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zhetrf_aa_2stage.f
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1*> \brief \b ZHETRF_AA_2STAGE
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
9*> Download ZHETRF_AA_2STAGE + dependencies
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zhetrf_aa_2stage.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zhetrf_aa_2stage.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zhetrf_aa_2stage.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18* Definition:
19* ===========
20*
21* SUBROUTINE ZHETRF_AA_2STAGE( UPLO, N, A, LDA, TB, LTB, IPIV,
22* IPIV2, WORK, LWORK, INFO )
23*
24* .. Scalar Arguments ..
25* CHARACTER UPLO
26* INTEGER N, LDA, LTB, LWORK, INFO
27* ..
28* .. Array Arguments ..
29* INTEGER IPIV( * ), IPIV2( * )
30* COMPLEX*16 A( LDA, * ), TB( * ), WORK( * )
31* ..
32*
33*> \par Purpose:
34* =============
35*>
36*> \verbatim
37*>
38*> ZHETRF_AA_2STAGE computes the factorization of a double hermitian matrix A
39*> using the Aasen's algorithm. The form of the factorization is
40*>
41*> A = U**H*T*U or A = L*T*L**H
42*>
43*> where U (or L) is a product of permutation and unit upper (lower)
44*> triangular matrices, and T is a hermitian band matrix with the
45*> bandwidth of NB (NB is internally selected and stored in TB( 1 ), and T is
46*> LU factorized with partial pivoting).
47*>
48*> This is the blocked version of the algorithm, calling Level 3 BLAS.
49*> \endverbatim
50*
51* Arguments:
52* ==========
53*
54*> \param[in] UPLO
55*> \verbatim
56*> UPLO is CHARACTER*1
57*> = 'U': Upper triangle of A is stored;
58*> = 'L': Lower triangle of A is stored.
59*> \endverbatim
60*>
61*> \param[in] N
62*> \verbatim
63*> N is INTEGER
64*> The order of the matrix A. N >= 0.
65*> \endverbatim
66*>
67*> \param[in,out] A
68*> \verbatim
69*> A is COMPLEX*16 array, dimension (LDA,N)
70*> On entry, the hermitian matrix A. If UPLO = 'U', the leading
71*> N-by-N upper triangular part of A contains the upper
72*> triangular part of the matrix A, and the strictly lower
73*> triangular part of A is not referenced. If UPLO = 'L', the
74*> leading N-by-N lower triangular part of A contains the lower
75*> triangular part of the matrix A, and the strictly upper
76*> triangular part of A is not referenced.
77*>
78*> On exit, L is stored below (or above) the subdiaonal blocks,
79*> when UPLO is 'L' (or 'U').
80*> \endverbatim
81*>
82*> \param[in] LDA
83*> \verbatim
84*> LDA is INTEGER
85*> The leading dimension of the array A. LDA >= max(1,N).
86*> \endverbatim
87*>
88*> \param[out] TB
89*> \verbatim
90*> TB is COMPLEX*16 array, dimension (LTB)
91*> On exit, details of the LU factorization of the band matrix.
92*> \endverbatim
93*>
94*> \param[in] LTB
95*> \verbatim
96*> LTB is INTEGER
97*> The size of the array TB. LTB >= 4*N, internally
98*> used to select NB such that LTB >= (3*NB+1)*N.
99*>
100*> If LTB = -1, then a workspace query is assumed; the
101*> routine only calculates the optimal size of LTB,
102*> returns this value as the first entry of TB, and
103*> no error message related to LTB is issued by XERBLA.
104*> \endverbatim
105*>
106*> \param[out] IPIV
107*> \verbatim
108*> IPIV is INTEGER array, dimension (N)
109*> On exit, it contains the details of the interchanges, i.e.,
110*> the row and column k of A were interchanged with the
111*> row and column IPIV(k).
112*> \endverbatim
113*>
114*> \param[out] IPIV2
115*> \verbatim
116*> IPIV2 is INTEGER array, dimension (N)
117*> On exit, it contains the details of the interchanges, i.e.,
118*> the row and column k of T were interchanged with the
119*> row and column IPIV(k).
