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axpy

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. The operation is defined as:

y \leftarrow alpha*x+y

where:

  • x and y are vectors of n elements

  • alpha is a scalar

axpy supports the following precisions:

T

float

double

std::complex<float>

std::complex<double>

axpy (Buffer Version)

Syntax

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

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

Input Parameters

queue

The queue where the routine should be executed.

n

Number of elements in vector x.

alpha

Specifies scalar alpha.

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 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.

Output Parameters

y

Buffer holding updated vector y.

Examples

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

examples/dpcpp/blas/source/axpy.cpp

axpy (USM Version)

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 std::vector<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 std::vector<sycl::event> &dependencies = {})
}

Input Parameters

queue

The queue where the routine should be executed.

n

Number of elements in vector x.

alpha

Specifies scalar alpha.

x

Pointer to input vector x. Size of the array holding 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 vector y. Size of the array holding vector y must be 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 updated vector y.

Return Values

Output event to wait on to ensure computation is complete.

asum copy