Changeset 1540:7d028a73d7f2 in lemon-0.x for doc
- Timestamp:
- 07/05/05 16:36:10 (19 years ago)
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- default
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- public
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- svn:c9d7d8f5-90d6-0310-b91f-818b3a526b0e/lemon/trunk@2034
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doc/graph_io.dox
r1532 r1540 5 5 \page graph-io-page Graph Input-Output 6 6 7 The standard graph IO enables to store graphs and additional maps 8 in a flexible and efficient way. 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". 9 11 10 12 \section format The general file format … … 18 20 \li attributes 19 21 20 The nodeset section starts with the following line: 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). 25 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 28 following line: 21 29 22 30 <tt>\@nodeset</tt> … … 25 33 following line describes a node in the graph: it contains the values of the 26 34 maps in the right order. The map named "id" should contain unique values 27 because it is regarded as an ID-map. For example: 35 because it is regarded as an ID-map. These ids need not be numbers but they 36 must identify the nodes uniquely for later reference. For example: 28 37 29 38 \code … … 40 49 <tt>\@edgeset</tt> 41 50 42 The next line contains the whitespace separated list of names of the maps. 43 Each of the next lines describes one edge. The first two elements in the line 44 are the IDs of the source and target (or tail and head) node of the edge as they occur in the ID node 45 map. You can also have an optional ID map on the edges for later reference. 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 IDs of the source and target (or tail and head) nodes of the 54 edge as they occur in the ID node map of the nodeset section. You can also 55 have an optional ID map on the edges for later reference (which has to be 56 unique in this case). 46 57 47 58 \code … … 53 64 \endcode 54 65 55 The next section contains <em>labeled nodes</em> (i.e. nodes having a special 66 The \e nodes section contains <em>labeled (distinguished) nodes</em> 67 (i.e. nodes having a special 56 68 label on them). The section starts with 57 69 … … 59 71 60 72 Each of the next lines contains a label for a node in the graph 61 and then the ID described in the nodeset section.73 and then the ID as described in the \e nodeset section. 62 74 63 75 \code … … 67 79 \endcode 68 80 69 The last section describes the <em>labeled edges</em>81 The last section describes the <em>labeled (distinguished) edges</em> 70 82 (i.e. edges having a special label on them). It starts with \c \@edges 71 83 and then each line contains the name of the edge and the ID. 72 84 73 85 \code 74 @ nodes86 @edges 75 87 observed c 76 88 \endcode … … 81 93 82 94 The attributes section can handle some information about the graph. It 83 contains in each line an key and the mapped value to key. The key should84 be a string without whitespace, the value can be from various type.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. 85 97 86 98 \code … … 92 104 \endcode 93 105 94 \code95 @end96 \endcode97 =======98 The file ends with the99 100 106 <tt> \@end </tt> 101 107 … … 104 110 105 111 \section use Using graph input-output 106 The graph input and output is based on reading and writing commands. The user 107 adds reading and writing commands to the reader or writer class, then he 108 calls the \c run() method that executes all the given commands. 112 113 The easiest way of using graph input and output is using the versions of the 114 public \ref readGraph() and \ref writeGraph() functions; if you don't need 115 very sophisticated behaviour then you might be satisfied with 116 those. Otherwise go on reading this page. 117 118 The graph input and output is based on <em> reading and writing 119 commands</em>. The user gives reading and writing commands to the reader or 120 writer class, then he calls the \c run() method that executes all the given 121 commands. 109 122 110 123 \subsection write Writing a graph … … 112 125 The \c GraphWriter class provides the graph output. To write a graph 113 126 you should first give writing commands to the writer. You can declare 114 writ ecommand as \c NodeMap or \c EdgeMap writing and labeled Node and127 writing command as \c NodeMap or \c EdgeMap writing and labeled Node and 115 128 Edge writing. 116 129 … … 120 133 121 134 The \c writeNodeMap() function declares a \c NodeMap writing command in the 122 \c GraphWriter. You should give a name ofthe map and the map135 \c GraphWriter. You should give a name to the map and the map 123 136 object as parameters. The NodeMap writing command with name "id" should write a 124 unique map because it is regarded asID map.137 unique map because it will be regarded as an ID map. 125 138 126 139 \see IdMap, DescriptorMap … … 175 188 \subsection reading Reading a graph 176 189 177 The given file formatmay contain several maps and labeled nodes or edges.190 The file to be read may contain several maps and labeled nodes or edges. 178 191 If you read a graph you need not read all the maps and items just those 179 192 that you need. The interface of the \c GraphReader is very similar to … … 189 202 \endcode 190 203 191 The \c readNodeMap() function reads a map from the \c \@nodeset section.204 The \c readNodeMap() function reads a map from the \c nodeset section. 