120*> \endverbatim
121*>
122*> \param[out] WORK
123*> \verbatim
124*> WORK is COMPLEX*16 workspace of size LWORK
125*> \endverbatim
126*>
127*> \param[in] LWORK
128*> \verbatim
129*> LWORK is INTEGER
130*> The size of WORK. LWORK >= N, internally used to select NB
131*> such that LWORK >= N*NB.
132*>
133*> If LWORK = -1, then a workspace query is assumed; the
134*> routine only calculates the optimal size of the WORK array,
135*> returns this value as the first entry of the WORK array, and
136*> no error message related to LWORK is issued by XERBLA.
137*> \endverbatim
138*>
139*> \param[out] INFO
140*> \verbatim
141*> INFO is INTEGER
142*> = 0: successful exit
143*> < 0: if INFO = -i, the i-th argument had an illegal value.
144*> > 0: if INFO = i, band LU factorization failed on i-th column
145*> \endverbatim
146*
147* Authors:
148* ========
149*
150*> \author Univ. of Tennessee
151*> \author Univ. of California Berkeley
152*> \author Univ. of Colorado Denver
153*> \author NAG Ltd.
154*
155*> \ingroup complex16SYcomputational
156*
157* =====================================================================
158 SUBROUTINE zhetrf_aa_2stage( UPLO, N, A, LDA, TB, LTB, IPIV,
159 $ IPIV2, WORK, LWORK, INFO )
160*
161* -- LAPACK computational routine --
162* -- LAPACK is a software package provided by Univ. of Tennessee, --
163* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
164*
165 IMPLICIT NONE
166*
167* .. Scalar Arguments ..
168 CHARACTER UPLO
169 INTEGER N, LDA, LTB, LWORK, INFO
170* ..
171* .. Array Arguments ..
172 INTEGER IPIV( * ), IPIV2( * )
173 COMPLEX*16 A( LDA, * ), TB( * ), WORK( * )
174* ..
175*
176* =====================================================================
177* .. Parameters ..
178 COMPLEX*16 ZERO, ONE
179 parameter( zero = ( 0.0e+0, 0.0e+0 ),
180 $ one = ( 1.0e+0, 0.0e+0 ) )
181*
182* .. Local Scalars ..
183 LOGICAL UPPER, TQUERY, WQUERY
184 INTEGER I, J, K, I1, I2, TD
185 INTEGER LDTB, NB, KB, JB, NT, IINFO
186 COMPLEX*16 PIV
187* ..
188* .. External Functions ..
189 LOGICAL LSAME
190 INTEGER ILAENV
191 EXTERNAL lsame, ilaenv
192* ..
193* .. External Subroutines ..
194 EXTERNAL xerbla, zcopy, zlacgv, zlacpy,
195 $ zlaset, zgbtrf, zgemm, zgetrf,
196 $ zhegst, zswap, ztrsm
197* ..
198* .. Intrinsic Functions ..
199 INTRINSIC dconjg, min, max
200* ..
201* .. Executable Statements ..
202*
203* Test the input parameters.
204*
205 info = 0
206 upper = lsame( uplo, 'U' )
207 wquery = ( lwork.EQ.-1 )
208 tquery = ( ltb.EQ.-1 )
209 IF( .NOT.upper .AND. .NOT.lsame( uplo, 'L' ) ) THEN
210 info = -1
211 ELSE IF( n.LT.0 ) THEN
212 info = -2
213 ELSE IF( lda.LT.max( 1, n ) ) THEN
214 info = -4
215 ELSE IF ( ltb .LT. 4*n .AND. .NOT.tquery ) THEN
216 info = -6
217 ELSE IF ( lwork .LT. n .AND. .NOT.wquery ) THEN
218 info = -10
219 END IF
220*
221 IF( info.NE.0 ) THEN
222 CALL xerbla( 'ZHETRF_AA_2STAGE', -info )
223 RETURN
224 END IF
225*
226* Answer the query
227*
228 nb = ilaenv( 1, 'ZHETRF_AA_2STAGE', uplo, n, -1, -1, -1 )
229 IF( info.EQ.0 ) THEN
230 IF( tquery ) THEN
231 tb( 1 ) = (3*nb+1)*n
232 END IF
233 IF( wquery ) THEN
234 work( 1 ) = n*nb
235 END IF
236 END IF
237 IF( tquery .OR. wquery ) THEN
238 RETURN
239 END IF
240*
241* Quick return
242*
243 IF ( n.EQ.0 ) THEN
244 RETURN
245 ENDIF
246*
247* Determine the number of the block size
248*
249 ldtb = ltb/n
250 IF( ldtb .LT. 3*nb+1 ) THEN
251 nb = (ldtb-1)/3
252 END IF
253 IF( lwork .LT. nb*n ) THEN
254 nb = lwork/n
255 END IF
256*
257* Determine the number of the block columns
258*
259 nt = (n+nb-1)/nb
260 td = 2*nb
261 kb = min(nb, n)
262*
263* Initialize vectors/matrices
264*
265 DO j = 1, kb
266 ipiv( j ) = j
267 END DO
268*
269* Save NB
270*
271 tb( 1 ) = nb
272*
273 IF( upper ) THEN
274*
275* .....................................................
