C/igraph 0.10.5 is now released. As usual, the source can be obtained from the GitHub releases page.
This is a maintenance release bringing bug fixes, performance improvements, as well as new experimental features. See below for details.
There are two known issues at the moment:

strtod()
does not respect the locale on macOS 13 Ventura, causing theexample::safelocale
test to fail within igraph’s test suite. This is a bug in macOS 13. This issue will be inconsequential for most users. It affects use cases when igraph is run within a process whose numeric locale has been explicitly set to one that does not use a decimal point, and thenigraph_enter_safelocale()
(or other means) are used to temporarily set the locale to"C"
before calling igraph functions. See the following links for more details: 
ARPACKNG 3.9.0 fails to produce a result under rare circumstances. This issue can affect any use of ARPACKNG in principle, and may cause igraph’s
example::centralization
andtest::centralization
tests to fail, depending on the specific configuration and BLAS implementation that is being used. For more details, see:
Added
igraph_graph_power()
computes the kth power of a graph (experimental function).igraph_community_voronoi()
for detecting communities using Voronoi partitioning (experimental function).
Changes
igraph_community_walktrap()
no longer requiresmodularity
andmerges
to be nonNULL whenmembership
is nonNULL.igraph_isomorphic()
now supports multigraphs. Shortest path related functions now consistently ignore edges with positive infinite weights.
Fixed
igraph_hub_and_authority_scores()
,igraph_hub_score()
andigraph_authority_score()
considered selfloops only once on the diagonal of the adjacency matrix of undirected graphs, thus the result was not identical to that obtained byigraph_eigenvector_centrality()
on loopy undirected graphs. This is now corrected.igraph_community_infomap()
now checks edge and vertex weights for validity.igraph_minimum_spanning_tree()
andigraph_minimum_spanning_tree_prim()
now check that edge weights are not NaN. Fixed an initialization error in the string attribute combiner of the C attribute handler.
 Fixed an issue with the weighted clique number calculation when all the weights were the same.
 HRG functions now require a graph with at least 3 vertices; previous versions crashed with smaller graphs.
igraph_arpack_rssolve()
andigraph_arpack_rnsolve()
, i.e. the ARPACK interface in igraph, are now interruptible. As a result, several other functions that rely on ARPACK (eigenvector centrality, hub and authority scores, etc.) also became interruptible.igraph_get_shortest_paths_dijkstra()
,igraph_get_all_shortest_paths_dijkstra()
andigraph_get_shortest_paths_bellman_ford()
now validate thefrom
vertex. Fixed bugs in
igraph_local_scan_1_ecount()
for weighted undirected graphs which would miscount loops and multiedges.
Deprecated
igraph_automorphisms()
is now deprecated; its new name isigraph_count_automorphisms()
. The old name is kept available until at least igraph 0.11.igraph_hub_score()
andigraph_authority_score()
are now deprecated. Useigraph_hub_and_authority_scores()
instead.igraph_get_incidence()
is now deprecated; its new name isigraph_get_biadjacency()
to reflect that the returned matrix is an adjacency matrix between pairs of vertices and not an incidence matrix between vertices and edges. The new name is kept available until at least igraph 0.11. We plan to reuse the name in later versions to provide a proper incidence matrix where the rows are vertices and the columns are edges.igraph_hrg_dendrogram()
is deprecated because it requires an attribute handler and it goes against the convention of returning attributes in vectors where possible. Useigraph_from_hrg_dendrogram()
instead, which constructs the dendrogram as an igraph graph and returns the associated probabilities in a vector.
Other
 Improved performance for
igraph_vertex_connectivity()
. igraph_simplify()
makes use of the cache, and avoids simplification when the graph is already known to be simple. Documentation improvements.