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realtimeroboticsgroup.org / RealtimeRoboticsGroup / test / a57b70145cb0a950c1c3a9a4fddf0438c60126f2 / . / third_party / eigen / lapack / slarfb.f
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Brian Silverman72890c22015-09-19 14:37:37 -0400[diff] [blame]1*> \brief \b SLARFB
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
9*> Download SLARFB + dependencies
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarfb.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarfb.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarfb.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18* Definition:
19* ===========
20*
21* SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
22* T, LDT, C, LDC, WORK, LDWORK )
23*
24* .. Scalar Arguments ..
25* CHARACTER DIRECT, SIDE, STOREV, TRANS
26* INTEGER K, LDC, LDT, LDV, LDWORK, M, N
27* ..
28* .. Array Arguments ..
29* REAL C( LDC, * ), T( LDT, * ), V( LDV, * ),
30* $ WORK( LDWORK, * )
31* ..
32*
33*
34*> \par Purpose:
35* =============
36*>
37*> \verbatim
38*>
39*> SLARFB applies a real block reflector H or its transpose H**T to a
40*> real m by n matrix C, from either the left or the right.
41*> \endverbatim
42*
43* Arguments:
44* ==========
45*
46*> \param[in] SIDE
47*> \verbatim
48*> SIDE is CHARACTER*1
49*> = 'L': apply H or H**T from the Left
50*> = 'R': apply H or H**T from the Right
51*> \endverbatim
52*>
53*> \param[in] TRANS
54*> \verbatim
55*> TRANS is CHARACTER*1
56*> = 'N': apply H (No transpose)
57*> = 'T': apply H**T (Transpose)
58*> \endverbatim
59*>
60*> \param[in] DIRECT
61*> \verbatim
62*> DIRECT is CHARACTER*1
63*> Indicates how H is formed from a product of elementary
64*> reflectors
65*> = 'F': H = H(1) H(2) . . . H(k) (Forward)
66*> = 'B': H = H(k) . . . H(2) H(1) (Backward)
67*> \endverbatim
68*>
69*> \param[in] STOREV
70*> \verbatim
71*> STOREV is CHARACTER*1
72*> Indicates how the vectors which define the elementary
73*> reflectors are stored:
74*> = 'C': Columnwise
75*> = 'R': Rowwise
76*> \endverbatim
77*>
78*> \param[in] M
79*> \verbatim
80*> M is INTEGER
81*> The number of rows of the matrix C.
82*> \endverbatim
83*>
84*> \param[in] N
85*> \verbatim
86*> N is INTEGER
87*> The number of columns of the matrix C.
88*> \endverbatim
89*>
90*> \param[in] K
91*> \verbatim
92*> K is INTEGER
93*> The order of the matrix T (= the number of elementary
94*> reflectors whose product defines the block reflector).
95*> \endverbatim
96*>
97*> \param[in] V
98*> \verbatim
99*> V is REAL array, dimension
100*> (LDV,K) if STOREV = 'C'
101*> (LDV,M) if STOREV = 'R' and SIDE = 'L'
102*> (LDV,N) if STOREV = 'R' and SIDE = 'R'
103*> The matrix V. See Further Details.
104*> \endverbatim
105*>
106*> \param[in] LDV
107*> \verbatim
108*> LDV is INTEGER
109*> The leading dimension of the array V.
110*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
111*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
112*> if STOREV = 'R', LDV >= K.
113*> \endverbatim
114*>
115*> \param[in] T
116*> \verbatim
117*> T is REAL array, dimension (LDT,K)
118*> The triangular k by k matrix T in the representation of the
119*> block reflector.
120*> \endverbatim
121*>
122*> \param[in] LDT
123*> \verbatim
124*> LDT is INTEGER
125*> The leading dimension of the array T. LDT >= K.
126*> \endverbatim
127*>
128*> \param[in,out] C
129*> \verbatim
130*> C is REAL array, dimension (LDC,N)
131*> On entry, the m by n matrix C.
132*> On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.
133*> \endverbatim
134*>
135*> \param[in] LDC
136*> \verbatim
137*> LDC is INTEGER
138*> The leading dimension of the array C. LDC >= max(1,M).