276* Factorize A as U**H*D*U using the upper triangle of A
277* .....................................................
278*
279 DO j = 0, nt-1
280*
281* Generate Jth column of W and H
282*
283 kb = min(nb, n-j*nb)
284 DO i = 1, j-1
285 IF( i.EQ.1 ) THEN
286* H(I,J) = T(I,I)*U(I,J) + T(I+1,I)*U(I+1,J)
287 IF( i .EQ. (j-1) ) THEN
288 jb = nb+kb
289 ELSE
290 jb = 2*nb
291 END IF
292 CALL zgemm( 'NoTranspose', 'NoTranspose',
293 $ nb, kb, jb,
294 $ one, tb( td+1 + (i*nb)*ldtb ), ldtb-1,
295 $ a( (i-1)*nb+1, j*nb+1 ), lda,
296 $ zero, work( i*nb+1 ), n )
297 ELSE
298* H(I,J) = T(I,I-1)*U(I-1,J) + T(I,I)*U(I,J) + T(I,I+1)*U(I+1,J)
299 IF( i .EQ. (j-1) ) THEN
300 jb = 2*nb+kb
301 ELSE
302 jb = 3*nb
303 END IF
304 CALL zgemm( 'NoTranspose', 'NoTranspose',
305 $ nb, kb, jb,
306 $ one, tb( td+nb+1 + ((i-1)*nb)*ldtb ),
307 $ ldtb-1,
308 $ a( (i-2)*nb+1, j*nb+1 ), lda,
309 $ zero, work( i*nb+1 ), n )
310 END IF
311 END DO
312*
313* Compute T(J,J)
314*
315 CALL zlacpy( 'Upper', kb, kb, a( j*nb+1, j*nb+1 ), lda,
316 $ tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
317 IF( j.GT.1 ) THEN
318* T(J,J) = U(1:J,J)'*H(1:J)
319 CALL zgemm( 'Conjugate transpose', 'NoTranspose',
320 $ kb, kb, (j-1)*nb,
321 $ -one, a( 1, j*nb+1 ), lda,
322 $ work( nb+1 ), n,
323 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
324* T(J,J) += U(J,J)'*T(J,J-1)*U(J-1,J)
325 CALL zgemm( 'Conjugate transpose', 'NoTranspose',
326 $ kb, nb, kb,
327 $ one, a( (j-1)*nb+1, j*nb+1 ), lda,
328 $ tb( td+nb+1 + ((j-1)*nb)*ldtb ), ldtb-1,
329 $ zero, work( 1 ), n )
330 CALL zgemm( 'NoTranspose', 'NoTranspose',
331 $ kb, kb, nb,
332 $ -one, work( 1 ), n,
333 $ a( (j-2)*nb+1, j*nb+1 ), lda,
334 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
335 END IF
336 IF( j.GT.0 ) THEN
337 CALL zhegst( 1, 'Upper', kb,
338 $ tb( td+1 + (j*nb)*ldtb ), ldtb-1,
339 $ a( (j-1)*nb+1, j*nb+1 ), lda, iinfo )
340 END IF
341*
342* Expand T(J,J) into full format
343*
344 DO i = 1, kb
345 tb( td+1 + (j*nb+i-1)*ldtb )
346 $ = real( tb( td+1 + (j*nb+i-1)*ldtb ) )
347 DO k = i+1, kb
348 tb( td+(k-i)+1 + (j*nb+i-1)*ldtb )
349 $ = dconjg( tb( td-(k-(i+1)) + (j*nb+k-1)*ldtb ) )
350 END DO
351 END DO
352*
353 IF( j.LT.nt-1 ) THEN
354 IF( j.GT.0 ) THEN
355*
356* Compute H(J,J)
357*
358 IF( j.EQ.1 ) THEN
359 CALL zgemm( 'NoTranspose', 'NoTranspose',
360 $ kb, kb, kb,
361 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1,
