CSR SpMV with oneAPI

csr_example.cpp

// compile with:
//   icpx -fsycl csr_example.cpp
//
#include <algorithm>

#include <oneapi/mkl.hpp>
#include <CL/sycl.hpp>

int main(int argc, char const *argv[])
{
    using namespace oneapi::mkl;

    constexpr int NR = 4;
    constexpr int NC = 6;

    std::vector<int> ia{0,2,4,7,8};
    std::vector<int> ja{0,1,1,3,2,3,4,5};
    std::vector<double> va{10,20,30,40,50,60,70,80};

    std::array<double,NC> x;
    std::array<double,NR> y;

    std::fill(x.begin(),x.end(),1.0);

    sycl::device device{sycl::default_selector{}};
    sycl::queue Q{device};
    std::cout << "Running SpMV product on " << device.get_info<sycl::info::device::name>() << ".\n";

    {
        sycl::buffer<double,1> b_x(x.data(),x.size());
        sycl::buffer<double,1> b_y(y.data(),y.size());

        sparse::matrix_handle_t handle;
        sparse::init_matrix_handle(&handle);

        sycl::buffer<int,1> b_ia(ia.data(),NR+1);
        sycl::buffer<int,1> b_ja(ja.data(),ja.size());
        sycl::buffer<double,1> b_va(va.data(),va.size());

        sparse::set_csr_data(handle,NR,NC,index_base::zero,b_ia,b_ja,b_va);
        sparse::optimize_gemv(Q,transpose::N,handle);
        
        const double alpha = 1.0;
        const double beta = 0.0;

        //
        // y := alpha*op(A)*x + beta*y
        //
        sparse::gemv(Q,transpose::N,alpha,handle,b_x,beta,b_y);

        sparse::release_matrix_handle(&handle);

    }

    for (int i = 0; i < y.size(); ++i) {
        std::cout << "y[" << i << "] = " << y[i] << '\n';
    }

    return 0;
}