axpy (USM Version)

Computes a vector-scalar product and adds the result to a vector.

Description

The axpy routines compute a scalar-vector product and add the result to a vector:

y \leftarrow alpha*x+y

where:

  • x and y are vectors of n elements,

  • alpha is a scalar.

API

Syntax

namespace oneapi::mkl::blas::column_major {
    sycl::event axpy(sycl::queue &queue,
                     std::int64_t n,
                     T alpha,
                     const T *x,
                     std::int64_t incx,
                     T *y,
                     std::int64_t incy,
                     const sycl::vector_class<sycl::event> &dependencies = {})
}
namespace oneapi::mkl::blas::row_major {
    sycl::event axpy(sycl::queue &queue,
                     std::int64_t n,
                     T alpha,
                     const T *x,
                     std::int64_t incx,
                     T *y,
                     std::int64_t incy,
                     const sycl::vector_class<sycl::event> &dependencies = {})
}

The USM version of axpy supports the following precisions and devices.

T

Devices Supported

float

Host, CPU, and GPU

double

Host, CPU, and GPU

std::complex<float>

Host, CPU, and GPU

std::complex<double>

Host, CPU, and GPU

Input Parameters

exec_queue

The queue where the routine should be executed.

n

Number of elements in vector x.

alpha

Specifies the scalar alpha.

x

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

incx

Stride of vector x.

y

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

incy

Stride of vector y.

dependencies

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

Output Parameters

y

Pointer to the updated vector y.

Return Values

Output event to wait on to ensure computation is complete.

Examples

An example of how to use axpy can be found in the oneMKL installation directory, under:

examples/dpcpp/blas/source/axpy.cpp