<
375
376	INTEGER(isp) :: nold !<
377	INTEGER(isp) :: ierr !<
378
379	ALLOCATE(reallocate_iv(n),stat=ierr)
380
381	IF (ierr /= 0) CALL &
382	ran_error('reallocate_iv: problem in attempt to allocate memory')
383
384	IF (.not. associated(p)) RETURN
385
386	nold = size(p)
387
388	reallocate_iv(1:min(nold,n)) = p(1:min(nold,n))
389
390	DEALLOCATE(p)
391
392	END FUNCTION reallocate_iv
393
394	FUNCTION reallocate_im( p, n, m )
395
396	INTEGER(isp), DIMENSION(:,:), POINTER :: p !<
397	INTEGER(isp), DIMENSION(:,:), POINTER :: reallocate_im !<
398
399	INTEGER(isp), INTENT(IN) :: m !<
400	INTEGER(isp), INTENT(IN) :: n !<
401
402	INTEGER(isp) :: mold !<
403	INTEGER(isp) :: nold !<
404	INTEGER(isp) :: ierr !<
405
406	ALLOCATE(reallocate_im(n,m),stat=ierr)
407
408	IF (ierr /= 0) CALL &
409	ran_error('reallocate_im: problem in attempt to allocate memory')
410
411	IF (.not. associated(p)) RETURN
412
413	nold = size(p,1)
414	mold = size(p,2)
415
416	reallocate_im(1:min(nold,n),1:min(mold,m)) = &
417	p(1:min(nold,n),1:min(mold,m))
418
419	DEALLOCATE(p)
420
421	END FUNCTION reallocate_im
422
423	!------------------------------------------------------------------------------!
424	! Description:
425	! ------------
426	!> Reallocates the generators state space "ranseeds" to vectors of size length.
427	!------------------------------------------------------------------------------!
428	FUNCTION arth_i(first,increment,n)
429
430	INTEGER(isp), INTENT(IN) :: first !<
431	INTEGER(isp), INTENT(IN) :: increment !<
432	INTEGER(isp), INTENT(IN) :: n !<
433
434	INTEGER(isp), DIMENSION(n) :: arth_i !<
435
436	INTEGER(isp) :: k !<
437	INTEGER(isp) :: k2 !<
438	INTEGER(isp) :: temp !<
439
440	INTEGER(isp), PARAMETER :: npar_arth=16 !<
441	INTEGER(isp), PARAMETER :: npar2_arth=8 !<
442
443	IF (n > 0) arth_i(1) = first
444
445	IF (n <= npar_arth) THEN
446
447	DO k=2,n
448	arth_i(k) = arth_i(k-1)+increment
449	END DO
450
451	ELSE
452
453	DO k=2,npar2_arth
454	arth_i(k) = arth_i(k-1) + increment
455	END DO
456
457	temp = increment * npar2_arth
458	k = npar2_arth
459
460	DO
461	IF (k >= n) EXIT
462	k2 = k + k
463	arth_i(k+1:min(k2,n)) = temp + arth_i(1:min(k,n-k))
464	temp = temp + temp
465	k = k2
466	END DO
467
468	END IF
469
470	END FUNCTION arth_i
471
472	END MODULE random_generator_parallel

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