// @HEADER
// *****************************************************************************
//            NOX: An Object-Oriented Nonlinear Solver Package
//
// Copyright 2002 NTESS and the NOX contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

// 1D Finite Element Test Problem
/* Solves the nonlinear equation:
 *
 * d2u
 * --- - k * u**2 = 0
 * dx2
 *
 * subject to @ x=0, u=1
 */

// NOX Objects
#include "NOX.H"
#include "NOX_Epetra.H"

// Trilinos Objects
#ifdef HAVE_MPI
#include "Epetra_MpiComm.h"
#else
#include "Epetra_SerialComm.h"
#endif
#include "Epetra_Map.h"
#include "Epetra_Vector.h"
#include "Epetra_RowMatrix.h"
#include "Epetra_CrsMatrix.h"
#include "Epetra_Map.h"
#include "Epetra_LinearProblem.h"
#include "AztecOO.h"

// User's application specific files
#include "1DfemInterface.H"
#include "1DfemPrePostOperator.H"

#include "Teuchos_ParameterList.hpp"
#include "Teuchos_StandardCatchMacros.hpp"

using namespace std;

int main(int argc, char *argv[])
{
  // Initialize MPI
  Teuchos::GlobalMPISession session(&argc, &argv, NULL);

  bool success = false;
  bool verbose = false;
  try {
  // Create a communicator for Epetra objects
#ifdef HAVE_MPI
  Epetra_MpiComm Comm( MPI_COMM_WORLD );
#else
  Epetra_SerialComm Comm;
#endif

  // Get the process ID and the total number of processors
  int MyPID = Comm.MyPID();
  int NumProc = Comm.NumProc();

  // Check verbosity level
  if (argc > 1)
    if (argv[1][0]=='-' && argv[1][1]=='v')
      verbose = true;

  // Get the number of elements from the command line
  int NumGlobalElements = 0;
  if ((argc > 2) && (verbose))
    NumGlobalElements = atoi(argv[2]) + 1;
  else if ((argc > 1) && (!verbose))
    NumGlobalElements = atoi(argv[1]) + 1;
  else
    NumGlobalElements = 101;


  // The number of unknowns must be at least equal to the
  // number of processors.
  if (NumGlobalElements < NumProc) {
    std::cout << "numGlobalBlocks = " << NumGlobalElements
    << " cannot be < number of processors = " << NumProc << std::endl;
    std::cout << "Test failed!" << std::endl;
    throw std::runtime_error("NOX Error");
  }

  // Create the interface between NOX and the application
  // This object is derived from NOX::Epetra::Interface
  Teuchos::RCP<Interface> interface =
    Teuchos::rcp(new Interface(NumGlobalElements, Comm));

  // Get the vector from the Problem
  Teuchos::RCP<Epetra_Vector> soln = interface->getSolution();
  Teuchos::RCP<NOX::Epetra::Vector> noxSoln =
    Teuchos::rcp(new NOX::Epetra::Vector(soln,
            NOX::Epetra::Vector::CreateView));

  // Set the PDE factor (for nonlinear forcing term).  This could be specified
  // via user input.
  interface->setPDEfactor(10000.0);

  // Set the initial guess
  soln->PutScalar(1.0);

  // Begin Nonlinear Solver ************************************

  // Create the top level parameter list
  Teuchos::RCP<Teuchos::ParameterList> nlParamsPtr =
    Teuchos::rcp(new Teuchos::ParameterList);
  Teuchos::ParameterList& nlParams = *(nlParamsPtr.get());

  // Set the nonlinear solver method
  nlParams.set("Nonlinear Solver", "Tensor Based");

  // Set the printing parameters in the "Printing" sublist
  Teuchos::ParameterList& printParams = nlParams.sublist("Printing");
  printParams.set("MyPID", MyPID);
  printParams.set("Output Precision", 3);
  printParams.set("Output Processor", 0);
  if (verbose)
    printParams.set("Output Information",
                    NOX::Utils::OuterIteration +
                    NOX::Utils::OuterIterationStatusTest +
                    NOX::Utils::InnerIteration +
                    NOX::Utils::LinearSolverDetails +
                    NOX::Utils::Parameters +
                    NOX::Utils::Details +
                    NOX::Utils::Warning +
                    NOX::Utils::Debug +
                    NOX::Utils::TestDetails +
                    NOX::Utils::Error);
  else
    printParams.set("Output Information", NOX::Utils::Error +
                                          NOX::Utils::TestDetails);

