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igraph C library changelog

Unreleased

0.9.4 - 2021-05-31

Changed

  • Unweighted transitivity (i.e. clustering coefficient) calculations now ignore multi-edges and edge directions instead of rejecting multigraphs and directed graphs.
  • igraph_transitivity_barrat() now returns an error code if the input graph has multiple edges (which is not handled correctly by the implementation yet).

Fixed

  • igraph_local_scan_k_ecount() now handles loops correctly.
  • igraph_transitivity_avglocal_undirected() is no longer slower than igraph_transitivity_local_undirected().
  • Worked around an invalid warning issued by Clang 9.0 when compiling with OpenMP.

Other

  • Documentation improvements.

0.9.3 - 2021-05-05

Added

  • OpenMP is now enabled and used by certain functions (notably PageRank calculation) when the compiler supports it. Set IGRAPH_OPENMP_SUPPORT=OFF at configuration time to disable this.

Fixed

  • igraph_get_incidence() no longer reads and writes out of bounds when given a non-bipartite graph, but gives a warning and ignores edges within a part.
  • igraph_dyad_census() no longer reports an overflow on singleton graphs, and handles loops and multigraphs correctly. Undirected graphs are handled consistently and will no longer give a warning.
  • igraph_vector_lex_cmp() and igraph_vector_colex_cmp() dereferenced their arguments only once instead of twice, and therefore did not work with igraph_vector_ptr_sort().
  • igraph_maximal_cliques_subset() and igraph_transitivity_barrat() corrupted the error handling stack ("finally stack") under some circumstances.
  • CMake package files did not respect CMAKE_INSTALL_LIBDIR. This only affected Linux distributions which install into lib64 or other locations instead of lib.
  • The parser sources could not be generated when igraph was in a location that contained spaces in its path.
  • igraph no longer links to the math library (libm) when this is not necessary.
  • _CRT_SECURE_NO_WARNINGS is now defined during compilation to enable compatibility with UWP.
  • Fixed a compilation issue on MSYS / MinGW when link-time optimization was enabled and the MSYS Makefiles CMake generator was used. Some source files in igraph were renamed as a consequence, but these should not affect users of the library.

Deprecated

  • igraph_rng_min() is now deprecated; assume a constant zero as its return value if you used this function in your own code.

Other

  • Updated the vendored CXSparse library to version 3.2.0

0.9.2 - 2021-04-14

Added

  • CMake package files are now installed with igraph. This allows find_package(igraph) to find igraph and detect the appropriate compilation options for projects that link to it.

Fixed

  • igraph can now be used as a CMake subproject in other CMake-based projects.
  • The documentaton can now be built from the release tarball.
  • Configuration will no longer fail when the release tarball is extracted into a subdirectory of an unrelated git repository.
  • The generated pkg-config file was incorrect when CMAKE_INSTALL_<dir> variables were absolute paths.
  • On Unix-like systems, the library name is now libigraph.so.0.0.0, as it used to be for igraph 0.8 and earlier.
  • Fixed a return type mismatch in parser sources, and fixed some warnings with recent versions of gcc.
  • Fixed a bug in igraph_get_shortest_paths_dijkstra() and igraph_get_shortest_paths_bellman_ford() that returned incorrect results for unreachable vertices.

Other

  • Improved installation instructions and tutorial.

0.9.1 - 2021-03-23

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 (PR #1696, 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 (PR #1700, 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 (PRs #1709, #1710).
  • 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 (PR #1692).
  • 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!

