CGEQPF (3) Linux Manual Page

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 This routine is deprecated and has been replaced by routine CGEQP3.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

Generated automatically by Doxygen for LAPACK from the source code.