Re: [igraph] igraph - problem at summary function: number of nodes does not match

[Tamás Nepusz]

> Can anyone explain why the number of nodes is 425957 instead 317080?
It is probably because you read it into igraph using the "edgelist" format, 
which assumes that vertex IDs start from zero and are continuous. If this is 
not the case, use the "ncol" format, which will simply assign integer IDs to 
the vertices and preserve the original IDs in the file in the "name" vertex 
attribute (see my_graph.vs["name"]). Also, you will need to get rid of the 
first four lines in the file and specify explicitly that your graph is 
undirected:

In [1]: g=load("com-dblp.ungraph.txt", format="ncol", directed=False)
In [2]: summary(g)
IGRAPH UN-- 317080 1049866 -- 
+ attr: name (v)

-- 
T.