0.9.0 - 2021-02-16

Added

  • Eulerian paths/cycles (PR #1346):
    • igraph_is_eulerian() finds out whether an Eulerian path/cycle exists.
    • igraph_eulerian_path() returns an Eulerian path.
    • igraph_eulerian_cycle() returns an Eulerian cycle.
  • Efficiency (PR #1344):
    • igraph_global_efficiency() computes the global efficiency of a network.
    • igraph_local_efficiency() computes the local efficiency around each vertex.
    • igraph_average_local_efficiency() computes the mean local efficiency.
  • Degree sequences (PR #1445):
    • igraph_is_graphical() checks if a degree sequence has a realization as a simple or multigraph, with or without self-loops.
    • igraph_is_bigraphical() checks if two degree sequences have a realization as a bipartite graph.
    • igraph_realize_degree_sequence() now supports constructing non-simple graphs as well.
  • There is a new fatal error handling mechanism (PR #1548):
    • igraph_set_fatal_handler() sets the fatal error handler. It is the only function in this functionality group that is relevant to end users.
    • The macro IGRAPH_FATAL() and the functions igraph_fatal() and igraph_fatalf() raise a fatal error. These are for internal use.
    • IGRAPH_ASSERT() is a replacement for the assert() macro. It is for internal use.
    • igraph_fatal_handler_abort() is the default fatal error handler.
  • The new IGRAPH_WARNINGF, IGRAPH_ERRORF and IGRAPH_FATALF macros provide warning/error reporting with printf-like syntax. (PR #1627, thanks to Daniel Noom!)
  • igraph_average_path_length_dijkstra() computes the mean shortest path length in weighted graphs (PR #1344).
  • igraph_get_shortest_paths_bellman_ford() computes the shortest paths (including the vertex and edge IDs along the paths) using the Bellman-Ford algorithm (PR #1642, thanks to Guy Rozenberg). This makes it possible to calculate the shortest paths on graphs with negative edge weights, which was not possible before with Dijkstra's algorithm.
  • igraph_get_shortest_path_bellman_ford() is a wrapper for igraph_get_shortest_paths_bellman_ford() for the single path case.
  • igraph_is_same_graph() cheks that two labelled graphs are the same (PR #1604).
  • Harmonic centrality (PR #1583):
    • igraph_harmonic_centrality() computes the harmonic centrality of vertices.
    • igraph_harmonic_centrality_cutoff() computes the range-limited harmonic centrality.
  • Range-limited centralities, currently equivalent to the old functions with names ending in _estimate (PR #1583):
    • igraph_closeness_cutoff().
    • igraph_betweenness_cutoff().
    • igraph_edge_betweenness_cutoff().
  • igraph_vector_is_any_nan() checks if any elements of an igraph_vector_t is NaN.
  • igraph_inclist_size() returns the number of vertices in an incidence list.
  • igraph_lazy_adjlist_size() returns the number of vertices in a lazy adjacency list.
  • igraph_lazy_inclist_size() returns the number of vertices in a lazy incidence list.
  • igraph_bfs_simple() now provides a simpler interface to the breadth-first search functionality.

