SCALAPACK 2.2.2
LAPACK: Linear Algebra PACKage
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◆ pilaenvx()

integer function pilaenvx ( integer  ictxt,
integer  ispec,
character*( * )  name,
character*( * )  opts,
integer  n1,
integer  n2,
integer  n3,
integer  n4 
)

Definition at line 1 of file pilaenvx.f.

3*
4* Contribution from the Department of Computing Science and HPC2N,
5* Umea University, Sweden
6*
7* -- ScaLAPACK auxiliary routine (version 2.0.1) --
8* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
9* Univ. of Colorado Denver and University of California, Berkeley.
10* January, 2012
11*
12 IMPLICIT NONE
13*
14* .. Scalar Arguments ..
15 CHARACTER*( * ) NAME, OPTS
16 INTEGER ICTXT, ISPEC, N1, N2, N3, N4
17* ..
18*
19* Purpose
20* =======
21*
22* PILAENVX is called from the ScaLAPACK routines to choose problem-
23* dependent parameters for the local environment. See ISPEC for a
24* description of the parameters.
25*
26* This version provides a set of parameters which should give good,
27* but not optimal, performance on many of the currently available
28* computers. Users are encouraged to modify this subroutine to set
29* the tuning parameters for their particular machine using the option
30* and problem size information in the arguments.
31*
32* This routine will not function correctly if it is converted to all
33* lower case. Converting it to all upper case is allowed.
34*
35* Arguments
36* =========
37*
38* ICTXT (local input) INTEGER
39* On entry, ICTXT specifies the BLACS context handle, indica-
40* ting the global context of the operation. The context itself
41* is global, but the value of ICTXT is local.
42*
43* ISPEC (global input) INTEGER
44* Specifies the parameter to be returned as the value of
45* PILAENVX.
46* = 1: the optimal blocksize; if this value is 1, an unblocked
47* algorithm will give the best performance (unlikely).
48* = 2: the minimum block size for which the block routine
49* should be used; if the usable block size is less than
50* this value, an unblocked routine should be used.
51* = 3: the crossover point (in a block routine, for N less
52* than this value, an unblocked routine should be used)
53* = 4: the number of shifts, used in the nonsymmetric
54* eigenvalue routines (DEPRECATED)
55* = 5: the minimum column dimension for blocking to be used;
56* rectangular blocks must have dimension at least k by m,
57* where k is given by PILAENVX(2,...) and m by PILAENVX(5,...)
58* = 6: the crossover point for the SVD (when reducing an m by n
59* matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds
60* this value, a QR factorization is used first to reduce
61* the matrix to a triangular form.)
62* = 7: the number of processors
63* = 8: the crossover point for the multishift QR method
64* for nonsymmetric eigenvalue problems (DEPRECATED)
65* = 9: maximum size of the subproblems at the bottom of the
66* computation tree in the divide-and-conquer algorithm
67* (used by xGELSD and xGESDD)
68* =10: ieee NaN arithmetic can be trusted not to trap
69* =11: infinity arithmetic can be trusted not to trap
70* 12 <= ISPEC <= 16:
71* PxHSEQR or one of its subroutines,
72* see PIPARMQ for detailed explanation
73* 17 <= ISPEC <= 22:
74* Parameters for PBxTRORD/PxHSEQR (not all), as follows:
75* =17: maximum number of concurrent computational windows;
76* =18: number of eigenvalues/bulges in each window;
77* =19: computational window size;
78* =20: minimal percentage of flops required for
79* performing matrix-matrix multiplications instead
80* of pipelined orthogonal transformations;
81* =21: width of block column slabs for row-wise
82* application of pipelined orthogonal
83* transformations in their factorized form;
84* =22: the maximum number of eigenvalues moved together
85* over a process border;
86* =23: the number of processors involved in AED;
87* =99: Maximum iteration chunksize in OpenMP parallelization
88*
89* NAME (global input) CHARACTER*(*)
90* The name of the calling subroutine, in either upper case or
91* lower case.
92*
93* OPTS (global input) CHARACTER*(*)
94* The character options to the subroutine NAME, concatenated
95* into a single character string. For example, UPLO = 'U',
96* TRANS = 'T', and DIAG = 'N' for a triangular routine would
97* be specified as OPTS = 'UTN'.
98*
99* N1 (global input) INTEGER
100* N2 (global input) INTEGER
101* N3 (global input) INTEGER
102* N4 (global input) INTEGER
103* Problem dimensions for the subroutine NAME; these may not all
104* be required.
