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cxx_main.cpp
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41 
42 #include "Galeri_Maps.h"
43 #include "Galeri_CrsMatrices.h"
44 #include "Galeri_Utils.h"
45 #ifdef HAVE_MPI
46 #include "Epetra_MpiComm.h"
47 #include "mpi.h"
48 #else
49 #include "Epetra_SerialComm.h"
50 #endif
51 #include "Epetra_Map.h"
52 #include "Epetra_Vector.h"
53 #include "Epetra_CrsMatrix.h"
54 #include "Epetra_LinearProblem.h"
56 
57 using namespace Galeri;
58 
59 // =========== //
60 // main driver //
61 // =========== //
62 
63 int main(int argc, char* argv[])
64 {
65 #ifdef HAVE_MPI
66  MPI_Init(&argc, &argv);
67  Epetra_MpiComm Comm(MPI_COMM_WORLD);
68 #else
69  Epetra_SerialComm Comm;
70 #endif
71 
72  // Here we create the linear problem
73  //
74  // Matrix * LHS = RHS
75  //
76  // with Matrix arising from a 5-point formula discretization.
77 
78  Epetra_Map* Map = 0;
79  Epetra_RowMatrix* Matrix = 0;
80 
81  Teuchos::ParameterList GaleriList;
82  // dimension of the problem is nx x ny
83  GaleriList.set("nx", 10 * Comm.NumProc());
84  GaleriList.set("ny", 10);
85  // total number of processors is mx x my
86  GaleriList.set("mx", Comm.NumProc());
87  GaleriList.set("my", 1);
88 
89  try
90  {
91  Map = CreateMap("Cartesian2D", Comm, GaleriList);
92  Matrix = CreateCrsMatrix("Laplace2D", Map, GaleriList);
93  Epetra_Vector ExactSolution(*Map); ExactSolution.Random();
94  Epetra_Vector LHS(*Map); LHS.PutScalar(0.0);
95  Epetra_Vector RHS(*Map);
96 
97  Matrix->Multiply(false, ExactSolution, RHS);
98 
99  Epetra_LinearProblem Problem(Matrix, &LHS, &RHS);
100 
101  // at this point any object that understand Epetra_LinearProblem can be
102  // used, for example AztecOO, Amesos. IFPACK and ML can be used to define a
103  // preconditioner for Matrix. Here we use a simple solver, based on
104  // LAPACK, that is meant for simple testing only.
105 
106  Solve(Problem);
107 
108  // and we compute the norm of the true residual.
109  double ResidualNorm = ComputeNorm(Matrix, &LHS, &RHS);
110 
111  if (Comm.MyPID() == 0)
112  cout << ResidualNorm << endl;
113 
114  delete Map;
115  delete Matrix;
116  }
117  catch (Galeri::Exception& rhs)
118  {
119  if (Comm.MyPID() == 0)
120  rhs.Print();
121  exit(EXIT_FAILURE);
122  }
123 
124 #ifdef HAVE_MPI
125  MPI_Finalize();
126 #endif
127 
128  return(EXIT_SUCCESS);
129 }
ParameterList & set(std::string const &name, T const &value, std::string const &docString="", RCP< const ParameterEntryValidator > const &validator=null)
int MyPID() const
int NumProc() const
virtual int Multiply(bool TransA, const Epetra_MultiVector &X, Epetra_MultiVector &Y) const =0
int main(int argc, char *argv[])
Definition: CrsMatrix.cpp:61
int Solve(int, TYPE *, TYPE *, TYPE *)