Annotation of rpl/lapack/lapack/ztpmlqt.f, revision 1.4

1.1       bertrand    1: *> \brief \b ZTPMLQT
                      2: *
                      3: *  =========== DOCUMENTATION ===========
                      4: *
                      5: * Online html documentation available at
                      6: *            http://www.netlib.org/lapack/explore-html/
                      7: *
                      8: *> \htmlonly
1.3       bertrand    9: *> Download ZTPMLQT + dependencies
1.1       bertrand   10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ztpmlqt.f">
                     11: *> [TGZ]</a>
                     12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ztpmlqt.f">
                     13: *> [ZIP]</a>
                     14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ztpmlqt.f">
                     15: *> [TXT]</a>
                     16: *> \endhtmlonly
                     17: *
                     18: *  Definition:
                     19: *  ===========
                     20: *
                     21: *       SUBROUTINE ZTPMLQT( SIDE, TRANS, M, N, K, L, MB, V, LDV, T, LDT,
                     22: *                           A, LDA, B, LDB, WORK, INFO )
                     23: *
                     24: *       .. Scalar Arguments ..
                     25: *       CHARACTER SIDE, TRANS
                     26: *       INTEGER   INFO, K, LDV, LDA, LDB, M, N, L, MB, LDT
                     27: *       ..
                     28: *       .. Array Arguments ..
                     29: *       COMPLEX*16         V( LDV, * ), A( LDA, * ), B( LDB, * ),
                     30: *      $                   T( LDT, * ), WORK( * )
                     31: *       ..
                     32: *
                     33: *
                     34: *> \par Purpose:
                     35: *  =============
                     36: *>
                     37: *> \verbatim
                     38: *>
1.3       bertrand   39: *> ZTPMLQT applies a complex orthogonal matrix Q obtained from a
                     40: *> "triangular-pentagonal" complex block reflector H to a general
                     41: *> complex matrix C, which consists of two blocks A and B.
1.1       bertrand   42: *> \endverbatim
                     43: *
                     44: *  Arguments:
                     45: *  ==========
                     46: *
                     47: *> \param[in] SIDE
                     48: *> \verbatim
                     49: *>          SIDE is CHARACTER*1
1.3       bertrand   50: *>          = 'L': apply Q or Q**H from the Left;
                     51: *>          = 'R': apply Q or Q**H from the Right.
1.1       bertrand   52: *> \endverbatim
                     53: *>
                     54: *> \param[in] TRANS
                     55: *> \verbatim
                     56: *>          TRANS is CHARACTER*1
                     57: *>          = 'N':  No transpose, apply Q;
1.3       bertrand   58: *>          = 'C':  Transpose, apply Q**H.
1.1       bertrand   59: *> \endverbatim
                     60: *>
                     61: *> \param[in] M
                     62: *> \verbatim
                     63: *>          M is INTEGER
                     64: *>          The number of rows of the matrix B. M >= 0.
                     65: *> \endverbatim
                     66: *>
                     67: *> \param[in] N
                     68: *> \verbatim
                     69: *>          N is INTEGER
                     70: *>          The number of columns of the matrix B. N >= 0.
                     71: *> \endverbatim
                     72: *>
                     73: *> \param[in] K
                     74: *> \verbatim
                     75: *>          K is INTEGER
                     76: *>          The number of elementary reflectors whose product defines
                     77: *>          the matrix Q.
                     78: *> \endverbatim
                     79: *>
                     80: *> \param[in] L
                     81: *> \verbatim
                     82: *>          L is INTEGER
                     83: *>          The order of the trapezoidal part of V.
                     84: *>          K >= L >= 0.  See Further Details.
                     85: *> \endverbatim
                     86: *>
                     87: *> \param[in] MB
                     88: *> \verbatim
                     89: *>          MB is INTEGER
                     90: *>          The block size used for the storage of T.  K >= MB >= 1.
                     91: *>          This must be the same value of MB used to generate T
                     92: *>          in DTPLQT.
                     93: *> \endverbatim
                     94: *>
                     95: *> \param[in] V
                     96: *> \verbatim
                     97: *>          V is COMPLEX*16 array, dimension (LDA,K)
                     98: *>          The i-th row must contain the vector which defines the
                     99: *>          elementary reflector H(i), for i = 1,2,...,k, as returned by
                    100: *>          DTPLQT in B.  See Further Details.
