test/OverlappingRowMatrix/cxx_main.cpp

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//       Ifpack: Object-Oriented Algebraic Preconditioner Package
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#include "Ifpack_ConfigDefs.h"

#ifdef HAVE_MPI
#include "Epetra_MpiComm.h"
#else
#include "Epetra_SerialComm.h"
#endif
#include "Epetra_CrsMatrix.h"
#include "Epetra_Vector.h"
#include "Epetra_LinearProblem.h"
#include "Epetra_Map.h"
#include "Epetra_Import.h"
#include "Epetra_Time.h"
#include "Galeri_Maps.h"
#include "Galeri_CrsMatrices.h"
#include "Teuchos_ParameterList.hpp"
#include "Teuchos_RCP.hpp"
#include "Ifpack_OverlappingRowMatrix.h"
#include "Ifpack_LocalFilter.h"
#include "Ifpack_Utils.h"
#include <sstream>
#include <stdexcept>

int main(int argc, char *argv[])
{
#ifdef HAVE_MPI
  MPI_Init(&argc,&argv);
  Epetra_MpiComm Comm( MPI_COMM_WORLD );
#else
  Epetra_SerialComm Comm;
#endif

  if (Comm.NumProc() == 1)
  {
#ifdef HAVE_MPI
    MPI_Finalize();
#endif
    cout << "Test `TestOverlappingRowMatrix.exe' passed!" << endl;
    exit(EXIT_SUCCESS);
  }

  Teuchos::ParameterList GaleriList;
  int nx = 100; 
  GaleriList.set("n", nx * nx);
  GaleriList.set("nx", nx);
  GaleriList.set("ny", nx);
  Teuchos::RCP<Epetra_Map> Map
    (Galeri::CreateMap ("Linear", Comm, GaleriList));
  Teuchos::RCP<Epetra_CrsMatrix> A
    (Galeri::CreateCrsMatrix ("Laplace2D", Map.getRawPtr (), GaleriList));

  int OverlapLevel = 5;
  Epetra_Time Time(Comm);

  // ======================================== //
  // Build the overlapping matrix using class //
  // Ifpack_OverlappingRowMatrix.             //
  // ======================================== //
 
  Time.ResetStartTime();
  Ifpack_OverlappingRowMatrix B(A,OverlapLevel);
  if (Comm.MyPID() == 0)
    cout << "Time to create B = " << Time.ElapsedTime() << endl;

  int NumGlobalRowsB = B.NumGlobalRows();
  int NumGlobalNonzerosB = B.NumGlobalNonzeros();

  Epetra_Vector X(A->RowMatrixRowMap());
  Epetra_Vector Y(A->RowMatrixRowMap());
  for (int i = 0 ; i < A->NumMyRows() ; ++i) 
    X[i] = 1.0* A->RowMatrixRowMap().GID(i);
  Y.PutScalar(0.0);

  Epetra_Vector ExtX_B(B.RowMatrixRowMap());
  Epetra_Vector ExtY_B(B.RowMatrixRowMap());
  ExtY_B.PutScalar(0.0);

  IFPACK_CHK_ERR(B.ImportMultiVector(X,ExtX_B));
  IFPACK_CHK_ERR(B.Multiply(false,ExtX_B,ExtY_B));
  IFPACK_CHK_ERR(B.ExportMultiVector(ExtY_B,Y,Add));

  double Norm_B;
  Y.Norm2(&Norm_B);
  if (Comm.MyPID() == 0)
    cout << "Norm of Y using B = " << Norm_B << endl;
  
  // ================================================== //
  //Build the overlapping matrix as an Epetra_CrsMatrix //
  // ================================================== //

  Time.ResetStartTime();
  Teuchos::RCP<Epetra_CrsMatrix> C(Ifpack_CreateOverlappingCrsMatrix(&*A,OverlapLevel));
  if (Comm.MyPID() == 0)
    cout << "Time to create C = " << Time.ElapsedTime() << endl;

  // simple checks on global quantities
  int NumGlobalRowsC = C->NumGlobalRows();
  int NumGlobalNonzerosC = C->NumGlobalNonzeros();

  if (NumGlobalRowsB != NumGlobalRowsC) {
    std::ostringstream os;
    os << "NumGlobalRowsB = " << NumGlobalRowsB
       << " != NumGlobalRowsC = " << NumGlobalRowsC
       << "." << std::endl;
    throw std::logic_error (os.str ());
  }
  if (NumGlobalNonzerosB != NumGlobalNonzerosC) {
    std::ostringstream os;
    os << "NumGlobalNonzerosB = " << NumGlobalNonzerosB
       << " != NumGlobalNonzerosC = " << NumGlobalNonzerosC
       << "." << std::endl;
    throw std::logic_error (os.str ());
  }

  Epetra_Vector ExtX_C(C->RowMatrixRowMap());
  Epetra_Vector ExtY_C(C->RowMatrixRowMap());
  ExtY_C.PutScalar(0.0);
  Y.PutScalar(0.0);

  IFPACK_CHK_ERR(C->Multiply(false,X,Y));

  double Norm_C;
  Y.Norm2(&Norm_C);
  if (Comm.MyPID() == 0)
    cout << "Norm of Y using C = " << Norm_C << endl;

  if (IFPACK_ABS(Norm_B - Norm_C) > 1e-5)
    IFPACK_CHK_ERR(-1);

  // ======================= //
  // now localize the matrix //
  // ======================= //

  Ifpack_LocalFilter D(Teuchos::rcp(&B, false));

#ifdef HAVE_MPI
  MPI_Finalize() ; 
#endif

  if (Comm.MyPID() == 0)
    cout << "Test `TestOverlappingRowMatrix.exe' passed!" << endl;

  return(EXIT_SUCCESS);
}