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/*!
 * \file
 *
 * \brief test for the one-phase CC model
 */
#include <config.h>

#include "1pproblem.hh"

#include <ctime>
#include <iostream>

#include <dune/common/parallel/mpihelper.hh>
#include <dune/common/timer.hh>
#include <dune/grid/io/file/dgfparser/dgfexception.hh>
#include <dune/grid/io/file/vtk.hh>
#include <dune/istl/io.hh>

#include <dumux/common/properties.hh>
#include <dumux/common/parameters.hh>
#include <dumux/common/dumuxmessage.hh>
#include <dumux/common/defaultusagemessage.hh>

#include <dumux/linear/seqsolverbackend.hh>

#include <dumux/assembly/fvassembler.hh>

#include <dumux/io/vtkoutputmodule.hh>
#include <dumux/io/grid/gridmanager.hh>

int main(int argc, char** argv) try
{
    using namespace Dumux;

    // define the type tag for this problem
    using TypeTag = Properties::TTag::OnePIncompressible;

    ////////////////////////////////////////////////////////////
    ////////////////////////////////////////////////////////////

    // initialize MPI, finalize is done automatically on exit
    const auto& mpiHelper = Dune::MPIHelper::instance(argc, argv);

    // print dumux start message
    if (mpiHelper.rank() == 0)
        DumuxMessage::print(/*firstCall=*/true);

    // initialize parameter tree
    Parameters::init(argc, argv);

    //////////////////////////////////////////////////////////////////////
    // try to create a grid (from the given grid file or the input file)
    /////////////////////////////////////////////////////////////////////

    GridManager<GetPropType<TypeTag, Properties::Grid>> gridManager;
    gridManager.init();

    ////////////////////////////////////////////////////////////
    // run stationary linear problem on this grid
    ////////////////////////////////////////////////////////////

    // we compute on the leaf grid view
    const auto& leafGridView = gridManager.grid().leafGridView();

    // create the finite volume grid geometry
    using FVGridGeometry = GetPropType<TypeTag, Properties::GridGeometry>;
    auto fvGridGeometry = std::make_shared<FVGridGeometry>(leafGridView);
    fvGridGeometry->update();

    // the problem (initial and boundary conditions)
    using Problem = GetPropType<TypeTag, Properties::Problem>;
    auto problem = std::make_shared<Problem>(fvGridGeometry);

    // the solution vector
    using SolutionVector = GetPropType<TypeTag, Properties::SolutionVector>;
    SolutionVector x(fvGridGeometry->numDofs());

    // the grid variables
    using GridVariables = GetPropType<TypeTag, Properties::GridVariables>;
    auto gridVariables = std::make_shared<GridVariables>(problem, fvGridGeometry);
    gridVariables->init(x);

    // intialize the vtk output module
    VtkOutputModule<GridVariables, SolutionVector> vtkWriter(*gridVariables, x, problem->name());
    using VelocityOutput = GetPropType<TypeTag, Properties::VelocityOutput>;
    vtkWriter.addVelocityOutput(std::make_shared<VelocityOutput>(*gridVariables));
    using IOFields = GetPropType<TypeTag, Properties::IOFields>;
    IOFields::initOutputModule(vtkWriter); //!< Add model specific output fields
    vtkWriter.write(0.0);
    
    Dune::Timer timer;

    // TODO: dumux-course-task
    // change the differentiation method to analytic by changing from DiffMethod::numeric to DiffMethod::analytic

    // the assembler for stationary problems
    using Assembler = FVAssembler<TypeTag, DiffMethod::analytic>;
    auto assembler = std::make_shared<Assembler>(problem, fvGridGeometry, gridVariables);

    // the linear solver
    using LinearSolver = ILU0BiCGSTABBackend;
    auto linearSolver = std::make_shared<LinearSolver>();

    // the discretization matrices for stationary linear problems
    using JacobianMatrix = GetPropType<TypeTag, Properties::JacobianMatrix>;
    auto A = std::make_shared<JacobianMatrix>();
    auto r = std::make_shared<SolutionVector>();
    assembler->setLinearSystem(A, r);
    assembler->assembleJacobianAndResidual(x);

    // we solve Ax = -r to save update and copy
    (*r) *= -1.0;
    linearSolver->solve(*A, x, *r);

    // the grid variables need to be up to date for subsequent output
    gridVariables->update(x);

    // write vtk output
    vtkWriter.write(1.0);

    timer.stop();

    const auto& comm = Dune::MPIHelper::getCollectiveCommunication();
    std::cout << "Simulation took " << timer.elapsed() << " seconds on "
              << comm.size() << " processes.\n"
              << "The cumulative CPU time was " << timer.elapsed()*comm.size() << " seconds.\n";

    ////////////////////////////////////////////////////////////
    // print dumux message to say goodbye
    ////////////////////////////////////////////////////////////

    // print dumux end message
    if (mpiHelper.rank() == 0)
        DumuxMessage::print(/*firstCall=*/false);

    return 0;

}
catch (Dumux::ParameterException &e)
{
    std::cerr << std::endl << e << " ---> Abort!" << std::endl;
    return 1;
}
catch (Dune::DGFException & e)
{
    std::cerr << "DGF exception thrown (" << e <<
                 "). Most likely, the DGF file name is wrong "
                 "or the DGF file is corrupted, "
                 "e.g. missing hash at end of file or wrong number (dimensions) of entries."
                 << " ---> Abort!" << std::endl;
    return 2;
}
catch (Dune::Exception &e)
{
    std::cerr << "Dune reported error: " << e << " ---> Abort!" << std::endl;
    return 3;
}
catch (...)
{
    std::cerr << "Unknown exception thrown! ---> Abort!" << std::endl;
    return 4;
}