igraph – The network analysis package

igraph is a collection of network analysis tools with the emphasis on efficiency, portability and ease of use. igraph is open source and free. igraph can be programmed in R, Python, Mathematica and C/C++.


igraph R package python-igraph IGraph/M igraph C library

  C/igraph 0.9.2

C/igraph 0.9.2, the second 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. We have also added support for CMake package files, making it easier to use igraph in CMake-based projects.

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.

  python-igraph 0.9.1

python-igraph 0.9.1, the first bugfix release of the 0.9 series, has arrived.

The preferred way of installing the Python interface is via pip; typing pip install python-igraph should install a pre-compiled Python wheel on most supported platforms (Windows, Linux and macOS). The pre-compiled wheels and the source code are also available from the Python Package Index page.

This release brings python-igraph up-to-date with igraph 0.9.1. See the changelogs on Github for relevant changes in 0.9.0 and 0.9.1:


  C/igraph 0.9.1

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 igrapg_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!

  C/igraph 0.9.0

Release 0.9.0 of igraph’s C core has arrived, almost exactly one year after the latest minor release, 0.8.0. This release brings several new features and improvements, and also a complete switch from the old autotools-based build system to a new one based on CMake. This results in faster build times and the opportunity to use alternative build tools instead of make; in particular, igraph now support ninja and can also make use of a locally installed ccache compiler cache for even faster builds.

We gratefully acknowledge support from CZI for the development of igraph. In addition, we would like to thank everyone who reported issues, contributed features or fixes, or edited the documentation. igraph is an open-source project run by volunteers. As always, your contributions are very welcome!

Most people use igraph through its high-level interfaces for R, Python or Mathematica. A new release of the Python interface, based on 0.9.0, is expected to be released in a few days. The R and Mathematica interfaces already include some of the improvements, and will continue to integrate more.

The sources and the changelog can be obtained from the GitHub releases page.


  C/igraph 0.8.5

C/igraph 0.8.5, the fifth bugfix release of the 0.8 series, has arrived.

The sources can be obtained from the GitHub releases page.

This release includes bug fixes only. The changelog is below.

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, thanks to @jannick0
  • 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.

  C/igraph 0.8.4

C/igraph 0.8.4, the fourth bugfix release of the 0.8 series, has arrived.

The sources can be obtained from the GitHub releases page.

This release includes bug fixes and documentation improvements. The changelog is below.

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

  python-igraph 0.8.3

python-igraph 0.8.3, the third bugfix release of the 0.8 series, has arrived.

The preferred way of installing the Python interface is via pip; typing pip install python-igraph should install a pre-compiled Python wheel on most supported platforms (Windows, Linux and macOS). The pre-compiled wheels and the source code are also available from the Python Package Index page.

This release brings python-igraph up-to-date with igraph 0.8.3, and it also contains bug fixes and performance improvements. This release will also be the last one whose version number is deliberately in sync with the version number of the C core. The changelog is below.

Added

  • Graph.community_leiden() now supports a negative number of iterations; it will keep on iterating until the algorithm reaches a stable partition.

  • Graph.Incidence() now supports weighted graphs, thanks to @PuneethaPai

  • You can now create a Graph object from a pandas dataframe with Graph.DataFrame, thanks to @iosonofabio

  • Added conversion to/from networkx and graph-tool with Graph.{to,from}_{networkx,graph_tool}, thanks to @iosonofabio

  • Graph.add_edges() and Graph.add_vertices() now supports specifying attributes for the newly added vertices and edges, thanks to @iosonofabio

  • Added Graph.dfs() and Graph.dfsiter(), thanks to @iosonofabio

  • Added Graph.bridges() to get the bridges of a graph.

  • Added Graph.clear() to remove all edges, vertices and graph attributes in a single call, thanks to @iosonofabio

Changed

  • Upgraded igraph C library to 0.8.3.

  • Graph union and intersection now supports graphs with vertex names, thanks to @iosonofabio

  • Graph.delete_vertices(None) and Graph.delete_edges(None) are now deprecated; use Graph.delete_vertices() and Graph.delete_edges() (without a positional argument) instead to delete all vertices or edges. The old syntax will be removed in 0.9.

Fixed

  • setup.py now works on Windows with MinGW, thanks to @Parakoopa

  • Graph.difference() now treats loop edges correctly

  • summary() does not fail with non-string vertex names any more, thanks to @deeenes

  • The Reingold-Tilford layout should not produce edge crossings on tree graphs any more.

  • The postprocessing step of Graph.biconnected_components() is much faster now (#281); the earlier version was responsible for a significant speed difference between the C core and the Python interface.

Other

  • Various documentation improvements, thanks to @chrisfalter, @iosonofabio, @kmankinen, @remysucre, @szhorvat

  • Graph.complementer() now allows keyword arguments (it used to support positional arguments only).

  • Dropped support for Python 3.5, added support for Python 3.9.


  C/igraph 0.8.3

C/igraph 0.8.3, the third bugfix release of the 0.8 series, has arrived.

The sources can be obtained from the GitHub releases page.

This release includes bug fixes and performance improvements. The changelog is below.

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.
  • igraph_difference() was creating superfluous self loops.
  • igraph_count_multiple() was giving incorrect results for self-loops in directed graph.
  • igraph_betweenness_estimate(): fixed incorrect results with finite cutoff.
  • igraph_eigen_matrix_symmetric(): fixed incorrect matrix multiplication.
  • Corrected several issues that could arise during an error condition.
  • igraph_realize_degree_sequence() did not correctly detect some non-graphical inputs.
  • igraph_is_graphical_degree_sequence(): fixed incorrect results in undirected case.
  • igraph_community_leiden(): fixed incorrect result when self-loops are present.
  • 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.

  Funding from CZI

We are excited to announce that the igraph project will be supported with a grant of $180,000 from the Chan Zuckerberg Initiative in the Essential Open Source Software for Science program. It was recognized that igraph fulfills a critical role for providing network analysis in a variety of scientific domains, including biomedical research. The funding will expedite ongoing development efforts, and should result in a 1.0 release of igraph’s C core with a stable, well-documented and supported API.

For years, the development of igraph was done on a voluntary basis. With funding available, we can make sure developers have more time available to dedicate to igraph. In particular, the funding will support Gábor Csárdi, Tamás Nepusz, Szabolcs Horvát, Vincent Traag and Fabio Zanini.

The core of igraph is written in C, but most people use igraph through its high-level interfaces for R, Python or Mathematica. Much of the development effort will be concentrated on the core of igraph, but the high-level interfaces will not be overlooked.

Even though we will dedicate more time to igraph, the project cannot survive without a vibrant community of users and contributors. Whether you reported issues, contributed code or improved the documentation, your contributions remain vital to the project. We hope that our new community forum will enable us to form a tighter and more supportive community, where you can ask questions, support others, or discuss recent advances in network analysis or graph theory.

The project will start from the 1st of September onwards, and will last for a year. The 1.0 version is planned to be released towards the end of the project.


  C/igraph 0.8.2

C/igraph 0.8.2, the second bugfix release of the 0.8 series, has arrived.

The sources can be obtained from the GitHub releases page.

This release includes no new features, only bug fixes and reliability improvements. The changelog is below.

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.

Others

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

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