Re: [igraph] reading large, sparse graph with read.graph

[Tamas Nepusz]

Heloo David,

> I would have thought that the time it would take read.graph to load into 
> memory would be O(|V|+|E|).
That might approximately be true for simple edge lists and other similar 
formats, but it is definitely not true for Pajek files because Pajek files are 
much more complicated to parse. If you need only the edges and the weights from 
your file (i.e. there are no other attributes to keep), I'd try to load the 
Pajek file first, then save it in LGL format, which can be read back faster.

> If it helps to answer, I am contemplating going outside R, and using the 
> igraph library for Ruby (in alpha). Would graphs load significantly faster 
> outside of R?
I don't think it would really matter, all the graph IO calls go down into the C 
layer of igraph, which is the same for igraph-R and igraph-Ruby.

-- 
Tamas