                    101: *> \endverbatim
                    102: *>
                    103: *> \param[in] LDV
                    104: *> \verbatim
                    105: *>          LDV is INTEGER
                    106: *>          The leading dimension of the array V.
                    107: *>          If SIDE = 'L', LDV >= max(1,M);
                    108: *>          if SIDE = 'R', LDV >= max(1,N).
                    109: *> \endverbatim
                    110: *>
                    111: *> \param[in] T
                    112: *> \verbatim
                    113: *>          T is COMPLEX*16 array, dimension (LDT,K)
                    114: *>          The upper triangular factors of the block reflectors
                    115: *>          as returned by DTPLQT, stored as a MB-by-K matrix.
                    116: *> \endverbatim
                    117: *>
                    118: *> \param[in] LDT
                    119: *> \verbatim
                    120: *>          LDT is INTEGER
                    121: *>          The leading dimension of the array T.  LDT >= MB.
                    122: *> \endverbatim
                    123: *>
                    124: *> \param[in,out] A
                    125: *> \verbatim
                    126: *>          A is COMPLEX*16 array, dimension
                    127: *>          (LDA,N) if SIDE = 'L' or
                    128: *>          (LDA,K) if SIDE = 'R'
                    129: *>          On entry, the K-by-N or M-by-K matrix A.
                    130: *>          On exit, A is overwritten by the corresponding block of
1.3       bertrand  131: *>          Q*C or Q**H*C or C*Q or C*Q**H.  See Further Details.
1.1       bertrand  132: *> \endverbatim
                    133: *>
                    134: *> \param[in] LDA
                    135: *> \verbatim
                    136: *>          LDA is INTEGER
                    137: *>          The leading dimension of the array A.
                    138: *>          If SIDE = 'L', LDC >= max(1,K);
                    139: *>          If SIDE = 'R', LDC >= max(1,M).
                    140: *> \endverbatim
                    141: *>
                    142: *> \param[in,out] B
                    143: *> \verbatim
                    144: *>          B is COMPLEX*16 array, dimension (LDB,N)
                    145: *>          On entry, the M-by-N matrix B.
                    146: *>          On exit, B is overwritten by the corresponding block of
1.3       bertrand  147: *>          Q*C or Q**H*C or C*Q or C*Q**H.  See Further Details.
1.1       bertrand  148: *> \endverbatim
                    149: *>
                    150: *> \param[in] LDB
                    151: *> \verbatim
                    152: *>          LDB is INTEGER
                    153: *>          The leading dimension of the array B.
                    154: *>          LDB >= max(1,M).
                    155: *> \endverbatim
                    156: *>
                    157: *> \param[out] WORK
                    158: *> \verbatim
                    159: *>          WORK is COMPLEX*16 array. The dimension of WORK is
                    160: *>           N*MB if SIDE = 'L', or  M*MB if SIDE = 'R'.
                    161: *> \endverbatim
                    162: *>
                    163: *> \param[out] INFO
                    164: *> \verbatim
                    165: *>          INFO is INTEGER
                    166: *>          = 0:  successful exit
                    167: *>          < 0:  if INFO = -i, the i-th argument had an illegal value
                    168: *> \endverbatim
                    169: *
                    170: *  Authors:
                    171: *  ========
                    172: *
                    173: *> \author Univ. of Tennessee
                    174: *> \author Univ. of California Berkeley
                    175: *> \author Univ. of Colorado Denver
                    176: *> \author NAG Ltd.
                    177: *
1.3       bertrand  178: *> \date June 2017
1.1       bertrand  179: *
                    180: *> \ingroup doubleOTHERcomputational
                    181: *
                    182: *> \par Further Details:
                    183: *  =====================
                    184: *>
                    185: *> \verbatim
                    186: *>
                    187: *>  The columns of the pentagonal matrix V contain the elementary reflectors
                    188: *>  H(1), H(2), ..., H(K); V is composed of a rectangular block V1 and a
                    189: *>  trapezoidal block V2:
                    190: *>
                    191: *>        V = [V1] [V2].
