clarfb.f 23 KB

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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