easy.
%
% For more information about the adjacency matrix representation of a
% graph, see a standard book on graph algorithms.
%

%% Weighted and directed graphs
% Our previous case handled the situation for undirected graphs only.  To
% encode weighted and directed graphs, we use weighted and non-symmetric
% adjacency matrices.
%
% 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 litt