doc/lgf.dox
author Alpar Juttner <alpar@cs.elte.hu>
Wed, 17 Oct 2018 22:55:02 +0200
changeset 1414 73e29215aaa4
parent 1250 97d978243703
permissions -rw-r--r--
Add citation for Vf2pp (#597)
alpar@209
     1
/* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@156
     2
 *
alpar@209
     3
 * This file is a part of LEMON, a generic C++ optimization library.
alpar@156
     4
 *
alpar@1270
     5
 * Copyright (C) 2003-2013
alpar@156
     6
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@156
     7
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@156
     8
 *
alpar@156
     9
 * Permission to use, modify and distribute this software is granted
alpar@156
    10
 * provided that this copyright notice appears in all copies. For
alpar@156
    11
 * precise terms see the accompanying LICENSE file.
alpar@156
    12
 *
alpar@156
    13
 * This software is provided "AS IS" with no warranty of any kind,
alpar@156
    14
 * express or implied, and with no claim as to its suitability for any
alpar@156
    15
 * purpose.
alpar@156
    16
 *
alpar@156
    17
 */
alpar@156
    18
alpar@156
    19
namespace lemon {
alpar@156
    20
/*!
alpar@156
    21
alpar@156
    22
alpar@156
    23
ladanyi@236
    24
\page lgf-format LEMON Graph Format (LGF)
alpar@156
    25
alpar@156
    26
The \e LGF is a <em>column oriented</em>
alpar@156
    27
file format for storing graphs and associated data like
alpar@156
    28
node and edge maps.
alpar@156
    29
alpar@156
    30
Each line with \c '#' first non-whitespace
alpar@156
    31
character is considered as a comment line.
alpar@156
    32
alpar@156
    33
Otherwise the file consists of sections starting with
alpar@156
    34
a header line. The header lines starts with an \c '@' character followed by the
alpar@156
    35
type of section. The standard section types are \c \@nodes, \c
alpar@156
    36
\@arcs and \c \@edges
alpar@156
    37
and \@attributes. Each header line may also have an optional
alpar@156
    38
\e name, which can be use to distinguish the sections of the same
alpar@156
    39
type.
alpar@156
    40
alpar@156
    41
The standard sections are column oriented, each line consists of
alpar@156
    42
<em>token</em>s separated by whitespaces. A token can be \e plain or
alpar@156
    43
\e quoted. A plain token is just a sequence of non-whitespace characters,
alpar@156
    44
while a quoted token is a
alpar@156
    45
character sequence surrounded by double quotes, and it can also
alpar@209
    46
contain whitespaces and escape sequences.
alpar@156
    47
alpar@156
    48
The \c \@nodes section describes a set of nodes and associated
kpeter@192
    49
maps. The first is a header line, its columns are the names of the
alpar@156
    50
maps appearing in the following lines.
alpar@156
    51
One of the maps must be called \c
alpar@156
    52
"label", which plays special role in the file.
alpar@156
    53
The following
alpar@156
    54
non-empty lines until the next section describes nodes of the
alpar@156
    55
graph. Each line contains the values of the node maps
alpar@156
    56
associated to the current node.
alpar@156
    57
alpar@156
    58
\code
alpar@156
    59
 @nodes
kpeter@212
    60
 label  coordinates  size    title
kpeter@212
    61
 1      (10,20)      10      "First node"
kpeter@212
    62
 2      (80,80)      8       "Second node"
kpeter@212
    63
 3      (40,10)      10      "Third node"
alpar@156
    64
\endcode
alpar@156
    65
deba@1192
    66
The \e LGF files can also contain bipartite graphs, in this case a
alpar@1250
    67
\c \@red_nodes and a \c \@blue_nodes sections describe the node set of the
deba@1192
    68
graph. If a map is in both of these sections, then it can be used as a
deba@1192
    69
regular node map.
deba@1192
    70
deba@1192
    71
\code
deba@1192
    72
 @red_nodes
deba@1192
    73
 label  only_red_map   name
deba@1192
    74
 1      "cherry"       "John"
deba@1192
    75
 2      "Santa Claus"  "Jack"
deba@1192
    76
 3      "blood"        "Jason"
deba@1192
    77
 @blue_nodes
deba@1192
    78
 label  name
deba@1192
    79
 4      "Elisabeth"
deba@1192
    80
 5      "Eve"
deba@1192
    81
\endcode
deba@1192
    82
deba@1192
    83
The \c \@arcs section is very similar to the \c \@nodes section,
deba@1192
    84
it again starts with a header line describing the names of the maps,
deba@1192
    85
but the \c "label" map is not obligatory here. The following lines
deba@1192
    86
describe the arcs. The first two tokens of each line are
deba@1192
    87
the source and the target node of the arc, respectively, then come the map
alpar@156
    88
values. The source and target tokens must be node labels.
alpar@156
    89
alpar@156
    90
\code
alpar@156
    91
 @arcs
kpeter@212
    92
         capacity
alpar@156
    93
 1   2   16
alpar@156
    94
 1   3   12
alpar@156
    95
 2   3   18
alpar@156
    96
\endcode
alpar@156
    97
alpar@1067
    98
If there is no map in the \c \@arcs section at all, then it must be
alpar@1067
    99
indicated by a sole '-' sign in the first line.
alpar@1067
   100
alpar@1067
   101
\code
alpar@1067
   102
 @arcs
alpar@1067
   103
         -
alpar@1067
   104
 1   2
alpar@1067
   105
 1   3
alpar@1067
   106
 2   3
alpar@1067
   107
\endcode
alpar@1067
   108
kpeter@313
   109
The \c \@edges is just a synonym of \c \@arcs. The \@arcs section can
deba@201
   110
also store the edge set of an undirected graph. In such case there is
deba@201
   111
a conventional method for store arc maps in the file, if two columns
alpar@1067
   112
have the same caption with \c '+' and \c '-' prefix, then these columns
deba@201
   113
can be regarded as the values of an arc map.
alpar@156
   114
alpar@156
   115
The \c \@attributes section contains key-value pairs, each line
deba@201
   116
consists of two tokens, an attribute name, and then an attribute
deba@201
   117
value. The value of the attribute could be also a label value of a
deba@201
   118
node or an edge, or even an edge label prefixed with \c '+' or \c '-',
deba@201
   119
which regards to the forward or backward directed arc of the
deba@201
   120
corresponding edge.
alpar@156
   121
alpar@156
   122
\code
alpar@156
   123
 @attributes
alpar@156
   124
 source 1
alpar@156
   125
 target 3
alpar@156
   126
 caption "LEMON test digraph"
alpar@156
   127
\endcode
alpar@156
   128
deba@162
   129
The \e LGF can contain extra sections, but there is no restriction on
deba@162
   130
the format of such sections.
deba@162
   131
alpar@156
   132
*/
alpar@156
   133
}
alpar@156
   134
alpar@156
   135
//  LocalWords:  whitespace whitespaces