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Ifpack_ex_Reordering.cpp
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1//@HEADER
2// ***********************************************************************
3//
4// Ifpack: Object-Oriented Algebraic Preconditioner Package
5// Copyright (2002) Sandia Corporation
6//
7// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
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41
42#include "Ifpack_ConfigDefs.h"
43#ifdef HAVE_MPI
44#include "Epetra_MpiComm.h"
45#else
46#include "Epetra_SerialComm.h"
47#endif
48#include "Epetra_Map.h"
49#include "Epetra_CrsMatrix.h"
50#include "Ifpack_Reordering.h"
53#include "Ifpack_Utils.h"
54#include "Teuchos_RefCountPtr.hpp"
55
56//==============================================================================
57int main(int argc, char *argv[])
58{
59 using std::cout;
60 using std::endl;
61
62#ifdef HAVE_MPI
63 MPI_Init(&argc,&argv);
64 Epetra_MpiComm Comm(MPI_COMM_WORLD);
65#else
67#endif
68
69 // only one process
70 if (Comm.NumProc() != 1) {
71#ifdef HAVE_MPI
72 MPI_Finalize();
73#endif
74 if (Comm.MyPID() == 0)
75 cout << "Please run this test with one process only" << endl;
76 // return success not to break the tests
77 exit(EXIT_SUCCESS);
78 }
79
80 // ======================================================== //
81 // now create the famous "upper arrow" matrix, which //
82 // should be reordered as a "lower arrow". Sparsity pattern //
83 // will be printed on screen. //
84 // ======================================================== //
85
86 int NumPoints = 16;
87
88#if !defined(EPETRA_NO_32BIT_GLOBAL_INDICES) || !defined(EPETRA_NO_64BIT_GLOBAL_INDICES)
89 Epetra_Map Map(-1,NumPoints,0,Comm);
90#else
91 Epetra_Map Map;
92#endif
93
94 std::vector<int> Indices(NumPoints);
95 std::vector<double> Values(NumPoints);
96
97 Teuchos::RefCountPtr<Epetra_CrsMatrix> A = Teuchos::rcp( new Epetra_CrsMatrix(Copy,Map,0) );
98 for (int i = 0 ; i < NumPoints ; ++i) {
99
100 int NumEntries;
101 if (i == 0) {
102 NumEntries = NumPoints;
103 for (int j = 0 ; j < NumPoints ; ++j) {
104 Indices[j] = j;
105 Values[j] = 1.0;
106 }
107 }
108 else {
109 NumEntries = 2;
110 Indices[0] = 0;
111 Indices[1] = i;
112 Values[0] = 1.0;
113 Values[1] = 1.0;
114 }
115
116#if !defined(EPETRA_NO_32BIT_GLOBAL_INDICES) || !defined(EPETRA_NO_64BIT_GLOBAL_INDICES)
117 A->InsertGlobalValues(i, NumEntries, &Values[0], &Indices[0]);
118#endif
119 }
120
121 A->FillComplete();
122
123 // print the sparsity to file, postscript format
125
126 // create the reordering...
127 Teuchos::RefCountPtr<Ifpack_RCMReordering> Reorder = Teuchos::rcp( new Ifpack_RCMReordering() );
128 // and compute is on A
129 IFPACK_CHK_ERR(Reorder->Compute(*A));
130
131 // cout information
132 cout << *Reorder;
133
134 // create a reordered matrix
135 Ifpack_ReorderFilter ReordA(A, Reorder);
136
137 // print the sparsity to file, postscript format
139
140#ifdef HAVE_MPI
141 MPI_Finalize();
142#endif
143 return(EXIT_SUCCESS);
144
145}
Copy
#define IFPACK_CHK_ERR(ifpack_err)
int main(int argc, char *argv[])
int NumProc() const
int MyPID() const
Ifpack_RCMReordering: reverse Cuthill-McKee reordering.
Ifpack_ReorderFilter: a class for light-weight reorder of local rows and columns of an Epetra_RowMatr...