105*
106* (PILAENVX) (global output) INTEGER
107* >= 0: the value of the parameter specified by ISPEC
108* < 0: if PILAENVX = -k, the k-th argument had an illegal value.
109*
110* Further Details
111* ===============
112*
113* The following conventions have been used when calling ILAENV from the
114* LAPACK routines:
115* 1) OPTS is a concatenation of all of the character options to
116* subroutine NAME, in the same order that they appear in the
117* argument list for NAME, even if they are not used in determining
118* the value of the parameter specified by ISPEC.
119* 2) The problem dimensions N1, N2, N3, N4 are specified in the order
120* that they appear in the argument list for NAME. N1 is used
121* first, N2 second, and so on, and unused problem dimensions are
122* passed a value of -1.
123* 3) The parameter value returned by ILAENV is checked for validity in
124* the calling subroutine. For example, ILAENV is used to retrieve
125* the optimal blocksize for STRTRI as follows:
126*
127* NB = ILAENV( 1, 'STRTRI', UPLO // DIAG, N, -1, -1, -1 )
128* IF( NB.LE.1 ) NB = MAX( 1, N )
129*
130* The same conventions will hold for this ScaLAPACK-style variant.
131*
132* =====================================================================
133*
134* .. Local Scalars ..
135 INTEGER I, IC, IZ, NB, NBMIN, NX, NPROW, NPCOL, MYROW,
136 $ MYCOL
137 LOGICAL CNAME, SNAME
138 CHARACTER C1*1, C2*2, C4*2, C3*3, SUBNAM*6
139* ..
140* .. Intrinsic Functions ..
141 INTRINSIC char, ichar, int, min, real
142* ..
143* .. External Functions ..
144 INTEGER IEEECK, PIPARMQ, ICEIL
145 EXTERNAL ieeeck, piparmq, iceil
146* ..
147* .. Executable Statements ..
148*
149 IF( ispec.GT.23 ) GO TO 990
150 GO TO ( 10, 10, 10, 80, 90, 100, 110, 120,
151 $ 130, 140, 150, 160, 160, 160, 160, 160,
152 $ 170, 180, 190, 200, 210, 220, 230, 160)ispec
153*
154* Invalid value for ISPEC
155*
156 pilaenvx = -1
157 RETURN
158*
159 10 CONTINUE
160*
161* Convert NAME to upper case if the first character is lower case.
162*
163 pilaenvx = 1
164 subnam = name
165 ic = ichar( subnam( 1: 1 ) )
166 iz = ichar( 'Z' )
167 IF( iz.EQ.90 .OR. iz.EQ.122 ) THEN
168*
169* ASCII character set
170*
171 IF( ic.GE.97 .AND. ic.LE.122 ) THEN
172 subnam( 1: 1 ) = char( ic-32 )
173 DO 20 i = 2, 6
174 ic = ichar( subnam( i: i ) )
175 IF( ic.GE.97 .AND. ic.LE.122 )
176 $ subnam( i: i ) = char( ic-32 )
177 20 CONTINUE
178 END IF
179*
180 ELSE IF( iz.EQ.233 .OR. iz.EQ.169 ) THEN
181*
182* EBCDIC character set
183*
184 IF( ( ic.GE.129 .AND. ic.LE.137 ) .OR.
185 $ ( ic.GE.145 .AND. ic.LE.153 ) .OR.
186 $ ( ic.GE.162 .AND. ic.LE.169 ) ) THEN
187 subnam( 1: 1 ) = char( ic+64 )
188 DO 30 i = 2, 6
189 ic = ichar( subnam( i: i ) )
190 IF( ( ic.GE.129 .AND. ic.LE.137 ) .OR.
191 $ ( ic.GE.145 .AND. ic.LE.153 ) .OR.
192 $ ( ic.GE.162 .AND. ic.LE.169 ) )subnam( i:
193 $ i ) = char( ic+64 )
194 30 CONTINUE
195 END IF
196*
197 ELSE IF( iz.EQ.218 .OR. iz.EQ.250 ) THEN
198*
199* Prime machines: ASCII+128
200*
201 IF( ic.GE.225 .AND. ic.LE.250 ) THEN
202 subnam( 1: 1 ) = char( ic-32 )
203 DO 40 i = 2, 6
204 ic = ichar( subnam( i: i ) )
205 IF( ic.GE.225 .AND. ic.LE.250 )
206 $ subnam( i: i ) = char( ic-32 )
207 40 CONTINUE
208 END IF
209 END IF
210*
211 c1 = subnam( 1: 1 )
212 sname = c1.EQ.'S' .OR. c1.EQ.'D'
213 cname = c1.EQ.'C' .OR. c1.EQ.'Z'
214 IF( .NOT.( cname .OR. sname ) )
215 $ RETURN
216 c2 = subnam( 2: 3 )
217 c3 = subnam( 4: 6 )
218 c4 = c3( 2: 3 )
219*
220 GO TO ( 50, 60, 70 )ispec
221*
222 50 CONTINUE
223*
224* ISPEC = 1: block size
225*
226* In these examples, separate code is provided for setting NB for
227* real and complex. We assume that NB will take the same value in
228* single or double precision.
