Developer Reference

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

?laein

Computes a specified right or left eigenvector of an upper Hessenberg matrix by inverse iteration.

Syntax

call slaein
(
rightv
,
noinit
,
n
,
h
,
ldh
,
wr
,
wi
,
vr
,
vi
,
b
,
ldb
,
work
,
eps3
,
smlnum
,
bignum
,
info
)
call dlaein
(
rightv
,
noinit
,
n
,
h
,
ldh
,
wr
,
wi
,
vr
,
vi
,
b
,
ldb
,
work
,
eps3
,
smlnum
,
bignum
,
info
)
call claein
(
rightv
,
noinit
,
n
,
h
,
ldh
,
w
,
v
,
b
,
ldb
,
rwork
,
eps3
,
smlnum
,
info
)
call zlaein
(
rightv
,
noinit
,
n
,
h
,
ldh
,
w
,
v
,
b
,
ldb
,
rwork
,
eps3
,
smlnum
,
info
)
Include Files
  • mkl.fi
Description
The routine
?laein
uses inverse iteration to find a right or left eigenvector corresponding to the eigenvalue (
wr
,
wi
) of a real upper Hessenberg matrix
H
(for real flavors
slaein
/
dlaein
) or to the eigenvalue
w
of a complex upper Hessenberg matrix
H
(for complex flavors
claein
/
zlaein
).
Input Parameters
rightv
LOGICAL
.
If
rightv
=
.TRUE.
, compute right eigenvector;
if
rightv
=
.FALSE.
, compute left eigenvector.
noinit
LOGICAL
.
If
noinit
=
.TRUE.
, no initial vector is supplied in (
vr
,
vi
) or in
v
(for complex flavors);
if
noinit
=
.FALSE.
, initial vector is supplied in (
vr
,
vi
) or in
v
(for complex flavors).
n
INTEGER
. The order of the matrix
H
(
n
0
).
h
REAL
for
slaein
DOUBLE PRECISION
for
dlaein
COMPLEX
for
claein
DOUBLE COMPLEX
for
zlaein
.
Array
h
(
ldh
, *).
The second dimension of
h
must be at least
max(1,
n
)
. Contains the upper Hessenberg matrix
H
.
ldh