Brian Silverman | 72890c2 | 2015-09-19 14:37:37 -0400 | [diff] [blame] | 1 | *> \brief \b ZLARFB |
| 2 | * |
| 3 | * =========== DOCUMENTATION =========== |
| 4 | * |
| 5 | * Online html documentation available at |
| 6 | * http://www.netlib.org/lapack/explore-html/ |
| 7 | * |
| 8 | *> \htmlonly |
| 9 | *> Download ZLARFB + dependencies |
| 10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlarfb.f"> |
| 11 | *> [TGZ]</a> |
| 12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlarfb.f"> |
| 13 | *> [ZIP]</a> |
| 14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlarfb.f"> |
| 15 | *> [TXT]</a> |
| 16 | *> \endhtmlonly |
| 17 | * |
| 18 | * Definition: |
| 19 | * =========== |
| 20 | * |
| 21 | * SUBROUTINE ZLARFB( 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*16 C( LDC, * ), T( LDT, * ), V( LDV, * ), |
| 30 | * $ WORK( LDWORK, * ) |
| 31 | * .. |
| 32 | * |
| 33 | * |
| 34 | *> \par Purpose: |
| 35 | * ============= |
| 36 | *> |
| 37 | *> \verbatim |
| 38 | *> |
| 39 | *> ZLARFB 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*16 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 | *> 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*16 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*16 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*16 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 complex16OTHERauxiliary |
| 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 ZLARFB( 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*16 C( LDC, * ), T( LDT, * ), V( LDV, * ), |
| 209 | $ WORK( LDWORK, * ) |
| 210 | * .. |
| 211 | * |
| 212 | * ===================================================================== |
| 213 | * |
| 214 | * .. Parameters .. |
| 215 | COMPLEX*16 ONE |
| 216 | PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) ) |
| 217 | * .. |
| 218 | * .. Local Scalars .. |
| 219 | CHARACTER TRANST |
| 220 | INTEGER I, J, LASTV, LASTC |
| 221 | * .. |
| 222 | * .. External Functions .. |
| 223 | LOGICAL LSAME |
| 224 | INTEGER ILAZLR, ILAZLC |
| 225 | EXTERNAL LSAME, ILAZLR, ILAZLC |
| 226 | * .. |
| 227 | * .. External Subroutines .. |
| 228 | EXTERNAL ZCOPY, ZGEMM, ZLACGV, ZTRMM |
| 229 | * .. |
| 230 | * .. Intrinsic Functions .. |
| 231 | INTRINSIC DCONJG |
| 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, ILAZLR( M, K, V, LDV ) ) |
| 260 | LASTC = ILAZLC( 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 ZCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 ) |
| 268 | CALL ZLACGV( LASTC, WORK( 1, J ), 1 ) |
| 269 | 10 CONTINUE |
| 270 | * |
| 271 | * W := W * V1 |
| 272 | * |
| 273 | CALL ZTRMM( '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 ZGEMM( '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 ZTRMM( '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 ZGEMM( 'No transpose', 'Conjugate transpose', |
| 296 | $ LASTV-K, LASTC, K, |
| 297 | $ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, |
| 298 | $ ONE, C( K+1, 1 ), LDC ) |
| 299 | END IF |
| 300 | * |
| 301 | * W := W * V1**H |
| 302 | * |
| 303 | CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose', |
| 304 | $ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 305 | * |
| 306 | * C1 := C1 - W**H |
| 307 | * |
| 308 | DO 30 J = 1, K |
| 309 | DO 20 I = 1, LASTC |
| 310 | C( J, I ) = C( J, I ) - DCONJG( WORK( I, J ) ) |
| 311 | 20 CONTINUE |
| 312 | 30 CONTINUE |
| 313 | * |
| 314 | ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
| 315 | * |
| 316 | * Form C * H or C * H**H where C = ( C1 C2 ) |
