Contents

her2

Computes a rank-2 update of a hermitian matrix.

Description

The her2 routines compute two scalar-vector-vector products and add them to a hermitian matrix. The operation is defined as:

A \leftarrow alpha*x*y^H + conjg(alpha)*y*x^H + A

where:

  • alpha is a scalar

  • A is n x n hermitian matrix

  • x and y are vectors or length n

her2 supports the following precisions:

T

std::complex<float>

std::complex<double>

her2 (Buffer Version)

Syntax

namespace oneapi::mkl::blas::column_major {
    void her2(sycl::queue &queue,
              oneapi::mkl::uplo upper_lower,
              std::int64_t n,
              T alpha,
              sycl::buffer<T,1> &x,
              std::int64_t incx,
              sycl::buffer<T,1> &y,
              std::int64_t incy,
              sycl::buffer<T,1> &a,
              std::int64_t lda)
}

namespace oneapi::mkl::blas::row_major {
    void her2(sycl::queue &queue,
              oneapi::mkl::uplo upper_lower,
              std::int64_t n,
              T alpha,
              sycl::buffer<T,1> &x,
              std::int64_t incx,
              sycl::buffer<T,1> &y,
              std::int64_t incy,
              sycl::buffer<T,1> &a,
              std::int64_t lda)
}

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

Specifies whether matrix A is upper or lower triangular. See Data Types for more details.

n

Number of columns of matrix A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

x

Buffer holding input vector x. Size of the buffer must be at least (1 + (n - 1)*abs(incx)). See Matrix Storage for more details.

incx

Stride of vector x.

y

Buffer holding input/output vector y. Size of the buffer must be at least (1 + (n - 1)*abs(incy)). See Matrix Storage for more details.

incy

Stride of vector y.

a

Buffer holding input matrix A. Size of the buffer must be at least lda * n. See Matrix Storage for more details.

lda

Leading dimension of matrix A. Must be at least n and positive.

Output Parameters

a

Buffer holding updated upper triangular part of the hermitian matrix A if upper_lower=upper, or updated lower triangular part of the hermitian matrix A if upper_lower=lower.

The imaginary parts of the diagonal elements are set to zero.

her2 (USM Version)

Syntax

namespace oneapi::mkl::blas::column_major {
    sycl::event her2(sycl::queue &queue,
                     oneapi::mkl::uplo upper_lower,
                     std::int64_t n,
                     T alpha,
                     const T *x,
                     std::int64_t incx,
                     const T *y,
                     std::int64_t incy,
                     T *a,
                     std::int64_t lda,
                     const std::vector<sycl::event> &dependencies = {})
}

namespace oneapi::mkl::blas::row_major {
    sycl::event her2(sycl::queue &queue,
                     oneapi::mkl::uplo upper_lower,
                     std::int64_t n,
                     T alpha,
                     const T *x,
                     std::int64_t incx,
                     const T *y,
                     std::int64_t incy,
                     T *a,
                     std::int64_t lda,
                     const std::vector<sycl::event> &dependencies = {})
}

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

Specifies whether matrix A is upper or lower triangular. See Data Types for more details.

n

Number of columns of matrix A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

x

Pointer to input vector x. Size of the array holding input vector x must be at least (1 + (n - 1)*abs(incx)). See Matrix Storage for more details.

incx

Stride of vector x.

y

Pointer to input/output vector y. Size of the array holding input/output vector y must be at least (1 + (n - 1)*abs(incy)). See Matrix Storage for more details.

incy

Stride of vector y.

a

Pointer to input matrix A. Size of the array holding input matrix A must be at least lda * n. See Matrix Storage for more details.

lda

Leading dimension of matrix A. Must be at least n and positive.

dependencies

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

Output Parameters

a

Pointer to updated upper triangular part of the hermitian matrix A if upper_lower=upper, or updated lower triangular part of the hermitian matrix A if upper_lower=lower.

The imaginary parts of the diagonal elements are set to zero.

Return Values

Output event to wait on to ensure computation is complete.

her hpmv