139*> \endverbatim
140*>
141*> \param[out] WORK
142*> \verbatim
143*> WORK is REAL array, dimension (LDWORK,K)
144*> \endverbatim
145*>
146*> \param[in] LDWORK
147*> \verbatim
148*> LDWORK is INTEGER
149*> The leading dimension of the array WORK.
150*> If SIDE = 'L', LDWORK >= max(1,N);
151*> if SIDE = 'R', LDWORK >= max(1,M).
152*> \endverbatim
153*
154* Authors:
155* ========
156*
157*> \author Univ. of Tennessee
158*> \author Univ. of California Berkeley
159*> \author Univ. of Colorado Denver
160*> \author NAG Ltd.
161*
162*> \date November 2011
163*
164*> \ingroup realOTHERauxiliary
165*
166*> \par Further Details:
167* =====================
168*>
169*> \verbatim
170*>
171*> The shape of the matrix V and the storage of the vectors which define
172*> the H(i) is best illustrated by the following example with n = 5 and
173*> k = 3. The elements equal to 1 are not stored; the corresponding
174*> array elements are modified but restored on exit. The rest of the
175*> array is not used.
176*>
177*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R':
178*>
179*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 )
180*> ( v1 1 ) ( 1 v2 v2 v2 )
181*> ( v1 v2 1 ) ( 1 v3 v3 )
182*> ( v1 v2 v3 )
183*> ( v1 v2 v3 )
184*>
185*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R':
186*>
187*> V = ( v1 v2 v3 ) V = ( v1 v1 1 )
188*> ( v1 v2 v3 ) ( v2 v2 v2 1 )
189*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 )
190*> ( 1 v3 )
191*> ( 1 )
192*> \endverbatim
193*>
194* =====================================================================
195 SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
196 $ T, LDT, C, LDC, WORK, LDWORK )
197*
198* -- LAPACK auxiliary routine (version 3.4.0) --
199* -- LAPACK is a software package provided by Univ. of Tennessee, --
200* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
201* November 2011
202*
203* .. Scalar Arguments ..
204 CHARACTER DIRECT, SIDE, STOREV, TRANS
205 INTEGER K, LDC, LDT, LDV, LDWORK, M, N
206* ..
207* .. Array Arguments ..
208 REAL C( LDC, * ), T( LDT, * ), V( LDV, * ),
209 $ WORK( LDWORK, * )
210* ..
211*
212* =====================================================================
213*
214* .. Parameters ..
215 REAL ONE
216 PARAMETER ( ONE = 1.0E+0 )
217* ..
218* .. Local Scalars ..
219 CHARACTER TRANST
220 INTEGER I, J, LASTV, LASTC
221* ..
222* .. External Functions ..
223 LOGICAL LSAME
224 INTEGER ILASLR, ILASLC
225 EXTERNAL LSAME, ILASLR, ILASLC
226* ..
227* .. External Subroutines ..
228 EXTERNAL SCOPY, SGEMM, STRMM
229* ..
230* .. Executable Statements ..
231*
232* Quick return if possible
233*
234 IF( M.LE.0 .OR. N.LE.0 )
235 $ RETURN
236*
237 IF( LSAME( TRANS, 'N' ) ) THEN
238 TRANST = 'T'
239 ELSE
240 TRANST = 'N'
241 END IF
242*
243 IF( LSAME( STOREV, 'C' ) ) THEN
244*
245 IF( LSAME( DIRECT, 'F' ) ) THEN
246*
247* Let V = ( V1 ) (first K rows)
248* ( V2 )
249* where V1 is unit lower triangular.