362 $ a( (j-1)*nb+1, j*nb+1 ), lda,
363 $ zero, work( j*nb+1 ), n )
364 ELSE
365 CALL zgemm( 'NoTranspose', 'NoTranspose',
366 $ kb, kb, nb+kb,
367 $ one, tb( td+nb+1 + ((j-1)*nb)*ldtb ),
368 $ ldtb-1,
369 $ a( (j-2)*nb+1, j*nb+1 ), lda,
370 $ zero, work( j*nb+1 ), n )
371 END IF
372*
373* Update with the previous column
374*
375 CALL zgemm( 'Conjugate transpose', 'NoTranspose',
376 $ nb, n-(j+1)*nb, j*nb,
377 $ -one, work( nb+1 ), n,
378 $ a( 1, (j+1)*nb+1 ), lda,
379 $ one, a( j*nb+1, (j+1)*nb+1 ), lda )
380 END IF
381*
382* Copy panel to workspace to call ZGETRF
383*
384 DO k = 1, nb
385 CALL zcopy( n-(j+1)*nb,
386 $ a( j*nb+k, (j+1)*nb+1 ), lda,
387 $ work( 1+(k-1)*n ), 1 )
388 END DO
389*
390* Factorize panel
391*
392 CALL zgetrf( n-(j+1)*nb, nb,
393 $ work, n,
394 $ ipiv( (j+1)*nb+1 ), iinfo )
395c IF (IINFO.NE.0 .AND. INFO.EQ.0) THEN
396c INFO = IINFO+(J+1)*NB
397c END IF
398*
399* Copy panel back
400*
401 DO k = 1, nb
402*
403* Copy only L-factor
404*
405 CALL zcopy( n-k-(j+1)*nb,
406 $ work( k+1+(k-1)*n ), 1,
407 $ a( j*nb+k, (j+1)*nb+k+1 ), lda )
408*
409* Transpose U-factor to be copied back into T(J+1, J)
410*
411 CALL zlacgv( k, work( 1+(k-1)*n ), 1 )
412 END DO
413*
414* Compute T(J+1, J), zero out for GEMM update
415*
416 kb = min(nb, n-(j+1)*nb)
417 CALL zlaset( 'Full', kb, nb, zero, zero,
418 $ tb( td+nb+1 + (j*nb)*ldtb) , ldtb-1 )
419 CALL zlacpy( 'Upper', kb, nb,
420 $ work, n,
421 $ tb( td+nb+1 + (j*nb)*ldtb ), ldtb-1 )
422 IF( j.GT.0 ) THEN
423 CALL ztrsm( 'R', 'U', 'N', 'U', kb, nb, one,
424 $ a( (j-1)*nb+1, j*nb+1 ), lda,
425 $ tb( td+nb+1 + (j*nb)*ldtb ), ldtb-1 )
426 END IF
427*
428* Copy T(J,J+1) into T(J+1, J), both upper/lower for GEMM
429* updates
430*
431 DO k = 1, nb
432 DO i = 1, kb
433 tb( td-nb+k-i+1 + (j*nb+nb+i-1)*ldtb )
434 $ = dconjg( tb( td+nb+i-k+1 + (j*nb+k-1)*ldtb ) )
435 END DO
436 END DO
437 CALL zlaset( 'Lower', kb, nb, zero, one,
438 $ a( j*nb+1, (j+1)*nb+1), lda )
439*
440* Apply pivots to trailing submatrix of A
441*
442 DO k = 1, kb
443* > Adjust ipiv
444 ipiv( (j+1)*nb+k ) = ipiv( (j+1)*nb+k ) + (j+1)*nb
445*
446 i1 = (j+1)*nb+k
447 i2 = ipiv( (j+1)*nb+k )
448 IF( i1.NE.i2 ) THEN
449* > Apply pivots to previous columns of L
450 CALL zswap( k-1, a( (j+1)*nb+1, i1 ), 1,
451 $ a( (j+1)*nb+1, i2 ), 1 )
452* > Swap A(I1+1:M, I1) with A(I2, I1+1:M)
453 IF( i2.GT.(i1+1) ) THEN
454 CALL zswap( i2-i1-1, a( i1, i1+1 ), lda,
