DOLFIN
DOLFIN C++ interface
BoostGraphColoring.h
1// Copyright (C) 2010 Garth N. Wells
2//
3// This file is part of DOLFIN.
4//
5// DOLFIN is free software: you can redistribute it and/or modify
6// it under the terms of the GNU Lesser General Public License as published by
7// the Free Software Foundation, either version 3 of the License, or
8// (at your option) any later version.
9//
10// DOLFIN is distributed in the hope that it will be useful,
11// but WITHOUT ANY WARRANTY; without even the implied warranty of
12// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13// GNU Lesser General Public License for more details.
14//
15// You should have received a copy of the GNU Lesser General Public License
16// along with DOLFIN. If not, see <http://www.gnu.org/licenses/>.
17//
18// First added: 2010-11-24
19// Last changed:
20
21#ifndef __DOLFIN_BOOST_GRAPH_INTERFACE_H
22#define __DOLFIN_BOOST_GRAPH_INTERFACE_H
23
24#include <iostream>
25#include <vector>
26
27#include <boost/graph/adjacency_list.hpp>
28#include <boost/graph/compressed_sparse_row_graph.hpp>
29#include <boost/graph/sequential_vertex_coloring.hpp>
30#include <dolfin/common/Timer.h>
31#include "Graph.h"
32
33namespace dolfin
34{
35
36 class Mesh;
37
39
41 {
42
43 public:
44
46 template<typename ColorType>
47 static std::size_t compute_local_vertex_coloring(const Graph& graph,
48 std::vector<ColorType>& colors)
49 {
50 Timer timer("Boost graph coloring (from dolfin::Graph)");
51
52 // Typedef for Boost compressed sparse row graph
53 typedef boost::compressed_sparse_row_graph<boost::directedS,
54 boost::property<boost::vertex_color_t, ColorType> > BoostGraph;
55
56 // Number of vertices
57 const std::size_t n = graph.size();
58
59 // Count number of edges
60 Graph::const_iterator vertex;
61 std::size_t num_edges = 0;
62 for (vertex = graph.begin(); vertex != graph.end(); ++vertex)
63 num_edges += vertex->size();
64
65 // Build list of graph edges
66 std::vector<std::pair<std::size_t, std::size_t> > edges;
67 edges.reserve(num_edges);
69 for (vertex = graph.begin(); vertex != graph.end(); ++vertex)
70 {
71 for (edge = vertex->begin(); edge != vertex->end(); ++edge)
72 {
73 const std::size_t vertex_index = vertex - graph.begin();
74 if (vertex_index != (std::size_t) *edge)
75 edges.push_back(std::make_pair(vertex_index, *edge));
76 }
77 }
78 // Build Boost graph
79 const BoostGraph g(boost::edges_are_unsorted_multi_pass,
80 edges.begin(), edges.end(), n);
81
82 // Resize vector to hold colors
83 colors.resize(n);
84
85 // Perform coloring
86 return compute_local_vertex_coloring(g, colors);
87 }
88
90 template<typename T, typename ColorType>
91 static std::size_t compute_local_vertex_coloring(const T& graph,
92 std::vector<ColorType>& colors)
93 {
94 Timer timer("Boost graph coloring");
95
96 // Number of vertices in graph
97 const std::size_t num_vertices = boost::num_vertices(graph);
98 dolfin_assert(num_vertices == colors.size());
99
100 typedef typename boost::graph_traits<T>::vertices_size_type
101 vert_size_type;
102 typedef typename boost::property_map<T,
103 boost::vertex_index_t>::const_type vert_index_map;
104
105 // Resize to hold colors
106 colors.resize(num_vertices);
107
108 // Color vertices
109 std::vector<vert_size_type> _colors(num_vertices);
110 boost::iterator_property_map<vert_size_type*, vert_index_map>
111 color(&_colors.front(), get(boost::vertex_index, graph));
112 const vert_size_type num_colors = sequential_vertex_coloring(graph,
113 color);
114
115 // Copy colors and return
116 std::copy(_colors.begin(), _colors.end(), colors.begin());
117 return num_colors;
118 }
119
120 };
121}
122
123#endif
This class colors a graph using the Boost Graph Library.
Definition: BoostGraphColoring.h:41
static std::size_t compute_local_vertex_coloring(const Graph &graph, std::vector< ColorType > &colors)
Compute vertex colors.
Definition: BoostGraphColoring.h:47
static std::size_t compute_local_vertex_coloring(const T &graph, std::vector< ColorType > &colors)
Compute vertex colors.
Definition: BoostGraphColoring.h:91
std::vector< T >::const_iterator const_iterator
Const iterator.
Definition: Set.h:43
Definition: Timer.h:48
Definition: adapt.h:30
std::vector< graph_set_type > Graph
Vector of unordered Sets.
Definition: Graph.h:39