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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>

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.

stridex

Stride between different X vectors.

y

Buffer holding input/output vectors Y with size stridey * batch_size.

incy

Stride of vector Y.

stridey

Stride between different Y vectors.

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,
                           std::int64_t *n,
                           T *alpha,
                           const T **x,
                           std::int64_t *incx,
                           T **y,
                           std::int64_t *incy,
                           std::int64_t group_count,
                           std::int64_t *group_size,
                           const std::vector<sycl::event> &dependencies = {})
}

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

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.

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,
                           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,
                           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.

x

Pointer to input vectors X with size stridex * batch_size.

incx

Stride of vector X.

stridex

Stride between different X vectors.

y

Pointer to input/output vectors Y with size stridey * batch_size.

incy

Stride of vector Y.

stridey

Stride between different Y vectors.

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.

Output Parameters

y

Output vectors, overwritten by batch_size axpy operations of the form alpha * X + 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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