C/igraph 0.9.1, the first bugfix release of the 0.9 series, has arrived.

The source can be obtained from the GitHub releases page.

This release includes bug fixes only, apart from a minor addition concerning lexicographic ordering of vectors, which was not substantial enough for a minor version bump. The changelog is below.

Added

• igraph_vector_lex_cmp() and igraph_vector_colex_cmp() for lexicographic and colexicographic comparison of vectors. These functions may also be used for sorting.

Changed

• igraph_community_multilevel() is now randomized (thanks to Daniel Noom).

Fixed

• CMake settings that controlled the library installation directory name, such as CMAKE_INSTALL_LIBDIR, were not respected.
• Under some conditions, the generated pkg-config file contained an incorrect include directory path.
• The following functions were not exported from the shared library: igraph_subcomponent(), igraph_stack_ptr_free_all(), igraph_stack_ptr_destroy_all(), igraph_status_handler_stderr(), igraph_progress_handler_stderr().
• Built-in random number generators (igraph_rngtype_mt19937, igraph_rngtype_rand, igraph_rngtype_glibc2) were not exported from the shared library.
• igraph_layout_graphopt() no longer rounds the spring_length parameter to an integer.
• igraph_get_all_shortest_paths_dijkstra() no longer modifies the res vector’s item destructor.
• igraph_get_shortest_path_bellman_ford() did not work correctly when calculating paths to all vertices.
• igraph_arpack_rnsolve() checks its parameters more carefully.
• igraph_community_to_membership() does not crash anymore when csize is requested but membership is not.
• igraph_citing_cited_type_game(): fixed memory leaks (thanks to Daniel Noom.
• igraph_transitivity_undirected(), igraph_transitivity_avglocal_undirected() and igraph_transitivity_barrat() no longer trigger an assertion failure when used with the null graph.
• igraph_(personalized_)pagerank() would return incorrect results for weighted multigraphs with fewer than 128 vertices when using IGRAPH_PAGERANK_ALGO_PRPACK.
• igraph_diversity() now checks its input more carefully, and throws an error when the input graph has multi-edges or is directed.
• igraph_shortest_paths_johnson() would return incorrect results when the to argument differed from from (thanks to Daniel Noom).
• igraph_is_graphical() would fail to set the result variable for certain special degree sequences in the undirected simple graph case.
• Non-maximal clique finding functions would sometimes return incomplete results when finding more than 2147483647 (i.e. 2^31 - 1) cliques.
• GLPK internal errors no longer crash igraph.
• Fixed some potential memory leaks that could happen on error conditions or when certain functions were interrupted.
• When testing a DLL build on Windows, the PATH was sometimes not set correctly, causing the tests to fail.
• When compiling from the git repository (as opposed to the release tarball), the build would fail with recent versions of bison and flex.

Other

• Documentation improvements.
• Much faster documentation builds.
• Allow using a pre-generated arith.h header for f2c when cross-compiling; see the Installation section of the documentation.
• The IGRAPH_ENABLE_LTO build option now supports the AUTO value, which uses LTO only if the compiler supports it. Warning: CMake may not always be able to detect that LTO is not fully supported. Therefore, the default setting is OFF.
• The following functions are now interruptible: igraph_grg_game(), igraph_sbm_game(), igraph_barabasi_game(), igraph_barabasi_aging_game().
• Functions that use GLPK, such as igraph_feedback_arc_set() and igraph_community_optimal_modularity() are now interruptible.
• Add support for older versions of Clang that do not recognize the -Wno-varargs flag.

Acknowledgments

• Big thanks to Daniel Noom for continuing to expand the test suite and discovering and fixing several bugs in the process!