X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fnan-2.5.5%2Fcoefficient_of_variation.m;fp=octave_packages%2Fnan-2.5.5%2Fcoefficient_of_variation.m;h=64a44cb7531a37fafd6f52cd70c014cae6557ffa;hp=0000000000000000000000000000000000000000;hb=c880e8788dfc484bf23ce13fa2787f2c6bca4863;hpb=1705066eceaaea976f010f669ce8e972f3734b05

diff --git a/octave_packages/nan-2.5.5/coefficient_of_variation.m b/octave_packages/nan-2.5.5/coefficient_of_variation.m
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+++ b/octave_packages/nan-2.5.5/coefficient_of_variation.m
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+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;