cgeqpf.f(3) LAPACK cgeqpf.f(3)NAME
cgeqpf.f -
SYNOPSIS
Functions/Subroutines
subroutine cgeqpf (M, N, A, LDA, JPVT, TAU, WORK, RWORK, INFO)
CGEQPFFunction/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This routine is deprecated and has been replaced by routine CGEQP3.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
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 cgeqpf.f(3)
