elpa2_utilities.F90 23.2 KB
Newer Older
1
2
3
4
5
!    This file is part of ELPA.
!
!    The ELPA library was originally created by the ELPA consortium,
!    consisting of the following organizations:
!
6
7
!    - Max Planck Computing and Data Facility (MPCDF), formerly known as
!      Rechenzentrum Garching der Max-Planck-Gesellschaft (RZG),
8
9
10
11
12
13
14
15
16
17
18
19
!    - Bergische Universität Wuppertal, Lehrstuhl für angewandte
!      Informatik,
!    - Technische Universität München, Lehrstuhl für Informatik mit
!      Schwerpunkt Wissenschaftliches Rechnen ,
!    - Fritz-Haber-Institut, Berlin, Abt. Theorie,
!    - Max-Plack-Institut für Mathematik in den Naturwissenschaftrn,
!      Leipzig, Abt. Komplexe Strukutren in Biologie und Kognition,
!      and
!    - IBM Deutschland GmbH
!
!
!    More information can be found here:
20
!    http://elpa.mpcdf.mpg.de/
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
!
!    ELPA is free software: you can redistribute it and/or modify
!    it under the terms of the version 3 of the license of the
!    GNU Lesser General Public License as published by the Free
!    Software Foundation.
!
!    ELPA is distributed in the hope that it will be useful,
!    but WITHOUT ANY WARRANTY; without even the implied warranty of
!    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
!    GNU Lesser General Public License for more details.
!
!    You should have received a copy of the GNU Lesser General Public License
!    along with ELPA.  If not, see <http://www.gnu.org/licenses/>
!
!    ELPA reflects a substantial effort on the part of the original
!    ELPA consortium, and we ask you to respect the spirit of the
!    license that we chose: i.e., please contribute any changes you
!    may have back to the original ELPA library distribution, and keep
!    any derivatives of ELPA under the same license that we chose for
!    the original distribution, the GNU Lesser General Public License.
!
!
! ELPA1 -- Faster replacements for ScaLAPACK symmetric eigenvalue routines
!
! Copyright of the original code rests with the authors inside the ELPA
! consortium. The copyright of any additional modifications shall rest
! with their original authors, but shall adhere to the licensing terms
! distributed along with the original code in the file "COPYING".



! ELPA2 -- 2-stage solver for ELPA
!
! Copyright of the original code rests with the authors inside the ELPA
! consortium. The copyright of any additional modifications shall rest
! with their original authors, but shall adhere to the licensing terms
! distributed along with the original code in the file "COPYING".


#include "config-f90.h"
Andreas Marek's avatar
Andreas Marek committed
61
#include <elpa/elpa_kernel_constants.h>
62
63

module ELPA2_utilities
64
  use ELPA_utilities
65
66
67
68
69
70
71
72
73
  implicit none

  PRIVATE ! By default, all routines contained are private

  ! The following routines are public:

  public :: get_actual_real_kernel_name, get_actual_complex_kernel_name
  public :: REAL_ELPA_KERNEL_GENERIC, REAL_ELPA_KERNEL_GENERIC_SIMPLE, &
            REAL_ELPA_KERNEL_BGP, REAL_ELPA_KERNEL_BGQ,                &
74
75
            REAL_ELPA_KERNEL_SSE, REAL_ELPA_KERNEL_SSE_BLOCK2,         &
            REAL_ELPA_KERNEL_SSE_BLOCK4, REAL_ELPA_KERNEL_SSE_BLOCK6,  &
76
77
78
79
            REAL_ELPA_KERNEL_AVX_BLOCK2,                               &
            REAL_ELPA_KERNEL_AVX_BLOCK4, REAL_ELPA_KERNEL_AVX_BLOCK6,  &
            REAL_ELPA_KERNEL_AVX2_BLOCK2,                              &
            REAL_ELPA_KERNEL_AVX2_BLOCK4, REAL_ELPA_KERNEL_AVX2_BLOCK6
80
81
82

  public :: COMPLEX_ELPA_KERNEL_GENERIC, COMPLEX_ELPA_KERNEL_GENERIC_SIMPLE, &
            COMPLEX_ELPA_KERNEL_BGP, COMPLEX_ELPA_KERNEL_BGQ,                &
83
84
            COMPLEX_ELPA_KERNEL_SSE, COMPLEX_ELPA_KERNEL_SSE_BLOCK1,         &
            COMPLEX_ELPA_KERNEL_SSE_BLOCK2,                                  &
85
86
            COMPLEX_ELPA_KERNEL_AVX_BLOCK1,COMPLEX_ELPA_KERNEL_AVX_BLOCK2,   &
            COMPLEX_ELPA_KERNEL_AVX2_BLOCK1,COMPLEX_ELPA_KERNEL_AVX2_BLOCK2
87
88
89
90
91
92
93
94
95
96

