cungl2(3)

NAME

CUNGL2 - generate an m-by-n complex matrix Q with or

thonormal rows,

SYNOPSIS

SUBROUTINE CUNGL2( M, N, K, A, LDA, TAU, WORK, INFO )
    INTEGER        INFO, K, LDA, M, N
    COMPLEX        A( LDA, * ), TAU( * ), WORK( * )

PURPOSE

CUNGL2 generates an m-by-n complex matrix Q with orthonor

mal rows, which is defined as the first m rows of a product of k

elementary reflectors of order n

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

as returned by CGELQF.

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 i-th row must contain the vector

which defines the elementary reflector H(i), for i = 1,2,...,k,

as returned by CGELQF in the first 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 ele

mentary reflector H(i), as returned by CGELQF.

WORK (workspace) COMPLEX array, dimension (M)

INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = -i, the i-th argument has an ille

gal value

LAPACK version 3.0 15 June 2000

CUNGL2(3)