dorglq.f3
Usage
Functions/Subroutines
subroutine dorglq (m, n, k, a, lda, tau, work, lwork, info)
DORGLQ
Function/Subroutine Documentation
subroutine dorglq (integer m, integer n, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer lwork, integer info)
DORGLQ
Purpose:
!> !> DORGLQ 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 DGELQF. !>
Parameters
M
!> M is INTEGER !> The number of rows of the matrix Q. M >= 0. !>
N
!> N is INTEGER !> The number of columns of the matrix Q. N >= M. !>
K
!> K is INTEGER !> The number of elementary reflectors whose product defines the !> matrix Q. M >= K >= 0. !>
A
!> A is DOUBLE PRECISION 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 DGELQF in the first k rows of its array argument A. !> On exit, the M-by-N matrix Q. !>
LDA
!> LDA is INTEGER !> The first dimension of the array A. LDA >= max(1,M). !>
TAU
!> TAU is DOUBLE PRECISION array, dimension (K) !> TAU(i) must contain the scalar factor of the elementary !> reflector H(i), as returned by DGELQF. !>
WORK
!> WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
!> On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
!>
LWORK
!> LWORK is INTEGER !> The dimension of the array WORK. LWORK >= max(1,M). !> For optimum performance LWORK >= M*NB, where NB is !> the optimal blocksize. !> !> If LWORK = -1, then a workspace query is assumed; the routine !> only calculates the optimal size of the WORK array, returns !> this value as the first entry of the WORK array, and no error !> message related to LWORK is issued by XERBLA. !>
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.
Definition at line 126 of file dorglq.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.