  public :: REAL_ELPA_KERNEL_NAMES, COMPLEX_ELPA_KERNEL_NAMES

  public :: get_actual_complex_kernel, get_actual_real_kernel

  public :: check_allowed_complex_kernels, check_allowed_real_kernels

  public :: AVAILABLE_COMPLEX_ELPA_KERNELS, AVAILABLE_REAL_ELPA_KERNELS

  public :: print_available_real_kernels, print_available_complex_kernels
97
  public :: query_available_real_kernels, query_available_complex_kernels
98
99
100

  public :: qr_decomposition_via_environment_variable

Andreas Marek's avatar
Andreas Marek committed
101
102
103
104
105
106
  integer, parameter :: number_of_real_kernels           = ELPA2_NUMBER_OF_REAL_KERNELS
  integer, parameter :: REAL_ELPA_KERNEL_GENERIC         = ELPA2_REAL_KERNEL_GENERIC
  integer, parameter :: REAL_ELPA_KERNEL_GENERIC_SIMPLE  = ELPA2_REAL_KERNEL_GENERIC_SIMPLE
  integer, parameter :: REAL_ELPA_KERNEL_BGP             = ELPA2_REAL_KERNEL_BGP
  integer, parameter :: REAL_ELPA_KERNEL_BGQ             = ELPA2_REAL_KERNEL_BGQ
  integer, parameter :: REAL_ELPA_KERNEL_SSE             = ELPA2_REAL_KERNEL_SSE
107
108
109
  integer, parameter :: REAL_ELPA_KERNEL_SSE_BLOCK2      = ELPA2_REAL_KERNEL_SSE_BLOCK2
  integer, parameter :: REAL_ELPA_KERNEL_SSE_BLOCK4      = ELPA2_REAL_KERNEL_SSE_BLOCK4
  integer, parameter :: REAL_ELPA_KERNEL_SSE_BLOCK6      = ELPA2_REAL_KERNEL_SSE_BLOCK6
Andreas Marek's avatar
Andreas Marek committed
110
111
112
  integer, parameter :: REAL_ELPA_KERNEL_AVX_BLOCK2      = ELPA2_REAL_KERNEL_AVX_BLOCK2
  integer, parameter :: REAL_ELPA_KERNEL_AVX_BLOCK4      = ELPA2_REAL_KERNEL_AVX_BLOCK4
  integer, parameter :: REAL_ELPA_KERNEL_AVX_BLOCK6      = ELPA2_REAL_KERNEL_AVX_BLOCK6
113
114
115
  integer, parameter :: REAL_ELPA_KERNEL_AVX2_BLOCK2     = ELPA2_REAL_KERNEL_AVX2_BLOCK2
  integer, parameter :: REAL_ELPA_KERNEL_AVX2_BLOCK4     = ELPA2_REAL_KERNEL_AVX2_BLOCK4
  integer, parameter :: REAL_ELPA_KERNEL_AVX2_BLOCK6     = ELPA2_REAL_KERNEL_AVX2_BLOCK6
116
117
118
119
120
121
122
123
124
125
126
127

#if defined(WITH_REAL_AVX_BLOCK2_KERNEL)
  integer, parameter :: DEFAULT_REAL_ELPA_KERNEL = REAL_ELPA_KERNEL_GENERIC
#else
  integer, parameter :: DEFAULT_REAL_ELPA_KERNEL = REAL_ELPA_KERNEL_GENERIC
#endif
  character(35), parameter, dimension(number_of_real_kernels) :: &
  REAL_ELPA_KERNEL_NAMES =    (/"REAL_ELPA_KERNEL_GENERIC         ", &
                                "REAL_ELPA_KERNEL_GENERIC_SIMPLE  ", &
                                "REAL_ELPA_KERNEL_BGP             ", &
                                "REAL_ELPA_KERNEL_BGQ             ", &
                                "REAL_ELPA_KERNEL_SSE             ", &
128
129
130
                                "REAL_ELPA_KERNEL_SSE_BLOCK2      ", &
                                "REAL_ELPA_KERNEL_SSE_BLOCK4      ", &
                                "REAL_ELPA_KERNEL_SSE_BLOCK6      ", &
131
132
                                "REAL_ELPA_KERNEL_AVX_BLOCK2      ", &
                                "REAL_ELPA_KERNEL_AVX_BLOCK4      ", &
133
134
135
136
                                "REAL_ELPA_KERNEL_AVX_BLOCK6      ", &
                                "REAL_ELPA_KERNEL_AVX2_BLOCK2     ", &
                                "REAL_ELPA_KERNEL_AVX2_BLOCK4     ", &
                                "REAL_ELPA_KERNEL_AVX2_BLOCK6     "/)
137

