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version 1.4, 2010/08/06 15:32:51 version 1.9, 2011/11/21 20:43:23
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   *> \brief \b ZTZRZF
   *
   *  =========== DOCUMENTATION ===========
   *
   * Online html documentation available at 
   *            http://www.netlib.org/lapack/explore-html/ 
   *
   *> \htmlonly
   *> Download ZTZRZF + dependencies 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ztzrzf.f"> 
   *> [TGZ]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ztzrzf.f"> 
   *> [ZIP]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ztzrzf.f"> 
   *> [TXT]</a>
   *> \endhtmlonly 
   *
   *  Definition:
   *  ===========
   *
   *       SUBROUTINE ZTZRZF( M, N, A, LDA, TAU, WORK, LWORK, INFO )
   * 
   *       .. Scalar Arguments ..
   *       INTEGER            INFO, LDA, LWORK, M, N
   *       ..
   *       .. Array Arguments ..
   *       COMPLEX*16         A( LDA, * ), TAU( * ), WORK( * )
   *       ..
   *  
   *
   *> \par Purpose:
   *  =============
   *>
   *> \verbatim
   *>
   *> ZTZRZF reduces the M-by-N ( M<=N ) complex upper trapezoidal matrix A
   *> to upper triangular form by means of unitary transformations.
   *>
   *> The upper trapezoidal matrix A is factored as
   *>
   *>    A = ( R  0 ) * Z,
   *>
   *> where Z is an N-by-N unitary matrix and R is an M-by-M upper
   *> triangular matrix.
   *> \endverbatim
   *
   *  Arguments:
   *  ==========
   *
   *> \param[in] M
   *> \verbatim
   *>          M is INTEGER
   *>          The number of rows of the matrix A.  M >= 0.
   *> \endverbatim
   *>
   *> \param[in] N
   *> \verbatim
   *>          N is INTEGER
   *>          The number of columns of the matrix A.  N >= M.
   *> \endverbatim
   *>
   *> \param[in,out] A
   *> \verbatim
   *>          A is COMPLEX*16 array, dimension (LDA,N)
   *>          On entry, the leading M-by-N upper trapezoidal part of the
   *>          array A must contain the matrix to be factorized.
   *>          On exit, the leading M-by-M upper triangular part of A
   *>          contains the upper triangular matrix R, and elements M+1 to
   *>          N of the first M rows of A, with the array TAU, represent the
   *>          unitary matrix Z as a product of M elementary reflectors.
   *> \endverbatim
   *>
   *> \param[in] LDA
   *> \verbatim
   *>          LDA is INTEGER
   *>          The leading dimension of the array A.  LDA >= max(1,M).
   *> \endverbatim
   *>
   *> \param[out] TAU
   *> \verbatim
   *>          TAU is COMPLEX*16 array, dimension (M)
   *>          The scalar factors of the elementary reflectors.
   *> \endverbatim
   *>
   *> \param[out] WORK
   *> \verbatim
   *>          WORK is COMPLEX*16 array, dimension (MAX(1,LWORK))
   *>          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
   *> \endverbatim
   *>
   *> \param[in] LWORK
   *> \verbatim
   *>          LWORK is INTEGER
   *>          The dimension of the array WORK.  LWORK >= max(1,M).
   *>          For optimum performance LWORK >= M*NB, where NB is
   *>          the optimal blocksize.
   *>
   *>          If LWORK = -1, then a workspace query is assumed; the routine
   *>          only calculates the optimal size of the WORK array, returns
   *>          this value as the first entry of the WORK array, and no error
   *>          message related to LWORK is issued by XERBLA.
   *> \endverbatim
   *>
   *> \param[out] INFO
   *> \verbatim
   *>          INFO is INTEGER
   *>          = 0:  successful exit
   *>          < 0:  if INFO = -i, the i-th argument had an illegal value
   *> \endverbatim
   *
   *  Authors:
   *  ========
   *
   *> \author Univ. of Tennessee 
   *> \author Univ. of California Berkeley 
   *> \author Univ. of Colorado Denver 
   *> \author NAG Ltd. 
