Hi all,
I'm trying to calculate transitivity of the form B <- A -> C, where also B->C in a directed graph. For this I counted all the neighbors looping over each vertex using the function neighbors(graph[i], mode='out'). Then I counted the number of neighbors using the function length. Finally I get the number of possible triplets for each vertex using combinatorial, i.e. choose(number.neihgbors, 2) and I got the number of triplets of the form B <- A -> C for each vertex. When I added them all and then compare with the results from triad census for the same kind of triplets results didn't match. Any idea why? Here's the code
##Successors of A
Successor=list()
for (i in 1:vcount(el.13)){
Successor[[i]] <- neighbors(el.13, v=V(el.13)[i], mode = "out")
}
### Clustering of the form B <- A -> C, where also B->C
n.succ <- sapply(Successor, FUN=length)
trip <- choose(n.succ, 2)
triplets <- sum(trip)
Thanks!
--
Tadaishi YatabeDVM, MPVM, PhD (C)
Center for Animal Disease Modeling and Surveillance (CADMS)
Department of Medicine and Epidemiology
School of Veterinary Medicine
University of California Davis