sorgr2(3)

NAME

SORGR2 - generate an m by n real matrix Q with orthonormal

rows,

SYNOPSIS

SUBROUTINE SORGR2( M, N, K, A, LDA, TAU, WORK, INFO )
    INTEGER        INFO, K, LDA, M, N
    REAL           A( LDA, * ), TAU( * ), WORK( * )

PURPOSE

SORGR2 generates an m by n real matrix Q with orthonormal

rows, which is defined as the last m rows of a product of k ele

mentary reflectors of order n

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

as returned by SGERQF.

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) REAL array, dimension (LDA,N)

On entry, the (m-k+i)-th row must contain the vec

tor which defines the elementary reflector H(i), for i =

1,2,...,k, as returned by SGERQF 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) REAL array, dimension (K)

TAU(i) must contain the scalar factor of the ele

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

WORK (workspace) REAL 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

SORGR2(3)