igraph 1.5.1

Breaking changes

Bug fixes




igraph 1.5.0

Breaking changes

The internal format of graph objects has changed in a mostly backward-compatible way, to prepare for upgrading the C core to 0.10. Details are described at https://github.com/igraph/rigraph/wiki/The-igraph-object-format. Accessing graph objects that have been created with an older igraph version give a clean error message with instructions (#832). The new format cannot be read by igraph 1.4.3 or older, the following error is raised when trying to do so:

This graph was created by an old(er) igraph version.
  Call upgrade_graph() on it to use with the current igraph version
  For now we convert it on the fly...
Error in is_directed(object) : 
  REAL() can only be applied to a 'numeric', not a 'NULL'

The only supported remedy is to upgrade the igraph package to version 1.5.0 or later.

graph_version() now returns an integer scalar (#832, #847), 4 as of igraph 1.5.0 (#835).


Bug fixes




igraph 1.4.3



igraph 1.4.2

Breaking changes

C core

See diff for details.


Bug fixes



igraph 1.4.1

Bug fixes



igraph 1.4.0

Breaking changes





igraph 1.3.5




igraph 1.3.4



igraph 1.3.3



igraph 1.3.2

The C core is updated to 0.9.9, fixing a range of bugs.



igraph 1.3.1


igraph 1.3.0

The C core is updated to 0.9.7, fixing a range of bugs and introducing a number of new functions.






igraph 1.2.11

Dec 27, 2021

No user visible changes.

igraph 1.2.10

Dec 14, 2021


igraph 1.2.9

Nov 22, 2021

No user visible changes.

igraph 1.2.8

Oct 26, 2021

No user visible changes.

igraph 1.2.7

Oct 15, 2021

The C core is updated to 0.8.5, fixing a range of bugs and introducing a number of new functions.





igraph 1.2.6

Oct 5, 2020

No user visible changes.

igraph 1.2.5

Mar 27, 2020

No user visible changes.

igraph 1.2.4

Feb 13, 2019

No user visible changes.

igraph 1.2.3

Jan 27, 2019

No user visible changes.

igraph 1.2.2

Jul 27, 2018

No user visible changes.

igraph 1.2.1

igraph 1.1.2

Jul 20, 2017

igraph 1.1.1

Jul 13, 2017

igraph 1.0.1

June 26, 2015

Some minor updates:

igraph 1.0.0

June 21, 2015

Release notes

This is a new major version of igraph, and then why not call it 1.0.0. This does not mean that it is ready, it’ll never be ready.

The biggest changes in the release are - the new function names. Most functions were renamed to make them more consistent and readable. (Relax, old names can still be used, no need to update any code.) - Better operations for vertex and edge sequences. Most functions return proper vertex/edge sequences instead of numeric ids. - The versatile make_() and make_graph() functions to create graphs.

Major changes

Bug fixes

Too many to list. Please try if your issue was fixed and (re-)report it if not. Thanks!

igraph 0.7.1

April 21, 2014

Release Notes

Some bug fixes, to make sure that the code included in ‘Statistical Analysis of Network Data with R’ works. See https://github.com/kolaczyk/sand

Detailed changes:

igraph 0.7.0

February 4, 2014

Release Notes

There are a bunch of new features in the library itself, and other important changes in the life of the project. Thanks everyone for sending code and reporting bugs!

igraph @ github

igraph’s development has moved from Launchpad to github. This has actually happened several month ago, but never announced officially. The place for reporting bugs is at https://github.com/igraph/igraph/issues.

New homepage

igraph’s homepage is now hosted at http://igraph.org, and it is brand new. We wanted to make it easier to use and modern.

Better nightly downloads

You can download nightly builds from igraph at http://igraph.org/nightly. Source and binary R packages (for windows and OSX), are all built.

New features and bug fixes

igraph 0.6.6

Released Oct 28, 2013

Some bugs fixed:

igraph 0.6.5-2

Released May 16, 2013

Worked two CRAN check problems, and a gfortran bug (string bound checking does not work if code is called from C and without string length arguments at the “right” place).

Otherwise identical to 0.6.5-1.

igraph 0.6.5-1

Released February 27, 2013

Fixing an annoying bug, that broke two other packages on CRAN:

igraph 0.6.5

Released February 24, 2013

This is a minor release, to fix some very annoying bugs in 0.6.4:

igraph 0.6.4

Released February 2, 2013

The version number is not a mistake, we jump to 0.6.4 from 0.6, for technical reasons. This version was actually never really released, but some R packages of this version were uploaded to CRAN, so we include this version in this NEW file.

