C++ AztecOO::SetUserMatrix方法代码示例

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;

  // The problem is defined on a 2D grid, global size is nx * nx.
  int nx = 30;
  Teuchos::ParameterList GaleriList;
  GaleriList.set("nx", nx);
  GaleriList.set("ny", nx * Comm.NumProc());
  GaleriList.set("mx", 1);
  GaleriList.set("my", Comm.NumProc());
  Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
  Teuchos::RefCountPtr<Epetra_CrsMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("Laplace2D", &*Map, GaleriList) );
  Teuchos::RefCountPtr<Epetra_MultiVector> LHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
  Teuchos::RefCountPtr<Epetra_MultiVector> RHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
  LHS->PutScalar(0.0); RHS->Random();

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

  // I wanna test funky values to be sure that they have the same
  // influence on the algorithms, both old and new
  int    LevelFill = 2;
  double DropTol = 0.3333;
  double Condest;
  
  Teuchos::RefCountPtr<Ifpack_CrsIct> ICT;
  ICT = Teuchos::rcp( new Ifpack_CrsIct(*A,DropTol,LevelFill) );
  ICT->SetAbsoluteThreshold(0.00123);
  ICT->SetRelativeThreshold(0.9876);
  // Init values from A
  ICT->InitValues(*A);
  // compute the factors
  ICT->Factor();
  // and now estimate the condition number
  ICT->Condest(false,Condest);
  
  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
  LHS->PutScalar(0.0);

  int Niters = 1200;

  AztecOO solver;
  solver.SetUserMatrix(&*A);
  solver.SetLHS(&*LHS);
  solver.SetRHS(&*RHS);
  solver.SetAztecOption(AZ_solver,AZ_cg);
  solver.SetPrecOperator(&*ICT);
  solver.SetAztecOption(AZ_output, 16); 
  solver.Iterate(Niters, 5.0e-5);

  int OldIters = solver.NumIters();

  // now rebuild the same preconditioner using ICT, we expect the same
  // number of iterations

  Ifpack Factory;
  Teuchos::RefCountPtr<Ifpack_Preconditioner> Prec = Teuchos::rcp( Factory.Create("IC", &*A) );

  Teuchos::ParameterList List;
  List.get("fact: level-of-fill", 2);
  List.get("fact: drop tolerance", 0.3333);
  List.get("fact: absolute threshold", 0.00123);
  List.get("fact: relative threshold", 0.9876);
  List.get("fact: relaxation value", 0.0);

  IFPACK_CHK_ERR(Prec->SetParameters(List));
  IFPACK_CHK_ERR(Prec->Compute());

  // Here we create an AztecOO object
  LHS->PutScalar(0.0);

  solver.SetUserMatrix(&*A);
  solver.SetLHS(&*LHS);
  solver.SetRHS(&*RHS);
  solver.SetAztecOption(AZ_solver,AZ_cg);
  solver.SetPrecOperator(&*Prec);
  solver.SetAztecOption(AZ_output, 16); 
  solver.Iterate(Niters, 5.0e-5);

//.........这里部分代码省略.........

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;
//.........这里部分代码省略.........

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

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

  // The problem is defined on a 2D grid, global size is nx * nx.
  int nx = 30;
  Teuchos::ParameterList GaleriList;
  GaleriList.set("nx", nx);
  GaleriList.set("ny", nx * Comm.NumProc());
  GaleriList.set("mx", 1);
  GaleriList.set("my", Comm.NumProc());
  Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
  Teuchos::RefCountPtr<Epetra_CrsMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("Laplace2D", &*Map, GaleriList) );
  Teuchos::RefCountPtr<Epetra_MultiVector> LHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
  Teuchos::RefCountPtr<Epetra_MultiVector> RHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
  LHS->PutScalar(0.0); RHS->Random();

  // ========================================= //
  // Compare IC preconditioners to no precond. //
  // ----------------------------------------- //

  const double tol = 1e-5;
  const int maxIter = 500;

  // Baseline: No preconditioning
  // Compute number of iterations, to compare to IC later.

  // Here we create an AztecOO object
  LHS->PutScalar(0.0);

  AztecOO solver;
  solver.SetUserMatrix(&*A);
  solver.SetLHS(&*LHS);
  solver.SetRHS(&*RHS);
  solver.SetAztecOption(AZ_solver,AZ_cg);
  //solver.SetPrecOperator(&*PrecDiag);
  solver.SetAztecOption(AZ_output, 16); 
  solver.Iterate(maxIter, tol);

  int Iters = solver.NumIters();
  //cout << "No preconditioner iterations: " << Iters << endl;

#if 0 
  // Not sure how to use Ifpack_CrsRick - leave out for now.
  //
  // I wanna test funky values to be sure that they have the same
  // influence on the algorithms, both old and new
  int    LevelFill = 2;
  double DropTol = 0.3333;
  double Condest;
  
  Teuchos::RefCountPtr<Ifpack_CrsRick> IC;
  Ifpack_IlukGraph mygraph (A->Graph(), 0, 0);
  IC = Teuchos::rcp( new Ifpack_CrsRick(*A, mygraph) );
  IC->SetAbsoluteThreshold(0.00123);
  IC->SetRelativeThreshold(0.9876);
  // Init values from A
  IC->InitValues(*A);
  // compute the factors
  IC->Factor();
  // and now estimate the condition number
  IC->Condest(false,Condest);
  
  if( Comm.MyPID() == 0 ) {
    cout << "Condition number estimate (level-of-fill = "
	 << LevelFill <<  ") = " << Condest << endl;
  }

  // Define label for printing out during the solve phase
  std::string label = "Ifpack_CrsRick Preconditioner: LevelFill = " + toString(LevelFill) + 
                                                 " Overlap = 0"; 
  IC->SetLabel(label.c_str());
  
  // Here we create an AztecOO object
  LHS->PutScalar(0.0);

  AztecOO solver;
  solver.SetUserMatrix(&*A);
  solver.SetLHS(&*LHS);
  solver.SetRHS(&*RHS);
  solver.SetAztecOption(AZ_solver,AZ_cg);
  solver.SetPrecOperator(&*IC);
  solver.SetAztecOption(AZ_output, 16); 
  solver.Iterate(maxIter, tol);

  int RickIters = solver.NumIters();
  //cout << "Ifpack_Rick iterations: " << RickIters << endl;

  // Compare to no preconditioning
  if (RickIters > Iters/2)
    IFPACK_CHK_ERR(-1);

#endif

  //////////////////////////////////////////////////////
//.........这里部分代码省略.........