C/igraph 0.10.2

C/igraph 0.10.2 is now released. The source can be obtained from the GitHub releases page , as usual.

This release brings bugfixes, some new and experimental functions, and deprecated some outdated functionality. As always, all feedback about igraph is welcome: post on this forum, or if you find problems, open a new issue in the GitHub issue tracker.


  • igraph_distances_cutoff() and igraph_distances_dijkstra_cutoff() calculate shortest paths with an upper limit on the path length (experimental functions).
  • igraph_distances_floyd_warshall() for computing all-pairs shortest path lengths in dense graphs (experimental function).
  • igraph_ecc() computes the edge clustering coefficient of some edges (experimental function).
  • igraph_voronoi() computes a Voronoi partitioning of vertices (experimental function).
  • igraph_count_multiple_1() determines the multiplicity of a single edge in the graph.
  • igraph_dqueue_get() accesses an element in a queue by index.
  • igraph_degree_1() efficiently retrieves the degee of a single vertex.
  • igraph_lazy_adjlist_has() and igraph_lazy_inclist_has() to check if adjacent vertices / incident edges have already been computed and stored for a given vertex in a lazy adjlist / inclist.


  • igraph_edge() now verifies that the input edge ID is valid.
  • igraph_community_leading_eigenvector(), igraph_adjacency_spectral_embedding(), igraph_laplacian_spectral_embedding(), igraph_arpack_rssolve() and igraph_arpack_rnsolve() now generate a random starting vector using igraph’s own RNG if needed instead of relying on LAPACK or ARPACK to do so. This makes sure that the results obtained from these functions remain the same if igraph’s RNG is seeded with the same value.
  • igraph_community_leading_eigenvector() does not stop the splitting process any more when there are multiple equally likely splits (indicated by the multiplicity of the leading eigenvector being larger than 1). The algorithm picks an arbitrary split instead and proceeds normally.


  • Fixed a bug in igraph_get_k_shortest_paths() that sometimes yielded incorrect results on undirected graphs when the mode argument was set to IGRAPH_OUT or IGRAPH_IN.
  • igraph_trussness() is now interruptible.
  • igraph_spanner() is now interruptible.
  • igraph_layout_umap() and igraph_layout_umap3d() are now interruptible.
  • In some rare cases, roundoff errors would cause igraph_distance_johnson() to fail on graphs with negative weights.
  • igraph_eulerian_cycle() and igraph_eulerian_path() now returns a more specific error code (IGRAPH_ENOSOL) when the graph contains no Eulerian cycle or path.
  • igraph_heap_init_array() did not copy the array data correctly for non-real specializations.
  • igraph_layout_umap_3d() now actually uses three dimensions.
  • igraph_layout_umap() and igraph_layout_umap_3d() are now interruptible.
  • igraph_vit_create() and igraph_eit_create() no longer fails when trying to create an iterator for the null graph or edgeless graph from an empty range-based vertex or edge selector.
  • igraph_write_graph_leda() did not correctly print attribute names in some warning messages.
  • Addressed new warnings introduced by Clang 15.
  • In the generated pkg-config file, libxml2 is now placed in the Requires.private section instead of the Libs.private one.


  • Removed unused and undocumented igraph_bfgs() function.
  • Removed the undocumented function igraph_complex_mod(). Use igraph_complex_abs() instead, as it has identical functionality.


  • The IGRAPH_EDRL error code was deprecated; the DrL algorithm now returns IGRAPH_FAILURE when it used to return IGRAPH_EDRL (not likely to happen in practice).
  • The undocumented function igraph_dqueue_e() is now deprecated and replaced by igraph_dqueue_get().
  • igraph_finite(), igraph_is_nan(), igraph_is_inf(), igraph_is_posinf() and igraph_is_neginf() are now deprecated. They were relics from a time when no standard alternatives existed. Use the C99 standard isfinite(), isnan() and isinf() instead.