                    192: *>
                    193: *>
                    194: *>  The size of the trapezoidal block V2 is determined by the parameter L,
                    195: *>  where 0 <= L <= K; V2 is lower trapezoidal, consisting of the first L
                    196: *>  rows of a K-by-K upper triangular matrix.  If L=K, V2 is lower triangular;
                    197: *>  if L=0, there is no trapezoidal block, hence V = V1 is rectangular.
                    198: *>
                    199: *>  If SIDE = 'L':  C = [A]  where A is K-by-N,  B is M-by-N and V is K-by-M.
                    200: *>                      [B]
                    201: *>
                    202: *>  If SIDE = 'R':  C = [A B]  where A is M-by-K, B is M-by-N and V is K-by-N.
                    203: *>
                    204: *>  The real orthogonal matrix Q is formed from V and T.
                    205: *>
                    206: *>  If TRANS='N' and SIDE='L', C is on exit replaced with Q * C.
                    207: *>
1.3       bertrand  208: *>  If TRANS='C' and SIDE='L', C is on exit replaced with Q**H * C.
1.1       bertrand  209: *>
                    210: *>  If TRANS='N' and SIDE='R', C is on exit replaced with C * Q.
                    211: *>
1.3       bertrand  212: *>  If TRANS='C' and SIDE='R', C is on exit replaced with C * Q**H.
1.1       bertrand  213: *> \endverbatim
                    214: *>
                    215: *  =====================================================================
                    216:       SUBROUTINE ZTPMLQT( SIDE, TRANS, M, N, K, L, MB, V, LDV, T, LDT,
                    217:      $                    A, LDA, B, LDB, WORK, INFO )
                    218: *
1.3       bertrand  219: *  -- LAPACK computational routine (version 3.7.1) --
1.1       bertrand  220: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                    221: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.3       bertrand  222: *     June 2017
1.1       bertrand  223: *
                    224: *     .. Scalar Arguments ..
                    225:       CHARACTER SIDE, TRANS
                    226:       INTEGER   INFO, K, LDV, LDA, LDB, M, N, L, MB, LDT
                    227: *     ..
                    228: *     .. Array Arguments ..
                    229:       COMPLEX*16         V( LDV, * ), A( LDA, * ), B( LDB, * ),
                    230:      $                   T( LDT, * ), WORK( * )
                    231: *     ..
                    232: *
                    233: *  =====================================================================
                    234: *
                    235: *     ..
                    236: *     .. Local Scalars ..
                    237:       LOGICAL            LEFT, RIGHT, TRAN, NOTRAN
                    238:       INTEGER            I, IB, NB, LB, KF, LDAQ
                    239: *     ..
                    240: *     .. External Functions ..
                    241:       LOGICAL            LSAME
                    242:       EXTERNAL           LSAME
                    243: *     ..
                    244: *     .. External Subroutines ..
                    245:       EXTERNAL           XERBLA, ZTPRFB
                    246: *     ..
                    247: *     .. Intrinsic Functions ..
                    248:       INTRINSIC          MAX, MIN
                    249: *     ..
                    250: *     .. Executable Statements ..
                    251: *
                    252: *     .. Test the input arguments ..
                    253: *
                    254:       INFO   = 0
                    255:       LEFT   = LSAME( SIDE,  'L' )
                    256:       RIGHT  = LSAME( SIDE,  'R' )
                    257:       TRAN   = LSAME( TRANS, 'C' )
                    258:       NOTRAN = LSAME( TRANS, 'N' )
                    259: *
                    260:       IF ( LEFT ) THEN
                    261:          LDAQ = MAX( 1, K )
                    262:       ELSE IF ( RIGHT ) THEN
                    263:          LDAQ = MAX( 1, M )
                    264:       END IF
                    265:       IF( .NOT.LEFT .AND. .NOT.RIGHT ) THEN
                    266:          INFO = -1
                    267:       ELSE IF( .NOT.TRAN .AND. .NOT.NOTRAN ) THEN
                    268:          INFO = -2
                    269:       ELSE IF( M.LT.0 ) THEN
                    270:          INFO = -3
                    271:       ELSE IF( N.LT.0 ) THEN
                    272:          INFO = -4
                    273:       ELSE IF( K.LT.0 ) THEN
                    274:          INFO = -5
                    275:       ELSE IF( L.LT.0 .OR. L.GT.K ) THEN
                    276:          INFO = -6
                    277:       ELSE IF( MB.LT.1 .OR. (MB.GT.K .AND. K.GT.0) ) THEN
                    278:          INFO = -7
                    279:       ELSE IF( LDV.LT.K ) THEN
                    280:          INFO = -9
                    281:       ELSE IF( LDT.LT.MB ) THEN
                    282:          INFO = -11
                    283:       ELSE IF( LDA.LT.LDAQ ) THEN
                    284:          INFO = -13
                    285:       ELSE IF( LDB.LT.MAX( 1, M ) ) THEN
                    286:          INFO = -15
                    287:       END IF
                    288: *
                    289:       IF( INFO.NE.0 ) THEN
                    290:          CALL XERBLA( 'ZTPMLQT', -INFO )
                    291:          RETURN
                    292:       END IF
                    293: *
                    294: *     .. Quick return if possible ..