| 317 | * |
| 318 | LASTV = MAX( K, ILAZLR( N, K, V, LDV ) ) |
| 319 | LASTC = ILAZLR( M, LASTV, C, LDC ) |
| 320 | * |
| 321 | * W := C * V = (C1*V1 + C2*V2) (stored in WORK) |
| 322 | * |
| 323 | * W := C1 |
| 324 | * |
| 325 | DO 40 J = 1, K |
| 326 | CALL ZCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 ) |
| 327 | 40 CONTINUE |
| 328 | * |
| 329 | * W := W * V1 |
| 330 | * |
| 331 | CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
| 332 | $ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 333 | IF( LASTV.GT.K ) THEN |
| 334 | * |
| 335 | * W := W + C2 * V2 |
| 336 | * |
| 337 | CALL ZGEMM( 'No transpose', 'No transpose', |
| 338 | $ LASTC, K, LASTV-K, |
| 339 | $ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV, |
| 340 | $ ONE, WORK, LDWORK ) |
| 341 | END IF |
| 342 | * |
| 343 | * W := W * T or W * T**H |
| 344 | * |
| 345 | CALL ZTRMM( 'Right', 'Upper', TRANS, 'Non-unit', |
| 346 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 347 | * |
| 348 | * C := C - W * V**H |
| 349 | * |
| 350 | IF( LASTV.GT.K ) THEN |
| 351 | * |
| 352 | * C2 := C2 - W * V2**H |
| 353 | * |
| 354 | CALL ZGEMM( 'No transpose', 'Conjugate transpose', |
| 355 | $ LASTC, LASTV-K, K, |
| 356 | $ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, |
| 357 | $ ONE, C( 1, K+1 ), LDC ) |
| 358 | END IF |
| 359 | * |
| 360 | * W := W * V1**H |
| 361 | * |
| 362 | CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose', |
| 363 | $ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 364 | * |
| 365 | * C1 := C1 - W |
| 366 | * |
| 367 | DO 60 J = 1, K |
| 368 | DO 50 I = 1, LASTC |
| 369 | C( I, J ) = C( I, J ) - WORK( I, J ) |
| 370 | 50 CONTINUE |
| 371 | 60 CONTINUE |
| 372 | END IF |
| 373 | * |
| 374 | ELSE |
| 375 | * |
| 376 | * Let V = ( V1 ) |
| 377 | * ( V2 ) (last K rows) |
| 378 | * where V2 is unit upper triangular. |
| 379 | * |
| 380 | IF( LSAME( SIDE, 'L' ) ) THEN |
| 381 | * |
| 382 | * Form H * C or H**H * C where C = ( C1 ) |
| 383 | * ( C2 ) |
| 384 | * |
| 385 | LASTV = MAX( K, ILAZLR( M, K, V, LDV ) ) |
| 386 | LASTC = ILAZLC( LASTV, N, C, LDC ) |
| 387 | * |
| 388 | * W := C**H * V = (C1**H * V1 + C2**H * V2) (stored in WORK) |
| 389 | * |
| 390 | * W := C2**H |
| 391 | * |
| 392 | DO 70 J = 1, K |
| 393 | CALL ZCOPY( LASTC, C( LASTV-K+J, 1 ), LDC, |
| 394 | $ WORK( 1, J ), 1 ) |
| 395 | CALL ZLACGV( LASTC, WORK( 1, J ), 1 ) |
| 396 | 70 CONTINUE |
| 397 | * |
| 398 | * W := W * V2 |
| 399 | * |
| 400 | CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
| 401 | $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
| 402 | $ WORK, LDWORK ) |
| 403 | IF( LASTV.GT.K ) THEN |
| 404 | * |
| 405 | * W := W + C1**H*V1 |
| 406 | * |
| 407 | CALL ZGEMM( 'Conjugate transpose', 'No transpose', |
| 408 | $ LASTC, K, LASTV-K, |
| 409 | $ ONE, C, LDC, V, LDV, |
| 410 | $ ONE, WORK, LDWORK ) |
| 411 | END IF |
| 412 | * |
| 413 | * W := W * T**H or W * T |
| 414 | * |
| 415 | CALL ZTRMM( 'Right', 'Lower', TRANST, 'Non-unit', |
| 416 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 417 | * |
| 418 | * C := C - V * W**H |
| 419 | * |
| 420 | IF( LASTV.GT.K ) THEN |
| 421 | * |
| 422 | * C1 := C1 - V1 * W**H |
| 423 | * |
| 424 | CALL ZGEMM( 'No transpose', 'Conjugate transpose', |
| 425 | $ LASTV-K, LASTC, K, |
| 426 | $ -ONE, V, LDV, WORK, LDWORK, |
| 427 | $ ONE, C, LDC ) |
| 428 | END IF |
| 429 | * |
| 430 | * W := W * V2**H |
| 431 | * |
| 432 | CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose', |
