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cxx_main.cpp
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1// @HEADER
2// ************************************************************************
3//
4// Galeri: Finite Element and Matrix Generation Package
5// Copyright (2006) ETHZ/Sandia Corporation
6//
7// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
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40// @HEADER
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"
55#include "Teuchos_ParameterList.hpp"
56
57using namespace Galeri;
58
59// =========== //
60// main driver //
61// =========== //
62
63int main(int argc, char* argv[])
64{
65#ifdef HAVE_MPI
66 MPI_Init(&argc, &argv);
67 Epetra_MpiComm Comm(MPI_COMM_WORLD);
68#else
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}
int NumProc() const
int MyPID() const
int PutScalar(double ScalarConstant)
virtual int Multiply(bool TransA, const Epetra_MultiVector &X, Epetra_MultiVector &Y) const=0
int main(int argc, char *argv[])
Definition: cxx_main.cpp:63