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// Using IFPACK factorizations as Aztec's preconditioners
//
// NOTE: this example implemenets minor modifications to one of the
// examples included in the AztecOO package. Please give a look
// to file ${TRILINOS_HOME}/packages/aztecoo/examples/IfpackAztecOO/cxx_main.cpp
// for more details.

#include "Didasko_ConfigDefs.h"
#if defined(HAVE_DIDASKO_EPETRA) && defined(HAVE_DIDASKO_IFPACK) && defined(HAVE_DIDASKO_AZTECOO)

#include "Epetra_ConfigDefs.h"
#ifdef HAVE_MPI
#include "mpi.h"
#include "Epetra_MpiComm.h"
#else
#include "Epetra_SerialComm.h"
#endif
#include "Epetra_Comm.h"
#include "Epetra_Map.h"
#include "Epetra_Time.h"
#include "Epetra_BlockMap.h"
#include "Epetra_MultiVector.h"
#include "Epetra_Vector.h"
#include "Epetra_Export.h"
#include "AztecOO.h"
#include "Trilinos_Util.h"
#include "Epetra_VbrMatrix.h"
#include "Epetra_CrsMatrix.h"
#include "Ifpack_CrsIct.h"

// function for fancy output

string toString(const int& x) {
  char s[100];
  sprintf(s, "%d", x);
  return string(s);
}

string toString(const double& x) {
  char s[100];
  sprintf(s, "%g", x);
  return string(s);
}

// main driver

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

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

  int MyPID = Comm.MyPID();
  bool verbose = false;
  if (MyPID==0) verbose = true;

  // matrix downloaded from MatrixMarket
  char FileName[] = "../HBMatrices/fidap005.rua";

  Epetra_Map * readMap; // Pointers because of Trilinos_Util_ReadHb2Epetra
  Epetra_CrsMatrix * readA;
  Epetra_Vector * readx;
  Epetra_Vector * readb;
  Epetra_Vector * readxexact;

  // Call routine to read in HB problem
  Trilinos_Util_ReadHb2Epetra(FileName, Comm, readMap, readA, readx,
      readb, readxexact);

  int NumGlobalElements = readMap->NumGlobalElements();

  // Create uniform distributed map
  Epetra_Map map(NumGlobalElements, 0, Comm);

  // Create Exporter to distribute read-in matrix and vectors

  Epetra_Export exporter(*readMap, map);
  Epetra_CrsMatrix A(Copy, map, 0);
  Epetra_Vector x(map);
  Epetra_Vector b(map);
  Epetra_Vector xexact(map);

  Epetra_Time FillTimer(Comm);
  A.Export(*readA, exporter, Add);
  x.Export(*readx, exporter, Add);
  b.Export(*readb, exporter, Add);
  xexact.Export(*readxexact, exporter, Add);

  A.FillComplete();

  delete readA;
  delete readx;
  delete readb;
  delete readxexact;
  delete readMap;

  // ============================ //
  // Construct ILU preconditioner //
  // ---------------------------- //

  //  modify those parameters
  int    LevelFill = 1;
  double DropTol = 0.0;
  double Condest;

  Ifpack_CrsIct * ICT = NULL;
  ICT = new Ifpack_CrsIct(A,DropTol,LevelFill);
  // Init values from A
  ICT->InitValues(A);
  // compute the factors
  ICT->Factor();
  // and now estimate the condition number
  ICT->Condest(false,Condest);

  cout << Condest << endl;

  if( Comm.MyPID() == 0 ) {
    cout << "Condition number estimate (level-of-fill = "
      << LevelFill <<  ") = " << Condest << endl;
  }

  // Define label for printing out during the solve phase
  string label = "Ifpack_CrsIct Preconditioner: LevelFill = " + toString(LevelFill) +
    " Overlap = 0";
  ICT->SetLabel(label.c_str());

  // Here we create an AztecOO object
  AztecOO solver;
  solver.SetUserMatrix(&A);
  solver.SetLHS(&x);
  solver.SetRHS(&b);
  solver.SetAztecOption(AZ_solver,AZ_cg);

  // Here we set the IFPACK preconditioner and specify few parameters

  solver.SetPrecOperator(ICT);

  int Niters = 1200;
  solver.SetAztecOption(AZ_kspace, Niters);
  solver.SetAztecOption(AZ_output, 20);
  solver.Iterate(Niters, 5.0e-5);

  if (ICT!=0) delete ICT;

#ifdef HAVE_MPI
  MPI_Finalize() ;
#endif

  return 0 ;
}

#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:");
  puts("--enable-epetra");
  puts("--enable-ifpack");
  puts("--enable-aztecoo");

#ifdef HAVE_MPI
  MPI_Finalize();
#endif
  return 0;
}
#endif