| 433 | $ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
| 434 | $ WORK, LDWORK ) |
| 435 | * |
| 436 | * C2 := C2 - W**H |
| 437 | * |
| 438 | DO 90 J = 1, K |
| 439 | DO 80 I = 1, LASTC |
| 440 | C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - |
| 441 | $ DCONJG( WORK( I, J ) ) |
| 442 | 80 CONTINUE |
| 443 | 90 CONTINUE |
| 444 | * |
| 445 | ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
| 446 | * |
| 447 | * Form C * H or C * H**H where C = ( C1 C2 ) |
| 448 | * |
| 449 | LASTV = MAX( K, ILAZLR( N, K, V, LDV ) ) |
| 450 | LASTC = ILAZLR( M, LASTV, C, LDC ) |
| 451 | * |
| 452 | * W := C * V = (C1*V1 + C2*V2) (stored in WORK) |
| 453 | * |
| 454 | * W := C2 |
| 455 | * |
| 456 | DO 100 J = 1, K |
| 457 | CALL ZCOPY( LASTC, C( 1, LASTV-K+J ), 1, |
| 458 | $ WORK( 1, J ), 1 ) |
| 459 | 100 CONTINUE |
| 460 | * |
| 461 | * W := W * V2 |
| 462 | * |
| 463 | CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
| 464 | $ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
| 465 | $ WORK, LDWORK ) |
| 466 | IF( LASTV.GT.K ) THEN |
| 467 | * |
| 468 | * W := W + C1 * V1 |
| 469 | * |
| 470 | CALL ZGEMM( 'No transpose', 'No transpose', |
| 471 | $ LASTC, K, LASTV-K, |
| 472 | $ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK ) |
| 473 | END IF |
| 474 | * |
| 475 | * W := W * T or W * T**H |
| 476 | * |
| 477 | CALL ZTRMM( 'Right', 'Lower', TRANS, 'Non-unit', |
| 478 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 479 | * |
| 480 | * C := C - W * V**H |
| 481 | * |
| 482 | IF( LASTV.GT.K ) THEN |
| 483 | * |
| 484 | * C1 := C1 - W * V1**H |
| 485 | * |
| 486 | CALL ZGEMM( 'No transpose', 'Conjugate transpose', |
| 487 | $ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV, |
| 488 | $ ONE, C, LDC ) |
| 489 | END IF |
| 490 | * |
| 491 | * W := W * V2**H |
| 492 | * |
| 493 | CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose', |
| 494 | $ 'Unit', LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
| 495 | $ WORK, LDWORK ) |
| 496 | * |
| 497 | * C2 := C2 - W |
| 498 | * |
| 499 | DO 120 J = 1, K |
| 500 | DO 110 I = 1, LASTC |
| 501 | C( I, LASTV-K+J ) = C( I, LASTV-K+J ) |
| 502 | $ - WORK( I, J ) |
| 503 | 110 CONTINUE |
| 504 | 120 CONTINUE |
| 505 | END IF |
| 506 | END IF |
| 507 | * |
| 508 | ELSE IF( LSAME( STOREV, 'R' ) ) THEN |
| 509 | * |
| 510 | IF( LSAME( DIRECT, 'F' ) ) THEN |
| 511 | * |
| 512 | * Let V = ( V1 V2 ) (V1: first K columns) |
| 513 | * where V1 is unit upper triangular. |
| 514 | * |
| 515 | IF( LSAME( SIDE, 'L' ) ) THEN |
| 516 | * |
| 517 | * Form H * C or H**H * C where C = ( C1 ) |
| 518 | * ( C2 ) |
| 519 | * |
| 520 | LASTV = MAX( K, ILAZLC( K, M, V, LDV ) ) |
| 521 | LASTC = ILAZLC( LASTV, N, C, LDC ) |
| 522 | * |
| 523 | * W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK) |
| 524 | * |
| 525 | * W := C1**H |
| 526 | * |
| 527 | DO 130 J = 1, K |
| 528 | CALL ZCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 ) |
| 529 | CALL ZLACGV( LASTC, WORK( 1, J ), 1 ) |
| 530 | 130 CONTINUE |
| 531 | * |
| 532 | * W := W * V1**H |
| 533 | * |
| 534 | CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose', |
| 535 | $ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 536 | IF( LASTV.GT.K ) THEN |
| 537 | * |
| 538 | * W := W + C2**H*V2**H |
| 539 | * |
| 540 | CALL ZGEMM( 'Conjugate transpose', |
| 541 | $ 'Conjugate transpose', LASTC, K, LASTV-K, |
| 542 | $ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV, |
| 543 | $ ONE, WORK, LDWORK ) |
| 544 | END IF |
