prov in rbbt-util-5.26.8

- old
+ new

@@ -115,10 +115,10 @@
 
       R.run <<-EOF
       nodes <- read.csv("#{node_info_file}", header=T, as.is=T)
       links <- read.csv("#{edge_file}", header=T, as.is=T)
 
-      library(igraph)
+      rbbt.require('igraph')
 
       net <- graph.data.frame(links, nodes, directed=T)
       net <- simplify(net, remove.multiple = F, remove.loops = T)
 
       png("#{options[:plot]}", width=1000, height=1000)