229*
230 nb = 1
231*
232 IF( c2.EQ.'GE' ) THEN
233 IF( c3.EQ.'TRF' ) THEN
234 IF( sname ) THEN
235 nb = 64
236 ELSE
237 nb = 64
238 END IF
239 ELSE IF( c3.EQ.'QRF' .OR. c3.EQ.'RQF' .OR. c3.EQ.'LQF' .OR.
240 $ c3.EQ.'QLF' ) THEN
241 IF( sname ) THEN
242 nb = 32
243 ELSE
244 nb = 32
245 END IF
246 ELSE IF( c3.EQ.'HRD' ) THEN
247 IF( sname ) THEN
248 nb = 32
249 ELSE
250 nb = 32
251 END IF
252 ELSE IF( c3.EQ.'BRD' ) THEN
253 IF( sname ) THEN
254 nb = 32
255 ELSE
256 nb = 32
257 END IF
258 ELSE IF( c3.EQ.'TRI' ) THEN
259 IF( sname ) THEN
260 nb = 64
261 ELSE
262 nb = 64
263 END IF
264 END IF
265 ELSE IF( c2.EQ.'PO' ) THEN
266 IF( c3.EQ.'TRF' ) THEN
267 IF( sname ) THEN
268 nb = 64
269 ELSE
270 nb = 64
271 END IF
272 END IF
273 ELSE IF( c2.EQ.'SY' ) THEN
274 IF( c3.EQ.'TRF' ) THEN
275 IF( sname ) THEN
276 nb = 64
277 ELSE
278 nb = 64
279 END IF
280 ELSE IF( sname .AND. c3.EQ.'TRD' ) THEN
281 nb = 32
282 ELSE IF( sname .AND. c3.EQ.'GST' ) THEN
283 nb = 64
284 END IF
285 ELSE IF( cname .AND. c2.EQ.'HE' ) THEN
286 IF( c3.EQ.'TRF' ) THEN
287 nb = 64
288 ELSE IF( c3.EQ.'TRD' ) THEN
289 nb = 32
290 ELSE IF( c3.EQ.'GST' ) THEN
291 nb = 64
292 END IF
293 ELSE IF( sname .AND. c2.EQ.'OR' ) THEN
294 IF( c3( 1: 1 ).EQ.'G' ) THEN
295 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
296 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
297 $ THEN
298 nb = 32
299 END IF
300 ELSE IF( c3( 1: 1 ).EQ.'M' ) THEN
301 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
302 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
303 $ THEN
304 nb = 32
305 END IF
306 END IF
307 ELSE IF( cname .AND. c2.EQ.'UN' ) THEN
308 IF( c3( 1: 1 ).EQ.'G' ) THEN
309 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
310 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
311 $ THEN
312 nb = 32
313 END IF
314 ELSE IF( c3( 1: 1 ).EQ.'M' ) THEN
315 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
316 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
317 $ THEN
318 nb = 32
319 END IF
320 END IF
321 ELSE IF( c2.EQ.'GB' ) THEN
322 IF( c3.EQ.'TRF' ) THEN
323 IF( sname ) THEN
324 IF( n4.LE.64 ) THEN
325 nb = 1
326 ELSE
327 nb = 32
328 END IF
329 ELSE
330 IF( n4.LE.64 ) THEN
331 nb = 1
332 ELSE
333 nb = 32
334 END IF
335 END IF
336 END IF
337 ELSE IF( c2.EQ.'PB' ) THEN
338 IF( c3.EQ.'TRF' ) THEN
339 IF( sname ) THEN
340 IF( n2.LE.64 ) THEN
341 nb = 1
342 ELSE
343 nb = 32
344 END IF
345 ELSE
346 IF( n2.LE.64 ) THEN
347 nb = 1
348 ELSE
349 nb = 32
350 END IF
351 END IF
352 END IF
353 ELSE IF( c2.EQ.'TR' ) THEN
354 IF( c3.EQ.'TRI' ) THEN
355 IF( sname ) THEN
356 nb = 64
357 ELSE
358 nb = 64
359 END IF
360 END IF
361 ELSE IF( c2.EQ.'LA' ) THEN
362 IF( c3.EQ.'UUM' ) THEN
363 IF( sname ) THEN
364 nb = 64
365 ELSE
366 nb = 64
367 END IF
368 END IF
369 ELSE IF( sname .AND. c2.EQ.'ST' ) THEN
370 IF( c3.EQ.'EBZ' ) THEN
371 nb = 1
372 END IF
373 END IF
374 pilaenvx = nb
375 RETURN
376*
377 60 CONTINUE
378*
379* ISPEC = 2: minimum block size
380*
381 nbmin = 2
382 IF( c2.EQ.'GE' ) THEN
