Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

Contents

?sytri2x

Computes the inverse of a symmetric indefinite matrix after
?sytri2
allocates memory
.

Syntax

lapack_int
LAPACKE_ssytri2x
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
float
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
,
lapack_int
nb
);
lapack_int
LAPACKE_dsytri2x
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
double
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
,
lapack_int
nb
);
lapack_int
LAPACKE_csytri2x
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_float
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
,
lapack_int
nb
);
lapack_int
LAPACKE_zsytri2x
(
int
matrix_layout
,
char
uplo
,
lapack_int
n
,
lapack_complex_double
*
a
,
lapack_int
lda
,
const
lapack_int
*
ipiv
,
lapack_int
nb
);
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
?sytri2x
 actually computes the inverse after the
?sytri2
 routine
allocates memory
 before calling
?sytri2x
.
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
nb
 (block size) diagonal matrix
D
 and the multipliers used to obtain the factor
U
 or
L
 as returned by
?sytrf
. The second dimension of
a
 must be at least
max(1,
n
)
.
lda
The leading dimension of
a
;
lda
≥
 max(1,
n
)
.
ipiv
Array, size at least
max(1,
n
)
.
Details of the interchanges and the
nb
 structure of
D
 as returned by
?sytrf
.
nb
Block size.
Output Parameters
a
If
info
 = 0
, the symmetric inverse of the original matrix.
If
info
 =
'U'
, the upper triangular part of the inverse is formed and the part of
A
 below the diagonal is not referenced.
If
info
 =
'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
, parameter
i
 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.