New features and bug fixes

igraph 0.6

Released June 11, 2012

See also the release notes at http://igraph.sf.net/relnotes-0.6.html

R: Major new features

R: Other new features

R: New or updated functions

Community detection

Shortest paths


Input/output and file formats

Plotting and layouts

Graph generators


igraph 0.5.3

Released November 22, 2009

Bugs corrected in the R interface

igraph 0.5.2

Released April 10, 2009

See also the release notes at http://igraph.sf.net/relnotes-0.5.2.html

New in the R interface

Bugs corrected in the R interface

igraph 0.5.1

Released July 14, 2008

See also the release notes at http://igraph.sf.net/relnotes-0.5.1.html

New in the R interface

Bugs corrected in the R interface

igraph 0.5

Released February 14, 2008

See also the release notes at http://igraph.sf.net/relnotes-0.5.html

New in the R interface

Bugs corrected in the R interface

igraph 0.4.5

Released January 1, 2008

New: - Cohesive block finding in the R interface, thanks to Peter McMahan for contributing his code. See James Moody and Douglas R. White, 2003, in Structural Cohesion and Embeddedness: A Hierarchical Conception of Social Groups American Sociological Review 68(1):1-25 - Biconnected components and articulation points. - R interface: better printing of attributes. - R interface: graph attributes can be used via ‘$’.

Bug fixed: - Erdos-Renyi random graph generators rewritten.

igraph 0.4.4

Released October 3, 2007

This release should work seamlessly with the new R 2.6.0 version. Some other bugs were also fixed: - A bug was fixed in the Erdos-Renyi graph generator, which sometimes added an extra vertex.

igraph 0.4.3

Released August 13, 2007

The next one in the sequence of bugfix releases. Thanks to many people sending bug reports. Here are the changes: - Some memory leaks removed when using attributes from R or Python. - GraphML parser: entities and character data in multiple chunks are now handled correctly. - A bug corrected in edge betweenness community structure detection, it failed if called many times from the same program/session. - Edge betweeness community structure: handle unconnected graphs properly. - Fixed bug related to fast greedy community detection in unconnected graphs. - Use a different kind of parser (Push) for reading GraphML files. This is almost invisible for users but fixed a nondeterministic bug when reading in GraphML files. - R interface: plot now handles properly if called with a vector as the edge.width argument for directed graphs. - R interface: bug (typo) corrected for walktrap.community and weighted graphs.

igraph 0.4.2

Released June 7, 2007

This is another bugfix release, as there was a serious bug in the R package of the previous version: it could not read and write graphs to files in any format under MS Windows.

Some other bits added: - circular Reingold-Tilford layout generator for trees - corrected a bug, Pajek files are written properly under MS Windows now. - arrow.size graphical edge parameter added in the R interface.

igraph 0.4.1

Released May 23, 2007

This is a minor release, it corrects a number of bugs, mostly in the R package.

igraph 0.4

Released May 21, 2007

The major new additions in this release is a bunch of community detection algorithms and support for the GML file format. Here is the complete list of changes:

New in the R interface


Bugs corrected

igraph 0.3.2

Released Dec 19, 2006

This is a new major release, it contains many new things:

Changes in the R interface

Bugs corrected

igraph 0.2.1

Released Aug 23, 2006

This is a bug-fix release. Bugs fixed: - reciprocity corrected to avoid segfaults - some docs updates - various R package updates to make it conform to the CRAN rules

igraph 0.2

Released Aug 18, 2006

Release time at last! There are many new things in igraph 0.2, the most important ones: - reading writing Pajek and GraphML formats with attributes (not all Pajek and GraphML files are supported, see documentation for details) - the RANDEDU fast motif search algorithm is implemented - many new graph generators, both games and regular graphs - many new structural properties: transitivity, reciprocity, etc. - graph operators: union, intersection, difference, structural holes, etc. - conversion between directed and undirected graphs - new layout algorithms for trees and large graphs, 3D layouts and many more.

New things specifically in the R package: - support for CTRL+C - new functions: Graph Laplacian, Burt’s constraint, etc. - vertex/edge sequences totally rewritten, smart indexing (see manual) - new R manual and tutorial: `Network Analysis with igraph’, still under development but useful - very basic 3D plotting using OpenGL

Although this release was somewhat tested on Linux, MS Windows, Mac OSX, Solaris 8 and FreeBSD, no heavy testing was done, so it might contain bugs, and we kindly ask you to send bug reports to make igraph better.

igraph 0.1

Released Jan 30, 2006

After about a year of development this is the first “official” release of the igraph library. This release should be considered as beta software, but it should be useful in general. Please send your questions and comments.