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axpby

Computes a vector-scalar product added to a scaled-vector.

Description

The axpby routines compute two scalar-vector product and add them:

\[y \leftarrow beta * y + alpha * x\]

where x and y are vectors of n elements and alpha and beta are scalars.

axpby supports the following precisions.

T

float

double

std::complex<float>

std::complex<double>

axpby (Buffer Version)

Syntax

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

namespace oneapi::mkl::blas::row_major {
    void axpby(sycl::queue &queue,
              std::int64_t n,
              T alpha,
              sycl::buffer<T,1> &x, std::int64_t incx,
              T beta,
              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 and y.

alpha

Specifies the scalar alpha.

x

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

incx

Stride between two consecutive elements of the x vector.

beta

Specifies the scalar beta.

y

Buffer holding input vector y. The buffer must be of size at least (1 + (n – 1)*abs(incy)). See Matrix Storage for more details.

incy

Stride between two consecutive elements of the y vector.

Output Parameters

y

Buffer holding the updated vector y.

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

axpby (USM Version)

Syntax

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

namespace oneapi::mkl::blas::row_major {
    sycl::event axpby(sycl::queue &queue,
                     std::int64_t n,
                     T alpha,
                     const T *x, std::int64_t incx,
                     const T beta,
                     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 and y.

alpha

Specifies the scalar alpha.

beta

Specifies the scalar beta.

x

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

incx

Stride between consecutive elements of the x vector.

y

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

incy

Stride between consecutive elements of the y vector.

dependencies

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

Output Parameters

y

Array holding the updated vector y.

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-like Extensions

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