Fix the rename script.
3 * This file is a part of LEMON, a generic C++ optimization library
5 * Copyright (C) 2003-2008
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
24 \todo Write a new Graphs page. I think it should be contain the Graph,
25 UGraph and BpUGraph concept. It should be describe the iterators and
26 the basic functions and the differences of the implementations.
28 The primary data structures of LEMON are the graph classes. They all
29 provide a node list - edge list interface, i.e. they have
30 functionalities to list the nodes and the edges of the graph as well
31 as incoming and outgoing edges of a given node.
33 Each graph should meet the \ref concepts::Graph "Graph" concept.
34 This concept does not make it possible to change the graph (i.e. it is
35 not possible to add or delete edges or nodes). Most of the graph
36 algorithms will run on these graphs.
39 In case of graphs meeting the full feature
40 \ref concepts::ErasableGraph "ErasableGraph" concept
41 you can also erase individual edges and nodes in arbitrary order.
43 The implemented graph structures are the following.
44 \li \ref ListGraph is the most versatile graph class. It meets
45 the \ref concepts::ErasableGraph "ErasableGraph" concept
46 and it also has some convenient extra features.
47 \li \ref SmartGraph is a more memory efficient version of \ref ListGraph.
48 The price of this is that it only meets the
49 \ref concepts::ExtendableGraph "ExtendableGraph" concept,
50 so you cannot delete individual edges or nodes.
51 \li \ref FullGraph "FullGraph"
52 implements a complete graph. It is a
53 \ref concepts::Graph "Graph", so you cannot
54 change the number of nodes once it is constructed. It is extremely memory
55 efficient: it uses constant amount of memory independently from the number of
56 the nodes of the graph. Of course, the size of the \ref maps-page "NodeMap"'s and
57 \ref maps-page "EdgeMap"'s will depend on the number of nodes.
59 \li \ref NodeSet "NodeSet" implements a graph with no edges. This class
60 can be used as a base class of \ref lemon::EdgeSet "EdgeSet".
61 \li \ref EdgeSet "EdgeSet" can be used to create a new graph on
62 the node set of another graph. The base graph can be an arbitrary graph and it
63 is possible to attach several \ref EdgeSet "EdgeSet"'s to a base graph.
65 \todo Don't we need SmartNodeSet and SmartEdgeSet?
66 \todo Some cross-refs are wrong.
68 The graph structures themselves can not store data attached
69 to the edges and nodes. However they all provide
70 \ref maps-page "map classes"
71 to dynamically attach data the to graph components.
73 The following program demonstrates the basic features of LEMON's graph
78 #include <lemon/list_graph.h>
80 using namespace lemon;
84 typedef ListGraph Graph;
87 ListGraph is one of LEMON's graph classes. It is based on linked lists,
88 therefore iterating throuh its edges and nodes is fast.
91 typedef Graph::Edge Edge;
92 typedef Graph::InEdgeIt InEdgeIt;
93 typedef Graph::OutEdgeIt OutEdgeIt;
94 typedef Graph::EdgeIt EdgeIt;
95 typedef Graph::Node Node;
96 typedef Graph::NodeIt NodeIt;
100 for (int i = 0; i < 3; i++)
103 for (NodeIt i(g); i!=INVALID; ++i)
104 for (NodeIt j(g); j!=INVALID; ++j)
105 if (i != j) g.addEdge(i, j);
108 After some convenient typedefs we create a graph and add three nodes to it.
109 Then we add edges to it to form a complete graph.
112 std::cout << "Nodes:";
113 for (NodeIt i(g); i!=INVALID; ++i)
114 std::cout << " " << g.id(i);
115 std::cout << std::endl;
118 Here we iterate through all nodes of the graph. We use a constructor of the
119 node iterator to initialize it to the first node. The operator++ is used to
120 step to the next node. Using operator++ on the iterator pointing to the last
121 node invalidates the iterator i.e. sets its value to
122 \ref INVALID. This is what we exploit in the stop condition.
124 The previous code fragment prints out the following:
131 std::cout << "Edges:";
132 for (EdgeIt i(g); i!=INVALID; ++i)
133 std::cout << " (" << g.id(g.source(i)) << "," << g.id(g.target(i)) << ")";
134 std::cout << std::endl;
138 Edges: (0,2) (1,2) (0,1) (2,1) (1,0) (2,0)
141 We can also iterate through all edges of the graph very similarly. The
143 \c source member functions can be used to access the endpoints of an edge.
146 NodeIt first_node(g);
148 std::cout << "Out-edges of node " << g.id(first_node) << ":";
149 for (OutEdgeIt i(g, first_node); i!=INVALID; ++i)
150 std::cout << " (" << g.id(g.source(i)) << "," << g.id(g.target(i)) << ")";
151 std::cout << std::endl;
153 std::cout << "In-edges of node " << g.id(first_node) << ":";
154 for (InEdgeIt i(g, first_node); i!=INVALID; ++i)
155 std::cout << " (" << g.id(g.source(i)) << "," << g.id(g.target(i)) << ")";
156 std::cout << std::endl;
160 Out-edges of node 2: (2,0) (2,1)
161 In-edges of node 2: (0,2) (1,2)
164 We can also iterate through the in and out-edges of a node. In the above
165 example we print out the in and out-edges of the first node of the graph.
168 Graph::EdgeMap<int> m(g);
170 for (EdgeIt e(g); e!=INVALID; ++e)
171 m.set(e, 10 - g.id(e));
173 std::cout << "Id Edge Value" << std::endl;
174 for (EdgeIt e(g); e!=INVALID; ++e)
175 std::cout << g.id(e) << " (" << g.id(g.source(e)) << "," << g.id(g.target(e))
176 << ") " << m[e] << std::endl;
189 As we mentioned above, graphs are not containers rather
190 incidence structures which are iterable in many ways. LEMON introduces
191 concepts that allow us to attach containers to graphs. These containers are
194 In the example above we create an EdgeMap which assigns an integer value to all
195 edges of the graph. We use the set member function of the map to write values
196 into the map and the operator[] to retrieve them.
198 Here we used the maps provided by the ListGraph class, but you can also write
199 your own maps. You can read more about using maps \ref maps-page "here".