Turn off 32 bit only tests, cont'd.
5 \page lemon_file_format LEMON Graph File Format
7 The standard graph IO enables one to store graphs and additional maps
8 (i.e. functions on the nodes or edges) in a flexible and efficient way.
9 Before you read this page you should be familiar with LEMON
10 \ref graphs "graphs" and \ref maps-page "maps".
12 \section format The general file format
14 The file contains sections in the following order:
22 Some of these sections can be omitted, but you will basicly need the nodeset
23 section (unless your graph has no nodes at all) and the edgeset section
24 (unless your graph has no edges at all).
26 The nodeset section describes the nodes of your graph: it identifies the nodes
27 and gives the maps defined on them, if any. It starts with the
32 The next line contains the names of the nodemaps, separated by whitespaces. Each
33 following line describes a node in the graph: it contains the values of the
34 maps in the right order. The map named "label" should contain unique values
35 because it is regarded as a label map. These labels need not be numbers but they
36 must identify the nodes uniquely for later reference. For example:
40 label x-coord y-coord color
46 The edgeset section is very similar to the nodeset section, it has
47 the same coloumn oriented structure. It starts with the line
51 The next line contains the whitespace separated list of names of the edge
52 maps. Each of the next lines describes one edge. The first two elements in
53 the line are the labels of the source and target (or tail and head) nodes of the
54 edge as they occur in the label node map of the nodeset section. You can also
55 have an optional label map on the edges for later reference (which has to be
66 The \e nodes section contains <em>labeled (distinguished) nodes</em>
67 (i.e. nodes having a special
68 label on them). The section starts with
72 Each of the next lines contains a label for a node in the graph
73 and then the label as described in the \e nodeset section.
81 The last section describes the <em>labeled (distinguished) edges</em>
82 (i.e. edges having a special label on them). It starts with \c \@edges
83 and then each line contains the name of the edge and the label.
91 The file may contain empty lines and comment lines. The comment lines
92 start with an \c # character.
94 The attributes section can handle some information about the graph. It
95 contains key-value pairs in each line (a key and the mapped value to key). The
96 key should be a string without whitespaces, the value can be of various types.
100 title "Four colored planar graph"
101 author "Balazs DEZSO"
102 copyright "Lemon Library"
106 Finally, the file should be closed with \c \@end line.
109 \section use Using graph input-output
112 The graph input and output is based on <em> reading and writing
113 commands</em>. The user gives reading and writing commands to the reader or
114 writer class, then he calls the \c run() method that executes all the given
117 \subsection write Writing a graph
119 The \ref lemon::GraphWriter "GraphWriter" template class
120 provides the graph output. To write a graph
121 you should first give writing commands to the writer. You can declare
122 writing command as \c NodeMap or \c EdgeMap writing and labeled Node and
126 GraphWriter<ListGraph> writer(std::cout, graph);
129 The \ref lemon::GraphWriter::writeNodeMap() "writeNodeMap()"
130 function declares a \c NodeMap writing command in the
131 \ref lemon::GraphWriter "GraphWriter".
132 You should give a name to the map and the map
133 object as parameters. The NodeMap writing command with name "label" should write a
134 unique map because it will be regarded as a label map.
136 \see IdMap, DescriptorMap
139 IdMap<ListGraph, Node> nodeLabelMap;
140 writer.writeNodeMap("label", nodeLabelMap);
142 writer.writeNodeMap("x-coord", xCoordMap);
143 writer.writeNodeMap("y-coord", yCoordMap);
144 writer.writeNodeMap("color", colorMap);
147 With the \ref lemon::GraphWriter::writeEdgeMap() "writeEdgeMap()"
148 member function you can give an edge map
149 writing command similar to the NodeMaps.
151 \see IdMap, DescriptorMap
154 DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > edgeDescMap(graph);
155 writer.writeEdgeMap("descriptor", edgeDescMap);
157 writer.writeEdgeMap("weight", weightMap);
158 writer.writeEdgeMap("note", noteMap);
161 With \ref lemon::GraphWriter::writeNode() "writeNode()"
162 and \ref lemon::GraphWriter::writeEdge() "writeEdge()"
163 functions you can designate Nodes and
164 Edges in the graph. For example, you can write out the source and target node
165 of a maximum flow instance.
168 writer.writeNode("source", sourceNode);
169 writer.writeNode("target", targetNode);
171 writer.writeEdge("observed", edge);
174 With \ref lemon::GraphWriter::writeAttribute() "writeAttribute()"
175 function you can write an attribute to the file.
178 writer.writeAttribute("author", "Balazs DEZSO");
179 writer.writeAttribute("version", 12);
182 After you give all write commands you must call the
183 \ref lemon::GraphWriter::run() "run()" member
184 function, which executes all the writing commands.
190 \subsection reading Reading a graph
192 The file to be read may contain several maps and labeled nodes or edges.
193 If you read a graph you need not read all the maps and items just those
194 that you need. The interface of the \ref lemon::GraphReader "GraphReader"
196 the \ref lemon::GraphWriter "GraphWriter"
197 but the reading method does not depend on the order of the
200 The reader object assumes that each not read value does not contain
201 whitespaces, therefore it has some extra possibilities to control how
202 it should skip the values when the string representation contains spaces.
205 GraphReader<ListGraph> reader(std::cin, graph);
208 The \ref lemon::GraphReader::readNodeMap() "readNodeMap()"
209 function reads a map from the \c nodeset section.
210 If there is a map that you do not want to read from the file and there are
211 whitespaces in the string represenation of the values then you should
212 call the \ref lemon::GraphReader::skipNodeMap() "skipNodeMap()"
213 template member function with proper parameters.
215 \see QuotedStringReader
218 reader.readNodeMap("x-coord", xCoordMap);
219 reader.readNodeMap("y-coord", yCoordMap);
221 reader.readNodeMap<QuotedStringReader>("label", labelMap);
222 reader.skipNodeMap<QuotedStringReader>("description");
224 reader.readNodeMap("color", colorMap);
227 With the \ref lemon::GraphReader::readEdgeMap() "readEdgeMap()"
228 member function you can give an edge map
229 reading command similar to the NodeMaps.
232 reader.readEdgeMap("weight", weightMap);
233 reader.readEdgeMap("label", labelMap);
236 With \ref lemon::GraphReader::readNode() "readNode()"
237 and \ref lemon::GraphReader::readEdge() "readEdge()"
238 functions you can read labeled Nodes and
242 reader.readNode("source", sourceNode);
243 reader.readNode("target", targetNode);
245 reader.readEdge("observed", edge);
248 With \ref lemon::GraphReader::readAttribute() "readAttribute()"
249 function you can read an attribute from the file.
253 writer.readAttribute("author", author);
255 writer.writeAttribute("version", version);
258 After you give all read commands you must call the
259 \ref lemon::GraphReader::run() "run()" member
260 function, which executes all the commands.
266 If you want to lear more, read the \ref read_write_bg "background technics".