[igraph] RuntimeWarning when reading GraphML

[Chris Wj]

I assigned graph, vertex, and edge attributes to a graph and saved it to GraphML. When I read it in again, I get this message:

/usr/lib/python2.5/site-packages/python_igraph-0.6-py2.5-linux-x86_64.egg/igraph/__init__.py:1106: RuntimeWarning: Could not add vertex ids, there is already an 'id' vertex attribute at foreign-graphml.c:370

The GraphML file gets the 'id' data element for each node:

<node id="n3">
  <data key="eigenvector_centrality">0.135955</data>
  <data key="id">n3</data>
  <data key="degree">2</data>
  <data key="betweenness_centrality">0</data>
</node>

Why is it added as a data element?

-Chris