About igraph releases and other things

C/igraph 0.6.5

The version number is not a mistake, we jump to 0.6.5 from 0.6, for technical reasons.

Release Notes

igraph 0.6.5 is a minor release that contains only few big changes, and fixes a number of very annoying bugs.

See at the end for the complete list of changes. First let’s see the most important new features and changes.

Pajek reader supports bipartite graphs

See more here: igraph_read_graph_pajek.

Graphical degree sequences

We added some new functions if a sequence of integers is graphial, i.e. it can be the degree sequence of a simple graph. See more in the manual.

k-regular random graphs

It is possible now to generate regular random graphs, faster than the general degree sequence based generator. See more in the reference manual.

Fitting power law distributions

This release includes the plfit library to maximum likelihood fit power laws to discrete or contiouous data. See more in the reference manual.

C library news and changes

  • Added bipartite support to the Pajek reader and writer, closes bug #1042298.
  • igraph_layout_mds() uses LAPACK instead of ARPACK.
  • igraph_degree_sequence_game has a new method: IGRAPH_DEGSEQ_SIMPLE_NO_MULTIPLE.
  • Added the igraph_is_degree_sequence() and igraph_is_graphical_degree_sequence() functions.
  • igraph_rewire() has a new method: IGRAPH_REWIRING_SIMPLE_LOOPS, that can create loops.
  • Walktrap community detection now handles isolates.
  • Added igraph_k_regular_game().
  • Added igraph_power_law_fit.

  • Fixed a bug in igraph_barabasi_game when outseq was an empty vector.
  • Fixed overflow issues in centralization calculations.
  • Fixed an invalid return value of igraph_vector_ptr_pop_back.
  • Fixed a igraph_all_minimal_st_separators() bug, some vertex sets were incorrectly reported as separators. Bug #1033045.
  • Pajek exporter now always quotes strings, thanks to Elena Tea Russo.
  • Fixed a bug with handling small edge weights in igraph_shortest_paths_dijkstra(), thanks to Martin J Reed.
  • Fixed a bug in the NCV setting for ARPACK functions. It cannot be bigger than the matrix size.
  • igraph_layout_merge_dla uses better default parameter values now.
  • Fixed a bug in igraph_layout_mds() that resulted vertices on top of each other.
  • Attribute handler table is not thread-local any more.
  • Motif finding functions return IGRAPH_NAN for isomorphism classes that are not motifs (i.e. not connected). Fixes bug #1050859.
  • Fixed a bug when calculating the largest cliques of a directed graph. Bug #1073800.
  • Fix a bug in degree_sequence_game(), in_seq can be an empty vector as well instead of NULL, for an undirected graph.
  • Fixed a bug in the maximal clique search, closes #1074402.
  • Warn for negative weights when calculating PageRank.
  • Fixed a bug in igraph_eccentricity() (and also igraph_radius()), the results were often simply wrong.
  • Fixed a bug in igraph_get_all_shortest_paths_dijkstra() when edges had zero weight.
  • Fixed some potential crashes in the DrL layout generator.
  • Fixed a bug in the Reingold-Tilford layout when the graph is directed and mode != ALL.
  • Fixed a bug in igraph_has_multiple() that resulted in false negatives for some undirected graphs.
  • Fixed a crash in weighted betweenness calculation.