383 IF( c3.EQ.'QRF' .OR. c3.EQ.'RQF' .OR. c3.EQ.'LQF' .OR. c3.EQ.
384 $ 'QLF' ) THEN
385 IF( sname ) THEN
386 nbmin = 2
387 ELSE
388 nbmin = 2
389 END IF
390 ELSE IF( c3.EQ.'HRD' ) THEN
391 IF( sname ) THEN
392 nbmin = 2
393 ELSE
394 nbmin = 2
395 END IF
396 ELSE IF( c3.EQ.'BRD' ) THEN
397 IF( sname ) THEN
398 nbmin = 2
399 ELSE
400 nbmin = 2
401 END IF
402 ELSE IF( c3.EQ.'TRI' ) THEN
403 IF( sname ) THEN
404 nbmin = 2
405 ELSE
406 nbmin = 2
407 END IF
408 END IF
409 ELSE IF( c2.EQ.'SY' ) THEN
410 IF( c3.EQ.'TRF' ) THEN
411 IF( sname ) THEN
412 nbmin = 8
413 ELSE
414 nbmin = 8
415 END IF
416 ELSE IF( sname .AND. c3.EQ.'TRD' ) THEN
417 nbmin = 2
418 END IF
419 ELSE IF( cname .AND. c2.EQ.'HE' ) THEN
420 IF( c3.EQ.'TRD' ) THEN
421 nbmin = 2
422 END IF
423 ELSE IF( sname .AND. c2.EQ.'OR' ) THEN
424 IF( c3( 1: 1 ).EQ.'G' ) THEN
425 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
426 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
427 $ THEN
428 nbmin = 2
429 END IF
430 ELSE IF( c3( 1: 1 ).EQ.'M' ) THEN
431 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
432 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
433 $ THEN
434 nbmin = 2
435 END IF
436 END IF
437 ELSE IF( cname .AND. c2.EQ.'UN' ) THEN
438 IF( c3( 1: 1 ).EQ.'G' ) THEN
439 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
440 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
441 $ THEN
442 nbmin = 2
443 END IF
444 ELSE IF( c3( 1: 1 ).EQ.'M' ) THEN
445 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
446 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
447 $ THEN
448 nbmin = 2
449 END IF
450 END IF
451 END IF
452 pilaenvx = nbmin
453 RETURN
454*
455 70 CONTINUE
456*
457* ISPEC = 3: crossover point
458*
459 nx = 0
460 IF( c2.EQ.'GE' ) THEN
461 IF( c3.EQ.'QRF' .OR. c3.EQ.'RQF' .OR. c3.EQ.'LQF' .OR. c3.EQ.
462 $ 'QLF' ) THEN
463 IF( sname ) THEN
464 nx = 128
465 ELSE
466 nx = 128
467 END IF
468 ELSE IF( c3.EQ.'HRD' ) THEN
469 IF( sname ) THEN
470 nx = 128
471 ELSE
472 nx = 128
473 END IF
474 ELSE IF( c3.EQ.'BRD' ) THEN
475 IF( sname ) THEN
476 nx = 128
477 ELSE
478 nx = 128
479 END IF
480 END IF
481 ELSE IF( c2.EQ.'SY' ) THEN
482 IF( sname .AND. c3.EQ.'TRD' ) THEN
483 nx = 32
484 END IF
485 ELSE IF( cname .AND. c2.EQ.'HE' ) THEN
486 IF( c3.EQ.'TRD' ) THEN
487 nx = 32
488 END IF
489 ELSE IF( sname .AND. c2.EQ.'OR' ) THEN
490 IF( c3( 1: 1 ).EQ.'G' ) THEN
491 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
492 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
493 $ THEN
494 nx = 128
495 END IF
496 END IF
497 ELSE IF( cname .AND. c2.EQ.'UN' ) THEN
498 IF( c3( 1: 1 ).EQ.'G' ) THEN
499 IF( c4.EQ.'QR' .OR. c4.EQ.'RQ' .OR. c4.EQ.'LQ' .OR. c4.EQ.
500 $ 'QL' .OR. c4.EQ.'HR' .OR. c4.EQ.'TR' .OR. c4.EQ.'BR' )
501 $ THEN
502 nx = 128
503 END IF
504 END IF
505 END IF
506 pilaenvx = nx
507 RETURN
508*
509 80 CONTINUE
510*
511* ISPEC = 4: number of shifts (used by xHSEQR)
512*
513 pilaenvx = 6
514 RETURN
515*
516 90 CONTINUE
517*
518* ISPEC = 5: minimum column dimension (not used)