Andreas Marek's avatar
Andreas Marek committed
138
139
140
141
142
143
  integer, parameter :: number_of_complex_kernels           = ELPA2_NUMBER_OF_COMPLEX_KERNELS
  integer, parameter :: COMPLEX_ELPA_KERNEL_GENERIC         = ELPA2_COMPLEX_KERNEL_GENERIC
  integer, parameter :: COMPLEX_ELPA_KERNEL_GENERIC_SIMPLE  = ELPA2_COMPLEX_KERNEL_GENERIC_SIMPLE
  integer, parameter :: COMPLEX_ELPA_KERNEL_BGP             = ELPA2_COMPLEX_KERNEL_BGP
  integer, parameter :: COMPLEX_ELPA_KERNEL_BGQ             = ELPA2_COMPLEX_KERNEL_BGQ
  integer, parameter :: COMPLEX_ELPA_KERNEL_SSE             = ELPA2_COMPLEX_KERNEL_SSE
144
145
  integer, parameter :: COMPLEX_ELPA_KERNEL_SSE_BLOCK1      = ELPA2_COMPLEX_KERNEL_SSE_BLOCK1
  integer, parameter :: COMPLEX_ELPA_KERNEL_SSE_BLOCK2      = ELPA2_COMPLEX_KERNEL_SSE_BLOCK2
Andreas Marek's avatar
Andreas Marek committed
146
147
  integer, parameter :: COMPLEX_ELPA_KERNEL_AVX_BLOCK1      = ELPA2_COMPLEX_KERNEL_AVX_BLOCK1
  integer, parameter :: COMPLEX_ELPA_KERNEL_AVX_BLOCK2      = ELPA2_COMPLEX_KERNEL_AVX_BLOCK2
148
149
  integer, parameter :: COMPLEX_ELPA_KERNEL_AVX2_BLOCK1     = ELPA2_COMPLEX_KERNEL_AVX2_BLOCK1
  integer, parameter :: COMPLEX_ELPA_KERNEL_AVX2_BLOCK2     = ELPA2_COMPLEX_KERNEL_AVX2_BLOCK2
150
151
152
153
154
155
156
157
158
159
160
161

#if defined(WITH_COMPLEX_AVX_BLOCK1_KERNEL)
  integer, parameter :: DEFAULT_COMPLEX_ELPA_KERNEL = COMPLEX_ELPA_KERNEL_GENERIC
#else
  integer, parameter :: DEFAULT_COMPLEX_ELPA_KERNEL = COMPLEX_ELPA_KERNEL_GENERIC
#endif
  character(35), parameter, dimension(number_of_complex_kernels) :: &
  COMPLEX_ELPA_KERNEL_NAMES = (/"COMPLEX_ELPA_KERNEL_GENERIC         ", &
                                "COMPLEX_ELPA_KERNEL_GENERIC_SIMPLE  ", &
                                "COMPLEX_ELPA_KERNEL_BGP             ", &
                                "COMPLEX_ELPA_KERNEL_BGQ             ", &
                                "COMPLEX_ELPA_KERNEL_SSE             ", &
162
163
                                "COMPLEX_ELPA_KERNEL_SSE_BLOCK1      ", &
                                "COMPLEX_ELPA_KERNEL_SSE_BLOCK2      ", &
164
                                "COMPLEX_ELPA_KERNEL_AVX_BLOCK1      ", &
165
166
167
                                "COMPLEX_ELPA_KERNEL_AVX_BLOCK2      ", &
                                "COMPLEX_ELPA_KERNEL_AVX2_BLOCK1     ", &
                                "COMPLEX_ELPA_KERNEL_AVX2_BLOCK2     "/)
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191

