--- /dev/null
+function [y]=mean(x,DIM,opt,W)
+% MEAN calculates the mean of data elements.
+%
+% y = mean(x [,DIM] [,opt] [, W])
+%
+% DIM dimension
+% 1 MEAN of columns
+% 2 MEAN of rows
+% N MEAN of N-th dimension
+% default or []: first DIMENSION, with more than 1 element
+%
+% opt options
+% 'A' arithmetic mean
+% 'G' geometric mean
+% 'H' harmonic mean
+%
+% W weights to compute weighted mean (default: [])
+% if W=[], all weights are 1.
+% number of elements in W must match size(x,DIM)
+%
+% usage:
+% mean(x)
+% mean(x,DIM)
+% mean(x,opt)
+% mean(x,opt,DIM)
+% mean(x,DIM,opt)
+% mean(x,DIM,W)
+% mean(x,DIM,opt,W); '
+%
+% features:
+% - can deal with NaN's (missing values)
+% - weighting of data
+% - dimension argument also in Octave
+% - compatible to Matlab and Octave
+%
+% see also: SUMSKIPNAN, MEAN, GEOMEAN, HARMMEAN
+%
+
+% $Id: mean.m 9033 2011-11-08 20:58:07Z schloegl $
+% Copyright (C) 2000-2004,2008,2009,2011 by Alois Schloegl <alois.schloegl@gmail.com>
+% This is part of the NaN-toolbox. For more details see
+% 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==1,
+ %------ case: mean(x)
+ W = [];
+ DIM=[];
+ opt='a';
+elseif (nargin==2)
+ W = [];
+ %if ~isnumeric(DIM), %>=65;%abs('A'),
+ if (DIM>64) %abs('A'),
+ %------ case: mean(x,opt)
+ opt=DIM;
+ DIM=[];
+ else
+ %------ case: mean(x,DIM)
+ opt='a';
+ end;
+elseif (nargin == 3),
+ if isnumeric(DIM) && isnumeric(opt)
+ %------ case: mean(x,DIM,W)
+ W = opt;
+ opt='a';
+ elseif (DIM>64) %abs('A'),
+ %------ case: mean(x,opt,DIM)
+ %if ~isnumeric(DIM), %>=65;%abs('A'),
+ tmp=opt;
+ opt=DIM;
+ DIM=tmp;
+ W = [];
+ else
+ %------ case: mean(x,DIM,opt)
+ W = [];
+ end;
+elseif nargin==4,
+ %------ case: mean(x,DIM,opt,W)
+ ;
+else
+ help mean
+% fprintf(1,'usage: mean(x) or mean(x,DIM) or mean(x,opt,DIM) or mean(x,DIM,opt) or mean(x,DIM,W) or mean(x,DIM,opt,W); '
+end;
+
+if isempty(opt)
+ opt = 'A';
+elseif any(opt=='aAgGhH')
+ opt = upper(opt); % eliminate old version
+else
+ error('Error MEAN: invalid opt argument');
+end;
+
+if (opt == 'A')
+ [y, n] = sumskipnan(x,DIM,W);
+ y = y./n;
+elseif (opt == 'G')
+ [y, n] = sumskipnan(log(x),DIM,W);
+ y = exp (y./n);
+elseif (opt == 'H')
+ [y, n] = sumskipnan(1./x,DIM,W);
+ y = n./y;
+else
+ fprintf (2,'mean: option `%s` not recognized', opt);
+end
+
+%!assert(mean([1,NaN],1),[1,NaN])
+%!assert(mean([1,NaN],2),1)
+%!assert(mean([+inf,-inf]),NaN)
+%!assert(mean([+0,-0],'h'),NaN)
+%!assert(mean([1,4,NaN],'g'),2)
+
+
+