I'm currently working with large graphs (about 250,000 nodes and 1,500,000 edges). This size seems to be too large for igraph, and some operations such as diameter() take more than one day (I stopped the operation before it finished), the same thing with the average path length.
My question is does exist any way to execute igraph in parallel (using openMP for example)? I have found an R package called snowfall (http://www.imbi.uni-freiburg.de/parallel/) but I'm not sure if it is possible to run igraph with this package.