| blob | d69bb30361a14701f15488077eab72a7bc5217b7 |
1 INTEGER FUNCTION ILAENV( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
2 !
3 ! -- LAPACK auxiliary routine (version 3.1.1) --
4 ! Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
5 ! January 2007
6 !
7 ! .. Scalar Arguments ..
8 CHARACTER*( * ) NAME, OPTS
9 INTEGER ISPEC, N1, N2, N3, N4
10 ! ..
11 !
12 ! Purpose
13 ! =======
14 !
15 ! ILAENV is called from the LAPACK routines to choose problem-dependent
16 ! parameters for the local environment. See ISPEC for a description of
17 ! the parameters.
18 !
19 ! ILAENV returns an INTEGER
20 ! if ILAENV >= 0: ILAENV returns the value of the parameter specified by ISPEC
21 ! if ILAENV < 0: if ILAENV = -k, the k-th argument had an illegal value.
22 !
23 ! This version provides a set of parameters which should give good,
24 ! but not optimal, performance on many of the currently available
25 ! computers. Users are encouraged to modify this subroutine to set
26 ! the tuning parameters for their particular machine using the option
27 ! and problem size information in the arguments.
28 !
29 ! This routine will not function correctly if it is converted to all
30 ! lower case. Converting it to all upper case is allowed.
31 !
32 ! Arguments
33 ! =========
34 !
35 ! ISPEC (input) INTEGER
36 ! Specifies the parameter to be returned as the value of
37 ! ILAENV.
38 ! = 1: the optimal blocksize; if this value is 1, an unblocked
39 ! algorithm will give the best performance.
40 ! = 2: the minimum block size for which the block routine
41 ! should be used; if the usable block size is less than
42 ! this value, an unblocked routine should be used.
43 ! = 3: the crossover point (in a block routine, for N less
44 ! than this value, an unblocked routine should be used)
45 ! = 4: the number of shifts, used in the nonsymmetric
46 ! eigenvalue routines (DEPRECATED)
47 ! = 5: the minimum column dimension for blocking to be used;
48 ! rectangular blocks must have dimension at least k by m,
49 ! where k is given by ILAENV(2,...) and m by ILAENV(5,...)
50 ! = 6: the crossover point for the SVD (when reducing an m by n
51 ! matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds
52 ! this value, a QR factorization is used first to reduce
53 ! the matrix to a triangular form.)
54 ! = 7: the number of processors
55 ! = 8: the crossover point for the multishift QR method
56 ! for nonsymmetric eigenvalue problems (DEPRECATED)
57 ! = 9: maximum size of the subproblems at the bottom of the
58 ! computation tree in the divide-and-conquer algorithm
59 ! (used by xGELSD and xGESDD)
60 ! =10: ieee NaN arithmetic can be trusted not to trap
61 ! =11: infinity arithmetic can be trusted not to trap
62 ! 12 <= ISPEC <= 16:
63 ! xHSEQR or one of its subroutines,
64 ! see IPARMQ for detailed explanation
65 !
66 ! NAME (input) CHARACTER*(*)
67 ! The name of the calling subroutine, in either upper case or
68 ! lower case.
69 !
70 ! OPTS (input) CHARACTER*(*)
71 ! The character options to the subroutine NAME, concatenated
72 ! into a single character string. For example, UPLO = 'U',
73 ! TRANS = 'T', and DIAG = 'N' for a triangular routine would
74 ! be specified as OPTS = 'UTN'.
75 !
76 ! N1 (input) INTEGER
77 ! N2 (input) INTEGER
78 ! N3 (input) INTEGER
79 ! N4 (input) INTEGER
80 ! Problem dimensions for the subroutine NAME; these may not all
81 ! be required.
82 !
83 ! Further Details
84 ! ===============
85 !
