Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/nan-2.5.5/nanstd.m b/octave_packages/nan-2.5.5/nanstd.m
new file mode 100644 (file)
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+++ b/octave_packages/nan-2.5.5/nanstd.m
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+function [y] = nanstd(x,FLAG,DIM)
+% NANSTD same as STD but ignores NaN's. 
+% NANSTD is OBSOLETE; use NaN/STD instead. NANSTD is included 
+%    to fix a bug in alternative implementations and to 
+%    provide some compatibility. 
+%
+% Y = nanstd(x, FLAG, [,DIM])
+% 
+% x     data
+% FLAG  0: [default] normalizes with (N-1), N = sample size
+% FLAG  1: normalizes with N, N = sample size
+% DIM  dimension
+%      1 sum of columns
+%      2 sum of rows
+%      default or []: first DIMENSION with more than 1 element
+% Y    resulting standard deviation
+% 
+% see also: SUM, SUMSKIPNAN, NANSUM, STD
+
+%    $Id: nanstd.m 9033 2011-11-08 20:58:07Z schloegl $
+%    Copyright (C) 2000-2003,2006,2008,2009,2010 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<2,
+       FLAG = 0; 
+end;
+       
+if nargin<3,
+       DIM = []; 
+end;
+if isempty(FLAG), 
+        FLAG = 0; 
+end;
+if isempty(DIM), 
+        DIM = find(size(x)>1,1);
+        if isempty(DIM), DIM=1; end;
+end;
+
+[y,n,ssq] = sumskipnan(x,DIM);
+if all(ssq(:).*n(:) > 2*(y(:).^2)),
+       %% rounding error is neglectable 
+       y = ssq - y.*y./n;
+else
+       %% rounding error is not neglectable 
+       [y,n] = sumskipnan(center(x,DIM).^2,DIM);
+end; 
+
+if (FLAG==1)
+        y = sqrt(y)./n;        % normalize with N
+else
+       % default method
+        y = sqrt(y./max(n-1,0));       % normalize with N-1
+end;
+
+
+%!assert(nanstd(0),NaN)
+