About igraph releases and other things
There are a lot of improvements and corrections in this version. We would like to thank all the people who sent comments, bug reports, patches, or just questions. Without their contribution igraph would be definitely much less and worse than it is now. Please keep sending your comments and ideas!
Here is a list of major changes, with links to the relevant sections of the documentation. See below for the complete list of changes.
igraph includes the BLISS graph isomorphism algorithm and implementation now. This and the improved VF2 implementation, which can now calculate subgraph isomorphism, make igraph support the bleeding edge of graph isomorphism algorithms. Many thanks to the authors of BLISS. See the details in the Python documentation.
ARPACK is a library for solving large scale sparse eigenvalue problems. In igraph it is very handy, as many centrality problems are in fact eigenvalue problems: Kleinberg’s hub and authority scores, PageRank, the leading eigenvector community detection algorithm are some examples. Many thanks to the authors of ARPACK and James Fowler, who suggested to include it in igraph.
See the details in the evcent, pagerank, hub_score, etc. functions in the Python documentation.
Plotting functionality based on the Cairo graphics library (so you need to install python-cairo if you want to use it). Currently the following objects can be plotted: graphs, adjacency matrices and dendrograms. Some crude support for plotting histograms is also implemented. Plots can be saved in PNG, SVG and PDF formats.
See the details in the documentation.
igraph can now be invoked by calling the script called
igraph
from the command line. The script launches the
Python interpreter and automatically imports igraph functions into the
main namespace.
Some classic graphs can be created by giving their name. This is very handy if one needs a test graph quickly. See Famous. (The idea is based on Combinatorica, a Mathematica extension.)
Many functions were updated to handle weighted graphs: fast greedy community detection, Page Rank, modularity calculation, the Fruchterman-Reingold layout algorithm.
Some functions were added and improved to handle non-simple graphs (i.e. graphs with loop and/or multiple edges) better: testing that a graph is simple, testing for loop edges, testing for multiple edges) and counting the multiplicity of edges.
igraph Graph objects can be serialized (pickled) in Python.
This is a nice force-based layout algorithm. See the documentation of details.
igraph can now write graphs to files in the DOT format, used by GraphViz. See documentation.
Classic social network analysis tools for classifying the dyads and triads of a network.
igraph is now able to calculate biconnected components and articulation points.
These measures can be quickly estimated by specifying an upper bound for path lengths to be considered. This is useful for larger graphs, for which the calculation takes a long time. See documentation for closeness, betweenness and edge betweenness.
Two vertex similarity measures based on the number of common neighbors are introduced, the Jaccard Jaccard and the Dice similarities.
igraph
from the command line. The script launches the Python interpreter and
automatically imports igraph functions into the main namespaceGraph
objectsGraph.layout
method for accessing layout algorithmsVertexSeq
and EdgeSeq
objects can now be restricted to subsets of the
whole network (e.g., you can select vertices/edges based on attributes,
degree, centrality and so on)igraph_canonical_permutation
, igraph_isomorphic_bliss
igraph_pagerank
,
igraph_community_leading_eigenvector_*
. New functions based on
ARPACK: igraph_eigenvector_centrality
, igraph_hub_score
,
igraph_authority_score
, igraph_arpack_rssolve
, igraph_arpack_rnsolve
Experimental C attribute interface added. I.e. it is possible to use graph/vertex/edge attributes from C code now.
igraph_count_multiple
addedigraph_is_loop
and igraph_is_multiple
“return” boolean vectorsigraph_layout_graphopt
igraph_famous
igraph_lcf
, igraph_lcf_vector
igraph_add_edge
adds a single edge to the graphigraph_is_simple
addedigraph_full_citation
to create full citation networksigraph_path_length_hist
, create a histogram of path lengthsigraph_adjlist_t
,
igraph_adjedgelist_t
)igraph_le_community_to_membership
)igraph_permute_vertices
addedigraph_read_graph_*
functions can handle all possible line
terminators now (\r, \n, \r\n, \n\r)cut
vector was used