Developer Reference

Contents

cblas_?her2k

Performs a Hermitian rank-2k update.

Syntax

void
cblas_cher2k
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
CBLAS_TRANSPOSE
trans
,
const
MKL_INT
n
,
const
MKL_INT
k
,
const
void
*alpha
,
const
void
*a
,
const
MKL_INT
lda
,
const
void
*b
,
const
MKL_INT
ldb
,
const
float
beta
,
void
*c
,
const
MKL_INT
ldc
);
void
cblas_zher2k
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
CBLAS_TRANSPOSE
trans
,
const
MKL_INT
n
,
const
MKL_INT
k
,
const
void
*alpha
,
const
void
*a
,
const
MKL_INT
lda
,
const
void
*b
,
const
MKL_INT
ldb
,
const
double
beta
,
void
*c
,
const
MKL_INT
ldc
);
Include Files
  • mkl.h
Description
The
?her2k
routines perform a rank-2k
matrix-matrix operation using general matrices
A
and
B
and a Hermitian matrix
C
.
The operation is defined as
C
:=
alpha
*
A
*
B
H
+ conjg(
alpha
)
B
*
A
H
+
beta
*C
or
C
:=
alpha
*
A
H
*
B
+ conjg(
alpha
)*
B
H
*
A
+
beta
*C
where:
alpha
is a scalar and
beta
is a real scalar.
C
is an
n
-by-
n
Hermitian matrix.
A
and
B
are
n
-by-
k
matrices in the first case and
k
-by-
n
matrices in the second case.
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 array
c
is used.
If
uplo
=
CblasUpper
, then the upper triangular of the array
c
is used.
If
uplo
=
CblasLower
, then the low triangular of the array
c
is used.
trans
Specifies the operation:
if
trans
=
CblasNoTrans
, then
C
:=
alpha
*
A
*
B
H
+
alpha
*
B
*
A
H
+
beta
*
C
;
if
trans
=
CblasConjTrans
, then
C
:=
alpha
*
A
H
*
B
+
alpha
*
B
H
*
A
+
beta
*
C
.
n
Specifies the order of the matrix
C
.
The value of
n
must be at least zero.
k
With
trans
=
CblasNoTrans
specifies the number of columns of the matrix
A
, and with
trans
=
CblasConjTrans
,
k
specifies the number of rows of the matrix
A
.
The value of
k
must be at least equal to zero.
alpha
Specifies the scalar
alpha
.
a
trans
=
CblasNoTrans
trans
=
CblasConjTrans
Layout
=
CblasColMajor
Array, size
lda
*
k
.
Before entry, the leading
n
-by-
k
part of the array
a
must contain the matrix
A
.
Array, size
lda
*
n
.
Before entry, the leading
k
-by-
n
part of the array
a
must contain the matrix
A
.
Layout
=
CblasRowMajor
Array, size
lda
*
n
.
Before entry, the leading
k
-by-
n
part of the array
a
must contain the matrix
A
.
Array, size
lda
*
k
.
Before entry, the leading
n
-by-
k
part of the array
a
must contain the matrix
A
.
lda
Specifies the leading dimension of
a
as declared in the calling (sub)program.
trans
=
CblasNoTrans
trans
=
CblasConjTrans
Layout
=
CblasColMajor
lda
must be at least
max(1,
n
)
.
lda
must be at least
max(1,
k
)
Layout
=
CblasRowMajor
lda
must be at least
max(1,
k
)
lda
must be at least
max(1,
n
)
.
beta
Specifies the scalar
beta
.
b
trans
=
CblasNoTrans
trans
=
CblasConjTrans
Layout
=
CblasColMajor
Array, size
ldb
*
k
.
Before entry, the leading
n
-by-
k
part of the array
b
must contain the matrix
B
.
Array, size
ldb
*
n
.
Before entry, the leading
k
-by-
n
part of the array
b
must contain the matrix
B
.
Layout
=
CblasRowMajor
Array, size
lda
*
n
.
Before entry, the leading
k
-by-
n
part of the array
b
must contain the matrix
B
.
Array, size
lda
*
k
.
Before entry, the leading
n
-by-
k
part of the array
b
must contain the matrix
B
.
ldb
Specifies the leading dimension of
a
as declared in the calling (sub)program.
trans
=
CblasNoTrans
trans
=
CblasConjTrans
Layout
=
CblasColMajor
ldb
must be at least
max(1,
n
)
.
ldb
must be at least
max(1,
k
)
Layout
=
CblasRowMajor
ldb
must be at least
max(1,
k
)
ldb
must be at least
max(1,
n
)
.
c
Array, size
ldc
by
n
.
Before entry with
uplo
=
CblasUpper
, the leading
n
-by-
n
upper triangular part of the array
c
must contain the upper triangular part of the Hermitian matrix and the strictly lower triangular part of
c
is not referenced.
Before entry with
uplo
=
CblasLower
, the leading
n
-by-
n
lower triangular part of the array
c
must contain the lower triangular part of the Hermitian matrix and the strictly upper triangular part of
c
is not referenced.
The imaginary parts of the diagonal elements need not be set, they are assumed to be zero.
ldc
Specifies the leading dimension of
c
as declared in the calling (sub)program. The value of
ldc
must be at least
max(1,
n
)
.
Output Parameters
c
With
uplo
=
CblasUpper
, the upper triangular part of the array
c
is overwritten by the upper triangular part of the updated matrix.
With
uplo
=
CblasLower
, the lower triangular part of the array
c
is overwritten by the lower triangular part of the updated matrix.
The imaginary parts of the diagonal elements 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