danieleb@3: function z = l1overl2(X)
danieleb@3: %L1OVERL2 ratio between the l1 and the l2 norms.
danieleb@3: %
danieleb@3: % z = l1overl2(X)
danieleb@3: %
danieleb@3: % computes the ratio between the l1 and the l2 norm of the input X. If
danieleb@3: % input is a matrix, the norms are calculated along the columns and a mean
danieleb@3: % value is returned. If the input is a cell, the norms are calculated
danieleb@3: % independently for each cell entry and a mean value is returned.
danieleb@3: %
danieleb@3: % ----------------------------------------------------------- %
danieleb@3: %  Daniele Barchiesi, daniele.barchiesi@eecs.qmul.ac.uk       %
danieleb@3: %  Centre for Digital Music, Queen Mary University of London  %
danieleb@3: %  Apr. 2011                                                  %
danieleb@3: % ----------------------------------------------------------- %
danieleb@3: if iscell(X)
danieleb@3:     nCols = length(X);
danieleb@3:     z = zeros(nCols,1);
danieleb@3:     for i=1:nCols
danieleb@3:         z(i) = norm(X{:,i},1)/norm(X{:,i},2);
danieleb@3:     end
danieleb@3: else
danieleb@3:     nCols = size(X,2);
danieleb@3:     z = zeros(nCols,1);
danieleb@3:     for i=1:nCols
danieleb@3:         z(i) = norm(X(:,i),1)/norm(X(:,i),2);
danieleb@3:     end
danieleb@3: end
danieleb@3: 
danieleb@3: z(isnan(z)) = [];
danieleb@3: z = mean(z);
danieleb@3: 
danieleb@3: %EOF