192 205 If there is a map that you do not want to read from the file and there are 193 206 whitespaces in the string represenation of the values then you should … … 240 253 \endcode 241 254 255 \anchor rwbackground 242 256 \section types Background of Reading and Writing 257 258 243 259 To read a map (on the nodes or edges) 244 260 the \c GraphReader should know how to read a Value from the given map. … … 247 263 When the reader should skip a value in the stream, because you do not 248 264 want to store it in a map, the reader skips a character sequence without 249 whitespace .265 whitespaces. 250 266 251 267 If you want to change the functionality of the reader, you can use … … 265 281 266 282 For example, the \c "strings" nodemap contains strings and you do not need 267 the value of the string just the length. Then you can implement own Reader283 the value of the string just the length. Then you can implement an own Reader 268 284 struct. 269 285 … … 285 301 special template parameter to the GraphReader class. By default, the 286 302 template parameter is \c DefaultReaderTraits. A reader traits class 287 should provide an inner template class Reader for each type, and a n303 should provide an inner template class Reader for each type, and a 288 304 DefaultReader for skipping a value. 289 305 290 The specialization of writing should be very similar to that of reading. 291 292 \section undir Undir graphs 293 294 In the undir graph format there is an \c undiredgeset section instead of 295 the \c edgeset section. The first line of the section describes the 296 undirected egdes' names and all next lines describes one undirected edge 297 with the the incident nodes and the values of the map. 298 299 The format handles the directed edge maps as a syntactical sugar, if there 300 is two map which names are the same with a \c '+' and a \c '-' prefix 301 then it can be read as an directed map. 306 The specialization of writing is very similar to that of reading. 307 308 \section undir Undirected graphs 309 310 In a file describing an undirected graph (undir graph, for short) you find an 311 \c undiredgeset section instead of the \c edgeset section. The first line of 312 the section describes the names of the maps on the undirected egdes and all 313 next lines describe one undirected edge with the the incident nodes and the 314 values of the map. 315 316 The format handles directed edge maps as a syntactical sugar???, if there 317 are two maps with names being the same with a \c '+' and a \c '-' prefix 318 then this will be read as a directed map. 302 319 303 320 \code … … 309 326 \endcode 310 327 311 The \c edges section changed to \c undiredges section. This section328 The \c edges section is changed to \c undiredges section. This section 312 329 describes labeled edges and undirected edges. The directed edge label 313 should start with a \c '+' and a \c '-' prefix whatdecide the direction330 should start with a \c '+' or a \c '-' prefix to decide the direction 314 331 of the edge. 315 332 … … 338 355 \section advanced Advanced features 339 356 340 The graph reader and writer classes gives an easy way to read and write 341 graphs. But sometimes we want more advanced features. This way we can 342 use the more general lemon reader and writer interface. 343 344 The lemon format is an section oriented file format. It contains one or 345 more section, each starts with a line with \c \@ first character. 357 The graph reader and writer classes give an easy way to read and write 358 graphs. But sometimes we want more advanced features. In this case we can 359 use the more general <tt>lemon reader and writer</tt> interface. 360 361 The LEMON file format is a section oriented file format. It contains one or 362 more sections, each starting with a line identifying its type 363 (the word starting with the \c \@ character). 346 364 The content of the section this way cannot contain line with \c \@ first 347 365 character. The file may contains comment lines with \c # first character. … … 352 370 353 371 There are default section readers and writers for reading and writing 354 item sets, and labeled items in the graph. These read s and writes372 item sets, and labeled items in the graph. These read and write 355 373 the format described above. Other type of data can be handled with own 356 374 section reader and writer classes which are inherited from the … … 393 411 The other advanced stuff of the generalized file format is that 394 412 multiple edgesets can be stored to the same nodeset. It can be used 395 byexample as a network traffic matrix.396 397 In example there is a network with symmetric links and there are assymetric413 for example as a network traffic matrix. 414 415 In our example there is a network with symmetric links and there are assymetric 398 416 traffic request on the network. This construction can be stored in an 399 undirected graph and in a ndirected NewEdgeSetAdaptor class. The example417 undirected graph and in a directed NewEdgeSetAdaptor class. The example 400 418 shows the input with the LemonReader class: 401 419 … … 418 436 Because the GraphReader and the UndirGraphReader can be converted 419 437 to LemonReader and it can resolve the ID's of the items, the previous 420 result can be achived with the UndirGraphReader class also.438 result can be achived with the UndirGraphReader class, too. 421 439 422 440
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