carta
cgeqpf(3)

cgeqpf3

Part of cgeqpf.f(3).

Usage

Functions/Subroutines

CGEQPF

Function/Subroutine Documentation

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

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 This routine is deprecated and has been replaced by routine CGEQP3.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

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 147 of file cgeqpf.f.

History

  • Arch Linux 2026-11-01: the text shown here
  • Debian 8 (Jessie)
  • Debian 7 (Wheezy)
  • Debian 4.0 (Etch) to Debian 3.1 (Sarge)
  • Debian 3.0 (Woody)
  • Debian 2.2 (Potato) to Debian 2.0 (Hamm)
  • Debian 1.3 (Bo)

Author

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