NAME

cungr2 - generate an m by n complex matrix Q with orthonormal rows,

SYNOPSIS

SUBROUTINE CUNGR2(
M, N, K, A, LDA, TAU, WORK, INFO )

void cungr2(long int m, long int n, long int k, complex ∗ca,
long int lda, complex ∗tau, long int ∗info)

INTEGER INFO, K, LDA, M, N

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

PURPOSE

CUNGR2 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(2)’ . . . H(k)’
 
as returned by CGERQF.
 

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. N >= M.

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

A       (input/output) COMPLEX 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 CGERQF in the last k rows 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 array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGERQF.

WORK    (workspace) COMPLEX array, dimension (M)

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

Sun, Inc.  —  Last change: 20 Sep 1996