455 $ a( i1+1, i2 ), 1 )
456 CALL zlacgv( i2-i1-1, a( i1+1, i2 ), 1 )
457 END IF
458 CALL zlacgv( i2-i1, a( i1, i1+1 ), lda )
459* > Swap A(I2+1:M, I1) with A(I2+1:M, I2)
460 IF( i2.LT.n )
461 $ CALL zswap( n-i2, a( i1, i2+1 ), lda,
462 $ a( i2, i2+1 ), lda )
463* > Swap A(I1, I1) with A(I2, I2)
464 piv = a( i1, i1 )
465 a( i1, i1 ) = a( i2, i2 )
466 a( i2, i2 ) = piv
467* > Apply pivots to previous columns of L
468 IF( j.GT.0 ) THEN
469 CALL zswap( j*nb, a( 1, i1 ), 1,
470 $ a( 1, i2 ), 1 )
471 END IF
472 ENDIF
473 END DO
474 END IF
475 END DO
476 ELSE
477*
478* .....................................................
479* Factorize A as L*D*L**H using the lower triangle of A
480* .....................................................
481*
482 DO j = 0, nt-1
483*
484* Generate Jth column of W and H
485*
486 kb = min(nb, n-j*nb)
487 DO i = 1, j-1
488 IF( i.EQ.1 ) THEN
489* H(I,J) = T(I,I)*L(J,I)' + T(I+1,I)'*L(J,I+1)'
490 IF( i .EQ. (j-1) ) THEN
491 jb = nb+kb
492 ELSE
493 jb = 2*nb
494 END IF
495 CALL zgemm( 'NoTranspose', 'Conjugate transpose',
496 $ nb, kb, jb,
497 $ one, tb( td+1 + (i*nb)*ldtb ), ldtb-1,
498 $ a( j*nb+1, (i-1)*nb+1 ), lda,
499 $ zero, work( i*nb+1 ), n )
500 ELSE
501* H(I,J) = T(I,I-1)*L(J,I-1)' + T(I,I)*L(J,I)' + T(I,I+1)*L(J,I+1)'
502 IF( i .EQ. (j-1) ) THEN
503 jb = 2*nb+kb
504 ELSE
505 jb = 3*nb
506 END IF
507 CALL zgemm( 'NoTranspose', 'Conjugate transpose',
508 $ nb, kb, jb,
509 $ one, tb( td+nb+1 + ((i-1)*nb)*ldtb ),
510 $ ldtb-1,
511 $ a( j*nb+1, (i-2)*nb+1 ), lda,
512 $ zero, work( i*nb+1 ), n )
513 END IF
514 END DO
515*
516* Compute T(J,J)
517*
518 CALL zlacpy( 'Lower', kb, kb, a( j*nb+1, j*nb+1 ), lda,
519 $ tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
520 IF( j.GT.1 ) THEN
521* T(J,J) = L(J,1:J)*H(1:J)
522 CALL zgemm( 'NoTranspose', 'NoTranspose',
523 $ kb, kb, (j-1)*nb,
524 $ -one, a( j*nb+1, 1 ), lda,
525 $ work( nb+1 ), n,
526 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
527* T(J,J) += L(J,J)*T(J,J-1)*L(J,J-1)'
528 CALL zgemm( 'NoTranspose', 'NoTranspose',
529 $ kb, nb, kb,
530 $ one, a( j*nb+1, (j-1)*nb+1 ), lda,
531 $ tb( td+nb+1 + ((j-1)*nb)*ldtb ), ldtb-1,
532 $ zero, work( 1 ), n )
533 CALL zgemm( 'NoTranspose', 'Conjugate transpose',
534 $ kb, kb, nb,
535 $ -one, work( 1 ), n,
536 $ a( j*nb+1, (j-2)*nb+1 ), lda,
537 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1 )
538 END IF
539 IF( j.GT.0 ) THEN
