[Solved]: How can I compute the average weight of an undirected graph?

Problem Detail: Given a weighted, undirected graph $G = (V,E)$, how can I compute the average weight of edges?
It seems an easy problem (divide the total weight to the number of edges!) but I couldn’t manage to find the sum of the edge weights since each edge can be counted several times while iterating through the vertices.

Asked By : cagirici

Answered By : Bartosz Przybylski

If $w(i,j)$ is the weight of edge $ij$ then: $avg = frac{1}{2|E|}sum_{ineq j}w(i,j)$. Why $2E$ ? Because when traversing vertices you will calculate both edges $ij$ and $ji$. Since it’s the same edge, you are adding its weight twice, so you need to remove this redundancy by dividing by 2.
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