1// Copyright 2005 The Trustees of Indiana University.
2
3// Use, modification and distribution is subject to the Boost Software
4// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt)
6
7// Authors: Douglas Gregor
8// Andrew Lumsdaine
9#ifndef BOOST_GRAPH_METIS_HPP
10#define BOOST_GRAPH_METIS_HPP
11
12#ifdef BOOST_GRAPH_METIS_NO_INLINE
13# define BOOST_GRAPH_METIS_INLINE_KEYWORD
14#else
15# define BOOST_GRAPH_METIS_INLINE_KEYWORD inline
16#endif
17
18#include <string>
19#include <iostream>
20#include <iterator>
21#include <utility>
22#include <sstream>
23#include <exception>
24#include <vector>
25#include <algorithm>
26
27namespace boost { namespace graph {
28
29class metis_exception : public std::exception {};
30class metis_input_exception : public metis_exception {};
31
32class metis_reader
33{
34 public:
35 typedef std::size_t vertices_size_type;
36 typedef std::size_t edges_size_type;
37 typedef double vertex_weight_type;
38 typedef double edge_weight_type;
39
40 class edge_iterator
41 {
42 public:
43 typedef std::input_iterator_tag iterator_category;
44 typedef std::pair<vertices_size_type, vertices_size_type> value_type;
45 typedef const value_type& reference;
46 typedef const value_type* pointer;
47 typedef std::ptrdiff_t difference_type;
48
49 private:
50 class postincrement_proxy
51 {
52 postincrement_proxy(const value_type& value) : value(value) { }
53
54 public:
55 reference operator*() const { return value; }
56
57 private:
58 value_type value;
59 friend class edge_iterator;
60 };
61
62 public:
63 edge_iterator& operator++();
64 postincrement_proxy operator++(int);
65
66 reference operator*() const { return self->edge; }
67 pointer operator->() const { return &self->edge; }
68
69 // Default copy constructor and assignment operator are okay
70
71 private:
72 edge_iterator(metis_reader* self);
73 void advance(bool skip_initial_read);
74
75 metis_reader* self;
76
77 friend class metis_reader;
78 friend bool operator==(edge_iterator, edge_iterator);
79 friend bool operator!=(edge_iterator, edge_iterator);
80 };
81 friend class edge_iterator;
82
83 class edge_weight_iterator
84 {
85 public:
86 typedef std::input_iterator_tag iterator_category;
87 typedef edge_weight_type value_type;
88 typedef const value_type& reference;
89 typedef const value_type* pointer;
90
91 // Default copy constructor and assignment operator are okay
92
93 reference operator*() const { return self->edge_weight; }
94 pointer operator->() const { return &self->edge_weight; }
95
96 edge_weight_iterator& operator++() { return *this; }
97 edge_weight_iterator operator++(int) { return *this; }
98
99 private:
100 edge_weight_iterator(metis_reader* self) : self(self) { }
101
102 metis_reader* self;
103
104 friend class metis_reader;
105 };
106
107 metis_reader(std::istream& in) : in(in), edge_weight(1.0) { start(); }
108
109 edge_iterator begin();
110 edge_iterator end();
111 edge_weight_iterator weight_begin();
112
113 vertices_size_type num_vertices() const { return n_vertices; }
114 edges_size_type num_edges() const { return n_edges; }
115
116 std::size_t num_vertex_weights() const { return n_vertex_weights; }
117
118 vertex_weight_type vertex_weight(vertices_size_type v, std::size_t n)
119 { return vertex_weights[v*num_vertex_weights() + n]; }
120
121 bool has_edge_weights() const { return edge_weights; }
122
123 private:
124 void start();
125
126 // Configuration information
127 std::istream& in;
128
129 // Information about the current METIS file
130 vertices_size_type n_vertices;
131 edges_size_type n_edges;
132 std::size_t n_vertex_weights;
133 bool edge_weights;
134
135 // Information about the current edge/vertex
136 std::istringstream line_in;
137 std::pair<vertices_size_type, vertices_size_type> edge;
138 std::vector<vertex_weight_type> vertex_weights;
139 edge_weight_type edge_weight;
140
141 friend bool operator==(edge_iterator, edge_iterator);
142 friend bool operator!=(edge_iterator, edge_iterator);
143};
144
145class metis_distribution
146{
147 public:
148 typedef int process_id_type;
149 typedef std::size_t size_type;
150 typedef std::vector<process_id_type>::iterator iterator;
151
152 metis_distribution(std::istream& in, process_id_type my_id);
153
154 size_type block_size(process_id_type id, size_type) const;
155 process_id_type operator()(size_type n) const { return vertices[n]; }
156 size_type local(size_type n) const;
157 size_type global(size_type n) const { return global(id: my_id, n); }
158 size_type global(process_id_type id, size_type n) const;
159
160 iterator begin() { return vertices.begin(); }
161 iterator end() { return vertices.end(); }
162
163 private:
164 std::istream& in;
165 process_id_type my_id;
166 std::vector<process_id_type> vertices;
167};
168
169#if !defined(BOOST_GRAPH_METIS_NO_INLINE) || defined(BOOST_GRAPH_METIS_SOURCE)
170BOOST_GRAPH_METIS_INLINE_KEYWORD
