Developer Reference

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

?orgrq

Generates the real matrix Q of the RQ factorization formed by
?gerqf
.

Syntax

call sorgrq
(
m
,
n
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
call dorgrq
(
m
,
n
,
k
,
a
,
lda
,
tau
,
work
,
lwork
,
info
)
call orgrq
(
a
,
tau
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine generates an
m
-by-
n
real matrix with orthonormal rows, which is defined as the last
m
rows of a product of
k
elementary reflectors
H
(
i
)
of order
n
:
Q
=
H
(1)*
H
(2)
*...*
H
(
k
)
as returned by the routines gerqf . Use this routine after a call to
sgerqf
/
dgerqf
.
Input Parameters
m
INTEGER
.
The number of rows of the matrix
Q
(
m
0
).
n
INTEGER
.
The number of columns of the matrix
Q
(
n
 
m
).
k
INTEGER
.
The number of elementary reflectors whose product defines the matrix
Q
(
m
 
k
0
).
a
,
tau
,
work
REAL
for
sorgrq
DOUBLE PRECISION
for
dorgrq
Arrays:
a
(
lda
,*)
,
tau
(*)
.
On entry, the (
m
-
k
+
i
)-th row of
a
must contain the vector which defines the elementary reflector
H
(
i
)
, for i = 1,2,...,
k
, as returned by
sgerqf
/
dgerqf
in the last
k
rows of its array argument
a
;
tau
(i)
must contain the scalar factor of the elementary reflector
H
(
i
)
, as returned by
sgerqf
/
dgerqf
;
The second dimension of
a
must be at least max(1,
n
).
The size of
tau
must be at least max(1,
k
).
work
is a workspace array, its dimension
max(1,
lwork
)
.
lda
INTEGER
.
The leading dimension of
a
; at least max(1,
m
).
lwork
INTEGER
.
Th