X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?a=blobdiff_plain;f=octave_packages%2Fnan-2.5.5%2Fvar.m;fp=octave_packages%2Fnan-2.5.5%2Fvar.m;h=0c33cf5efd190ac624cff391a127b53b4b4c2cfa;hb=c880e8788dfc484bf23ce13fa2787f2c6bca4863;hp=0000000000000000000000000000000000000000;hpb=1705066eceaaea976f010f669ce8e972f3734b05;p=CreaPhase.git

diff --git a/octave_packages/nan-2.5.5/var.m b/octave_packages/nan-2.5.5/var.m
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+++ b/octave_packages/nan-2.5.5/var.m
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+function y=var(x,opt,DIM,W)
+% VAR calculates the variance.
+% 
+% y = var(x [, opt[, DIM]])
+%   calculates the variance in dimension DIM
+%   the default DIM is the first non-single dimension
+%
+% opt   0: normalizes with N-1 [default]
+%	1: normalizes with N 
+% DIM	dimension
+%	1: VAR of columns
+%	2: VAR of rows
+% 	N: VAR of  N-th dimension 
+%	default or []: first DIMENSION, with more than 1 element
+% W	weights to compute weighted variance (default: [])
+%	if W=[], all weights are 1. 
+%	number of elements in W must match size(x,DIM) 
+% 
+% usage: 
+%	var(x)	
+%	var(x, opt, DIM)	
+%	var(x, [], DIM)	
+%	var(x, W, DIM)
+%	var(x, opt, DIM, W)	
+%
+% features:
+% - can deal with NaN's (missing values)
+% - weighting of data 
+% - dimension argument 
+% - compatible to Matlab and Octave
+%
+% see also: MEANSQ, SUMSQ, SUMSKIPNAN, MEAN, RMS, STD,
+
+%    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 3 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/>.
+
+%	$Id: var.m 8223 2011-04-20 09:16:06Z schloegl $
+%	Copyright (C) 2000-2003,2006,2009,2010 by Alois Schloegl <alois.schloegl@gmail.com>
+%       This is part of the NaN-toolbox for Octave and Matlab 
+%       http://pub.ist.ac.at/~schloegl/matlab/NaN/
+
+if nargin<3,
+	DIM = []; 
+end; 
+
+if nargin==1,
+	W = [];
+	opt = [];
+
+elseif any(nargin==[2,3]) 
+	if (numel(opt)<2),
+		W = [];
+	else
+		W = opt;
+		opt = []; 
+	end;
+elseif (nargin==4) && (numel(opt)<2) && (numel(DIM)<2),
+	;
+else 
+	fprintf(1,'Error VAR: incorrect usage\n');	
+	help var; 
+	return;
+end; 	
+
+if isempty(opt),
+	opt = 0;  
+end; 	
+
+if isempty(DIM), 
+        DIM = find(size(x)>1,1);
+        if isempty(DIM), DIM=1; end;
+end;
+
+[y,n,ssq] = sumskipnan(x,DIM,W);
+if all(ssq(:).*n(:) > 2*(y(:).^2)),
+	%% rounding error is neglectable 
+	y = ssq - y.*y./n;
+else
+	%% rounding error is not neglectable
+	szx = size(x);
+	szy = size(y);
+	if length(szy)<length(szx);
+        	szy(length(szy)+1:length(szx)) = 1;
+	end;
+	[y,n] = sumskipnan((x-repmat(y./n,szx./szy)).^2,DIM,W);
+end; 
+
+if (opt~=1)
+    	n = max(n-1,0);			% in case of n=0 and n=1, the (biased) variance, STD and STE are INF
+end;
+y = y./n;	% normalize
+