zungr2.f man page

zungr2.f —

Synopsis

Functions/Subroutines

subroutine zungr2 (M, N, K, A, LDA, TAU, WORK, INFO)
ZUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm).

Function/Subroutine Documentation

subroutine zungr2 (integerM, integerN, integerK, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( * )TAU, complex*16, dimension( * )WORK, integerINFO)

ZUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm).

Purpose:

ZUNGR2 generates an m by n complex matrix Q with orthonormal rows,
which is defined as the last m rows of a product of k elementary
reflectors of order n

      Q  =  H(1)**H H(2)**H . . . H(k)**H

as returned by ZGERQF.

Parameters:

M

M is INTEGER
The number of rows of the matrix Q. M >= 0.

N

N is INTEGER
The number of columns of the matrix Q. N >= M.

K

K is INTEGER
The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.

A

A is COMPLEX*16 array, dimension (LDA,N)
On entry, the (m-k+i)-th row must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by ZGERQF in the last k rows of its array argument
A.
On exit, the m-by-n matrix Q.

LDA

LDA is INTEGER
The first dimension of the array A. LDA >= max(1,M).

TAU

TAU is COMPLEX*16 array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by ZGERQF.

WORK

WORK is COMPLEX*16 array, dimension (M)

INFO

INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument has an illegal value

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 115 of file zungr2.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

zungr2(3) is an alias of zungr2.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK