Developer Reference

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

?ormqr

Multiplies a real matrix by the orthogonal matrix Q of the QR factorization formed by
?geqrf
or
?geqpf
.

Syntax

call sormqr
(
side
,
trans
,
m
,
n
,
k
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call dormqr
(
side
,
trans
,
m
,
n
,
k
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call ormqr
(
a
,
tau
,
c
[
,
side
]
[
,
trans
]
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine multiplies a real matrix
C
by
Q
or
Q
T
, where
Q
is the orthogonal matrix
Q
of the
QR
factorization formed by the routine
?geqrf
or ?geqpf
.
Depending on the parameters
side
left_right
and
trans
, the routine can form one of the matrix products
Q
*
C
,
Q
T
*
C
,
C
*
Q
, or
C
*
Q
T
(overwriting the result on
C
).
Input Parameters
side
CHARACTER*1
.
Must be either
'L'
or
'R'
.
If
side
='L'
,
Q
or
Q
T
is applied to
C
from the left.
If
side
='R'
,
Q
or
Q
T
is applied to
C
from the right.
trans
CHARACTER*1
.
Must be either
'N'
or
'T'
.
If
trans
='N'
, the routine multiplies
C
by
Q
.
If
trans
='T'
, the routine multiplies
C
by
Q
T
.
m
INTEGER
.
The number of rows in the matrix
C
(
m
0
).
n
INTEGER
.
The number of columns in
C
(
n
0
).
k
INTEGER
.
The number of elementary reflectors whose product defines the matrix
Q
. Constraints:
0
k
m
if
side
='L'
;
0
k
n
if
side
='R'
.
a
,