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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:
LaTex Math image.
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.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.