-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathconncomp.cpp
More file actions
133 lines (109 loc) · 3.14 KB
/
conncomp.cpp
File metadata and controls
133 lines (109 loc) · 3.14 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/*
* This file is part of the GreasePad distribution (https://github.com/FraunhoferIOSB/GreasePad).
* Copyright (c) 2022-2025 Jochen Meidow, Fraunhofer IOSB
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include "conncomp.h"
#include <Eigen/Core>
#include <cassert>
namespace Graph {
ConnComp::ConnComp( const SparseMatrix<int, ColMajor> &BB)
{
// qDebug() << Q_FUNC_INFO;
assert( BB.rows()==BB.cols() );
// Q_ASSERT( BB.rows()==BB.cols() );
const Index V = BB.rows(); // number of vertices
m_visited.setConstant( V,false);
m_comp.setConstant( V,-1);
int num_connected_components = 0;
for ( Index v=0; v<V; v++ ) {
if ( !m_visited(v) ) {
dfs( BB, num_connected_components++, v );
}
}
}
VectorXi ConnComp::head( const Index n) const
{
assert( n>=0 );
if ( n==0) {
return VectorXi(0);
}
return m_comp.head(n);
}
VectorXi ConnComp::tail( const Index n) const
{
assert( n>=0 );
if ( n==0) {
return VectorXi(0);
}
return m_comp.tail(n);
}
/*! Label of i-th element */
int ConnComp::label( const Index i) const
{
assert( i>=0 && i<m_comp.size() ) ;
return m_comp(i);
}
VectorXi ConnComp::mapHead(const int cc, const Index n) const
{
// (1) Vector length: How many elements with value cc? .........
int sz=0;
for ( int s=0; s<n; s++ ) {
if ( m_comp(s)==cc ) {
sz++;
}
}
// (2) Linear indices of these elements ........................
VectorXi map_(sz);
for ( int k=0, s=0; s<n; s++ ) {
if ( m_comp(s)==cc ) {
map_( k++ ) = s;
}
}
return map_;
}
VectorXi ConnComp::mapTail(const int cc, const Index n) const
{
// (1) Vector length: How many elements with value cc? .........
int sz=0;
for ( Index s=m_comp.size()-n; s<m_comp.size(); s++ ) {
if ( m_comp(s)==cc ) {
sz++;
}
}
// (2) Linear indices of these elements ........................
VectorXi map_(sz);
Index const offset = m_comp.size() - n;
for ( int k=0, s=0; s<n; s++ ) {
if ( m_comp( s+offset )==cc ) {
map_( k++ ) = s;
}
}
return map_;
}
//! depth-first search
void ConnComp::dfs( const SparseMatrix<int,ColMajor> &CC,
const int c,
const Index v)
{
m_visited(v) = true;
m_comp(v) = c;
for ( SparseMatrix<int,ColMajor>::InnerIterator it(CC,v); it; ++it) {
if ( !m_visited(it.index()) ) {
dfs( CC, c, it.row() );
}
}
}
} // namespace Graph