cgeqpf.f(3)

NAME
cgeqpf.f -

SYNOPSIS

  Functions/Subroutines

subroutine cgeqpf (M, N, A, LDA, JPVT, TAU, WORK, RWORK, INFO)
CGEQPF

Function/Subroutine Documentation

  subroutine cgeqpf (integerM, integerN, complex, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, complex, dimension( * )TAU, complex, dimension( * )WORK, real, dimension( * )RWORK, integerINFO)

CGEQPF

Purpose:

     This routine is deprecated and has been replaced by routine CGEQP3.

     CGEQPF computes a QR factorization with column pivoting of a
     complex 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 COMPLEX 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 unitary 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 COMPLEX array, dimension (min(M,N))
              The scalar factors of the elementary reflectors.

    WORK

              WORK is COMPLEX array, dimension (N)

    RWORK

              RWORK is REAL array, dimension (2*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.

Date:
    November 2011

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**H

      where tau is a complex scalar, and v is a complex 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 149 of file cgeqpf.f.

Author

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