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test/Copy/cxx_main.cpp
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4// EpetraExt: Epetra Extended - Linear Algebra Services Package
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41
42#include "Epetra_Map.h"
43#include "Epetra_Time.h"
44#include "Epetra_CrsMatrix.h"
45#include "Epetra_Vector.h"
47#include "Epetra_Flops.h"
48#ifdef EPETRA_MPI
49#include "Epetra_MpiComm.h"
50#include "mpi.h"
51#else
52#include "Epetra_SerialComm.h"
53#endif
54#include "Epetra_Version.h"
55#include "Trilinos_Util_CrsMatrixGallery.h"
57using namespace Trilinos_Util;
58
59// prototypes
60
61
62int main(int argc, char *argv[])
63{
64 int ierr = 0, i, forierr = 0;
65 bool debug = false;
66
67#ifdef EPETRA_MPI
68
69 // Initialize MPI
70
71 MPI_Init(&argc,&argv);
72 int size, rank; // Number of MPI processes, My process ID
73
74 MPI_Comm_size(MPI_COMM_WORLD, &size);
75 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
76 Epetra_MpiComm Comm( MPI_COMM_WORLD );
77
78#else
79
80 int size = 1; // Serial case (not using MPI)
81 int rank = 0;
83
84#endif
85
86 bool verbose = false;
87
88 // Check if we should print results to standard out
89 if (argc>1) if (argv[1][0]=='-' && argv[1][1]=='v') verbose = true;
90
91 // char tmp;
92 // if (rank==0) cout << "Press any key to continue..."<< endl;
93 // if (rank==0) cin >> tmp;
94 // Comm.Barrier();
95
96 int MyPID = Comm.MyPID();
97 int NumProc = Comm.NumProc();
98
99 if(verbose && MyPID==0)
100 cout << Epetra_Version() << endl << endl;
101
102 if (verbose) cout << "Processor "<<MyPID<<" of "<< NumProc
103 << " is alive."<<endl;
104
105// Generate Laplace matrix with 4 rows on each processor
106 CrsMatrixGallery laplace_2d("laplace_2d", Comm);
107 laplace_2d.Set("problem_size",Comm.NumProc()*Comm.NumProc()*4);
108 Epetra_CrsMatrix * laplace_2d_matrix = laplace_2d.GetMatrix();
109 if (verbose) cout << "Orig matrix = " << *laplace_2d_matrix << endl;
110 const Epetra_Map * origRowMap = laplace_2d.GetMap();
111 int * origGids = origRowMap->MyGlobalElements();
112
113 // Next generate a sub map of the original problem, taking every other GID.
114 Epetra_IntSerialDenseVector newRowMapGids(origRowMap->NumMyElements()/2 + 1);
115 int numNewRowGids = 0;
116 for (int i=0; i<origRowMap->NumMyElements(); i=i+2)
117 newRowMapGids[numNewRowGids++] = origGids[i];
118 Epetra_Map newRowMap(-1, numNewRowGids, newRowMapGids.Values(), 0, origRowMap->Comm());
119
120
121 // Use this new map to create a SubCopy transform that we can use on-demand to create submatrices
122 EpetraExt::CrsMatrix_SubCopy subMatrixTransform(newRowMap);
123
124 // Use the transform we just created to create our submatrix
125 Epetra_CrsMatrix & subA = subMatrixTransform(*laplace_2d_matrix);
126 if (verbose) cout << "Sub matrix (every other row/column) = " << subA << endl;
127
128
129 // Now test it using the fwd() method to see if changes in the original matrix are carried to the submatrix
130 (*laplace_2d_matrix)[0][0] = 12.0;
131 if (verbose) cout << "Orig matrix = " << *laplace_2d_matrix << endl;
132 subMatrixTransform.fwd();
133 assert(subA[0][0]==12.0);
134 if (verbose) cout << "Sub matrix (every other row/column) = " << subA << endl;
135
136
137 // Now change the submatrix and use the rvs() method to see if changes are carried to the original matrix
138 subA[0][0] = 24.0;
139 if (verbose) cout << "Sub matrix (every other row/column) = " << subA << endl;
140 subMatrixTransform.rvs();
141 assert((*laplace_2d_matrix)[0][0]==24.0);
142 if (verbose) cout << "Orig matrix = " << *laplace_2d_matrix << endl;
143
144 if (Comm.MyPID()==0) cout << "EpetraExt::CrsMatrix_SubCopy tests passed." << endl;
145#ifdef EPETRA_MPI
146 MPI_Finalize() ;
147#endif
148
149return 0;
150}
151
152
std::string Epetra_Version()
Generates a sub-block view of a Epetra_CrsMatrix.
int MyGlobalElements(int *MyGlobalElementList) const
const Epetra_Comm & Comm() const
int NumMyElements() const
int NumProc() const
int MyPID() const
int main(int argc, char *argv[])