man sorgl2 (Fonctions bibliothèques) - generate an m by n real matrix Q with orthonormal rows,

NAME

SORGL2 - generate an m by n real matrix Q with orthonormal rows,

SYNOPSIS

SUBROUTINE SORGL2(
M, N, K, A, LDA, TAU, WORK, INFO )
INTEGER INFO, K, LDA, M, N
REAL A( LDA, * ), TAU( * ), WORK( * )

PURPOSE

SORGL2 generates an m by n real matrix Q with orthonormal 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 SGELQF.

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 i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by SGELQF 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) REAL array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGELQF.
WORK (workspace) REAL array, dimension (M)
INFO (output) INTEGER
= 0: successful exit

< 0: if INFO = -i, the i-th argument has an illegal value