250*
251 IF( LSAME( SIDE, 'L' ) ) THEN
252*
253* Form H * C or H**T * C where C = ( C1 )
254* ( C2 )
255*
256 LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
257 LASTC = ILASLC( LASTV, N, C, LDC )
258*
259* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
260*
261* W := C1**T
262*
263 DO 10 J = 1, K
264 CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
265 10 CONTINUE
266*
267* W := W * V1
268*
269 CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
270 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
271 IF( LASTV.GT.K ) THEN
272*
273* W := W + C2**T *V2
274*
275 CALL SGEMM( 'Transpose', 'No transpose',
276 $ LASTC, K, LASTV-K,
277 $ ONE, C( K+1, 1 ), LDC, V( K+1, 1 ), LDV,
278 $ ONE, WORK, LDWORK )
279 END IF
280*
281* W := W * T**T or W * T
282*
283 CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
284 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
285*
286* C := C - V * W**T
287*
288 IF( LASTV.GT.K ) THEN
289*
290* C2 := C2 - V2 * W**T
291*
292 CALL SGEMM( 'No transpose', 'Transpose',
293 $ LASTV-K, LASTC, K,
294 $ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, ONE,
295 $ C( K+1, 1 ), LDC )
296 END IF
297*
298* W := W * V1**T
299*
300 CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
301 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
302*
303* C1 := C1 - W**T
304*
305 DO 30 J = 1, K
306 DO 20 I = 1, LASTC
307 C( J, I ) = C( J, I ) - WORK( I, J )
308 20 CONTINUE
309 30 CONTINUE
310*
311 ELSE IF( LSAME( SIDE, 'R' ) ) THEN
312*
313* Form C * H or C * H**T where C = ( C1 C2 )
314*
315 LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
316 LASTC = ILASLR( M, LASTV, C, LDC )
317*
318* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
319*
320* W := C1
321*
322 DO 40 J = 1, K
323 CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
324 40 CONTINUE
325*
326* W := W * V1
327*
328 CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
329 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
330 IF( LASTV.GT.K ) THEN
331*
332* W := W + C2 * V2
333*
334 CALL SGEMM( 'No transpose', 'No transpose',
335 $ LASTC, K, LASTV-K,
336 $ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
337 $ ONE, WORK, LDWORK )
338 END IF
339*
340* W := W * T or W * T**T
341*
342 CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit',
343 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
344*
345* C := C - W * V**T
346*
347 IF( LASTV.GT.K ) THEN
348*
349* C2 := C2 - W * V2**T
350*
351 CALL SGEMM( 'No transpose', 'Transpose',
352 $ LASTC, LASTV-K, K,
353 $ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, ONE,
354 $ C( 1, K+1 ), LDC )
355 END IF
356*
357* W := W * V1**T
358*
359 CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
360 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
361*
362* C1 := C1 - W
363*
364 DO 60 J = 1, K
365 DO 50 I = 1, LASTC
366 C( I, J ) = C( I, J ) - WORK( I, J )
367 50 CONTINUE
368 60 CONTINUE
369 END IF
370*
371 ELSE
372*
373* Let V = ( V1 )
374* ( V2 ) (last K rows)
375* where V2 is unit upper triangular.
376*
377 IF( LSAME( SIDE, 'L' ) ) THEN
378*
379* Form H * C or H**T * C where C = ( C1 )
380* ( C2 )
381*
382 LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
383 LASTC = ILASLC( LASTV, N, C, LDC )
384*
385* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK)
386*
387* W := C2**T
388*
389 DO 70 J = 1, K
390 CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
391 $ WORK( 1, J ), 1 )
392 70 CONTINUE
393*
394* W := W * V2
395*
396 CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
397 $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
398 $ WORK, LDWORK )
399 IF( LASTV.GT.K ) THEN
400*
401* W := W + C1**T*V1
402*
403 CALL SGEMM( 'Transpose', 'No transpose',
404 $ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
405 $ ONE, WORK, LDWORK )
406 END IF
407*
408* W := W * T**T or W * T
409*
410 CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit',
411 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
412*
413* C := C - V * W**T
414*
415 IF( LASTV.GT.K ) THEN
416*
417* C1 := C1 - V1 * W**T
418*
419 CALL SGEMM( 'No transpose', 'Transpose',
420 $ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
421 $ ONE, C, LDC )
422 END IF
423*
424* W := W * V2**T
425*
426 CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
427 $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
428 $ WORK, LDWORK )
429*
430* C2 := C2 - W**T
431*
432 DO 90 J = 1, K
433 DO 80 I = 1, LASTC
434 C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
435 80 CONTINUE
436 90 CONTINUE
437*
438 ELSE IF( LSAME( SIDE, 'R' ) ) THEN
439*
440* Form C * H or C * H**T where C = ( C1 C2 )
441*
442 LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
443 LASTC = ILASLR( M, LASTV, C, LDC )
444*
445* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
446*
447* W := C2
448*
449 DO 100 J = 1, K
450 CALL SCOPY( LASTC, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
451 100 CONTINUE
452*
453* W := W * V2
454*
455 CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
456 $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
457 $ WORK, LDWORK )
458 IF( LASTV.GT.K ) THEN
459*
460* W := W + C1 * V1
461*
462 CALL SGEMM( 'No transpose', 'No transpose',
463 $ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
464 $ ONE, WORK, LDWORK )
465 END IF
466*
467* W := W * T or W * T**T
468*
469 CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit',
470 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
471*
472* C := C - W * V**T
473*
474 IF( LASTV.GT.K ) THEN
475*
476* C1 := C1 - W * V1**T
477*
478 CALL SGEMM( 'No transpose', 'Transpose',
479 $ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
480 $ ONE, C, LDC )
481 END IF
482*
483* W := W * V2**T
484*
485 CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
486 $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
487 $ WORK, LDWORK )
488*
489* C2 := C2 - W
490*
491 DO 120 J = 1, K
492 DO 110 I = 1, LASTC
493 C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J)
494 110 CONTINUE
495 120 CONTINUE
496 END IF
497 END IF
498*
499 ELSE IF( LSAME( STOREV, 'R' ) ) THEN
500*
501 IF( LSAME( DIRECT, 'F' ) ) THEN
502*
503* Let V = ( V1 V2 ) (V1: first K columns)
504* where V1 is unit upper triangular.
505*
506 IF( LSAME( SIDE, 'L' ) ) THEN
507*
508* Form H * C or H**T * C where C = ( C1 )
509* ( C2 )
510*
511 LASTV = MAX( K, ILASLC( K, M, V, LDV ) )
512 LASTC = ILASLC( LASTV, N, C, LDC )
513*
514* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
515*
516* W := C1**T
517*
518 DO 130 J = 1, K
519 CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
520 130 CONTINUE
521*
522* W := W * V1**T
523*
524 CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
525 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
526 IF( LASTV.GT.K ) THEN
527*
528* W := W + C2**T*V2**T
529*
530 CALL SGEMM( 'Transpose', 'Transpose',
531 $ LASTC, K, LASTV-K,
532 $ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
533 $ ONE, WORK, LDWORK )
534 END IF
535*
536* W := W * T**T or W * T
537*
538 CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
539 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
540*
541* C := C - V**T * W**T
542*
543 IF( LASTV.GT.K ) THEN
544*
545* C2 := C2 - V2**T * W**T
546*
547 CALL SGEMM( 'Transpose', 'Transpose',
548 $ LASTV-K, LASTC, K,
549 $ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
550 $ ONE, C( K+1, 1 ), LDC )
551 END IF
552*
553* W := W * V1
554*
555 CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
556 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
557*
558* C1 := C1 - W**T
559*
560 DO 150 J = 1, K
561 DO 140 I = 1, LASTC
562 C( J, I ) = C( J, I ) - WORK( I, J )
563 140 CONTINUE
564 150 CONTINUE
565*
566 ELSE IF( LSAME( SIDE, 'R' ) ) THEN
567*
568* Form C * H or C * H**T where C = ( C1 C2 )
569*
570 LASTV = MAX( K, ILASLC( K, N, V, LDV ) )
571 LASTC = ILASLR( M, LASTV, C, LDC )
572*
573* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
574*
575* W := C1
576*
577 DO 160 J = 1, K
578 CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
579 160 CONTINUE
580*
581* W := W * V1**T
582*
583 CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
584 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
585 IF( LASTV.GT.K ) THEN
586*
587* W := W + C2 * V2**T
588*
589 CALL SGEMM( 'No transpose', 'Transpose',
590 $ LASTC, K, LASTV-K,
591 $ ONE, C( 1, K+1 ), LDC, V( 1, K+1 ), LDV,
592 $ ONE, WORK, LDWORK )
593 END IF
594*
595* W := W * T or W * T**T
596*
597 CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit',
598 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
599*
600* C := C - W * V
601*
602 IF( LASTV.GT.K ) THEN
603*
604* C2 := C2 - W * V2
605*
606 CALL SGEMM( 'No transpose', 'No transpose',
607 $ LASTC, LASTV-K, K,
608 $ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
609 $ ONE, C( 1, K+1 ), LDC )
610 END IF
611*
612* W := W * V1
613*
614 CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
615 $ LASTC, K, ONE, V, LDV, WORK, LDWORK )
616*
617* C1 := C1 - W
618*
619 DO 180 J = 1, K
620 DO 170 I = 1, LASTC
621 C( I, J ) = C( I, J ) - WORK( I, J )
622 170 CONTINUE
623 180 CONTINUE
624*
625 END IF
626*
627 ELSE
628*
629* Let V = ( V1 V2 ) (V2: last K columns)
630* where V2 is unit lower triangular.