  // Create a print class for controlling output below
  NOX::Utils printing(printParams);

  // Sublist for line search
  Teuchos::ParameterList& searchParams = nlParams.sublist("Line Search");
  searchParams.set("Method", "Curvilinear");
  searchParams.sublist("Curvilinear").set("Lambda Selection", "Halving");
  searchParams.sublist("Curvilinear").set("Max Iters", 20);

  // Sublist for direction
  Teuchos::ParameterList& dirParams = nlParams.sublist("Direction");
  dirParams.set("Method", "Newton");
  Teuchos::ParameterList& newtonParams = dirParams.sublist("Newton");
  newtonParams.set("Forcing Term Method", "Constant");

  // Sublist for linear solver for the Newton method
  Teuchos::ParameterList& lsParams = newtonParams.sublist("Linear Solver");
  lsParams.set("Aztec Solver", "GMRES");
  lsParams.set("Max Iterations", 800);
  lsParams.set("Tolerance", 1e-4);

  // Various Preconditioner options
  //lsParams.set("Preconditioner", "None");
  //lsParams.set("Preconditioner", "AztecOO");
  lsParams.set("Preconditioner", "New Ifpack");
  lsParams.set("Preconditioner Reuse Policy", "Reuse");
  //lsParams.set("Preconditioner Reuse Policy", "Recompute");
  //lsParams.set("Preconditioner Reuse Policy", "Rebuild");
  lsParams.set("Max Age Of Prec", 5);

  // Let's force all status tests to do a full check
  nlParams.sublist("Solver Options").set("Status Test Check Type", "Complete");

  // Create all possible Epetra_Operators.
  // 1. User supplied (Epetra_RowMatrix)
  Teuchos::RCP<Epetra_RowMatrix> Analytic = interface->getJacobian();
  // 2. Matrix-Free (Epetra_Operator)
  Teuchos::RCP<NOX::Epetra::MatrixFree> MF =
    Teuchos::rcp(new NOX::Epetra::MatrixFree(printParams, interface,
                                             *noxSoln));
  // 3. Finite Difference (Epetra_RowMatrix)
  Teuchos::RCP<NOX::Epetra::FiniteDifference> FD =
    Teuchos::rcp(new NOX::Epetra::FiniteDifference(printParams, interface,
                                                   *soln));

  // Create the linear system
  Teuchos::RCP<NOX::Epetra::Interface::Required> iReq = interface;
  Teuchos::RCP<NOX::Epetra::Interface::Jacobian> iJac = MF;
  Teuchos::RCP<NOX::Epetra::Interface::Preconditioner> iPrec = FD;
  Teuchos::RCP<NOX::Epetra::LinearSystemAztecOO> linSys =
    Teuchos::rcp(new NOX::Epetra::LinearSystemAztecOO(printParams, lsParams,
                                                      //interface,
                                                      iJac, MF,
                                                      iPrec, FD,
                                                      *soln));

  // Create the Group
  NOX::Epetra::Vector initialGuess(soln, NOX::Epetra::Vector::CreateView);
  Teuchos::RCP<NOX::Epetra::Group> grpPtr =
    Teuchos::rcp(new NOX::Epetra::Group(printParams,
                                        iReq,
                                        initialGuess,
                                        linSys));
  NOX::Epetra::Group& grp = *grpPtr;

  // uncomment the following for loca supergroups
  //MF->setGroupForComputeF(*grpPtr);
  //FD->setGroupForComputeF(*grpPtr);

