How to ensure that edges of an igraph object exported to graphml have edge ids?

Usage
1

I’m trying to import R igraph networks into another format so I can load them into another software package (ORA) that will let me consider dynamic networks. I have had some difficulties.
I compared some example .graphml files provided with ORA with the .graphml created from igraph with write_graph(), and noted that in the ORA files an edge will have an id:

    </edge> 
    <edge id="e1" source="n0" target="n1">
    <data key="d1">1.0</data>
    </edge>

However, the .graphml from igraph omits content such as the id="e1" above.

I don’t know if this is the source of my importing problems, but it might be a non-standard feature. Does anyone have suggestions of how to modify a graph to fix this? My experimentation so far (e.g setting E(g)$id <- E(g)) has just added to the content between <data> and </data>, so I may not be using the correct attribute name.

2

It is not possible to add the id attribute to <edge> with igraph. This is the GraphML writer code. As you can see, it is hard-coded.

However, this attribute is not required by the specification: GraphML Schema Documentation I do not see how it could cause any problems.

3

If you believe that something is wrong with the GraphML files igraph writes, it would help if you mentioned what those difficulties were (error upon importing? error messages?)

4

No actual errors in trying to import a number of igraph-generated .graphml files. But when I try to combine these in ORA, it does not produce the dynamic network that should result. My attempt to diagnose the problem prompted my question, but perhaps the issue is not due to missing edge ids. I will experiment further with ORA and add to this issue if necessary.

5

I cannot try ORA because I do not have Windows.

What kind of dynamic networks does it work with? Is it necessary for it to identify edges across different graphs?

6

As a new ORA user (on a Mac, under Parallels virtual WIndows environment) I can’t answer your questions in detail at present. However, ORA claims that you can import individual networks from various formats (e.g Pajek, graphML, are the obvious choices for igraph given what write_graph can do and that I want to preserve attributes). You can combine these networks (each representing a network at a particular time) into a dynamic network. I have succeeded in importing/combining networks, but not in visualising their dynamic behaviour. (This is what caused the troubleshooting that led to the original question here.) I am hoping to get permission to join the ORA forum and ask questions. I will report back.