[igraph] issue with giant component in python-igraph

[Anirban Dasgupta]

Hi,
   I am having an issue with the giant component. Unfortunately, the
graph involved is 500M, and have not been able to reproduce this for a
smaller graph. So it is a little hard to debug. But in case I am
making some obvious error, here is the description of the problem.

I have a (directed) graph in for following format: the vertex numbers
do start from 0 and go upto 2 million.
0  1
0  3
1  4
...
The whole graph can be stored in memory. I use the following few lines
for giant component extraction :


G = igraph.load(sys.argv[1], format="edgelist", directed=True)
components = G.clusters(igraph.WEAK)
igraph.save(components.subgraph(0), "giantcomponent.txt", format="edgelist")

I have hardcoded 0 in here (in reality I was checking the sizes of the
components.) The problem is that the giant component dumped has both
spurious edges and missing edges. Is there anything wrong in the above
command set ?  I will try to reproduce the problem for a smaller
dataset so that I can send it over.

thanks
-anirban