function y =  metaboliteConnectivity()

    S = load('hp_stoic.txt');
    %transform to 0-1 matrix
    
    nonzeros = find(S);
    S(nonzeros) = 1;
    
    % compute the degrees of metabolites

    degrees = sum(S');

    %pool the metabolites according to their connectivity 
    edges = 1:30;
    edges(end+1) = inf;
    degreePools = histc(degrees,edges);
    
    %historgram
    subplot(2,1,1), bar(degreePools);
    
    %log-log plot

   %loglog(degreePools);
    subplot(2,1,2), loglog(degreePools);
    
    y= degreePools;
    
    
    