[R] the largest independent (stable) set on graphs

[Diogo Alagador]

I am using the igraph package and I would like to obtain only 1  
largest independent set from a sparse graph with aprox. 600 vertices.  
When I used the largest.independent.vertex.sets command I cannot  
obtain all the sets in a decent time, even if I need only 1. Any ideas  
on how to solve this?

Thanks in advance,
Diogo Alagador
Biodiversity Chair, Univ Évora, Portugal