dDAGroot is supposed to find the root node of a direct acyclic
graph (DAG; an ontology). It return the name (i.e Term ID) of the root
root: the root name (i.e. Term ID)
# 1) load HPPA as igraph object ig.HPPA <-dRDataLoader(RData='ig.HPPA')'ig.HPPA' (from package 'dnet' version 1.1.2) has been loaded into the working environment (at 2018-01-19 12:35:02)g <- ig.HPPA # 2) find the root root <- dDAGroot(g) root "HP:0000118"