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1*> \brief \b CLARFB
2*
3*  =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6*            http://www.netlib.org/lapack/explore-html/
7*
8*> \htmlonly
9*> Download CLARFB + dependencies
10*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/clarfb.f">
11*> [TGZ]</a>
12*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/clarfb.f">
13*> [ZIP]</a>
14*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/clarfb.f">
15*> [TXT]</a>
16*> \endhtmlonly
17*
18*  Definition:
19*  ===========
20*
21*       SUBROUTINE CLARFB( 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*       COMPLEX            C( LDC, * ), T( LDT, * ), V( LDV, * ),
30*      $                   WORK( LDWORK, * )
31*       ..
32*
33*
34*> \par Purpose:
35*  =============
36*>
37*> \verbatim
38*>
39*> CLARFB applies a complex block reflector H or its transpose H**H to a
40*> complex 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**H from the Left
50*>          = 'R': apply H or H**H from the Right
51*> \endverbatim
52*>
53*> \param[in] TRANS
54*> \verbatim
55*>          TRANS is CHARACTER*1
56*>          = 'N': apply H (No transpose)
57*>          = 'C': apply H**H (Conjugate 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 COMPLEX 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 COMPLEX 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 COMPLEX array, dimension (LDC,N)
131*>          On entry, the M-by-N matrix C.
132*>          On exit, C is overwritten by H*C or H**H*C or C*H or C*H**H.
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 COMPLEX 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 complexOTHERauxiliary
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 CLARFB( 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      COMPLEX            C( LDC, * ), T( LDT, * ), V( LDV, * ),
209     $                   WORK( LDWORK, * )
210*     ..
211*
212*  =====================================================================
213*
214*     .. Parameters ..
215      COMPLEX            ONE
216      PARAMETER          ( ONE = ( 1.0E+0, 0.0E+0 ) )
217*     ..
218*     .. Local Scalars ..
219      CHARACTER          TRANST
220      INTEGER            I, J, LASTV, LASTC
221*     ..
222*     .. External Functions ..
223      LOGICAL            LSAME
224      INTEGER            ILACLR, ILACLC
225      EXTERNAL           LSAME, ILACLR, ILACLC
226*     ..
227*     .. External Subroutines ..
228      EXTERNAL           CCOPY, CGEMM, CLACGV, CTRMM
229*     ..
230*     .. Intrinsic Functions ..
231      INTRINSIC          CONJG
232*     ..
233*     .. Executable Statements ..
234*
235*     Quick return if possible
236*
237      IF( M.LE.0 .OR. N.LE.0 )
238     $   RETURN
239*
240      IF( LSAME( TRANS, 'N' ) ) THEN
241         TRANST = 'C'
242      ELSE
243         TRANST = 'N'
244      END IF
245*
246      IF( LSAME( STOREV, 'C' ) ) THEN
247*
248         IF( LSAME( DIRECT, 'F' ) ) THEN
249*
250*           Let  V =  ( V1 )    (first K rows)
251*                     ( V2 )
252*           where  V1  is unit lower triangular.
253*
254            IF( LSAME( SIDE, 'L' ) ) THEN
255*
256*              Form  H * C  or  H**H * C  where  C = ( C1 )
257*                                                    ( C2 )
258*
259               LASTV = MAX( K, ILACLR( M, K, V, LDV ) )
260               LASTC = ILACLC( LASTV, N, C, LDC )
261*
262*              W := C**H * V  =  (C1**H * V1 + C2**H * V2)  (stored in WORK)
263*
264*              W := C1**H
265*
266               DO 10 J = 1, K
267                  CALL CCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
268                  CALL CLACGV( LASTC, WORK( 1, J ), 1 )
269   10          CONTINUE
270*
271*              W := W * V1
272*
273               CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
274     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
275               IF( LASTV.GT.K ) THEN
276*
277*                 W := W + C2**H *V2
278*
279                  CALL CGEMM( 'Conjugate transpose', 'No transpose',
280     $                 LASTC, K, LASTV-K, ONE, C( K+1, 1 ), LDC,
281     $                 V( K+1, 1 ), LDV, ONE, WORK, LDWORK )
282               END IF
283*
284*              W := W * T**H  or  W * T
285*
286               CALL CTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
287     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
288*
289*              C := C - V * W**H
290*
291               IF( M.GT.K ) THEN
292*
293*                 C2 := C2 - V2 * W**H
294*
295                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
296     $                 LASTV-K, LASTC, K, -ONE, V( K+1, 1 ), LDV,
297     $                 WORK, LDWORK, ONE, C( K+1, 1 ), LDC )
298               END IF
299*
300*              W := W * V1**H
301*
302               CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
303     $              'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
304*
305*              C1 := C1 - W**H
306*
307               DO 30 J = 1, K
308                  DO 20 I = 1, LASTC
309                     C( J, I ) = C( J, I ) - CONJG( WORK( I, J ) )
310   20             CONTINUE
311   30          CONTINUE
312*
313            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
314*
315*              Form  C * H  or  C * H**H  where  C = ( C1  C2 )
316*
317               LASTV = MAX( K, ILACLR( N, K, V, LDV ) )
318               LASTC = ILACLR( M, LASTV, C, LDC )
319*
320*              W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)
321*
322*              W := C1
323*
324               DO 40 J = 1, K
325                  CALL CCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
326   40          CONTINUE
327*
328*              W := W * V1
329*
330               CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
331     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
332               IF( LASTV.GT.K ) THEN
333*
334*                 W := W + C2 * V2
335*
336                  CALL CGEMM( 'No transpose', 'No transpose',
