Mercurial > octave-nkf
view scripts/statistics/base/iqr.m @ 5307:4c8a2e4e0717
[project @ 2005-04-26 19:24:27 by jwe]
author | jwe |
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date | Tue, 26 Apr 2005 19:24:47 +0000 |
parents | 54b076a24718 |
children | 2a16423e4aa0 |
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## Copyright (C) 1995, 1996, 1997 Kurt Hornik ## ## 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA ## 02110-1301, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} iqr (@var{x}, @var{dim}) ## If @var{x} is a vector, return the interquartile range, i.e., the ## difference between the upper and lower quartile, of the input data. ## ## If @var{x} is a matrix, do the above for first non singleton ## dimension of @var{x}.. If the option @var{dim} argument is given, ## then operate along this dimension. ## @end deftypefn ## Author KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: Interquartile range function y = iqr (x, dim) if (nargin != 1 && nargin != 2) usage ("iqr (x, dim)"); endif nd = ndims (x); sz = size (x); nel = numel (x); if (nargin != 2) ## Find the first non-singleton dimension. dim = 1; while (dim < nd + 1 && sz(dim) == 1) dim = dim + 1; endwhile if (dim > nd) dim = 1; endif else if (! (isscalar (dim) && dim == round (dim)) && dim > 0 && dim < (nd + 1)) error ("iqr: dim must be an integer and valid dimension"); endif endif ## This code is a bit heavy, but is needed until empirical_inv ## takes other than vector arguments. c = sz(dim); sz(dim) = 1; y = zeros (sz); stride = prod (sz(1:dim-1)); for i = 1 : nel / c; offset = i; offset2 = 0; while (offset > stride) offset -= stride; offset2++; endwhile offset += offset2 * stride * c; rng = [0 : c-1] * stride + offset; y (i) = empirical_inv (3/4, x(rng)) - empirical_inv (1/4, x(rng)); endfor endfunction