So you basically want to create an adjacency matrix from an adjacency list of edges? The number of your edges (i.e. your FID column) is irrelevant so I'm assuming your input data is of the form

edges = [1   2
         1   4
         2   3
         2   4]

Now the first column of edges is the rows of your adjacency matrix and the second is the columns (or vice versa, it doesn't matter since your matrix is symmetrical)

The simplest solution is to use linear index which you would get via the sub2ind function:

adj = inf(size(edges,2));
idx = sub2ind(size(adj),edges(:,1), edges(:,2))
adj(idx) = 1;

So you basically want to create an adjacency matrix from an adjacency list of edges? The number of your edges (i.e. your FID column) is irrelevant so I'm assuming your input data is of the form

edges = [1   2
         1   4
         2   3
         2   4]

Now the first column of edges is the rows of your adjacency matrix and the second is the columns (or vice versa, it doesn't matter since your matrix is symmetrical)

The simplest solution is to use linear index which you would get via the sub2ind function:

adj = inf(size(edges,2));
idx = sub2ind(size(adj),edges(:,1), edges(:,2))
adj(idx) = 1;

I suspect your edges matrix will already be symmetrical but if it's not then just use

edges_sym = [edges; fliplr(edges)]

instead of edges