Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 0.9
  • 09/09/2020
  • Public Content
Contents

?hbev

Computes all eigenvalues and, optionally, eigenvectors of a Hermitian band matrix.

Syntax

lapack_int LAPACKE_chbev
(
int
matrix_layout
,
char
jobz
,
char
uplo
,
lapack_int
n
,
lapack_int
kd
,
lapack_complex_float*
ab
,
lapack_int
ldab
,
float*
w
,
lapack_complex_float*
z
,
lapack_int
ldz
);
lapack_int LAPACKE_zhbev
(
int
matrix_layout
,
char
jobz
,
char
uplo
,
lapack_int
n
,
lapack_int
kd
,
lapack_complex_double*
ab
,
lapack_int
ldab
,
double*
w
,
lapack_complex_double*
z
,
lapack_int
ldz
);
Include Files
  • mkl.h
Description
The routine computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian band matrix
A
.
Input Parameters
matrix_layout
Specifies whether matrix storage layout is row major (
LAPACK_ROW_MAJOR
) or column major (
LAPACK_COL_MAJOR
).
jobz
Must be
'N'
 or
'V'
.
If
jobz
 =
'N'
, then only eigenvalues are computed.
If
jobz
 =
'V'
, then eigenvalues and eigenvectors are computed.
uplo
Must be
'U'
 or
'L'
.
If
uplo
 =
'U'
,
ab
 stores the upper triangular part of
A
.
If
uplo
 =
'L'
,
ab
 stores the lower triangular part of
A
.
n
The order of the matrix
A
 (
n
≥
 0
).
kd
The number of super- or sub-diagonals in
A
(
kd
≥
 0
).
ab
ab
(size at least max(1,
ldab
*
n
) for column major layout and at least max(1,
ldab
*(
kd
 + 1)) for row major layout)
 is an array containing either upper or lower triangular part of the Hermitian matrix
A
 (as specified by
uplo
) in band storage format.
ldab
The leading dimension of
ab
; must be at least
kd
 +1
for column major layout and
n
 for row major layout
.
ldz
The leading dimension of the output array
z
.
Constraints:
if
jobz
 =
'N'
, then
ldz
≥
 1
;
if
jobz
 =
'V'
, then
ldz
≥
 max(1,
n
) .
Output Parameters
w
Array, size at least max(1,
n
).
If
info
 = 0
, contains the eigenvalues in ascending order.
z
Array
z
(size max(1,
ldz
*
n
)
.
If
jobz
 =
'V'
, then if
info
 = 0
,
z
 contains the orthonormal eigenvectors of the matrix
A
, with the
i
-th column of
z
 holding the eigenvector associated with
w
[
i
 - 1]
.
If
jobz
 =
'N'
, then
z
 is not referenced.
ab
On exit, this array is overwritten by the values generated during the reduction to tridiagonal form(see the description of hbtrd).
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
, then the algorithm failed to converge;
i
 indicates the number of elements of an intermediate tridiagonal form which did not converge to zero.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804