+function cv=coefficient_of_variation(i,DIM)
+% COEFFICIENT_OF_VARIATION returns STD(X)/MEAN(X)
+%
+% cv=coefficient_of_variation(x [,DIM])
+% cv=std(x)/mean(x)
+%
+% see also: SUMSKIPNAN, MEAN, STD
+%
+% REFERENCE(S):
+% http://mathworld.wolfram.com/VariationCoefficient.html
+
+% $Id: coefficient_of_variation.m 8223 2011-04-20 09:16:06Z schloegl $
+% Copyright (C) 1997-2003 by Alois Schloegl <alois.schloegl@gmail.com>
+% This function is part of the NaN-toolbox
+% http://pub.ist.ac.at/~schloegl/matlab/NaN/
+
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU General Public License as published by
+% the Free Software Foundation; either version 2 of the License, or
+% (at your option) any later version.
+%
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+
+if nargin<2,
+ DIM = find(size(i)>1,1);
+ if isempty(DIM), DIM=1; end;
+end;
+
+[S,N,SSQ] = sumskipnan(i,DIM);
+
+% sqrt((SSQ-S.*S./N)./max(N-1,0))/(S./N); % = std(i)/mean(i)
+
+cv = sqrt(SSQ.*N./(S.*S)-1);
+
+%if flag_implicit_unbiased_estim,
+ cv = cv.*sqrt(N./max(N-1,0));
+%end;