zungr2.f (3) Linux Manual 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

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