631*
632 IF( LSAME( SIDE, 'L' ) ) THEN
633*
634* Form H * C or H**T * C where C = ( C1 )
635* ( C2 )
636*
637 LASTV = MAX( K, ILASLC( K, M, V, LDV ) )
638 LASTC = ILASLC( LASTV, N, C, LDC )
639*
640* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK)
641*
642* W := C2**T
643*
644 DO 190 J = 1, K
645 CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
646 $ WORK( 1, J ), 1 )
647 190 CONTINUE
648*
649* W := W * V2**T
650*
651 CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
652 $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
653 $ WORK, LDWORK )
654 IF( LASTV.GT.K ) THEN
655*
656* W := W + C1**T * V1**T
657*
658 CALL SGEMM( 'Transpose', 'Transpose',
659 $ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
660 $ ONE, WORK, LDWORK )
661 END IF
662*
663* W := W * T**T or W * T
664*
665 CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit',
666 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
667*
668* C := C - V**T * W**T
669*
670 IF( LASTV.GT.K ) THEN
671*
672* C1 := C1 - V1**T * W**T
673*
674 CALL SGEMM( 'Transpose', 'Transpose',
675 $ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
676 $ ONE, C, LDC )
677 END IF
678*
679* W := W * V2
680*
681 CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
682 $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
683 $ WORK, LDWORK )
684*
685* C2 := C2 - W**T
686*
687 DO 210 J = 1, K
688 DO 200 I = 1, LASTC
689 C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
690 200 CONTINUE
691 210 CONTINUE
692*
693 ELSE IF( LSAME( SIDE, 'R' ) ) THEN
694*
695* Form C * H or C * H**T where C = ( C1 C2 )
696*
697 LASTV = MAX( K, ILASLC( K, N, V, LDV ) )
698 LASTC = ILASLR( M, LASTV, C, LDC )
699*
700* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK)
701*
702* W := C2
703*
704 DO 220 J = 1, K
705 CALL SCOPY( LASTC, C( 1, LASTV-K+J ), 1,
706 $ WORK( 1, J ), 1 )
707 220 CONTINUE
708*
709* W := W * V2**T
710*
711 CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
712 $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
713 $ WORK, LDWORK )
714 IF( LASTV.GT.K ) THEN
715*
716* W := W + C1 * V1**T
717*
718 CALL SGEMM( 'No transpose', 'Transpose',
719 $ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
720 $ ONE, WORK, LDWORK )
721 END IF
722*
723* W := W * T or W * T**T
724*
725 CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit',
726 $ LASTC, K, ONE, T, LDT, WORK, LDWORK )
727*
728* C := C - W * V
729*
730 IF( LASTV.GT.K ) THEN
731*
732* C1 := C1 - W * V1
733*
734 CALL SGEMM( 'No transpose', 'No transpose',
735 $ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
736 $ ONE, C, LDC )
737 END IF
738*
739* W := W * V2
740*
741 CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
742 $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
743 $ WORK, LDWORK )
744*
745* C1 := C1 - W
746*
747 DO 240 J = 1, K
748 DO 230 I = 1, LASTC
749 C( I, LASTV-K+J ) = C( I, LASTV-K+J )
750 $ - WORK( I, J )
751 230 CONTINUE
752 240 CONTINUE
753*
754 END IF
755*
756 END IF
757 END IF
758*
759 RETURN
760*
761* End of SLARFB
762*
763 END