                    295: *
                    296:       IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 ) RETURN
                    297: *
                    298:       IF( LEFT .AND. NOTRAN ) THEN
                    299: *
                    300:          DO I = 1, K, MB
                    301:             IB = MIN( MB, K-I+1 )
                    302:             NB = MIN( M-L+I+IB-1, M )
                    303:             IF( I.GE.L ) THEN
                    304:                LB = 0
                    305:             ELSE
                    306:                LB = 0
                    307:             END IF
                    308:             CALL ZTPRFB( 'L', 'C', 'F', 'R', NB, N, IB, LB,
                    309:      $                   V( I, 1 ), LDV, T( 1, I ), LDT,
                    310:      $                   A( I, 1 ), LDA, B, LDB, WORK, IB )
                    311:          END DO
                    312: *
                    313:       ELSE IF( RIGHT .AND. TRAN ) THEN
                    314: *
                    315:          DO I = 1, K, MB
                    316:             IB = MIN( MB, K-I+1 )
                    317:             NB = MIN( N-L+I+IB-1, N )
                    318:             IF( I.GE.L ) THEN
                    319:                LB = 0
                    320:             ELSE
                    321:                LB = NB-N+L-I+1
                    322:             END IF
                    323:             CALL ZTPRFB( 'R', 'N', 'F', 'R', M, NB, IB, LB,
                    324:      $                   V( I, 1 ), LDV, T( 1, I ), LDT,
                    325:      $                   A( 1, I ), LDA, B, LDB, WORK, M )
                    326:          END DO
                    327: *
                    328:       ELSE IF( LEFT .AND. TRAN ) THEN
                    329: *
                    330:          KF = ((K-1)/MB)*MB+1
                    331:          DO I = KF, 1, -MB
                    332:             IB = MIN( MB, K-I+1 )
                    333:             NB = MIN( M-L+I+IB-1, M )
                    334:             IF( I.GE.L ) THEN
                    335:                LB = 0
                    336:             ELSE
                    337:                LB = 0
                    338:             END IF
                    339:             CALL ZTPRFB( 'L', 'N', 'F', 'R', NB, N, IB, LB,
                    340:      $                   V( I, 1 ), LDV, T( 1, I ), LDT,
                    341:      $                   A( I, 1 ), LDA, B, LDB, WORK, IB )
                    342:          END DO
                    343: *
                    344:       ELSE IF( RIGHT .AND. NOTRAN ) THEN
                    345: *
                    346:          KF = ((K-1)/MB)*MB+1
                    347:          DO I = KF, 1, -MB
                    348:             IB = MIN( MB, K-I+1 )
                    349:             NB = MIN( N-L+I+IB-1, N )
                    350:             IF( I.GE.L ) THEN
                    351:                LB = 0
                    352:             ELSE
                    353:                LB = NB-N+L-I+1
                    354:             END IF
                    355:             CALL ZTPRFB( 'R', 'C', 'F', 'R', M, NB, IB, LB,
                    356:      $                   V( I, 1 ), LDV, T( 1, I ), LDT,
                    357:      $                   A( 1, I ), LDA, B, LDB, WORK, M )
                    358:          END DO
                    359: *
                    360:       END IF
                    361: *
                    362:       RETURN
                    363: *
                    364: *     End of ZTPMLQT
                    365: *
                    366:       END

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