| 545 | * |
| 546 | * W := W * T**H or W * T |
| 547 | * |
| 548 | CALL ZTRMM( 'Right', 'Upper', TRANST, 'Non-unit', |
| 549 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 550 | * |
| 551 | * C := C - V**H * W**H |
| 552 | * |
| 553 | IF( LASTV.GT.K ) THEN |
| 554 | * |
| 555 | * C2 := C2 - V2**H * W**H |
| 556 | * |
| 557 | CALL ZGEMM( 'Conjugate transpose', |
| 558 | $ 'Conjugate transpose', LASTV-K, LASTC, K, |
| 559 | $ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK, |
| 560 | $ ONE, C( K+1, 1 ), LDC ) |
| 561 | END IF |
| 562 | * |
| 563 | * W := W * V1 |
| 564 | * |
| 565 | CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
| 566 | $ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 567 | * |
| 568 | * C1 := C1 - W**H |
| 569 | * |
| 570 | DO 150 J = 1, K |
| 571 | DO 140 I = 1, LASTC |
| 572 | C( J, I ) = C( J, I ) - DCONJG( WORK( I, J ) ) |
| 573 | 140 CONTINUE |
| 574 | 150 CONTINUE |
| 575 | * |
| 576 | ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
| 577 | * |
| 578 | * Form C * H or C * H**H where C = ( C1 C2 ) |
| 579 | * |
| 580 | LASTV = MAX( K, ILAZLC( K, N, V, LDV ) ) |
| 581 | LASTC = ILAZLR( M, LASTV, C, LDC ) |
| 582 | * |
| 583 | * W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK) |
| 584 | * |
| 585 | * W := C1 |
| 586 | * |
| 587 | DO 160 J = 1, K |
| 588 | CALL ZCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 ) |
| 589 | 160 CONTINUE |
| 590 | * |
| 591 | * W := W * V1**H |
| 592 | * |
| 593 | CALL ZTRMM( 'Right', 'Upper', 'Conjugate transpose', |
| 594 | $ 'Unit', LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 595 | IF( LASTV.GT.K ) THEN |
| 596 | * |
| 597 | * W := W + C2 * V2**H |
| 598 | * |
| 599 | CALL ZGEMM( 'No transpose', 'Conjugate transpose', |
| 600 | $ LASTC, K, LASTV-K, ONE, C( 1, K+1 ), LDC, |
| 601 | $ V( 1, K+1 ), LDV, ONE, WORK, LDWORK ) |
| 602 | END IF |
| 603 | * |
| 604 | * W := W * T or W * T**H |
| 605 | * |
| 606 | CALL ZTRMM( 'Right', 'Upper', TRANS, 'Non-unit', |
| 607 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 608 | * |
| 609 | * C := C - W * V |
| 610 | * |
| 611 | IF( LASTV.GT.K ) THEN |
| 612 | * |
| 613 | * C2 := C2 - W * V2 |
| 614 | * |
| 615 | CALL ZGEMM( 'No transpose', 'No transpose', |
| 616 | $ LASTC, LASTV-K, K, |
| 617 | $ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV, |
| 618 | $ ONE, C( 1, K+1 ), LDC ) |
| 619 | END IF |
| 620 | * |
| 621 | * W := W * V1 |
| 622 | * |
| 623 | CALL ZTRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
| 624 | $ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
| 625 | * |
| 626 | * C1 := C1 - W |
| 627 | * |
| 628 | DO 180 J = 1, K |
| 629 | DO 170 I = 1, LASTC |
| 630 | C( I, J ) = C( I, J ) - WORK( I, J ) |
| 631 | 170 CONTINUE |
| 632 | 180 CONTINUE |
| 633 | * |
| 634 | END IF |
| 635 | * |
| 636 | ELSE |
| 637 | * |
| 638 | * Let V = ( V1 V2 ) (V2: last K columns) |
| 639 | * where V2 is unit lower triangular. |
| 640 | * |
| 641 | IF( LSAME( SIDE, 'L' ) ) THEN |
| 642 | * |
| 643 | * Form H * C or H**H * C where C = ( C1 ) |
| 644 | * ( C2 ) |
| 645 | * |
| 646 | LASTV = MAX( K, ILAZLC( K, M, V, LDV ) ) |
| 647 | LASTC = ILAZLC( LASTV, N, C, LDC ) |
| 648 | * |
| 649 | * W := C**H * V**H = (C1**H * V1**H + C2**H * V2**H) (stored in WORK) |
| 650 | * |
| 651 | * W := C2**H |
| 652 | * |
| 653 | DO 190 J = 1, K |
| 654 | CALL ZCOPY( LASTC, C( LASTV-K+J, 1 ), LDC, |
| 655 | $ WORK( 1, J ), 1 ) |
| 656 | CALL ZLACGV( LASTC, WORK( 1, J ), 1 ) |
| 657 | 190 CONTINUE |
