her2¶

Computes a rank-2 update of a Hermitian matrix.

her2 supports the following precisions.

T

std::complex<float>

std::complex<double>

Description

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

A <- alpha*x*y ^H + conjg(alpha)*y*x ^H + A

where:

alpha is a scalar,

A is an n-by-n Hermitian matrix.

x and y are vectors or length n.

her2 (Buffer Version)¶

Syntax

void onemkl::blas::her2(sycl::queue &queue, onemkl::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 A is upper or lower triangular. See oneMKL defined datatypes for more details.
n: Number of columns of A. Must be at least zero.
alpha: Scaling factor for the matrix-vector product.
x: Buffer holding input vector x. The buffer must be of size at least (1 + (n - 1)*abs(incx)). See Matrix and Vector Storage for more details.
incx: Stride of vector x.
y: Buffer holding input/output vector y. The buffer must be of size at least (1 + (n - 1)*abs(incy)). See Matrix and Vector Storage for more details.
incy: Stride of vector y.
a: Buffer holding input matrix A. Must have size at least lda*n. See Matrix and Vector Storage for more details.
lda: Leading dimension of matrix A. Must be at least n, and positive.

Output Parameters

a

Buffer holding the updated upper triangular part of the Hermitian matrix A if upper_lower = upper, or the 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

sycl::event onemkl::blas::her2(sycl::queue &queue, onemkl::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 sycl::vector_class<sycl::event> &dependencies = {})¶

Input Parameters

queue: The queue where the routine should be executed.
upper_lower: Specifies whether A is upper or lower triangular. See oneMKL defined datatypes for more details.
n: Number of columns of A. Must be at least zero.
alpha: Scaling factor for the matrix-vector product.
x: Pointer to input vector x. The array holding input vector x must be of size at least (1 + (n - 1)*abs(incx)). See Matrix and Vector Storage for more details.
incx: Stride of vector x.
y: Pointer to input/output vector y. The array holding input/output vector y must be of size at least (1 + (n - 1)*abs(incy)). See Matrix and Vector Storage for more details.
incy: Stride of vector y.
a: Pointer to input matrix A. The array holding input matrix A must have size at least lda*n. See Matrix and Vector 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 the updated upper triangular part of the Hermitian matrix A if upper_lower = upper, or the 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.

Parent topic: BLAS Level 2 Routines