Intel® oneAPI Math Kernel Library (oneMKL) - Data Parallel C++ Developer Reference

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hemm

Computes a matrix-matrix product where one input matrix is hermitian and one is general.

Description

The
hemm
 routines compute a scalar-matrix-matrix product and add the result to a scalar-matrix product, where one of the matrices in the multiplication is hermitian. The argument
left_right
 determines if the hermitian matrix,
A
, is on the left of the multiplication (
left_right
 =
side::left
) or on the right (
left_right
 =
side::right
). The operation is defined as:
If (
left_right
 =
side::left
),
LaTex Math image.
If (
left_right
 =
side::right
),
LaTex Math image.
where:
  • alpha
     and
    beta
     are scalars
  • A
     is either
    m
     x
    m
     or
    n
     x
    n
     hermitian matrix
  • B
     and
    C
     are
    m
     x
    n
     matrices
hemm
 supports the following precisions:
T
std::complex<float>
std::complex<double>

hemm (Buffer Version)

Syntax
namespace oneapi::mkl::blas::column_major {
    void hemm(sycl::queue &queue,
              oneapi::mkl::side left_right,
              oneapi::mkl::uplo upper_lower,
              std::int64_t m,
              std::int64_t n,
              T alpha,
              sycl::buffer<T,1> &a,
              std::int64_t lda,
              sycl::buffer<T,1> &b,
              std::int64_t ldb,
              T beta,
              sycl::buffer<T,1> &c,
              std::int64_t ldc)
}
namespace oneapi::mkl::blas::row_major {
    void hemm(sycl::queue &queue,
              oneapi::mkl::side left_right,
              oneapi::mkl::uplo upper_lower,
              std::int64_t m,
              std::int64_t n,
              T alpha,
              sycl::buffer<T,1> &a,
              std::int64_t lda,
              sycl::buffer<T,1> &b,
              std::int64_t ldb,
              T beta,
              sycl::buffer<T,1> &c,
              std::int64_t ldc)
}
Input Parameters
queue
The queue where the routine should be executed.
left_right
Specifies whether matrix
A
 is on the left side or right side of the multiplication. See Data Types for more details.
upper_lower
Specifies whether matrix
A
 is upper or lower triangular. See Data Types for more details.
m
Number of rows of matrix
B
 and matrix
C
. Must be at least zero.
n
Number of columns of matrix
B
 and matrix
C
. Must be at least zero.
alpha
Scaling factor for matrix-matrix product.
a
Buffer holding input matrix
A
. Size of the buffer must be at least
lda
 *
m
 if
left_right
 =
side::left
 or
lda
 *
n
 if
left_right
 =
side::right
. See Matrix Storage for more details.
lda
Leading dimension of matrix
A
. Must be at least
m
 if
left_right
 =
side::left
 or at least
n
 if
left_right
 =
side::right
. Must be positive.
b
Buffer holding input matrix
B
. Size of the buffer must be at least
ldb
 *
n
 if column major layout or at least
ldb
 *
m
 if row major layout is used. See Matrix Storage for more details.
ldb
Leading dimension of matrix
B
. Must be at least
m
 if column major layout or at least
n
 if row major layout is used. Must be positive.
beta
Scaling factor for matrix
C
.
c
Buffer holding input/output matrix
C
. Size of the buffer must be at least
ldc
 *
n
 if column major layout or at least
ldc
 *
m
 if row major layout is used. See Matrix Storage for more details.
ldc
Leading dimension of matrix
C
. Must be at least
m
 if column major layout or at least
n
 if row major layout is used. Must be positive.
Output Parameters
c
Output buffer overwritten by
alpha
 *
A
 *
B
 +
beta
 *
C
 if
left_right
 =
side::left
 or
alpha
 *
B
 *
A
 +
beta
 *
C
 if
left_right
 =
side::right
.
If
beta
 = 0, matrix
C
 does not need to be initialized before calling
hemm
.

hemm (Buffer Version)

Syntax
namespace oneapi::mkl::blas::column_major {
    sycl::event hemm(sycl::queue &queue,
                     oneapi::mkl::side left_right,
                     oneapi::mkl::uplo upper_lower,
                     std::int64_t m,
                     std::int64_t n,
                     T alpha,
                     const T* a,
                     std::int64_t lda,
                     const T* b,
                     std::int64_t ldb,
                     T beta,
                     T* c,
                     std::int64_t ldc,
                     const std::vector<sycl::event> &dependencies = {})
}
namespace oneapi::mkl::blas::row_major {
    sycl::event hemm(sycl::queue &queue,
                     oneapi::mkl::side left_right,
                     oneapi::mkl::uplo upper_lower,
                     std::int64_t m,
                     std::int64_t n,
                     T alpha,
                     const T* a,
                     std::int64_t lda,
                     const T* b,
                     std::int64_t ldb,
                     T beta,
                     T* c,
                     std::int64_t ldc,
                     const std::vector<sycl::event> &dependencies = {})
}
Input Parameters
queue
The queue where the routine should be executed.
left_right
Specifies whether matrix
A
 is on the left side or right side of the multiplication. See Data Types for more details.
upper_lower
Specifies whether matrix
A
 is upper or lower triangular. See Data Types for more details.
m
Number of rows of matrix
B
 and matrix
C
. Must be at least zero.
n
Number of columns of matrix
B
 and matrix
C
. Must be at least zero.
alpha
Scaling factor for matrix-matrix product.
a
Pointer to input matrix
A
. Size of the array must be at least
lda
 *
m
 if
left_right
 =
side::left
 or
lda
 *
n
 if
left_right
 =
side::right
. See Matrix Storage for more details.
lda
Leading dimension of matrix
A
. Must be at least
m
 if
left_right
 =
side::left
 or at least
n
 if
left_right
 =
side::right
. Must be positive.
b
Pointer to input matrix
B
. Size of the array must be at least
ldb
 *
n
 if column major layout or at least
ldb
 *
m
 if row major layout is used. See Matrix Storage for more details.
ldb
Leading dimension of matrix
B
. Must be at least
m
 if column major layout or at least
n
 if row major layout is used. Must be positive.
beta
Scaling factor for matrix
C
.
c
Pointer to input/output matrix
C
. Size of the array must be at least
ldc
 *
n
 if column major layout or at least
ldc
 *
m
 if row major layout is used. See Matrix Storage for more details.
ldc
Leading dimension of matrix
C
. Must be at least
m
 if column major layout or at least
n
 if row major layout is used. Must be positive.
dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
c
Pointer to output matrix overwritten by
alpha
 *
A
 *
B
 +
beta
 *
C
 if
left_right
 =
side::left
 or
alpha
 *
B
 *
A
 +
beta
 *
C
 if
left_right
 =
side::right
.
If
beta
 = 0, matrix
C
 does not need to be initialized before calling
hemm
.
Return Values
Output event to wait on to ensure computation is complete.

Product and Performance Information

1

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