86 ! The following conventions have been used when calling ILAENV from the
87 ! LAPACK routines:
88 ! 1) OPTS is a concatenation of all of the character options to
89 ! subroutine NAME, in the same order that they appear in the
90 ! argument list for NAME, even if they are not used in determining
91 ! the value of the parameter specified by ISPEC.
92 ! 2) The problem dimensions N1, N2, N3, N4 are specified in the order
93 ! that they appear in the argument list for NAME. N1 is used
94 ! first, N2 second, and so on, and unused problem dimensions are
95 ! passed a value of -1.
96 ! 3) The parameter value returned by ILAENV is checked for validity in
97 ! the calling subroutine. For example, ILAENV is used to retrieve
98 ! the optimal blocksize for STRTRI as follows:
99 !
100 ! NB = ILAENV( 1, 'STRTRI', UPLO // DIAG, N, -1, -1, -1 )
101 ! IF( NB.LE.1 ) NB = MAX( 1, N )
102 !
103 ! =====================================================================
104 !
105 ! .. Local Scalars ..
106 INTEGER I, IC, IZ, NB, NBMIN, NX
107 LOGICAL CNAME, SNAME
108 CHARACTER C1*1, C2*2, C4*2, C3*3, SUBNAM*6
109 ! ..
110 ! .. Intrinsic Functions ..
111 INTRINSIC CHAR, ICHAR, INT, MIN, REAL
112 ! ..
113 ! .. External Functions ..
114 ! INTEGER IEEECK, IPARMQ
115 ! EXTERNAL IEEECK, IPARMQ
116 ! ..
117 ! .. Executable Statements ..
118 !
119 GO TO ( 10, 10, 10, 80, 90, 100, 110, 120, &
120 130, 140, 150, 160, 160, 160, 160, 160 )ISPEC
121 !
122 ! Invalid value for ISPEC
123 !
124 ILAENV = -1
125 RETURN
126 !
127 10 CONTINUE
128 !
129 ! Convert NAME to upper case if the first character is lower case.
130 !
131 ILAENV = 1
132 SUBNAM = NAME
133 IC = ICHAR( SUBNAM( 1: 1 ) )
134 IZ = ICHAR( 'Z' )
135 IF( IZ.EQ.90 .OR. IZ.EQ.122 ) THEN
136 !
137 ! ASCII character set
138 !
139 IF( IC.GE.97 .AND. IC.LE.122 ) THEN
140 SUBNAM( 1: 1 ) = CHAR( IC-32 )
141 DO 20 I = 2, 6
142 IC = ICHAR( SUBNAM( I: I ) )
143 IF( IC.GE.97 .AND. IC.LE.122 ) &
144 SUBNAM( I: I ) = CHAR( IC-32 )
145 20 CONTINUE
146 END IF
147 !
148 ELSE IF( IZ.EQ.233 .OR. IZ.EQ.169 ) THEN
149 !
150 ! EBCDIC character set
151 !
152 IF( ( IC.GE.129 .AND. IC.LE.137 ) .OR. &
153 ( IC.GE.145 .AND. IC.LE.153 ) .OR. &
154 ( IC.GE.162 .AND. IC.LE.169 ) ) THEN
155 SUBNAM( 1: 1 ) = CHAR( IC+64 )
156 DO 30 I = 2, 6
157 IC = ICHAR( SUBNAM( I: I ) )
158 IF( ( IC.GE.129 .AND. IC.LE.137 ) .OR. &
159 ( IC.GE.145 .AND. IC.LE.153 ) .OR. &
160 ( IC.GE.162 .AND. IC.LE.169 ) )SUBNAM( I: &
161 I ) = CHAR( IC+64 )
162 30 CONTINUE
163 END IF
164 !
165 ELSE IF( IZ.EQ.218 .OR. IZ.EQ.250 ) THEN
166 !
167 ! Prime machines: ASCII+128
168 !
