SRC/DEPRECATED/sgeqpf.f(3)

NAME
SRC/DEPRECATED/sgeqpf.f

SYNOPSIS

  Functions/Subroutines
subroutine sgeqpf (m, n, a, lda, jpvt, tau, work, info)
SGEQPF

Function/Subroutine Documentation

  subroutine sgeqpf (integer m, integer n, real, dimension( lda, * ) a, integer lda, integer, dimension( * ) jpvt, real, dimension( * ) tau, real, dimension( * ) work, integer info)

SGEQPF

Purpose:

    !>
    !> This routine is deprecated and has been replaced by routine SGEQP3.
    !>
    !> SGEQPF computes a QR factorization with column pivoting of a
    !> real M-by-N matrix A: A*P = Q*R.
    !>

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
    !>

    A

    !>          A is REAL array, dimension (LDA,N)
    !>          On entry, the M-by-N matrix A.
    !>          On exit, the upper triangle of the array contains the
    !>          min(M,N)-by-N upper triangular matrix R; the elements
    !>          below the diagonal, together with the array TAU,
    !>          represent the orthogonal matrix Q as a product of
    !>          min(m,n) elementary reflectors.
    !>

    LDA

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

    JPVT

    !>          JPVT is INTEGER array, dimension (N)
    !>          On entry, if JPVT(i) .ne. 0, the i-th column of A is permuted
    !>          to the front of A*P (a leading column); if JPVT(i) = 0,
    !>          the i-th column of A is a free column.
    !>          On exit, if JPVT(i) = k, then the i-th column of A*P
    !>          was the k-th column of A.
    !>

    TAU

    !>          TAU is REAL array, dimension (min(M,N))
    !>          The scalar factors of the elementary reflectors.
    !>

    WORK

    !>          WORK is REAL array, dimension (3*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 Q is represented as a product of elementary reflectors
    !>
    !>     Q = H(1) H(2) . . . H(n)
    !>
    !>  Each H(i) has the form
    !>
    !>     H = I - tau * v * v**T
    !>
    !>  where tau is a real scalar, and v is a real vector with
    !>  v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i).
    !>
    !>  The matrix P is represented in jpvt as follows: If
    !>     jpvt(j) = i
    !>  then the jth column of P is the ith canonical unit vector.
    !>
    !>  Partial column norm updating strategy modified by
    !>    Z. Drmac and Z. Bujanovic, Dept. of Mathematics,
    !>    University of Zagreb, Croatia.
    !>  -- April 2011                                                      --
    !>  For more details see LAPACK Working Note 176.
    !>

Definition at line 141 of file sgeqpf.f.

Author

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