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oneapi::mkl::sparse::gemv

Computes a sparse matrix-dense vector product.

Description

Note

Refer to Supported Types for a list of supported <fp> and <intType> and refer to Exceptions for a detailed description of the 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:

\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}

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 (
        cl::sycl::queue &queue,
        oneapi::mkl::transpose transpose_flag,
        const fp alpha,
        oneapi::mkl::sparse::matrix_handle_t handle,
        cl::sycl::buffer<fp, 1> &x,
        const fp beta,
        cl::sycl::buffer<fp, 1> &y)
}

Using USM pointers:

namespace oneapi::mkl::sparse {
    cl::sycl::event gemv (
        cl::sycl::queue &queue,
        oneapi::mkl::transpose transpose_flag,
        const fp alpha,
        oneapi::mkl::sparse::matrix_handle_t handle,
        const fp *x,
        fp beta,
        fp *y,
        const std::vector<cl::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<cl::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)

cl::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
oneapi::mkl::sparse::optimize_trsv oneapi::mkl::sparse::gemvdot