sorg2l()

subroutine sorg2l	(	integer	m,
		integer	n,
		integer	k,
		real, dimension( lda, * )	a,
		integer	lda,
		real, dimension( * )	tau,
		real, dimension( * )	work,
		integer	info )

SORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).

Download SORG2L + dependencies [TGZ] [ZIP] [TXT]

Purpose:

!>
!> SORG2L generates an m by n real matrix Q with orthonormal columns,
!> which is defined as the last n columns of a product of k elementary
!> reflectors of order m
!>
!>       Q  =  H(k) . . . H(2) H(1)
!>
!> as returned by SGEQLF.
!> 

Parameters

[in]	M	!> M is INTEGER !> The number of rows of the matrix Q. M >= 0. !>
[in]	N	!> N is INTEGER !> The number of columns of the matrix Q. M >= N >= 0. !>
[in]	K	!> K is INTEGER !> The number of elementary reflectors whose product defines the !> matrix Q. N >= K >= 0. !>
[in,out]	A	!> A is REAL array, dimension (LDA,N) !> On entry, the (n-k+i)-th column must contain the vector which !> defines the elementary reflector H(i), for i = 1,2,...,k, as !> returned by SGEQLF in the last k columns of its array !> argument A. !> On exit, the m by n matrix Q. !>
[in]	LDA	!> LDA is INTEGER !> The first dimension of the array A. LDA >= max(1,M). !>
[in]	TAU	!> TAU is REAL array, dimension (K) !> TAU(i) must contain the scalar factor of the elementary !> reflector H(i), as returned by SGEQLF. !>
[out]	WORK	!> WORK is REAL array, dimension (N) !>
[out]	INFO	!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument has an illegal value !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.