thms.</p>
         <h2>Weighted and directed graphs<a name="3"></a></h2>
         <p>Our previous case handled the situation for undirected graphs only.  To encode weighted and directed graphs, we use weighted
            and non-symmetric adjacency matrices.
         </p>
         <p>For a weighted matrix, A(i,j) = distance between i and j for most of the algorithms in gaimc.  But A(i,j) = 0 means there
            is no edge, and so sometimes things can get a little tricky to get what you want.
         <