  integer, parameter                                    ::             &
           AVAILABLE_REAL_ELPA_KERNELS(number_of_real_kernels) =       &
                                      (/                               &
#if WITH_REAL_GENERIC_KERNEL
                                        1                              &
#else
                                        0                              &
#endif
#if WITH_REAL_GENERIC_SIMPLE_KERNEL
                                          ,1                           &
#else
                                          ,0                           &
#endif
#if WITH_REAL_BGP_KERNEL
                                            ,1                         &
#else
                                            ,0                         &
#endif
#if WITH_REAL_BGQ_KERNEL
                                              ,1                       &
#else
                                              ,0                       &
#endif
192
#if WITH_REAL_SSE_ASSEMBLY_KERNEL
193
194
195
196
                                                ,1                     &
#else
                                                ,0                     &
#endif
197
#if WITH_REAL_SSE_BLOCK2_KERNEL
198
199
200
201
                                                  ,1                   &
#else
                                                  ,0                   &
#endif
202
#if WITH_REAL_SSE_BLOCK4_KERNEL
203
204
205
206
                                                    ,1                 &
#else
                                                    ,0                 &
#endif
207
#if WITH_REAL_SSE_BLOCK6_KERNEL
208
209
210
                                                      ,1               &
#else
                                                      ,0               &
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226

#endif
#if WITH_REAL_AVX_BLOCK2_KERNEL
                                                        ,1             &
#else
                                                        ,0             &
#endif
#if WITH_REAL_AVX_BLOCK4_KERNEL
                                                          ,1           &
#else
                                                          ,0           &
#endif
#if WITH_REAL_AVX_BLOCK6_KERNEL
                                                            ,1         &
#else
                                                            ,0         &
227
#endif
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
#if WITH_REAL_AVX2_BLOCK2_KERNEL
                                                              ,1       &
#else
                                                              ,0       &
#endif
#if WITH_REAL_AVX2_BLOCK4_KERNEL
                                                               ,1      &
#else
                                                               ,0      &
#endif
#if WITH_REAL_AVX2_BLOCK6_KERNEL
                                                               ,1      &
#else
                                                               ,0      &
#endif


245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
                                                       /)

  integer, parameter ::                                                   &
           AVAILABLE_COMPLEX_ELPA_KERNELS(number_of_complex_kernels) =    &
                                      (/                                  &
#if WITH_COMPLEX_GENERIC_KERNEL
                                        1                                 &
#else
                                        0                                 &
#endif
#if WITH_COMPLEX_GENERIC_SIMPLE_KERNEL
                                          ,1                              &
#else
                                          ,0                              &
#endif
#if WITH_COMPLEX_BGP_KERNEL
                                            ,1                            &
#else
                                            ,0                            &
#endif
#if WITH_COMPLEX_BGQ_KERNEL
                                              ,1                          &
#else
                                              ,0                          &
#endif
270
#if WITH_COMPLEX_SSE_ASSEMBLY_KERNEL
271
272
273
274
                                                ,1                        &
#else
                                                ,0                        &
#endif
275
#if WITH_COMPLEX_SSE_BLOCK1_KERNEL
276
277
278
279
                                                  ,1                      &
#else
                                                  ,0                      &
#endif
280
#if WITH_COMPLEX_SSE_BLOCK2_KERNEL
281
282
283
284
                                                    ,1                    &
#else
                                                    ,0                    &
#endif
285
286
287
288
289
290
291
292
293
294
295

#if WITH_COMPLEX_AVX_BLOCK1_KERNEL
                                                      ,1                  &
#else
                                                      ,0                  &
#endif
#if WITH_COMPLEX_AVX_BLOCK2_KERNEL
                                                        ,1                &
#else
                                                        ,0                &
#endif
296
297
298
299
300
301
302
303
304
305
306
#if WITH_COMPLEX_AVX2_BLOCK1_KERNEL
                                                         ,1               &
#else
                                                         ,0               &
#endif
#if WITH_COMPLEX_AVX2_BLOCK2_KERNEL
                                                           ,1             &
#else
                                                           ,0             &
#endif

307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
                                                   /)

!******
  contains
    subroutine print_available_real_kernels
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif
      implicit none

      integer :: i

#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("print_available_real_kernels")
#endif

323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
      do i=1, number_of_real_kernels
        if (AVAILABLE_REAL_ELPA_KERNELS(i) .eq. 1) then
          write(*,*) REAL_ELPA_KERNEL_NAMES(i)
        endif
      enddo
      write(*,*) " "
      write(*,*) " At the moment the following kernel would be choosen:"
      write(*,*) get_actual_real_kernel_name()

