Re: [igraph] Negative Values in PageRank

[Tamás Nepusz]

Hi,  

> I'm running igraph extension for python. I have ran the pagerank fundtion for 
> a large graph, containing ~500,000 nodes and more than million edges.
> Some of the values I got as the page rank result are negative. How is this 
> possible?

Most likely there’s some kind of a convergence problem within ARPACK (the 
eigensolver that is used to calculate the PageRank values). If your graph 
consists of multiple components, try breaking it down into individual connected 
components using the decompose() method and then calculate the PageRank scores 
individually.

All the best,
T.