   *
   *> \date November 2011
   *
   *> \ingroup complex16OTHERcomputational
   *
   *> \par Contributors:
   *  ==================
   *>
   *>    A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
   *
   *> \par Further Details:
   *  =====================
   *>
   *> \verbatim
   *>
   *>  The factorization is obtained by Householder's method.  The kth
   *>  transformation matrix, Z( k ), which is used to introduce zeros into
   *>  the ( m - k + 1 )th row of A, is given in the form
   *>
   *>     Z( k ) = ( I     0   ),
   *>              ( 0  T( k ) )
   *>
   *>  where
   *>
   *>     T( k ) = I - tau*u( k )*u( k )**H,   u( k ) = (   1    ),
   *>                                                 (   0    )
   *>                                                 ( z( k ) )
   *>
   *>  tau is a scalar and z( k ) is an ( n - m ) element vector.
   *>  tau and z( k ) are chosen to annihilate the elements of the kth row
   *>  of X.
   *>
   *>  The scalar tau is returned in the kth element of TAU and the vector
   *>  u( k ) in the kth row of A, such that the elements of z( k ) are
   *>  in  a( k, m + 1 ), ..., a( k, n ). The elements of R are returned in
   *>  the upper triangular part of A.
   *>
   *>  Z is given by
   *>
   *>     Z =  Z( 1 ) * Z( 2 ) * ... * Z( m ).
   *> \endverbatim
   *>
   *  =====================================================================
       SUBROUTINE ZTZRZF( M, N, A, LDA, TAU, WORK, LWORK, INFO )        SUBROUTINE ZTZRZF( M, N, A, LDA, TAU, WORK, LWORK, INFO )
 *  *
 *  -- LAPACK routine (version 3.2) --  *  -- LAPACK computational routine (version 3.4.0) --
 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --  *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--  *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
 *     November 2006  *     November 2011
 *  *
 *     .. Scalar Arguments ..  *     .. Scalar Arguments ..
       INTEGER            INFO, LDA, LWORK, M, N        INTEGER            INFO, LDA, LWORK, M, N
Line 12 Line 172
       COMPLEX*16         A( LDA, * ), TAU( * ), WORK( * )        COMPLEX*16         A( LDA, * ), TAU( * ), WORK( * )
 *     ..  *     ..
 *  *
 *  Purpose  
 *  =======  
 *  
 *  ZTZRZF reduces the M-by-N ( M<=N ) complex upper trapezoidal matrix A  
 *  to upper triangular form by means of unitary transformations.  
 *  
 *  The upper trapezoidal matrix A is factored as  
 *  
 *     A = ( R  0 ) * Z,  
 *  
 *  where Z is an N-by-N unitary matrix and R is an M-by-M upper  
 *  triangular matrix.  
 *  
 *  Arguments  
 *  =========  
 *  
 *  M       (input) INTEGER  
 *          The number of rows of the matrix A.  M >= 0.  
 *  
 *  N       (input) INTEGER  
 *          The number of columns of the matrix A.  N >= M.  
 *  
 *  A       (input/output) COMPLEX*16 array, dimension (LDA,N)  
 *          On entry, the leading M-by-N upper trapezoidal part of the  
 *          array A must contain the matrix to be factorized.  
 *          On exit, the leading M-by-M upper triangular part of A  
 *          contains the upper triangular matrix R, and elements M+1 to  
 *          N of the first M rows of A, with the array TAU, represent the  
 *          unitary matrix Z as a product of M elementary reflectors.  
 *  
 *  LDA     (input) INTEGER  
 *          The leading dimension of the array A.  LDA >= max(1,M).  
 *  
 *  TAU     (output) COMPLEX*16 array, dimension (M)  
 *          The scalar factors of the elementary reflectors.  
 *  
 *  WORK    (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK))  
 *          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.  
