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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). Depending on left_right, the operation is defined as:

\[C \leftarrow alpha*A*B + beta*C\]

or

\[C \leftarrow alpha*B*A + beta*C\]

where:

alpha and beta are scalars,

A is a Hermitian matrix, either m-by-m or n-by-n matrices,

B and C are m-by-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,
              onemkl::side left_right,
              onemkl::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,
              onemkl::side left_right,
              onemkl::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 A is on the left side of the multiplication (side::left) or on the right side (side::right). See oneMKL defined datatypes for more details.

uplo

Specifies whether A’s data is stored in its upper or lower triangle. See oneMKL defined datatypes for more details.

m

Specifies the number of rows of the matrix B and C.

The value of m must be at least zero.

n

Specifies the number of columns of the matrix B and C.

The value of n must be at least zero.

alpha

Scaling factor for the matrix-matrix product.

a

Buffer holding input matrix A. Must have size at least lda*m if A is on the left of the multiplication, or lda*n if A is on the right. See Matrix Storage for more details.

lda

Leading dimension of A. Must be at least m if A is on the left of the multiplication, or at least n if A is on the right. Must be positive.

b

Buffer holding input matrix B. Must have size at least ldb*n if column major layout is used to store matrices or at least ldb*m if row major layout is used to store matrices. See Matrix Storage for more details.

ldb

Leading dimension of B. It must be positive and at least m if column major layout is used to store matrices or at least n if column major layout is used to store matrices.

beta

Scaling factor for matrix C.

c

The buffer holding the input/output matrix C. It must have a size of at least ldc*n if column major layout is used to store matrices or at least ldc*m if row major layout is used to store matrices . See Matrix Storage for more details.

ldc

The leading dimension of C. It must be positive and at least m if column major layout is used to store matrices or at least n if column major layout is used to store matrices.

Output Parameters

c

Output buffer, overwritten by alpha*A*B + beta*C (left_right = side::left) or alpha*B*A + beta*C (left_right = side::right).

Notes

If beta = 0, matrix C does not need to be initialized before calling hemm.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::mkl::invalid_argument

oneapi::mkl::unsupported_device

oneapi::mkl::host_bad_alloc

oneapi::mkl::device_bad_alloc

oneapi::mkl::unimplemented

hemm (USM Version)

Syntax

namespace oneapi::mkl::blas::column_major {
    sycl::event hemm(sycl::queue &queue,
                     onemkl::side left_right,
                     onemkl::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 sycl::vector_class<sycl::event> &dependencies = {})
}

namespace oneapi::mkl::blas::row_major {
    sycl::event hemm(sycl::queue &queue,
                     onemkl::side left_right,
                     onemkl::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 sycl::vector_class<sycl::event> &dependencies = {})
}

Input Parameters

queue

The queue where the routine should be executed.

left_right

Specifies whether A is on the left side of the multiplication (side::left) or on the right side (side::right). See oneMKL defined datatypes for more details.

uplo

Specifies whether A’s data is stored in its upper or lower triangle. See oneMKL defined datatypes for more details.

m

Specifies the number of rows of the matrix B and C.

The value of m must be at least zero.

n

Specifies the number of columns of the matrix B and C.

The value of n must be at least zero.

alpha

Scaling factor for the matrix-matrix product.

a

Pointer to input matrix A. Must have size at least lda*m if A is on the left of the multiplication, or lda*n if A is on the right. See Matrix Storage for more details.

lda

Leading dimension of A. Must be at least m if A is on the left of the multiplication, or at least n if A is on the right. Must be positive.

b

Pointer to input matrix B. Must have size at least ldb*n if column major layout is used to store matrices or at least ldb*m if row major layout is used to store matrices. See Matrix Storage for more details.

ldb

Leading dimension of B. It must be positive and at least m if column major layout is used to store matrices or at least n if column major layout is used to store matrices.

beta

Scaling factor for matrix C.

c

The pointer to input/output matrix C. It must have a size of at least ldc*n if column major layout is used to store matrices or at least ldc*m if row major layout is used to store matrices . See Matrix Storage for more details.

ldc

The leading dimension of C. It must be positive and at least m if column major layout is used to store matrices or at least n if column major layout is used to store matrices.

dependencies

List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.

Output Parameters

c

Pointer to the output matrix, overwritten by alpha*A*B + beta*C (left_right = side::left) or alpha*B*A + beta*C (left_right = side::right).

Notes

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.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::mkl::invalid_argument

oneapi::mkl::unsupported_device

oneapi::mkl::host_bad_alloc

oneapi::mkl::device_bad_alloc

oneapi::mkl::unimplemented

Parent topic: BLAS Level 3 Routines

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