About igraph releases and other things

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’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.

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.

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

- Added a demo for hierarchical random graphs, invoke it via
`demo(hrg)`

. - Make attribute prefixes optional when writing a GraphML file.
- Added function
`mod.matrix()`

. - Support edge weights in leading eigenvector community detection.
- Added the LAD library for checking (sub)graph isomorphism, version 1.
- Logical attributes.
- Added
`layout.bipartite()`

function, a simple two-column layout for bipartite graphs. - Support incidence matrices in bipartite Pajek files.
- Pajek files in matrix format are now directed by default, unless they are bipartite.
- Support weighted (and signed) networks in Pajek when file is in matrix format.
- Fixed a bug in
`barabasi.game()`

, algorithm psumtree-multiple just froze. - Function
`layout.mds()`

by default returns a layout matrix now. - Added support for Boolean attributes in the GraphML and GML readers and writer.
- Change MDS layout coordinates, first dim is according to first eigenvalue, etc.
`plot.communities()`

(`plot.igraph()`

, really) draws a border around the marked groups by default.- printing graphs now converts the
`name`

graph attribute to character - Convenience functions to query and set all attributes at once:
`vertex.attriubutes()`

,`graph.attributes()`

and`edge.attributes()`

. - Function
`graph.disjoint.union()`

handles attributes now. - Rewrite
`graph.union()`

to handle attributes properly. `rewire()`

: now supports the generation and destruction of loops.- Erdos-Renyi type bipartite random graphs:
`bipartite.random.game()`

. - Support the new options (predecessors and inbound_edges) of
`get_shortest_paths()`

, reorganized the output of`get.shortest.paths()`

completely. - Added
`graphlets()`

and related functions. - Fix modularity values of multilevel community if there are no merges at all.
- Fixed bug when deleting edges with FALSE in the matrix notation.
- Fix
`bonpow()`

and`alpha.centrality()`

and make sure that the sparse solver is called. `tkplot()`

news: enable setting coordinates from the command line via`tkplot.setcoords()`

and access to the canvas via`tkplot.canvas()`

.- Fixed a potential crash in
`igraph_edge_connectivity()`

, because of an un-initialized variable in the C code. - Avoiding overflow in
`closeness()`

and related functions. - Check for NAs after converting ‘type’ to logical in
`bipartite.projection()`

. `graphNEL`

conversion functions only load the ‘graph’ package if it was not loaded before and they load it at the end of the search path, to minimize conflicts.- Fixed a bug when creating graphs from adjacency matrices, we now convert them to double, in case they are integers.
- Fixed an invalid memory read (and a potential crash) in the infomap community detection.
- Fixed a memory leak in the functions with attribute combinations.
- Removed some memory leaks from the SCG functions.
- Fixed some memory leaks in the ray tracer.
- Fixed memory leak in
`graph.bfs()`

and`graph.dfs()`

. - Fix a bug in triad census that set the first element of the result to NaN.
- Fixed a crash in
`is.chordal()`

. - Fixed a bug in weighted mudularity calculation, sum of the weights was truncated to an integer.
- Fixed a bug in weighted multilevel communtiies, the maximum weight was rounded to an integer.
- Fixed a bug in
`centralization.closeness.tmax()`

. - Reimplement push-relabel maximum flow with gap heuristics.
- Maximum flow functions now return some statistics about the push relabel algorithm steps.
- Function
`arpack()`

now gives error message if unknown options are given. - Fixed missing whitespace in Pajek writer when the ID attribute was numeric.
- Fixed a bug that caused the GML reader to crash when the ID attribute was non-numeric.
- Fixed issue #500, potential segfault if the two graphs in BLISS differ in the number of vertices or edges.
- Added
`igraphtest()`

function. - Fix dyad census instability, sometimes incorrect results were reported.
- Dyad census detects integer overflow now and gives a warning.
- Function
`add.edges()`

does not allow now zeros in the vertex set. - Added a function to count the number of adjacent triangles:
`adjacenct.triangles()`

. - Added
`graph.eigen()`

function, eigenproblems on adjacency matrices. - Added some workarounds for functions that create a lot of
graphs,
`decompose.graph()`

and`graph.neighborhood()`

use it. Fixes issue #508. - Added weights support for
`optimal.community()`

, closes #511. - Faster maximal clique finding.
- Added a function to count maximum cliques.
- Set operations: union, intersection, disjoint, union, difference, compose now work based on vertex names (if they are present) and keep attributes, closes #20.
- Removed functions
`graph.intersection.by.name()`

,`graph.union.by.name()`

,`graph.difference.by.name()`

. - The
`+`

operator on graphs now calls`graph.union()`

if both argument graphs are named, and calls`graph.disjoint.union()`

otherwise. - Added function
`igraph.version()`

. - Generate graphs from a stochastic block model:
`sbm.game()`

. - Do not suggest the stats, XML, jpeg and png packages any more.
- Fixed a
`set.vertex/edge.attribute`

bug that changed both graph objects, after copying (#533) - Fixed a bug in
`barabasi.game`

that caused crashes. - We use PRPACK to calculate PageRank scores see https://github.com/dgleich/prpack
- Added
`'which`

argument to`bipartite.projection`

(#307). - Add
`normalized`

argument to closeness functions, fixes issue #3. - R: better handling of complex attributes,
`[[`

on vertex/edge sets, fixes #231. - Implement the
`start`

argument in`hrg.fit`

(#225). - Set root vertex in Reingold-Tilford layout, solves #473.
- Fix betweenness normalization for directed graphs.
- Fixed a bug in
`graph.density`

that resulted in incorrect values for undirected graphs with loops - Fixed a bug when many graphs were created in one C call
(e.g. by
`graph.decompose`

), causing #550. - Fixed sparse
`graph.adjacency`

bugs for graphs with one edge, and graphs with zero edges. - Fixed a bug that made Bellman-Ford shortest paths calculations fail.
- Fixed a
`graph.adjacency`

bug for undirected, weighted graphs and sparse matrices. `main`

,`sub`

,`xlab`

and`ylab`

are proper graphics parameters now (#555).`graph.data.frame`

coerces arguments to data frame (#557).- Fixed a minimum cut bug for weighted undirected graphs (#564).
- Functions for simulating epidemics (SIR model) on networks,
see the
`sir`

function. - Fixed argument ordering in
`graph.mincut`

and related functions. - Avoid copying attributes in query functions and print (#573), these functions are much faster now for graphs with many vertices/edges and attributes.
- Speed up writing GML and GraphML files, if some attributes are integer. It was really-really slow.
- Fix multiple root vertices in
`graph.bfs`

(#575).