169 IF( IC.GE.225 .AND. IC.LE.250 ) THEN
170 SUBNAM( 1: 1 ) = CHAR( IC-32 )
171 DO 40 I = 2, 6
172 IC = ICHAR( SUBNAM( I: I ) )
173 IF( IC.GE.225 .AND. IC.LE.250 ) &
174 SUBNAM( I: I ) = CHAR( IC-32 )
175 40 CONTINUE
176 END IF
177 END IF
178 !
179 C1 = SUBNAM( 1: 1 )
180 SNAME = C1.EQ.'S' .OR. C1.EQ.'D'
181 CNAME = C1.EQ.'C' .OR. C1.EQ.'Z'
182 IF( .NOT.( CNAME .OR. SNAME ) ) &
183 RETURN
184 C2 = SUBNAM( 2: 3 )
185 C3 = SUBNAM( 4: 6 )
186 C4 = C3( 2: 3 )
187 !
188 GO TO ( 50, 60, 70 )ISPEC
189 !
190 50 CONTINUE
191 !
192 ! ISPEC = 1: block size
193 !
194 ! In these examples, separate code is provided for setting NB for
195 ! real and complex. We assume that NB will take the same value in
196 ! single or double precision.
197 !
198 NB = 1
199 !
200 IF( C2.EQ.'GE' ) THEN
201 IF( C3.EQ.'TRF' ) THEN
202 IF( SNAME ) THEN
203 NB = 64
204 ELSE
205 NB = 64
206 END IF
207 ELSE IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. &
208 C3.EQ.'QLF' ) THEN
209 IF( SNAME ) THEN
210 NB = 32
211 ELSE
212 NB = 32
213 END IF
214 ELSE IF( C3.EQ.'HRD' ) THEN
215 IF( SNAME ) THEN
216 NB = 32
217 ELSE
218 NB = 32
219 END IF
220 ELSE IF( C3.EQ.'BRD' ) THEN
221 IF( SNAME ) THEN
222 NB = 32
223 ELSE
224 NB = 32
225 END IF
226 ELSE IF( C3.EQ.'TRI' ) THEN
227 IF( SNAME ) THEN
228 NB = 64
229 ELSE
230 NB = 64
231 END IF
232 END IF
233 ELSE IF( C2.EQ.'PO' ) THEN
234 IF( C3.EQ.'TRF' ) THEN
235 IF( SNAME ) THEN
236 NB = 64
237 ELSE
238 NB = 64
239 END IF
240 END IF
241 ELSE IF( C2.EQ.'SY' ) THEN
242 IF( C3.EQ.'TRF' ) THEN
243 IF( SNAME ) THEN
244 NB = 64
245 ELSE
246 NB = 64
247 END IF
248 ELSE IF( SNAME .AND. C3.EQ.'TRD' ) THEN
249 NB = 32
250 ELSE IF( SNAME .AND. C3.EQ.'GST' ) THEN
251 NB = 64
252 END IF
253 ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
254 IF( C3.EQ.'TRF' ) THEN
255 NB = 64
256 ELSE IF( C3.EQ.'TRD' ) THEN
257 NB = 32
258 ELSE IF( C3.EQ.'GST' ) THEN
259 NB = 64
260 END IF
261 ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
262 IF( C3( 1: 1 ).EQ.'G' ) THEN
263 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
264 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
265 THEN
266 NB = 32
267 END IF
268 ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
269 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
270 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
271 THEN
272 NB = 32
273 END IF
274 END IF
275 ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
276 IF( C3( 1: 1 ).EQ.'G' ) THEN
277 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
278 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
279 THEN
280 NB = 32
281 END IF
282 ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
283 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
284 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
285 THEN
286 NB = 32
