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 elementary 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 vector 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 elementary 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 illegal value

  —  LAPACK version 2.0  —  08 October 1994