axpy_batch#

Computes a group of axpy operations.

Description

The axpy_batch routines are batched versions of axpy, performing multiple axpy operations in a single call. Each axpy operation adds a scalar-vector product to a vector.

axpy_batch supports the following precisions for data.

T

float

double

std::complex<float>

std::complex<double>

T
`float`
`double`
`std::complex<float>`
`std::complex<double>`

axpy_batch (Buffer Version)#

Description

The buffer version of axpy_batch supports only the strided API.

The strided API operation is defined as:

for i = 0 … batch_size – 1
   X and Y are vectors at offset i * stridex, i * stridey in x and y
   Y := alpha * X + Y
end for

where:

alpha is scalar,

X and Y are vectors.

Strided API

Syntax

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

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

Input Parameters

queue: The queue where the routine should be executed.
n: Number of elements in X and Y.
alpha: Specifies the scalar alpha.
x: Buffer holding input vectors X with size stridex * batch_size.
incx: Stride of vector X. Must not be zero.
stridex: Stride between different X vectors. Must be at least zero.
y: Buffer holding input/output vectors Y with size stridey * batch_size.
incy: Stride of vector Y. Must not be zero.
stridey: Stride between different Y vectors. Must be at least (1 + (n-1)*abs(incy)).
batch_size: Specifies the number of axpy operations to perform.

Output Parameters

y: Output buffer, overwritten by batch_size axpy operations of the form alpha * X + 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

axpy_batch (USM Version)#

Description

The USM version of axpy_batch supports the group API and strided API.

The group API operation is defined as

idx = 0
for i = 0 … group_count – 1
    for j = 0 … group_size – 1
        X and Y are vectors in x[idx] and y[idx]
        Y := alpha[i] * X + Y
        idx := idx + 1
    end for
end for

The strided API operation is defined as

for i = 0 … batch_size – 1
   X and Y are vectors at offset i * stridex, i * stridey in x and y
   Y := alpha * X + Y
end for

where:

alpha is scalar,

X and Y are vectors.

For group API, x and y arrays contain the pointers for all the input vectors. The total number of vectors in x and y are given by:

\[total\_batch\_count = \sum_{i=0}^{group\_count-1}group\_size[i]\]

For strided API, x and y arrays contain all the input vectors. The total number of vectors in x and y are given by the batch_size parameter.

Group API

Syntax

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

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

Input Parameters

queue: The queue where the routine should be executed.
n: Array of group_count integers. n[i] specifies the number of elements in vectors X and Y for every vector in group i.
alpha: Array of group_count scalar elements. alpha[i] specifies the scaling factor for vector X in group i.
x: Array of pointers to input vectors X with size total_batch_count. The size of array allocated for the X vector of the group i must be at least (1 + (n[i] – 1)*abs(incx[i])). See Matrix Storage for more details.
incx: Array of group_count integers. incx[i] specifies the stride of vector X in group i. Must not be zero.
y: Array of pointers to input/output vectors Y with size total_batch_count. The size of array allocated for the Y vector of the group i must be at least (1 + (n[i] – 1)*abs(incy[i])). See Matrix Storage for more details.
incy: Array of group_count integers. incy[i] specifies the stride of vector Y in group i. Must not be zero.
group_count: Number of groups. Must be at least 0.
group_size: Array of group_count integers. group_size[i] specifies the number of axpy operations in group i. Each element in group_size must be at least 0.
dependencies: List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.

Output Parameters

y: Array of pointers holding the Y vectors, overwritten by total_batch_count axpy operations of the form alpha * X + Y.

Return Values

Output event to wait on to ensure computation is complete.

Strided API

Syntax

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

namespace oneapi::mkl::blas::row_major {
    sycl::event axpy_batch(sycl::queue &queue,
                           std::int64_t n,
                           value_or_pointer<T> alpha,
                           const T *x,
                           std::int64_t incx,
                           std::int64_t stridex,
                           T *y,
                           std::int64_t incy,
                           std::int64_t stridey,
                           std::int64_t batch_size,
                           const std::vector<sycl::event> &dependencies = {})
}

Input Parameters

queue: The queue where the routine should be executed.
n: Number of elements in X and Y.
alpha: Specifies the scalar alpha. See Scalar Arguments in BLAS for more details.
x: Pointer to input vectors X with size stridex * batch_size.
incx: Stride of vector X. Must not be zero.
stridex: Stride between different X vectors. Must be at least zero.
y: Pointer to input/output vectors Y with size stridey * batch_size.
incy: Stride of vector Y. Must not be zero.
stridey: Stride between different Y vectors. Must be at least (1 + (n-1)*abs(incy)).
batch_size: Specifies the number of axpy operations to perform.
dependencies: List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.