Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/nan-2.5.5/moment.m b/octave_packages/nan-2.5.5/moment.m
new file mode 100644 (file)
index 0000000..a00eb84
--- /dev/null
+++ b/octave_packages/nan-2.5.5/moment.m
@@ -0,0 +1,106 @@
+function M=moment(i,p,opt,DIM)
+% MOMENT estimates the p-th moment 
+% 
+% M = moment(x, p [,opt] [,DIM])
+% M = moment(H, p [,opt])
+%   calculates p-th central moment from data x in dimension DIM
+%      of from Histogram H
+%
+% p    moment of order p
+% opt   'ac': absolute 'a' and/or central ('c') moment
+%      DEFAULT: '' raw moments are estimated
+% DIM  dimension
+%      1: STATS of columns
+%      2: STATS of rows
+%      default or []: first DIMENSION, with more than 1 element
+%
+% features:
+% - can deal with NaN's (missing values)
+% - dimension argument 
+% - compatible to Matlab and Octave
+%
+% see also: STD, VAR, SKEWNESS, KURTOSIS, STATISTIC, 
+%
+% REFERENCE(S):
+% http://mathworld.wolfram.com/Moment.html
+
+%    $Id: moment.m 8223 2011-04-20 09:16:06Z schloegl $
+%    Copyright (C) 2000-2002,2010 by Alois Schloegl <alois.schloegl@gmail.com> 
+%    This functions 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==2,
+        DIM=[];
+       opt=[];        
+elseif nargin==3,
+        DIM=[];
+elseif nargin==4,
+        
+else
+        fprintf('Error MOMENT: invalid number of arguments\n');
+        return;
+end;
+
+if p<=0;
+        fprintf('Error MOMENT: invalid model order p=%f\n',p);
+        return;
+end;
+
+if isnumeric(opt) || ~isnumeric(DIM),
+        tmp = DIM;
+        DIM = opt;
+       opt = tmp;        
+end;
+if isempty(opt), 
+       opt='r';
+end;
+if isempty(DIM), 
+        DIM = find(size(i)>1,1);
+        if isempty(DIM), DIM=1; end;
+end;
+
+N = nan;        
+if isstruct(i),
+    if isfield(i,'HISTOGRAM'),
+       sz = size(i.H)./size(i.X);
+       X  = repmat(i.X,sz);
+       if any(opt=='c'),
+               N = sumskipnan(i.H,1);  % N
+               N = max(N-1,0);         % for unbiased estimation 
+               S = sumskipnan(i.H.*X,1);       % sum
+               X = X - repmat(S./N, size(X)./size(S)); % remove mean
+       end;
+       if any(opt=='a'),
+               X = abs(X);
+       end;
+       [M,n] = sumskipnan(X.^p.*i.H,1);
+    else
+       warning('invalid datatype')             
+    end;
+else
+       if any(opt=='c'),
+               [S,N] = sumskipnan(i,DIM);      % gemerate N and SUM
+               N = max(N-1,0);                 % for unbiased estimation
+               i = i - repmat(S./N, size(i)./size(S)); % remove mean
+       end;
+       if any(opt=='a'),
+               i = abs(i);     
+       end;
+       [M,n] = sumskipnan(i.^p,DIM);
+end;
+
+if isnan(N), N=n; end; 
+M = M./N;