fastest format to load saved graph structure into python-igraph
If you don't have vertex or edge attributes, your best bet is a simple edge list, i.e. Graph.Read_Edgelist(). The disadvantage is that it assumes that vertex IDs are in the range [0; |V|-1], so you'll need to have an additional file next to it where line i contains the name of the vertex with ID=i.
I have a very large network structure which I am working with in igraph. There are many different file formats which igraph Graph objects can write to and then be loaded from. I ran into memory problems when using g.write_picklez, and Graph.Read_Lgl() takes about 5 minutes to finish. I was wondering if anyone had already profiled the numerous file format choices for write and load speed as well as memory footprint. FYI this network has ~5.7m nodes and ~130m edges.