337     $                 LASTC, K, LASTV-K,
338     $                 ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV,
339     $                 ONE, WORK, LDWORK )
340               END IF
341*
342*              W := W * T  or  W * T**H
343*
344               CALL CTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
345     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
346*
347*              C := C - W * V**H
348*
349               IF( LASTV.GT.K ) THEN
350*
351*                 C2 := C2 - W * V2**H
352*
353                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
354     $                 LASTC, LASTV-K, K,
355     $                 -ONE, WORK, LDWORK, V( K+1, 1 ), LDV,
356     $                 ONE, C( 1, K+1 ), LDC )
357               END IF
358*
359*              W := W * V1**H
360*
361               CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
362     $              'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
363*
364*              C1 := C1 - W
365*
366               DO 60 J = 1, K
367                  DO 50 I = 1, LASTC
368                     C( I, J ) = C( I, J ) - WORK( I, J )
369   50             CONTINUE
370   60          CONTINUE
371            END IF
372*
373         ELSE
374*
375*           Let  V =  ( V1 )
376*                     ( V2 )    (last K rows)
377*           where  V2  is unit upper triangular.
378*
379            IF( LSAME( SIDE, 'L' ) ) THEN
380*
381*              Form  H * C  or  H**H * C  where  C = ( C1 )
382*                                                    ( C2 )
383*
384               LASTV = MAX( K, ILACLR( M, K, V, LDV ) )
385               LASTC = ILACLC( LASTV, N, C, LDC )
386*
387*              W := C**H * V  =  (C1**H * V1 + C2**H * V2)  (stored in WORK)
388*
389*              W := C2**H
390*
391               DO 70 J = 1, K
392                  CALL CCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
393     $                 WORK( 1, J ), 1 )
394                  CALL CLACGV( LASTC, WORK( 1, J ), 1 )
395   70          CONTINUE
396*
397*              W := W * V2
398*
399               CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
400     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
401     $              WORK, LDWORK )
402               IF( LASTV.GT.K ) THEN
403*
404*                 W := W + C1**H*V1
405*
406                  CALL CGEMM( 'Conjugate transpose', 'No transpose',
407     $                 LASTC, K, LASTV-K, ONE, C, LDC, V, LDV,
408     $                 ONE, WORK, LDWORK )
409               END IF
410*
411*              W := W * T**H  or  W * T
412*
413               CALL CTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
414     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
415*
416*              C := C - V * W**H
417*
418               IF( LASTV.GT.K ) THEN
419*
420*                 C1 := C1 - V1 * W**H
421*
422                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
423     $                 LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
424     $                 ONE, C, LDC )
425               END IF
426*
427*              W := W * V2**H
428*
429               CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
430     $              'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
431     $              WORK, LDWORK )
432*
433*              C2 := C2 - W**H
434*
435               DO 90 J = 1, K
436                  DO 80 I = 1, LASTC
437                     C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
438     $                               CONJG( WORK( I, J ) )
439   80             CONTINUE
440   90          CONTINUE
441*
442            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
443*
444*              Form  C * H  or  C * H**H  where  C = ( C1  C2 )
445*
446               LASTV = MAX( K, ILACLR( N, K, V, LDV ) )
447               LASTC = ILACLR( M, LASTV, C, LDC )
448*
449*              W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)
450*
451*              W := C2
452*
453               DO 100 J = 1, K
454                  CALL CCOPY( LASTC, C( 1, LASTV-K+J ), 1,
455     $                 WORK( 1, J ), 1 )
456  100          CONTINUE
457*
458*              W := W * V2
459*
460               CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
461     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
462     $              WORK, LDWORK )
463               IF( LASTV.GT.K ) THEN
464*
465*                 W := W + C1 * V1
466*
467                  CALL CGEMM( 'No transpose', 'No transpose',
468     $                 LASTC, K, LASTV-K,
469     $                 ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
470               END IF
471*
472*              W := W * T  or  W * T**H
473*
474               CALL CTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
475     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
476*
477*              C := C - W * V**H
478*
479               IF( LASTV.GT.K ) THEN
480*
481*                 C1 := C1 - W * V1**H
482*
483                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
484     $                 LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
485     $                 ONE, C, LDC )
486               END IF
487*
488*              W := W * V2**H
489*
490               CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
491     $              'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
492     $              WORK, LDWORK )
493*
494*              C2 := C2 - W
495*
496               DO 120 J = 1, K
497                  DO 110 I = 1, LASTC
498                     C( I, LASTV-K+J ) = C( I, LASTV-K+J )
499     $                    - WORK( I, J )
500  110             CONTINUE
501  120          CONTINUE
502            END IF
503         END IF
504*
505      ELSE IF( LSAME( STOREV, 'R' ) ) THEN
506*
507         IF( LSAME( DIRECT, 'F' ) ) THEN
508*
509*           Let  V =  ( V1  V2 )    (V1: first K columns)
510*           where  V1  is unit upper triangular.
