Is there any R library available to find the influence of a node in a graph. (Please see this wiki page : Node Influence Metric). I want to use two measures : Accessibility and Expected Force to measure the influence of a gene in a gene regulatory network but I cant find any R libraries in it.

igraph (CRAN) has various metrics implemented, such as

• hub score
• closeness centrality
• betweenness centrality

I don't believe expected force is yet implemented; however, Glenn Lawyer has code for it: https://github.com/glennlawyer/ExpectedForce

I am not sure about 'Accessibility' - I have not seen that mentioned as a metric.

If not igraph, take a look at Cytoscape.

Kevin