287 END IF
288 END IF
289 ELSE IF( C2.EQ.'GB' ) THEN
290 IF( C3.EQ.'TRF' ) THEN
291 IF( SNAME ) THEN
292 IF( N4.LE.64 ) THEN
293 NB = 1
294 ELSE
295 NB = 32
296 END IF
297 ELSE
298 IF( N4.LE.64 ) THEN
299 NB = 1
300 ELSE
301 NB = 32
302 END IF
303 END IF
304 END IF
305 ELSE IF( C2.EQ.'PB' ) THEN
306 IF( C3.EQ.'TRF' ) THEN
307 IF( SNAME ) THEN
308 IF( N2.LE.64 ) THEN
309 NB = 1
310 ELSE
311 NB = 32
312 END IF
313 ELSE
314 IF( N2.LE.64 ) THEN
315 NB = 1
316 ELSE
317 NB = 32
318 END IF
319 END IF
320 END IF
321 ELSE IF( C2.EQ.'TR' ) THEN
322 IF( C3.EQ.'TRI' ) THEN
323 IF( SNAME ) THEN
324 NB = 64
325 ELSE
326 NB = 64
327 END IF
328 END IF
329 ELSE IF( C2.EQ.'LA' ) THEN
330 IF( C3.EQ.'UUM' ) THEN
331 IF( SNAME ) THEN
332 NB = 64
333 ELSE
334 NB = 64
335 END IF
336 END IF
337 ELSE IF( SNAME .AND. C2.EQ.'ST' ) THEN
338 IF( C3.EQ.'EBZ' ) THEN
339 NB = 1
340 END IF
341 END IF
342 ILAENV = NB
343 RETURN
344 !
345 60 CONTINUE
346 !
347 ! ISPEC = 2: minimum block size
348 !
349 NBMIN = 2
350 IF( C2.EQ.'GE' ) THEN
351 IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. C3.EQ. &
352 'QLF' ) THEN
353 IF( SNAME ) THEN
354 NBMIN = 2
355 ELSE
356 NBMIN = 2
357 END IF
358 ELSE IF( C3.EQ.'HRD' ) THEN
359 IF( SNAME ) THEN
360 NBMIN = 2
361 ELSE
362 NBMIN = 2
363 END IF
364 ELSE IF( C3.EQ.'BRD' ) THEN
365 IF( SNAME ) THEN
366 NBMIN = 2
367 ELSE
368 NBMIN = 2
369 END IF
370 ELSE IF( C3.EQ.'TRI' ) THEN
371 IF( SNAME ) THEN
372 NBMIN = 2
373 ELSE
374 NBMIN = 2
375 END IF
376 END IF
377 ELSE IF( C2.EQ.'SY' ) THEN
378 IF( C3.EQ.'TRF' ) THEN
379 IF( SNAME ) THEN
380 NBMIN = 8
381 ELSE
382 NBMIN = 8
383 END IF
384 ELSE IF( SNAME .AND. C3.EQ.'TRD' ) THEN
385 NBMIN = 2
386 END IF
387 ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
388 IF( C3.EQ.'TRD' ) THEN
389 NBMIN = 2
390 END IF
391 ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
392 IF( C3( 1: 1 ).EQ.'G' ) THEN
393 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
394 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
395 THEN
396 NBMIN = 2
397 END IF
398 ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
399 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
400 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
401 THEN
402 NBMIN = 2
403 END IF
404 END IF
405 ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
406 IF( C3( 1: 1 ).EQ.'G' ) THEN
407 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
408 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
409 THEN
410 NBMIN = 2
411 END IF
412 ELSE IF( C3( 1: 1 ).EQ.'M' ) THEN
413 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
414 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
415 THEN
416 NBMIN = 2
417 END IF
418 END IF
419 END IF
420 ILAENV = NBMIN
421 RETURN
422 !
423 70 CONTINUE
424 !
425 ! ISPEC = 3: crossover point
426 !
