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zgeqpf.f -

# SYNOPSIS

## Functions/Subroutines

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

ZGEQPF

# Function/Subroutine Documentation

## subroutine zgeqpf (integerM, integerN, complex*16, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, complex*16, dimension( * )TAU, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)

ZGEQPF
Purpose:
``` This routine is deprecated and has been replaced by routine ZGEQP3.

ZGEQPF 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*16 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*16 array, dimension (min(M,N))
The scalar factors of the elementary reflectors.
```
WORK
```          WORK is COMPLEX*16 array, dimension (N)
```
RWORK
```          RWORK is DOUBLE PRECISION 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
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 zgeqpf.f.

# Author

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