#ifdef HAVE_DETAILED_TIMINGS
      call timer%stop("print_available_real_kernels")
#endif

    end subroutine print_available_real_kernels

    subroutine query_available_real_kernels
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif
      implicit none

      integer :: i

#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("query_available_real_kernels")
#endif

350
351
352
353
354
355
356
357
358
359
      do i=1, number_of_real_kernels
        if (AVAILABLE_REAL_ELPA_KERNELS(i) .eq. 1) then
          write(error_unit,*) REAL_ELPA_KERNEL_NAMES(i)
        endif
      enddo
      write(error_unit,*) " "
      write(error_unit,*) " At the moment the following kernel would be choosen:"
      write(error_unit,*) get_actual_real_kernel_name()

#ifdef HAVE_DETAILED_TIMINGS
360
      call timer%stop("query_available_real_kernels")
361
362
#endif

363
    end subroutine query_available_real_kernels
364
365
366
367
368
369
370
371
372
373
374
375
376

    subroutine print_available_complex_kernels
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif

      implicit none

      integer :: i
#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("print_available_complex_kernels")
#endif

377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
      do i=1, number_of_complex_kernels
        if (AVAILABLE_COMPLEX_ELPA_KERNELS(i) .eq. 1) then
           write(*,*) COMPLEX_ELPA_KERNEL_NAMES(i)
        endif
      enddo
      write(*,*) " "
      write(*,*) " At the moment the following kernel would be choosen:"
      write(*,*) get_actual_complex_kernel_name()

#ifdef HAVE_DETAILED_TIMINGS
      call timer%stop("print_available_complex_kernels")
#endif

    end subroutine print_available_complex_kernels

    subroutine query_available_complex_kernels
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif

      implicit none

      integer :: i
#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("query_available_complex_kernels")
#endif

404
405
406
407
408
409
410
411
412
413
      do i=1, number_of_complex_kernels
        if (AVAILABLE_COMPLEX_ELPA_KERNELS(i) .eq. 1) then
           write(error_unit,*) COMPLEX_ELPA_KERNEL_NAMES(i)
        endif
      enddo
      write(error_unit,*) " "
      write(error_unit,*) " At the moment the following kernel would be choosen:"
      write(error_unit,*) get_actual_complex_kernel_name()

#ifdef HAVE_DETAILED_TIMINGS
414
      call timer%stop("query_available_complex_kernels")
415
416
#endif

417
    end subroutine query_available_complex_kernels
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660

    function get_actual_real_kernel() result(actual_kernel)
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif
      implicit none

      integer :: actual_kernel

#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("get_actual_real_kernel")
#endif


      ! if kernel is not choosen via api
      ! check whether set by environment variable
      actual_kernel = real_kernel_via_environment_variable()

      if (actual_kernel .eq. 0) then
        ! if not then set default kernel
        actual_kernel = DEFAULT_REAL_ELPA_KERNEL
      endif

#ifdef HAVE_DETAILED_TIMINGS
      call timer%stop("get_actual_real_kernel")
#endif

    end function get_actual_real_kernel

    function get_actual_real_kernel_name() result(actual_kernel_name)
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif
      implicit none

      character(35) :: actual_kernel_name
      integer       :: actual_kernel

#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("get_actual_real_kernel_name")
#endif

      actual_kernel = get_actual_real_kernel()
      actual_kernel_name = REAL_ELPA_KERNEL_NAMES(actual_kernel)

#ifdef HAVE_DETAILED_TIMINGS
      call timer%stop("get_actual_real_kernel_name")
#endif

    end function get_actual_real_kernel_name

    function get_actual_complex_kernel() result(actual_kernel)
#ifdef HAVE_DETAILED_TIMINGS
      use timings
#endif
      implicit none
      integer :: actual_kernel

#ifdef HAVE_DETAILED_TIMINGS
      call timer%start("get_actual_complex_kernel")
#endif


     ! if kernel is not choosen via api
     ! check whether set by environment variable
     actual_kernel = complex_kernel_via_environment_variable()

     if (actual_kernel .eq. 0) then
       ! if not then set default kernel
       actual_kernel = DEFAULT_COMPLEX_ELPA_KERNEL
     endif

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("get_actual_complex_kernel")
#endif

   end function get_actual_complex_kernel

   function get_actual_complex_kernel_name() result(actual_kernel_name)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     character(35) :: actual_kernel_name
     integer       :: actual_kernel

