DORGLQ (3) Linux Manual Page
dorglq.f –
Synopsis
Functions/Subroutines
subroutine dorglq (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)DORGLQ
Function/Subroutine Documentation
subroutine dorglq (integerM, integerN, integerK, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK, integerLWORK, integerINFO)
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
N
The number of rows of the matrix Q. M >= 0.N is INTEGER
K
The number of columns of the matrix Q. N >= M.K is INTEGER
A
The number of elementary reflectors whose product defines the
matrix Q. M >= K >= 0.A is DOUBLE PRECISION array, dimension (LDA,N)
LDA
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 is INTEGER
TAU
The first dimension of the array A. LDA >= max(1,M).TAU is DOUBLE PRECISION array, dimension (K)
WORK
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by DGELQF.WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
LWORK
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.LWORK is INTEGER
INFO
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 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.
Date:
- November 2011
Definition at line 128 of file dorglq.f.