comparison DL/two-step DL/dico_decorr.m @ 156:a4d0977d4595 danieleb

First branch commit, danieleb

     %   amp: the amplitude coefficients, only used to decide which atom to
     %   project
     %
     %   Result:
     %   dico: a dictionary close to the input one with coherence mu.
+    
+    eps = 1e-6; % define tolerance for normalisation term alpha
     
     % compute atom weights
     if nargin > 2
         rank = sum(amp.*amp, 2);
     else

     
     % several decorrelation iterations might be needed to reach global
     % coherence mu. niter can be adjusted to needs.
     niter = 1;
     while niter < 5 && ...
-            max(max(abs(dico'*dico -eye(length(dico))))) > mu + 10^-6
+            max(max(abs(dico'*dico -eye(length(dico))))) > mu + eps
         % find pairs of high correlation atoms
         colors = dico_color(dico, mu);
         
         % iterate on all pairs
         nbColors = max(colors);

                     index = fliplr(index);
                 end
                 
                 % update the atom
                 corr = dico(:,index(1))'*dico(:,index(2));
-                alpha = sqrt((1-mu*mu)/(1-corr*corr));
+                alpha = sqrt((1-mu*mu)/(1-corr^2+eps));
                 beta = corr*alpha-mu*sign(corr);
                 dico(:,index(2)) = alpha*dico(:,index(2))...
                     -beta*dico(:,index(1));
             end
         end