cung2r(3)

NAME

CUNG2R - generate an m by n complex matrix Q with or

thonormal columns,

SYNOPSIS

SUBROUTINE CUNG2R( M, N, K, A, LDA, TAU, WORK, INFO )
    INTEGER        INFO, K, LDA, M, N
    COMPLEX        A( LDA, * ), TAU( * ), WORK( * )

PURPOSE

CUNG2R generates an m by n complex matrix Q with orthonor

mal 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 CGEQRF.

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 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 CGEQRF in the first k columns of its array argu

ment 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 CGEQRF.

WORK (workspace) COMPLEX array, dimension (N)

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

CUNG2R(3)