Developer Reference

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

?ormtr

Multiplies a real matrix by the real orthogonal matrix
Q
determined by
?sytrd
.

Syntax

call sormtr
(
side
,
uplo
,
trans
,
m
,
n
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call dormtr
(
side
,
uplo
,
trans
,
m
,
n
,
a
,
lda
,
tau
,
c
,
ldc
,
work
,
lwork
,
info
)
call ormtr
(
a
,
tau
,
c
[
,
side
]
[
,
uplo
]
[
,
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
formed by when reducing a real symmetric matrix
A
to tridiagonal form:
A
=
Q*T*Q
T
. Use this routine after a call to
?sytrd
.
Depending on the parameters
side
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
In the descriptions below,
r
denotes the order of
Q
:
If
side
=
'L'
,
r
=
m
; if
side
=
'R'
,
r
=
n
.
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.
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Use the same
uplo
as supplied to
?syt