[igraph] Calculate the edge attributes based on the vertices attributes

[Seen]

Hello, I have a directed graph(G),
I have E(G)$Rates,
and V(G)$Capacity,
How can I create an edge attribute as E(from p1)$Weights = Origin
V(p1)$Rate * E(from p1)$Capacity?

Thank you very much!

-- 
Zhuojie Huang
Department of Geography
&　Emerging Pathogens Institute
University of Florida