427 NX = 0
428 IF( C2.EQ.'GE' ) THEN
429 IF( C3.EQ.'QRF' .OR. C3.EQ.'RQF' .OR. C3.EQ.'LQF' .OR. C3.EQ. &
430 'QLF' ) THEN
431 IF( SNAME ) THEN
432 NX = 128
433 ELSE
434 NX = 128
435 END IF
436 ELSE IF( C3.EQ.'HRD' ) THEN
437 IF( SNAME ) THEN
438 NX = 128
439 ELSE
440 NX = 128
441 END IF
442 ELSE IF( C3.EQ.'BRD' ) THEN
443 IF( SNAME ) THEN
444 NX = 128
445 ELSE
446 NX = 128
447 END IF
448 END IF
449 ELSE IF( C2.EQ.'SY' ) THEN
450 IF( SNAME .AND. C3.EQ.'TRD' ) THEN
451 NX = 32
452 END IF
453 ELSE IF( CNAME .AND. C2.EQ.'HE' ) THEN
454 IF( C3.EQ.'TRD' ) THEN
455 NX = 32
456 END IF
457 ELSE IF( SNAME .AND. C2.EQ.'OR' ) THEN
458 IF( C3( 1: 1 ).EQ.'G' ) THEN
459 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
460 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
461 THEN
462 NX = 128
463 END IF
464 END IF
465 ELSE IF( CNAME .AND. C2.EQ.'UN' ) THEN
466 IF( C3( 1: 1 ).EQ.'G' ) THEN
467 IF( C4.EQ.'QR' .OR. C4.EQ.'RQ' .OR. C4.EQ.'LQ' .OR. C4.EQ. &
468 'QL' .OR. C4.EQ.'HR' .OR. C4.EQ.'TR' .OR. C4.EQ.'BR' ) &
469 THEN
470 NX = 128
471 END IF
472 END IF
473 END IF
474 ILAENV = NX
475 RETURN
476 !
477 80 CONTINUE
478 !
479 ! ISPEC = 4: number of shifts (used by xHSEQR)
480 !
481 ILAENV = 6
482 RETURN
483 !
484 90 CONTINUE
485 !
486 ! ISPEC = 5: minimum column dimension (not used)
487 !
488 ILAENV = 2
489 RETURN
490 !
491 100 CONTINUE
492 !
493 ! ISPEC = 6: crossover point for SVD (used by xGELSS and xGESVD)
494 !
495 ILAENV = INT( REAL( MIN( N1, N2 ) )*1.6E0 )
496 RETURN
497 !
498 110 CONTINUE
499 !
500 ! ISPEC = 7: number of processors (not used)
501 !
502 ILAENV = 1
503 RETURN
504 !
505 120 CONTINUE
506 !
507 ! ISPEC = 8: crossover point for multishift (used by xHSEQR)
508 !
509 ILAENV = 50
510 RETURN
511 !
512 130 CONTINUE
513 !
514 ! ISPEC = 9: maximum size of the subproblems at the bottom of the
515 ! computation tree in the divide-and-conquer algorithm
516 ! (used by xGELSD and xGESDD)
517 !
518 ILAENV = 25
519 RETURN
520 !
521 140 CONTINUE
522 !
523 ! ISPEC = 10: ieee NaN arithmetic can be trusted not to trap
524 !
525 ! ILAENV = 0
526 ILAENV = 1
527 IF( ILAENV.EQ.1 ) THEN
528 ILAENV = IEEECK( 0, 0.0, 1.0 )
529 END IF
530 RETURN
531 !
532 150 CONTINUE
533 !
534 ! ISPEC = 11: infinity arithmetic can be trusted not to trap
535 !
536 ! ILAENV = 0
537 ILAENV = 1
538 IF( ILAENV.EQ.1 ) THEN
539 ILAENV = IEEECK( 1, 0.0, 1.0 )
540 END IF
541 RETURN
542 !
543 160 CONTINUE
544 !
545 ! 12 <= ISPEC <= 16: xHSEQR or one of its subroutines.
546 !
547 ILAENV = IPARMQ( ISPEC, NAME, OPTS, N1, N2, N3, N4 )
548 RETURN
549 !
550 ! End of ILAENV
551 !
552 END FUNCTION ILAENV