NAME

zung2r - generate an m by n complex matrix Q with orthonormal columns,

SYNOPSIS

SUBROUTINE ZUNG2R(
M, N, K, A, LDA, TAU, WORK, INFO )

INTEGER INFO, K, LDA, M, N

COMPLEX∗16 A( LDA, ∗ ), TAU( ∗ ), WORK( ∗ )

PURPOSE

ZUNG2R generates an m by n complex matrix Q with orthonormal columns, which is defined as the first n columns of a product of k elementary reflectors of order m
 
      Q  =  H(1) H(2) . . . H(k)
 
as returned by ZGEQRF.
 

ARGUMENTS

M       (input) INTEGER
The number of rows of the matrix Q. M >= 0.

N       (input) INTEGER
The number of columns of the matrix Q. M >= N >= 0.

K       (input) INTEGER
The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.

A       (input/output) COMPLEX∗16 array, dimension (LDA,N)
On entry, the i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by ZGEQRF in the first k columns of its array argument A. On exit, the m by n matrix Q.

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

TAU     (input) COMPLEX∗16 array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZGEQRF.

WORK    (workspace) COMPLEX∗16 array, dimension (N)

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

SunSoft, Inc.  —  Last change: 27 Jun 1995