Reputation: 23
I need to calculate the total number of edges given the adjacency matrix for a undirected simple graph. I was told that I could perform this in MATLAB using the following:
n_edges=sum(sum(Adj))/2;
Can someone explain how it is calculating the edges?
Upvotes: 2
Views: 9043
Reputation: 5821
Just repeating my comment...
Adj(i,j) = 1
tells you there is an edge connecting nodes i
and j
. If A(i,j) = 1
then A(j,i) = 1
as well, as these indicate the same edge. Since we count every edge twice, we need to divide the total by 2.
Upvotes: 6