519*
520 pilaenvx = 2
521 RETURN
522*
523 100 CONTINUE
524*
525* ISPEC = 6: crossover point for SVD (used by xGELSS and xGESVD)
526*
527 pilaenvx = int( real( min( n1, n2 ) )*1.6e0 )
528 RETURN
529*
530 110 CONTINUE
531*
532* ISPEC = 7: number of processors (not used)
533*
534 pilaenvx = 1
535 RETURN
536*
537 120 CONTINUE
538*
539* ISPEC = 8: crossover point for multishift (used by xHSEQR)
540*
541 pilaenvx = 50
542 RETURN
543*
544 130 CONTINUE
545*
546* ISPEC = 9: maximum size of the subproblems at the bottom of the
547* computation tree in the divide-and-conquer algorithm
548* (used by xGELSD and xGESDD)
549*
550 pilaenvx = 25
551 RETURN
552*
553 140 CONTINUE
554*
555* ISPEC = 10: ieee NaN arithmetic can be trusted not to trap
556*
557* PILAENVX = 0
558 pilaenvx = 1
559 IF( pilaenvx.EQ.1 ) THEN
560 pilaenvx = ieeeck( 0, 0.0, 1.0 )
561 END IF
562 RETURN
563*
564 150 CONTINUE
565*
566* ISPEC = 11: infinity arithmetic can be trusted not to trap
567*
568* PILAENVX = 0
569 pilaenvx = 1
570 IF( pilaenvx.EQ.1 ) THEN
571 pilaenvx = ieeeck( 1, 0.0, 1.0 )
572 END IF
573 RETURN
574*
575 160 CONTINUE
576*
577* 12 <= ISPEC <= 16 or ISPEC = 24: xHSEQR or one of its subroutines.
578*
579 pilaenvx = piparmq( ictxt, ispec, name, opts, n1, n2, n3, n4 )
580 RETURN
581*
582 170 CONTINUE
583*
584* ISPEC = 17: maximum number of independent computational windows
585*
586 CALL blacs_gridinfo( ictxt, nprow, npcol, myrow, mycol )
587 pilaenvx = min( iceil(n1,n2), min( nprow, npcol) )
588 RETURN
589*
590 180 CONTINUE
591*
592* ISPEC = 18: number of eigenvalues in each window
593*
594 pilaenvx = min(n2/2,40)
595 RETURN
596*
597 190 CONTINUE
598*
599* ISPEC = 19: computational window size
600*
601 pilaenvx = min(n2,80)
602 RETURN
603*
604 200 CONTINUE
605*
606* ISPEC = 20: minimal percentage of flops required for
607* performing matrix-matrix multiplications instead of
608* pipelined orthogonal transformations
609*
610*
611 pilaenvx = 50
612 RETURN
613*
614 210 CONTINUE
615*
616* ISPEC = 21: width of block column slabs for row-wise
617* application of pipelined orthogonal transformations in
618* their factorized form
619*
620*
621 pilaenvx = min(n2,32)
622 RETURN
623*
624 220 CONTINUE
625*
626* ISPEC = 22: maximum number of eigenvalues to bring over
627* the block border
628*
629*
630 pilaenvx = min(n2/2,40)
631 RETURN
632 230 CONTINUE
633*
634* ISPEC = 23: number of processors involved in AED
635*
636*
637 pilaenvx = iceil(n1, iceil(384, n2)*n2)
638 RETURN
639 990 CONTINUE
640*
641* ISPEC = 99: maximum chunksize of iterations in OpenMP
642* parallelization
643*
644 pilaenvx = 32
645 RETURN
646*
647* End of PILAENVX
648*
iceil
integer function iceil(inum, idenom)
Definition iceil.f:2
min
#define min(A, B)
Definition pcgemr.c:181
pilaenvx
integer function pilaenvx(ictxt, ispec, name, opts, n1, n2, n3, n4)
Definition pilaenvx.f:3
piparmq
integer function piparmq(ictxt, ispec, name, opts, n, ilo, ihi, lworknb)
Definition piparmq.f:3
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