540 CALL zhegst( 1, 'Lower', kb,
541 $ tb( td+1 + (j*nb)*ldtb ), ldtb-1,
542 $ a( j*nb+1, (j-1)*nb+1 ), lda, iinfo )
543 END IF
544*
545* Expand T(J,J) into full format
546*
547 DO i = 1, kb
548 tb( td+1 + (j*nb+i-1)*ldtb )
549 $ = real( tb( td+1 + (j*nb+i-1)*ldtb ) )
550 DO k = i+1, kb
551 tb( td-(k-(i+1)) + (j*nb+k-1)*ldtb )
552 $ = dconjg( tb( td+(k-i)+1 + (j*nb+i-1)*ldtb ) )
553 END DO
554 END DO
555*
556 IF( j.LT.nt-1 ) THEN
557 IF( j.GT.0 ) THEN
558*
559* Compute H(J,J)
560*
561 IF( j.EQ.1 ) THEN
562 CALL zgemm( 'NoTranspose', 'Conjugate transpose',
563 $ kb, kb, kb,
564 $ one, tb( td+1 + (j*nb)*ldtb ), ldtb-1,
565 $ a( j*nb+1, (j-1)*nb+1 ), lda,
566 $ zero, work( j*nb+1 ), n )
567 ELSE
568 CALL zgemm( 'notranspose', 'conjugate transpose',
569 $ KB, KB, NB+KB,
570 $ ONE, TB( TD+NB+1 + ((J-1)*NB)*LDTB ),
571 $ LDTB-1,
572 $ A( J*NB+1, (J-2)*NB+1 ), LDA,
573 $ ZERO, WORK( J*NB+1 ), N )
574 END IF
575*
576* Update with the previous column
577*
578 CALL ZGEMM( 'notranspose', 'notranspose',
579 $ N-(J+1)*NB, NB, J*NB,
580 $ -ONE, A( (J+1)*NB+1, 1 ), LDA,
581 $ WORK( NB+1 ), N,
582 $ ONE, A( (J+1)*NB+1, J*NB+1 ), LDA )
583 END IF
584*
585* Factorize panel
586*
587 CALL ZGETRF( N-(J+1)*NB, NB,
588 $ A( (J+1)*NB+1, J*NB+1 ), LDA,
589 $ IPIV( (J+1)*NB+1 ), IINFO )
590c IF (IINFO.NE.0 .AND. INFO.EQ.0) THEN
591c INFO = IINFO+(J+1)*NB
592c END IF
593*
594* Compute T(J+1, J), zero out for GEMM update
595*
596 KB = MIN(NB, N-(J+1)*NB)
597 CALL ZLASET( 'full', KB, NB, ZERO, ZERO,
598 $ TB( TD+NB+1 + (J*NB)*LDTB) , LDTB-1 )
599 CALL ZLACPY( 'upper', KB, NB,
600 $ A( (J+1)*NB+1, J*NB+1 ), LDA,
601 $ TB( TD+NB+1 + (J*NB)*LDTB ), LDTB-1 )
602.GT. IF( J0 ) THEN
603 CALL ZTRSM( 'r', 'l', 'c', 'u', KB, NB, ONE,
604 $ A( J*NB+1, (J-1)*NB+1 ), LDA,
605 $ TB( TD+NB+1 + (J*NB)*LDTB ), LDTB-1 )
606 END IF
607*
608* Copy T(J+1,J) into T(J, J+1), both upper/lower for GEMM
609* updates
610*
611 DO K = 1, NB
612 DO I = 1, KB
613 TB( TD-NB+K-I+1 + (J*NB+NB+I-1)*LDTB )
614 $ = DCONJG( TB( TD+NB+I-K+1 + (J*NB+K-1)*LDTB ) )
615 END DO
616 END DO
617 CALL ZLASET( 'upper', KB, NB, ZERO, ONE,
618 $ A( (J+1)*NB+1, J*NB+1), LDA )
619*
620* Apply pivots to trailing submatrix of A
621*
622 DO K = 1, KB
623* > Adjust ipiv
624 IPIV( (J+1)*NB+K ) = IPIV( (J+1)*NB+K ) + (J+1)*NB
625*
626 I1 = (J+1)*NB+K
627 I2 = IPIV( (J+1)*NB+K )
628.NE. IF( I1I2 ) THEN
629* > Apply pivots to previous columns of L