| 658 | * |
| 659 | * W := W * V2**H |
| 660 | * |
| 661 | CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose', |
| 662 | $ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
| 663 | $ WORK, LDWORK ) |
| 664 | IF( LASTV.GT.K ) THEN |
| 665 | * |
| 666 | * W := W + C1**H * V1**H |
| 667 | * |
| 668 | CALL ZGEMM( 'Conjugate transpose', |
| 669 | $ 'Conjugate transpose', LASTC, K, LASTV-K, |
| 670 | $ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK ) |
| 671 | END IF |
| 672 | * |
| 673 | * W := W * T**H or W * T |
| 674 | * |
| 675 | CALL ZTRMM( 'Right', 'Lower', TRANST, 'Non-unit', |
| 676 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 677 | * |
| 678 | * C := C - V**H * W**H |
| 679 | * |
| 680 | IF( LASTV.GT.K ) THEN |
| 681 | * |
| 682 | * C1 := C1 - V1**H * W**H |
| 683 | * |
| 684 | CALL ZGEMM( 'Conjugate transpose', |
| 685 | $ 'Conjugate transpose', LASTV-K, LASTC, K, |
| 686 | $ -ONE, V, LDV, WORK, LDWORK, ONE, C, LDC ) |
| 687 | END IF |
| 688 | * |
| 689 | * W := W * V2 |
| 690 | * |
| 691 | CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
| 692 | $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
| 693 | $ WORK, LDWORK ) |
| 694 | * |
| 695 | * C2 := C2 - W**H |
| 696 | * |
| 697 | DO 210 J = 1, K |
| 698 | DO 200 I = 1, LASTC |
| 699 | C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - |
| 700 | $ DCONJG( WORK( I, J ) ) |
| 701 | 200 CONTINUE |
| 702 | 210 CONTINUE |
| 703 | * |
| 704 | ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
| 705 | * |
| 706 | * Form C * H or C * H**H where C = ( C1 C2 ) |
| 707 | * |
| 708 | LASTV = MAX( K, ILAZLC( K, N, V, LDV ) ) |
| 709 | LASTC = ILAZLR( M, LASTV, C, LDC ) |
| 710 | * |
| 711 | * W := C * V**H = (C1*V1**H + C2*V2**H) (stored in WORK) |
| 712 | * |
| 713 | * W := C2 |
| 714 | * |
| 715 | DO 220 J = 1, K |
| 716 | CALL ZCOPY( LASTC, C( 1, LASTV-K+J ), 1, |
| 717 | $ WORK( 1, J ), 1 ) |
| 718 | 220 CONTINUE |
| 719 | * |
| 720 | * W := W * V2**H |
| 721 | * |
| 722 | CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose', |
| 723 | $ 'Unit', LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
| 724 | $ WORK, LDWORK ) |
| 725 | IF( LASTV.GT.K ) THEN |
| 726 | * |
| 727 | * W := W + C1 * V1**H |
| 728 | * |
| 729 | CALL ZGEMM( 'No transpose', 'Conjugate transpose', |
| 730 | $ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, ONE, |
| 731 | $ WORK, LDWORK ) |
| 732 | END IF |
| 733 | * |
| 734 | * W := W * T or W * T**H |
| 735 | * |
| 736 | CALL ZTRMM( 'Right', 'Lower', TRANS, 'Non-unit', |
| 737 | $ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
| 738 | * |
| 739 | * C := C - W * V |
| 740 | * |
| 741 | IF( LASTV.GT.K ) THEN |
| 742 | * |
| 743 | * C1 := C1 - W * V1 |
| 744 | * |
| 745 | CALL ZGEMM( 'No transpose', 'No transpose', |
| 746 | $ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV, |
| 747 | $ ONE, C, LDC ) |
| 748 | END IF |
| 749 | * |
| 750 | * W := W * V2 |
| 751 | * |
| 752 | CALL ZTRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
| 753 | $ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
| 754 | $ WORK, LDWORK ) |
| 755 | * |
| 756 | * C1 := C1 - W |
| 757 | * |
| 758 | DO 240 J = 1, K |
| 759 | DO 230 I = 1, LASTC |
| 760 | C( I, LASTV-K+J ) = C( I, LASTV-K+J ) |
| 761 | $ - WORK( I, J ) |
| 762 | 230 CONTINUE |
| 763 | 240 CONTINUE |
| 764 | * |
| 765 | END IF |
| 766 | * |
| 767 | END IF |
| 768 | END IF |
| 769 | * |
| 770 | RETURN |
| 771 | * |
| 772 | * End of ZLARFB |
| 773 | * |
| 774 | END |