Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nan-2.5.5 / trimmean.m

diff --git a/octave_packages/nan-2.5.5/trimmean.m b/octave_packages/nan-2.5.5/trimmean.m
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+function Q=trimmean(Y,p,DIM)
+% TRIMMEAN calculates the trimmed mean by removing the fraction of p/2 upper and 
+% p/2 lower samples. Missing values (encoded as NaN) are ignored and not taken into account. 
+% The same number from the upper and lower values are removed, and is compatible to various
+% spreadsheet programs including GNumeric [1], LibreOffice, OpenOffice and MS Excel.
+%
+%  Q = trimmean(Y,p)
+%  Q = trimmean(Y,p,DIM)
+%     returns the TRIMMEAN along dimension DIM of sample array Y.
+%  If p is a vector, the TRIMMEAN for each p is computed. 
+%
+% see also: MAD, RANGE, HISTO2, HISTO3, PERCENTILE, QUANTILE
+%
+% References:
+% [1] http://www.fifi.org/doc/gnumeric-doc/html/C/gnumeric-trimmean.html
+
+
+%      $Id: trimmean.m 8953 2011-11-03 11:00:50Z schloegl $
+%      Copyright (C) 2009,2010,2011 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 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/>.
+
+if nargin<3,
+        DIM = [];
+end;
+if isempty(DIM),
+        DIM = find(size(Y)>1,1);
+        if isempty(DIM), DIM = 1; end;
+end;
+
+if nargin<2,
+       help trimmean
+        
+else
+       sz = size(Y);
+       if DIM > length(sz),
+               sz = [sz,ones(1,DIM-length(sz))];
+       end;
+
+       D1 = prod(sz(1:DIM-1));
+       D2 = length(p);
+       D3 = prod(sz(DIM+1:length(sz)));
+       Q  = repmat(nan,[sz(1:DIM-1),D2,sz(DIM+1:length(sz))]);
+       for k = 0:D1-1,
+               for l = 0:D3-1,
+                       xi = k + l * D1*sz(DIM) + 1 ;
+                       xo = k + l * D1*D2;
+                       t  = Y(xi:D1:xi+D1*sz(DIM)-1);
+                       t  = sort(t(~isnan(t)));
+                       N  = length(t); 
+                       for m=1:D2,
+                               n  = floor(N*p(m)/2);
+                               f  = sum(t(1+n:N-n))/(N-2*n);
+                               Q(xo + m*D1) = f;
+                       end; 
+               end;
+       end;
+end;
+
+%!assert(trimmean([11.4, 17.3, 21.3, 25.9, 40.1],.2),23.2)
+