ivan@152: function colors = dico_color(dico, mu)
ivan@152:     % DICO_COLOR cluster a dictionary in pairs of high correlation atoms.
ivan@152:     % Called by dico_decorr.
ivan@152:     %
ivan@152:     % Parameters:
ivan@152:     % -dico: the dictionary
ivan@152:     % -mu: the correlation threshold
ivan@152:     %
ivan@152:     % Result:
ivan@152:     % -colors: a vector of indices. Two atoms with the same color have a 
ivan@152:     % correlation greater than mu 
ivan@152:     
ivan@152:     numAtoms = length(dico);
ivan@152:     colors = zeros(numAtoms, 1);
ivan@152:     
ivan@152:     % compute the correlations
ivan@152:     G = abs(dico'*dico);
ivan@152:     G = G-eye(size(G));
ivan@152:     
ivan@152:     % iterate on the correlations higher than mu
ivan@152:     c = 1;   
ivan@152:     maxCorr = max(max(G));
ivan@152:     while maxCorr > mu
ivan@152:         % find the highest correlated pair
ivan@152:         x = find(max(G)==maxCorr, 1);
ivan@152:         y = find(G(x,:)==maxCorr, 1);
ivan@152:         
ivan@152:         % color them
ivan@152:         colors(x) = c;
ivan@152:         colors(y) = c;
ivan@152:         c = c+1;
ivan@152:         
ivan@152:         % make sure these atoms never get selected again
ivan@152:         G(x,:) = 0;
ivan@152:         G(:,x) = 0;
ivan@152:         G(y,:) = 0;
ivan@152:         G(:,y) = 0;
ivan@152:         
ivan@152:         % find the next correlation
ivan@152:         maxCorr = max(max(G));
ivan@152:     end
ivan@152:     
ivan@152:     % complete the coloring with singletons
ivan@152:     index = find(colors==0);
ivan@152:     colors(index) = c:c+length(index)-1;
ivan@152: end