511*
512            IF( LSAME( SIDE, 'L' ) ) THEN
513*
514*              Form  H * C  or  H**H * C  where  C = ( C1 )
515*                                                    ( C2 )
516*
517               LASTV = MAX( K, ILACLC( K, M, V, LDV ) )
518               LASTC = ILACLC( LASTV, N, C, LDC )
519*
520*              W := C**H * V**H  =  (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
521*
522*              W := C1**H
523*
524               DO 130 J = 1, K
525                  CALL CCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
526                  CALL CLACGV( LASTC, WORK( 1, J ), 1 )
527  130          CONTINUE
528*
529*              W := W * V1**H
530*
531               CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
532     $                     'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
533               IF( LASTV.GT.K ) THEN
534*
535*                 W := W + C2**H*V2**H
536*
537                  CALL CGEMM( 'Conjugate transpose',
538     $                 'Conjugate transpose', LASTC, K, LASTV-K,
539     $                 ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
540     $                 ONE, WORK, LDWORK )
541               END IF
542*
543*              W := W * T**H  or  W * T
544*
545               CALL CTRMM( 'Right', 'Upper', TRANST, 'Non-unit',
546     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
547*
548*              C := C - V**H * W**H
549*
550               IF( LASTV.GT.K ) THEN
551*
552*                 C2 := C2 - V2**H * W**H
553*
554                  CALL CGEMM( 'Conjugate transpose',
555     $                 'Conjugate transpose', LASTV-K, LASTC, K,
556     $                 -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
557     $                 ONE, C( K+1, 1 ), LDC )
558               END IF
559*
560*              W := W * V1
561*
562               CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
563     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
564*
565*              C1 := C1 - W**H
566*
567               DO 150 J = 1, K
568                  DO 140 I = 1, LASTC
569                     C( J, I ) = C( J, I ) - CONJG( WORK( I, J ) )
570  140             CONTINUE
571  150          CONTINUE
572*
573            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
574*
575*              Form  C * H  or  C * H**H  where  C = ( C1  C2 )
576*
577               LASTV = MAX( K, ILACLC( K, N, V, LDV ) )
578               LASTC = ILACLR( M, LASTV, C, LDC )
579*
580*              W := C * V**H  =  (C1*V1**H + C2*V2**H)  (stored in WORK)
581*
582*              W := C1
583*
584               DO 160 J = 1, K
585                  CALL CCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
586  160          CONTINUE
587*
588*              W := W * V1**H
589*
590               CALL CTRMM( 'Right', 'Upper', 'Conjugate transpose',
591     $                     'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK )
592               IF( LASTV.GT.K ) THEN
593*
594*                 W := W + C2 * V2**H
595*
596                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
597     $                 LASTC, K, LASTV-K, ONE, C( 1, K+1 ), LDC,
598     $                 V( 1, K+1 ), LDV, ONE, WORK, LDWORK )
599               END IF
600*
601*              W := W * T  or  W * T**H
602*
603               CALL CTRMM( 'Right', 'Upper', TRANS, 'Non-unit',
604     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
605*
606*              C := C - W * V
607*
608               IF( LASTV.GT.K ) THEN
609*
610*                 C2 := C2 - W * V2
611*
612                  CALL CGEMM( 'No transpose', 'No transpose',
613     $                 LASTC, LASTV-K, K,
614     $                 -ONE, WORK, LDWORK, V( 1, K+1 ), LDV,
615     $                 ONE, C( 1, K+1 ), LDC )
616               END IF
617*
618*              W := W * V1
619*
620               CALL CTRMM( 'Right', 'Upper', 'No transpose', 'Unit',
621     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
622*
623*              C1 := C1 - W
624*
625               DO 180 J = 1, K
626                  DO 170 I = 1, LASTC
627                     C( I, J ) = C( I, J ) - WORK( I, J )
628  170             CONTINUE
629  180          CONTINUE
630*
631            END IF
632*
633         ELSE
634*
635*           Let  V =  ( V1  V2 )    (V2: last K columns)
636*           where  V2  is unit lower triangular.
