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// Use of ML as a black-box smoothed aggregation preconditioner

#include "Didasko_ConfigDefs.h"
#if defined(HAVE_DIDASKO_EPETRA) && defined(HAVE_DIDASKO_ML) && defined(HAVE_DIDASKO_TRIUTILS) && defined(HAVE_DIDASKO_AZTECOO) && defined(HAVE_DIDASKO_TEUCHOS)

#include "Epetra_ConfigDefs.h"
#ifdef HAVE_MPI
#include "mpi.h"
#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_LinearProblem.h"
#include "Epetra_Time.h"
#include "AztecOO.h"

// includes required by ML
#include "ml_epetra_preconditioner.h"

#include "Trilinos_Util_CrsMatrixGallery.h"

using namespace Teuchos;
using namespace Trilinos_Util;

#include <iostream>

int main(int argc, char *argv[])
{

#ifdef EPETRA_MPI
  MPI_Init(&argc,&argv);
  Epetra_MpiComm Comm(MPI_COMM_WORLD);
#else
  Epetra_SerialComm Comm;
#endif

  Epetra_Time Time(Comm);

  // initialize an Gallery object
  CrsMatrixGallery Gallery("laplace_3d", Comm, false); // CJ TODO FIXME: change for Epetra64
  Gallery.Set("problem_size", 1000);

  // retrive pointers to matrix and linear problem
  Epetra_RowMatrix * A = Gallery.GetMatrix();
  Epetra_LinearProblem * Problem = Gallery.GetLinearProblem();

  // Construct a solver object for this problem
  AztecOO solver(*Problem);

  // create the preconditioner object and compute hierarchy
  ML_Epetra::MultiLevelPreconditioner * MLPrec =
    new ML_Epetra::MultiLevelPreconditioner(*A, true);

  // tell AztecOO to use this preconditioner, then solve
  solver.SetPrecOperator(MLPrec);

  solver.SetAztecOption(AZ_solver, AZ_gmres_condnum);
  solver.SetAztecOption(AZ_output, 32);
  solver.SetAztecOption(AZ_kspace, 160);

  int Niters = 500;
  solver.Iterate(Niters, 1e-12);

  // print out some information about the preconditioner
  if( Comm.MyPID() == 0 ) cout << MLPrec->GetOutputList();

  delete MLPrec;

  // compute the real residual

  double residual, diff;
  Gallery.ComputeResidual(&residual);
  Gallery.ComputeDiffBetweenStartingAndExactSolutions(&diff);

  if( Comm.MyPID()==0 ) {
    cout << "||b-Ax||_2 = " << residual << endl;
    cout << "||x_exact - x||_2 = " << diff << endl;
    cout << "Total Time = " << Time.ElapsedTime() << endl;
  }

  if (residual > 1e-5)
    exit(EXIT_FAILURE);
#ifdef EPETRA_MPI
  MPI_Finalize() ;
#endif
  return(EXIT_SUCCESS);
}
#else

#include <stdlib.h>
#include <stdio.h>
#ifdef HAVE_MPI
#include "mpi.h"
#endif

int main(int argc, char *argv[])
{
#ifdef HAVE_MPI
  MPI_Init(&argc,&argv);
#endif

  puts("Please configure Didasko with:\n"
      "--enable-epetra\n"
      "--enable-teuchos\n"
      "--enable-triutils\n"
      "--enable-aztecoo\n"
      "--enable-ml");

#ifdef HAVE_MPI
  MPI_Finalize();
#endif

  return(EXIT_SUCCESS);
}
#endif