[igraph] Local measure of reciprocity in direct graph

[capitano . nemo]

Hi,

I have a direct graph of interactions among internet users. I am looking 
for a statistic to capture the level of reciprocity/mutuality of each 
node.

In other words, in a graph g, the edges connected to a vertex v can be 
of three types: mutual, asymmetric x -> v or asymmetric v -> x. I can 
thing of two different statistics which could give you an idea of the 
"prestige" of the node:

   out.reciprocity = sum(is.mutual(g, E(g)[from(V(g)[v]), na.rm = TRUE) 
/ degree(g, E(g)[v], mode="out")

and

   in.reciprocity = sum(is.mutual(g, E(g)[to(V(g)[v]), na.rm = TRUE) / 
degree(g, E(g)[v], mode="in")

Would make sense to combine these two (in.reciprocity/out.reciprocity) 
to obtain a measure of node "prestige"?

Is there exist any other function that will do a better job?

Thanks

Francesco