diff l1overl2.m @ 3:ee2a86d7ec07

Added support functions

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/l1overl2.m	Wed Jun 15 11:26:03 2011 +0100
@@ -0,0 +1,33 @@
+function z = l1overl2(X)
+%L1OVERL2 ratio between the l1 and the l2 norms.
+%
+% z = l1overl2(X)
+%
+% computes the ratio between the l1 and the l2 norm of the input X. If
+% input is a matrix, the norms are calculated along the columns and a mean
+% value is returned. If the input is a cell, the norms are calculated
+% independently for each cell entry and a mean value is returned.
+%
+% ----------------------------------------------------------- %
+%  Daniele Barchiesi, [e-mail]       %
+%  Centre for Digital Music, Queen Mary University of London  %
+%  Apr. 2011                                                  %
+% ----------------------------------------------------------- %
+if iscell(X)
+    nCols = length(X);
+    z = zeros(nCols,1);
+    for i=1:nCols
+        z(i) = norm(X{:,i},1)/norm(X{:,i},2);
+    end
+else
+    nCols = size(X,2);
+    z = zeros(nCols,1);
+    for i=1:nCols
+        z(i) = norm(X(:,i),1)/norm(X(:,i),2);
+    end
+end
+
+z(isnan(z)) = [];
+z = mean(z);
+
+%EOF
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