SRC/dgemlqt.f(3)

NAME
SRC/dgemlqt.f

SYNOPSIS

  Functions/Subroutines
subroutine dgemlqt (side, trans, m, n, k, mb, v, ldv, t, ldt, c, ldc, work, info)
DGEMLQT

Function/Subroutine Documentation

  subroutine dgemlqt (character side, character trans, integer m, integer n, integer k, integer mb, double precision, dimension( ldv, * ) v, integer ldv, double precision, dimension( ldt, * ) t, integer ldt, double precision, dimension( ldc, * ) c, integer ldc, double precision, dimension( * ) work, integer info)

DGEMLQT

Purpose:

    !>
    !> DGEMLQT overwrites the general real M-by-N matrix C with
    !>
    !>                 SIDE = 'L'     SIDE = 'R'
    !> TRANS = 'N':      Q C            C Q
    !> TRANS = 'T':   Q**T C            C Q**T
    !>
    !> where Q is a real orthogonal matrix defined as the product of K
    !> elementary reflectors:
    !>
    !>       Q = H(1) H(2) . . . H(K) = I - V T V**T
    !>
    !> generated using the compact WY representation as returned by DGELQT.
    !>
    !> Q is of order M if SIDE = 'L' and of order N  if SIDE = 'R'.
    !>

Parameters
    SIDE

    !>          SIDE is CHARACTER*1
    !>          = 'L': apply Q or Q**T from the Left;
    !>          = 'R': apply Q or Q**T from the Right.
    !>

    TRANS

    !>          TRANS is CHARACTER*1
    !>          = 'N':  No transpose, apply Q;
    !>          = 'C':  Transpose, apply Q**T.
    !>

    M

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

    N

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

    K

    !>          K is INTEGER
    !>          The number of elementary reflectors whose product defines
    !>          the matrix Q.
    !>          If SIDE = 'L', M >= K >= 0;
    !>          if SIDE = 'R', N >= K >= 0.
    !>

    MB

    !>          MB is INTEGER
    !>          The block size used for the storage of T.  K >= MB >= 1.
    !>          This must be the same value of MB used to generate T
    !>          in DGELQT.
    !>

    V

    !>          V is DOUBLE PRECISION array, dimension
    !>                               (LDV,M) if SIDE = 'L',
    !>                               (LDV,N) if SIDE = 'R'
    !>          The i-th row must contain the vector which defines the
    !>          elementary reflector H(i), for i = 1,2,...,k, as returned by
    !>          DGELQT in the first K rows of its array argument A.
    !>

    LDV

    !>          LDV is INTEGER
    !>          The leading dimension of the array V.  LDV >= max(1,K).
    !>

    T

    !>          T is DOUBLE PRECISION array, dimension (LDT,K)
    !>          The upper triangular factors of the block reflectors
    !>          as returned by DGELQT, stored as a MB-by-K matrix.
    !>

    LDT

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

    C

    !>          C is DOUBLE PRECISION array, dimension (LDC,N)
    !>          On entry, the M-by-N matrix C.
    !>          On exit, C is overwritten by Q C, Q**T C, C Q**T or C Q.
    !>

    LDC

    !>          LDC is INTEGER
    !>          The leading dimension of the array C. LDC >= max(1,M).
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array. The dimension of
    !>          WORK is N*MB if SIDE = 'L', or  M*MB if SIDE = 'R'.
    !>

    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.

Definition at line 166 of file dgemlqt.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.