TheRock/rocm-libraries/projects/rocalution/clients/samples/cg-amg.cpp

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#include <cstdlib>
#include <iostream>
#include <rocalution/rocalution.hpp>

using namespace rocalution;

int main(int argc, char* argv[])
{
    // Check command line parameters
    if(argc == 1)
    {
        std::cerr << argv[0] << " <matrix> [Num threads]" << std::endl;
        exit(1);
    }

    // Initialize rocALUTION
    init_rocalution();

    // Check command line parameters for number of OMP threads
    if(argc > 2)
    {
        set_omp_threads_rocalution(atoi(argv[2]));
    }

    // Print rocALUTION info
    info_rocalution();

    // rocALUTION objects
    LocalVector<double> x;
    LocalVector<double> rhs;
    LocalVector<double> e;
    LocalMatrix<double> mat;

    // Move objects to accelerator
    mat.MoveToAccelerator();
    x.MoveToAccelerator();
    rhs.MoveToAccelerator();
    e.MoveToAccelerator();

    // Read matrix from MTX file
    mat.ReadFileMTX(std::string(argv[1]));

    // Allocate vectors
    x.Allocate("x", mat.GetN());
    rhs.Allocate("rhs", mat.GetM());
    e.Allocate("e", mat.GetN());

    // Initialize rhs such that A 1 = rhs
    e.Ones();
    mat.Apply(e, &rhs);

    // Initial zero guess
    x.Zeros();

    // Start time measurement
    double tick = rocalution_time();

    // Linear Solver
    CG<LocalMatrix<double>, LocalVector<double>, double> ls;

    // AMG Preconditioner
    SAAMG<LocalMatrix<double>, LocalVector<double>, double> p;

    // Disable verbosity output of AMG preconditioner
    p.Verbose(0);

    // Set solver preconditioner
    ls.SetPreconditioner(p);
    // Set solver operator
    ls.SetOperator(mat);

    // Build solver
    ls.Build();

    // Compute 2 coarsest levels on the host
    p.SetHostLevels(2);

    // Stop time measurement
    double tack = rocalution_time();
    std::cout << "Building took: " << (tack - tick) / 1e6 << " sec" << std::endl;

    // Print matrix info
    mat.Info();

    // Initialize solver tolerances
    ls.Init(1e-8, 1e-8, 1e+8, 10000);

    // Set verbosity output
    ls.Verbose(1);

    // Start time measurement
    tick = rocalution_time();

    // Solve A x = rhs
    ls.Solve(rhs, &x);

    // Stop time measurement
    tack = rocalution_time();
    std::cout << "Solver took: " << (tack - tick) / 1e6 << " sec" << std::endl;

    // Clear solver
    ls.Clear();

    // Compute error L2 norm
    e.ScaleAdd(-1.0, x);
    double error = e.Norm();
    std::cout << "||e - x||_2 = " << error << std::endl;

    // Stop rocALUTION platform
    stop_rocalution();

    return 0;
}