X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fnan-2.5.5%2Fmahal.m;fp=octave_packages%2Fnan-2.5.5%2Fmahal.m;h=65870405a82250434f293ad9072eaab441734a20;hp=0000000000000000000000000000000000000000;hb=c880e8788dfc484bf23ce13fa2787f2c6bca4863;hpb=1705066eceaaea976f010f669ce8e972f3734b05

diff --git a/octave_packages/nan-2.5.5/mahal.m b/octave_packages/nan-2.5.5/mahal.m
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+function [d] = mahal(X,Y)
+% MAHAL return the Mahalanobis' D-square distance between the 
+% multivariate samples x and y, which must have the same number 
+% of components (columns), but may have a different number of observations (rows). 
+% 
+%  d = mahal(X,Y)
+%
+%   d(k) = (X(k,:)-MU)*inv(SIGMA)*(X(k,:)-MU)'
+%
+%   where MU and SIGMA are the mean and the covariance matrix of Y 
+%
+%
+% see also: TRAIN_SC, TEST_SC, COVM
+%
+% References: 
+
+%	$Id: train_sc.m 2140 2009-07-02 12:03:55Z schloegl $
+%	Copyright (C) 2009 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, write to the Free Software
+% Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+
+sx = size(X);
+sy = size(Y);
+
+if sx(2)~=sy(2),
+	error('number of columns of X and Y do not fit');
+end;	
+
+IR = inv(covm(Y,'E'));
+IR(1,1) = IR(1,1)-1;
+
+D = [ones(size(X,1),1),X];
+d = sum((D*IR).*D,2);
+