Changed

  • igraph now uses a CMake-based build sysyem.
  • GMP support can no longer be disabled. When GMP is not present on the system, igraph will use an embedded copy of Mini-GMP (PR #1549).
  • Bliss has been updated to version 0.75. Bliss functions are now interruptible. Thanks to Tommi Junttila for making this possible!
  • Adjacency and incidence lists:
    • igraph_adjlist_init() and igraph_lazy_adjlist_init() now require the caller to specify what to do with loop and multiple edges.
    • igraph_inclist_init() and igraph_lazy_inclist_init() now require the caller to specify what to do with loop edges.
    • Adjacency and incidence lists now use igraph_vector_int_t consistently.
  • Community detection:
    • igraph_community_multilevel(): added resolution parameter.
    • igraph_community_fluid_communities(): graphs with no vertices or with one vertex only are now supported; they return a trivial partition.
  • Modularity:
    • igraph_modularity() and igraph_modularity_matrix(): added resolution parameter.
    • igraph_modularity() and igraph_modularity_matrix() now support the directed version of modularity.
    • igraph_modularity() returns NaN for graphs with no edges to indicate that the modularity is not well-defined for such graphs.
  • Centralities:
    • cutoff=0 is no longer interpreted as infinity (i.e. no cutoff) in betweenness, edge_betweenness and closeness. If no cutoff is desired, use a negative value such as cutoff=-1.
    • The nobigint argument has been removed from igraph_betweenness(), igraph_betweenness_estimate() and igraph_centralization_betweenness(), as it is not longer needed. The current implementation is more accurate than the old one using big integers.
    • igraph_closeness() now considers only reachable vertices during the calculation (i.e. the closeness is calculated per-component in the undirected case) (PR #1630).
    • igraph_closeness() gained two additional output parameters, reachable_count and all_reachable, returning the number of reached vertices from each vertex, as well as whether all vertices were reachable. This allows for computing various generalizations of closeness for disconnected graphs (PR #1630).
    • igraph_pagerank(), igraph_personalized_pagerank() and igraph_personalized_pagerank_vs() no longer support the IGRAPH_PAGERANK_ALGO_POWER method. Their options argument now has type igraph_arpack_options_t * instead of void *.
  • Shortest paths (PR #1344):
    • igraph_average_path_length() now returns the number of disconnected vertex pairs in the new unconn_pairs output argument.
    • igraph_diameter() now return the result as an igraph_real_t instead of an igraph_integer_t.
    • igraph_average_path_length() and igraph_diameter() now return IGRAPH_INFINITY when unconn=FALSE and the graph is not connected. Previously they returned the number of vertices.
  • Trait-based random graph generators:
    • igraph_callaway_traits_game() and igraph_establishment_game() now have an optional output argument to retrieve the generated vertex types.
    • igraph_callaway_traits_game() and igraph_establishment_game() now allow omitting the type distribution vector, in which case they assume a uniform distribution.
    • igraph_asymmetric_preference_game() now accept a different number of in-types and out-types.
  • igraph_subisomorphic_lad() now supports graphs with self-loops.
  • igraph_is_chordal() and igraph_maximum_cardinality_search() now support non-simple graphs and directed graphs.
  • igraph_realize_degree_sequence() has an additional argument controlling whether multi-edges or self-loops are allowed.
  • igraph_is_connected() now returns false for the null graph; see igraph#1538 for the reasoning behind this decision.
  • igraph_lapack_ddot() is renamed to igraph_blas_ddot().
  • igraph_to_directed(): added RANDOM and ACYCLIC modes (PR #1511).
  • igraph_topological_sorting() now issues an error if the input graph is not acyclic. Previously it issued a warning.
  • igraph_vector_(which_)(min|max|minmax)() now handles NaN elements.
  • igraph_i_set_attribute_table() is renamed to igraph_set_attribute_table().
  • igraph_i_sparsemat_view() is renamed to igraph_sparsemat_view().

Deprecated

  • igraph_is_degree_sequence() and igraph_is_graphical_degree_sequence() are deprecated in favour of the newly added igraph_is_graphical().
  • igraph_closeness_estimate() is deprecated in favour of the newly added igraph_closeness_cutoff().
  • igraph_betweenness_estimate() and igraph_edge_betweenness_estimate() are deprecated in favour of the newly added igraph_betweenness_cutoff() and igraph_edge_betweenness_cutoff().
  • igraph_adjlist_remove_duplicate() and igraph_inclist_remove_duplicate() are now deprecated in favour of the new constructor arguments in igraph_adjlist_init() and igraph_inclist_init().

Removed

  • The following functions, all deprecated in igraph 0.6, have been removed (PR #1562):
    • igraph_adjedgelist_init(), igraph_adjedgelist_destroy(), igraph_adjedgelist_get(), igraph_adjedgelist_print(), igraph_adjedgelist_remove_duplicate().
    • igraph_lazy_adjedgelist_init(), igraph_lazy_adjedgelist_destroy(), igraph_lazy_adjedgelist_get(), igraph_lazy_adjedgelist_get_real().
    • igraph_adjacent().
    • igraph_es_adj().
    • igraph_subgraph().
  • igraph_pagerank_old(), deprecated in 0.7, has been removed.
  • igraph_vector_bool and igraph_matrix_bool functions that relied on inequality-comparing igraph_bool_t values are removed.

Fixed

  • Betweenness calculations are no longer at risk from integer overflow.
  • The actual cutoff distance used in closeness calculation was one smaller than the cutoff parameter. This is corrected (PR #1630).
  • igraph_layout_gem() was not interruptible; now it is.
  • igraph_barabasi_aging_game() now checks its parameters more carefully.
  • igraph_callaway_traits_game() and igraph_establishment_game() now check their parameters.
  • igraph_lastcit_game() checks its parameters more carefully, and no longer crashes with zero vertices (PR #1625).
  • igraph_cited_type_game() incorrectly rounded the attractivity vector entries to integers.
  • igraph_residual_graph() now returns the correct residual capacities; previously it wrongly returned the original capacities (PR #1598).
  • igraph_psumtree_update() now checks for negative values and NaN.
  • igraph_communities_spinglass(): fixed several memory leaks in the IGRAPH_SPINCOMM_IMP_NEG implementation.
  • igraph_incident() now returns edges in the same order as igraph_neighbors().
  • igraph_modularity_matrix() returned incorrect results for weighted graphs. This is now fixed. (PR #1649, thanks to Daniel Noom!)
  • igraph_lapack_dgetrf() would crash when passing NULL for its ipiv argument (thanks for the fix to Daniel Noom).
  • Some igraph_matrix functions would fail to report errors on out-of-memory conditions.
  • igraph_maxdegree() now returns 0 for the null graph or empty vector set. Previously, it did not handle this case.
  • igraph_vector_bool_all_e() now considers all nonzero (i.e. "true") values to be the same.
  • PageRank (PR #1640):
    • igraph_(personalized_)pagerank(_vs)() now check their parameters more carefully.
    • igraph_personalized_pagerank() no longer modifies its reset parameter.
    • igraph_(personalized_)pagerank(_vs): the IGRAPH_PAGERANK_ALGO_ARPACK method now handles self-loops correctly.
    • igraph_personalized_pagerank(_vs)(): the result retuned for edgeless or all-zero-weight graphs with the IGRAPH_PAGERANK_ALGO_ARPACK ignored the personalization vector. This is now corrected.
    • igraph_personalized_pagerank(_vs)() with a non-uniform personalization vector, a disconnected graph and the IGRAPH_PAGERANK_ALGO_PRPACK method would return results that were inconsistent with IGRAPH_PAGERANK_ALGO_ARPACK. This happened because PRPACK always used a uniform reset distribution when the random walk got stuck in a sink vertex. Now it uses the user-specified reset distribution for this case as well.
  • Fixed crashes in several functions when passing a weighted graph with zero edges (due to vector_min being called on the zero-length weight vector).
  • Fixed problems in several functions when passing in a graph with zero vertices.
  • Weighted betweenness, closeness, PageRank, shortest path calculations and random walk functions now check if any weights are NaN.
  • Many functions now reject input arguments containing NaN values.
  • Compatibility with the PGI compiler.

Other

  • Documentation improvements.
  • Improved error and warning messages.
  • More robust error handling.
  • General code cleanup to reduce the number of compiler warnings.
  • igraph's source files have been re-organized for better maintainability.
  • Debugging aid: When igraph is build with AddressSanitizer, the default error handler prints a stack trace before exiting.
  • igraph can now be built with an external CXSparse library.
  • The references to igraph source files in error and warning messages are now always relative to igraph's base directory.
  • When igraph is built as a shared library, only public symbols are exported even on Linux and macOS.

Acknowledgments

  • Thanks to Daniel Noom for significantly expanding igraph's test coverage and exposing several issues in the process!

0.8.5 - 2020-12-07

Changed

  • igraph_write_graph_pajek(): the function now always uses the platform-native line endings (CRLF on Windows, LF on Unix and macOS). Earlier versions tried to enforce Windows line endings, but this was error-prone, and since all recent versions of Pajek support both line endings, enforcing Windows line endings is not necessary any more.

Fixed

  • Fixed several compilation issues with MINGW32/64 (PR #1554)
  • igraph_layout_davidson_harel() was not interruptible; now it is.
  • Added a missing memory cleanup call in igraph_i_cattribute_combine_vertices().
  • Fixed a few memory leaks in test cases.

0.8.4 - 2020-11-24

Fixed

  • igraph_i_cattribute_combine_vertices(): fixed invalid cleanup code that eventually filled up the "finally" stack when combining vertices with attributes extensively.
  • igraph_hrg_sample(): fixed incorrect function prototype
  • igraph_is_posinf() and igraph_is_neginf(): fixed incorrect result on platforms where the sign of the result of isinf() is not indicative of the sign of the input.
  • Fixed building with vendored LAPACK and external BLAS
  • Fixed building with XCode 12.2 on macOS

Other

  • Documentation improvements
  • General code cleanup to reduce the number of compiler warnings

0.8.3 - 2020-10-02

Added

  • igraph_vector_binsearch_slice() performs binary search on a sorted slice of a vector.

Changed

  • igraph_eigenvector_centrality() assumes the adjacency matrix of undirected graphs to have twice the number of self-loops for each vertex on the diagonal. This makes the results consistent between an undirected graph and its directed equivalent when each edge is replaced by a mutual edge pair.

Fixed

  • igraph_isomorphic() now verifies that the input graphs have no multi-edges (PR #1464).
  • igraph_difference() was creating superfluous self loops (#597).
  • igraph_count_multiple() was giving incorrect results for self-loops in directed graph (PR #1399).
  • igraph_betweenness_estimate(): fixed incorrect results with finite cutoff (PR #1392).
  • igraph_count_multiple() was giving incorrect results for self-loops in directed graph (PR #1399).
  • igraph_eigen_matrix_symmetric(): fixed incorrect matrix multiplication (PR #1379).
  • Corrected several issues that could arise during an error condition (PRs #1405, #1406, #1438).
  • igraph_realize_degree_sequence() did not correctly detect some non-graphical inputs.
  • igraph_is_graphical_degree_sequence(): fixed incorrect results in undirected case (PR #1441).
  • igraph_community_leiden(): fixed incorrect result when self-loops are present (PR #1476).
  • igraph_eigenvector_centrality(): fixed incorrect value for isolated vertices in weighted graphs.
  • igraph_eigenvector_centrality(): corrected the handling of self-loops.
  • igraph_layout_reingold_tilford(): fixed an issue where branches of the tree would sometimes overlap.

Other

  • igraph_degree_sequence_game(): improved performance with IGRAPH_DEGSEQ_SIMPLE_NO_MULTIPLE_UNIFORM method.
  • Improved the robustness of the test suite.
  • Documentation improvements.
  • Improved error and warning messages.
  • Improved compatibility with recent versions of Microsoft Visual C.

0.8.2 - 2020-04-28

Changed

  • Improved argument checking: igraph_all_st_mincuts() and igraph_sir()
  • Improved interruptibility: igraph_sir()

Fixed

  • igraph_community_leiden(): fixed crash when interrupting
  • The tests are now more robust. Some incorrect test failures were fixed when running on i386 architecture, or when using different versions of external dependencies.

Other

  • Improved error messages from igraph_sir().
  • Improved compatibility with more recent versions of Microsoft Visual C.

0.8.1 - 2020-03-13

Changed

  • Improved interruptability: igraph_degree_sequence_game()
  • Improved argument checking: igraph_forest_fire_game()
  • Updated the plfit library to version 0.8.1

Fixed

  • igraph_community_edge_betweenness(): fix for graphs with no edges (PR #1312)
  • igraph_bridges() now handles multigraphs correctly (PR #1335)
  • igraph_avg_nearest_neighbor_degree(): fix for memory leak in weighted case (PR #1339)
  • igraph_community_leiden(): fix crash bug (PR #1357)

Other

  • Included ACKOWLEDGEMENTS.md
  • Documentation improvements

0.8.0 - 2020-01-29

Added

  • Trees

    • igraph_to_prufer() and igraph_from_prufer() convert labelled trees to/from Prüfer sequences
    • igraph_tree_game() samples uniformly from the set of labelled trees
    • igraph_is_tree() checks if a graph is a tree
    • igraph_random_spanning_tree() picks a spanning tree of a graph uniformly at random
    • igraph_random_edge_walk() returns the indices of edges traversed by a random walk; useful for multigraphs

  • Community detection

    • igraph_community_fluid_communities() detects communities based on interacting fluids
    • igraph_community_leiden() detects communities with the Leiden method

  • Cliques

    • igraph_maximal_cliques_hist() counts maximal cliques of each size
    • igraph_maximal_cliques_callback() calls a function for each maximal clique
    • igraph_clique_size_hist() counts cliques of each size
    • igraph_cliques_callback() calls a function for each clique
    • igraph_weighted_cliques() finds weighted cliques in graphs with integer vertex weights
    • igraph_weighted_clique_number() computes the weighted clique number
    • igraph_largest_weighted_cliques() finds the largest weighted cliques

  • Graph generators

    • igraph_hsbm_game() for a hierarchical stochastic block model
    • igraph_hsbm_list_game() for a more general hierarchical stochastic block model
    • igraph_correlated_game() generates pairs of correlated random graphs by perturbing existing adjacency matrix
    • igraph_correlated_pair_game() generates pairs of correlated random graphs
    • igraph_tree_game() samples uniformly from the set of labelled trees
    • igraph_dot_product_game() generates a random dot product graph
    • igraph_realize_degree_sequence() creates a single graph with a given degree sequence (Havel-Hakimi algorithm)

  • Graph embeddings

    • igraph_adjacency_spectral_embedding() and igraph_laplacian_spectral_embedding() provide graph embedddings
    • igraph_dim_select() provides dimensionality selection for singular values using profile likelihood

  • Isomorphism

    • igraph_automorphism_group() computes the generators of the automorphism group of a simple graph
    • igraph_simplify_and_colorize() encodes edge and self-loop multiplicities into edge and vertex colors; use in conjunction with VF2 to test isomorphism of non-simple graphs

  • Other

    • igraph_bridges() finds edges whose removal would disconnect a graph
    • igraph_vertex_coloring_greedy() computes a vertex coloring using a greedy algorithm
    • igraph_rewire_directed_edges() randomly rewires only the starting points or only the endpoints of directed edges
    • Various igraph_local_scan_* functions provide local counts and statistics of neighborhoods
    • igraph_sample_sphere_surface() samples points uniformly from the surface of a sphere
    • igraph_sample_sphere_volume() samples points uniformly from the volume of a sphere
    • igraph_sample_dirichlet() samples points from a Dirichlet distribution
    • igraph_malloc(), to be paired with the existing igraph_free()

Changed

  • igraph_degree_sequence_game(): new method added for uniform sampling: IGRAPH_DEGSEQ_SIMPLE_NO_MULTIPLE_UNIFORM
  • igraph_modularity_matrix(): removed membership argument (PR #1194)
  • igraph_avg_nearest_neighbor_degree(): added mode and neighbor_degree_mode arguments (PR #1214).
  • igraph_get_all_simple_paths(): added cutoff argument (PR #1232).
  • igraph_unfold_tree(): no longer preserves edge ordering of original graph
  • igraph_decompose(): support strongly connected components
  • igraph_isomorphic_bliss(), igraph_canonical_permutation(), igraph_automorphisms(): added additional arguments to support vertex colored graphs (PR #873)
  • igraph_extended_chordal_ring: added argument to support direction (PR #1096), and fixed issue #1093.

Other

  • The Bliss isomorphism library was updated to version 0.73. This version adds support for vertex colored and directed graphs.
  • igraph now uses the high-performance Cliquer library to find (non-maximal) cliques
  • Provide proper support for Windows, using __declspec(dllexport) and __declspec(dllimport) for DLLs and static usage by using #define IGRAPH_STATIC 1.
  • Provided integer versions of dqueue and stack data types.