  // Create the convergence tests
  Teuchos::RCP<NOX::StatusTest::NormF> absresid =
    Teuchos::rcp(new NOX::StatusTest::NormF(1.0e-8));
  Teuchos::RCP<NOX::StatusTest::NormF> relresid =
    Teuchos::rcp(new NOX::StatusTest::NormF(grp, 1.0e-2));
  Teuchos::RCP<NOX::StatusTest::NormUpdate> update =
    Teuchos::rcp(new NOX::StatusTest::NormUpdate(1.0e-5));
  Teuchos::RCP<NOX::StatusTest::NormWRMS> wrms =
    Teuchos::rcp(new NOX::StatusTest::NormWRMS(1.0e-2, 1.0e-8));
  Teuchos::RCP<NOX::StatusTest::Combo> converged =
    Teuchos::rcp(new NOX::StatusTest::Combo(NOX::StatusTest::Combo::AND));
  converged->addStatusTest(absresid);
  converged->addStatusTest(relresid);
  converged->addStatusTest(wrms);
  converged->addStatusTest(update);
  Teuchos::RCP<NOX::StatusTest::MaxIters> maxiters =
    Teuchos::rcp(new NOX::StatusTest::MaxIters(20));
  Teuchos::RCP<NOX::StatusTest::FiniteValue> fv =
    Teuchos::rcp(new NOX::StatusTest::FiniteValue);
  Teuchos::RCP<NOX::StatusTest::Combo> combo =
    Teuchos::rcp(new NOX::StatusTest::Combo(NOX::StatusTest::Combo::OR));
  combo->addStatusTest(fv);
  combo->addStatusTest(converged);
  combo->addStatusTest(maxiters);

  // Create the solver
  Teuchos::RCP<NOX::Solver::Generic> solver =
    NOX::Solver::buildSolver(grpPtr, combo, nlParamsPtr);
  NOX::StatusTest::StatusType solvStatus = solver->solve();

  // End Nonlinear Solver **************************************

  // Get the Epetra_Vector with the final solution from the solver
  const NOX::Epetra::Group& finalGroup =
    dynamic_cast<const NOX::Epetra::Group&>(solver->getSolutionGroup());
  const Epetra_Vector& finalSolution =
    (dynamic_cast<const NOX::Epetra::Vector&>(finalGroup.getX())).
      getEpetraVector();

  // Output the parameter list
  if (verbose) {
    if (printing.isPrintType(NOX::Utils::Parameters)) {
      printing.out() << std::endl << "Final Parameters" << std::endl
      << "****************" << std::endl;
      solver->getList().print(printing.out());
      printing.out() << std::endl;
    }
  }

  // Print solution
  char file_name[25];
  FILE *ifp;
  int NumMyElements = soln->Map().NumMyElements();
  (void) sprintf(file_name, "output.%d",MyPID);
  ifp = fopen(file_name, "w");
  for (int i=0; i<NumMyElements; i++)
    fprintf(ifp, "%d  %E\n", soln->Map().MinMyGID()+i, finalSolution[i]);
  fclose(ifp);


  // Tests
  int status = 0; // Converged

  // 1. Convergence
  if (solvStatus != NOX::StatusTest::Converged) {
    status = 1;
    if (printing.isPrintType(NOX::Utils::Error))
      printing.out() << "Nonlinear solver failed to converge!" << std::endl;
  }
#ifndef HAVE_MPI
    // 2. Linear solve iterations (68) - SERIAL TEST ONLY!
    //    The number of linear iterations changes with # of procs.
    if (const_cast<Teuchos::ParameterList&>(solver->getList()).sublist("Direction").sublist("Newton").sublist("Linear Solver").sublist("Output").get("Total Number of Linear Iterations",0) != 68) {
      status = 2;
    }
#endif
    // 3. Nonlinear solve iterations (13)
    if (const_cast<Teuchos::ParameterList&>(solver->getList()).sublist("Output").get("Nonlinear Iterations", 0) != 13)
      status = 3;

    success = status==0;

    // Summarize test results
    if (success)
      printing.out() << "Test passed!" << std::endl;
    else
      printing.out() << "Test failed!" << std::endl;

    printing.out() << "Status = " << status << std::endl;
  }
  TEUCHOS_STANDARD_CATCH_STATEMENTS(verbose, std::cerr, success);

  return ( success ? EXIT_SUCCESS : EXIT_FAILURE );
}
