LEDA (.gw, .lgr)

Background & Context

    • LEDA graph data format.
    • Commonly used exchange format for graphs.
    • Stores a single, typed, directed, or undirected graph.
    • Plain text format.
    • Native graph file format of the LEDA graph library and the GraphWin application.
    • LEDA is an acronym for Library of Efficient Datatypes and Algorithms.
    • Developed in the 1990s at Max Planck Institute for Informatics Saarbrücken.

Import & Export

  • Import["file.gw"] gives a Graph object representing the graph stored in the specified file.
  • Export["file.gw",expr] exports an adjacency matrix or edge information representing a graph to the LEDA format.
  • Import["file.gw"] imports the graph from file and returns it as a Graph.
  • Import["file.gw",elem] imports the specified element from a LEDA file.
  • Import["file.gw",{{elem1,elem2,}}] imports multiple elements.
  • The import format can be specified with Import["file","LEDA"] or Import["file",{"LEDA",elem,}].
  • Export["file.gw",expr,elem] creates a LEDA file by treating expr as specifying element elem.
  • Export["file.gw",{expr1,expr2,},{{elem1,elem2,}}] treats each expri as specifying the corresponding elemi.
  • Export["file.gw",expr,opt1->val1,] exports expr with the specified option elements taken to have the specified values.
  • Export["file.gw",{elem1->expr1,elem2->expr2,},"Rules"] uses rules to specify the elements to be exported.
  • See the following reference pages for full general information:
  • Import, Exportimport from or export to a file
    CloudImport, CloudExportimport from or export to a cloud object
    ImportString, ExportStringimport from or export to a string
    ImportByteArray, ExportByteArrayimport from or export to a byte array

Import Elements

  • General Import elements:
  • "Elements" list of elements and options available in this file
    "Summary"summary of the file
    "Rules"list of rules for all available elements
  • Data representation elements:
  • "AdjacencyMatrix"edge information, given as a matrix
    "EdgeData"edge data, given as a list
    "EdgeRules"connectivity data for the graph, given as a list of rules
    "EdgeType"edge data type, given as a string
    "Graph"graph stored in the file, given as a Graph object
    "Graphics"graph stored in the file, rendered as a graph plot
    "VertexCount"number of vertices in the graph
    "VertexData"vertex data, given as a list
    "VertexType"vertex data type, given as a string
  • Import by default uses the "Graph" element when importing from LEDA.



Basic Examples  (8)

Import a Graph object from a LEDA file:

Show vertex labels in the Graph:

Show the Import elements available for a LEDA file:

Import connectivity rules:

Import the edge and vertex data stored in a LEDA graph file:

Export a Graph to the LEDA format:

Export an asymmetric adjacency matrix of a graph to the LEDA format:

Convert a list of edge rules representing an undirected graph to the LEDA language: