SRC/cgelqt.f(3)            Library Functions Manual            SRC/cgelqt.f(3)

NAME
       SRC/cgelqt.f

SYNOPSIS
   Functions/Subroutines
       subroutine cgelqt (m, n, mb, a, lda, t, ldt, work, info)
           CGELQT

Function/Subroutine Documentation
   subroutine cgelqt (integer m, integer n, integer mb, complex, dimension(
       lda, * ) a, integer lda, complex, dimension( ldt, * ) t, integer ldt,
       complex, dimension( * ) work, integer info)
       CGELQT

       Purpose:


            CGELQT computes a blocked LQ factorization of a complex M-by-N matrix A
            using the compact WY representation of Q.

       Parameters
           M

                     M is INTEGER
                     The number of rows of the matrix A.  M >= 0.

           N

                     N is INTEGER
                     The number of columns of the matrix A.  N >= 0.

           MB

                     MB is INTEGER
                     The block size to be used in the blocked QR.  MIN(M,N) >= MB >= 1.

           A

                     A is COMPLEX array, dimension (LDA,N)
                     On entry, the M-by-N matrix A.
                     On exit, the elements on and below the diagonal of the array
                     contain the M-by-MIN(M,N) lower trapezoidal matrix L (L is
                     lower triangular if M <= N); the elements above the diagonal
                     are the rows of V.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,M).

           T

                     T is COMPLEX array, dimension (LDT,MIN(M,N))
                     The upper triangular block reflectors stored in compact form
                     as a sequence of upper triangular blocks.  See below
                     for further details.

           LDT

                     LDT is INTEGER
                     The leading dimension of the array T.  LDT >= MB.

           WORK

                     WORK is COMPLEX array, dimension (MB*N)

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument had an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Further Details:


             The matrix V stores the elementary reflectors H(i) in the i-th row
             above the diagonal. For example, if M=5 and N=3, the matrix V is

                          V = (  1  v1 v1 v1 v1 )
                              (     1  v2 v2 v2 )
                              (         1 v3 v3 )


             where the vi's represent the vectors which define H(i), which are returned
             in the matrix A.  The 1's along the diagonal of V are not stored in A.
             Let K=MIN(M,N).  The number of blocks is B = ceiling(K/MB), where each
             block is of order MB except for the last block, which is of order
             IB = K - (B-1)*MB.  For each of the B blocks, a upper triangular block
             reflector factor is computed: T1, T2, ..., TB.  The MB-by-MB (and IB-by-IB
             for the last block) T's are stored in the MB-by-K matrix T as

                          T = (T1 T2 ... TB).

       Definition at line 123 of file cgelqt.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/cgelqt.f(3)