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Ifpack_UserPartitioner.cpp
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
43#include "Ifpack_ConfigDefs.h"
44#include "Ifpack_Partitioner.h"
45#include "Ifpack_OverlappingPartitioner.h"
46#include "Ifpack_UserPartitioner.h"
47#include "Epetra_CrsGraph.h"
48
49//==============================================================================
51{
52
53 if (Map_ == 0)
54 IFPACK_CHK_ERR(-1);
55
56 if(keepSingletons_) {
57 // If we're keeping singletons, we need to count them and add a new part
58 // per singleton
59 int base_num_parts = NumLocalParts();
60 int curr_num_parts = base_num_parts;
61
62 for (int i = 0 ; i < NumMyRows() ; ++i) {
63 if(Map_[i] != -1)
64 Partition_[i] = Map_[i];
65 else {
66 Partition_[i] = curr_num_parts;
67 curr_num_parts++;
68 }
69 }
70
71 if(curr_num_parts != base_num_parts) {
72 NumLocalParts_ = curr_num_parts;
73 Parts_.resize(NumLocalParts());
74 }
75 }
76 else {
77 // copy the user's vector
78 for (int i = 0 ; i < NumMyRows() ; ++i) {
79 Partition_[i] = Map_[i];
80 }
81 }
82
83
84#if 0
85 // put together all partitions composed by 1 one vertex
86 // (if any)
87 std::vector<int> singletons(NumLocalParts());
88 for (unsigned int i = 0 ; i < singletons.size() ; ++i) {
89 singletons[i] = 0;
90 }
91
92
93 // may want to uncomment the following to ensure that no
94 // partitions are in fact singletons
95 for (int i = 0 ; i < NumMyRows() ; ++i) {
96 ++singletons[Partition_[i]];
97 }
98
99 int count = 0;
100 for (unsigned int i = 0 ; i < singletons.size() ; ++i) {
101 if (singletons[i] == 1)
102 ++count;
103 }
104
105 int index = -1;
106 for (int i = 0 ; i < NumMyRows() ; ++i) {
107 int j = Partition_[i];
108 if (singletons[j] == 1) {
109 if (index == -1)
110 index = j;
111 else
112 Partition_[i] = index;
113 }
114 }
115#endif
116
117 return(0);
118}
std::vector< std::vector< int > > Parts_
Parts_[i][j] is the ID of the j-th row contained in the (overlapping)
int NumLocalParts() const
Returns the number of computed local partitions.
int NumLocalParts_
Number of local subgraphs.
int NumMyRows() const
Returns the number of local rows.
std::vector< int > Partition_
Partition_[i] contains the ID of non-overlapping part it belongs to.
int ComputePartitions()
Computes the partitions. Returns 0 if successful.