Developer Reference

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

?sycon_rook

Estimates the reciprocal of the condition number of a symmetric matrix.

Syntax

call ssycon_rook
(
uplo
,
n
,
a
,
lda
,
ipiv
,
anorm
,
rcond
,
work
,
iwork
,
info
)
call dsycon_rook
(
uplo
,
n
,
a
,
lda
,
ipiv
,
anorm
,
rcond
,
work
,
iwork
,
info
)
call csycon_rook
(
uplo
,
n
,
a
,
lda
,
ipiv
,
anorm
,
rcond
,
work
,
info
)
call zsycon_rook
(
uplo
,
n
,
a
,
lda
,
ipiv
,
anorm
,
rcond
,
work
,
info
)
call sycon_rook
(
a
,
ipiv
,
anorm
,
rcond
[
,
uplo
]
[
,
info
]
)
Include Files
  • mkl.fi
    ,
    lapack.f90
Description
The routine estimates the reciprocal of the condition number of a symmetric matrix
A
:
κ
1
(
A
) = ||
A
||
1
||
A
-1
||
1
(since
A
is symmetric,
κ
(
A
) =
κ
1
(
A
)
).
Before calling this routine:
  • compute
    anorm
    (either ||
    A
    ||
    1
    = max
    j
    Σ
    i
    |
    a
    i
    j
    | or ||
    A
    ||
    = max
    i
    Σ
    j
    |
    a
    i
    j
    |)
  • call
    ?sytrf_rook
    to compute the factorization of
    A
    .
Input Parameters
uplo
CHARACTER*1
.
Must be
'U'
or
'L'
.
Indicates how the input matrix
A
has been factored:
If
uplo
=
'U'
, the array
a
stores the upper triangular factor
U
of the factorization
A
=
U*D*U
T
.
If
uplo
=
'L'
, the array
a
stores the lower triangular factor
L
of the factorization
A
=
L*D*L
T
.
n
INTEGER
.
The order of matrix
A
;
n
0.
a
,
work
REAL
for
ssycon_rook
DOUBLE PRECISION
for
dsycon_rook
COMPLEX
for
csycon_rook
DOUBLE COMPLEX
for
zsycon_rook
.
Arrays: