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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/DEPRECATED/dgeqpf.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/DEPRECATED/dgeqpf.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/DEPRECATED/dgeqpf.f

SYNOPSIS

Functions/Subroutines


subroutine DGEQPF (m, n, a, lda, jpvt, tau, work, info)
DGEQPF

Function/Subroutine Documentation

subroutine DGEQPF (integer m, integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) jpvt, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer info)

DGEQPF

Purpose:

!>
!> This routine is deprecated and has been replaced by routine DGEQP3.
!>
!> DGEQPF 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 DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (min(M,N))
!>          The scalar factors of the elementary reflectors.
!> 

WORK

!>          WORK is DOUBLE PRECISION 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 dgeqpf.f.

Author

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Version 3.12.0 LAPACK