Developer Reference

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

cblas_?hpr2

Performs a rank-2 update of a Hermitian packed matrix.

Syntax

void
cblas_chpr2
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
n
,
const
void
*alpha
,
const
void
*x
,
const
MKL_INT
incx
,
const
void
*y
,
const
MKL_INT
incy
,
void
*ap
);
void
cblas_zhpr2
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
n
,
const
void
*alpha
,
const
void
*x
,
const
MKL_INT
incx
,
const
void
*y
,
const
MKL_INT
incy
,
void
*ap
);
Include Files
  • mkl.h
Description
The
?hpr2
routines perform a matrix-vector operation defined as
A := alpha*x*conjg(y') + conjg(alpha)*y*conjg(x') + A,
where:
alpha
is a scalar,
x
and
y
are
n
-element vectors,
A
is an
n
-by-
n
Hermitian matrix, supplied in packed form.
Input Parameters
Layout
Specifies whether two-dimensional array storage is row-major (
CblasRowMajor
) or column-major (
CblasColMajor
).
uplo
Specifies whether the upper or lower triangular part of the matrix
A
is supplied in the packed array
ap
.
If
uplo
=
CblasUpper
, then the upper triangular part of the matrix
A
is supplied in the packed array
ap
.
If
uplo
=
CblasLower
, then the low triangular part of the matrix
A
is supplied in the packed array
ap
.
n
Specifies the order of the matrix
A
. The value of
n
must be at least zero.
alpha
Specifies the scalar
alpha
.
x
Array, dimension at least
(1 +(
n
- 1)*abs(
incx
))
. Before entry, the incremented array
x
must contain the
n
-element vector
x
.
incx
Specifies the increment for the elements of
x
.
The value of
incx
must not be zero.
y
Array, size at least
(1 +(
n
- 1)*abs(
incy
))
. Before entry, the incremented array
y
must contain the
n
-element vector
y
.
incy
Specifies the increment for the elements of
y
.
The value of
incy
must not be zero.
ap
Array, size at least
((
n
*(
n
+ 1))/2)
.
For
Layout
=
CblasColMajor
:
Before entry with
uplo
=
CblasUpper
, the array
ap
must contain the upper triangular part of the Hermitian matrix packed sequentially, column-by-column, so that
ap
[0]
contains
A
1, 1
,
ap
[1]
and
ap
[2]
contain
A
1, 2
and
A
2, 2
respectively, and so on.
Before entry with
uplo
=
CblasLower
, the array
ap
must contain the lower triangular part of the Hermitian matrix packed sequentially, column-by-column, so that
ap
[0]
contains
A
1, 1
,
ap
[1]
and
ap
[2]
contain
A
2, 1
and
A
3, 1
respectively, and so on.
For
Layout
=
CblasRowMajor
:
Before entry with
uplo
=
CblasUpper
, the array
ap
must contain the upper triangular part of the Hermitian matrix packed sequentially, row-by-row,
ap
[0]
contains
A
1, 1
,
ap
[1]
and
ap
[2]
contain
A
1, 2
and
A
1, 3
respectively, and so on.
Before entry with
uplo
=
CblasLower
, the array
ap
must contain the lower triangular part of the Hermitian matrix packed sequentially, row-by-row, so that
ap
[0]
contains
A
1, 1
,
ap
[1]
and
ap
[2]
contain
A
2, 1
and
A
2, 2
respectively, and so on.
The imaginary parts of the diagonal elements need not be set and are assumed to be zero.
Output Parameters
ap
With
uplo
=
CblasUpper
, overwritten by the upper triangular part of the updated matrix.
With
uplo
=
CblasLower
, overwritten by the lower triangular part of the updated matrix.
The imaginary parts of the diagonal elements need are set 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