171bool operator==(metis_reader::edge_iterator x, metis_reader::edge_iterator y)
172{
173 return (x.self == y.self
174 || (x.self && x.self->edge.first == x.self->num_vertices())
175 || (y.self && y.self->edge.first == y.self->num_vertices()));
176}
177
178BOOST_GRAPH_METIS_INLINE_KEYWORD
179bool operator!=(metis_reader::edge_iterator x, metis_reader::edge_iterator y)
180{
181 return !(x == y);
182}
183
184BOOST_GRAPH_METIS_INLINE_KEYWORD
185metis_reader::edge_iterator::edge_iterator(metis_reader* self)
186 : self(self)
187{
188 if (self) advance(skip_initial_read: true);
189}
190
191BOOST_GRAPH_METIS_INLINE_KEYWORD
192metis_reader::edge_iterator& metis_reader::edge_iterator::operator++()
193{
194 advance(skip_initial_read: false);
195 return *this;
196}
197
198BOOST_GRAPH_METIS_INLINE_KEYWORD
199void metis_reader::edge_iterator::advance(bool skip_initial_read)
200{
201 do {
202
203 if (!skip_initial_read) {
204 // Try to read the next edge
205 if (self->line_in >> std::ws >> self->edge.second) {
206 --self->edge.second;
207 if (self->has_edge_weights()) {
208 if (!(self->line_in >> self->edge_weight))
209 boost::throw_exception(e: metis_input_exception());
210 }
211 return;
212 }
213
214 // Check if we're done
215 ++self->edge.first;
216 if (self->edge.first == self->num_vertices())
217 return;
218 }
219
220 // Find the next line
221 std::string line;
222 while (getline(is&: self->in, str&: line) && !line.empty() && line[0] == '%') {
223 /* Keep reading lines in the loop header... */
224 }
225 if (!self->in) boost::throw_exception(e: metis_input_exception());
226 self->line_in.str(s: line);
227 self->line_in.clear();
228
229 // Read the next line
230 std::size_t weights_left = self->n_vertex_weights;
231 vertex_weight_type weight;
232 while (weights_left > 0) {
233 if (self->line_in >> weight) self->vertex_weights.push_back(x: weight);
234 else boost::throw_exception(e: metis_input_exception());
235 --weights_left;
236 }
237
238 // Successive iterations will pick up edges for this vertex.
239 skip_initial_read = false;
240 } while (true);
241}
242
243BOOST_GRAPH_METIS_INLINE_KEYWORD
244metis_reader::edge_iterator::postincrement_proxy
245metis_reader::edge_iterator::operator++(int)
246{
247 postincrement_proxy result(**this);
248 ++(*this);
249 return result;
250}
251
252BOOST_GRAPH_METIS_INLINE_KEYWORD
253metis_reader::edge_iterator metis_reader::begin()
254{
255 if (edge.first != 0) start();
256 return edge_iterator(this);
257}
258
259BOOST_GRAPH_METIS_INLINE_KEYWORD
260metis_reader::edge_iterator metis_reader::end()
261{
262 return edge_iterator(0);
263}
264
265BOOST_GRAPH_METIS_INLINE_KEYWORD
266metis_reader::edge_weight_iterator metis_reader::weight_begin()
267{
268 return edge_weight_iterator(this);
269}
270
271BOOST_GRAPH_METIS_INLINE_KEYWORD
272void metis_reader::start()
273{
274 in.seekg(0, std::ios::beg);
275 std::string line;
276 while (getline(is&: in, str&: line) && !line.empty() && line[0] == '%') {
277 /* Keep getting lines in loop header. */
278 }
279
280 if (!in || line.empty()) boost::throw_exception(e: metis_input_exception());
281
282 // Determine number of vertices and edges in the graph
283 line_in.str(s: line);
284 if (!(line_in >> n_vertices >> n_edges)) boost::throw_exception(e: metis_input_exception());
285
286 // Determine whether vertex or edge weights are included in the graph
287 int fmt = 0;
288 line_in >> fmt;
289 n_vertex_weights = fmt / 10;
290 edge_weights = (fmt % 10 == 1);
291
292 // Determine how many (if any!) vertex weights are included
293 if (n_vertex_weights) line_in >> n_vertex_weights;
294
295 // Setup the iteration data structures
296 edge_weight = 1.0;
297 edge.first = 0;
298 edge.second = 0;
299 vertex_weights.reserve(n: n_vertex_weights * num_vertices());
300}
301
302metis_distribution::metis_distribution(std::istream& in, process_id_type my_id)
303 : in(in), my_id(my_id),
304 vertices(std::istream_iterator<process_id_type>(in),
305 std::istream_iterator<process_id_type>())
306{
307}
308
309
310metis_distribution::size_type
311metis_distribution::block_size(process_id_type id, size_type) const
312{
313 return std::count(first: vertices.begin(), last: vertices.end(), value: id);
314}
315
316metis_distribution::size_type metis_distribution::local(size_type n) const
317{
318 return std::count(first: vertices.begin(), last: vertices.begin() + n, value: vertices[n]);
319}
320
321metis_distribution::size_type
322metis_distribution::global(process_id_type id, size_type n) const
323{
324 std::vector<process_id_type>::const_iterator i = vertices.begin();
325 while (*i != id) ++i;
326
327 while (n > 0) {
328 do { ++i; } while (*i != id);
329 --n;
330 }
331
332 return i - vertices.begin();
333}
334
335#endif
336
337} } // end namespace boost::graph
338
339#endif // BOOST_GRAPH_METIS_HPP
340

source code of boost/boost/graph/metis.hpp