Developer Reference

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

?unmqr

Multiplies a complex matrix by the unitary matrix Q of the QR factorization formed by
?geqrf
.

Syntax

call cunmqr
(
side
,
trans
,
m
,
n
,
k
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call zunmqr
(
side
,
trans
,
m
,
n
,
k
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call unmqr
(
a
,
tau
,
c
[
,
side
]
[
,
trans
]
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine multiplies a rectangular complex matrix
C
by
Q
or
Q
H
, where
Q
is the unitary matrix
Q
of the
QR
factorization formed by the routines
?geqrf
or geqpf
.
Depending on the parameters
side
and
trans
, the routine can form one of the matrix products
Q*C
,
Q
H
*C
,
C*Q
, or
C*Q
H
(overwriting the result on
C
).
Input Parameters
side
CHARACTER*1
.
Must be either
'L'
or
'R'
.
If
side
=
'L'
,
Q
or
Q
H
is applied to
C
from the left.
If
side
=
'R'
,
Q
or
Q
H
is applied to
C
from the right.
trans
CHARACTER*1
.
Must be either
'N'
or
'C'
.
If
trans
=
'N'
, the routine multiplies
C
by
Q
.
If
trans
=
'C'
, the routine multiplies
C
by
Q
H
.
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
,
c
,
tau
,
work
COMPLEX
for
cgeqrf
DOUBLE COMPLEX
for
zgeqrf
.
Arrays:
a
(