 *  
 *  LWORK   (input) INTEGER  
 *          The dimension of the array WORK.  LWORK >= max(1,M).  
 *          For optimum performance LWORK >= M*NB, where NB is  
 *          the optimal blocksize.  
 *  
 *          If LWORK = -1, then a workspace query is assumed; the routine  
 *          only calculates the optimal size of the WORK array, returns  
 *          this value as the first entry of the WORK array, and no error  
 *          message related to LWORK is issued by XERBLA.  
 *  
 *  INFO    (output) INTEGER  
 *          = 0:  successful exit  
 *          < 0:  if INFO = -i, the i-th argument had an illegal value  
 *  
 *  Further Details  
 *  ===============  
 *  
 *  Based on contributions by  
 *    A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA  
 *  
 *  The factorization is obtained by Householder's method.  The kth  
 *  transformation matrix, Z( k ), which is used to introduce zeros into  
 *  the ( m - k + 1 )th row of A, is given in the form  
 *  
 *     Z( k ) = ( I     0   ),  
 *              ( 0  T( k ) )  
 *  
 *  where  
 *  
 *     T( k ) = I - tau*u( k )*u( k )',   u( k ) = (   1    ),  
 *                                                 (   0    )  
 *                                                 ( z( k ) )  
 *  
 *  tau is a scalar and z( k ) is an ( n - m ) element vector.  
 *  tau and z( k ) are chosen to annihilate the elements of the kth row  
 *  of X.  
 *  
 *  The scalar tau is returned in the kth element of TAU and the vector  
 *  u( k ) in the kth row of A, such that the elements of z( k ) are  
 *  in  a( k, m + 1 ), ..., a( k, n ). The elements of R are returned in  
 *  the upper triangular part of A.  
 *  
 *  Z is given by  
 *  
 *     Z =  Z( 1 ) * Z( 2 ) * ... * Z( m ).  
 *  
 *  =====================================================================  *  =====================================================================
 *  *
 *     .. Parameters ..  *     .. Parameters ..
Line 105 Line 180
 *     ..  *     ..
 *     .. Local Scalars ..  *     .. Local Scalars ..
       LOGICAL            LQUERY        LOGICAL            LQUERY
       INTEGER            I, IB, IWS, KI, KK, LDWORK, LWKOPT, M1, MU, NB,        INTEGER            I, IB, IWS, KI, KK, LDWORK, LWKMIN, LWKOPT,
      $                   NBMIN, NX       $                   M1, MU, NB, NBMIN, NX
 *     ..  *     ..
 *     .. External Subroutines ..  *     .. External Subroutines ..
       EXTERNAL           XERBLA, ZLARZB, ZLARZT, ZLATRZ        EXTERNAL           XERBLA, ZLARZB, ZLARZT, ZLATRZ
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       IF( INFO.EQ.0 ) THEN        IF( INFO.EQ.0 ) THEN
          IF( M.EQ.0 .OR. M.EQ.N ) THEN           IF( M.EQ.0 .OR. M.EQ.N ) THEN
             LWKOPT = 1              LWKOPT = 1
               LWKMIN = 1
          ELSE           ELSE
 *  *
 *           Determine the block size.  *           Determine the block size.
 *  *
             NB = ILAENV( 1, 'ZGERQF', ' ', M, N, -1, -1 )              NB = ILAENV( 1, 'ZGERQF', ' ', M, N, -1, -1 )
             LWKOPT = M*NB              LWKOPT = M*NB
               LWKMIN = MAX( 1, M )
          END IF           END IF
          WORK( 1 ) = LWKOPT           WORK( 1 ) = LWKOPT
 *  *
          IF( LWORK.LT.MAX( 1, M ) .AND. .NOT.LQUERY ) THEN           IF( LWORK.LT.LWKMIN .AND. .NOT.LQUERY ) THEN
             INFO = -7              INFO = -7
          END IF           END IF
       END IF        END IF
Removed from v.1.4  
changed lines
  Added in v.1.9

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