oneapi::mkl::sparse::gemv

Computes a sparse matrix-dense vector product.

Description

Note

Refer to Sparse BLAS Supported Data and Integer Types for a list of supported <DATA_TYPE> and <INT_TYPE> data and integer types and refer to Error Handling for a detailed description of the possible exceptions thrown.

The oneapi::mkl::sparse::gemv routine computes a sparse matrix-dense vector product defined as

\[y \leftarrow \alpha \cdot\text{op}(A)\cdot x + \beta\cdot y\]

where \(\alpha\) and \(\beta\) are scalars, \(A\) is a general sparse matrix of dimensions num_rows rows and num_cols columns and \(op()\) is a matrix modifier:

\[\begin{split}\text{op}(A) = \begin{cases} A,& \text{ oneapi::mkl::transpose::nontrans}\\ A^{T},& \text{ oneapi::mkl::transpose::trans}\\A^{H},& \text{ oneapi::mkl::transpose::conjtrans} \end{cases}\end{split}\]

The dense vectors \(x\) and \(y\) are appropriately sized based on matrix product dimensions of \(\text{op}(A)\).

API

Syntax

Note

Currently, complex types are not supported.

Using SYCL buffers:

namespace oneapi::mkl::sparse {
    void gemv (
        sycl::queue &queue,
        oneapi::mkl::transpose transpose_flag,
        const DATA_TYPE alpha,
        oneapi::mkl::sparse::matrix_handle_t handle,
        sycl::buffer<DATA_TYPE, 1> &x,
        const DATA_TYPE beta,
        sycl::buffer<DATA_TYPE, 1> &y)
}

Using USM pointers:

namespace oneapi::mkl::sparse {
    sycl::event gemv (
        sycl::queue &queue,
        oneapi::mkl::transpose transpose_flag,
        const DATA_TYPE alpha,
        oneapi::mkl::sparse::matrix_handle_t handle,
        const DATA_TYPE *x,
        DATA_TYPE beta,
        DATA_TYPE *y,
        const std::vector<sycl::event> &dependencies= {})
}

Include Files

  • oneapi/mkl/spblas.hpp

Input Parameters

queue

Specifies the SYCL command queue which will be used for SYCL kernels execution.

transpose_flag

Specifies operation op() on input matrix.

oneapi::mkl::transpose::nontrans

Non-transpose, \(\text{op}(A) = A\).

oneapi::mkl::transpose::trans

Transpose, \(\text{op}(A) = A^{T}\).

oneapi::mkl::transpose::conjtrans

Conjugate transpose, \(\text{op}(A) = A^{H}\).

Note

Currently, the only supported case for operation is oneapi::mkl::transpose::nontrans.

alpha

Specifies the scalar, \(\alpha\).

handle

Handle to object containing sparse matrix and other internal data. Created using one of the oneapi::mkl::sparse::set_<sparse_matrix_type>_data routines.

Note

Currently, the only supported case for <sparse_matrix_type> is csr.

x

SYCL buffer or device-accessible USM pointer of size at least equal to the number of columns of input matrix if transpse_flag = oneapi::mkl::transpose::nontrans and at least the number of rows of input matrix otherwise.

beta

Specifies the scalar, \(\beta\).

y

SYCL buffer or device-accessible USM pointer of size at least equal to the number of rows of the input matrix if transpose_flag = oneapi::mkl::transpose::nontrans and at least the number of columns of the input matrix otherwise.

dependencies

A vector of type std::vector<sycl::event> containing the list of events that the oneapi::mkl::sparse::gemv routine depends on.

Output Parameters

y

Overwritten by the updated vector \(y\).

Return Values (USM Only)

sycl::event

SYCL event which can be waited upon or added as a dependency for the completion of the gemv routine.

Examples

An example of how to use oneapi::mkl::sparse::gemv with SYCL buffers or USM pointers can be found in the oneMKL installation directory, under:

examples/dpcpp/sparse_blas/source/sparse_gemv.cpp
examples/dpcpp/sparse_blas/source/sparse_gemv_usm.cpp