Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

?sytri2

Computes the inverse of a symmetric indefinite matrix through
allocating memory
and calling
?sytri2x
.

Syntax

lapack_int
LAPACKE_ssytri2
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
);
lapack_int
LAPACKE_dsytri2
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
);
lapack_int
LAPACKE_csytri2
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
);
lapack_int
LAPACKE_zsytri2
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
);
Include Files
  • mkl.h
Description
The routine computes the inverse
inv(
A
)
of a symmetric indefinite matrix
A
using the factorization
A
=
U*D*U
T
or
A
=
L*D*L
T
computed by
?sytrf
.
The
?sytri2
routine
allocates a temporary buffer
before calling
?sytri2x
that actually computes the inverse.
Input Parameters
matrix_layout
Specifies whether matrix storage layout is row major (
LAPACK_ROW_MAJOR
) or column major (
LAPACK_COL_MAJOR
).
uplo
Must be
'U'
or
'L'
.
Indicates how the input matrix
A
has been factored:
If
uplo
=
'U'
, the array
a
stores the factorization
A
=
U*D*U
T
.
If
uplo
=
'L'
, the array
a
stores the factorization
A
=
L*D*L
T
.
n
The order of the matrix
A
;
n
0
.
a
Array
a
(size max(1,
lda
*
n
))
contains the block diagonal matrix
D
and the multipliers used to obtain the factor
U
or
L
as returned by
?sytrf
.
lda
The leading dimension of
a
;
lda
max(1,
n
)
.
ipiv
Array, size at least
max(1,
n
)
.
Details of the interchanges and the block structure of
D
as returned by
?sytrf
.
Output Parameters
a
If
info
= 0
, the symmetric inverse of the original matrix.
If
uplo
=
'U'
, the upper triangular part of the inverse is formed and the part of
A
below the diagonal is not referenced.
If
uplo
=
'L'
, the lower triangular part of the inverse is formed and the part of
A
above the diagonal is not referenced.
Return Values
This function returns a value
info
.
If
info
= 0, the execution is successful.
If
info
=
-i
, the
i-
th parameter had an illegal value.
If
info
=
i
,
D
(
i
,
i
) = 0;
D
is singular and its inversion could not be computed.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.