alpar@209: /* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@156: *
alpar@209: * This file is a part of LEMON, a generic C++ optimization library.
alpar@156: *
alpar@156: * Copyright (C) 2003-2008
alpar@156: * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@156: * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@156: *
alpar@156: * Permission to use, modify and distribute this software is granted
alpar@156: * provided that this copyright notice appears in all copies. For
alpar@156: * precise terms see the accompanying LICENSE file.
alpar@156: *
alpar@156: * This software is provided "AS IS" with no warranty of any kind,
alpar@156: * express or implied, and with no claim as to its suitability for any
alpar@156: * purpose.
alpar@156: *
alpar@156: */
alpar@156:
alpar@156: namespace lemon {
alpar@156: /*!
alpar@156:
alpar@156:
alpar@156:
ladanyi@236: \page lgf-format LEMON Graph Format (LGF)
alpar@156:
alpar@156: The \e LGF is a column oriented
alpar@156: file format for storing graphs and associated data like
alpar@156: node and edge maps.
alpar@156:
alpar@156: Each line with \c '#' first non-whitespace
alpar@156: character is considered as a comment line.
alpar@156:
alpar@156: Otherwise the file consists of sections starting with
alpar@156: a header line. The header lines starts with an \c '@' character followed by the
alpar@156: type of section. The standard section types are \c \@nodes, \c
alpar@156: \@arcs and \c \@edges
alpar@156: and \@attributes. Each header line may also have an optional
alpar@156: \e name, which can be use to distinguish the sections of the same
alpar@156: type.
alpar@156:
alpar@156: The standard sections are column oriented, each line consists of
alpar@156: tokens separated by whitespaces. A token can be \e plain or
alpar@156: \e quoted. A plain token is just a sequence of non-whitespace characters,
alpar@156: while a quoted token is a
alpar@156: character sequence surrounded by double quotes, and it can also
alpar@209: contain whitespaces and escape sequences.
alpar@156:
alpar@156: The \c \@nodes section describes a set of nodes and associated
kpeter@192: maps. The first is a header line, its columns are the names of the
alpar@156: maps appearing in the following lines.
alpar@156: One of the maps must be called \c
alpar@156: "label", which plays special role in the file.
alpar@156: The following
alpar@156: non-empty lines until the next section describes nodes of the
alpar@156: graph. Each line contains the values of the node maps
alpar@156: associated to the current node.
alpar@156:
alpar@156: \code
alpar@156: @nodes
kpeter@212: label coordinates size title
kpeter@212: 1 (10,20) 10 "First node"
kpeter@212: 2 (80,80) 8 "Second node"
kpeter@212: 3 (40,10) 10 "Third node"
alpar@156: \endcode
alpar@156:
alpar@156: The \c \@arcs section is very similar to the \c \@nodes section,
kpeter@192: it again starts with a header line describing the names of the maps,
alpar@156: but the \c "label" map is not obligatory here. The following lines
alpar@156: describe the arcs. The first two tokens of each line are
alpar@156: the source and the target node of the arc, respectively, then come the map
alpar@156: values. The source and target tokens must be node labels.
alpar@156:
alpar@156: \code
alpar@156: @arcs
kpeter@212: capacity
alpar@156: 1 2 16
alpar@156: 1 3 12
alpar@156: 2 3 18
alpar@156: \endcode
alpar@156:
deba@201: The \c \@edges is just a synonym of \c \@arcs. The @arcs section can
deba@201: also store the edge set of an undirected graph. In such case there is
deba@201: a conventional method for store arc maps in the file, if two columns
deba@201: has the same caption with \c '+' and \c '-' prefix, then these columns
deba@201: can be regarded as the values of an arc map.
alpar@156:
alpar@156: The \c \@attributes section contains key-value pairs, each line
deba@201: consists of two tokens, an attribute name, and then an attribute
deba@201: value. The value of the attribute could be also a label value of a
deba@201: node or an edge, or even an edge label prefixed with \c '+' or \c '-',
deba@201: which regards to the forward or backward directed arc of the
deba@201: corresponding edge.
alpar@156:
alpar@156: \code
alpar@156: @attributes
alpar@156: source 1
alpar@156: target 3
alpar@156: caption "LEMON test digraph"
alpar@156: \endcode
alpar@156:
deba@162: The \e LGF can contain extra sections, but there is no restriction on
deba@162: the format of such sections.
deba@162:
alpar@156: */
alpar@156: }
alpar@156:
alpar@156: // LocalWords: whitespace whitespaces