COIN-OR::LEMON - Graph Library

source: lemon-1.2/doc/lgf.dox @ 813:25804ef35064

Last change on this file since 813:25804ef35064 was 440:88ed40ad0d4f, checked in by Alpar Juttner <alpar@…>, 11 years ago

Happy New Year again

  • update the copyright headers + run the source unifier
File size: 3.5 KB
Line 
1/* -*- mode: C++; indent-tabs-mode: nil; -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library.
4 *
5 * Copyright (C) 2003-2009
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
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.
12 *
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
15 * purpose.
16 *
17 */
18
19namespace lemon {
20/*!
21
22
23
24\page lgf-format LEMON Graph Format (LGF)
25
26The \e LGF is a <em>column oriented</em>
27file format for storing graphs and associated data like
28node and edge maps.
29
30Each line with \c '#' first non-whitespace
31character is considered as a comment line.
32
33Otherwise the file consists of sections starting with
34a header line. The header lines starts with an \c '@' character followed by the
35type of section. The standard section types are \c \@nodes, \c
36\@arcs and \c \@edges
37and \@attributes. Each header line may also have an optional
38\e name, which can be use to distinguish the sections of the same
39type.
40
41The standard sections are column oriented, each line consists of
42<em>token</em>s separated by whitespaces. A token can be \e plain or
43\e quoted. A plain token is just a sequence of non-whitespace characters,
44while a quoted token is a
45character sequence surrounded by double quotes, and it can also
46contain whitespaces and escape sequences.
47
48The \c \@nodes section describes a set of nodes and associated
49maps. The first is a header line, its columns are the names of the
50maps appearing in the following lines.
51One of the maps must be called \c
52"label", which plays special role in the file.
53The following
54non-empty lines until the next section describes nodes of the
55graph. Each line contains the values of the node maps
56associated to the current node.
57
58\code
59 @nodes
60 label  coordinates  size    title
61 1      (10,20)      10      "First node"
62 2      (80,80)      8       "Second node"
63 3      (40,10)      10      "Third node"
64\endcode
65
66The \c \@arcs section is very similar to the \c \@nodes section,
67it again starts with a header line describing the names of the maps,
68but the \c "label" map is not obligatory here. The following lines
69describe the arcs. The first two tokens of each line are
70the source and the target node of the arc, respectively, then come the map
71values. The source and target tokens must be node labels.
72
73\code
74 @arcs
75         capacity
76 1   2   16
77 1   3   12
78 2   3   18
79\endcode
80
81The \c \@edges is just a synonym of \c \@arcs. The \@arcs section can
82also store the edge set of an undirected graph. In such case there is
83a conventional method for store arc maps in the file, if two columns
84has the same caption with \c '+' and \c '-' prefix, then these columns
85can be regarded as the values of an arc map.
86
87The \c \@attributes section contains key-value pairs, each line
88consists of two tokens, an attribute name, and then an attribute
89value. The value of the attribute could be also a label value of a
90node or an edge, or even an edge label prefixed with \c '+' or \c '-',
91which regards to the forward or backward directed arc of the
92corresponding edge.
93
94\code
95 @attributes
96 source 1
97 target 3
98 caption "LEMON test digraph"
99\endcode
100
101The \e LGF can contain extra sections, but there is no restriction on
102the format of such sections.
103
104*/
105}
106
107//  LocalWords:  whitespace whitespaces
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