630 CALL ZSWAP( K-1, A( I1, (J+1)*NB+1 ), LDA,
631 $ A( I2, (J+1)*NB+1 ), LDA )
632* > Swap A(I1+1:M, I1) with A(I2, I1+1:M)
633.GT. IF( I2(I1+1) ) THEN
634 CALL ZSWAP( I2-I1-1, A( I1+1, I1 ), 1,
635 $ A( I2, I1+1 ), LDA )
636 CALL ZLACGV( I2-I1-1, A( I2, I1+1 ), LDA )
637 END IF
638 CALL ZLACGV( I2-I1, A( I1+1, I1 ), 1 )
639* > Swap A(I2+1:M, I1) with A(I2+1:M, I2)
640.LT. IF( I2N )
641 $ CALL ZSWAP( N-I2, A( I2+1, I1 ), 1,
642 $ A( I2+1, I2 ), 1 )
643* > Swap A(I1, I1) with A(I2, I2)
644 PIV = A( I1, I1 )
645 A( I1, I1 ) = A( I2, I2 )
646 A( I2, I2 ) = PIV
647* > Apply pivots to previous columns of L
648.GT. IF( J0 ) THEN
649 CALL ZSWAP( J*NB, A( I1, 1 ), LDA,
650 $ A( I2, 1 ), LDA )
651 END IF
652 ENDIF
653 END DO
654*
655* Apply pivots to previous columns of L
656*
657c CALL ZLASWP( J*NB, A( 1, 1 ), LDA,
658c $ (J+1)*NB+1, (J+1)*NB+KB, IPIV, 1 )
659 END IF
660 END DO
661 END IF
662*
663* Factor the band matrix
664 CALL ZGBTRF( N, N, NB, NB, TB, LDTB, IPIV2, INFO )
665*
666 RETURN
667*
668* End of ZHETRF_AA_2STAGE
669*
670 END
xerbla
subroutine xerbla(srname, info)
XERBLA
Definition xerbla.f:60
zgbtrf
subroutine zgbtrf(m, n, kl, ku, ab, ldab, ipiv, info)
ZGBTRF
Definition zgbtrf.f:144
zhegst
subroutine zhegst(itype, uplo, n, a, lda, b, ldb, info)
ZHEGST
Definition zhegst.f:128
zlacpy
subroutine zlacpy(uplo, m, n, a, lda, b, ldb)
ZLACPY copies all or part of one two-dimensional array to another.
Definition zlacpy.f:103
zlacgv
subroutine zlacgv(n, x, incx)
ZLACGV conjugates a complex vector.
Definition zlacgv.f:74
zlaset
subroutine zlaset(uplo, m, n, alpha, beta, a, lda)
ZLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
Definition zlaset.f:106
zhetrf_aa_2stage
subroutine zhetrf_aa_2stage(uplo, n, a, lda, tb, ltb, ipiv, ipiv2, work, lwork, info)
ZHETRF_AA_2STAGE
Definition zhetrf_aa_2stage.f:160
zswap
subroutine zswap(n, zx, incx, zy, incy)
ZSWAP
Definition zswap.f:81
zcopy
subroutine zcopy(n, zx, incx, zy, incy)
ZCOPY
Definition zcopy.f:81
zgemm
subroutine zgemm(transa, transb, m, n, k, alpha, a, lda, b, ldb, beta, c, ldc)
ZGEMM
Definition zgemm.f:187
ztrsm
subroutine ztrsm(side, uplo, transa, diag, m, n, alpha, a, lda, b, ldb)
ZTRSM
Definition ztrsm.f:180
zgetrf
subroutine zgetrf(m, n, a, lda, ipiv, info)
ZGETRF VARIANT: Crout Level 3 BLAS version of the algorithm.
Definition zgetrf.f:102
min
#define min(a, b)
Definition macros.h:20
max
#define max(a, b)
Definition macros.h:21