637*
638            IF( LSAME( SIDE, 'L' ) ) THEN
639*
640*              Form  H * C  or  H**H * C  where  C = ( C1 )
641*                                                    ( C2 )
642*
643               LASTV = MAX( K, ILACLC( K, M, V, LDV ) )
644               LASTC = ILACLC( LASTV, N, C, LDC )
645*
646*              W := C**H * V**H  =  (C1**H * V1**H + C2**H * V2**H) (stored in WORK)
647*
648*              W := C2**H
649*
650               DO 190 J = 1, K
651                  CALL CCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
652     $                 WORK( 1, J ), 1 )
653                  CALL CLACGV( LASTC, WORK( 1, J ), 1 )
654  190          CONTINUE
655*
656*              W := W * V2**H
657*
658               CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
659     $              'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
660     $              WORK, LDWORK )
661               IF( LASTV.GT.K ) THEN
662*
663*                 W := W + C1**H * V1**H
664*
665                  CALL CGEMM( 'Conjugate transpose',
666     $                 'Conjugate transpose', LASTC, K, LASTV-K,
667     $                 ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
668               END IF
669*
670*              W := W * T**H  or  W * T
671*
672               CALL CTRMM( 'Right', 'Lower', TRANST, 'Non-unit',
673     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
674*
675*              C := C - V**H * W**H
676*
677               IF( LASTV.GT.K ) THEN
678*
679*                 C1 := C1 - V1**H * W**H
680*
681                  CALL CGEMM( 'Conjugate transpose',
682     $                 'Conjugate transpose', LASTV-K, LASTC, K,
683     $                 -ONE, V, LDV, WORK, LDWORK, ONE, C, LDC )
684               END IF
685*
686*              W := W * V2
687*
688               CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
689     $              LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
690     $              WORK, LDWORK )
691*
692*              C2 := C2 - W**H
693*
694               DO 210 J = 1, K
695                  DO 200 I = 1, LASTC
696                     C( LASTV-K+J, I ) = C( LASTV-K+J, I ) -
697     $                               CONJG( WORK( I, J ) )
698  200             CONTINUE
699  210          CONTINUE
700*
701            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
702*
703*              Form  C * H  or  C * H**H  where  C = ( C1  C2 )
704*
705               LASTV = MAX( K, ILACLC( K, N, V, LDV ) )
706               LASTC = ILACLR( M, LASTV, C, LDC )
707*
708*              W := C * V**H  =  (C1*V1**H + C2*V2**H)  (stored in WORK)
709*
710*              W := C2
711*
712               DO 220 J = 1, K
713                  CALL CCOPY( LASTC, C( 1, LASTV-K+J ), 1,
714     $                 WORK( 1, J ), 1 )
715  220          CONTINUE
716*
717*              W := W * V2**H
718*
719               CALL CTRMM( 'Right', 'Lower', 'Conjugate transpose',
720     $              'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
721     $              WORK, LDWORK )
722               IF( LASTV.GT.K ) THEN
723*
724*                 W := W + C1 * V1**H
725*
726                  CALL CGEMM( 'No transpose', 'Conjugate transpose',
727     $                 LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, ONE,
728     $                 WORK, LDWORK )
729               END IF
730*
731*              W := W * T  or  W * T**H
732*
733               CALL CTRMM( 'Right', 'Lower', TRANS, 'Non-unit',
734     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
735*
736*              C := C - W * V
737*
738               IF( LASTV.GT.K ) THEN
739*
740*                 C1 := C1 - W * V1
741*
742                  CALL CGEMM( 'No transpose', 'No transpose',
743     $                 LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
744     $                 ONE, C, LDC )
745               END IF
746*
747*              W := W * V2
748*
749               CALL CTRMM( 'Right', 'Lower', 'No transpose', 'Unit',
750     $              LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV,
751     $              WORK, LDWORK )
752*
753*              C1 := C1 - W
754*
755               DO 240 J = 1, K
756                  DO 230 I = 1, LASTC
757                     C( I, LASTV-K+J ) = C( I, LASTV-K+J )
758     $                    - WORK( I, J )
759  230             CONTINUE
760  240          CONTINUE
761*
762            END IF
763*
764         END IF
765      END IF
766*
767      RETURN
768*
769*     End of CLARFB
770*
771      END
772