#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("get_actual_complex_kernel_name")
#endif

     actual_kernel = get_actual_complex_kernel()
     actual_kernel_name = COMPLEX_ELPA_KERNEL_NAMES(actual_kernel)

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("get_actual_complex_kernel_name")
#endif

   end function get_actual_complex_kernel_name

   function check_allowed_real_kernels(THIS_REAL_ELPA_KERNEL) result(err)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     integer, intent(in) :: THIS_REAL_ELPA_KERNEL

     logical             :: err

#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("check_allowed_real_kernels")
#endif
     err = .false.

     if (AVAILABLE_REAL_ELPA_KERNELS(THIS_REAL_ELPA_KERNEL) .ne. 1) err=.true.

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("check_allowed_real_kernels")
#endif

   end function check_allowed_real_kernels

   function check_allowed_complex_kernels(THIS_COMPLEX_ELPA_KERNEL) result(err)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     integer, intent(in) :: THIS_COMPLEX_ELPA_KERNEL

     logical             :: err
#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("check_allowed_complex_kernels")
#endif
     err = .false.

     if (AVAILABLE_COMPLEX_ELPA_KERNELS(THIS_COMPLEX_ELPA_KERNEL) .ne. 1) err=.true.

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("check_allowed_complex_kernels")
#endif

   end function check_allowed_complex_kernels

   function qr_decomposition_via_environment_variable(useQR) result(isSet)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     logical, intent(out) :: useQR
     logical              :: isSet
     CHARACTER(len=255)   :: ELPA_QR_DECOMPOSITION

#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("qr_decomposition_via_environment_variable")
#endif

     isSet = .false.

#if defined(HAVE_ENVIRONMENT_CHECKING)
     call get_environment_variable("ELPA_QR_DECOMPOSITION",ELPA_QR_DECOMPOSITION)
#endif
     if (trim(ELPA_QR_DECOMPOSITION) .eq. "yes") then
       useQR = .true.
       isSet = .true.
     endif
     if (trim(ELPA_QR_DECOMPOSITION) .eq. "no") then
       useQR = .false.
       isSet = .true.
     endif

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("qr_decomposition_via_environment_variable")
#endif

   end function qr_decomposition_via_environment_variable


   function real_kernel_via_environment_variable() result(kernel)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     integer :: kernel
     CHARACTER(len=255) :: REAL_KERNEL_ENVIRONMENT
     integer :: i

#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("real_kernel_via_environment_variable")
#endif

#if defined(HAVE_ENVIRONMENT_CHECKING)
     call get_environment_variable("REAL_ELPA_KERNEL",REAL_KERNEL_ENVIRONMENT)
#endif
     do i=1,size(REAL_ELPA_KERNEL_NAMES(:))
       !     if (trim(dummy_char) .eq. trim(REAL_ELPA_KERNEL_NAMES(i))) then
       if (trim(REAL_KERNEL_ENVIRONMENT) .eq. trim(REAL_ELPA_KERNEL_NAMES(i))) then
         kernel = i
         exit
       else
         kernel = 0
       endif
     enddo

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("real_kernel_via_environment_variable")
#endif

   end function real_kernel_via_environment_variable

   function complex_kernel_via_environment_variable() result(kernel)
#ifdef HAVE_DETAILED_TIMINGS
     use timings
#endif
     implicit none
     integer :: kernel

     CHARACTER(len=255) :: COMPLEX_KERNEL_ENVIRONMENT
     integer :: i

#ifdef HAVE_DETAILED_TIMINGS
     call timer%start("complex_kernel_via_environment_variable")
#endif

#if defined(HAVE_ENVIRONMENT_CHECKING)
     call get_environment_variable("COMPLEX_ELPA_KERNEL",COMPLEX_KERNEL_ENVIRONMENT)
#endif

     do i=1,size(COMPLEX_ELPA_KERNEL_NAMES(:))
       if (trim(COMPLEX_ELPA_KERNEL_NAMES(i)) .eq. trim(COMPLEX_KERNEL_ENVIRONMENT)) then
         kernel = i
         exit
       else
         kernel = 0
       endif
     enddo

#ifdef HAVE_DETAILED_TIMINGS
     call timer%stop("complex_kernel_via_environment_variable")
#endif

   end function
!-------------------------------------------------------------------------------

end module ELPA2_utilities