[igraph] two graphs, two noncomparable sets of node IDs

[Arthur Wuster]

Hi there!

I have read a number of graphs into the igraph format. These graphs share
most of their nodes, just the edges differ. In the course reading in the
graphs, igraph converts my node names into numerical IDs, and that causes
some trouble when I want to compare graphs. For example, I would like to see
whether the degrees of nodes are correlated between my graphs. However I
can't compare nodes between graphs, because identical numerical IDs don't
refer to identical nodes in two different graphs.  

Also If I want to get for example the intersection between two graphs I
can't do this, again because of the same problem: The numerical ID which has
been assigned to each node name differs. The igraph documentation says about
this: 

" These functions do not handle vertex and edge attributes, the new graph
will have no attributes at all. Yes, this is considered to be a bug, so will
likely change in the near future."

I have studied the igraph documentation (which is otherwise excellent) the
whole afternoon and I didn't find a way around this yet. Can you help?

Best wishes, 

Arthur Wuster
Theoretical and Computational Biology
MRC Laboratory of Molecular Biology
Cambridge, UK