Developer Reference

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

?lasy2

Solves the Sylvester matrix equation where the matrices are of order 1 or 2.

Syntax

call slasy2
(
ltranl
,
ltranr
,
isgn
,
n1
,
n2
,
tl
,
ldtl
,
tr
,
ldtr
,
b
,
ldb
,
scale
,
x
,
ldx
,
xnorm
,
info
)
call dlasy2
(
ltranl
,
ltranr
,
isgn
,
n1
,
n2
,
tl
,
ldtl
,
tr
,
ldtr
,
b
,
ldb
,
scale
,
x
,
ldx
,
xnorm
,
info
)
Include Files
  • mkl.fi
Description
The routine solves for the
n1
-by-
n2
matrix
X
,
1 ≤
n1
,
n2
≤ 2
, in
op(
TL
)*
X
+
isgn
*
X
*op(
TR
) =
scale
*
B
,
where
TL
is
n1
-by-
n1
,
TR
is
n2
-by-
n2
,
B
is
n1
-by-
n2
,
and
isgn
= 1
or -1.
op(
T
) =
T
or
T
T
, where
T
T
denotes the transpose of
T
.
Input Parameters
ltranl
LOGICAL
.
On entry,
ltranl
specifies the
op(
TL
)
:
=
.FALSE.
,
op(
TL
) =
TL
,
=
.TRUE.
,
op(
TL
) = (
TL
)
T
.
ltranr
LOGICAL
.
On entry,
ltranr
specifies the op(
TR
):
=
.FALSE.
,
op(
TR
) =
TR
,
=
.TRUE.
,
op(
TR
) = (
TR
)
T
.
isgn
INTEGER
. On entry,
isgn
specifies the sign of the equation as described before.
isgn
may only be 1 or -1.
n1
INTEGER
. On entry,
n1
specifies the order of matrix
TL
.
n1
may only be 0, 1 or 2.
n2
INTEGER
. On entry,
n2
specifies the order of matrix
TR
.
n2
may only be 0, 1 or 2.
tl
REAL
for
slasy2
DOUBLE PRECISION
for
dlasy2
.
Array,
DIMENSION
(
ldtl
,2).
On entry,
tl
contains an
n1
-by-
n1
matrix
TL
.
ldtl
INTEGER
.The leading dimension of the matrix