Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

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

cblas_?hemm

Computes a matrix-matrix product where one input matrix is Hermitian.

Syntax

void
cblas_chemm
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_SIDE
side
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
m
,
const
MKL_INT
n
,
const
void
*alpha
,
const
void
*a
,
const
MKL_INT
lda
,
const
void
*b
,
const
MKL_INT
ldb
,
const
void
*beta
,
void
*c
,
const
MKL_INT
ldc
);
void
cblas_zhemm
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_SIDE
side
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
m
,
const
MKL_INT
n
,
const
void
*alpha
,
const
void
*a
,
const
MKL_INT
lda
,
const
void
*b
,
const
MKL_INT
ldb
,
const
void
*beta
,
void
*c
,
const
MKL_INT
ldc
);
Include Files
  • mkl.h
Description
The
?hemm
 routines compute a scalar-matrix-matrix product using a Hermitian matrix
A
 and a general matrix
B
 and add the result to a scalar-matrix product using a general matrix
C
. The operation is defined as
C := alpha*A*B + beta*C
or 
C := alpha*B*A + beta*C
where:
alpha
 and
beta
 are scalars,
A
 is a Hermitian matrix,
B
 and
C
 are
m
-by-
n
 matrices.
Input Parameters
Layout
Specifies whether two-dimensional array storage is row-major (
CblasRowMajor
) or column-major (
CblasColMajor
).
side
Specifies whether the Hermitian matrix
A
 appears on the left or right in the operation as follows:
if
side
 =
CblasLeft
, then
C
 :=
alpha
*
A
*
B
 +
beta
*
C
;
if
side
 =
CblasRight
, then
C
 :=
alpha
*
B
*
A
 +
beta
*
C
.
uplo
Specifies whether the upper or lower triangular part of the Hermitian matrix
A
 is used:
If
uplo
 =
CblasUpper
, then the upper triangular part of the Hermitian matrix
A
 is used.
If
uplo
 =
CblasLower
, then the low triangular part of the Hermitian matrix
A
 is used.
m
Specifies the number of rows of the matrix
C
.
The value of
m
 must be at least zero.
n
Specifies the number of columns of the matrix
C
.
The value of
n
 must be at least zero.
alpha
Specifies the scalar
alpha
.
a
Array, size
lda
*
ka
, where
ka
 is
m
 when
side
 =
CblasLeft
and is
n
 otherwise. Before entry with
side
 =
CblasLeft
, the
m
-by-
m
 part of the array
a
 must contain the Hermitian matrix, such that when
uplo
 =
CblasUpper
, the leading
m
-by-
m
 upper triangular part of the array
a
 must contain the upper triangular part of the Hermitian matrix and the strictly lower triangular part of
a
 is not referenced, and when
uplo
 =
CblasLower
, the leading
m
-by-
m
 lower triangular part of the array
a
 must contain the lower triangular part of the Hermitian matrix, and the strictly upper triangular part of
a
 is not referenced.
Before entry with
side
 =
CblasRight
, the
n
-by-
n
 part of the array
a
 must contain the Hermitian matrix, such that when
uplo
 =
CblasUpper
, the leading
n
-by-
n
 upper triangular part of the array
a
 must contain the upper triangular part of the Hermitian matrix and the strictly lower triangular part of
a
 is not referenced, and when
uplo
 =
CblasLower
, the leading
n
-by-
n
 lower triangular part of the array
a
 must contain the lower triangular part of the Hermitian matrix, and the strictly upper triangular part of
a
 is not referenced. The imaginary parts of the diagonal elements need not be set, they are assumed to be zero.
lda
Specifies the leading dimension of
a
 as declared in the calling (sub) program. When
side
 =
CblasLeft
then
lda
 must be at least
max(1,
m
)
, otherwise
lda
 must be at least
max(1,
n
)
.
b
For
Layout
 =
CblasColMajor
: array, size
ldb
*
n
.
The leading
m
-by-
n
 part of the array
b
 must contain the matrix
B
.
For
Layout
 =
CblasRowMajor
: array, size
ldb
*
m
. The leading
n
-by-
m
 part of the array
b
 must contain the matrix
B
ldb
Specifies the leading dimension of
b
 as declared in the calling (sub)program.
When
Layout
 =
CblasColMajor
,
ldb
 must be at least
max(1,
m
)
; otherwise,
ldb
 must be at least
max(1,
n
)
 .
beta
Specifies the scalar
beta
.
When
beta
 is supplied as zero, then
c
 need not be set on input.
c
For
Layout
 =
CblasColMajor
: array, size
ldc
*
n
. Before entry, the leading
m
-by-
n
 part of the array
c
 must contain the matrix
C
, except when
beta
 is zero, in which case
c
 need not be set on entry.
For
Layout
 =
CblasRowMajor
: array, size
ldc
*
m
. Before entry, the leading
n
-by-
m
 part of the array
c
 must contain the matrix
C
, except when
beta
 is zero, in which case
c
 need not be set on entry.
ldc
Specifies the leading dimension of
c
 as declared in the calling (sub)program.
When
Layout
 =
CblasColMajor
,
ldc
 must be at least
max(1,
m
)
; otherwise,
ldc
 must be at least
max(1,
n
)
 .
Output Parameters
c
Overwritten by the
m
-by-
n
 updated matrix.

Product and Performance Information

1

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