Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?orgqr

Generates the real orthogonal matrix Q of the QR factorization formed by
?geqrf
.

Syntax

call sorgqr
(
m
,
n
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
call dorgqr
(
m
,
n
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
call orgqr
(
a
,
tau
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine generates the whole or part of
m
-by-
m
orthogonal matrix
Q
of the
QR
factorization formed by the routine
?geqrf
or geqpf . Use this routine after a call to
sgeqrf
/
dgeqrf
or
sgeqpf
/
dgeqpf
.
Usually
Q
is determined from the
QR
factorization of an
m
by
p
matrix
A
with
m
p
. To compute the whole matrix
Q
, use:
call
?orgqr
(
m
,
m
,
p
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
To compute the leading
p
columns of
Q
(which form an orthonormal basis in the space spanned by the columns of
A
):
call
?orgqr
(
m
,
p
,
p
,
a
,
lda
,
work
,
lwork
,
info
)
To compute the matrix
Q
k
of the
QR
factorization of leading
k
columns of the matrix
A
:
call
?orgqr
(
m
,
m
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
To compute the leading
k
columns of
Q
k
(which form an orthonormal basis in the space spanned by leading
k
columns of the matrix
A
):
call
?orgqr
(
m
,
k
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
Input Parameters
m
INTEGER
.
The order of the orthogonal matrix
Q
(
m
0
).
n
<