bmailhe@200: function [colors nbColors] = dico_color_separate(dico, mu)
bmailhe@200:     % DICO_COLOR cluster several dictionaries in pairs of high correlation
bmailhe@200:     % atoms. Called by dico_decorr.
bmailhe@200:     %
bmailhe@200:     % Parameters:
bmailhe@200:     % -dico: the dictionaries
bmailhe@200:     % -mu: the correlation threshold
bmailhe@200:     %
bmailhe@200:     % Result:
bmailhe@200:     % -colors: a cell array of indices. Two atoms with the same color have
bmailhe@200:     % a correlation greater than mu
bmailhe@200:     
bmailhe@200:     
bmailhe@200:     numDico = length(dico);
bmailhe@200:     colors = cell(numDico,1);
bmailhe@200:     for i = 1:numDico
bmailhe@200:         colors{i} = zeros(length(dico{i}),1);
bmailhe@200:     end
bmailhe@200:     
bmailhe@200:     G = cell(numDico);
bmailhe@200:     
bmailhe@200:     % compute the correlations
bmailhe@200:     for i = 1:numDico
bmailhe@200:         for j = i+1:numDico
bmailhe@200:             G{i,j} = abs(dico{i}'*dico{j});
bmailhe@200:         end
bmailhe@200:     end
bmailhe@200:     
bmailhe@200:     % iterate on the correlations higher than mu
bmailhe@200:     c = 1;
bmailhe@200:     [maxCorr, i, j, m, n] = findMaxCorr(G);
bmailhe@200:     while maxCorr > mu
bmailhe@200:         % find the highest correlated pair
bmailhe@200:         
bmailhe@200:         % color them
bmailhe@200:         colors{i}(m) = c;
bmailhe@200:         colors{j}(n) = c;
bmailhe@200:         c = c+1;
bmailhe@200:         
bmailhe@200:         % make sure these atoms never get selected again
bmailhe@200:         % Set to zero relevant lines in the Gram Matrix
bmailhe@200:         for j2 = i+1:numDico
bmailhe@200:             G{i,j2}(m,:) = 0;
bmailhe@200:         end
bmailhe@200:         
bmailhe@200:         for i2 = 1:i-1
bmailhe@200:             G{i2,i}(:,m) = 0;
bmailhe@200:         end
bmailhe@200:         
bmailhe@200:         for j2 = j+1:numDico
bmailhe@200:             G{j,j2}(n,:) = 0;
bmailhe@200:         end
bmailhe@200:         
bmailhe@200:         for i2 = 1:j-1
bmailhe@200:             G{i2,j}(:,n) = 0;
bmailhe@200:         end
bmailhe@200:         
bmailhe@200:         % find the next correlation
bmailhe@200:         [maxCorr, i, j, m, n] = findMaxCorr(G);
bmailhe@200:     end
bmailhe@200:     
bmailhe@200:     % complete the coloring with singletons
bmailhe@200:     % index = find(colors==0);
bmailhe@200:     % colors(index) = c:c+length(index)-1;
bmailhe@200:     nbColors = c-1;
bmailhe@200: end
bmailhe@200: 
bmailhe@200: function [val, i, j, m, n] = findMaxCorr(G)
bmailhe@200:     %FINDMAXCORR find the maximal correlation in the cellular Gram matrix
bmailhe@200:     %
bmailhe@200:     %   Input:
bmailhe@200:     %   -G: the Gram matrix
bmailhe@200:     %
bmailhe@200:     %   Output:
bmailhe@200:     %   -val: value of the correlation
bmailhe@200:     %   -i,j,m,n: indices of the argmax. The maximal correlation is reached
bmailhe@200:     %   for the m^th atom of the i^th dictionary and the n^h atom of the
bmailhe@200:     %   j^h dictionary
bmailhe@200:     
bmailhe@200:     val = -1;
bmailhe@200:     for tmpI = 1:length(G)
bmailhe@200:         for tmpJ = tmpI+1:length(G)
bmailhe@200:             [tmpVal tmpM] = max(G{tmpI,tmpJ},[],1);
bmailhe@200:             [tmpVal tmpN] = max(tmpVal);
bmailhe@200:             if tmpVal > val
bmailhe@200:                 val = tmpVal; 
bmailhe@200:                 i = tmpI;
bmailhe@200:                 j = tmpJ;
bmailhe@200:                 n = tmpN;
bmailhe@200:                 m = tmpM(n);
bmailhe@200:             end
bmailhe@200:         end
bmailhe@200:     end
bmailhe@200: end
bmailhe@200: