NEWS

About igraph releases and other things

May 21, 2007

The major new additions in this release is a bunch of community detection algorithms and support for the GML file format. Here is the complete list of changes:

New in the R interface

  • as the internal representation changed, graphs stored with 'save' with an older igraph version cannot be read back with the new version reliably.
  • neighbors returns ordered lists

  • topological sorting

  • VF2 isomorphism algorithm

  • support for reading graphs from the Graph Database for isomorphism

  • girth calculation added, thanks to Keith Briggs

  • support for reading and writing GML files

  • Walktrap community detection algorithm added, thanks to Matthieu Latapy and Pascal Pons

  • edge betweenness based community detection algorithm added

  • fast greedy algorithm for community detection by Clauset et al. added thanks to Aaron Clauset for sharing his code

  • leading eigenvector community detection algorithm by Mark Newman added

  • functions for creating denrdograms from the output of the community detection algorithms added

  • community.to.membership supporting function added, creates a membership vector from a community structure merge tree

  • modularity calculation added

  • graphics parameter handling is completely rewritten, uniform handling of colors and fonts, make sure you read ?igraph.plotting

  • new plotting parameter for edges: arrow.mode

  • a bug corrected when playing a nonlinear barabasi.game

  • better looking plotting in 3d using rglplot: edges are 3d too

  • rglplot layout is allowed to be two dimensional now

  • rglplot suspends updates while drawing, this makes it faster

  • loop edges are correctly plotted by all three plotting functions

  • better printing of attributes when printing graphs

  • summary of a graph prints attribute names

  • is.igraph rewritten to make it possible to inherit from the igraph class

  • somewhat better looking progress meter for functions which support it

Others

  • many functions benefit from the new internal representation and are faster now: transitivity, reciprocity, graph operator functions like intersection and union, etc.
  • igraph compiles with Microsoft Visual C++ now
  • there were some internal changes to make igraph a real graph algorithm platform in the near future, but these are undocumented now

Bugs corrected

  • corrected a bug when reading Pajek files: directed graphs were read as undirected