Developer Reference

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

?lags2

Computes 2-by-2 orthogonal matrices U, V, and Q, and applies them to matrices A and B such that the rows of the transformed A and B are parallel.

Syntax

call slags2
(
upper
,
a1
,
a2
,
a3
,
b1
,
b2
,
b3
,
csu
,
snu
,
csv
,
snv
,
csq
,
snq
)
call dlags2
(
upper
,
a1
,
a2
,
a3
,
b1
,
b2
,
b3
,
csu
,
snu
,
csv
,
snv
,
csq
,
snq
)
call clags2
(
upper
,
a1
,
a2
,
a3
,
b1
,
b2
,
b3
,
csu
,
snu
,
csv
,
snv
,
csq
,
snq
)
call zlags2
(
upper
,
a1
,
a2
,
a3
,
b1
,
b2
,
b3
,
csu
,
snu
,
csv
,
snv
,
csq
,
snq
)
Include Files
  • mkl.fi
Description
For real flavors, the routine computes 2-by-2 orthogonal matrices
U
,
V
and
Q
, such that if
upper
=
.TRUE.
, then
Equation
and
Equation
or if
upper
=
.FALSE.
, then
Equation
and
Equation
The rows of the transformed
A
and
B
are parallel, where
Equation
Here
Z
T
denotes the transpose of
Z
.
For complex flavors, the routine computes 2-by-2 unitary matrices
U
,
V
and
Q
, such that if
upper
=
.TRUE.
, then
Equation
and
Equation
or if
upper
=
.FALSE.
, then
Equation
and
Equation
The rows of the transformed
A
and
B
are parallel, where
Equation
Input Parameters
upper
LOGICAL
.
If
upper
=
.TRUE.
, the input matrices
A
and
B
are upper triangular; If
upper
=
.FALSE.
, the input matrices
A
and
B
are lower triangular.
a1
,
a3
REAL
for
slags2
and
clags2
DOUBLE PRECISION
for
dlags2
and
zlags2
a2
REAL
for
slags2
DOUBLE PRECISION
for
dlags2
COMPLEX
for
clags2
COMPLEX*16
for
zlags2
On entry,
a1, a2
and
a3
are elements of the input 2-by-2 upper (lower) triangular matrix
A
.
Output Parameters