COIN-OR::LEMON - Graph Library

source: lemon/doc/lgf.dox @ 178:d2bac07f1742

Last change on this file since 178:d2bac07f1742 was 162:33247f6fff16, checked in by Balazs Dezso <deba@…>, 17 years ago

Section reader for DigraphReader?

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[156]1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
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, it 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 arc,
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.
82
83The \c \@attributes section contains key-value pairs, each line
84consists of two tokens, an attribute name, and then an attribute value.
85
86\code
87 @attributes
88 source 1
89 target 3
90 caption "LEMON test digraph"
91\endcode
92
[162]93The \e LGF can contain extra sections, but there is no restriction on
94the format of such sections.
95
[156]96*/
97}
98
99//  LocalWords:  whitespace whitespaces
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