On June 17 a new version (0.6) of package ”igraph” was released. This new version abandoned the old way of indexing graph vertices with consecutive numbers starting from 0. The new version now numbers the vertices starting from 1, which is more consistent with the general R convention of indexing vectors, matrices, etc. Because this change is not backward-compatible, there is now a separate package called “igraph0″ which still uses the old 0-convention.

These changes affect the package “intergraph“.

A new version of “intergraph” (ver 1.3) is being developed to be compatible with the new “igraph” 0.6. Until it is ready, there is now package “intergraph” version 1.2 available on CRAN, which still uses the old 0-convention. It relies on legacy version of “igraph” (version 0.5, now called “igraph0″ on CRAN).

To sum up:

• If you have code that still uses the old version of “igraph” (earlier than 0.6) you should load package “igraph0″ instead of “igraph”, and use package “intergraph” version 1.2.
• If you already started using the new version of “igraph” (0.6 or later), unfortunately you have to wait until a new version of “intergraph” (1.3) is released.

Edit

As I wrote in the next post, in the end there is no package “intergraph0″, just the new version 1.2. Consequently, I have edited the description above.