Mercurial > octave-libtiff
view scripts/statistics/std.m @ 2311:2b5788792cad
[project @ 1996-07-11 20:18:38 by jwe]
author | jwe |
---|---|
date | Thu, 11 Jul 1996 20:18:38 +0000 |
parents | 5cffc4b8de57 |
children | 5ca126254d15 |
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### Copyright (C) 1996 John W. Eaton ### ### This file is part of Octave. ### ### Octave 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, or (at your option) ### any later version. ### ### Octave 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 Octave; see the file COPYING. If not, write to the Free ### Software Foundation, 59 Temple Place - Suite 330, Boston, MA ### 02111-1307, USA. ## usage: std (a) ## ## For vector arguments, std returns the standard deviation of the ## values. For matrix arguments, std returns a row vector containing ## the standard deviation for each column. ## ## See also: mean, median function retval = std (a) if (nargin != 1) usage ("std (a)"); endif nr = rows (a); nc = columns (a); if (nc == 1 && nr == 1) retval = 0; elseif (nc == 1 || nr == 1) n = length (a); retval = sqrt (sumsq (a - mean (a)) / (n - 1)); elseif (nr > 1 && nc > 0) retval = sqrt (sumsq (a - ones (nr, 1) * mean (a)) / (nr - 1)); else error ("std: invalid matrix argument"); endif endfunction