GraphML import/export bug/issue

[wvermeer]

In exporting / exporting using the GraphML file format I found an issue. While exporting from Netlogo worked fine, Gephi is able to correctly opens the outputted files, getting those files imported into R however failed.

Error in .Call("R_igraph_read_graph_graphml", file, as.numeric(index), :
At foreign-graphml.c:1350 : Graph index was too large, Invalid value<

Doing some searching I found this to be a GraphML namespace issue see (https://github.com/igraph/igraph/issues/685). Testing the fix suggested in this link, the issue seems to be an incorrect link to the namesapce. GraphML namespace is http://graphml.graphdrawing.org/xmlns (according to the post) and not http://graphml.graphdrawing.org/xmlns/graphml. This indeed fixed he issue for me.

[qiemem]

It looks like this is a problem with the underlying library we're using for graphml export, Jung. Even the latest version of Jung has this bug: https://github.com/jrtom/jung/blob/master/jung-io/src/main/java/edu/uci/ics/jung/io/GraphMLWriter.java#L71

So, not much we can do about this without either writing our own exporter or forking Jung.